Off-Pump vs. On-Pump Coronary Artery Bypass Grafting in Japan

I. IntroductionCoronary artery bypass grafting (CABG) is the standard surgical treatment for patients with coronary artery disease.Among the various surgical techniques, off-pump coronary artery bypass grafting (OPCAB), which avoids the use of cardiopulmonary bypass (CPB), has gained significant attention for its potential to reduce surgical invasiveness.OPCAB, which involves systemic inflammatory responses and organ dysfunction, was initially developed to mitigate complications associated with CPB.With the advent of stabilizing devices and other technological advancements, OPCAB has gained worldwide traction, particularly in Japan.Between 2013 and 2016, OPCAB accounted for approximately 60% of CABG cases in Japan, contrasting sharply with the United States, where the rate remained at around 15%.This highlights the significant difference in the adoption of surgical strategies between the two countries 1) .Despite its widespread adoption, the role of OPCAB remains a topic of debate.Studies from the early 2000s have highlighted its short-term benefits, including reduced stroke risk and rates of renal dysfunction and blood transfusion.However, concerns regarding incomplete revascularization, lower graft patency rates, and potentially worse long-term outcomes than on-pump CABG (ONCAB) have challenged its routine use.Randomized controlled trials (RCTs), such as ROOBY and CORONARY, failed to demonstrate consistent long-term survival benefits for OPCAB over ONCAB 2,3) , further fueling controversy regarding its routine use.The Japanese Cardiovascular Surgery Database (JCVSD) plays a pivotal role in addressing these clinical uncertainties.Established in 2001, the JCVSD provides comprehensive nationwide data on cardiovascular surgeries including CABG.Utilizing this robust registry, several studies have compared the outcomes of OPCAB and ONCAB in diverse patient populations [4][5][6][7][8][9] .These studies focused on high-risk cohorts, such as those with chronic kidney disease (CKD) or left ventricular dysfunction, highlighting the Review ArticleOff-Pump vs. On-Pump Coronary Artery Bypass Grafting in Japan: Insights from the Japanese Cardiovascular Surgery Database Chikara Ueki 1, 2*Coronary artery bypass grafting is a well-established treatment for coronary artery disease, and avoiding cardiopulmonary bypass has attracted attention because of its potential to reduce complications.Japan was an early and extensive adopter of off-pump coronary artery bypass grafting, offering a unique environment to evaluate its outcomes.Using data from the Japanese Cardiovascular Surgery Database, several large-scale observational studies have compared off-and on-pump coronary artery bypass grafting in diverse patient populations.These studies consistently revealed a lower early mortality with the off-pump technique than on-pump, especially in high-risk groups, such as those with severe renal disease or an impaired left ventricular function.However, concerns persist regarding the completeness of revascularization and the higher likelihood of fewer bypass grafts when performing off-pump surgery than on-pump, which may limit the long-term benefits.Analyses focusing on the long-term survival found no definitive advantage of the off-pump strategy, with some evidence suggesting worse outcomes in patients with incomplete revascularization than in others.Furthermore, the experience level of surgeons and hospital procedure volume have emerged as critical factors influencing the success of off-pump surgery, highlighting the importance of technical proficiency.Overall, although the off-pump approach provides meaningful advantages for select high-risk populations, its routine application remains controversial.Future research efforts should target improved selection criteria and broader data integration to establish more definitive conclusions and optimize patient outcomes.