Clinical Focus

  • Anesthesiology
  • Cardiothoracic Anesthesiology
  • Cardiovascular Surgical Critical Care Medicine

Academic Appointments

  • Professor - Med Center Line, Anesthesiology, Perioperative and Pain Medicine

Administrative Appointments

  • Professor, Anesthesiology, Perioperative, and Pain Medicine, Stanford University, School of Medicine (2014 - Present)
  • Program Director, Adult Cardiothoracic Anesthesiology Fellowship, Stanford University, School of Medicine (2014 - Present)

Honors & Awards

  • John Morgan Society, University of Pennsylvania (2000-present)

Boards, Advisory Committees, Professional Organizations

  • Member, American Heart Association (2016 - Present)
  • Member, American Society of Anesthesiologists (2016 - Present)
  • Member, Society of Cardiovascular Anesthesiologists (2016 - Present)
  • President-Elect, Association of Cardiac Anesthesiologists (2016 - Present)

Professional Education

  • Medical Education:UC San Diego Office of the Registrar (1985) CA
  • Board Certification: Perioperative Transesophageal Echocardiography, American Board of Anesthesiology (2006)
  • Residency:Massachusetts General Hospital Anesthesiology ResidencyMA
  • Professor Emeritus, University of Pennsylvania, Department of Anesthesiology and Critical Care (2014)
  • Fellowship, Cardiac Anesthesia, Massachusetts General Hospital, Boston, MA (1990)
  • Fellowship:Massachusetts General HospitalMA
  • Fellowship, Department of Anesthesia, Massachusetts General Hospital, Boston, MA (1990)
  • Residency, Department of Anesthesia, Massachusetts General Hospital, Boston, MA (1989)
  • Internship, Baystate Medical Center, Springfield, MA (1986)
  • Internship:Baystate Medical Center
  • Board Certification: Anesthesiology, American Board of Anesthesiology (1991)
  • M.D., University of California, San Diego, La Jolla, California (1985)
  • B.A., John Hopkins University, Baltimore Maryland (1981)


2018-19 Courses

Graduate and Fellowship Programs

  • Cardiac Anesthesia (Fellowship Program)
  • Critical Care Medicine (Fellowship Program)


All Publications

  • Inhaled Nitric Oxide (iNO) and Inhaled Epoprostenol (iPGI(2)) Use in Cardiothoracic Surgical Patients: Is there Sufficient Evidence for Evidence-Based Recommendations? JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Rao, V., Ghadimi, K., Keeyapaj, W., Parsons, C. A., Cheung, A. T. 2018; 32 (3): 1452–57

    View details for DOI 10.1053/j.jvca.2017.12.014

    View details for Web of Science ID 000433384200059

    View details for PubMedID 29336971

  • Preventing Brain Injury After Cardiopulmonary Bypass Will Require More Than Just Dialing Up the Pressure CIRCULATION Cheung, A. T., Messe, S. R. 2018; 137 (17): 1781–83
  • Spatiotemporal Segmentation and Modeling of the Mitral Valve in Real-Time 3D Echocardiographic Images. Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention Pouch, A. M., Aly, A. H., Lai, E. K., Yushkevich, N., Stoffers, R. H., Gorman, J. H., Cheung, A. T., Gorman, J. H., Gorman, R. C., Yushkevich, P. A. 2017; 10433: 746–54


    Transesophageal echocardiography is the primary imaging modality for preoperative assessment of mitral valves with ischemic mitral regurgitation (IMR). While there are well known echocardiographic insights into the 3D morphology of mitral valves with IMR, such as annular dilation and leaflet tethering, less is understood about how quantification of valve dynamics can inform surgical treatment of IMR or predict short-term recurrence of the disease. As a step towards filling this knowledge gap, we present a novel framework for 4D segmentation and geometric modeling of the mitral valve in real-time 3D echocardiography (rt-3DE). The framework integrates multi-atlas label fusion and template-based medial modeling to generate quantitatively descriptive models of valve dynamics. The novelty of this work is that temporal consistency in the rt-3DE segmentations is enforced during both the segmentation and modeling stages with the use of groupwise label fusion and Kalman filtering. The algorithm is evaluated on rt-3DE data series from 10 patients: five with normal mitral valve morphology and five with severe IMR. In these 10 data series that total 207 individual 3DE images, each 3DE segmentation is validated against manual tracing and temporal consistency between segmentations is demonstrated. The ultimate goal is to generate accurate and consistent representations of valve dynamics that can both visually and quantitatively provide insight into normal and pathological valve function.

    View details for DOI 10.1007/978-3-319-66182-7_85

    View details for PubMedID 29285527

  • The value of preoperative 3-dimensional over 2-dimensional valve analysis in predicting recurrent ischemic mitral regurgitation after mitral annuloplasty. journal of thoracic and cardiovascular surgery Wijdh-den Hamer, I. J., Bouma, W., Lai, E. K., Levack, M. M., Shang, E. K., Pouch, A. M., Eperjesi, T. J., Plappert, T. J., Yushkevich, P. A., Hung, J., Mariani, M. A., Khabbaz, K. R., Gleason, T. G., Mahmood, F., Acker, M. A., Woo, Y. J., Cheung, A. T., Gillespie, M. J., Jackson, B. M., Gorman, J. H., Gorman, R. C. 2016; 152 (3): 847-859


    Repair for ischemic mitral regurgitation with undersized annuloplasty is characterized by high recurrence rates. We sought to determine the value of pre-repair 3-dimensional echocardiography over 2-dimensional echocardiography in predicting recurrence at 6 months.Intraoperative transesophageal 2-dimensional echocardiography and 3-dimensional echocardiography were performed in 50 patients undergoing undersized annuloplasty for ischemic mitral regurgitation. Two-dimensional echocardiography annular diameter and tethering parameters were measured in the apical 2- and 4-chamber views. A customized protocol was used to assess 3-dimensional annular geometry and regional leaflet tethering. Recurrence (grade ≥2) was assessed with 2-dimensional transthoracic echocardiography at 6 months.Preoperative 2- and 3-dimensional annular geometry were similar in all patients with ischemic mitral regurgitation. Preoperative 2- and 3-dimensional leaflet tethering were significantly higher in patients with recurrence (n = 13) when compared with patients without recurrence (n = 37). Multivariate logistic regression revealed preoperative 2-dimensional echocardiography posterior tethering angle as an independent predictor of recurrence with an optimal cutoff value of 32.0° (area under the curve, 0.81; 95% confidence interval, 0.68-0.95; P = .002) and preoperative 3-dimensional echocardiography P3 tethering angle as an independent predictor of recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84-1.00; P < .001). The predictive value of the 3-dimensional geometric multivariate model can be augmented by adding basal aneurysm/dyskinesis (area under the curve, 0.94; 95% confidence interval, 0.87-1.00; P < .001).Preoperative 3-dimensional echocardiography P3 tethering angle is a stronger predictor of ischemic mitral regurgitation recurrence after annuloplasty than preoperative 2-dimensional echocardiography posterior tethering angle, which is highly influenced by viewing plane. In patients with a preoperative P3 tethering angle of 29.9° or larger (especially when combined with basal aneurysm/dyskinesis), chordal-sparing valve replacement should be strongly considered.

    View details for DOI 10.1016/j.jtcvs.2016.06.040

    View details for PubMedID 27530639

  • Modeling the Myxomatous Mitral Valve With Three-Dimensional Echocardiography. Annals of thoracic surgery Pouch, A. M., Jackson, B. M., Lai, E., Takebe, M., Tian, S., Cheung, A. T., Woo, Y. J., Patel, P. A., Wang, H., Yushkevich, P. A., Gorman, R. C., Gorman, J. H. 2016; 102 (3): 703-710


    Degenerative mitral valve disease is associated with variable and complex defects in valve morphology. Three-dimensional echocardiography (3DE) has shown promise in aiding preoperative planning for patients with this disease but to date has not been as transformative as initially predicted. The clinical usefulness of 3DE has been limited by the laborious methods currently required to extract quantitative data from the images.To maximize the utility of 3DE for preoperative valve evaluation, this work describes an automated 3DE image analysis method for generating models of the mitral valve that are well suited for both qualitative and quantitative assessment. The method is unique in that it captures detailed alterations in mitral leaflet and annular morphology and produces image-derived models with locally varying leaflet thickness. The method is evaluated on midsystolic transesophageal 3DE images acquired from 22 subjects with myxomatous degeneration and from 22 subjects with normal mitral valve morphology.Relative to manual image analysis, the automated method accurately represents both normal and complex leaflet geometries with a mean boundary displacement error on the order of one image voxel. A detailed quantitative analysis of the valves is presented and reveals statistically significant differences between normal and myxomatous valves with respect to numerous aspects of annular and leaflet geometry.This work demonstrates a successful methodology for the relatively rapid quantitative description of the complex mitral valve distortions associated with myxomatous degeneration. The methodology has the potential to significantly improve surgical planning for patients with complex mitral valve disease.

    View details for DOI 10.1016/j.athoracsur.2016.05.087

    View details for PubMedID 27492671

  • Protocol for prevention of spinal cord ischemia after thoracoabdominal aortic surgery. Vascular Hobbs, R. D., Ullery, B. W., Mentzer, A. R., Cheung, A. T. 2016; 24 (4): 430-434


    This manuscript was written to present a systemic protocol for the prevention, early detection, and treatment of spinal cord ischemia following open and endovascular thoracoabdominal aortic operations.This protocol was a collaborative effort between surgeons, anesthesiologists and intensivists. It was implemented at our institution in November 2007. Nurses are trained to prevent, rapidly detect and ultimately aid in the treatment of spinal cord ischemia.Implementation of this protocol has aided in prevention, detection and treatment of spinal cord ischemia in patients after open and endovascular thoracoabdominal aortic operations.Standardized care and reliance on trained nursing staff to monitor for symptoms following thoracoabdominal aortic operations are safe and aid in the rapid detection, treatment and reversal of spinal cord ischemia.

    View details for DOI 10.1177/1708538115593193

    View details for PubMedID 26113574

  • Sodium bicarbonate use and the risk of hypernatremia in thoracic aortic surgical patients with metabolic acidosis following deep hypothermic circulatory arrest. Annals of cardiac anaesthesia Ghadimi, K., Gutsche, J. T., Ramakrishna, H., Setegne, S. L., Jackson, K. R., Augoustides, J. G., Ochroch, E. A., Weiss, S. J., Bavaria, J. E., Cheung, A. T. 2016; 19 (3): 454-462


    Metabolic acidosis after deep hypothermic circulatory arrest (DHCA) for thoracic aortic operations is commonly managed with sodium bicarbonate (NaHCO 3 ). The purpose of this study was to determine the relationships between total NaHCO 3 dose and the severity of metabolic acidosis, duration of mechanical ventilation, duration of vasoactive infusions, and Intensive Care Unit (ICU) or hospital length of stay (LOS).In a single center, retrospective study, 87 consecutive elective thoracic aortic operations utilizing DHCA, were studied. Linear regression analysis was used to test for the relationships between the total NaHCO 3 dose administered through postoperative day 2, clinical variables, arterial blood gas values, and short-term clinical outcomes.Seventy-five patients (86%) received NaHCO 3 . Total NaHCO 3 dose averaged 136 ± 112 mEq (range: 0.0-535 mEq) per patient. Total NaHCO 3 dose correlated with minimum pH (r = 0.41, P < 0.0001), minimum serum bicarbonate (r = -0.40, P < 0.001), maximum serum lactate (r = 0.46, P = 0.007), duration of metabolic acidosis (r = 0.33, P = 0.002), and maximum serum sodium concentrations (r = 0.29, P = 0.007). Postoperative hypernatremia was present in 67% of patients and peaked at 12 h following DHCA. Eight percent of patients had a serum sodium ≥ 150 mEq/L. Total NaHCO 3 dose did not correlate with anion gap, serum chloride, not the duration of mechanical ventilator support, vasoactive infusions, ICU or hospital LOS.Routine administration of NaHCO 3 was common for the management of metabolic acidosis after DHCA. Total dose of NaHCO 3 was a function of the severity and duration of metabolic acidosis. NaHCO 3 administration contributed to postoperative hypernatremia that was often severe. The total NaHCO 3 dose administered was unrelated to short-term clinical outcomes.

    View details for DOI 10.4103/0971-9784.185527

    View details for PubMedID 27397449

  • Preoperative Three-Dimensional Valve Analysis Predicts Recurrent Ischemic Mitral Regurgitation After Mitral Annuloplasty ANNALS OF THORACIC SURGERY Bouma, W., Lai, E. K., Levack, M. M., Shang, E. K., Pouch, A. M., Eperjesi, T. J., Plappert, T. J., Yushkevich, P. A., Mariani, M. A., Khabbaz, K. R., Gleason, T. G., Mahmood, F., Acker, M. A., Woo, Y. J., Cheung, A. T., Jackson, B. M., Gorman, J. H., Gorman, R. C. 2016; 101 (2): 567-575
  • Medially constrained deformable modeling for segmentation of branching medial structures: Application to aortic valve segmentation and morphometry MEDICAL IMAGE ANALYSIS Pouch, A. M., Tian, S., Takebe, M., Yuan, J., Gorman, R., Cheung, A. T., Wang, H., Jackson, B. M., Gorman, J. H., Gorman, R. C., Yushkevich, P. A. 2015; 26 (1): 217-231
  • Severity and Duration of Metabolic Acidosis After Deep Hypothermic Circulatory Arrest for Thoracic Aortic Surgery JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Ghadimi, K., Gutsche, J. T., Setegne, S. L., Jackson, K. R., Augoustides, J. G., Ochroch, E. A., Bavaria, J. E., Cheung, A. T. 2015; 29 (6): 1432-1440


    To determine the severity, duration, and contributing factors for metabolic acidosis after deep hypothermic circulatory arrest (DHCA).Retrospective observational study.University hospital.Eighty-seven consecutive patients undergoing elective thoracic aortic surgery with DHCA.Regression analysis was used to test for relationships between the severity of metabolic acidosis and clinical and laboratory variables.Minimum pH averaged 7.27±0.06, with 76 (87%) having a pH<7.35; 55 (63%), a pH<7.30; and 7 (8%), a pH<7.20. The mean duration of metabolic acidosis was 7.9±5.0 hours (range: 0.0 - 26.8), and time to minimum pH after DHCA was 4.3±2.0 hours (1.0 - 10.0 hours). Hyperchloremia contributed to metabolic acidosis in 89% of patients. The severity of metabolic acidosis correlated with maximum lactate (p<0.0001) and hospital length of stay (LOS) (r = 0.22, p<0.05), but not with DHCA time, DHCA temperature, duration of vasoactive infusions, or ICU LOS. Patient BMI was the sole preoperative predictor of the severity of postoperative metabolic acidosis.This retrospective analysis involved short-term clinical outcomes related to pH severity and duration, which indirectly may have included the impact of sodium bicarbonate administration.Metabolic acidosis was common and severe after DHCA and was attributed to both lactic and hyperchloremic acidosis. DHCA duration and temperature had little impact on the severity of metabolic acidosis. The severity of metabolic acidosis was best predicted by the BMI and had minimal effects on short-term outcomes. Preventing hyperchloremic acidosis has the potential to decrease the severity of metabolic acidosis after DHCA.

    View details for DOI 10.1053/j.jvca.2015.07.025

    View details for Web of Science ID 000367421800006

    View details for PubMedID 26706792

  • Pro: Patients at Risk for Spinal Cord Ischemia After Thoracic Endovascular Aortic Repairs Should Receive Prophylactic Cerebrospinal Fluid Drainage. Journal of cardiothoracic and vascular anesthesia Arora, H., Ullery, B. W., Kumar, P. A., Cheung, A. T. 2015; 29 (5): 1376-1380

    View details for DOI 10.1053/j.jvca.2015.05.192

    View details for PubMedID 26384635

  • Reversible spinal cord ischemia as a complication of acute aortic intramural hematoma VASCULAR Ullery, B. W., Hobbs, R. D., Cheung, A. T. 2015; 23 (4): 427-431


    Aortic intramural hematoma is a variant of acute aortic dissection characterized by localized hemorrhage into the aortic media causing a separation of the intimal and adventitial layers of the aorta. Malperfusion represents an unusual presenting sign of acute intramural hematoma. Herein, we describe the case of a patient with an acute Type A IMH who developed reversible ischemic spinal cord syndrome after presenting with paraplegia as a consequence of malperfusion. A decision was made to delay operative repair and, instead, emergently apply medical interventions to increase spinal cord perfusion pressure. Medical treatment was effective for the treatment of spinal cord ischemia and operative repair of the intramural hematoma was accomplished after complete recovery of neurologic function. This is the third case ever reported of an intramural hematoma presenting in the form of spinal cord ischemia.

    View details for DOI 10.1177/1708538114549067

    View details for Web of Science ID 000357518700014

    View details for PubMedID 25193357

  • Regional Annular Geometry in Patients With Mitral Regurgitation: Implications for Annuloplasty Ring Selection ANNALS OF THORACIC SURGERY Jassar, A. S., Vergnat, M., Jackson, B. M., McGarvey, J. R., Cheung, A. T., Ferrari, G., Woo, Y. J., Acker, M. A., Gorman, R. C., Gorman, J. H. 2014; 97 (1): 64-70


    The saddle shape of the normal mitral annulus has been quantitatively described by several groups. There is strong evidence that this shape is important to valve function. A more complete understanding of regional annular geometry in diseased valves may provide a more educated approach to annuloplasty ring selection and design. We hypothesized that mitral annular shape is markedly distorted in patients with diseased valves.Real-time 3-dimensional echocardiography was performed in 20 patients with normal mitral valves, 10 with ischemic mitral regurgitation, and 20 with myxomatous mitral regurgitation (MMR). Thirty-six annular points were defined to generate a 3-dimensional model of the annulus. Regional annular parameters were measured from these renderings. Left ventricular inner diameter was obtained from 2-dimensional echocardiographic images.Annular geometry was significantly different among the three groups. The annuli were larger in the MMR and in the ischemic mitral regurgitation groups. The annular enlargement was greater and more pervasive in the MMR group. Both diseases were associated with annular flattening, although though the regional distribution of that flattening was different between groups. Left ventricular inner diameter was increased in both groups. However, relative to the Left ventricular inner diameter, the annulus was disproportionately dilated in the MMR group.Patients with MMR and ischemic mitral regurgitation have enlarged and flattened annuli. In the case of MMR, annular distortions may be the driving factor leading to valve incompetence. These data suggest that the goal of annuloplasty should be the restoration of normal annular saddle shape and that the use of flexible, partial, and flat rings may be ill advised.

    View details for DOI 10.1016/j.athoracsur.2013.07.048

    View details for Web of Science ID 000329155900020

    View details for PubMedID 24070698

  • A Pilot Study of Darbepoetin Alfa for Prophylactic Neuroprotection in Aortic Surgery NEUROCRITICAL CARE Messe, S. R., McGarvey, M. L., Bavaria, J. E., Pochettino, A., Szeto, W. Y., Cheung, A. T., Leitner, E., Miller, S. W., Kasner, S. E. 2013; 18 (1): 75-80


    Descending aortic (DA) surgery poses a high risk for spinal and cerebral infarction and routine use of lumbar drains allows for measurement of CSF markers of neurologic injury. Erythropoiesis medications have extensive preclinical data demonstrating neuroprotection. We hypothesized that prophylactic darbepoetin alfa (DARB) given before surgery reduces neurologic injury in patients undergoing DA repair.We performed a prospective adaptive dose-finding trial of prophylactic DARB ( NCT00647998) that terminated prematurely following publication of an erythropoietin stroke study showing possible harm. Enrollment halted before dose adjustments; nine patients each received 1 mg/kg IV DARB immediately before surgery. A prospective cohort of nine untreated patients was subsequently obtained for comparison. The primary outcome of death or neurologic impairment at discharge occurred in 1/9 (11 %) DARB patients and 3/9 (33 %) controls (p = 0.58). There were no statistical differences in changes of CSF biomarkers from baseline to 48 h comparing DARB patients to controls: S100β, median 214 versus 260 ng/ml (p = 0.69); glial fibrillary acidic protein (GFAP), median 0.022 versus 0.58 ng/ml (p = 0.45). In patients with early perioperative neurologic ischemia, there were greater changes in CSF biomarkers, compared to those without ischemia: S100β, median 2301 versus 124 ng/ml (p = 0.04); GFAP, median 31.78 versus 0.31 ng/ml (p = 0.34).There were no significant effects of prophylactic DARB on clinical outcome or CSF markers of neurologic injury in this pilot study, although all point estimates favored treatment. DA repair is a promising model of prophylactic neuroprotection.

    View details for DOI 10.1007/s12028-012-9710-4

    View details for Web of Science ID 000314708500013

    View details for PubMedID 22528284

  • Vascular distribution of stroke and its relationship to perioperative mortality and neurologic outcome after thoracic endovascular aortic repair JOURNAL OF VASCULAR SURGERY Ullery, B. W., McGarvey, M., Cheung, A. T., Fairman, R. M., Jackson, B. M., Woo, E. Y., Desai, N. D., Wang, G. J. 2012; 56 (6): 1510-1517


    This study assessed the vascular distribution of stroke after thoracic endovascular aortic repair (TEVAR) and its relationship to perioperative death and neurologic outcome.A retrospective review was performed for patients undergoing TEVAR between 2001 and 2010. Aortic arch hybrid and abdominal debranching cases were excluded. Demographics, operative variables, and neurologic complications were examined. Stroke was defined as any new focal or global neurologic deficit lasting>24 hours with radiographic confirmation of acute intracranial pathology.Perioperative stroke occurred in 20 of 530 patients (3.8%) undergoing TEVAR. The cohort was 55% male and a mean age of 75.2±8.9 years (range, 57-90 years). Among patients with perioperative strokes, the indication for surgery was degenerative aneurysm in 14 (mean diameter, 6.8 cm), acute type B dissection in four, penetrating atherosclerotic aneurysm in one, and aortic transection in one. Cases were performed urgently or as an emergency in 60%. The proximal landing zone was zone 2 in 11 or zone 3 in nine. All strokes were embolic. The vascular distribution of stroke involved the anterior cerebral (AC) circulation in eight (zone 2, n=5) and the posterior cerebral (PC) circulation in 12 (zone 2, n=6). Laterality of cerebral infarction included five right-sided, eight left-sided, and seven bilateral strokes. Nine strokes were diagnosed<24 hours after operation. There was no difference in baseline demographics, aortic pathology, acuity, zone coverage, preoperative left subclavian artery revascularization, number of stents, or estimated blood loss between stroke groups based on vascular distribution. Independent risk factors for any perioperative stroke were chronic renal insufficiency (odds ratios [OR], 4.65; 95% confidence interval [CI], 1.22-17.7; P=.02) and history of prior stroke (OR, 4.92; 95% CI, 1.69-14.4; P=.004); the risk factor for AC stroke was prior stroke (OR, 7.67; 95% CI, 1.25-46.9; P=.03) and the risk factors for PC stroke were age (OR, 1.11; 95% CI, 1.00-1.23; P=.04), prior stroke (OR, 7.53; 95% CI, 1.78-31.8; P=.006), zone 2 coverage (OR, 6.11; 95% CI, 1.15-32.3; P=.03), and penetrating atherosclerotic ulcer (OR, 32.7; 95% CI, 1.33-807.2; P=.03). Overall in-hospital mortality was 20% (n=4), with those sustaining PC strokes observed to trend toward increased mortality (33% vs 0%; P=.12). Patients with AC strokes were more likely than those with PC strokes to achieve complete recovery of neurologic deficits before discharge (75% vs 17%; P=.02).Perioperative stroke after TEVAR is primarily an embolic event. Although infrequent, stroke was associated with significant morbidity and death, particularly among those with strokes involving the PC circulation.

    View details for DOI 10.1016/j.jvs.2012.05.086

    View details for Web of Science ID 000311489800004

    View details for PubMedID 22841287

  • Neurological complications of thoracic endovascular aortic repair. Seminars in cardiothoracic and vascular anesthesia Ullery, B. W., Wang, G. J., Low, D., Cheung, A. T. 2011; 15 (4): 123-140


    Thoracic endovascular aortic repair (TEVAR) has decreased the morbidity and mortality associated with open surgical repair of descending thoracic aortic diseases, but important complications unique to the procedure remain. Spinal cord ischemia and infarction is a recognized complication caused by endovascular coverage or injury to spinal cord collateral vessels. Stroke is a consequence of thromboembolism or coverage of aortic arch branch vessels with insufficient collateral circulation. Understanding the risk factors and the pathophysiology of neurological complications of TEVAR are important for the successful anesthetic and surgical management and treatment of patients undergoing endovascular procedures involving the thoracic aorta.

    View details for DOI 10.1177/1089253211424224

    View details for PubMedID 22025398

  • Saddle-shape annuloplasty increases mitral leaflet coaptation after repair for flail posterior leaflet. Annals of thoracic surgery Vergnat, M., Jackson, B. M., Cheung, A. T., Weiss, S. J., Ratcliffe, S. J., Gillespie, M. J., Woo, Y. J., Bavaria, J. E., Acker, M. A., Gorman, R. C., Gorman, J. H. 2011; 92 (3): 797-803


    The primary goal of surgical mitral repair is the reestablishment of normal leaflet coaptation. Surgical techniques that maintain or restore leaflet geometry promote leaflet coaptation. Recent 3-dimensional (3D) echocardiographic studies have shown that saddle-shaped annuloplasty has a salutary influence on leaflet geometry. Therefore we hypothesized that saddle-shaped annuloplasty would improve leaflet coaptation in cases of repair for flail posterior leaflet segments.Sixteen patients with flail posterior segment and severe mitral regurgitation had valve repair using standard techniques. Eight patients received saddle-shaped annuloplasty and 8 patients received flat annuloplasty. Real-time 3D transesophageal echocardiography was performed before and after repair. Images were analyzed using custom software to calculate mitral annular area (MAA), septolateral dimension (SLD), intercommissural width (CW), total leaflet area (TLA), and leaflet coaptation area (LCA).Postrepair MAA (flat, 588.6±26.5 mm2; saddle, 628.0±35.3 mm2; p=0.12) and TLA (flat, 2198.5±151.6 mm2; saddle, 2303.9±183.8 mm2; p=0.67) were similar in both groups. Postrepair LCA was significantly greater in the saddle group than in the flat group (226.8±24.0 mm2 and 154.0±13.0 mm2, respectively; p=0.02).Real-time 3D echocardiography and novel imaging software provide a powerful tool for analyzing mitral leaflet coaptation. When compared with flat annuloplasty, saddle-shaped annuloplasty improves LCA after mitral valve repair for severe mitral regurgitation secondary to flail posterior leaflet segment. Use of saddle-shaped annuloplasty devices may increase repair durability.

    View details for DOI 10.1016/j.athoracsur.2011.04.047

    View details for PubMedID 21803330

  • Risk factors, outcomes, and clinical manifestations of spinal cord ischemia following thoracic endovascular aortic repair 39th Annual Symposium of the Society-for-Clinical-Vascular-Surgery Ullery, B. W., Cheung, A. T., Fairman, R. M., Jackson, B. M., Woo, E. Y., Bavaria, J., Pochettino, A., Wang, G. J. MOSBY-ELSEVIER. 2011: 677–84


    The purpose of this study was to assess the incidence, risk factors, and clinical manifestations of spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR).A retrospective review of a prospectively collected database was performed for all patients undergoing TEVAR at a single academic institution between July 2002 and June 2010. Preoperative demographics, procedure-related variables, and clinical details related to SCI were examined. Logistic regression analysis was performed to identify risk factors for the development of SCI.Of the 424 patients who underwent TEVAR during the study period, 12 patients (2.8%) developed SCI. Mean age of this cohort with SCI was 69.6 years (range, 44-84 years), and 7 were women. One-half of these patients had prior open or endovascular aortic repair. Indication for surgery was either degenerative aneurysm (n = 8) or dissection (n = 4). Six TEVARs were performed electively, with the remaining done either urgently or emergently due to contained rupture (n = 2), dissection with malperfusion (n = 2), or severe back pain (n = 2). All 12 patients underwent extent C endovascular coverage. Multivariate regression analysis demonstrated chronic renal insufficiency to be independently associated with SCI (odds ratio [OR], 4.39; 95% confidence interval [CI], 1.2-16.6; P = .029). Onset of SCI occurred at a median of 10.6 hours (range, 0-229 hours) postprocedure and was delayed in 83% (n = 10) of patients. Clinical manifestations of SCI included lower extremity paraparesis in 9 patients and paraplegia in 3 patients. At SCI onset, average mean arterial pressure (MAP) and lumbar cerebrospinal fluid (CSF) pressure was 77 mm Hg and 10 mm Hg, respectively. Therapeutic interventions increased blood pressure to a significantly higher average MAP of 99 mm Hg (P = .001) and decreased lumbar CSF pressure to a mean of 7 mm Hg (P = .30) at the time of neurologic recovery. Thirty-day mortality was 8% (1 of 12 patients). The single patient who expired, never recovered any lower extremity neurologic function. All patients surviving to discharge experienced either complete (n = 9) or incomplete (n = 2) neurologic recovery. At mean follow-up of 49 months, 7 of 9 patients currently alive continued to exhibit complete, sustained neurologic recovery.Spinal cord ischemia after TEVAR is an uncommon, but important complication. Preoperative renal insufficiency was identified as a risk factor for the development of SCI. Early detection and treatment of SCI with blood pressure augmentation alone or in combination with CSF drainage was effective in most patients, with the majority achieving complete, long-term neurologic recovery.

    View details for DOI 10.1016/j.jvs.2011.03.259

    View details for Web of Science ID 000294505300010

    View details for PubMedID 21571494

  • Reversal of Delayed-Onset Paraparesis After Revision Thoracic Endovascular Aortic Repair For Ruptured Thoracic Aortic Aneurysm ANNALS OF VASCULAR SURGERY Ullery, B. W., Cheung, A. T., McGarvey, M. L., Jackson, B. M., Wang, G. J. 2011; 25 (6)


    Thoracic endovascular aortic repair (TEVAR) is an important surgical option for the emergency treatment of ruptured thoracic aortic aneurysms, but is associated with a risk of spinal cord ischemia (SCI). Although risk factors for the development of SCI have been well described, the effectiveness of treatment to increase spinal cord perfusion pressure remains incompletely understood. We report the successful treatment of delayed-onset paraparesis after revision TEVAR for acute descending thoracic aortic rupture with the combined use of blood pressure augmentation and cerebrospinal fluid drainage. The clinical manifestations, pathophysiology, and management of SCI after TEVAR are reviewed.

    View details for DOI 10.1016/j.avsg.2010.12.043

    View details for Web of Science ID 000293269500028

    View details for PubMedID 21621971

  • Classification of acute type a dissection: focus on clinical presentation and extent EUROPEAN JOURNAL OF CARDIO-THORACIC SURGERY Augoustides, J. G., Szeto, W. Y., Desai, N. D., Pochettino, A., Cheung, A. T., Savino, J. S., Bavaria, J. E. 2011; 39 (4): 519-522


    Recent advances in the management of acute Stanford type A dissection have highlighted the clinical importance of clinical presentation and extent of dissection. The Penn classification of type A clinical presentations is based on ischemic profiles that not only determine mortality but also influence management options. The extent of type A dissection as summarized by the DeBakey classification significantly determines the role of endovascular intervention in this important disease. We propose an integration of these three classifications of acute type A dissection as a framework for future advances in diagnosis, intervention and prognosis.

    View details for DOI 10.1016/j.ejcts.2010.05.038

    View details for Web of Science ID 000289341100014

    View details for PubMedID 20615719

  • Ischemic Mitral Regurgitation: A Quantitative Three-Dimensional Echocardiographic Analysis ANNALS OF THORACIC SURGERY Vergnat, M., Jassar, A. S., Jackson, B. M., Ryan, L. P., Eperjesi, T. J., Pouch, A. M., Weiss, S. J., Cheung, A. T., Acker, M. A., Gorman, J. H., Gorman, R. C. 2011; 91 (1): 157-164


    A comprehensive three-dimensional echocardiography based approach is applied to preoperative mitral valve (MV) analysis in patients with ischemic mitral regurgitation (IMR). This method is used to characterize the heterogeneous nature of the pathologic anatomy associated with IMR.Intraoperative real-time three-dimensional transesophageal echocardiograms of 18 patients with IMR (10 with anterior, 8 with inferior infarcts) and 17 patients with normal MV were analyzed. A customized image analysis protocol was used to assess global and regional determinants of annular size and shape, leaflet tethering and curvature, relative papillary muscle anatomy, and anatomic regurgitant orifice area.Both mitral annular area and MV tenting volume were increased in the IMR group as compared with patients with normal MV (mitral annular area=1,065±59 mm2 versus 779±44 mm2, p=0.001; and MV tenting volume=3,413±403 mm3 versus 1,696±200 mm3, p=0.001, respectively). Within the IMR group, patients with anterior infarct had larger annuli (1,168±99 mm2) and greater tenting volumes (4,260±779 mm3 versus 2,735±245 mm3, p=0.06) than the inferior infarct subgroup. Papillary-annular distance was increased in the IMR group relative to normal; these distances were largest in patients with anterior infarcts. Whereas patients with normal MV had very consistent anatomic determinants, annular shape and leaflet tenting distribution in the IMR group were exceedingly variable. Mean anatomic regurgitant orifice area was 25.8±3.0 mm2, and the number of discrete regurgitant orifices varied from 1 to 4.Application of custom analysis techniques to three-dimensional echocardiography images allows a quantitative and systematic analysis of the MV, and demonstrates the extreme variability in pathologic anatomy that occurs in patients with severe IMR.

    View details for DOI 10.1016/j.athoracsur.2010.09.078

    View details for Web of Science ID 000285411700030

    View details for PubMedID 21172506

  • The ECLIPSE trials: Comparative studies of clevidipine to nitroglycerin, sodium nitroprusside, and nicardipine for acute hypertension treatment in cardiac surgery patients ANESTHESIA AND ANALGESIA Aronson, S., Dyke, C. M., Stierer, K. A., Levy, J. H., Cheung, A. T., Lumb, P. D., Kereiakes, D. J., Newman, M. F. 2008; 107 (4): 1110-1121


    Acute hypertension during cardiac surgery can be difficult to manage and may adversely affect patient outcomes. Clevidipine is a novel, rapidly acting dihydropyridine L-type calcium channel blocker with an ultrashort half-life that decreases arterial blood pressure (BP). The Evaluation of CLevidipine In the Perioperative Treatment of Hypertension Assessing Safety Events trial (ECLIPSE) was performed to compare the safety and efficacy of clevidipine (CLV) with nitroglycerin (NTG), sodium nitroprusside (SNP), and nicardipine (NIC) in the treatment of perioperative acute hypertension in patients undergoing cardiac surgery.We analyzed data from three prospective, randomized, open-label, parallel comparison studies of CLV to NTG or SNP perioperatively, or NIC postoperatively in patients undergoing cardiac surgery at 61 medical centers. Of the 1964 patients enrolled, 1512 met postrandomization inclusion criteria of requiring acute treatment of hypertension based on clinical criteria. The patients were randomized 1:1 for each of the three parallel comparator treatment groups. The primary outcome was the incidence of death, myocardial infarction, stroke or renal dysfunction at 30 days. Adequacy and precision of BP control was evaluated and is reported as a secondary outcome.There was no difference in the incidence of myocardial infarction, stroke or renal dysfunction for CLV-treated patients compared with the other treatment groups. There was no difference in mortality rates between the CLV, NTG or NIC groups. Mortality was significantly higher, though, for SNP-treated patients compared with CLV-treated patients (P=0.04). CLV was more effective compared with NTG (P=0.0006) or SNP (P=0.003) in maintaining BP within the prespecified BP range. CLV was equivalent to NIC in keeping patients within a prespecified BP range; however, when BP range was narrowed, CLV was associated with fewer BP excursions beyond these BP limits compared with NIC.CLV is a safe and effective treatment for acute hypertension in patients undergoing cardiac surgery.

    View details for DOI 10.1213/ane.0b013e31818240db

    View details for Web of Science ID 000259522100006

    View details for PubMedID 18806012

  • Endovascular stenting of thoracic aortic aneurysm. Anesthesiology clinics Gutsche, J. T., Szeto, W., Cheung, A. T. 2008; 26 (3): 481-499


    In 2005, the findings of the multicenter Gore Tag study led to United States Food and Drug Administration approval for endovascular repair of thoracic aortic aneurysms (TEVAR). TEVAR provides a therapeutic option for patients who have thoracic aortic aneurysm and for the treatment of type B aortic dissection with malperfusion. Spinal cord ischemia and stroke are recognized neurologic complications of TEVAR. Identification of high-risk patients combined with targeted anesthetic and perioperative management may decrease the risk of neurologic complications after TEVAR.

    View details for DOI 10.1016/j.anclin.2008.03.006

    View details for PubMedID 18765219

  • Risk factors for perioperative stroke after thoracic endovascular aortic repair 43rd Annual Meeting of the Society-of-Thoracic-Surgeons Gutsche, J. T., Cheung, A. T., McGarvey, M. L., Moser, W. G., Szeto, W., Carpenter, J. P., Fairman, R. M., Pochettino, A., Bavaria, J. E. ELSEVIER SCIENCE INC. 2007: 1195–1200


    Stroke has emerged as an important complication of thoracic endovascular aortic repair (TEVAR). Identifying risk factors for stroke is important to define the risks of this procedure.All neurologic complications were analyzed in a prospective database of patients in thoracic aortic stent graft trials from 1999 to 2006. Serial neurological examination was performed. Stroke was defined as any new onset focal neurologic deficit.The TEVAR was performed on 171 patients; 52 had lesions requiring coverage of the proximal descending thoracic aorta (extent A), 50 requiring coverage of the distal descending aorta (extent B), and 69 requiring coverage of the entire descending thoracic aorta (extent C). The incidence of stroke was 5.8%. Eighty-nine percent (8 of 9) of strokes occurred within 24 hours of operation. Stroke was associated with a 33% in-hospital mortality rate. Risk factors identified for stroke included prior stroke (odds ratio [OR] 9.4, confidence interval [CI] 2.3 to 38.1, p = 0.002) and extent A or C coverage (OR 5.5, CI 1.7-12.5, p = 0.001). The stroke rate in patients with both prior stroke and extent A or C coverage was 27.7%. Severe atheromatous disease involving the aortic arch by computed tomographic scan was strongly associated with perioperative stroke (OR = 14.8, CI 1.7 to 675.6, p = 0.0016). Transesophageal echocardiography demonstrated mobile atheroma in two patients with stroke.Stroke after TEVAR was associated with a high mortality. The TEVAR of the proximal descending aorta (extent A or C) in patients with a history of stroke had the highest perioperative stroke rate. These risk factors, together with high grade aortic atheroma of the aortic arch, predicted a high probability for cerebral embolization and can be used to identify patients at high risk for stroke as a consequence of TEVAR.

    View details for DOI 10.1016/j.athoracsur.2007.04.128

    View details for Web of Science ID 000249595600021

    View details for PubMedID 17888969

  • Cardiopulmonary bypass, hemolysis, and nitroprusside-induced cyanide production ANESTHESIA AND ANALGESIA Cheung, A. T., Cruz-Shiavone, G. E., Meng, Q. C., Pochettino, A., Augoustides, J. A., Bavaria, J. E., Ochroch, E. A. 2007; 105 (1): 29-33


    Cyanide toxicity is a complication of sodium nitroprusside administration. Cardiac surgery may increase the risk of cyanide toxicity, because hemolysis during cardiopulmonary bypass (CPB) may catalyze the release of free cyanide from sodium nitroprusside.We obtained serial blood specimens from 25 cardiac surgical patients during CPB. Plasma specimens were analyzed for free hemoglobin concentration and ability to generate free cyanide anion upon exposure to sodium nitroprusside.Hemolysis based on plasma-free hemoglobin concentration increased over time during CPB at an average rate of 0.27 mg x dL(-1) x min(-1) (P < 0.001). The concentration of free cyanide generated by the addition of sodium nitroprusside to the plasma samples was directly related to the plasma-free hemoglobin concentration (P < 0.001).CPB-associated hemolysis and free hemoglobin release accelerated the immediate release of free cyanide from sodium nitroprusside. These in vitro findings suggest that cardiac surgical patients may be at increased risk of cyanide toxicity in response to the perioperative administration of sodium nitroprusside.

    View details for DOI 10.1213/01.ane.0000264078.34514.32

    View details for Web of Science ID 000247444800009

    View details for PubMedID 17578949

  • Images in cardiovascular medicine. Rib perforation from a right ventricular pacemaker lead. Circulation Singhal, S., Cooper, J. M., Cheung, A. T., Acker, M. A. 2007; 115 (14): e391-2

    View details for PubMedID 17420357

  • Techniques for preserving vertebral artery perfusion during thoracic aortic stent grafting requiring aortic arch landing. Vascular and endovascular surgery Woo, E. Y., Bavaria, J. E., Pochettino, A., Gleason, T. G., Woo, Y. J., Velazquez, O. C., Carpenter, J. P., Cheung, A. T., Fairman, R. M. 2006; 40 (5): 367-373


    Thoracic endografting offers many advantages over open repair. However, delivery of the device can be difficult and may necessitate adjunctive procedures. We describe our techniques for preserving perfusion to the left subclavian artery despite endograft coverage to obtain a proximal seal zone. We reviewed our experience with the Talent thoracic stent graft (Medtronic, Santa Rosa, CA). From 1999 to 2003, 49 patients received this device (29 men, 20 women). Seventeen patients required adjunctive procedures to facilitate proximal graft placement. We performed left subclavian-to-left common carotid artery transposition (6), left common carotid-to-left subclavian artery bypass with ligation proximal to the vertebral artery (7), and left common carotid-to-left subclavian artery bypass with proximal coil embolization (4). Patients who had anatomy unfavorable to transposition or bypass with proximal ligation (large aneurysms or proximal vertebral artery origin) were treated with coil embolization of the proximal left subclavian artery in order to prevent subsequent type II endoleaks. Technical success rate of the carotid subclavian bypass was 100%. Patient follow-up ranged from 3 to 48 months with a mean of 12 months. Six patients had follow-up <6 months owing to recent graft placement. Primary patency was 100%. No neurologic events occurred during the procedure or upon follow-up. One patient had a transient chyle leak that spontaneously resolved in 24 hours. Another patient had a phrenic nerve paresis that resolved after 3 weeks. We believe that it is important to maintain patency of the vertebral artery specifically when a patent right vertebral system and an intact basilar artery is not demonstrated. Furthermore, we describe a novel technique of coil embolization of the proximal left subclavian artery in conjunction with left common carotid-to-left subclavian artery bypass. This circumvents the need for potentially hazardous mediastinal dissection and ligation of the proximal left subclavian artery in cases of large proximal aneurysms or unfavorable vertebral artery anatomy.

    View details for PubMedID 17038570

  • Perioperative outcome in adults undergoing elective deep hypothermic circulatory arrest with retrograde cerebral perfusion in proximal aortic arch repair: Evaluation of protocol-based care JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Appoo, J. J., Augoustides, J. G., Pochettino, A., Savino, J. S., McGarvey, M. L., Cowie, D. C., Gambone, A. J., Harris, H., Cheung, A. T., Bavaria, J. E. 2006; 20 (1): 3-7


    The purpose of this study was to describe perioperative outcome in adults undergoing elective proximal aortic arch repair with protocol-based deep hypothermic circulatory arrest (DHCA) with retrograde cerebral perfusion (RCP).Retrospective and observational.Cardiothoracic operating rooms and intensive care unit.Seventy-nine consecutive adults undergoing elective proximal aortic arch repair with DHCA (1999-2001).None.Average age of the patients was 64.9 years. Mean circulatory arrest time was 30.4 +/- 8.5 minutes. Perioperative mortality was 7.6%. Perioperative stroke incidence was 3.8%. Tracheal extubation was successful in 87.3% of patients within 24 hours of operation. Of the cohort, 80.8% were discharged from the intensive care unit within 72 hours of surgery. Median length of hospital stay was 7.4 days. Repeat mediastinal exploration because of bleeding occurred in 3.8% of patients. Although perioperative renal dysfunction (defined as >1.5-fold increase in plasma creatinine concentration) developed in 24.0% of patients, only 3.8% required dialysis.The above parameters establish a baseline incidence for major perioperative complications in adults undergoing elective DHCA with RCP for elective proximal aortic arch repair. In approaching the open aortic arch for short periods of circulatory arrest, deep hypothermia with adjunctive RCP is safe and effective.

    View details for DOI 10.1053/j.jvca.2005.08.005

    View details for Web of Science ID 000235490300002

    View details for PubMedID 16458205

  • Strategies to manage paraplegia risk after endovascular stent repair of descending thoracic aortic aneurysms 41st Annual Meeting of the Society-of-Thoracic-Surgeons Cheung, A. T., Pochettino, A., McGarvey, M. L., Appoo, J. J., Fairman, R. M., Carpenter, J. P., Moser, W. G., Woo, E. Y., Bavaria, J. E. ELSEVIER SCIENCE INC. 2005: 1280–89


    Paraplegia is a recognized complication after endovascular stent repair of descending thoracic aortic aneurysms. A management algorithm employing neurologic assessment, somatosensory evoked potential monitoring, arterial pressure augmentation, and cerebrospinal fluid drainage evolved to decrease the risk of postoperative paraplegia.Patients in thoracic aortic aneurysm stent trials from 1999 to 2004 were analyzed for paraplegic complications. Lower extremity strength was assessed after anesthesia and in the intensive care unit. A loss of lower extremity somatosensory evoked potential or lower extremity strength was treated emergently to maintain a mean arterial pressure 90 mmHg or greater and a cerebrospinal fluid pressure 10 mm Hg or less.Seventy-five patients (male = 49, female = 26, age = 75 +/- 7.4 years) had descending thoracic aortic aneurysms repaired with endovascular stenting. Lumbar cerebrospinal fluid drainage (n = 23) and somatosensory evoked potential monitoring (n = 15) were performed selectively in patients with significant aneurysm extent or with prior abdominal aortic aneurysm repair (n = 17). Spinal cord ischemia occurred in 5 patients (6.6%); two had lower extremity somatosensory evoked potential loss after stent deployment and 4 developed delayed-onset paraplegia. Two had full recovery in response to arterial pressure augmentation alone. Two had full recovery and one had near-complete recovery in response to arterial pressure augmentation and cerebrospinal fluid drainage. Spinal cord ischemia was associated with retroperitoneal bleed (n = 1), prior abdominal aortic aneurysm repair (n = 2), iliac artery injury (n = 1), and atheroembolism (n = 1).Early detection and intervention to augment spinal cord perfusion pressure was effective for decreasing the magnitude of injury or preventing permanent paraplegia from spinal cord ischemia after endovascular stent repair of descending thoracic aortic aneurysm. Routine somatosensory evoked potential monitoring, serial neurologic assessment, arterial pressure augmentation, and cerebrospinal fluid drainage may benefit patients at risk for paraplegia.

    View details for DOI 10.1016/j.athoracsur.2005.04.027

    View details for Web of Science ID 000232442100019

    View details for PubMedID 16181855

  • Active thermoregulation improves outcome of off-pump coronary artery bypass. Asian cardiovascular & thoracic annals Woo, Y. J., Atluri, P., Grand, T. J., Hsu, V. M., Cheung, A. 2005; 13 (2): 157-160


    During off-pump coronary artery bypass grafting, hypothermia increases vasoconstriction, myocardial afterload, coagulopathy and postoperative bleeding. Traditional thermoregulatory techniques do not maintain core body temperature intraoperatively. The efficacy of a commercially available, computer-controlled, water-circulating, dorsal surface, active warming system for thermoregulatory control was evaluated. All patients who underwent non-emergency off-pump coronary bypass grafting by a single surgeon in a 1-year period were studied: the thermoregulation device was used in 50 cases and unavailable for use in 19. The patients who underwent active thermoregulation demonstrated significantly improved core body temperatures compared to the controls: lowest intraoperative, 35.8 degrees C +/- 0.1 degrees C vs. 35.0 degrees C +/- 0.2 degrees C; immediately postoperative, 36.5 degrees C +/- 0.1 degrees C vs. 35.6 degrees C +/- 0.2 degrees C; and 1-hour postoperative, 36.6 degrees C +/- 0.1 degrees C vs. 35.9 degrees C +/- 0.2 degrees C. Thermoregulated patients had significantly reduced 24-hour chest tube drainage (764 +/- 38 vs. 1227 +/- 183 mL), packed red blood cell transfusions (1.4 +/- 0.2 vs. 3.3 +/- 0.7 units), time to extubation (6.8 +/- 0.5 vs. 11.4 +/- 2.3 hours), intensive care unit stay (1.3 +/- 0.1 vs. 2.0 +/- 0.3 days), and hospital stay (4.3 +/- 0.1 vs. 5.1 +/- 0.3 days).

    View details for PubMedID 15905346

  • Safety of lumbar drains in thoracic aortic operations performed with extracorporeal circulation 39th Annual Meeting of the Society-of-Thoracic-Surgeons Cheung, A. T., Pochettino, A., Guvakov, D. V., Weiss, S. J., Shanmugan, S., Bavaria, J. E. ELSEVIER SCIENCE INC. 2003: 1190–96


    The safety of cerebrospinal fluid (CSF) drainage in thoracic aortic surgery using extracorporeal circulation (ECC) with systemic heparinization has not been established.Four hundred thirty-two patients had descending thoracic or thoracoabdominal aortic repair between 1993 and 2002. One hundred sixty-two of those patients (age range, 67 +/- 13 years) had repairs performed with ECC, systemic anticoagulation, and lumbar CSF drainage. Repairs performed without CSF drainage, without ECC, or by stent graft (n = 53) were excluded. The CSF catheters were inserted at L3 to L5. Cerebrospinal fluid was drained to maintain pressures of 10 to 12 mm Hg. In the absence of neurologic deficit or coagulopathy, the catheters were capped at 24 hours and removed at 48 hours. Cerebrospinal fluid drainage was continued beyond 24 hours for delayed onset paraparesis.Cerebrospinal fluid drains were used in 135 thoracoabdominal aortic aneurysms (extent I, n = 63; extent II, n = 25; extent III, n = 39; extent IV, n = 8) and 27 descending thoracic aortic repairs (aneurysm, n = 24; traumatic aortic injury, n = 2; aortic coarctation, n = 1). Partial left heart bypass was used in 132 patients, full cardiopulmonary bypass without deep hypothermic circulatory arrest in 5, and cardiopulmonary bypass with adjunctive deep hypothermic circulatory arrest in 25. Time between catheter insertion and anticoagulation was 153 +/- 60 minutes. Heparin achieved an average maximum activated clotting time of 528 +/- 192 seconds. Average ECC time was 114 +/- 77 minutes. Average deep hypothermic circulatory arrest time was 40 +/- 12 minutes. Mortality was 14.1% (23 of 162), and permanent paraplegia was 4.9% (8 of 162). No epidural or spinal hematoma was observed. Six (3.7%) patients had catheter-related complications (temporary abducens nerve palsy [n = 1]; retained catheter fragments [n = 2]; retained catheter fragment and meningitis [n = 1]; isolated meningitis [n = 1]; and spinal headache [n = 1]).The CSF drainage in thoracic aortic surgery using ECC with full anticoagulation did not result in hemorrhagic complications. The permanent paraplegia rate in this complex patient population consisting of combined distal arch, thoracoabdominal aortic procedures were low, and lumbar CSF catheter-related complications had no permanent sequelae.

    View details for Web of Science ID 000185717900050

    View details for PubMedID 14530010

  • Utility of the neurologic intensive care evaluation (NICE) in detecting neurologic deficit after cardiac operations--a pilot study. Medical science monitor Baker, S., Beauchamp, K., Ballinghoff, J., Escherich, A., Cheung, A. T., Stecker, M. M. 2003; 9 (5): CR151-6


    Neurocognitive changes are common after cardiac operations. The acute post-operative period is a critical time when significant neurologic changes may be detected and appropriate therapy initiated promptly. Formal neuropsychologic testing in this situation however is impractical so other means of early detection are required. The goal of this preliminary study was to determine whether simple, standardized, serial nursing neurologic evaluations using the Neurologic Intensive Care Evaluation (NICE) could be helpful in screening patients for neurologic injury in the immediate post-operative period.Details of the intra-operative and post-operative anesthetic management were obtained during report and nurses subsequently scored acute post-operative patients in the CTSICU using the NICE every half hour for the first five hours. Finally, a chart review was performed to determine the neurologic outcome of the patients.The time to achieve the lower NICE scores which reflect mainly brainstem function was the same whereas the time to achieve NICE scores>4 was prolonged in patients with neurocognitive dysfunction. The effect of intra-operative factors on the times to achieve NICE scores was different for the higher and lower scores. The times to reach NICE scores correlated with outcome variables including the time in ICU and time of intubation.Standardized, serial nursing neurologic assessments of post-operative cardiac patients may be a useful tool for early identification of patients with neurologic injury. They may also provide useful information complementing the data obtained from detailed neuropsychologic testing on the neurologic effects of cardiac operations.

    View details for PubMedID 12761449

  • Interventions for reversing delayed-onset postoperative paraplegia after thoracic aortic reconstruction 38th Annual Meeting of the Society-of-Thoracic-Surgeons Cheung, A. T., Weiss, S. J., McGarvey, M. L., Stecker, M. M., Hogan, M. S., Escherich, A., Bavaria, J. E. ELSEVIER SCIENCE INC. 2002: 413–19


    Delayed postoperative paraplegia is a recognized complication of thoracic (TAA) or thoracoabdominal aortic aneurysm (TAAA) repair. The purpose of this study was to evaluate the effectiveness of interventions to treat delayed-onset paraplegia.Between January 1, 2000 and August 31, 2001, 99 patients underwent surgical repair of TAA, Crawford type I, II, or III TAAA. Standard intraoperative management included distal aortic perfusion and cerebrospinal fluid (CSF) drainage unless contraindicated. Therapeutic interventions to treat delayed paraplegia included lumbar CSF drainage and vasopressor therapy.Three of the 99 patients had paraplegia upon awakening. Delayed-onset paraplegia occurred in 8 patients, 2 of whom had recurrent episodes. In those 8 patients, the initial episode occurred at a median of 21.6 hours (range 6.4 to 110.0 hours) after surgery and the second episode averaged 176 hours after surgery. At the onset of paraplegia, the average mean arterial pressure was 74 mm Hg and CSF pressure was 14 mm Hg. Three of the 8 patients had a functioning CSF catheter at the onset and the other 5 patients had catheters subsequently placed. Therapeutic interventions increased blood pressure to a mean arterial pressure of 95 mm Hg and decreased CSF pressure to 10 mm Hg. Five of the 8 patients with delayed-onset paraplegia made a full neurologic recovery and 3 had partial recovery.Patients with delayed-onset paraplegia had an increased chance of recovery as compared with those patients in whom paraplegia was diagnosed upon emergence from anesthesia. Acute interventions directed to increase spinal cord perfusion by increasing systemic blood pressure and decreasing CSF pressure were effective for the reversal of delayed onset of paraplegia after TAA or TAAA repair, resulting in an overall 3% incidence of permanent paraplegia and 3% incidence of residual paraparesis.

    View details for Web of Science ID 000177320600030

    View details for PubMedID 12173822

  • Reliability of nurses' neurological assessments in the cardiothoracic surgical intensive care unit. American journal of critical care BEAUCHAMP, K., Baker, S., McDaniel, C., Moser, W., Zalman, D. C., Balinghoff, J., Cheung, A. T., Stecker, M. 2001; 10 (5): 298-305


    Alterations in mental status are common among patients in the cardiothoracic surgical intensive care unit. Changes in mental status can be caused by metabolic factors, medications, or brain injury. In this setting, reliable, serial neurological evaluations are critical for assessing the effectiveness of treatment and the need for additional studies.To estimate the reliability of the Rancho Los Amigos Cognitive Scale and the newly developed Neurologic Intensive Care Evaluation as measures of cognitive function in the cardiothoracic surgical intensive care unit.Nurses used 1 of the 2 scales as part of routine neurological assessments of patients in the cardiothoracic surgical intensive care unit. For each test, scores of different observers were correlated and a reliability estimate formed.Interrater reliability was high for both evaluations (Rancho scale, 0.91; Neurologic Intensive Care Evaluation, 0.94). Correlations between the scores of different pairs of observers were also high (mean rho values, 0.84 for the Rancho scale and 0.77 for the Neurologic Intensive Care Evaluation).Both scales are reliable indicators of the neurological state of patients in the cardiothoracic surgical intensive care unit. These scales measure different, although limited, aspects of cognitive function. Each test was simple to administer and did not take more time than the standard nursing neurological examination. Most of the variability in scoring was related to the different degrees of stimulation used by examiners when assessing patients, not to differences in the interpretation of patients' responses.

    View details for PubMedID 11548562

  • Deep hypothermic circulatory arrest: I. Effects of cooling on electroencephalogram and evoked potentials 36th Annual Meeting of the Society-of-Thoracic-Surgeons Stecker, M. M., Cheung, A. T., Pochettino, A., Kent, G. P., Patterson, T., Weiss, S. J., Bavaria, J. E. ELSEVIER SCIENCE INC. 2001: 14–21


    Deep hypothermia is an important cerebral protectant and is critical in procedures requiring circulatory arrest. The purpose of this study was to determine the factors that influence the neurophysiologic changes during cooling before circulatory arrest, in particular the occurrence of electrocerebral silence.In 109 patients undergoing hypothermic circulatory arrest with neurophysiologic monitoring, five electrophysiologic events were selected for detailed study.The mean nasopharyngeal temperature when periodic complexes appeared in the electroencephalogram after cooling was 29.6 degrees C +/- 3 degrees C, electroencephalogram burst-suppression appeared at 24.4 degrees C +/- 4 degrees C, and electrocerebral silence appeared at 17.8 degrees C +/- 4 degrees C. The N20-P22 complex of the somatosensory evoked response disappeared at 21.4 degrees C +/- 4 degrees C, and the somatosensory evoked response N13 wave disappeared at 17.3 degrees C +/- 4 degrees C. The temperatures of these various events were not significantly affected by any patient-specific or surgical variables, although the time to cool to electrocerebral silence was prolonged by high hemoglobin concentrations, low arterial partial pressure of carbon dioxide, and by slow cooling rates. Only 60% of patients demonstrated electrocerebral silence by either a nasopharyngeal temperature of 18 degrees C or a cooling time of 30 minutes.With the high degree of interpatient variability in these neurophysiologic measures, the only absolute predictors of electrocerebral silence were nasopharyngeal temperature below 12.5 degrees C and cooling longer than 50 minutes.

    View details for Web of Science ID 000166457600003

    View details for PubMedID 11216734

  • Deep hypothermic circulatory arrest: II. Changes in electroencephalogram and evoked potentials during rewarming 36th Annual Meeting of the Society-of-Thoracic-Surgeons Stecker, M. M., Cheung, A. T., Pochettino, A., Kent, G. P., Patterson, T., Weiss, S. J., Bavaria, J. E. ELSEVIER SCIENCE INC. 2001: 22–28


    Electrophysiologic studies during rewarming after deep hypothermic circulatory arrest probe the state of the brain during this critical period and may provide insight into the neurological effects of circulatory arrest and the neurologic outcome.Electroencephalogram (EEG) and evoked potentials were monitored during rewarming in 109 patients undergoing aortic surgery with hypothermic circulatory arrest.The sequence of neurophysiologic events during rewarming did not mirror the events during cooling. The evoked potentials recovered first followed by EEG burst-suppression and then continuous EEG. The time to recovery of the evoked potentials N20-P22 complex was significantly correlated with the time of circulatory arrest even in patients without postoperative neurologic deficits (r = 0.37, (p = 0.002). The nasopharyngeal temperatures at which continuous EEG activity and the N20-P22 complex returned were strongly correlated (r = 0.44, p = 0.0002; r = 0.41, p = 0.00003) with postoperative neurologic impairment. Specifically, the relative risk for postoperative neurologic impairment increased by a factor of 1.56 (95% CI 1.1 to 2.2) for every degree increase in temperature at which the EEG first became continuous.No trend toward shortened recovery times or improved neurologic outcome was noted with lower temperatures at circulatory arrest, indicating that the process of cooling to electrocerebral silence produced a relatively uniform degree of cerebral protection, independent of the actual nasopharyngeal temperature.

    View details for Web of Science ID 000166457600004

    View details for PubMedID 11216751

  • Postoperative neurologic assessment and management of the cardiac surgical patient. Seminars in thoracic and cardiovascular surgery Floyd, T. F., Cheung, A. T., Stecker, M. M. 2000; 12 (4): 337-348


    The neurologic evaluation of patients in the immediate postoperative period and postanesthetic state is unique and challenging. Neurologic assessment is complicated by the lingering residual effects of anesthetics as well as by the effects of narcotic analgesics, anxiolytics, and muscle relaxants, especially in ventilated patients. In this review we examine the suspected causes, clinical manifestations, diagnostic options, and intervention schemes for the common neurologic syndromes seen after cardiac operations.

    View details for PubMedID 11154729

  • Nicardipine intravenous bolus dosing for acutely decreasing arterial blood pressure during general anesthesia for cardiac operations: Pharmacokinetics, pharmacodynamics, and associated effects on left ventricular function Annual Meeting of the American-Society-of-Anesthesiologists Cheung, A. T., Guvakov, D. V., Weiss, S. J., Savino, J. S., Salgo, I. S., Meng, Q. C. LIPPINCOTT WILLIAMS & WILKINS. 1999: 1116–23


    The objective of this study was to evaluate the efficacy of nicardipine, a dihydropyridine calcium channel antagonist, administered as an IV bolus dose to acutely decrease arterial pressure in anesthetized cardiac surgical patients. We performed a double-blind, randomized, self-controlled, dose-ranging study in 40 adult cardiac surgical patients to determine the pharmacokinetics and pharmacodynamics of nicardipine 0.25 mg, 0.50 mg, 1.00 mg, and 2.00 mg administered as an IV bolus. Transesophageal echocardiography was used to assess left ventricular preload, afterload, and global systolic function. Plasma nicardipine concentration was measured using high-performance liquid chromatography. Nicardipine selectively decreased arterial pressure in a dose-dependent manner with a maximum response within 100 s and recovery to half the maximum response within 3-7 min without associated changes in heart rate. The decreases in arterial pressure were associated with only small decreases in left ventricular end-systolic wall stress and small increases in global left ventricular systolic function without changes in left ventricular end-diastolic cavity area or cardiac output. The time course for nicardipine bolus was consistent with a two-compartment pharmacokinetic model with rapid redistribution from a small central compartment.Nicardipine was effective for selectively decreasing arterial blood pressure acutely, but had no effects on ventricular preload or cardiac output. The absence of dose-dependent changes in cardiac output, left ventricular systolic performance, and left ventricular afterload despite significant decreases in arterial pressure suggested that nicardipine had a small negative inotropic action.

    View details for Web of Science ID 000083498200008

    View details for PubMedID 10553821

  • ASE/SCA guidelines for performing a comprehensive intraoperative multiplane transesophageal echocardiography examination: Recommendations of the American Society of Echocardiography Council for Intraoperative Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for Certification in Perioperative Transesophageal Echocardiography ANESTHESIA AND ANALGESIA Shanewise, J. S., Cheung, A. T., ARONSON, S., Stewart, W. J., Weiss, R. L., Mark, J. B., Savage, R. M., Sears-Rogan, P., Mathew, J. P., Quinones, M. A., Cahalan, M. K., Savino, J. S. 1999; 89 (4): 870-884

    View details for Web of Science ID 000082827700010

    View details for PubMedID 10512257

  • Oxygen delivery during retrograde cerebral perfusion in humans ANESTHESIA AND ANALGESIA Cheung, A. T., Bavaria, J. E., Pochettino, A., Weiss, S. J., Barclay, D. K., Stecker, M. M. 1999; 88 (1): 8-15


    Retrograde cerebral perfusion (RCP) potentially delivers metabolic substrate to the brain during surgery using hypothermic circulatory arrest (HCA). Serial measurements of O2 extraction ratio (OER), PCO2, and pH from the RCP inflow and outflow were used to determine the time course for O2 delivery in 28 adults undergoing aortic reconstruction using HCA with RCP. HCA was instituted after systemic cooling on cardiopulmonary bypass for 3 min after the electroencephalogram became isoelectric. RCP with oxygenated blood at 10 degrees C was administered at an internal jugular venous pressure of 20-25 mm Hg. Serial analyses of blood oxygen, carbon dioxide, pH, and hemoglobin concentration were made in samples from the RCP inflow (superior vena cava) and outflow (innominate and left carotid arteries) at different times after institution of RCP. Nineteen patients had no strokes, five patients had preoperative strokes, and four patients had intraoperative strokes. In the group of patients without strokes, HCA with RCP was initiated at a mean nasopharyngeal temperature of 14.3 degrees C with mean RCP flow rate of 220 mL/min, which lasted 19-70 min. OER increased over time to a maximal detected value of 0.66 and increased to 0.5 of its maximal detected value 15 min after initiation of HCA. The RCP inflow-outflow gradient for PCO2 (slope 0.73 mm Hg/min; P < 0.001) and pH (slope 0.007 U/min; P < 0.001) changed linearly over time after initiation of HCA. In the group of patients with preoperative or intraoperative strokes, the OER and the RCP inflow-outflow gradient for PCO2 changed significantly more slowly over time after HCA compared with the group of patients without strokes. During RCP, continued CO2 production and increased O2 extraction over time across the cerebral vascular bed suggest the presence of viable, but possibly ischemic tissue. Reduced cerebral metabolism in infarcted brain regions may explain the decreased rate of O2 extraction during RCP in patients with strokes.Examining the time course of oxygen extraction, carbon dioxide production, and pH changes from the retrograde cerebral perfusate provided a means to assess metabolic activity during hypothermic circulatory arrest.

    View details for Web of Science ID 000077901200002

    View details for PubMedID 9895058

  • Detection of stroke during cardiac operations with somatosensory evoked responses JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Stecker, M. M., Cheung, A. T., Patterson, T., Savino, J. S., Weiss, S. J., Richards, R. M., Bavaria, J. E., Gardner, T. J. 1996; 112 (4): 962-972


    The objectives of this study were to determine if monitoring of intraoperative somatosensory evoked potentials could be used to detect stroke during cardiac operations and to establish indicators of cerebral ischemia based on changes in these potentials.Twenty-five patients undergoing cardiac operations underwent preoperative and postoperative neurologic examinations as well as intraoperative recording of somatosensory evoked potentials. Detailed analysis of the waveforms of these potentials was performed.Two of the 25 patients had intraoperative strokes. These patients and only these patients had changes in their somatosensory evoked potentials during the operation suggesting cerebral ischemia. The unilateral disappearance of the cortical somatosensory evoked potential waves correlated significantly with the clinical outcome of stroke (p < 0.004). Ischemic changes were detected in real time and were related to the removal of the aortic crossclamp in one patient and to the initiation of cardiopulmonary bypass in the other.Somatosensory evoked potentials can detect intraoperative stroke during cardiac operations. Acute, unilateral decreases in amplitude of the cortical potential are more useful than changes in latency in detecting intraoperative stroke.

    View details for Web of Science ID A1996VW27500013

    View details for PubMedID 8873722

  • Beat-to-beat augmentation of left ventricular function by intraaortic counterpulsation American-Society-of-Anesthesiologists Annual Meeting Cheung, A. T., Savino, J., Weiss, S. J. LIPPINCOTT-RAVEN PUBL. 1996: 545–54


    Measuring the effects of intraaortic balloon counterpulsation (IABP) in single cardiac beats may permit an improved understanding of the physiologic mechanisms by which IABP improves the circulation. The objective of the study was to use trans- esophageal echocardiography in combination with hemodynamic measurements to test the hypothesis that IABP improves global left ventricular systolic function selectively in the IABP-augmented cardiac beats by acutely decreasing left ventricular afterload.Twenty-seven studies in which the IABP-to-R wave trigger ratio was serially changed from 1:1, 1:2, 1:4, 0:1 (IABP off) and back to 1:1 were performed in 20 anesthetized cardiac surgical patients during IABP support. Left ventricular short-axis end-diastolic cross-sectional area, end-systolic area, mean end-systolic wall thickness, and ejection time were measured by transesophageal echocardiography at the midpapillary muscle level. Aortic pressure was measured simultaneously from the central lumen of the intraaortic balloon catheter. These measurements were used to calculate the fractional area change, end-systolic meridional wall stress, and heart rate-corrected velocity of circumferential fiber shortening. The echocardiographic and hemodynamic parameters of left ventricular preload, afterload, and systolic function immediately after balloon deflation (IABP-augmented cardiac beats) were compared to the parameters measured during nonaugmented cardiac beats to determine the beat-to-beat effects of IABP on left ventricular function.IABP-augmented cardiac beats had a decreased systolic arterial pressure and end-systolic meridional wall stress and increased diastolic blood pressure, fractional area change, and velocity of circumferential fiber shortening compared to nonaugmented cardiac beats. IABP did not cause significant beat-to-beat changes in heart rate, pulmonary artery diastolic pressure, or central venous pressure. The improvement in left ventricular systolic function associated with IABP-augmented cardiac beats correlated with the decrease in end-systolic meridional wall stress for that cardiac beat.Beat-to-beat echocardiographic and hemodynamic measurements performed in anesthetized cardiac surgical patients during IABP support demonstrated improved left ventricular systolic function and decreased left ventricular systolic wall stress in the cardiac beats immediately after balloon deflation. The relationship between left ventricular systolic function and left ventricular systolic wall stress during IABP support suggests that afterload reduction was an important mechanism by which IABP instantaneously improved circulatory function in anesthetized cardiac surgical patients.

    View details for Web of Science ID A1996UA37700010

    View details for PubMedID 8659782

  • Fatal paradoxical cerebral embolization during bilateral knee arthroplasty ANESTHESIOLOGY Weiss, S. J., Cheung, A. T., Stecker, M. M., Garino, J. P., Hughes, J. E., Murphy, F. L. 1996; 84 (3): 721-723

    View details for Web of Science ID A1996UA37700029

    View details for PubMedID 8659801

  • Calcium blockage in pulmonary hypertension and hypoxic vasoconstriction. New horizons (Baltimore, Md.) NEELY, C. F., Stein, R., Matot, I., Batra, V., Cheung, A. 1996; 4 (1): 99-106


    Both extracellular and intracellular calcium (Ca2+) play important roles in hypoxic pulmonary vasoconstriction (HPV) and the vasoconstrictor responses to endogenous pulmonary vasoconstrictor substances, as evidenced by the effect of calcium-channel blockers on these vasoconstrictor responses and the measurement of changes in Ca2+ flux or intracellular Ca2+ concentrations in isolated cells. The more vasoselective the calcium-channel blocker, the greater its effect on pulmonary vasoconstriction. However, these drugs are not selective for the pulmonary vascular bed and are not as potent as pulmonary vasodilators when compared with other vasodilator drugs, including prostaglandin E1, isoproterenol, prostacyclin, or nitroglycerin. Moreover, the primary effect of vasoselective calcium-channel blockers on pulmonary vascular resistance is secondary to the effects of these agents on systemic vascular resistance and cardiac output. Although there is improvement in oxygen delivery, exercise tolerance, and survival in patients with primary pulmonary hypertension who respond to calcium-channel blockers, the response of individual patients to these drugs is difficult to predict because the extent of reversible versus irreversible changes in the pulmonary vasculature is not known. The use of these drugs in patients with chronic hypoxia-induced pulmonary vasoconstriction may be associated with a worsening of ventilation-perfusion mismatching secondary to inhibition of HPV.

    View details for PubMedID 8689279


    View details for Web of Science ID A1995RH99900026

    View details for PubMedID 7605001



    Transesophageal echocardiography (TEE) is used to diagnose hypovolemia despite the lack of validation studies. The objective was to determine the effects of acute graded hypovolemia on TEE and conventional hemodynamic determinants of left ventricular (LV) preload in anesthetized patients with normal and abnormal LV function.Determinants of LV preload derived from TEE and hemodynamic monitoring were measured serially in 35 anesthetized cardiac surgical patients without valvular heart disease. Patients were stratified into two groups: those with normal LV function (group 1, n = 17) and those with LV wall motion abnormalities (group 2, n = 13). Patients in groups 1 and 2 were subjected to graded hypovolemia produced by collecting 6 aliquots of blood, each equal to 2.5% of their estimated blood volume (EBV). A third group of patients (group 3, n = 5), not subjected to graded hypovolemia, were studied to test for time-dependent changes.Group 2 had a significantly greater baseline (mean +/- SD) pulmonary artery occlusion pressure (17 +/- 6 vs. 11 +/- 6 mmHg), LV end-diastolic area (23 +/- 5 vs. 18 +/- 4 cm2), LV end-diastolic wall stress (23 +/- 10 vs. 14 +/- 6 x 10(3), and smaller fractional area change (35 +/- 13 vs. 59 +/- 7%). In groups 1 and 2, the LV end-diastolic area, pulmonary artery occlusion pressure, and LV end-diastolic wall stress decreased linearly in response to blood loss in the range of 0-15% of the EBV. No significant changes in the measured parameters occurred in group 3. A significant decrease in the central venous pressure, pulmonary artery occlusion pressure, and LV end-diastolic area was detected in response to a 2.5% EBV deficit (approximately 1.75 in groups 1 and 2. The mean change in LV end-diastolic area (0.3 cm2/1.0% EBV deficit) in response to equivalent EBV deficits was the same in groups 1 and 2. In contrast, the mean change in cardiac output and LV end-diastolic wall stress was less in group 2 despite a greater decrease in pulmonary artery occlusion pressure. Compared to group 1, a greater EBV deficit (7.5% to 12.5% vs. 2.5% to 5%) was required in group 2 to cause a significant decrease in the cardiac output, stroke volume, mixed venous oxygen saturation, and LV end-diastolic wall stress.TEE and hemodynamic determinants of LV preload detected changes in LV function caused by acute blood loss. Acute blood loss caused directional changes in LV end-diastolic area, pulmonary artery occlusion pressure, and LV end-diastolic wall stress even in patients with LV wall motion abnormalities. Changes in LV end-diastolic wall stress, derived from both TEE and hemodynamic measurements corresponded to changes in cardiac output, stroke volume, and mixed venous oxygen saturation that occurred during acute blood loss.

    View details for Web of Science ID A1994PA47900014

    View details for PubMedID 8053588

  • Oropharyngeal injury after transesophageal echocardiography. Journal of cardiothoracic and vascular anesthesia Savino, J. S., Hanson, C. W., Bigelow, D. C., Cheung, A. T., Weiss, S. J. 1994; 8 (1): 76-78

    View details for PubMedID 8167291