Differential Effects of Bariatric Surgery Versus Exercise on Excessive Visceral Fat Deposits

Abstract

The aim of the present study was to compare differential impacts of bariatric surgery and exercise-induced weight loss on excessive abdominal and cardiac fat deposition.Excessive fat accumulation around the heart may play an important role in the pathogenesis of cardiovascular disease. Recent evidences have suggested that bariatric surgery results in relatively less decrease in epicardial fat compared with abdominal visceral fat and paracardial fat.Sixty-four consecutive overweight or obese subjects were enrolled in the study. Clinical characteristics and metabolic profiles were recorded. The volumes of abdominal visceral adipose tissue (AVAT), abdominal subcutaneous adipose tissue (ASAT), epicardial (EAT), and paracardial adipose tissue (PAT) were measured by computed tomography in the bariatric surgery group (N = 25) and the exercise group (N = 39) at baseline and 3 months after intervention. Subjects in both the surgery and exercise groups showed significant reduction in body mass index (15.97%, 7.47%), AVAT (40.52%, 15.24%), ASAT (31.40, 17.34%), PAT (34.40%, 12.05%), and PAT + EAT (22.31%, 17.72%) (all P < 0.001) after intervention compared with baseline. In both the groups, the decrease in EAT was small compared with the other compartments (P < 0.01 in both groups). Compared with the exercise group, the surgery group had greater loss in abdominal and cardiac visceral adipose tissue (AVAT, ASAT, PAT, EAT+PAT) (P < 0.001), but lesser loss in EAT (P = 0.037).Compared with the exercise group, bariatric surgery results in significantly greater percentage loss of excessive fat deposits except for EAT. EAT, but not PAT, was relatively preserved despite weight reduction in both the groups. The physiological impact of persistent EAT deserves further investigation.

FIGURE 1

The flowchart scheme of the study.

FIGURE 2

Quantification of different fat deposits by CT. Total pericardial volume = total EAT volume + total PAT volume. (A–C) Measurement of total EAT volume was performed on axial images by manual tracing (blue boundary) of the parietal pericardium from the left main pulmonary artery level to the left ventricular apex. Measurement of total pericardial fat volume by manual tracing (red boundary) of the area of the pericardial fat from the left main pulmonary artery level to the left ventricular apex. Total PAT volume (yellow boundary) = total pericardial fat volume (PAT + EAT) − total EAT volume. (D–F) Measurement of total AVAT volume was performed on axial images by manual tracing (blue boundary) of the parietal peritoneum from L2 to L5 levels. Measurement of total abdominal fat volume by manual tracing (red boundary) of the area of the abdominal fat from L2 to L5 levels. Total ASAT volume (yellow boundary) = total abdominal fat volume (AVAT + ASAT) − total AVAT volume. ASAT = abdominal subcutaneous adipose tissue, AVAT = abdominal visceral adipose tissue, EAT = epicardial adipose tissue, PAT = paracardial adipose tissue.

FIGURE 3

(A) Comparison of relative change (%) at different excessive fat deposits in the bariatric surgery group. (B) Comparison of relative change (%) at different excessive fat deposits in the exercise group. ASAT = abdominal subcutaneous adipose tissue, AVAT = abdominal visceral adipose tissue, BMI = Body Mass Index, EAT = epicardial adipose tissue, PAT = paracardial adipose tissue, WC = waist circumference.