Initial experience with off-pump coronary artery bypass grafting

Using decision-analysis and meta-analysis to predict coronary artery bypass surgical outcomes – a model for comparing off-pump surgery to miniaturized cardiopulmonary bypass circuits

Coronary artery bypass (CABG) surgery with cardiopulmonary bypass (CPB) has been the “gold standard” for many years. However, methods to conduct off-pump coronary artery bypass (OPCAB) surgery with a beating heart have decreased the use of CPB. Improvements in cardiopulmonary bypass technology, using low-prime circuits with retrograde autologous prime, have demonstrated a reduction in blood use while maintaining the surgical advantage of increased revascularization associated with on-pump surgery. A meta-analysis of published randomized clinical trials was used to compare the outcomes. These outcomes included the number of grafts, hospital length of stay, and transfusion rate. They were then incorporated into a decision-analysis model to compare OPCAB with the on-pump surgery, using both conventional high-prime (HP) and low-prime circuits with retrograde autologous prime (LP/RAP). The meta-analysis of randomized clinical trials revealed that OPCAB surgery had 0.33 less grafts (p < .05), a reduction of 0.97 days in hospital length of stay (LOS) (p < .05), and a 63.2% reduction in percentage of patients transfused (p < .05). Based on the decision-analysis model, a relatively low major event rate (defined as myocardial infarction, need for angioplasty or surgery) at 4 years of 2% can eliminate the savings associated with OPCAB when compared to a low-prime circuit with RAP. Using a 5% major event rate at 4 years, the predicted cost savings of LP/RAP over OPCAB is $510 per patient or $51,036,746 per 100,000 patients. The development and implementation of low-prime circuits with retrograde autologous prime is an import step in matching the outcomes associated with OPCAB surgery.

The real-world outcomes of off-pump coronary artery bypass surgery in a public health care system

BACKGROUND

The population-based results of off-pump coronary artery bypass surgery (OPCAB) in a public health care system have not been reported.

OBJECTIVE

The study objective was to compare the one-year outcomes of OPCAB with those of the standard on-pump coronary artery bypass surgery (ONCAB) in the province of Ontario.

METHODS

The present study was a retrospective, population-based study (n=15,172, with 1660 OPCAB patients) undertaken in fiscal years 2000 and 2001 using clinical and administrative data. Multivariate regression modelling for risk adjustment and propensity matching were used to compare OPCAB with ONCAB for one-year outcomes, including death, repeat revascularization and cardiac readmission.

RESULTS

The rate of OPCAB was 11%, with institutional rates ranging from 3% to 51%. OPCAB patients were more likely to be female and older than 79 years of age, with peripheral vascular disease and higher socioeconomic status. OPCAB patients were less likely to have surgically significant coronary disease, poor left ventricular function, an urgent status, congestive heart failure and diabetes. The risk-adjusted one-year composite outcome was higher for OPCAB (11.8%, 95% CI 10.40% to 13.29%) than ONCAB (10.8%, 95% CI 10.23% to 11.27%); however, this difference was eliminated with propensity matching. OPCAB patients had shorter hospital lengths of stay and lower blood product transfusion rates than ONCAB patients.

CONCLUSIONS

Despite the minimal use of OPCAB in Canada's public health care system, outcome rates are similar to those of ONCAB. The benefits of OPCAB observed in randomized trials, including shorter hospital lengths of stay and lower transfusion rates, remained true in the investigators' real-world experience. The results OPCAB were at least equivalent to those of ONCAB.