Port-Access Coronary Artery Bypass Grafting Research Articles

Multivessel Coronary Bypass Grafting With Minimal Access Using Cardiopulmonary Bypass (Port Access Approach)

p ort access coronary artery bypass grafting (PACABG) has evolved significantly since its introduction in 1996. New technological developments, procedural changes, and operator experience have led to improved understanding of the potential benefits anti pitfalls of the procedure. At our hospitals, Memorial Mission Hospital and New York University Hospital, more than 600 coronary revascularizations have been performed with the port access platform. Tiffs article reviews the teclmique, patient selection process, and results associated with the procedure. PRINCIPLES The technique of PACABG is based on the principles that have made standard on-pump CABG a successfnl operation for treating coronary artery disease. Cardioplegic-induced cardiac arrest with cardiopulmonary support allows for improved visibility, enhanced precision of anastomosis, and cardiac decompression with access to all regions of the heart for complete target revascularization. With port access, the cardiac operation is performed via a small anterior thoracotomy while the patient is maintained on a new system of cardiopulmonary bypass that uses peripheral cannulation to support the patient during peripherally manipulated cardiac arrest. Thus, the patient's recovery is not impaired by skeletal healing. The hypothesis is that the sternotomy itself slows the recovery process and adds morbidity to the operation that may be avoided with peripheral perfusion. This cannula system was refined through extensive laboratory studies confirnfing its efficacy and safety. Reliable myocardial protection and cardiopulmonary support have been documented with this technique, l When clinical trials were begun in 1996, it became evident that significant changes in the operating room were required to achieve excellent outcomes. First, the anesthesia, perfusion, nursing, and surgical staffs were required to learn new skill sets. Second, communication within and between these disciplines, along with critical analysis of each member's role, required review and expansion. This team approach has been shown to be one of the crucial retluirements to suecessfifl adoption of this new procedure. The importance of nonsurgeon ioput to the proeeditre cannot be overemphasized. Suecessfid apl)lieation of PACABG is not solely al)out a surgeon mastering a new operation, but rather about an operating team bringing together a critical mass of skills to perform this new procedure. 2 The initial CABG experience was focused on the area from the left internal mammary artery (LIMA) to left anterior descending artery (LAD) bypass. 3 Subsequently, with operator experience, muhivessel procedures became more common. With these initial nmhivessel procedures, graft inflow was based on the LIMA. The LIMA was anastomosed to the LAD, and radial arteries or saphenous veins were taken as side grafts to non-LAD targets. As surgeons continued to modify the operation, access to the aorta became routinely achievable. This enabled the more conventional operation of non-IMA conduits to be based off the aorta, This significantly decreased operative times and simplified and improved the applicability of the procedure. 4

Port-access coronary artery bypass grafting: technique and comparative results

Background. Interest in minimally invasive coronary artery bypass grafting (CABG) continues to grow, and the techniques evolve. Our study examines the technical strategies of port-access (PA) CABG and compares results between PA CABG and conventional CABG. Methods. Two hundred and twenty-nine consecutive patients underwent PA CABG from December 1996 through July 1998. Postoperative complications were compared with a matched cohort of conventional access patients. Operative technique and times were reviewed in the PA group. Results. The average Society of Thoracic Surgeons (STS) risk assessment was 1.3 in both groups. Observed mortality was 0.9%. Complications of stroke, perioperative myocardial infarction, and atrial fibrillation were not significantly different between the two groups. Reoperation for bleeding was more likely in the PA group, while infections were more likely in the sternotomy group ( p < 0.05). Transfusion requirements and postoperative length of stay were lower in the PA group ( p < 0.05). Conclusions. Early results were similar between these two low-risk cohort groups. These findings support continued careful use of port-access revascularization in low-risk patients. Close follow-up of outcomes is essential to define the appropriateness of port-access techniques in patients requiring surgical revascularization.

Results of a prospective multicenter study on port-access coronary bypass grafting

Background. We reviewed the initial patient series of three institutions performing large volume port-access (PA) coronary artery bypass grafting (CABG) to evaluate the efficacy of this new procedure. Methods. From October 1996 until June 1998, 302 consecutive patients underwent isolated CABG using the PA approach. Patients (mean age 60.7 years) were predominantly male (77.5%) and received a mean of 2.3 distal anastomoses; few were New York Heart Association class III or IV (15.9%). The distribution of the number of grafts was: 76 (25.2%) single, 110 (36.4%) double, 73 (24.2%) triple, and 43 (14.2%) four or more bypass grafts. The Society of Thoracic Surgeons (STS) Database data collection form was used prospectively by all three institutions to define patient risk factors and record outcomes. Results. Total 30-day hospital mortality was 0.99% compared to the STS-database-model-predicted risk of 1.2%. Complication rates for the PA CABG patients compared with risk-matched morbidity rates from the STS data for CABG alone were: reoperation for bleeding, 3.3% versus 1.9%; ventilatory support more than 1 day, 1.7% versus 3.8%; stroke, 1.7% versus 1.2%; and perioperative transmural myocardial infarction 0% versus 1.3%. Conclusions. The STS CABG risk-adjusted model demonstrates that the 30-day mortality for patients undergoing PA CABG is lower than predicted for traditional CABG patients (confidence intervals not available). Likewise, the morbidity was low, with minimal ventilatory support, pulmonary complications, and atrial fibrillation. The port-access technique is an acceptable strategy for multivessel bypass grafting.

Some Thoughts on Minimally Invasive Coronary Bypass

With the advent of minimally invasive and off-pump coronary artery bypass grafting (CABG), cardiac surgery has reached a “strategic inflexion point” at which alternate pathways offer both dangers and opportunities that may lead to increased success or dismal failure. Since the price of a cardiac surgeon’s misjudgment is ultimately paid by the patient, at critical junctures it is vital to maintain our profession’s tradition of vigorous discussion and debate about new technologies. Most of my comments will be about off-pump coronary artery bypass (OPCAB) because avoidance of the pump seems a worthwhile goal. In contrast, with current technology, the complexity and risk of port-access coronary bypass with the pump seem to outweigh the benefit of merely avoiding a sternotomy. This view may change as we improve port-access techniques but I know from personal experience that sternotomy incisions are not so bad. Furthermore, portaccess CABG is done in relatively few centers compared with off-pump CABG.

First report of the port access international registry

Background. 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. Methods. 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. Results. 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%. Conclusions. 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.

Port-Access coronary artery bypass grafting: technical considerations and results.

This study reviews the results of an initial experience with minimally invasive coronary bypass surgery using the Port-Access approach in terms of early outcome and safety. Between October 1996 and July 1997 49 Port-Access minimally invasive coronary artery bypass grafting procedures were performed at our institution. The patients' mean age was 59.8 years (range 34 to 82 years). Sixteen patients received single vessel and 37 patients received multivessel bypass grafts. There were no operative deaths and no perioperative myocardial infarctions, neurological deficits, or conversions to sternotomy. Early complications included reoperation due to bleeding in 4 patients, reoperation for a pulmonary embolus in 1 patient, and angioplasty for occlusion of a right coronary artery graft in 2 patients. Postoperative angiograms were obtained in 86% (42/49) of the patients and showed 100% patency for left internal mammary artery to left anterior descending artery grafts and 96% patency for all grafts. These results demonstrate that Port-Access coronary artery bypass grafting using endovascular techniques for cardiopulmonary bypass and cardioplegic arrest can be performed safely with minimal morbidity and mortality. This technique allows multivessel revascularization on a protected, arrested heart with excellent anastomotic precision and reproducible early graft patency. Expanded use of Port-Access techniques is indicated in patients with multivessel coronary artery disease and the technique should be considered for patients with left anterior descending artery restenosis and patients with complex left anterior descending artery lesions where angioplasty results are suboptimal.

Port-Access cardiac surgery using endovascular cardiopulmonary bypass: theory, practice, and results.

Reduction of surgical trauma is the aim of minimally invasive cardiac surgery. This can be achieved by reducing the size of the incision or by eliminating or changing the cardiopulmonary bypass system. However, certain cardiac surgical procedures, such as valvular surgery and complex multivessel coronary artery surgery, are not feasible without the use of cardiopulmonary bypass. Therefore endovascular cardiopulmonary bypass may allow reduction of surgical trauma for these patients. Since its first application in April 1995, more than 1100 procedures have been performed worldwide using the EndoCPB endovascular cardiopulmonary bypass system. The authors' experience consists of 60 Port-Access coronary artery bypass grafting procedures, 34 Port-Access mitral valve procedures (18 replacements, 16 repairs), 5 atrial septal defect closures, and 3 atrial myxoma removals. The patient survival rate was 99%, the incidence of perioperative stroke was 1%, and the incidence of aortic dissection was 1%. In the Port-Access mitral valve and atrial septal defect patients, the survival rate was 100% with no peri- or postoperative complications. Peri- and postoperative transesophageal echocardiography revealed no perivalvular leak or remaining mitral insufficiency after valve repair. The EndoCPB endovascular cardiopulmonary bypass system allows the application of true Port-Access minimally invasive cardiac surgery in procedures that require the use of cardiopulmonary bypass and cardioplegic arrest. Sternotomy and its potential complications can be avoided, and the surgical procedures can be performed safely on an empty, arrested heart with adequate myocardial protection.

Minimally invasive port-access coronary artery bypass grafting with early angiographic follow-up: Initial clinical experience

Objective: New techniques for minimally invasive coronary artery bypass grafting have recently emerged. The purpose of this study was to determine the safety and efficacy of Port-Access (Heartport, Inc., Redwood City, Calif.) coronary revascularization and to evaluate with angiography the early graft patency rate with this new approach. Methods: From October 1996 to May 1997, 31 patients underwent Port-Access coronary artery bypass grafting with an anterior minithoracotomy and endovascular-occlusion cardiopulmonary bypass. There were 26 men and 5 women with a mean age of 62 years (range 42 to 82 years). Fifteen patients underwent single bypass; 12 patients underwent double bypass, and 4 patients underwent triple bypass. Bypass conduits included the left internal thoracic artery ( n = 30), right internal thoracic artery ( n = 2), radial artery ( n = 10), and saphenous vein ( n = 6). Three sequential grafts were used. Angiographic studies of the bypass grafts were performed in 27 of 31 patients (87%). Results: There were no deaths, neurologic deficits, myocardial infarctions, or aortic dissections. Conversion to sternotomy was not required in any case. There were two reoperations for bleeding, one reoperation for tamponade, and one reoperation for pulmonary embolus. Postoperative angiography revealed anastomotic patency of the left internal thoracic artery to left anterior descending artery in 26 of 26 grafts (100%) with overall anastomotic patency in 43 of 44 grafts (97.7%). Conclusion: These results demonstrate that Port-Access coronary artery bypass can be performed accurately and safely with acceptable morbidity. This approach allows for multivessel revascularization on an arrested, protected heart with excellent anastomotic precision and reproducible early graft patency. (J Thorac Cardiovasc Surg 1998;115:1101-10)

Port-Access Coronary Artery Bypass Grafting With the Use of Cardiopulmonary Bypass and Cardioplegic Arrest

Background. To reduce surgical trauma, we performed minimally invasive Port-Access (Heartport Inc, Redwood City, CA) coronary artery bypass grafting with cardiopulmonary bypass and cardioplegic arrest. Methods. Thirty-six men and 6 women with a median age of 59 years (range, 31 to 75 years) and isolated lesions of the left anterior descending branch of the coronary artery underwent Port-Access coronary artery bypass grafting. A small (6- to 9-cm) incision was made parasternally on top of the fourth rib. The left internal thoracic (mammary) artery was dissected and taken down through the minithoracotomy either alone or using an additional thoracoscopic approach. Cardiopulmonary bypass was instituted through femoral cannulation, and an additional endoarterial balloon catheter (Heartport Inc) was introduced into the ascending aorta for aortic occlusion, aortic root venting, and the delivery of cold antegrade crystalloid cardioplegia. After cardioplegic arrest, the left internal mammary artery was anastomosed to the left anterior descending artery under direct vision. Results. The median left internal mammary artery takedown time was 49.5 ± 21.9 minutes, the duration of cardiopulmonary bypass was 59.5 ± 32.8 minutes, the aortic occlusion time was 28.5 ± 7.9 minutes, the intensive care unit stay was 1.0 ± 3.2 days, and the total hospital stay was 5.0 ± 2.5 days. Intraoperative angiograms were done in the first 10 patients and showed patent left internal mammary artery grafts without anastomotic complications in all cases. Two arterial dissections, including one aortic dissection, were observed in patients with preexisting peripheral vascular disease. The other complications were minor. All but 1 patient recovered well, with no major limitations in their daily activities. Conclusions. Using this minimally invasive method, sternotomy-related complications can be avoided, the hospital stay can be reduced, and a safe coronary artery bypass grafting procedure can be performed with the advantage of cardiopulmonary bypass and cardioplegic arrest as are used routinely in conventional coronary artery operations.

Single and multivessel port-access coronary artery bypass grafting with cardioplegic arrest: Technique and reproducibility

Objectives: Although minimally invasive coronary artery bypass grafting is now feasible, using this technique to perform anastomoses on the beating or fibrillating heart may yield poorer graft patency than the standard open techniques that use cardioplegic arrest. This study tested the feasibility and anastomotic reproducibility of minimally invasive coronary bypass using newly developed port-access coronary artery bypass technology (Heartport, Inc., Redwood City, Calif.), which allows endovascular cardiopulmonary bypass, cardiac venting, aortic occlusion, and cardioplegic arrest for internal thoracic artery–coronary artery anastomoses. Methods: Nineteen dogs had thoracoscopic takedown of either single ( n = 14) or bilateral ( n = 5) internal thoracic arteries followed by minimally invasive coronary bypass with cardioplegic arrest, done by means of the port-access system. The anastomotic technique was modified after the fourth animal by switching from a microscope to a 2.5 cm oval port and performing a conventional anastomosis with operative loupes. The adequacy of delivery of cardioplegic solution, ventricular decompression, and anastomotic patency was assessed. Results: The crossclamp and bypass times were 50 ± 15 minutes and 87 ± 28 minutes (mean ± standard deviation), respectively. The mean myocardial temperature after cardioplegia was 17° ± 1° C and the aortic pressure (–3 ± 9 mm Hg) and pulmonary artery pressure (4 ± 1 mm Hg) were low throughout the procedure. All animals were weaned from bypass without inotropic agents. Angiograms and autopsies demonstrated successful thoracic artery takedown and anastomotic patency in 18 of 19 animals, with 100% anastomotic patency after the technique had been modified after the fourth animal. Conclusion: This study describes a reproducible technique for minimally invasive coronary bypass that allows myocardial protection, anastomotic precision, and predictable thoracic artery graft patency. Clinical trials are indicated(J Thorac Cardiovasc Surg 1997;114:46-52)

Port-access cardiac operations with cardioplegic arrest

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.

Port-access coronary artery bypass grafting: A proposed surgical method

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 3.5× 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. (J T HORAC C ARDIOVASC S URG 1996;111:567-73)