Off-pump coronary artery bypass surgery: To do or not to do? Current best available evidence

Abstract

CORONARY REVASCULARIZATION plays an important role in the management of patients with ischemic heart disease. Its principle builds on restoring antegrade flow, thereby relieving angina. Cardiopulmonary bypass (CPB) has been used for coronary artery bypass grafting (CABG) for over 3 decades.1Mack M.J. Advances in the treatment of coronary artery disease.Ann Thorac Surg. 2003; 76: S2240-S2245Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar Surgeons have required still and bloodless fields in which to perform a microvascular conduit to coronary anastomosis. The invention of CPB enabled cardiac surgeons to perform intracardiac and extracardiac procedures with increasing ease, thereby advancing the surgical care of both congenital and acquired heart disease.1Mack M.J. Advances in the treatment of coronary artery disease.Ann Thorac Surg. 2003; 76: S2240-S2245Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar However, CPB has many known pathologic effects, which include volume retention, coagulopathy, release of systemic inflammatory mediators, pulmonary dysfunction, stroke, and neurocognitive changes.2Wan S. Yim A.P. Ng C.S. et al.Systematic organ protection in coronary artery surgery with or without cardiopulmonary bypass.J Card Surg. 2002; 17: 529-535Crossref PubMed Scopus (12) Google Scholar The recent upsurge in interest in off-pump coronary artery bypass (OPCAB) surgery attempts to avoid these deleterious effects. OPCAB, also known as “beating-heart” surgery, has the advantages of simplicity, avoidance of inflammatory response caused by CPB, and a decreased need for blood transfusion.3Gerola L.R. Buffolo E. Jasbik W. et al.Off-pump versus on-pump myocardial revascularization in low-risk patients with one- or two- vessel disease Perioperative results in a multicenter randomized controlledtrial.Ann Thorac Surg. 2004; 77: 569-573Abstract Full Text Full Text PDF PubMed Scopus (89) Google Scholar Nevertheless, OPCAB may be technically difficult in some patients and it involves a steep learning curve. Potential pitfalls include incomplete revascularization, ischemia during temporary target-artery occlusion, and suboptimal anastomoses.4Bergsland J. D’Ancona G. Karamanoukian H. et al.Technical tips and pitfalls in OPCAB surgery The Buffalo experience.Heart Surg Forum. 2000; 3: 189-193PubMed Google Scholar Because of the need for special equipment, OPCAB can be expensive and time consuming. This review discusses the historic background, indications, innovations in the technique, and technology of OPCAB and compares the efficacy and safety of this technique with conventional coronary artery bypass graft surgery in the light of current best available evidence. Contrary to the suggestion of Ascione and coauthors5Ascione R. Lloyd C.T. Underwood M.J. et al.On-pump versus off-pump coronary revascularization Evaluation of renal function.Ann Thorac Surg. 1999; 68: 493-498Abstract Full Text Full Text PDF PubMed Scopus (311) Google Scholar that “operation on a beating heart is a relatively new surgical procedure,” OPCAB surgery is not a new technique. In the 1950s, before CPB came into widespread use, Murray and Longmire performed a coronary endarterectomy with saphenous vein or internal mammary artery grafts.6Westaby S. Bennetti F.J. Less invasive coronary surgery consensus from the Oxford Meeting.Ann Thorac Surg. 1996; 62: 924-931Abstract Full Text Full Text PDF PubMed Scopus (86) Google Scholar Myocardial revascularization by anastomosing the internal mammary artery to the coronary artery was advocated by Demikhov,7Demikhov V.P. Experimental transplantation of vital organs (authorized translation from Russian by Basil Haigh).in: Consultant’s Beureau Enterprises, New York, NY1962: 220-227Google Scholar who undertook a canine study of this technique in 1952; 4 of his dogs survived for more than 2 years with patent grafts. In a similar time frame, Murray independently achieved similar results.6Westaby S. Bennetti F.J. Less invasive coronary surgery consensus from the Oxford Meeting.Ann Thorac Surg. 1996; 62: 924-931Abstract Full Text Full Text PDF PubMed Scopus (86) Google Scholar In 1962, Sabiston used a saphenous vein graft to bypass the right coronary artery, and in 1964, Garrett bypassed the left anterior descending artery (LAD).8Westaby S. Landmarks in Cardiac Surgery.in: Isis Medical Media LTD, Oxford1997: 196Google Scholar That same year, Kolesov9Spencer F.C. Galloway A.C. Colvin S.B. Surgical management of coronary artery disease.in: Sabiston Jr, D.C. Spencer F.C. Surgery of the Chest. ed 6. Saunders, Philadelphia, PA1995: 1884-1885Google Scholar anastomosed left internal mammary artery (LIMA) to a marginal branch of the circumflex artery. All of these procedures were done off-pump on a beating heart. After 1968, CABG with CPB was widely adopted, but OPCAB continued to be performed by some surgeons.10Favoloro R.G. Effler D.B. Groves L.K. et al.Direct myocardial revascularization by saphenous vein graft. Present operative technique and indications.Ann Thorac Surg. 1970; 10: 97-111Abstract Full Text PDF PubMed Google Scholar, 11Ankeney J.L. To use or not to use the pump oxygenator in coronary bypass operations.Ann Thorac Surg. 1975; 19: 108-109Abstract Full Text PDF PubMed Google Scholar Hence, OPCAB was originally the only possible approach and, after the advent of modern CPB techniques, was largely viewed as outmoded.12Cooley D.A. Con: Beating-heart surgery for coronary revascularization: Is it the most important development since the introduction of the heart-lung machine?.Ann Thorac Surg. 2000; 70: 1779-1781Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar However, with the introduction of minimally invasive coronary surgery and mechanical methods of target-artery stabilization, interest in OPCAB has been renewed. In early to mid 1997, several North American surgeons became interested in using the Medtronic Octopus System (Medtronic, Inc, Minneapolis, MN). In 1998, Jansen and coworkers13Jansen E.W.L. Borst C. Lahpor J.R. et al.Coronary artery bypass grafting without cardiopulmonary bypass using the Octopus method Results in the first one hundred patients.J Cardiovasc Thorac Surg. 1998; 116: 60-67Abstract Full Text Full Text PDF PubMed Scopus (160) Google Scholar reported the design, experimental evaluation, and the first clinical use of this novel suction-based mechanical coronary artery stabilizing system. After federal approval of the device, they began clinical application of this stabilizer.14Spooner T. Hart J.C. Pym J. A two-year, three-institution experience with the Medtronic Octopus Systematic off-pump surgery.Ann Thorac Surg. 1999; 68: 1478-1481Abstract Full Text Full Text PDF PubMed Scopus (40) Google Scholar Early experience with the device was limited to vessels on the anterior surface of the heart, which were easily bypassed with excellent stabilization. Lateral and posterior vessels presented technical challenges because hemodynamic tolerance to the cardiac displacement necessary for exposure was poor. After experimental evaluation of the hemodynamic consequences of vertical cardiac displacement, techniques were developed and shared and gradually more surfaces of the heart could be approached safely.15Grundeman P.F. Borst C. Verlaan C.W.J. et al.Exposure of circumflex branches in the tilted, beating porcine heart Echocardiographic evidence of right ventricular deformation and the effect of right- or left-heart bypass.J Thorac Cardiovasc Surg. 1999; 118: 316-323Abstract Full Text Full Text PDF PubMed Scopus (112) Google Scholar Today 18% to 20% of all coronary bypass operations are performed off-pump16Mack M.J. Pro: Beating heart surgery for coronary revascularization: is it the most important development since the introduction of the heart-lung machine?.Ann Thorac Surg. 2000; 70: 1774-1778Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar; yet, there is wide variability between centers, and the whole field is subject to large swings based on new technology and new outcome studies. A standard median sternotomy is required for multivessel grafting without CPB.17Hirata N. Sawa Y. Takahashi T. et al.Is median sternotomy invasive? A comparison between minimally invasive direct coronary artery bypass and off-pump bypass.Surg Today. 2000; 30: 503-505Crossref PubMed Google Scholar Median sternotomy allows access to all potential targets, including routine access to the right or left internal mammary arteries for harvesting, and permits rapid institution of CPB should instability occur during CPB.18Ramsay J. Anesthesia for off-pump coronary artery bypass grafting.in: Clements F. Shanewise J. Minimally Invasive Cardiac Vascular Surgical Techniques. Lippincott Wiliams & Wilkins, Baltimore, MD2001: 13-28Google Scholar Minimally invasive direct coronary artery bypass (MIDCAB) to the LAD with the LIMA19Magovern J.A. Benckart D.H. Landreneau R.J. et al.Morbidity, cost and six-month outcome of minimally invasive direct coronary artery bypass grafting.Ann Thorac Surg. 1998; 66: 1224-1229Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar is performed through a left anterior short thoracotomy incision or a ministernotomy, and a right thoracotomy is used for the right internal mammary artery to the right coronary artery (RCA). Alternative incisions include partial sternotomy, the lower half of the sternum, and other incisions.20Niinami H. Takuchi Y. Suda Y. et al.Lower sternal splitting approach for off-pump coronary artery bypass grafting.Ann Thorac Surg. 2000; 70: 1431-1433Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar, 21Ricci M. Salerno T.A. Houck J.P. Manubrium-sparing sternotomy and off-pump coronary artery bypass grafting in patients with tracheal stoma.Ann Thorac Surg. 2000; 70 (769-680)Google Scholar, 22Subramanian V.A. Patel N.U. Transabdominal minimally invasive direct coronary bypass grafting (MIDCAB).Eur J Cardiothorac Surg. 2000; 17: 485-487Crossref PubMed Scopus (20) Google Scholar Cardiac displacement allows the exposure of posterior, lateral, and inferior targets and can be achieved either by the placement of deep pericardial retraction sutures or the use of stockinet sutured into the oblique sinus.23Heames R.M. Gill R.S. Ohri S.K. et al.Off-pump coronary artery surgery.Anaesth. 2002; 57: 676-685Crossref Scopus (16) Google Scholar Exposure of the LAD, its diagonal branches, or proximal RCA can be achieved with minimal displacement by placing laparotomy sponges in the pericardial sac.24Soltoski P. Salerno T. Levinsky L. et al.Conversion to cardiopulmonary in off-pump coronary artery bypass grafting Its effect on outcome.J Card Surg. 1998; 13: 328-334Crossref PubMed Google Scholar To expose the circumflex artery, its branches, the posterior descending artery, and the posterolateral branch of the RCA, a combination of maneuvers and techniques, including placement of pads, slings, pericardial sutures, or a retracting sock,24Soltoski P. Salerno T. Levinsky L. et al.Conversion to cardiopulmonary in off-pump coronary artery bypass grafting Its effect on outcome.J Card Surg. 1998; 13: 328-334Crossref PubMed Google Scholar, 25Shennib H. Bastawisy A. Coronary artery bypass grafting on the beating heart A simple technique for subluxating the heart.Ann Thorac Surg. 1999; 67: 870-871Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar, 26Rama A. Mohammadi S. Leprince P. et al.A simple method for heart stabilization during off-pump multi-vessel coronary artery bypass grafting Surgical technique and short-term results.Eur J Cardiothorac Surg. 2001; 19: 105-107Crossref PubMed Scopus (4) Google Scholar may be used (Fig 1). The heart is displaced and elevated anteriorly as a result of these maneuvers, thereby providing adequate exposure. The key to successful OPCAB grafting is effective local cardiac wall stabilization, which allows good quality anastomotic suturing. Stabilizers placed on the epicardium over the planned site of arteriotomy reduce cardiac motion either by pressure or suction devices.27Stanbridge R.D. Hadjinikolaou L.K. Technical adjuncts in beating heart surgery comparison of MIDCAB to off-pump sternotomy A meta-analysis.Eur J Cardiothorac Surg. 1999; 16: S24-S33Crossref PubMed Scopus (35) Google Scholar, 28Pavie A. Lima L. 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Off-pump versus on-pump coronary artery bypass surgery A case-matched comparison of clinical outcomes and costs.Heart Surg Forum. 2000; 3: 277-281PubMed Google Scholar This is a huge advancement from the early days, when bradycardia was induced with short-acting beta-blockers, diltiazem, or adenosine to produce a quiet anastomotic site.18Ramsay J. Anesthesia for off-pump coronary artery bypass grafting.in: Clements F. Shanewise J. Minimally Invasive Cardiac Vascular Surgical Techniques. Lippincott Wiliams & Wilkins, Baltimore, MD2001: 13-28Google Scholar, 32Chauhan S. Saxena N. Rao B.H. et al.A comparison of esmolol & diltiazem for heart rate control during coronary revascularization on beating heart.Ind J Med Res. 1999; 110: 174-177PubMed Google Scholar Several stabilizers have gained acceptance with graft patency similar to that of conventional coronary artery bypass.33Subramanian V.A. Less invasive arterial CABG on beating heart.Ann Thorac Surg. 1997; 63: S68-71Abstract Full Text PDF PubMed Scopus (110) Google Scholar The coronary artery stabilizer is placed on the epicardium, over the planned site of arteriotomy, to provide regional immobilization. The first coronary artery stabilizer to gain acceptance was the mechanical stabilizer by CardioThoracic Systems (now Guidant) or the CTS coronary stabilizer (CardioThoracic Systems, Inc, Cupertino, CA).33Subramanian V.A. Less invasive arterial CABG on beating heart.Ann Thorac Surg. 1997; 63: S68-71Abstract Full Text PDF PubMed Scopus (110) Google Scholar A motionless field is obtained by placing the mechanical platform on the epicardium at the site of the arteriotomy. The platform is fixed in position using articulating arms. One of the earlier reports using this system during anastomosis of the LIMA to the LAD yielded 96% graft patency similar to that of conventional bypass.33Subramanian V.A. Less invasive arterial CABG on beating heart.Ann Thorac Surg. 1997; 63: S68-71Abstract Full Text PDF PubMed Scopus (110) Google Scholar The Octopus Stabilization System (Medtronic, Inc) is one of the most commonly used systems, which uses suction to immobilize the surgical field between the 2 paddles, each of which has 4 to 5 suction devices.14Spooner T. Hart J.C. Pym J. A two-year, three-institution experience with the Medtronic Octopus Systematic off-pump surgery.Ann Thorac Surg. 1999; 68: 1478-1481Abstract Full Text Full Text PDF PubMed Scopus (40) Google Scholar, 34Kappert U. Gulielmos V. Knant M. et al.The application of the Octopus stabilizing system for the treatment of high-risk patients with coronary artery disease.Eur J Cardiothorac Surg. 1999; 16: S7-S9Crossref PubMed Scopus (17) Google Scholar, 35Maslow A.D. Park K.W. Pawlowski J. et al.Minimally invasive direct coronary artery bypass grafting (MIDCABG) Changes in anesthetic management and surgical procedure.J Cardiothorac Vasc Anesth. 1999; 13: 417-423Abstract Full Text PDF PubMed Scopus (11) Google Scholar The Octopus and Starfish stabilizers (Medtronic, Inc) lift the anastomotic site as opposed to depressing the site and so do not impair ventricular filling unlike the other stabilizing systems.29Nierich A.P. Diephnis J. Jansen E.W. et al.Embracing the heart perioperative management of patients undergoing off-pump coronary artery bypass using the Octopus tissue stabilizer.J Cardiothorac Vasc Anesth. 1999; 13: 123-129Abstract Full Text PDF PubMed Scopus (71) Google Scholar The Cohn Stabilizer (Genzyme, Cambridge, MA) consists of 3 pieces that are connected to either the sternal retractor (median sternotomy) or the rib retractor (thoracotomy approach). Two metal arms articulate and secure a plastic square plate to the site of arteriotomy. The square stabilizer is secured to the site via silicone elastic tapes that have been placed deep to the proximal and distal portions of the targeted coronary artery segments. After placement at the desired location, the 2 arms are cleated in place, providing a stable, motionless surgical field. To eliminate bleeding at the site, the 2 silicone elastic tapes are tightened, resulting in proximal and distal occlusion of the coronary artery.36Maslow A. Solomon A. Jacobsohn E. et al.Off-pump coronary artery bypass graft surgery. Case 6—1999.J Cardiothorac Vasc Anesth. 1999; 13: 764-781Abstract Full Text PDF PubMed Google Scholar In a prospective, randomized, controlled trial to compare the efficacy of the 2 different stabilizer concepts for OPCAB grafting, the mechanical stabilizer showed better epicardial immobilization of the anterior wall resulting in shorter anastomosis times. However, the suction device was more flexible in handling and allowed easier access to all vessels compared with the mechanical stabilizer.37Detter C. Deuse T. Christ F. et al.Comparison of two stabilizer concepts for off-pump coronary artery bypass grafting.Ann Thorac Surg. 2002; 74: 497-501Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar Hemodynamic instability is a recognized feature of OPCAB. It often occurs with coronary artery occlusion, particularly when the right coronary artery is occluded.23Heames R.M. Gill R.S. Ohri S.K. et al.Off-pump coronary artery surgery.Anaesth. 2002; 57: 676-685Crossref Scopus (16) Google Scholar Adopting a number of strategies may ameliorate this hemodynamic compromise, which may be transient with associated electrocardiogram (ECG) changes, or may result in bradycardia and asystolic arrest. Right hemisternum elevation with a specialized pericardial retractor, extensive right pleurotomy, and deep vertical right pericardiotomy are done to allow cardiac herniation into the right pleural cavity.38Suzuki T. Okabe M. Yasuda F. et al.Our experiences for off-pump coronary artery bypass grafting to the circumflex system.Ann Thorac Surg. 2003; 76: 2013-2016Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar, 39Mishra M. Shrivastava S. Dhar A. et al.A prospective evaluation of hemodynamic instability during off-pump coronary artery bypass surgery.J Cardiothorac Vasc Anesth. 2003; 17: 452-458Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar To assist further in providing good presentation of the target arteries, especially the posterior and inferior walls, patients are placed in a gentle right decubitus Trendelenburg position.18Ramsay J. Anesthesia for off-pump coronary artery bypass grafting.in: Clements F. Shanewise J. 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