Outcomes for off-pump coronary artery bypass grafting in high-risk groups: a historical perspective.

BACKGROUND: The outcomes of off-pump coronary artery bypass (OPCAB) and conventional coronary artery bypass grafting with cardiopulmonary bypass (cCABG) have been compared in detail. Similarly, several reports have examined outcomes of high-risk subsets of patients in OPCAB as a selection strategy for reducing morbidity and mortality compared to cCABG. We undertook a retrospective study comparing outcomes from the early years in our experience of beating-heart surgery in high-risk patients selected for OPCAB compared to low-risk patients having OPCAB. This study was premised on strict selection criteria in an era prior to stabilizing devices and cardiac positioners. METHODS: A total of 384 patients underwent OPCAB over a 10-year period. Clinical outcomes were compared for 280 low-risk patients and 104 high-risk patients (redo CABG, CABG with simultaneous carotid endarterectomy, or renal insufficiency/failure). RESULTS: The high-risk group patients were significantly older than the low-risk group patients (64.3 +/- 10.5 years versus 61.5 +/- 11.7 years, respectively, P = .048). The high-risk group also had a greater degree of left ventricular dysfunction (P < .001), a higher incidence of diabetes (P = .046), and a higher proportion of patients with peripheral vascular disease (P = .009). There was no significant difference in the number of grafts created, but there was a statistical difference in the type of graft used. The high-risk group received fewer internal thoracic artery grafts (P = .005) and more saphenous vein grafts (P = .041). The high-risk group had slightly prolonged median lengths of stay in the intensive care unit (2.2 versus 1.4 days, P < .001) and hospital (11 versus 8 days, P < .001) and a higher proportion of patients requiring blood transfusions (48% versus 24%, P < .001), yet there was no significant difference in major adverse outcomes. CONCLUSIONS: In this retrospective and historical review, OPCAB was found to be equally safe in carefully selected high- and low-risk patients. These results provided for the enthusiasm and innovation to expand the usage of OPCAB in patients with coronary artery disease.

Surgical revascularization after acute myocardial infarction in patients with end-stage renal disease.

OBJECTIVE: Cardiovascular disease accounts for over 50% of deaths in patients with end-stage renal disease (ESRD). After acute myocardial infarction (AMI), hospital mortality exceeds 25%, and survival beyond 2 years is <20% for patients with ERSD. The role of coronary artery bypass grating (CABG) in the setting of an AMI in patients with ESRD remains undefined. METHODS: Three hundred and forty-two patients had preoperative ESRD (serum creatinine >2.0mg/dl or dialysis dependence) between 1995 and 2000. One hundred and nineteen patients had an AMI (<7 days) and 223 patients had a remote myocardial infarction (RMI) (>7 days) at the time of CABG. The study group, AMI, was compared to the RMI group, which served as a comparison group. RESULTS: The age (69 vs. 67 years), males (68 vs. 67%), creatinine (3.18 vs. 3.76 mg/dl, P=0.06), and preoperative dialysis (19 vs. 22%, P=0.52) were similar in either the AMI or RMI group, respectively. The frequency of diabetes, hypertension, dyslipidemia, previous myocardial infarction were common, yet not different between groups (P=NS). For either AMI or RMI group, multivessel CABG (96 vs. 94%, P=0.73), off-pump CABG (OPCAB) (22 vs. 18%, P=0.67), and arterial conduits (71 vs. 78%, P=0.42) were similar. Among postoperative events, only pulmonary complications (33.8 vs. 14.7%, P=0.049) and atrial fibrillation (48 vs. 29%, P<0.001) were more common in the AMI group. Hospital mortality was no different between the AMI and RMI groups (10 vs. 8.5%, P=0.88). CONCLUSIONS: Although patients with ESRD that have an AMI or RMI represent high risk groups, perioperative outcomes suggest that patients selected for CABG as an early treatment strategy in the setting of an AMI represents a viable therapeutic option.

Comparison of coronary bypass surgery with and without cardiopulmonary bypass in patients with multivessel disease.

BACKGROUND: Coronary artery bypass grafting can now be performed with or without cardiopulmonary bypass. Our objective was to determine whether off-pump coronary artery bypass grafting is associated with better early outcomes compared with conventional coronary artery bypass grafting. METHODS: In 4 centers with off-pump coronary surgery experience, a retrospective analysis of all coronary artery bypass grafting in a 3-year period was performed. Groups were compared to determine selection criteria, mortality, and morbidity, then computer-matched by propensity score to control for selection bias. Multivariate logistic regression identified risk factors predictive of mortality. Specific subgroups most likely to benefit were identified. RESULTS: In all, 17,401 isolated coronary artery bypass grafts were performed, 7283 (41.9%) off-pump coronary artery bypass grafts and 10,118 (58.1%) conventional coronary artery bypass with cardiopulmonary bypass. Factors determining selection of patients for off-pump coronary artery bypass grafting included female gender (55.5% vs 44.5%), preexisting renal failure (57.0% vs 43.0%), and reoperations (52.6% vs 47.4%). Operative mortality was 2.8%; off-pump coronary artery bypass grafting versus conventional coronary artery bypass with cardiopulmonary bypass (1.9% vs 3.5%, P <.001) had the same predicted risk. Of the patients with multivessel disease, 11,548 were matched by propensity scoring. Mortality was significantly less in the off-pump coronary artery bypass grafting group (2.8% vs 3.7%, P <.001). By multivariate logistic regression analysis of the matched sample, predictors for mortality were female gender (odds ratio 1.83, confidence interval 1.37-2.44), preexisting renal failure (odds ratio 2.85, confidence interval 2.64-4.95), history of stroke (odds ratio 1.74, confidence interval 1.08-2.80), previous coronary artery bypass grafting surgery (odds ratio 4.22, confidence interval 2.92-6.09), use of cardiopulmonary bypass (odds ratio 2.08, confidence interval 1.52-2.83), and recent myocardial infarction (odds ratio 2.31, confidence interval 1.68-3.22). Cardiopulmonary bypass was predictive of mortality in reoperations, female patients, and patients aged >or= 75 years. Off-pump coronary artery bypass grafting was associated with less morbidity, including reductions in blood transfusion (32.6% vs 40.6%, P <.001), stroke (1.4% vs 2.1%, P =.002), renal failure (2.6% vs 5.2%, P <.001), pulmonary complications (4.1% vs 9.5%, P <.001), reoperation (1.7% vs 3.2%, P <.001), atrial fibrillation (21.1% vs 24.99%, P <.001), and gastrointestinal complications (3.6% vs 4.8%, P =.02). CONCLUSION: In 4 centers with beating-heart operation experience, there is an overall early benefit in off-pump surgery, especially in patients traditionally considered at high risk for coronary artery bypass grafting.

Silastic drains vs conventional chest tubes after coronary artery bypass.

STUDY OBJECTIVES: To investigate differences in drainage amounts and early clinical outcomes associated with the use of Silastic drains, as compared with the conventional chest tube after coronary artery bypass grafting (CABG). DESIGN: Retrospective nonrandomized case control study. SETTING: A tertiary teaching hospital. PATIENTS AND PARTICIPANTS: Outcome data from 554 patients who underwent postoperative pericardial decompression using small Silastic drains were compared with those from 556 patients who had conventional chest tubes after first-time CABG at our institution between January 1 and August 1, 2000. MEASUREMENT AND RESULTS: Univariate analysis of preoperative characteristics was used to ensure similarity between the two patient groups. Operative mortality, mediastinitis, reoperation for bleeding, and early and late cardiac tamponade occurred in 9 patients (1.6%), 6 patients (1.1%), 6 patients (1.1%), 6 patients (1.1%), and 1 patient (0.2%), respectively, in the Silastic drain group, compared with 11 patients (2.0%), 9 patients (1.6%), 4 patients (0.7%), 2 patients (0.4%), and 6 patients (1.1%) in the conventional group. No statistically significant differences between the two drains were identified. Drainage amounts (mean +/- SD) were 552.2 +/- 281.8 mL and 548.8 mL +/- 328.7 mL for the Silastic and conventional groups, respectively (p = 0.51). Postoperative length of stay was longer for the conventional chest tube group (median, 5 d; range, 1 to 119 d) when compared to the Silastic drain group (median, 4 d; range, 1 to 66 d; p = 0.01). CONCLUSIONS: We demonstrated that small Silastic drains are equally as effective as the conventional, large-bore chest tubes after CABG with no significant risk of bleeding or pericardial tamponade. Additionally, use of Silastic drains allows more mobility than the conventional chest tubes. As a result of this study, there was a change in our clinical practice toward the exclusive use of Silastic drains after all cardiac surgical procedures.

Beating heart surgery in a patient with dextrocardia and complete situs inversus.

We present a 65-year-old female patient with dextrocardia and situs inversus who underwent successful coronary artery bypass without cardiopulmonary bypass. Vessels revascularized included right internal mammary artery to the left anterior descending artery and a saphenous vein graft to the first obtuse marginal branch. The procedure was performed on a beating heart through a median sternotomy with the use of a compression epicardial stabilizer. The patient was discharged to her home after an uneventful recovery. Only 12 similar cases of myocardial revascularization in patients with dextrocardia have been reported so far, and this is one of the first procedures, in patients with dextrocardia, performed off pump.

Clinical outcomes of coronary revascularization without cardiopulmonary bypass.

OBJECTIVE: Coronary artery bypass without cardiopulmonary bypass (OPCAB) eliminates the complications related to cardiopulmonary bypass. However, the long-term outcomes of this procedure are largely unknown. METHODS: We sought to investigate the rates of late mortality, stroke, acute myocardial infarction, and target vessel reintervention after OPCAB in a consecutive series of 857 patients who underwent OPCAB between May 1987 and March 1999. RESULTS: Long-term follow-up was obtained for 86% of eligible patients. Actuarial and event-free survival was 89% and 76%, respectively, for a median follow-up period of 2.2 years (range, 0-13.3 years). Risk factors for late mortality were identified with Cox regression analysis. In the multivariate analysis, patient age >75 years (odds ratio, 1.1; 95% confidence interval, 1.0-1.1; P =.01) and an ejection fraction <35% (odds ratio, 2.7; 95% confidence interval, 1.2-6.2; P =.02) emerged as independent predictors of late mortality. CONCLUSION: OPCAB is associated with a low mortality and clinical event rate. Advanced age and depressed ejection fraction may increase mortality after OPCAB.

Stroke after conventional versus minimally invasive coronary artery bypass.

BACKGROUND: Postoperative stroke is a serious complication after coronary artery bypass grafting with cardiopulmonary bypass (on-pump), and portends higher morbidity and mortality. It is unknown whether an off-pump cardiopulmonary bypass (OPCAB) approach may yield a lower stroke rate over conventional on-pump coronary artery bypass grafting. METHODS: From June 1994 to December 2000, OPCAB was performed in 2,320 patients and compared with 8,069 patients who had on-pump coronary artery bypass grafting, during the same period of time. The patients undergoing OPCAB were randomly matched to on-pump patients by propensity score. A logistic regression model was used to test the difference in the postoperative stroke rate between OPCAB and on-pump procedures controlling for the correlation between matched sets. A multiple logistic regression model predicting the risk of stroke adjusted by stroke risk factors and operation type was also computed. RESULTS: Matches by propensity score were found for 72% of the patients undergoing OPCAB. Patients undergoing on-pump coronary artery bypass grafting were 1.8 (95% confidence interval 1.0 to 3.1, p = 0.03) times more likely to suffer a stroke postoperatively than OPCAB patients after controlling for preoperative risk factors through matching. Independent predictors of stroke identified from the multiple logistic model included on-pump operation (versus OPCAB operation), female gender, 4 to 6 vessels grafted (versus <4 grafts), hypertension, history of previous cerebrovascular accident, carotid artery disease, chronic obstructive pulmonary disease, and depressed ejection fraction. CONCLUSIONS: Off-pump cardiopulmonary bypass avoids the risks of cardiopulmonary bypass and atrial trauma. A substantially lower stroke rate suggests that OPCAB is a neurologically safe treatment option for revascularization.

Elimination of cardiopulmonary bypass improves early survival for multivessel coronary artery bypass patients.

BACKGROUND: Coronary artery bypass graft (CABG) surgery performed without cardiopulmonary bypass (CPB) is currently increasing in clinical practice. Decreased morbidity associated with off-pump (OP) CABG in selected risk groups examined in relatively small, single institution groups has been the focus of most recent studies. The purpose of this study was to determine the independent impact of CPB on early survival in all isolated multivessel CABG patients undergoing surgery in two large institutions with established experience in OPCABG techniques. METHODS: A review of two large databases employed by multiple surgeons in the hospitals of two institutions identified 8,758 multivessel CABG procedures performed from January 1998 through July 2000. In all, 8,449 procedures were included in a multivariate logistic regression analysis to determine the relative impact of CPB on mortality independent of known risk factors for mortality. Procedures were also divided into two treatment groups based on the use of CPB: 6,466 had CABG with CPB (CABG-CPB), 1,983 had CABG without CPB (OPCABG). Disparities between groups were identified by univariate analysis of 17 preoperative risk factors and treatment groups were compared by Parsonnet's risk stratification model. Finally, computer-matched groups based on propensity score for institution selection for OPCABG were combined and analyzed by a logistic regression model predicting risk for mortality. RESULTS: CABG-CPB was associated with increased mortality compared with OPCABG by univariate analysis, 3.5% versus 1.8%, despite a lower predicted risk in the CABG-CPB group. CPB was associated with increased mortality by multiple logistic regression analysis with an odds ratio of 1.79 (95% confidence interval = 1.24 to 2.67). An increased risk of mortality associated with CPB was also determined by logistic regression analysis of the combined computer-matched groups based on OPCABG-selection propensity scores with an odds ratio of 1.9 (95% confidence interval = 1.2 to 3.1). CONCLUSIONS: Elimination of CPB improves early survival in multivessel CABG patients. Rigorous attempts to statistically account for selection bias maintained a clear association between CPB and increased mortality. Larger multiinstitutional studies are needed to confirm these findings and determine the most appropriate application of OPCABG.