This study investigates the potential benefits of off-pump coronary artery bypass grafting (OPCABG) for patients undergoing combined coronary artery bypass grafting (CABG) and valve surgery. Cardiopulmonary bypass (CPB) is a standard component of traditional on-pump CABG (ONCABG), but its prolonged use is associated with complications, including systemic inflammation, oxidative stress, and coagulation issues. OPCABG, which avoids prolonged CPB, may improve short-term outcomes for patients undergoing complex cardiac procedures.
A retrospective analysis was conducted at Beijing Anzhen Hospital on 884 patients between 2021 and 2023. Patients were divided into two groups based on the surgical technique used: 173 patients in the OPCABG group and 711 in the ONCABG group. Baseline differences in patient characteristics were addressed using propensity score matching (PSM) and inverse probability of treatment weighting (IPTW). The study evaluated key outcomes such as postoperative atrial fibrillation (POAF), acute kidney injury (AKI), stroke, operative mortality, and perioperative myocardial infarction (PMI).
The results revealed that the OPCABG group had significantly lower incidences of POAF (29.5% vs. 39.5%, p = 0.016) and AKI (14.5% vs. 21.2%, p = 0.047) compared to the ONCABG group. Logistic regression analysis confirmed that OPCABG was independently associated with a reduced likelihood of POAF (adjusted OR: 0.63, 95% CI: 0.44–0.91, p = 0.014) and AKI (adjusted OR: 0.63, 95% CI: 0.39–0.98, p = 0.049). These findings persisted even after statistical adjustments with PSM and IPTW. CPB and aortic cross-clamp times were significantly shorter in the OPCABG group, contributing to reduced myocardial injury and systemic inflammation.
No statistically significant differences were observed in operative mortality, stroke, or PMI between the OPCABG and ONCABG groups. Additionally, levels of myocardial enzymes, including CK-MB and hsTnI, were lower in the OPCABG group three days after surgery, though not significantly different from the ONCABG group. These findings suggest that OPCABG offers a safer alternative for reducing complications without negatively impacting survival rates.
The study highlights several mechanisms that may explain the benefits of OPCABG. The shorter CPB duration in OPCABG reduces myocardial ischemia and systemic inflammation, key contributors to POAF. In contrast, prolonged CPB in ONCABG increases oxidative stress and inflammatory cytokine production, potentially exacerbating complications like POAF and AKI. The findings also suggest that OPCABG minimizes renal ischemia, which can occur due to vasoconstriction during extended CPB.
Despite these promising results, the study acknowledges limitations. As a retrospective study, it is susceptible to selection biases, and the patient population may have influenced surgical decision-making. For instance, OPCABG may have been preferentially performed on patients with specific coronary anatomies or those at lower risk for complications. Additionally, the study did not evaluate long-term outcomes, such as graft patency or survival, which are critical for assessing the overall efficacy of OPCABG.
In conclusion, this study supports the use of OPCABG in combined CABG and valve surgeries, particularly for patients at higher risk of POAF and AKI. The technique reduces CPB duration, improving short-term outcomes without increasing operative mortality or stroke risk. Further randomized controlled trials are necessary to validate these findings and explore the long-term benefits of OPCABG in complex cardiac procedures.
