Differential effects of gastric bypass and banding on the cardiovascular risk profile in morbidly obese subjects: The correlation with plasma apolipoprotein A-IV concentration

Abstract

Background: Weight loss (5–10%) improves obesity-associated cardiovascular risk factors. The aim of this work was to study the effect of 2 commonly performed bariatric surgical procedures; laparoscopic Roux-en-Y gastric bypass (RYGBP) and laparoscopic gastric band (BAND), on the cardiovascular risk profile in morbidly obese patients and its correlation with the plasma apolipoprotein (apo) A-IV level.
Patient and method: This study was carried prospectively on 34 patients scheduled for bariatric surgery. They were randomly assigned into two groups; group 1=BAND (18 cases), group 2= gastric bypass RYGBP (16 cases). Both groups were studied preoperatively and twelve months after surgery. Data collected included changes of body mass index (BMI), blood pressure, fasting blood sugar, fasting serum insulin, insulin resistance (HOMA-IR) and lipid profile. In addition, apo A-IV was determined by the Western blot technique.
Results: The results demonstrated a highly significant reduction in body weight as determined by reduction in the BMI in both groups I & II compared to preoperative measurements. Moreover, both groups had a significantly lower systolic blood pressure, fasting blood glucose (FBG), fasting serum insulin and HOMA-IR twelve months after operation. The changes in BMI, systolic blood pressure; FBG and HOMA-IR were significantly more in group II than in group I. The lipid profiles in group I & II before surgery were similar. The HDL-cholesterol was significantly higher  in both groups I & II 12 months after surgery. In addition, apo A-IV levels increased after surgery in both groups.
Conclusion: Both gastric band and gastric bypass are associated with significant improvement of the cardiovascular risk profile, although it is more pronounced after gastric bypass. The improvement correlates well with the increase of apo A-IV in both groups. Thus Apo A-IV may play a positive role in improving the cardiovascular risk profile after bariatric surgery.

Keywords: Obesity; Bariatric surgery; Apo A-IV; Weight loss; Cardiovascular risk factors; HOMA-IR