On-pump versus off-pump coronary artery bypass surgery: Cost-effectiveness analysis alongside a multisite trial

Background: Questions have been raised about the costs and outcomes for patients receiving on-pump and off-pump coronary artery bypass graft surgery. As part of the Department of Veterans Affairs Randomized On/Off Bypass (ROOBY) multisite trial, a cost-effectiveness analysis was performed to compare on-pump versus off-pump patients' quality-adjusted life-years and costs at 1 year. Methods: One-year outcomes and costs (standardized to 2010 dollars) were estimated in multivariate regression models, controlling for site and baseline patient factors. The 1-year incremental cost-effectiveness analysis ratio with 95% confidence intervals was calculated using bootstrapping. Results: Eighteen centers randomly assigned 2,203 participants to on-pump (n = 1,099) versus off-pump (n = 1,104) coronary artery bypass graft surgery. Both groups' quality of life improved significantly after surgery (p < 0.01) compared with baseline, but no differences were found between treatment groups. Adjusted cost of the index coronary artery bypass graft surgery hospitalization was $36,046 on-pump and $36,536 off-pump (p = 0.16). At 1 year, on-pump adjusted cost was $56,023 versus $59,623 off-pump (p = 0.046). Off-pump-to-on-pump conversions after first distal anastomosis (4.8%) had significantly higher 1-year costs. Excluding conversions, there were no significant differences between treatments for index hospitalization or 1-year total costs. Conclusions: At 1 year, off-pump coronary artery bypass graft surgery was more expensive than on-pump when late off-pump-to-on-pump conversions were included. Excluding late conversions, there was no difference in quality-adjusted life-years or costs.