Discussion
To the best of our knowledge, this study provides an up-to-date and unique view of the association between preoperative LVEF and long-term outcomes in patients after OPCAB surgery. In present study, we performed a propensity score matching using a single-center surgery registry data to investigate the disparities of long-term survival between LVD and NLVF group, and the main findings of our study were as follows: 1) The proportion of perioperative inotrope usage were significantly greater in LVD group than NLVF patients, while the proportion of constructed three or more distal anastomoses were more in NLVF group, indicating the surgery management was more challenging for LVD patient intra-OPCAB; 2) the risk of post-operative left heart failure was higher in LVD patient, compared with NLVF patients, and 3) both early postoperative and long-term outcomes are similar regardless of preoperative LVEF. These findings confirm the efficacy and safety of OPCAB utilization in patients with reduced left ventricular ejection fraction. Furthermore, these findings highlight the importance of initiatives to develop a tailored surgery strategy for patients with LVD that is able to improve surgical outcomes and optimize the long-term survival.
With the highly prevalent of coronary artery disease globally, and increasing of comorbid with impaired LVEF, cardiac surgeons are facing more patients with poor pre-condition. LVEF is the most widely used clinical indicator of left ventricular systolic function and related the cardiovascular risk in patient with heart failure. Results from CHARM showed the risk of all-causes mortality and major cardiovascular event were inversely and linearly associated with LVEF [16]. The risk of stroke was more than doubled in patients with LVEF<15% [17]. OPCAB surgery avoids ischemic cardiac arrest during coronary artery revascularization. A recent published study shows that OPCAB is a safe and efficient choice for high risk patients with multiple organs failure [18]. Given the improvement and advantages of OPCAB procedure, more and more surgeons try to extend the suegery to high risk patients, including female and Low LVEF patient [19, 20].
Despite enthusiasm for OPCAB on the part of surgeons, widespread adoption in China has been slower than anticipated. It is due, in part, to a lack of definitive evidence whether OPCAB can be safe in LVD patients. In a recent randomized control study, OPCAB and on-pump techniques seemed to produce equivalent results, although OPCAB was associated with a lower graft patency rate [21]. Given the inconsistency of different report, the usage of OPCAB in LVD patients is limited in real practice.
The major concern is high proportion of completed revascularization, which reported to be an independent risk for all-cause mortality (HR=1.8) [22]. ROOBY study and a meta-analysis demonstrated that number of constructed distal anastomoses underwent OPCAB are lesser than those underwent conventional CABG [14, 23]. Our study is in line with above findings: the lower LVEF, the smaller proportion of constructed 3 or more distal anastomoses (77.5% vs 92.5%,p =0.037). Meanwhile, the occurrences of complete revascularization are not significantly different between groups (82.5% vs 87.5%, p =0.579). Preoperative IABP and using vascular shunt during operation to construct distal anastomoses can help patients with reduced LVEF to complete revascularization. Our results have significant implications for clinical practice. OPCAB can be safely undergone for patients with left ventricular dysfunction if well preoperative and intraoperative management. Surgeons should attempt to personalized management strategy for those patients.