Abstract 027: Changes in Renin Angiotensin System Monitored Across Time Following Bariatric Surgery

Abstract

There is scarce information regarding the complete renin-angiotensin-aldosterone system (RAAS) and its changes after bariatric surgery (BS) in patients with morbid obesity (MO). Objective: to analyze changes (Δ) in RAAS components in MO after BS at several follow-up time points. Methods: Fifty-five MO patients (78% women, 40% hypertensives, age 43.4±8.9yr, BMI 42.4±5.3Kg/m 2 ) were evaluated prospectively before and 1,3,6 and 12 months(m) after BS, with assessment of anthropometrics, RAAS components and 24h-systolic BP (SBP). Results: at 12m body weight (-35.1±9.7 Kg) and waist circumference (-27±9.2 cm) decreased (p<0.001). At 1,3 and 6m, there was a reduction in angiotensin-converting enzyme (ACE) and ACE-2 activity, as well as a decrease in plasma renin activity (PRA) and aldosterone from 3m on (Table). The decrease in 24h-SBP at 1m was 6.2 mmHg (3.6 to 8.8), p<0.001. There were correlations (p<0.05) between ΔPRA/Δ24h-SBP at 1m (r=-0.332), 3m (r=-0.330) and 12m (r=-0.322). ΔPRA and Δbody weight correlated only at 1m (r=-0.427). Δaldosterone and Δwaist circumference correlated at 12m (r=-0.372). ΔACE and Δ24h-SBP correlated at 6 and 12m (r=0.451 and r=0.635, respectively). Correlations between Δ24h-SBP and Δbody weight were statistically significant only at 6m (r=0,366; p=0,016). Conclusions: there are sequential changes in several components of the RASS after BS, with an increase in ACE and ACE2 activity as early as 1m after BS that lasts until 6m, and a decrease in PRA and plasma Aldosterone that initiates at 3m and remains 12m after BS. These changes correlate with the decrease of 24h-SBP. RAAS components, but not body weight, appear to correlate with changes in BP after BS.