Background: Heart failure (HF) with improved ejection fraction (HFiEF) is defined as a new subset in addition to the subsets of HF with reduced EF (≤40%; HFrEF) and HF with preserved EF (>40%). The characteristics and outcomes of patients with ischemic HFiEF after coronary revascularization are unknown.
Methods and Results: We identified 1,816 patients with coronary artery diseases and reduced EF (≤40%) in a large hospital in China, who underwent either coronary artery bypass graft surgery (n=1,126) or percutaneous coronary intervention with drug eluting stent (n=687) from January 2005 to December 2014. All patients had EF reassessment during follow-up. The improvement of EF peaked at 3 months and persisted for more than one year after revascularization. Thus, 589 patients who had EF reassessment between 3 to 12 months after revascularization were included in the definitions of HFiEF and HFrEF patient cohort and subsequent survival analysis. 367 (62.3%) patients had EF >40% which constituted HFiEF cohort while 222 (37.7%) patients with EF≤40% constituted HFrEF cohort. Using stepwise logistic regression, we identified preoperative EF (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.02-1.11; P=0.006), left ventricular end-systolic diameter (OR, 0.93; 95% CI, 0.91-0.95; P=0.000) and history of myocardial infarction (OR, 0.61; 95% CI, 0.42-0.88; P=0.008) were associated with being in HFiEF group. Using Cox proportional hazard models, HFiEF patients had lower risk of all-cause mortality (hazard ratios [HR], 0.39; 95% CI, 0.23-0.68; P=0.001), sudden cardiac death (HR, 0.32; 95% CI, 0.14-0.75; P=0.009) and death due to HF (HR, 0.13; 95% CI, 0.03-0.52; P=0.004) compared to HFrEF patients. Nonproportional outcome of composite end points (i.e., combination of all-cause mortality, HF hospitalization and repeat revascularization) between HFiEF and HFrEF groups was detected by using the Schoenfeld residuals. By using flexible parametric model, patients with HFiEF had similar risk of composite end points in the first 5 years (HR, 0.84; 95% CI, 0.53-1.31; P=0.433), but significantly lower risk during years 6 to 11(HR, 0.12; 95% CI, 0.03-0.56; P=0.007). In the HFiEF group, the risk of death were age (HR, 1.07; 95% CI, 1.02-1.12; P=0.008), current smoking (HR, 5.62; 95% CI, 1.93-18.18; P=0.002) and history of myocardial infarction (HR, 2.89; 95% CI, 1.05-7.93; P=0.039). By contrast, in the HFrEF group, the risk factors were moderate or severe mitral regurgitation (HR, 1.81; 95% CI, 1.06-3.11; P=0.031) and estimated glomerular filtration rate (HR, 0.97; 95% CI, 0.95-0.99; P=0.014).
Conclusions: Patients with ischemic HFiEF have distinct clinical characteristics and favorable outcomes. Our data support HFiEF as a distinct HF category in ischemic HF patients after revascularization therapy.