Abstract 14842: Half of the Implantable Cardioverter Defibrillator-Eligible Patients That Undergo Coronary Artery Bypass Graft Surgery Improve Their Ejection Fraction to Above 35% Post-operatively

Abstract

Background: In patients with preoperative ejection fraction (EF) ≤35%, a 90-day waiting period after coronary artery bypass grafting (CABG) is recommended to assess the impact of revascularization on left ventricular (LV) EF, prior to considering implantable cardioverter-defibrillator (ICD) therapy for primary prevention of sudden cardiac death. However, there is very little data to show whether EF improves to >35% after CABG, rendering these patients ICD-ineligible postoperatively. We sought to determine the incidence and predictors of EF improvement to >35% in ICD-eligible patients undergoing CABG. Methods: Of the 2,838 patients who underwent isolated CABG between 2001 and 2014 at the Minneapolis Veterans Affairs Medical Center, 375 had echocardiographic assessment of LV EF before (within 6 months) and after (3-24 months) CABG. Of these 375 patients, 74 (20%) had an LV EF ≤35% prior to CABG and were examined in this analysis. Logistic regression was used to examine the variables associated with perioperative improvement in LV EF. Results: Mean age of the 74 patients was 65±9 years. Mean preoperative EF was 28±6%, and improved to 36±12% postoperatively (p< 0.001). In 38 (51%) patients, EF improved to >35% after CABG (mean EF in this subgroup increased from 29±5% to 46±8% postoperatively, p< 0.001). Improvement in EF to >35% was 5 times more likely in patients with a preoperative EF of 26-35% than those with preoperative EF ≤25% (odds ratio 4.95, 95% confidence interval 1.73 to 14.1; p=0.003). Other baseline clinical characteristics were similar between patients with vs. without an improvement in EF to >35%. Conclusion: More than 50% of the ICD-eligible patients who underwent CABG with a preoperative EF ≤35% improved their EF to >35% after CABG and became disqualified for primary prevention ICD therapy. Preoperative EF was a strong determinant of EF improvement postoperatively. These results provide evidence for the current practice guideline recommendation of reassessing EF 90 days after CABG in ICD-eligible patients. They also suggest that it is less likely for patients with a preoperative EF ≤25% to become ineligible for primary-prevention ICD after CABG.