Operative mortality and stroke after on-pump vs off-pump surgery in high-risk patients: an analysis of 83 914 coronary bypass operations

OBJECTIVES: The objective of this study was to compare the early outcomes of off-pump and on-pump surgeries in high-risk patient groups. METHODS: The outcomes of 83,914 high-risk patients undergoing off-pump or on-pump isolated coronary bypass surgery identified from the Nationwide Inpatient Sample from 2005 to 2010 were compared using propensity analysis. RESULTS: Off-pump surgery was associated with a significant reduction in stroke rates compared with on-pump surgery in propensity-matched patients ≥ 80 years (odds ratio [OR] 0.70, 95% confidence interval [CI] 0.52-0.93, P = 0.02), those with peripheral vascular disease (OR 0.53, 95% CI 0.36-0.77, P = 0.001) and those with aortic atherosclerosis (OR 0.30, 95% CI 0.13-0.72, P = 0.007). In these high-risk subgroups, off-pump surgery was associated with an absolute risk reduction in stroke rates of 0.5, 0.5 and 1.2%, respectively: the minimum number needed to treat to prevent one stroke is 200 patients. There was no significant difference in in-hospital mortality or the incidence of postoperative renal failure or respiratory failure between off-pump and on-pump surgeries in these patient subgroups, or in patients with preoperative renal failure, or chronic obstructive airways disease. CONCLUSIONS: High-risk patients undergoing coronary artery bypass surgery gain a short-term benefit from off-pump approaches due to a small absolute reduction in the risk of postoperative stroke.