Survival And Echocardiographic Outcomes In On- And Off-pump Coronary Bypass For Patients With Impaired Ventricular Function
Lucian Lozonschi, Jennifer Philip, Takushi Kohmoto, Satoru Osaki, Nilto C. De Oliveira, Ravi Dhingra, Paul C. Tang.
University of Wisconsin-Madison, Madison, WI, USA.
Objective: Management of ischemic cardiomyopathies is evolving in an era of greater ventricular assist devices availability. We examine the durability of improved left ventricular (LV) function and survival following coronary artery bypass grafting (CABG) in a poorly functioning LV.
Methods: Retrospective analysis of 429 patients with LV ejection fraction (EF) <40% undergoing isolated primary CABG from 2000-2016. CABG strategies were on-pump cardioplegic arrest (CA, n=312), 0ff-pump (OPCAB, n=75), and on-pump beating heart (OBH, n=42). A combined OPCAB and OBH group (n=117) was propensity matched for preoperative characteristics to the CA to obtain 114 patients per group.
Results: For the total population, average preoperative LVEF was 31.4+7.1% with an average survival and echocardiographic follow up of 3.7+4.2 and 2.7+3.3 years respectively. OPCAB had more hypertension (P=0.01), cerebrovascular disease (P<0.01), and worse renal function (P=0.02). OBH had the worse LVEF (27.7+7.2%, <0.01). Following CABG, there was an average LVEF increase of 10% (31.4+7.1 vs 41.6+13.6%, P<0.01) with a decrease in LV dimension (P<0.01), and improvement in mitral regurgitation grade (P<0.01). Despite this, RV function worsens over time (P=0.04) with no change in tricuspid regurgitation (P=0.49). No difference in LVEF improvement (ΔLVEF) was seen between the time strata of <1 (9.8+11.2%), 1-5 (11.6+14.5%), and >5 (8.8+14.2%) years (P=0.442). Posterior wall and interventricular septal thickness were unchanged (P>0.05). With propensity matching, there was no difference in postoperative complications (P>0.05), or survival between the CA and combined OPCAB/OBH group (figure, P=0.44). Multivariate Cox regression reveals that preoperative predictors of mortality (P>0.05) include age, weight, creatinine, peripheral vascular disease, right ventricular dysfunction and aortic valve stenosis. There were less circumflex territory grafts (0.68 vs 0.97, P<0.01) in the combined group.
Conclusions: Patients with moderate-severe LV dysfunction experience long term improvement in LVEF following CABG accompanied by a decrease in mitral regurgitation and LV dimension. While there is a preference for OPCAB or OBH for patients with major comorbidities or lower EF, no difference in survival was seen compared with CA.
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