BODY-COMPOSITION AND SOURCE OF WEIGHT-LOSS AFTER BARIATRIC SURGERY

Background: Little is known about the composition and source of weight loss after bariatric surgery for morbid obesity. Purpose: This study was undertaken to determine changes in weight, body mass index (BMI), lean body weight (LBW), fat weight (FW) and left ventricular cardiac m ass (LVM) following vertical banded gastroplasty (VBG). Methods: After VBG for morbid obesity, 26 women and four men (mean age = 39.1 years) were weighed and had body composition analysis undertaken at interval s. Thirteen patients underwent echocardiography preoperatively and 1 y ear postoperatively to determine change in LVM and LVM index. Results: Over 12 months there was significant weight loss for all weight param eters examined (p < 0.05). Fat weight loss was most significant; total weight loss and reduction of BMI were significant but less so than fa t loss (Wilcoxon's signed ranks test). LBW loss had the smallest contr ibution to weight loss (p < 0.0001). There was a significant loss of L VM and posterior cardiac wall thickness (p < 0.05). Conclusions: VBG c an lead to loss of lean body weight and left ventricular mass, and mor e dramatically, fat weight, body weight, and BMI. Cardiac mass and lea n body mass are preferentially conserved relative to body fat with wei ght loss after VBG.