Intraoperative conversion from off-pump to on-pump coronary artery bypass is associated with increased 30-day hospital readmission

Background: We evaluated the impact of intraoperative conversion from off-pump coronary artery bypass graft surgery (OPCAB) to conventional coronary artery bypass graft surgery (CABG) with cardiopulmonary bypass (CCB) on rates of postoperative 30-day hospital readmissions.

Methods: Using data from the California CABG outcomes reporting program, postoperative 30-day hospital readmissions were compared among CCB, OPCAB, and intraoperative conversions from OPCAB to CCB (IOC) for isolated CABG operations. A multivariable logistic regression model with inverse propensity for OPCAB weighting was used to compute risk-adjusted readmission rates. General linear models were used to test the differences in propensity-weighted and risk-adjusted readmission rates among CCB, OPCAB, and IOC cases.

Results: Among 22,389 isolated CABGs, 5,125 (22.9%) were OPCAB; 595 (11.6%) OPCAB patients had intraoperative conversion from OPCAB to CCB (IOC). The patients who underwent IOC had a higher prevalence of preoperative heart failure, left main coronary artery disease, and 3 or greater diseased coronary vessels compared with OPCAB without conversion. The risk-adjusted readmission model (weighted for OPCAB propensity) showed OPCAB without conversion was not associated with any increase in readmission rates when compared with CCB (adjusted odds ratio [AOR]; 1.02, 95% confidence interval [CI], 0.963 to 1.081) but OPCAB with IOC had a significant effect on readmission (AOR, 1.258; 95% CI, 1.122 to 1.411, p<0.0001). The OPCAB with IOC was also associated with a higher proportion of readmissions due to postoperative infection (19.1% vs 11.9% of readmissions for CCB).

Conclusions: Intraoperative conversions from OPCAB to CCB are associated with a higher rate of postoperative hospital readmission and infection.