Mid-term outcomes of coronary artery bypass grafting in patients with mild left ventricular systolic dysfunction: a multicentre retrospective cohort study

OBJECTIVES: Left ventricular systolic dysfunction (LVSD) is common and associated with adverse events in patients receiving coronary artery bypass grafting (CABG). However, the prognosis of mild LVSD has not been clearly described. We aimed to evaluate the mid-term outcomes of patients with mild LVSD following CABG. METHODS: This multicentre cohort study using propensity score matching took place from December 2012 to October 2019 in Jiangsu Province, China, with a mean and maximum follow-up of 3.2 and 7.2 years, respectively. Patients were classified to normal left ventricular systolic function (left ventricular ejection fraction >= 53%) and mild LVSD (left ventricular ejection fraction >40%/<53%). The primary outcomes were death from all causes and death from cardiovascular causes. The secondary outcomes were heart failure, myocardial infarction, repeat revascularization and a composite of all mentioned outcomes, including death from all causes (major adverse events). RESULTS: A total of 581 pairs were formed after matching. In-hospital death (1.5% vs 2.1%, P = 0.51) did not differ between 2 cohorts. Throughout 7 years, mild LVSD was associated with higher rates of death from all causes [hazard ratio (HR) 0.59, 95% confidence interval (CI) 0.39-0.89; P = 0.012], death from cardiovascular causes (HR 0.55, 95% CI 0.36-0.90; P = 0.017), heart failure (HR 0.60, 95% CI 0.37-0.93; P = 0.023) and major adverse events (HR 0.66, 95% CI 0.49-0.91; P = 0.009). There was no difference in the rates of myocardial infarction and repeat revascularization. CONCLUSIONS: Mild LVSD was associated with a worse mid-term prognosis in patients following CABG.