Background: The impact of off-pump coronary artery bypass graft surgery (OPCAB) on operative mortality compared to conventional coronary artery bypass graft surgery (CABG) with cardiopulmonary bypass (CCB) has not been clarified.
Method: Patient clinical characteristics were compared between OPCAB and CCB for isolated CABG surgeries in 2003 to 2005 using data from the California CABG outcomes reporting program. A propensity score method and logistic regression models were used to compute propensity-adjusted operative mortality for patients undergoing OPCAB or CCB.
Results: Of 57,284 isolated CABGs, 13,515 (22.9%) were OPCAB. Compared to CCB, OPCAB patients were older, more females/nonwhite, and had a higher prevalence of certain noncardiac risk factors but were fewer with diabetes, acute myocardial infarction, New York Heart Association class IV heart failure or angina, cardiogenic shock, prior cardiac surgery, left main coronary disease, or > or =3-vessel coronary disease (all P < .01). Overall, the propensity-adjusted operative mortalities (PAOMRs) were significantly lower in OPCAB patients compared to CCB patients (OPCAB 2.59% [95% CI 2.52%-2.67%] vs CCB 3.22% [95% CI 3.17%-3.27%]). Off-pump CABG had a protective advantage for all quintile subgroups (all P < .05). However, within the OPCAB cohort, those who converted to CCB intraoperately had higher PAOMR (converters 3.47% [95% CI 3.16%-3.77%] vs nonconverters 2.53% [95% CI 2.46%-2.61%]). Age, female sex, nonwhite race, diabetes, congestive heart failure, prior cadiac surgery, left main disease, and with > or =3 diseased coronary arteries were associated with a higher risk of intraoperative conversion from OPCAB to CCB (all <0.05).
Conclusion: OPCAB and CCB patients had significantly different preoperative risk profiles, and OPCAB was associated with lower operative mortality compared to CCB.