Effects of bariatric surgery on sympathetic activity and cardiac risk in non-diabetic severely obese patients — ASN Events

Effects of bariatric surgery on sympathetic activity and cardiac risk in non-diabetic severely obese patients (#124)

Elisabeth Lambert 1 , Toni Rice 1 , Nina Eikelis 1 , Nora Straznicky 1 , Gavin Lambert 1 , Chris Hensman 2 , Markus Schlaich 1 , John Dixon 1
  1. Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
  2. Lap-Surgery Australia, Boronia, Victoria, Australia

Background: Obesity is associated with elevated cardiovascular mortality which may be attributed, in part, to sympathetic nervous activation and an associated poor metabolic profile. Laparoscopic Adjustable Gastric Band (LAGB) surgery provides substantial weight loss and leads to long-term health-related beneficial effects. However, the effect of a more modest weight loss, such as the initial goal of 10% weight loss set by the clinical guidelines may already confer beneficial effects through improvement of sympathetic function.
Objectives: We sought to examine the effects of LAGB on cardiovascular profile and sympathetic nervous system (SNS) activity and baroreflex function following the recommended initial 10% weight loss.
Subjects & Methods: Twenty three severely obese non diabetic individuals (17 females, 6 males, BMI = 42.2 kg/m2) underwent cardiovascular risk profile [metabolic profile, ambulatory blood pressure (BP) and renal function] and SNS function assessments (microneurography) prior to LAGB surgery and when they achieved 10% weight loss.
Results: Participants achieved 10% weight loss at an average of 7.3±1.4 months varying from 1.3 to 23.3 months. This was associated with significant improvement in systolic and diastolic BP (-12 mmHg and -5 mmHg respectively), a decrease in muscle SNA (33±3 to 22±3 bursts per minute), improvement in cardiac (16 ±3 to 31±4 ms.mmHg-1) and sympathetic (-2.23±0.39 to -4.30±0.96 bursts/100 heartbeats.mmHg-1) baroreflex function, total cholesterol (5.33±0.13 to 4.97±0.16 mmol/l), fasting insulin (29.3±2.4 to 19.6±1.1 mmol/l) and creatinine clearance (172±11 to 142±8 ml/min). None of the cardiovascular risk improvement related to the rate of weight loss.
Conclusion: The clinical guideline of 10% weight loss goal induced by LAGB is associated with substantial improvement of cardiovascular risk profile in severely obese individuals. These changes were accompanied by improvement in the SNS function.