Thomas Burdon

View details for DOI 10.1016/j.jtcvs.2008.07.006

View details for Web of Science ID 000274014300050

View details for PubMedID 19660256

Abstract

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

Abstract

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

Abstract

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

Abstract

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

Abstract

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

Abstract

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

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

Abstract

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

Abstract

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

Abstract

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

Abstract

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

Abstract

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

Abstract

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

Abstract

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

View details for DOI 10.1177/026765919801300408

View details for Web of Science ID 000208340400007

Abstract

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

Abstract

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

Abstract

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

Abstract

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

Abstract

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

Abstract

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 Web of Science ID A1996UB98000013

View details for PubMedID 8601971

Abstract

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 Web of Science ID A1992HD22500008

View details for PubMedID 1735989