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Early benefits of off-pump CABG versus conventional CABG not maintained long term in elderly patients, researchers report

Thursday, October 09 2008 | Comments

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What's This? Although off-pump coronary artery bypass (OPCAB) grafting is associated with favorable early outcomes as compared with conventional coronary artery bypass grafting (CCABG) in elderly patients, a recent study indicates that it may lead to worse long-term results.

To investigate the difference in outcomes between OPCAB, which does not require cardiopulmonary bypass and thus avoids the related potential side effects, and CCABG, researchers analyzed data for 1,191 consecutive patients aged >65 years who underwent OPCAB (n=447) or CCABG (n=744) between January 1999 and December 2003.

The researchers assessed early outcomes, including in-hospital mortality and postoperative morbidities, and long-term outcomes, including total mortality, repeat revascularization, Q-wave myocardial infarction, stroke, and rates of readmission. The median follow-up was 46.9 months.

To adjust for procedure selection bias, a propensity-matched analysis was performed in which the significant predictors of surgery type were used to match each patient in the OPCAB group with a patient in the CCABG group who had the same set of predictors. In all, 610 patients were matched.

The patients in the OPCAB group were significantly older than those in the CCABG group (mean age, 70.04 vs 69.10 years; P<.001), and they also had a higher incidence of peripheral vascular disease (15.4% vs 6.6%; P<.001), a higher EuroSCORE (4.01 vs 3.59; P<.001), greater use of internal thoracic artery graft (94.9% vs 91.7%; P=.039), a higher rate of incomplete revascularization (16.3% vs 3.2%; P<.001), and more arterial distal anastomoses (1.00 vs. 0.94; P=.006).

The patients in the CCABG group, however, had a higher prevalence of triple vessel disease (88.4% vs 83.9%), a higher ratio of grafts to diseased vessels (1.34 vs 1.10), and more venous distal anastomoses (2.89 vs 2.03; P<.001 for all).

Overall, the in-hospital mortality rate was low (2.18%). No significant between-group differences were observed for this outcome or for postoperative hospital stay.

Regarding early outcomes, a univariate analysis revealed that OPCAB conferred significant benefits in terms of pulmonary and infective complications, length of intensive care unit stay, stroke, new renal failure, intraaortic balloon pump use, inotrope use, and low cardiac output syndrome. In a multivariate analysis, the adjusted odds ratios still favored OPCAB for pulmonary complications (OR, 2.6), low cardiac output syndrome (OR, 1.6), reoperation (OR, 2.3), and infective complications (OR, 3.6).

In the long term, however, stroke, major adverse cardiac and cerebrovascular events (MACCEs), and readmission occurred with greater frequency in the OPCAB group than in the CCABG group (P<.001 for all). In addition, there was a nonsignificant trend toward higher mortality (P=.193) and higher repeat revascularization rates (P=.067) with OPCAB.

The study authors also noted that, intraoperatively, the off-pump procedure was a significant predictor of stroke (HR, 2.6), readmission (HR, 2.0), and MACCEs (HR, 1.764).

"The most important result of our study is that despite more favorable early outcomes, the benefits of OPCAB cannot be maintained in the long term," the authors concluded, calling for a large, randomized trial to confirm the influence of OPCAB on long-term outcomes in this population. (Li Y, et al. J Thorac Cardiovasc Surg 2008;136:657-664.)

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