Gastric Bypass Surgery Is Followed by Lowered Blood Pressure and Increased Diuresis - Long Term Results from the Swedish Obese Subjects (SOS) Study

Abstract

ObjectiveTo compare two bariatric surgical principles with regard to effects on blood pressure and salt intake.BackgroundIn most patients bariatric surgery induces a sustained weight loss and a reduced cardiovascular risk profile but the long-term effect on blood pressure is uncertain.MethodsCohort study with data from the prospective, controlled Swedish Obese Subjects (SOS) study involving 480 primary health care centres and 25 surgical departments in Sweden. Obese patients treated with non-surgical methods (Controls, n = 1636 and n = 1132 at 2 y and 10 y follow up, respectively) were compared to patients treated with gastric bypass (GBP, n = 245 and n = 277, respectively) or purely restrictive procedures (vertical banded gastroplasty or gastric banding; VBG/B, n = 1534 and n = 1064, respectively).ResultsAt long-term follow-up (median 10 y) GBP was associated with lowered systolic (mean: −5.1 mm Hg) and diastolic pressure (−5.6 mmHg) differing significantly from both VBG/B (−1.5 and −2.1 mmHg, respectively; p<0.001) and Controls (+1.2 and −3.8 mmHg, respectively; p<0.01). Diurnal urinary output was +100 ml (P<0.05) and +170 ml (P<0.001) higher in GBP subjects than in weight-loss matched VBG/B subjects at the 2 y and 10 y follow-ups, respectively. Urinary output was linearly associated with blood pressure only after GBP and these patients consumed approximately 1 g salt per day more at the follow-ups than did VBG/B (P<0.01).ConclusionsThe purely restrictive techniques VBG/B exerted a transient blood pressure lowering effect, whereas gastric bypass was associated with a sustained blood pressure reduction and an increased diuresis. The daily salt consumption was higher after gastric bypass than after restrictive bariatric surgery.

Practical Recommendations of the Obesity Management Task Force of the European Association for the Study of Obesity for the Post-Bariatric Surgery Medical Management

“…Metformin may be continued until normal glucose levels are achieved and maintained [6], but metformin doses may need to be reduced due to increased absorption [82] (see ‘Type 2 Diabetes' above ) . Caution should be applied when administering diuretics post-operatively, as the combined diuretic effect of the drugs and the operation may cause dehydration [83]. NSAIDs, salicylates, corticosteroids and other drugs that may cause gastric damage should be avoided [84,85].…”

The role of bariatric surgery in the treatment of diabetes

“…The mechanisms for improved blood pressure are multifactorial and may be associated with weight loss, reduced systemic inflammation, increased urinary sodium loss and restoration of metabolic homeostasis. Operations such as the RYGB may have additional urinary sodium excretion effects, which may result in longer-term superior blood pressure improvements compared with gastric banding [Hallersund et al 2012]. It is common for drugs such as angiotensin-converting enzyme inhibitors (ACEis) to be stopped after surgery.…”

An Evaluation of Knowledge regarding Surgical Treatment of Obesity among Final Year Medical Students and Recent Graduate Physicians from King Abdulaziz University

“…Significant reduction of hypertension and the normalization of lipid disorders, which are, together with diabetes, criteria for the diagnosis of metabolic syndrome was observed after bariatric treatment. Consequently, results in a reduction of the risk of cardiovascular disease [13][14][15][16][17][18]. Thus , it gives bariatric surgeons a leading role in the treatment of morbidly obese patients.…”