Bariatric Surgery Can Lead to HTN 'Remission' in Obese: GATEWAY

November 13, 2017

ANAHEIM, CA — Bariatric surgery can allow obese people taking a lot of antihypertensive meds to cut way back on them, so their blood pressure is maintained in the normal range with only one agent or even without drugs, suggests a small randomized study[1].

The trial's patients, who had a body-mass index (BMI) of 30 to <40 kg/m2 (mean about 37 kg/m2 across both groups) and were on at least two blood-pressure (BP)–lowering agents at baseline, underwent laparoscopic Roux-en-Y gastric-bypass surgery plus meds or medical therapy alone.

Within a year, those who had the surgery were more than six times as likely to have cut back on their number of BP meds by about a third. Half of the surgical patients didn't need antihypertensive meds to maintain their BP under 140/90 mm Hg. But all of the standard-care patients needed antihypertensives to keep BP that low, and half of them needed at least three.

Moreover, in a post hoc analysis of the study, called Gastric Bypass to Treat Obese Patients With Steady Hypertension (GATEWAY), about 20% of patients who underwent bariatric surgery achieved the more ambitious systolic BP target of <120 mm Hg espoused by the SPRINT trial.

Simply put, bariatric surgery "made it easy to treat hypertension in these patients," Dr Carlos Aurelio Schiavon (Research Institute, Heart Hospital, São Paulo, Brazil) told theheart.org | Medscape Cardiology.

He reported the GATEWAY study here today at the American Heart Association (AHA) 2017 Scientific Sessions at about the same time it was published in Circulation, with him as lead author.

For patients with obesity who have to treat their hypertension with more than two agents, a group that often has difficulty adhering to their meds, "I think bariatric surgery can be a very effective and useful treatment, to make them more adherent to treatment and have more controlled blood pressure," Schiavon said.

Right now, bariatric surgery can't be recommended for controlling hypertension in patients with BMI 30 to <35 kg/m2, at least outside of clinical trials, he said; the surgery for metabolic improvement is reserved for people with higher BMIs.

"But in the future, for patients with obesity, on four or five drugs for difficult-to-treat hypertension, maybe the surgery can be indicated for those specifically," he said when interviewed.

These days, "the patients we're referring quickly to bariatric surgery are people with intractable heart-failure symptoms, intractable diabetes, and truly refractory hypertension," Dr Donald Lloyd-Jones (Northwestern University Feinberg School of Medicine, Chicago, IL) said to theheart.org | Medscape Cardiology.

"But this is a very compelling trial that indicates that at lower levels of BMI and [with] not really horribly refractory [high] blood pressure at all, we see pretty dramatic benefits," he said.

GATEWAY, according to Lloyd-Jones, who is not connected with the study, is "small but compelling, and I think it does help us to understand just where this may start to fit in our armamentarium in the future."

The trial's patients, 70% of whom were women, which Schiavon said makes sense for a bariatric surgery trial, averaged 44 years old. Any with a BP of ≥180/120 mm Hg, chronic kidney disease, or diabetes were excluded.

Antihypertensive meds included ACE inhibitors or angiotensin receptor blockers (ARBs) with a calcium-channel blocker as first-line choices, preferably followed, as needed, by a thiazide diuretic and then by spironolactone or clonidine, the published report notes.

Controlled BP with a reduction of at least 30% in the total number of antihypertensive agents, the primary end point, was seen in 41 gastric-bypass patients but only six in the medical and lifestyle-management group, 83.7% and 12.8%, respectively, for a rate ratio (RR) of 6.6 (95% CI 3.1–14.0; P<0.001).

Remarkably, Schiavon noted, 51% of the surgical patients experienced remission of their hypertension, that is office-measured BP maintained below 140/90 mm Hg at 1 year without BP meds, compared with none in the control group.

In the post hoc analysis based on the more ambitious SPRINT targets, 11 patients in the gastric-bypass group, or 22.4%, achieved a systolic BP of <120 mm Hg at 1 year without any antihypertensive meds, compared with none in the control group.

As for the primary end point based on the SPRINT systolic BP threshold, 32.7% of surgical patients achieved that lower BP level while reducing their antihypertensive meds by at least 30%, compared with only 8.5% for controls, for an RR of 3.8 (95% CI 1.4–10.6; P=0.005).

Weight, BMI, and waist-circumference improvements at 1 year were better among the 49 patients in the gastric-bypass group compared with the 47 on medical and lifestyle therapy only (P<0.001 for all measures). BMI at follow-up was 26.8 and 36.3 kg/m2, respectively.

While those differences might be expected, "and one could imagine that's the main reason for the remission or the reduction of medications in the gastric-bypass group," Schiavon said, "most patients in the gastric-bypass group achieved the primary end point in the first month of the postop period." That seems to mean, he said, that "something more is happening beyond weight loss."

That something is likely to be related, at least in part, to the metabolic changes in the surgery group compared with the control group, which included significant improvements in fasting plasma glucose, HbA1c, LDL cholesterol, triglycerides, and high-sensitivity C-reactive protein (P<0.001 surgery vs control, for all biomarkers).

At a media briefing on the trial, Dr Paul Poirier (Quebec Heart and Lung Institute, Quebec City), the scheduled discussant for Schiavon's scheduled presentation of the trial, noted that gastric-bypass surgery and its attendant effects on adiposity are known to improve insulin resistance, renal function, sympathetic tone, and inflammatory status.

More globally, the surgery group had superior improvement in 10-year Framingham risk score.

The study was supported by Ethicon. Schiavon discloses receiving research grants from, participating in a speaker's bureau for, and receiving honoraria from Johnson & Johnson Brazil. Disclosures for the coauthors are listed in the paper. Lloyd-Jones had no disclosures. Poirier discloses consulting for Abbott Vascular, Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, Eli Lilly, Janssen, Merck, Novo Nordisk, Pfizer, Roche, Sanofi, Servier, and Valeant.

Follow Steve Stiles on Twitter: @SteveStiles2. For more from theheart.org | Medscape Cardiology, follow us on Twitter and Facebook.

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