Professor - Med Center Line, Cardiothoracic Surgery
New technologies in the area of catheters, clamps, and, visualization devices for aid in cardiac surgery; distribution of, cardioplegia, both anterograde and retrograde as determined by, techniques in technetium pyro-phosphate scans; glucose insulin, potassium as an adjunct in cardiac surgery.
The purpose of the study is to investigate the safety and efficacy of transcatheter aortic valve implantation (TAVI) in patients with severe, symptomatic Aortic Stenosis (AS) at intermediate surgical risk by randomizing patients to either Surgical Aortic Valve Replacement (SAVR) or TAVI with the Medtronic CoreValve® System. Single Arm: The purpose of this trial is to evaluate the safety and effectiveness of transcatheter aortic valve implementation (TAVI) in patients with sever symptomatic Aortic Stenosis (AS) at intermediate surgical risk with TAVI. This is a non-randomized phase of the pivotal clinical trial.
This will be a multi-center, proof of concept phase 0 study to assess the suppression of p-AKT in Vestibular Schwannoma (VS) and meningiomas by AR-42 in adult patients undergoing tumor resection. AR-42 is a small molecule which crosses the blood brain barrier (BBB) in rodents, but the investigators are not certain yet if it will penetrate human VS. Meningiomas are outside the BBB, but seem to be unusually resistant to all current medical treatments. The primary endpoint of the bioactivity of suppression of p-AKT by AR-42 was selected as drug activity seems more informative than bioavailability. Our preclinical data and others have shown dose dependent suppression of p-AKT by AR-42 in both VS and meningiomas.
Stanford is currently not accepting patients for this trial.
The purpose of this study was to characterize health status outcomes after transcatheter aortic valve replacement (TAVR) with a self-expanding bioprosthesis among patients at extreme surgical risk and to identify pre-procedural patient characteristics associated with a poor outcome.For many patients considering TAVR, improvement in quality of life may be of even greater importance than prolonged survival.Patients with severe, symptomatic aortic stenosis who were considered to be at prohibitive risk for surgical aortic valve replacement were enrolled in the single-arm CoreValve U.S. Extreme Risk Study. Health status was assessed at baseline and at 1, 6, and 12 months after TAVR using the Kansas City Cardiomyopathy Questionnaire (KCCQ), the Short Form-12, and the EuroQol-5D. The overall summary scale of the KCCQ (range 0 to 100; higher scores = better health) was the primary health status outcome. A poor outcome after TAVR was defined as death, a KCCQ overall summary score (OS) <45, or a decline in KCCQ-OS of 10 points at 6-month follow-up.A total of 471 patients underwent TAVR via the transfemoral approach, of whom 436 (93%) completed the baseline health status survey. All health status measures demonstrated considerable impairment at baseline. After TAVR, there was substantial improvement in both disease-specific and generic health status measures, with an increase in the KCCQ-OS of 23.9 points (95% confidence interval [CI]: 20.3 to 27.5 points) at 1 month, 27.4 points (95% CI: 24.2 to 30.6 points) at 6 months, 27.4 points (95% CI: 24.1 to 30.8 points) at 12 months, along with substantial increases in Short Form-12 scores and EuroQol-5D utilities (all p < 0.003 compared with baseline). Nonetheless, 39% of patients had a poor outcome after TAVR. Baseline factors independently associated with poor outcome included wheelchair dependency, lower mean aortic valve gradient, prior coronary artery bypass grafting, oxygen dependency, very high predicted mortality with surgical aortic valve replacement, and low serum albumin.Among patients with severe aortic stenosis, TAVR with a self-expanding bioprosthesis resulted in substantial improvements in both disease-specific and generic health-related quality of life, but there remained a large minority of patients who died or had very poor quality of life despite TAVR. Predictive models based on a combination of clinical factors as well as disability and frailty may provide insight into the optimal patient population for whom TAVR is beneficial. (Safety and Efficacy Study of the Medtronic CoreValve® System in the Treatment of Symptomatic Severe Aortic Stenosis in High Risk and Very High Risk Subjects Who Need Aortic Valve Replacement; NCT01240902).
View details for DOI 10.1016/j.jcin.2014.08.016
View details for PubMedID 25700755
"Field dependence" is used in cognitive psychology to describe an individual's tendency to be visually distracted by the surrounding environment. Notwithstanding the role of field dependence in contexts in which spatial judgment is important, such as piloting an aircraft, to date, studies linking field dependence to surgical skills have been limited. We evaluated whether field dependence correlates with an ability to anticipate appropriate needle angles in a simulated setting.Trainees underwent field dependence testing and then participated in a surgical skills exercise. Correlations between field dependence and surgical skill were computed. Specifically, cardiothoracic surgery residents (n = 11) took a battery of cognitive examinations to assess general reasoning and visuospatial judgment. Two written tests, the Rod and Frame test and the Judgment of Line Orientation test, measured the degree of field dependence. The subjects then underwent surgical skills testing. Using a standard needle driver, the participants placed curved needles into a cylindrical silicone mitral valve model with 10 premarked needle entry and exit sites. The components assessed included the ability to load a needle on driver at the appropriate angle.The test results showed a parametric distribution, with internal cognitive testing controls demonstrating valid testing techniques and methods. Performance on the cognitive tests measuring spatial judgment and field dependence correlated significantly with skill at determining the appropriate needle angle load in an inverse fashion (Judgment of Line Orientation test, r = 0.61, P < .05; Rod and Frame test, r = -0.52, P = .05), suggesting that residents who were not distracted by surrounding objects performed better. Performance on the cognitive examinations did not correlate with resident training level.Although our study was of a small cohort, the findings suggest that individuals described as field independent (not easily distracted by external visual cues) might possess improved ability to determine appropriate needle angle loads compared with field-dependent individuals. Additional studies examining the role field dependence might play in the acquisition and execution of surgical tasks are warranted.
View details for DOI 10.1016/j.jtcvs.2014.05.008
View details for PubMedID 24928261
The US Food and Drug Administration recently approved a transcatheter aortic valve for patients for whom open heart surgery is prohibitively risky.A multidisciplinary heart valve team partnered with administration to launch a transcatheter aortic valve replacement (TAVR) program. Clinical registries were used to show robust valve caseloads and outcomes at our Veterans Affairs (VA) facility and to project future volumes. A TAVR business plan was approved by the VA leadership as part of a multiphase project to upgrade and expand our surgical facilities.The heart valve team completed a training program that included simulations and visits to established TAVR centers. Patients were evaluated and screened through a streamlined process, and the program was initiated successfully.Establishing a TAVR program at a VA facility requires a multidisciplinary team with experience in heart valve and endovascular therapies and a supportive administration willing to invest in a sophisticated infrastructure.
View details for DOI 10.1016/j.amjsurg.2012.07.017
View details for Web of Science ID 000311734000022
View details for PubMedID 22921150
Limited exposure and visualization and technical complexity have affected resident training in mitral valve surgery. We propose simulation-based learning to improve skill acquisition in mitral valve surgery.After reviewing instructional video recordings of mitral annuloplasty in porcine and plastic models, 11 residents (6 integrated and 5 traditional) performed porcine model mitral annuloplasty. Video-recorded performance was reviewed by attending surgeon providing audio formative feedback superimposed on video recordings; recordings were returned to residents for review. After 3-week practice with plastic model, residents repeated porcine model mitral annuloplasty. Performance assessments initially (prefeedback) and at 3 weeks (postfeedback) were based on review of video recordings on 5-point rating scale (5, good; 3, average; 1, poor) of 11 components. Ratings were averaged for composite score.Time to completion improved from mean 31 ± 9 minutes to 25 ± 6 minutes after 3-week practice (P = .03). At 3 weeks, improvement in technical components was achieved by all residents, with prefeedback scores varying from 2.4 ± 0.6 for needle angles to 3.0 ± 0.5 for depth of bites and postfeedback scores of 3.1 ± 0.8 for tissue handling to 3.6 ± 0.8 for suture management and tension (P ≤ .001). Interrater reliability was greater than 0.8. In this sample, composite scores of first-year integrated and traditional residents were lower than those of senior level residents; comparatively, third-year integrated residents demonstrated good technical proficiency.Simulation-based learning with formative feedback results in overall improved performance of simulated mitral annuloplasty. In complex surgical procedures, simulation may provide necessary early graduated training and practice. Importantly, a "passing" grade can be established for proficiency-based advancement.
View details for DOI 10.1016/j.jtcvs.2010.08.059
View details for Web of Science ID 000285407500021
View details for PubMedID 21074189
Cardiac surgery trainees might benefit from simulation training in coronary anastomosis and more advanced procedures. We evaluated distributed practice using a portable task station and experience on a beating-heart model in training coronary anastomosis.Eight cardiothoracic surgery residents performed 2 end-to-side anastomoses with the task station, followed by 2 end-to-side anastomoses to the left anterior descending artery by using the beating-heart model at 70 beats/min. Residents took home the task station, recording practice times. At 1 week, residents performed 2 anastomoses on the task station and 2 anastomoses on the beating-heart model. Performances of the anastomosis were timed and reviewed.Times to completion for anastomosis on the task station decreased 20% after 1 week of practice (351 +/- 111 to 281 +/- 53 seconds, P = .07), with 2 residents showing no improvement. Times to completion for beating-heart anastomosis decreased 15% at 1 week (426 +/- 115 to 362 +/- 94 seconds, P = .03), with 2 residents demonstrating no improvement. Home practice time (90-540 minutes) did not correlate with the degree of improvement. Performance rating scores showed an improvement in all components. Eighty-eight percent of residents agreed that the task station is a good method of training, and 100% agreed that the beating-heart model is a good method of training.In general, distributed practice with the task station resulted in improvement in the ability to perform an anastomosis, as assessed by times to completion and performance ratings, not only with the task station but also with the beating-heart model. Not all residents improved, which is consistent with a "ceiling effect" with the simulator and a "plateau effect" with the trainee. Simulation can be useful in preparing residents for coronary anastomosis and can provide an opportunity to identify the need and methods for remediation.
View details for DOI 10.1016/j.jtcvs.2008.08.016
View details for PubMedID 19114195
Congenital coronary anomalies can be found in up to 1% of patients undergoing angiography. The most severe of these lesions become symptomatic in early childhood, while others can remain without consequence. However, while being silent in the early decades of life, these asymptomatic anomalies can contribute to the presentation of acquired heart disease and can themselves become clinically significant. We describe the clinical course of two patients with congenital coronary artery anomalies presenting beyond the fifth decade of life with concurrent acquired heart disease.
View details for DOI 10.1111/j.1540-8191.2008.00645.x
View details for Web of Science ID 000260499400043
View details for PubMedID 19017010
Atrial septal defects are among the most common congenital anomalies requiring surgical repair. Thrombus formation after patch-based repair is a recognized complication, usually manifested by an embolic event. However, thromboembolic complications after primary repair of atrial septal defects are exceedingly rare. We present a 38-year-old woman found to have a right atrial mass diagnosed as a myxoma by echocardiography and magnetic resonance imaging 3 years after primary atrial septal defect repair. However, final pathology revealed an organized thrombus. A review of the literature and clinical management of postoperative atrial thrombi are discussed.
View details for DOI 10.1016/j.athoracsur.2007.05.065
View details for Web of Science ID 000250782500050
View details for PubMedID 17954102
We evaluated an endobronchial valve device in the treatment of surgically created air leak or pneumothorax by eliminating antegrade flow.Six sheep underwent general anesthesia with positive pressure ventilation and left thoracotomy. After division of the mediastinal pleura, the contralateral cranial lobe was identified and a 2.5 cmx1.5 cm laceration created with resultant air leak. Using bronchoscopy, we deployed a valve device in the bronchus of the injured segment. Chest drainage tube was placed and the thoracotomy closed. At 1 week (n=3) and 4 weeks (n=3), the animals underwent general anesthesia, bronchoscopy and right thoracotomy.All animals survived the procedure. Bronchoscopic valve device placement in the segmental bronchus resolved the air leak immediately. After closure of thoracotomy, the chest tube demonstrated minimal drainage with no air leak. At 1 and 4 weeks, bronchoscopy showed no change in device location, and the treated segments were atelectatic with fibrous scar at the injured site.Collapse of a selected lung segment with resolution of air leak can be achieved using bronchoscopically implanted valve device. The valve device may facilitate treatment of patients with post-surgical or post-traumatic persistent air leak.
View details for DOI 10.1016/j.rmed.2005.11.011.
View details for Web of Science ID 000239219000014
View details for PubMedID 16376535
A 43-year-old woman underwent mitral valve replacement for severe mitral regurgitation nine years after orthotopic heart transplant. Histopathology showed chronic rejection of the mitral valve with lymphocytic infiltrates. The patient is well at one year follow-up. This report describes an identified case of chronic mitral valve rejection requiring valve replacement.
View details for DOI 10.1016/j.athoracsur.2004.06.036
View details for Web of Science ID 000232970500054
View details for PubMedID 16242482
We report a 55-year-old man, the recipient of a cardiac allograft for ischemic cardiomyopathy 9 years earlier, who presented with progressive aortic root dilation, worsening aortic insufficiency, and an incidentally discovered chronic type A aortic dissection limited to the donor aorta. The patient was taken to the operating room, and the aortic dissection successfully repaired using standard reoperative techniques. This is the sixth case reported in the literature, and only the fourth survivor. To our knowledge, this case represents the first successful repair, of a limited aortic dissection of the donor aorta postcardiac transplantation, using a composite valve graft and modified-Cabrol coronary reconstruction.
View details for DOI 10.1111/j.1540-8191.2005.200467.x
View details for Web of Science ID 000232380400010
View details for PubMedID 16153277
Surgical edge-to-edge repair has been used in the treatment of mitral regurgitation. We evaluated the ability of a catheter-delivered clip (Evalve, Inc) to achieve edge-to-edge mitral valve approximation without cardiopulmonary bypass and the healing response of this technique.Twenty-one pigs underwent general anesthesia and left thoracotomy. A 10F flexible delivery catheter with a clip was placed into the left atrium. With echocardiographic and fluoroscopic guidance, the clip grasped and approximated the mid portion of the anterior and posterior leaflets. After a double orifice had been confirmed, the clip was detached and the catheter withdrawn. All animals survived and had successful clip placement. Three animals were euthanized at 4 weeks, 9 at 12 weeks, 1 at 17 weeks, 7 at 24 weeks, and 1 at 52 weeks. The clip was well positioned, with leaflet approximation in all animals except 1, in which the clip separated from the posterior leaflet at 4 weeks without affecting valve function. The clip was modified and implanted in 4 pigs; all were intact at 12 to 24 weeks. Scanning electron microscopy showed clip encapsulation with complete endothelialization. Mitral stenosis and thromboembolism did not develop. Two animals developed endocarditis (1 at 12 weeks and 1 at 17 weeks). Progressive healing occurred in all other animals.Edge-to-edge mitral valve approximation can be successfully and reliably achieved with a catheter-delivered clip without cardiopulmonary bypass, resulting in durable healing. The success of this device supports the development of a percutaneous catheter-based system for mitral valve repair.
View details for DOI 10.1161/01.CIR.0000139855.12616.15
View details for Web of Science ID 000223492700016
View details for PubMedID 15302782
View details for Web of Science ID 000223999000001
Abstract We report a case of a patient who sustained superior vena cava perforation just proximal to the innominate-caval confluence during pacemaker implantation. Because this complication was recognized early and the dilator was left in place, the patient remained hemodynamically stable and successfully underwent a videoscopically assisted repair of the superior vena caval perforation through a limited thoracotomy incision.
View details for PubMedID 14980836
Intraabdominal anastomotic pseudoaneurysms continue to be a late complication of aortic reconstructive procedures. Early surgical repair is critical but is associated with high operative mortality rates. We present a patient who was diagnosed with a distal anastomotic pseudoaneurysm 13 months after transabdominal repair of a symptomatic abdominal aortic aneurysm. Because of the poor operative risk, the patient was considered for a less invasive approach and underwent coil embolization of the abdominal aortic anastomotic pseudoaneurysm. The patient remains without recurrence of pseudoaneurysm 3.5 years later.
View details for DOI 10.1067/mva.2002.121744
View details for Web of Science ID 000175366300033
View details for PubMedID 11932686
Left ventricular-right atrial (LV-RA) communications are rare intracardiac defects, often congenital in nature and clinically apparent during childhood. Acquired LV-RA shunts are encountered occasionally in the adult population as a result of a defect in the upper portion of the membranous ventricular septum. We describe the clinical and echocardiographic features of an elderly patient with an acquired LV-RA communication in the setting of an aortic composite valve graft and endocarditis. We also review the anatomical features and hemodynamic consequences of such defects.
View details for Web of Science ID 000174467600010
View details for PubMedID 11884258
Different viewing conditions (two- and three-dimensional National Television Standard Committee [2D-NTSC and 3D-NTSC] and two-dimensional high-definition television [2D-HDTV]) on telemanipulator performance were evaluated.Six taskes were performed by 15 endoscopic surgeons using the daVinci telemanipulation system. Performance time and errors were measured. Encoder data from the system were used for kinematic analysis of motion. A self-evaluation questionnaire regarding performance under various viewing conditions was obtained.Resolution was better with 2D-HDTV. The estimate of relative distance was not influenced by the different visualization systems. Motor skill tasks were performed faster with binocular vision (3D-NTSC) than with monocular vision (2D-NTSC, 2D-HDTV). For both 2D settings, the deceleration phase of motion was prolonged (p < 0.05 vs 3D). Peak velocity was reduced with 2D-HDTV as compared with 3D-NTSC (p = 0.01). The surgeons tended to favor the 3D system despite their use of 2D systems in their own practice.Three-dimensional vision enhances telemanipulator performance as compared with a 2D system at the same or higher level of resolution. Because it allows faster and more precise movement, future surgical systems should focus on 3D visualization.
View details for Web of Science ID 000171950700005
View details for PubMedID 11727134
The indications for tissue valves in the aortic and mitral positions are becoming better defined with advances in valve design, valve preservation, and management of reoperations. Although some patients who require cardiac valve replacement clearly benefit more from one type of valve than from another, not infrequently one encounters a patient who is in the "gray zone," where the optimal choice is difficult. At present, bioprostheses for the diseased aortic valve include stented porcine and pericardial valves, stentless porcine valves, aortic homograft, and pulmonary autograft. For patients with mitral valve disease, options for tissue valve replacement are a stented porcine or pericardial prosthesis. Generally, factors to consider in choosing the appropriate valve substitute include the patient's age, expected life expectancy, coexisting medical problems, lifestyle, and socioeconomics; the etiology of the valve disease, annular size, and physician and patient preference are also relevant. Despite the known finite durability of tissue valves, which is the main limitation in their use, the long-term results have been satisfactory, particularly in older patients, patients with a limited life expectancy, and those undergoing valve replacement in the aortic position. Distillation of available information and ongoing communication between the surgeon and the cardiologist will enable us to assist the patient in choosing the best valve substitute.
View details for Web of Science ID 000167419100009
View details for PubMedID 11224645
Telemanipulation systems have enabled coronary revascularization on the arrested heart. The purpose of this study was to develop a technique for computer-enhanced endoscopic coronary artery bypass grafting on the beating heart.The operation was performed using the daVinci telemanipulation system. Through three ports, the left internal thoracic artery was harvested in 10 mongrel dogs (30 to 35 kg) using single right-lung ventilation and CO2 insufflation. Through a fourth port an articulating stabilizer, manipulated from a second surgical console, was inserted to stabilize the heart. The left anterior descending artery was snared using silicone elastomer slings anchored in the stabilizer cleats and the graft to coronary artery anastomosis was performed.In 7 of 10 dogs, total endoscopic beating heart bypass grafting, cardiac stabilization, arteriotomy, and arterial anastomosis were performed using computer-enhanced technology. Endoscopic stabilization and temporary left anterior descending artery occlusion were well tolerated. All grafts were patent although minor strictures were found in 2. In 3 dogs, the procedure could not be completed (1 ventricular arrhythmia, 1 left atrial laceration, and 1 right ventricular outflow tract compression).Endoscopic beating heart coronary artery bypass grafting is possible in a canine model using a computer-enhanced instrumentation system and articulating stabilization.
View details for Web of Science ID 000166022900059
View details for PubMedID 11156115
A new method of endoscopic ultrasonography during endoscopic bypass grafting is described. Using a 7.5 MHz ultrasonic catheter (AcuNav, Acuson, Mountain View, CA) that was introduced through a 5mm port and manipulated by robotically enhanced endoscopic instruments, detection of the internal thoracic artery (ITA) and the left anterior descending (LAD) artery was possible through layers of fat and muscle in a canine model.
View details for Web of Science ID 000166577900014
View details for PubMedID 11178297
For minimally invasive cardiac operations to be widely applicable, the risks must be equivalent to those of standard open-chest operations. This study analyzed the outcomes of patients recorded in the multicenter Port Access (PA) International Registry to establish operative risks.Data were analyzed for intent to treat in 583 patients who underwent PA coronary artery bypass grafting (CABG), 184 who underwent PA mitral valve replacement, and 137 who underwent PA mitral valve repair at 121 centers.Port Access was attempted in 1,063 patients and completed in 1,004 (94%). The operative mortality rate was 1% for PA CABG, 3.3% for PA mitral valve replacement, and 1.5% for PA mitral valve repair. Perioperative morbidity was low in all categories: stroke = 1.1% to 3.6%, myocardial infarction = 0 to 1%, primary procedure reoperation = 0 to 0.7%, renal failure = 0.2% to 0.7%, multiorgan failure = 0 to 0.5%, and atrial fibrillation = 5% to 7.3%.Data on 1,063 patients from 121 centers demonstrate that PA CABG and PA mitral valve operations can be performed safely, with morbidity and mortality rates similar to those associated with open-chest operations. Further studies are indicated to establish the long-term efficacy of this method and to analyze its effect on recovery time.
View details for Web of Science ID 000078970500008
View details for PubMedID 10086524
View details for PubMedID 9682259
Because of advances in video-assisted general and thoracic surgery, minimally invasive cardiac surgery has been successfully performed experimentally and clinically. Recently described techniques of less invasive mitral valve surgery include limited right thoracotomy, parasternal incision, and partial sternotomy. These methods have been coupled to video-assisted thoracoscopy to further decrease the incision size. Cardiopulmonary bypass (central or peripheral) and either hypothermic fibrillatory arrest or cardioplegic arrest are used. The Port-Access approach is a catheter-based system that provides effective cardiopulmonary bypass, cardioplegic arrest, and ventricular decompression. At Stanford University, 10 Port-Access mitral valve procedures were performed between May 1996 and January 1997. The mean age of the patients (eight men and two women) was 54 +/- 7 (SD) years. Nine patients had severe mitral regurgitation from myxomatous degeneration, and one suffered from severe mitral regurgitation and moderate mitral stenosis from a rheumatic etiology. Five patients underwent mitral valve replacement, and five underwent mitral valve repair. There was no operative mortality. The mean incision length was 8.1 +/- 2.5 cm. The aortic "cross-clamp" time was 99 +/- 22 minutes, and the cardiopulmonary bypass time was 151 +/- 52 minutes. The total hospitalization averaged 4.3 +/- 1.4 days. One patient developed third-degree atrioventricular block, requiring a prolonged stay in the intensive care unit and pacemaker placement; the same patient was found to have a perivalvular leak on follow-up, requiring reoperation at 3 months. Port-Access mitral valve procedures can be performed safely with satisfactory outcome. Greater clinical experience and long-term follow-up are necessary to fully assess these less invasive techniques of mitral valve surgery.
View details for PubMedID 9352947
Minimally invasive cardiac surgery has generated a tremendous amount of enthusiasm in the cardiology and cardiac surgical communities. Coronary revascularization without cardiopulmonary bypass through a small anterior thoracotomy or mediastinotomy has been introduced as an alternative to the conventional approach. An endovascular or port-access technique for cardiopulmonary bypass and cardioplegic arrest has been developed for use in cardiac surgery. This peripherally based system achieves aortic occlusion, cardioplegia delivery, and left ventricular decompression; thus, coronary revascularization and various cardiac procedures can be effectively performed in a less invasive fashion than conventional median sternotomy. Continued technical advances in minimally invasive cardiac surgery will facilitate these procedures, increase patient safety, and contribute to acceptable long-term results.
View details for Web of Science ID A1997YA09600008
View details for PubMedID 9352176
A method for monitoring patients was evaluated in a clinical trial of minimally invasive port-access cardiac surgery with closed chest endovascular cardiopulmonary bypass.Cardiopulmonary bypass was conducted in 25 patients through femoral cannulas. An endovascular pulmonary artery vent was placed in the main pulmonary artery through a jugular vein. For mitral valve surgery, a catheter was placed in the coronary sinus for delivery of cardioplegia. A balloon catheter ("endoaortic clamp," EAC) used for occlusion of the ascending aorta, delivery of cardioplegia, aortic root venting, and pressure measurement was inserted through a femoral artery and initially positioned by use of fluoroscopy and transesophageal echocardiography (TEE). Potential migration of the EAC was monitored by (1) TEE of the ascending aorta, (2) pulsed-wave Doppler of the right carotid artery, (3) balloon pressure, (4) comparison of aortic root pressure and right radial artery pressure, and (5) fluoroscopy. TEE, fluoroscopy, and pressure measurement were effective in monitoring catheter insertion and position. With inadequate balloon inflation, migration of the EAC toward the aortic valve could be detected with TEE. During administration of cardioplegia, TEE showed movement of the balloon away from the aortic valve, and migration into the aortic arch was detectable with loss of carotid Doppler flow. Stability of EAC position was demonstrated with appropriate balloon volume. Cardioplegic solution was visualized in the aortic root, and aortic root pressure changed appropriately during administration of cardioplegia. Venous cannula position was optimized with TEE and endopulmonary vent flow measurement.An effective method has been developed for monitoring patients and the catheter system during port-access cardiac surgery.
View details for Web of Science ID A1997XM00300034
View details for PubMedID 9244226
A less invasive approach to cardiac surgery has been propelled by recent advances in video-assisted surgery. Previous obstacles to minimally invasive cardiac operations with cardioplegic arrest included limitations in operative exposure, inadequate perfusion technology, and inability to provide myocardial protection.Port-access technology allows endovascular aortic occlusion, cardioplegia delivery, and left ventricular decompression. The endoaortic clamp is a triple-lumen catheter with an inflatable balloon at its distal end. Antegrade cardioplegia is delivered through a central lumen, which also acts as an aortic root vent, a second lumen is used as an aortic root pressure monitor, and a third lumen is used for balloon inflation to provide aortic occlusion.Experimental and clinical studies have demonstrated the feasibility of port-access coronary artery bypass grafting and port-access mitral valve procedures. Endovascular cardiopulmonary bypass using the endoaortic clamp was effective in achieving cardiac arrest and myocardial protection to allow internal mammary artery to coronary artery anastomosis in a still and bloodless field. Intracardiac procedures, such as mitral valve replacement or repair, have been successfully performed clinically.The port-access system effectively achieves cardiopulmonary bypass and cardioplegic arrest, thereby enabling the surgeon to perform cardiac procedures in a minimally invasive fashion. This system provides for endovascular aortic occlusion, cardioplegia delivery, and left ventricular decompression.
View details for Web of Science ID A1997XH60000008
View details for PubMedID 9203594
We developed a method of closed-chest cardiopulmonary bypass to arrest and protect the heart with cardioplegic solution. This method was used in 54 dogs and the results were retrospectively analyzed.Bypass cannulas were placed in the right femoral vessels. A balloon occlusion catheter was passed via the left femoral artery and positioned in the ascending aorta. A pulmonary artery vent was placed via the jugular vein. In 17 of the dogs retrograde cardioplegia was provided with a percutaneous coronary sinus catheter.Cardiopulmonary bypass time was 111 +/- 27 minutes (mean +/- standard deviation) and cardiac arrest time was 66 +/- 21 minutes. Preoperative cardiac outputs were 2.9 +/- 0.70 L/min and postoperative outputs were 2.9 +/- 0.65 L/min (p = not significant). Twenty-one-French and 23F femoral arterial cannulas that allowed coaxial placement of the ascending aortic balloon catheter were tested in 3 male calves. Line pressures were higher, but not clinically limiting, with the balloon catheter placed coaxially.Adequate cardiopulmonary bypass and cardioplegia can be achieved in the dog without opening the chest, facilitating less invasive cardiac operations. A human clinical trial is in progress.
View details for Web of Science ID A1997XH23000044
View details for PubMedID 9205178
To extend the applications of minimal access cardiac surgery, an endovascular cardiopulmonary bypass (CPB) system that allows cardioplegia delivery and cardiac venting was used to perform bilateral internal mammary artery (IMA) bypass grafting in six dogs.The left IMA (LIMA) was taken down thoracoscopically from three left lateral chest ports, followed by the right IMA (RIMA) from the right side. One left-sided port was extended medially 5 cm with or without rib resection, to expose the pericardium. Both IMAs were divided and exteriorized through the left anterior mediastinotomy. Flow and pedicle length were satisfactory in all cases. Femoral-femoral bypass was used and the heart arrested with antegrade delivery of cardioplegic solution via the central lumen of a balloon catheter inflated to occlude the ascending aorta. All anastomoses were made through the mediastinotomy under direct vision. In five studies the RIMA was attached to the left anterior descending artery (LAD) and the LIMA to the circumflex, and in one study the RIMA was tunneled through the transverse sinus to the circumflex and the LIMA was anastomosed to the LAD. All animals were weaned from CPB in sinus rhythm without inotropes. CPB duration was 108 +/- 27 minutes (mean +/- SD) and the clamp duration was 54 +/- 10 minutes.Preoperative and postoperative cardiac outputs were 2.9 +/- 0.71/min and 2.4 +/- 0.31/min, respectively (p = NS), and corresponding pulmonary artery occlusion pressures were 6 +/- 3 mmHg and 7 +/- 2 mmHg, respectively (p = NS). All 12 grafts were demonstrated to be fully patent. Postmortem examination revealed well aligned pedicles and correctly grafted target vessels.This canine model demonstrates the potential for a less invasive approach to the surgical management of left main coronary artery disease in humans.
View details for Web of Science ID A1997XU60700002
View details for PubMedID 9169362
In the past decade, laparoscopic and thoracoscopiC technology have significantly and irreversibly altered the approach to many general and thoracic surgical diseases. With advances in laparoscopy and thoracoscopy, the concept of a minimally invasive approach to cardiac surgery has been realized.
View details for PubMedID 16160987
The objective was to assess mitral valve replacement in a minimally invasive fashion by means of port-access technology.Fifteen dogs, 28 +/- 3 kg (mean +/- standard deviation), were studied with the port-access mitral valve replacement system (Heartport, Inc., Redwood City, Calif.). Eleven dogs underwent acute studies and were sacrificed immediately after the procedure. Four dogs were allowed to recover and then were sacrificed 4 weeks after operation. Cardiopulmonary bypass was conducted by femoral cannulation with an endovascular balloon catheter for aortic occlusion, root venting, and antegrade delivery of cardioplegic solution. Catheters were inserted in the jugular vein for pulmonary artery venting and retrograde delivery of cardioplegic solution. Through the oval port, a prosthesis (St. Jude Medical, Inc., St. Paul, Minn., or CarboMedics, Inc., Austin, Texas) was inserted through the left atrial appendage and secured to the anulus with sutures. Deairing was performed.Cardiopulmonary bypass duration was 114 +/- 24 minutes and aortic crossclamp time was 68 +/- 14 minutes. All animals were weaned from cardiopulmonary bypass in sinus rhythm. Cardiac output and pulmonary artery occlusion pressure were unchanged (2.8 +/- 0.7 L/min and 7 +/- 3 mm Hg before operation vs 2.6 +/- 0.6 L/min and 9 +/- 4 mm Hg after operation). There was no mitral regurgitation according to left ventriculography in 13 of 15 dogs. In two dogs there was interference with prosthetic valve closure by residual native anterior leaflet tissue. Pathologic examination otherwise showed normal healing without perivalvular discontinuity. Microscopic studies showed no damage to the valve surfaces. Transthoracic echocardiography of the four dogs in the long-term study showed normal ventricular and prosthetic valve function 4 weeks after the operation.Mitral valve replacement with a minimally invasive method has been demonstrated in dogs. A clinical trial is in progress.
View details for Web of Science ID A1996VV63200028
View details for PubMedID 8911323
Our goal is to perform minimally invasive coronary artery bypass grafting without sacrificing the benefits of myocardial protection with cardioplegia.Twenty-three dogs underwent acute studies and 4 dogs underwent survival studies. The left internal mammary artery was taken down using a thoracoscope. Cardiopulmonary bypass was conducted via femoral cannulas and using an endovascular balloon catheter for ascending aortic occlusion, root venting, and delivery of antegrade blood cardioplegia. Pulmonary artery venting was achieved with a jugular vein catheter. An internal mammary artery-to-coronary artery anastomosis was performed using a microscope through a 10 mm port.All animals were weaned from cardiopulmonary bypass in sinus rhythm without inotropes. Cardiopulmonary bypass duration was 104 +/- 28 minutes and aortic clamp duration was 61 +/- 22 minutes. Cardiac output and pulmonary artery occlusion pressure were unchanged. The internal mammary artery was anastomosed to the left anterior descending artery (25) or the first diagonal (2) with patency shown in 25 of 27. One dog in the survival study had a very short internal mammary artery pedicle under tension and was euthanized for excessive postoperative hemorrhage. Three weeks postoperatively the remaining dogs had angiographically patent anastomoses, normal transthoracic echocardiograms, and histologically normal healing and patent grafts.Endovascular cardiopulmonary bypass using a balloon catheter is effective in arresting and protecting the heart to allow thoracoscopic internal mammary artery-to-coronary artery anastomosis.
View details for PubMedID 8694602
View details for Web of Science ID A1996UD16400079
Minimally invasive surgical methods have been developed to provide patients the benefits of open operations with decreased pain and suffering. We have developed a system that allows the performance of cardiopulmonary bypass and myocardial protection with cardioplegic arrest without sternotomy or thoracotomy. In a canine model, we successfully used this system to anastomose the internal thoracic artery to the left anterior descending coronary artery in nine of 10 animals. The left internal thoracic artery was dissected from the chest wall, and the pericardium was opened with the use of thoracoscopic techniques and single lung ventilation. The heart was arrested with a cold blood cardioplegic solution delivered through the central lumen of a balloon occlusion catheter (Endoaortic Clamp; Heartport, Inc., Redwood City, Calif.) in the ascending aorta, and cardiopulmonary bypass was maintained with femorofemoral bypass. An operating microscope modified to allow introduction of the 3.5x magnification objective into the chest was positioned through a 10 mm port over the site of the anastomosis. The anastomosis was performed with modified surgical instruments introduced through additional 5 mm ports. In the cadaver model (n = 7) the internal thoracic artery was harvested and the pericardium opened by means of similar techniques. A precise arteriotomy was made with microvascular thoracoscopic instruments under the modified microscope on four cadavers. In three other cadavers we assessed the exposure provided by a small anterior incision (4 to 6 cm) over the fourth intercostal space. This anterior port can assist in dissection of the distal internal thoracic artery and provides direct access to the left anterior descending, circumflex, and posterior descending arteries. We have demonstrated the potential feasibility of grafting the internal thoracic artery to coronary arteries with the heart arrested and protected, without a major thoracotomy or sternotomy.
View details for PubMedID 8601971
View details for Web of Science ID A1994PN41701385
Isolated aortic (n = 857) or mitral (n = 793) valve replacement with a porcine bioprosthesis was performed in 1650 patients between 1971 and 1980. Follow-up (total = 12,012 patient-years) extended to more than 15 years and was 96% complete. Patient age ranged from 16 to 87 years; mean age was 59 +/- 11 years (+/- 1 standard deviation) for the aortic valve replacement cohort and 56 +/- 12 years for the mitral valve replacement cohort. The operative mortality rates were 5% +/- 1% (+/- 70% confidence limits) and 8% +/- 1%, respectively, for the aortic and mitral subgroups. Estimated freedom from structural valve deterioration (+/- 1 standard error of the mean) after 10 and 15 years was significantly higher for the aortic than for the mitral valve replacement subgroup (85% +/- 0.4% and 63% +/- 3% versus 78% +/- 2% and 45% +/- 3%, respectively, p = 0.001). Reoperation-free actuarial estimates were also significantly greater for the aortic valve replacement cohort: 83% +/- 2% and 57% +/- 3% versus 78% +/- 2% and 43% +/- 3% for mitral valve replacement at 10 and 15 years, respectively. The mortality rate for reoperative aortic valve replacement was 11% +/- 1%; it was 8% +/- 1% for reoperative mitral valve replacement. Importantly, the estimates of freedom from valve-related death (including sudden, unexplained deaths) were relatively high at 10 and 15 years: 78% +/- 2% and 69% +/- 3% in the aortic cohort and 74% +/- 2% and 63% +/- 3% in the mitral cohort (p = not significant). Excluding sudden, unexplained deaths, these estimates were 81% +/- 3% (aortic) and 73% +/- 4% (mitral) at 15 years. Thromboembolism-free rates were 84% +/- 3% (aortic) and 78% +/- 6% (mitral) at 15 years, and freedom from anticoagulant-related hemorrhage was 96% +/- 1% and 89% +/- 2%, respectively. At the time of current follow-up, 13% of patients having aortic valve replacement and 50% of patients having mitral valve replacement were receiving warfarin sodium. The hazard functions for thromboembolism and prosthetic valve endocarditis were constant and remained less than 1%/pt-yr over the entire follow-up period.(ABSTRACT TRUNCATED AT 400 WORDS)
View details for PubMedID 1735989