Off-pump Coronary Artery Revascularization Research Articles

Comparison of On-Pump or Off-Pump Coronary Artery Revascularization With Lung Resection

The simultaneous occurrence of coronary artery disease and lung cancer is rare. The best surgical treatment strategy remains controversial: performing a combined procedure with or without the use of extracorporeal circulation (ECC). The aim of this study was to compare the surgical procedure, postoperative complications, and survival of combined surgery with the use of ECC to combined surgery without ECC. Forty-three patients underwent a combined procedure between 1994 and 2005. Twenty-eight patients (25 male and 3 female; mean age, 66 years; range, 54 to 76 years) underwent coronary artery (CA) revascularization with ECC after the lung resection was carried out (on-pump). Fifteen patients (14 male and 1 female; mean age, 71 years; range, 50 to 79 years) had first CA revascularization without ECC followed by lung resection (off-pump). Survival was estimated by the Kaplan-Meier method and analyzed using the log-rank test and the Cox proportional hazard regression model. Postoperative complications and hospital survival were not significantly different between groups. However, in the on-pump group late survival was significantly better. Late survival was significantly longer in patients without recurrent vessel disease and with stage I lung cancer. These results show no significant difference in using an on-pump or off-pump technique to perform a combined cardiac and lung surgery in relation to postoperative complications and hospital survival. However, our data show a significantly longer late survival period in the on-pump group. Because the off-pump patients were older and had more advanced lung malignancy, the off-pump technique should be continued and evaluated.

Coronary Artery Revascularization (CARE) Registry: An Observational Study of On-Pump and Off-Pump Coronary Artery Revascularization

The Coronary Artery Revascularization (CARE) study is a multicenter observational registry of coronary revascularization by percutaneous and surgical techniques. As a substudy of this registry, we analyzed the current practice and outcomes of on-pump and off-pump coronary artery bypass graft (CABG) surgery. Procedural and outcomes data were prospectively collected for all patients undergoing isolated CABG in eight community-based hospitals in the HCA Hospital System between February 1 and July 31, 2004. Twelve-month follow-up was obtained by patient contact, phone, questionnaire, and the National Death Index. Isolated coronary artery revascularization procedures were done in 1251 patients, with 12-month follow-up data available on 1149 (91.8%); 654 patients (52.3%) were operated on-pump and 597 (47.7%) had off-pump procedures. On-pump versus off-pump results were mean number of grafts, 3.4 +/- 1 versus 2.9 +/- 1.2 (p < 0.001); operative mortality, 1.7% versus 1.7% (p = 1.00); permanent stroke, 0.9% versus 0.7% (p = 0.51); reoperation for bleeding, 2.6% versus 1.0% (p = 0.037); prolonged ventilation, 10.0% versus 3.4% (p < 0.001); atrial fibrillation, 23.8% versus 14.9% (p < 0.001); need for transfusion, 51.0% versus 34.9% (p < 0.001); intensive care unit length of stay, 68.1 +/- 97.0 hours versus 59.3 +/- 109.4 hours (p = 0.16); and hospital length of stay, 7.5 days versus 6.2 days (p < 0.001). At 12 months, there was no difference in total cardiac mortality on-pump versus off-pump (4.9% versus 4.6%, p = 0.88), myocardial infarction (1.0% versus 0.7%, p = 0.76), need for repeat revascularization (2.8% versus 4.1%, p = 0.70), or total overall major adverse cardiac outcomes (8.7 versus 9.4, p = 0.69). Current approaches to coronary revascularization using both on-pump and off-pump techniques at individual surgeon discretion, which varies significantly in the community setting, leads to acceptable outcomes. Although perioperative complications were less off-pump, mortality was the same, both in the perioperative period and at 12 months. Fewer grafts in the off-pump group appeared to be related to disease burden and not incomplete revascularization. Cardiac death, myocardial infarction, and the need for repeat revascularization were equal at 12 months.

Off-Pump Coronary Revascularization: Operative Technique

Off-pump coronary artery bypass grafting can be performed in most patients undergoing surgical myocardial revascularization. The selection of patients for off-pump surgery is dependent on the surgeon’s knowledge and comfort with the techniques of off-pump revascularization. Early in a surgeon’s experience with off-pump revascularization, it is best to select patients with normal left ventricular size and function, relatively large epicardial coronary arteries free of diffuse calcific atherosclerosis, and coronary artery disease limited to the left anterior descending and right coronary artery systems. As the surgeon gains experience and confidence with off-pump techniques, patients with decreased left ventricular function, enlarged hearts, and coronary artery disease of the circumflex system may be performed off-pump. When the surgeon has mastered the techniques of off-pump coronary surgery, nearly all patients presenting for coronary revascularization may be considered, including those with severe left main coronary artery stenosis, poor left ventricular function, and intramyocardial coronary arteries. Relative contraindications to off-pump myocardial revascularization include patients with severely enlarged and dysfunctional hearts, mitral insufficiency, or small and diffusely diseased coronary arteries. Patients with hemodynamic instability and those with chest anatomy that prevents rightward displacement of the heart, such as pectus excavatum or previous left pneumonectomy, should not be selected for off-pump revascularization. Similar to on-pump coronary artery bypass grafting, off-pump myocardial revascularization is a complex operation composed of many steps. The operative steps of off-pump coronary artery revascularization are (1) incision and conduit preparation; (2) patient positioning; (3) target vessel exposure; (4) target vessel stabilization; (5) target vessel hemostasis and ischemia prevention; (6) construction of anastomoses; and (7) closure. Off-pump myocardial revascularization has the potential benefit of lowering the risk of coronary surgery by eliminating cardiopulmonary bypass and ascending aortic manipulation. The use of in situ and composite arterial grafts for coronary revascularization avoids the need for ascending aorta manipulation to construct proximal anastomoses. In this article, the techniques used in off-pump, multivessel coronary artery bypass grafting with in situ and composite arterial grafts is illustrated. Using these techniques of coronary artery exposure and stabilization, off-pump coronary revascularization can be performed safely and accurately in the majority of patients presenting for surgical revascularization. Whether off-pump revascularization lowers the risk of surgical revascularization has been a highly debated and controversial issue in coronary surgery during the last decade. Off-pump revascularization has the potential for lowering the risk of coronary surgery by eliminating cardiopulmonary bypass, and all arterial off-pump revascularization using in situ and composite grafts has the potential to further reduce risk by eliminating the need for aortic manipulation.

Successful Use of Recombinant Hirudin and Its Monitoring by Ecarin Clotting Time in Patients with Heparin-Induced Thrombocytopenia Undergoing Off-Pump Coronary Artery Revascularization

Refludan (lepirudin-rDNA for injection) is the first direct thrombin inhibitor approved by the United States FDA for anticoagulation to patients with heparin-induced thrombocytopenia (HIT). It was monitored by ecarin clotting time (ECT) assay in patients with HIT. Case histories and clotting parameters for three patients undergoing off-pump coronary artery revascularization procedure are discussed. The first patient received r-hirudin at a dose of 0.2 mg/kg intravenous (IV) bolus followed by 0.15 mg/kg/hour infusion. The second patient received 0.4 mg/kg IV bolus followed by infusion of 0.15 mg/kg/hour infusion. The third patient with renal failure received 0.2 mg/kg IV bolus followed by an infusion of 0.02 mg/kg/hour. Blood samples were drawn at baseline, 5 minutes post bolus and every 15 minutes during the coronary artery revascularization procedure. ECT was performed immediately on the citrated whole blood samples using the ECT cards in conjunction with the point-of-care, the thrombolytic assessment system (TAS) Analyzer (Pharmanetics, Raleigh, NC). The plasma samples were then analyzed for APTT and liquid ECT assay performed on a kinetic centrifugal analyzer (ACL 300 Plus). The ECT by cards was ideally maintained above 600 seconds during the surgical procedure. Additional boluses of Refludan were given as and when necessary (ECT < 600 sec) in order to maintain adequate anticoagulation. The calculated circulating concentrations of Refludan, following a bolus administration, based on the ECT cards, liquid ECT and APTT were 3.20 +/- 1.3, 3.51 +/- 1.35 and 2.02 +/- 1.19 microg/mL, respectively.

Unplanned left ventricular assist device insertion after elective low-risk off-pump coronary artery revascularization

ALTHOUGH CORONARY artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB) and cardioplegic arrest remains the gold standard for myocardial revascularization, the morbidity associated with it is not insignificant. In an effort to reduce morbidity associated with CPB, off-pump CABG (OPCAB) surgery is becoming increasingly popular. However, no large prospective controlled randomized trial has compared long-term graft patency and the morbidity and mortality of OPCAB versus CABG with CPB. Despite a lack of large rigorously conducted clinical trials, OPCAB is alleged by many clinicians to be as safe1-5 or safer than6-10 conventional CABG with CPB. The authors report the case of a low-risk patient who required unplanned insertion of a left ventricular assist device (LVAD) after elective OPCAB surgery.

The evolution of training in Off-Pump coronary surgery in a single institution

Background This study analyses the development of off-pump coronary artery bypass (OPCAB) surgery training at a single institution, and compares the early and midterm clinical outcomes of OPCAB and conventional coronary artery bypass grafting (CABG) procedures performed by trainees with or without direct consultant cardiothoracic surgeon supervision. Methods Analysis was undertaken on data prospectively recorded on a computer database (Patient Analysis and Tracking System). Of the 2,422 CABG operations performed between January 1999 and December 2001, 969 (40%) were carried out by trainees either off pump (422) or on pump (547). Results Although the total number of CABG operations performed by trainees remained constant, there was a significant increase in the number of OPCAB operations during the study period compared with conventional CABG, as well as an increase in the average number of grafts per patient in the OPCAB group (both p < 0.05). Furthermore, a significant trend towards using two or more arterial conduits in the OPCAB group was observed in the study period. The number of OPCAB operations performed by trainees as independent operators without direct consultant supervision also increased significantly ( p < 0.05). Early and midterm clinical outcomes were similar between patients operated by trainees on pump or off pump as independent operators versus under direct consultant supervision. Conclusions The significant increase in OPCAB operations performed by trainees as independent operators or under direct consultant supervision, as well as the increase in the number of grafts per patient and arterial conduits used for myocardial revascularization, demonstrate a progression of training in beating heart surgery for cardiothoracic trainees. Improvements in the techniques have made it safe to teach trainees off-pump multivessel coronary artery revascularization.

Combined Endovascular Treatment of a Descending Thoracic Aortic Aneurysm and Off-Pump Myocardial Revascularization

Endovascular intervention is an alternative form of treatment for patients with thoracic aortic aneurysms. Coexistent cardiovascular diseases may adversely influence the postoperative course and affect the long-term prognosis. The case of a 76-year-old man with severe coronary artery disease and a thoracic aortic aneurysm is reported. A single-stage procedure of off-pump coronary artery revascularization and endoluminal exclusion of the descending thoracic aortic aneurysm was performed. The patient was treated first with off-pump coronary artery bypass graft (left internal mammary artery on the left anterior descending coronary artery and two single venous grafts from ascending aorta to obtuse marginal artery and posterior descending artery). After heart revascularization, two Thoracic Excluder endovascular grafts (34 x 100 and 37 x 100 mm) were implanted to treat the descending thoracic aortic aneurysm. Follow-up with computed tomography angiography showed successful exclusion of the thoracic aneurysm 12 months after the procedure. The patient is well and free of symptoms 18 months later.

Off-pump coronary operations can be safely taught to cardiothoracic trainees

Background. Off-pump coronary artery bypass (OPCAB) operations are evolving rapidly and becoming established in many cardiothoracic centers. For the technique to be widely applicable, teaching methods must be developed for surgical trainees. Early and midterm clinical outcomes of OPCAB performed at our institution by trainees as first operators under supervision were compared to those obtained in patients operated on by consultants. Methods. Analysis was undertaken on data prospectively inserted in the Patient Analysis & Tracking System. Of the 559 OPCAB operations performed between January 1997 and May 2000, 124 (22%) were carried out by a supervised trainee and 435 (78%) by a consultant. Results. There was no difference in age, sex, angina class, New York Heart Association functional class, or operative priority and extent of coronary artery disease in the two groups. More patients operated on by consultants had a history of congestive heart failure requiring medical therapy, significantly lower ejection fraction, and higher Parsonnet score compared with patients operated on by trainees. Early and midterm clinical results, in terms of morbidity and mortality, were similar in patients operated on by trainees or by consultants. Conclusions. Our data show no differences in early and midterm clinical outcome for patients undergoing OPCAB operations performed either by consultants or by trainees under supervision. The improvements in exposure and stabilization techniques, as well as the use of intracoronary shunts, have made it possible and safe to teach trainees off-pump multivessel coronary artery revascularization.

Experimental off-pump coronary artery revascularization with adenosine-enhanced reperfusion

Objective: Although beating heart coronary artery bypass grafting has recently gained popularity, it eliminates the protective strategies (ie, cardioplegia) developed for use in conventional cardiac operations. We recently introduced the technique of perfusion-assisted direct coronary artery bypass to perfuse the grafted vessels during multivessel off-pump coronary artery bypass grafting. In the present study we tested the hypothesis that intracoronary reperfusion with the cardioprotective agent adenosine during simulated perfusion-assisted direct coronary artery bypass attenuates reperfusion injury. Methods: In anesthetized dogs the heart was exposed, and the left anterior descending coronary artery was ligated for 75 minutes. Reperfusion was achieved through a catheter in the left anterior descending coronary artery by means of a computer-controlled pump. Intracoronary left anterior descending coronary artery perfusion pressure was continuously matched to mean arterial blood pressure. In one group (adenosine group) 10 μmol/L adenosine was added to the blood during the first 30 minutes of reperfusion, whereas another group (vehicle group) received a comparable volume of saline solution. Results: During the first 30 minutes of reperfusion, blood flow through the left anterior descending coronary artery was significantly greater (P <.05) in the adenosine group than in the vehicle group (150.6 ± 21.9 vs 50.2 ± 11.3 mL/min at 15 minutes of reperfusion). Although there were no group differences in postischemic wall motion, infarct size was significantly smaller in the adenosine group than in the vehicle group (11.1% ± 3.0% vs 28.0% ± 4.0% of area at risk, P <.05). Myeloperoxidase activity in the necrotic tissue, an index of neutrophil accumulation, tended to be lower in the adenosine group than in the vehicle group (58.6 ± 14.2 vs 91.0 ± 21.6 ΔAbsUnits · min–1 · g–1 tissue). In isolated postischemic left anterior descending coronary artery rings, the maximal relaxation response to the endothelium-dependent vasodilator acetylcholine was significantly greater in the adenosine group than in the vehicle group (97.9% ± 5.6% vs 64.7% ± 6.5%, P <.05). Conclusion: This novel reperfusion strategy for off-pump coronary artery bypass grafting can be used not only in cases requiring multiple grafting but also to attenuate necrosis and endothelial dysfunction in acute evolving infarction. (J Thorac Cardiovasc Surg 2001;121:570-9)

Systematic off-pump coronary artery revascularization in multivessel disease: Experience of three hundred cases

Objective: We sought to report our recent experience with off-pump coronary artery revascularization in multivessel disease. Methods: Between October 1996 and December 1998, 300 off-pump beating heart operations were performed at the Montreal Heart Institute by a single surgeon, representing 94% of all procedures undertaken during this same time frame (97% for 1998). This cohort of patients was compared with 1870 patients operated on with cardiopulmonary bypass from 1995 to 1996. Results: Mean age, sex distribution, and preoperative risk factors were comparable for the two groups. On average, 2.92 ± 0.8 and 2.84 ± 0.6 grafts per patient were completed in the beating heart and cardiopulmonary bypass groups, respectively. A majority of patients (70%) had either a triple or quadruple bypass. Coronary anastomoses were achieved with myocardial mechanical stabilization and heart “verticalization.” Ischemic time was shorter in the beating heart group (29.8 ± 0.9 vs 45 ± 0.4 minutes, P < .05). Similarly, the need for transfusion was significantly less in the beating heart group (beating heart operations, 34%; cardiopulmonary bypass, 66%; P < .005). Reduced use of postoperative intra-aortic counterpulsation, as well as a lower rise in creatine kinase MB isoenzyme, was observed in the beating heart group. Operative mortality rates (beating heart operations, 1.3%; cardiopulmonary bypass, 2%) and perioperative myocardial infarction (beating heart operations, 3.6%; cardiopulmonary bypass, 4.2%) were comparable for the two groups. Conclusion: In a majority of patients, off-pump complete coronary artery revascularization is an acceptable alternative to conventional operations, yielding good results given progressive experience, rigorous technique, and adequate coronary artery stabilization. (J Thorac Cardiovasc Surg 2000;119:221-9)

Systematic off-pump coronary artery revascularization: experience of 275 cases

Background. The author reports his short-term experience with systematic off-pump coronary artery revascularization in multivessel disease. Methods. Between September 1996 and October 1998, 275 off-pump revascularizations (83% of case load during this period; 97% since January 1998) were performed by a single surgeon (R.C.). The patient base of 216 men/59 women averaged 63 ± 10 years. Main indication was unstable angina (60%). All surgeries were performed through a median sternotomy, with mechanical stabilization, and a heart “verticalizing” technique to enable access to the circumflex territory. Results. An average of 2.91 ± 0.83 (range 1 to 5) grafts/patient was achieved, with 70% of cases being triple or quadruple bypasses. Single or double internal thoracic arteries was utilized in 95% of cases. Complete revascularization was attained in 93% of surgeries. Total ischemic time averaged 28 ± 10 (range 8 to 65) minutes. Myocardial infarction incidence was 4%, with only 1 patient requiring postoperative aortic counterpulsation assistance. One early percutaneous transluminal coronary angioplasty was needed to restore an occluded posterior descending artery. Three operative deaths resulted. One conversion to cardiopulmonary bypass was required. A transfusion rate of 32% was observed, half the rate of conventional coronary artery bypass grafting at our institute. Conclusions. With gradual experience, proper operative technique, and surgical apparatus, beating heart bypass surgery may be used systematically as a suitable, safe alternative to conventional on-pump coronary artery bypass grafting, permitting complete revascularization in a majority of patients with excellent short-term results.