Purpose: Previous publications have documented that off-pump coronary artery bypass graft (CABG) procedures cost less than on-pump. Historically, our US-based, multicenter, randomized, controlled trial found no clinical outcome advantage for off-pump CABG. Thus, a cost-effectiveness analysis (CEA) was performed to compare off-pump vs. on-pump patients’ 1-year health care quality-adjusted life years and costs.
Methods: Multivariate CEA regression models estimated 1-year costs (standardized to 2010 dollars), while controlling for site and patient factors (i.e., age, sex, race, marital status, insurance, smoking, depression, aorta quality, graft count, and preoperative length of stay). The 1-year incremental CEA ratio with 95% confidence intervals was calculated using bootstrapping.
Results: At 18 centers, 2,203 participants were randomized to on-pump (n = 1,099) vs. off -pump (n = 1,104) CABG procedures. No differences were found for 1-year quality-adjusted life years; both groups improved significantly after surgery (p < 0.01) as compared to baseline. Adjusted cost of the index CABG hospitalization was $36,046 on-pump and $36,536 off -pump (p = 0.16). At 1 year, on-pump adjusted cost was $56,023 vs. $59,623 off -pump (p = 0.046). Occurring after placement of the first distal anastomosis (4.8% of off -pump CABG), off-to-on-pump conversions had significantly higher 1-year costs. Excluding conversions, there were no significant differences between treatments for the index hospitalization or 1-year total costs.
Conclusions: Off-pump CABG was more expensive than on-pump when late conversions were included at 1 year. Excluding late conversions, neither costs nor quality-adjusted life years were different. When off-pump CABG is performed with minimal conversions, neither approach has a clear economic advantage. Future research evaluating the potential of a CEA benefit for higher risk off-pump patients appears warranted.