Abstract MP32: Variation in NT-proBNP Levels After Bariatric Surgery and Its Association With Body Fat Percentage

Abstract

Introduction: Natriuretic peptides are regulators of the cardiovascular system that are also related to adiposity and insulin resistance. NT-proBNP levels are inversely associated with adiposity and increase with weight loss, which may have hemodynamic implications in obesity. However, it is unclear if the changes in NT-proBNP with weight loss are independent of changes in insulin resistance and related metabolic risk factors. Hypothesis: NT-proBNP increases with surgical weight loss are partially independent of changes in other metabolic risk factors. Methods: We investigated 71 patients from the BARI-Heart Study, a prospective cohort with anthropometrics, metabolic risk factors and biomarkers before and after bariatric surgery. We compared data between pre- and post-surgical visits (1-2 weeks and 6 months, respectively) using t-tests, and performed regression analysis examining the association of changes adiposity measures with NT-proBNP before and after adjusting for metabolic risk factors. Results: After bariatric surgery, major reductions in weight, body-mass index (BMI) and body fat percentage (BFP) (mean change) were observed (Table 1), whereas NT-proBNP levels increased (mean change +61 pg/mL, SD 104). There were significant reductions post-surgery in HOMA-IR (from 9.9 to 2.6; p <0.0001), as well as in triglycerides, total cholesterol, glucose, and blood pressure (all p<0.05). A negative correlation between changes in ln-NT-proBNP and BFP was found ( r -0.27; p=0.03). In regression analysis, the inverse association remained statistically significant after adjustment for changes in the other metabolic risk factors (Table 2). Conclusions: Reductions in adiposity are linked to increases in NT-proBNP independent of changes in metabolic risk factors. The mechanisms and cardiovascular implications of this direct link between weight loss and NT-proBNP deserve further investigation.