Impact of Bariatric Surgery on Mortality of Mitral Valve Surgery: A National Analysis

Objective: Obesity is a common comorbidity of cardiac surgery patients. The goal of this study is to determine if a lower weight achieved through bariatric surgery has any association with mitral valve (MV) replacement or repair surgery mortality.Methods: This study used a retrospective analysis of the National Inpatient Sample dataset from 2012 to 2020. Adult patients who underwent MV surgery with normal weight following bariatric surgery (n= 1,125) and patients with obesity (n= 48,555) were compared. The primary outcome was in-hospital mortality.Results: This study included 49,680 patients. The median age was 64 (55 to 71) years, and the majority were female (55%). Bariatric surgery was found to significantly decrease the odds of mortality, even after adjusting for important covariates, indicating a reduction of mortality risk by 54% (adjusted odds ratio = 0.46, p= 0.024). Other significant protective factors include isolated and elective surgery. Significant risk factors were older age, female sex, and diabetes mellitus. Patients who were obese demonstrated longer lengths of stay (LOS), greater transfers to other facilities, and higher hospital costs.Conclusions: In patients receiving MV surgery, bariatric surgery demonstrated significant survival benefits during hospitalization, in addition to reducing LOS and cost. Our data support prior evidence of bariatric surgery improving cardiovascular outcomes. Therefore, bariatric surgery may be a meaningful method of weight loss to improve surgical patient outcomes in patients with obesity. However, longer-term data are needed.