Optimal blood pressure in asymptomatic aortic stenosis: not too high, not too low

By Will Boggs MD

NEW YORK (Reuters Health) - The optimal blood pressure in patients with asymptomatic aortic valve stenosis seems to be between 130 and 139 mmHg systolic and around 80 mmHg diastolic, researchers from Scandinavia report.

"Physicians are concerned about treating hypertension due to cardiovascular risk and lack of established blood pressure targets for patients with asymptomatic aortic valve stenosis," said Dr. Olav W. Nielsen from Denmark's Copenhagen University Hospital of Bispebjerg.

"Because randomized, controlled trials are scarce, (the new) results will assist the clinicians in designing the patient care and risk-factor management by best available knowledge," he told Reuters Health by email.

Hypertension is a common finding in patients with aortic stenosis, and blood pressure normalization is recommended when evaluating these patients. But there is no consensus recommendation for optimal blood pressure targets in this population, Dr. Nielsen and colleagues note in Circulation, online August 2.

The team used data from the Simvastatin Ezetimibe in Aortic Stenosis (SEAS) study to identify what blood pressure might be optimal with regards to outcomes in patients with asymptomatic aortic stenosis.

During the four years of the study, blood pressure declined by 4 mmHg systolic and 3 mmHg diastolic on average; after four years, more than 90% of blood pressure measurements were missing.

All-cause survival rates were best when systolic blood pressures range from 130 to 139 mmHg systolic and from 60 to 90 mmHg diastolic, the researchers found.

The mortality risk was 70% higher for blood pressures >= 160 mmHg systolic and 60% higher for blood pressures between 120 and 129 mmHg systolic.

Higher diastolic blood pressures were consistently associated with worse outcomes in patients with mild aortic stenosis, whereas lower diastolic blood pressures were associated with increased all-cause mortality and heart failure in patients with moderate aortic stenosis.

Lower systolic blood pressures were linked with harm in patients with mild or moderate aortic stenosis, whereas higher systolic blood pressures were associated with myocardial infarction and cardiovascular death only in patients with mild aortic stenosis.

"This study should advise physicians to implement more careful treatment of blood pressure in patients with asymptomatic aortic valve stenosis," Dr. Nielsen said. "The study documents that the most reasonable blood pressure target will be 130/80 mm Hg for this challenging group of patients with asymptomatic aortic valve stenosis."

"Physicians should probably not lower blood pressure too much in these patients," he added.

"The SEAS investigators have previously enlightened us about the adverse impact of hypertension on the natural history of mild-to-moderate aortic stenosis with normal left ventricular systolic function (Stage B disease) and now provide the clinician with reasonable blood pressure boundaries within which to manage this challenging group of patients," writes Dr. Patrick T. O'Gara from Brigham and Women's Hospital, Harvard Medical School, Boston, in a related editorial.

"A cautious, progressive, individualized, pharmacological approach after lifestyle changes have been implemented is always advised, but no class of medications should be considered strictly out of bounds," he adds.

Cardiologist Dr. Catherine M. Otto from the University of Washington, Seattle, told Reuters Health by email, "In the past, physicians were reluctant to treat hypertension in patients with asymptomatic aortic valve stenosis. With aortic valve obstruction, physicians worried that the heart would be unable to pump more blood across the narrowed valve if systemic resistance was reduced; thus patients might experience an excessive fall in blood pressure resulting in clinical symptoms."

"More recently, we recognize that the heart pumps against the combined resistance of the narrowed valve plus the systemic vasculature and that it is beneficial to treat hypertension in adults with aortic valve narrowing," she explained. "The finding in this study that a blood pressure over 140/90 mmHg was associated with adverse outcomes supports current recommendations to treat hypertension even when aortic stenosis is present. However, further studies are needed because this was not a randomized study of antihypertensive therapy in patients with aortic stenosis."

"When aortic stenosis is present (abnormal valve with an aortic velocity 3 m/s or higher) it is prudent to start therapy at a low dose and titrate upwards gradually to ensure that medications are tolerated and the systolic blood pressure is reduced to 140 mm Hg or less and diastolic blood pressure to 90 mm Hg or less," Dr. Otto advised. "Further studies are needed to determine if a lower blood pressure goal is appropriate or not when aortic stenosis is present."

Dr. Philippe Pibarot from Québec Heart & Lung Institute, Canada, said U-shaped relationships have "been reported in other populations with cardiovascular disease but this is the first time it is demonstrated in patients with aortic stenosis."

"The main limitation of this study is that it does not necessarily represent the general population of aortic stenosis," he told Reuters Health by email. "Indeed, in the SEAS trials patients who had at baseline severe aortic stenosis, coronary artery disease, and/or diabetes were excluded. These patients represent a large proportion of the aortic stenosis population, and they also represent the subset that is at highest risk for poor outcomes."

"So additional studies are needed to determine if these blood pressure targets identified in the present study would also apply in patients with severe aortic stenosis, in symptomatic patients, in patients with concomitant coronary artery disease, etc.," Dr. Pibarot concluded.

Merck & Co., Inc. funded the SEAS study and provided honoraria to several authors of the new report.

SOURCE: https://bit.ly/2aUpmsD and https://bit.ly/2by8XAf

Circulation 2016.