Ambulatory blood pressure and neuroendocrine control after diet-assisted gastric restrictive surgery

Background Long-term weight control after conventional diet is disappointin g but may be improved when diet is assisted by gastric restrictive surgery (GRS). Objective To determine the effects of GRS on ambulatory blood pressure (ABP ) and neuroendocrine BP control in 28 morbidly obese subjects, Methods A BP and heart rate were recorded every 10 min for 25 h before and 4 months after GRS, Effects of marked reductions in body weight on the reni n-angiotensin-aldosterone system, on plasma insulin and on sympathetic acti vity were also determined. Results Body mass index decreased from 43 +/- 1 to 34 +/- 1 kg/m(2) and sys tolic (S) BP decreased by 7 +/- 2 mmHg during daytime (P = 0.01) and by 8 /- 3 mmHg during the night (P = 0.02). Pulse pressure, a marker of reduced arterial compliance, decreased by 5 +/- 1 mmHg throughout the 24 h period ( P < 0.001), Diastolic BP remained unchanged. Heart rate decreased more duri ng the night (-13 +/- 2 bpm, P < 0.0001) than during daytime (-5 +/- 2 bpm, P = 0.03). Reductions in SEP were largest in subjects with highest initial BP values (r = -0.63, P < 0.001) but were unrelated to weight loss. GRS de creased fasting glycaemia, plasma insulin, plasma C peptide and 24 h urine sodium (n = 20) and noradrenaline (n = 19) excretion (P < 0.01). Conclusions Diet-assisted GRS favourably affects neuroendocrine BP control in obese patients. Reductions in sodium intake, insulin levels and sympathe tic tone combined with possible improvements in arterial compliance induce persistent 24 h reductions in SEP and pulse BP, Reductions in BP are larges t in subjects with highest initial BP values and are unrelated to the amoun t of weight loss, thereby emphasizing the importance of even moderate reduc tions in weight on BP control. J Hypertens 2000, 18:301-306 (C) Lippincott Williams & Wilkins.