Right ventricular performance in severe obesity. Effect of weight loss

The effects of severe obesity on right ventricular function in the absence of associated cardiopulmonary disease are not well known. Right myocardial performance index (R-MPI) is an echocardiographic index to non-invasively assess the right ventricular function. The aim of our study was to assess R-MPI in individuals with severe but uncomplicated obesity before and after a significant weight loss induced by bariatric surgery.

Fifteen obese females (OB) without cardiovascular and pulmonary diseases were examined. In all subjects, R-MPI was calculated by Doppler echocardiography as the sum of isovolumetric contraction time and isovolumetric relaxation time divided by ejection time. Furthermore, pulmonary function test (PFT) and 6-min walking test (6mWT) were performed. Ten healthy subjects with normal weight (HS) were also evaluated as controls. R-MPI, PFT and 6mWT were also re-evaluated one year later in 12 obese subjects treated with gastric banding after a consistent weight loss (> 20%).

A prolongation of R-MPI was found in OB before bariatric surgery in comparison to the HS (0.47 +/- 0.04 and 0.29 +/- 0.05, respectively; P < 0.001). R-MPI significantly improved in OB 12 months after surgery (0.32 +/- 0.03) and was no longer different from HS. R-MPI positively correlated to body mass index (BMI). A significant association was found between the reduction of BMI after bariatric surgery and the distance walked during the 6mWT.

These results show a right ventricular dysfunction in severe uncomplicated obesity, associated with an impaired functional capacity which recovers after consistent weight loss.