Gastric Bypass to Treat Obese Patients With Steady Hypertension - GATEWAY
Contribution To Literature:
The GATEWAY trial showed that gastric bypass surgery along with medical therapy results in significantly better BP control compared with medical therapy alone among middle-aged obese patients with HTN.
The goal of the trial was to assess the safety and efficacy of bariatric surgery in improving blood pressure (BP) control among obese patients with hypertension (HTN).
Obese patients on ≥2 antihypertensive agents were randomized in a 1:1 fashion to either gastric bypass surgery + medical therapy (n = 49) or medical therapy alone (n = 47). The trial was conducted in an open-label fashion.
- Total number screened: 1,489
- Total number of enrollees: 100
- Duration of follow-up: 1 year
- Mean patient age: 44 years
- Percentage female: 70%
- Baseline BMI: 37 kg/m2
- Percentage with diabetes mellitus: 8%
- Mean 10-year Framingham risk score (FRS): 4.8%
- Mean number of antihypertensives at baseline: 3
- Age 18-65 years
- HTN treated with ≥2 antihypertensive drugs at maximum doses or >2 drugs at moderate doses
- Body mass index (BMI) 30-39.9 kg/m2
- Systolic BP ≥180 mm Hg or diastolic BP ≥120 mm Hg
- Cardiovascular disease (myocardial infarction or stroke within 6 months, angina, coronary revascularization, heart failure)
- Severe psychiatric disorders
- Chronic kidney disease
- Peripheral arterial disease
- Atrophic gastritis
- Type 1 diabetes mellitus, latent autoimmune diabetes of adults, or type 2 diabetes mellitus with glycated hemoglobin >7.0%
- Alcoholism or use of illicit drugs
- Current smoking
- Previous abdominal surgery
- Severe hepatic diseases
- Pregnancy or women of childbearing age not using effective contraceptive methods
- Cancer in the past 5 years
- Use of immunosuppressive drugs, chemotherapy, or radiotherapy
The primary outcome, 30% reduction in number of antihypertensive medications while maintaining controlled BP, for gastric bypass vs. medical therapy, 83.7% vs. 12.8%, relative risk 6.6, 95% confidence interval 3.1-14.0, p < 0.001.
Secondary outcomes for gastric bypass vs. medical therapy:
- Remission of HTN: 51% vs. 0%, p < 0.05
- BMI: 26.8 vs. 36.3 kg/m2, p < 0.001
- Waist circumference: 86.9 vs. 109.8 cm, p < 0.001
- Fasting plasma glucose: 84 vs. 98.4 mg/dl, p < 0.001
- Low-density lipoprotein cholesterol: 86.9 vs. 116.5 mg/dl, p < 0.001
- 10-year FRS: 4.5 vs. 6.8%, p = 0.04
- Mortality: 0 vs. 0
- Rehospitalization: 12% vs. 0%, p = 0.03
- Anemia: 20% vs. 10%, p = 0.23
The results of this trial indicate that gastric bypass surgery results in significantly better BP control compared with medical therapy alone among middle-aged obese patients with HTN. More than one-half of the patients in the gastric bypass arm were no longer hypertensive at 1 year of follow-up. There were also salutary effects on metabolic parameters, including glucose and cholesterol control; the trial was not powered to assess clinical endpoints. Nutritional deficiencies including anemia and low vitamin B12 levels were more common among patients undergoing gastric bypass surgery.
This is an interesting trial. Of nearly 1,500 patients that were screened, only 100 patients were enrolled, suggesting that generalizability may be an issue. Longer-term follow-up of these patients is also important since the effects of bariatric surgery can wane over time. Similar benefits were noted for glycemic control among obese patients in the STAMPEDE trial.
Schiavon CA, Bersch-Ferreira AC, Santucci EV, et al. Effects of Bariatric Surgery in Obese Patients With Hypertension: The GATEWAY Randomized Trial (Gastric Bypass to Treat Obese Patients With Steady Hypertension). Circulation 2017;Nov 13:[Epub ahead of print].
Presented by Dr. Carlos A. Schiavon at the American Heart Association Annual Scientific Sessions (AHA 2017), Anaheim, CA, November 13, 2017.
Keywords: AHA17, AHA Annual Scientific Sessions, Anemia, Antihypertensive Agents, Bariatric Surgery, Blood Glucose, Blood Pressure, Body Mass Index, Cholesterol, Dyslipidemias, Fasting, Gastric Bypass, Glucose, Hypertension, Metabolic Syndrome X, Obesity, Primary Prevention, Risk, Vitamin B 12 Deficiency, Waist Circumference, Primary Prevention
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