Associations Between Body Mass Index And Clinical Outcomes In Acute Myocardial Infarction Supported With Extracorporeal Membrane Oxygenation

Background: Previous studies have reported a "body mass index (BMI) paradox" with acute myocardial infarction (AMI), whereby overweight patients are associated with lower mortality. The aim of this study was to evaluate the impact of BMI on survival of patients with AMI supported with extracorporeal membrane oxygenation (ECMO).Methods: Between May 2009 and July 2018, 60 patients with AMI who underwent ECMO were enrolled from a single center. Receiver operating characteristic curve analysis was used to determine a cutoff for BMI. Patients were divided into two groups: normal weight (18.5 BMI <= 23 kg/m(2), n = 27) and overweight (BMI >= 23 kg/m(2), n = 33). The composite outcome was all-cause mortality at 30 days.Results: The overweight group was significantly younger than the normal weight group, and there was a statistically significant difference between the two groups in electrocardiography before ECMO. Ventricular tachycardia or fibrillation occurred in 11 (33.3%) overweight patients, and asystole or pulseless electrical activity occurred in 10 (37%) normal weight patients. More of the normal weight group had successful percutaneous coronary interventions than the overweight group. The overweight group was significantly associated with lower mortality [hazard ratio (HR): 0.491; 95% confidence interval (CI) = 0.267-0.903] at 30 days, which persisted after multivariate adjustments (HR: 0.442; 95% CI = 0.210-0.928). To determine predictive factors for mortality, multivariate logistic analysis revealed that overweight [odds ratio (OR) 0.102; 95% CI (0.018-0.564); p = 0.009] and ECMO under cardiopulmonary resuscitation [OR 19.009; 95% CI (2.139-168.956); p = 0.008] were significantly associated with all-cause mortality at 30 days.Conclusions: Overweight was associated with lower mortality in AMI patients supported with ECMO.