http://www.theheart.org/article/1314003.do?utm_campaign=newsletter&utm_medium=email&utm_source=20111121_EN_Heartwire
A new study points again to evidence of the fabled J-curve of cardiovascular-event risk associated with blood-pressure levels [1]. Among patients with recent noncardioembolic stroke, systolic blood pressures (SBP) >140 mm Hg and <120 mg Hg were both associated with increased risk of recurrent stroke.
The study, a post hoc analysis of data from the Prevention Regimen for Effectively Avoiding Second Strokes (PROFESS) trial, is published in the November 16, 2011 issue of the Journal of American Medical Association. The issue, with a cardiovascular-disease theme, was released early to coincide with the American Heart Association 2011 Scientific Sessions.
"Our results indicate that there may indeed be thresholds of benefit or harm with regard to short-term or longer-term [systolic blood-pressure] SBP levels after a recent noncardioembolic ischemic stroke and imply that clinicians regularly caring for stroke patients in the outpatient setting may need to be vigilant about how low a given patient's BP is within the normal range to promote favorable outcomes," the researchers, with lead author Dr Bruce Ovbiagele (University of California, San Diego) conclude.
They caution, however, that these data should be considered hypothesis generating and the notion that aggressively and consistently lowering BP levels within the normal range after an ischemic stroke is not beneficial "remains unproven and will require the conduct of dedicated clinical trials comparing intensive with usual BP reduction in the stable follow-up period after a stroke."
In the meantime, the results support aiming for consistent systolic BP of <140 mm Hg and diastolic BP of <90 mm Hg in patients with a recent stroke, they conclude.
In an interview, Ovbiagele said that, based on this new information, he wouldn't actually attempt to increase blood pressure in those with very low SBPs but rather would try to optimize their overall vascular risk profile.
But for those patients in the high-normal range below 140 mm Hg, he said, "based on this study I wouldn't try to keep them below 120 mm Hg as the guidelines call for; again, I would keep them where they are and optimize overall vascular risk reduction."
PROFESS Trial
Current secondary-stroke-prevention guidelines suggest maintaining a normal blood pressure, defined as SBP of <120 mm Hg and diastolic BP of <80 mm Hg, in a patient with a prior stroke, the authors note. However, there are limited data looking at BP levels within the normal range for risk reduction after a stroke.
Last year, analyses from two large blood-pressure trials showed evidence of a J-shaped curve, with no benefit of more aggressive SBP targets of <120 mm Hg in high-risk patients with diabetes in the ACCORD study, and perhaps even harm in the INVEST trial from SBP targets <130 mg Hg and diastolic BP <85 mm Hg in patients with diabetes and heart disease.
In the wake of these findings, they write, "there is mounting interest in exploring the existence and nature of the J-shaped link of BP with outcome in various patient groups at high risk for vascular events. For stroke, the vascular disease entity most highly correlated with BP, it is generally perceived that a J-shaped association between BP and outcome may not exist."
In this analysis, they used data from the PROFESS trial, a 2x2 factorial trial comparing four regimens: a combination of aspirin and extended-release dipyridamole compared with clopidogrel and telmisartan compared with placebo. All patients also received antihypertensive medications at the discretion of the investigator. In all, 20 330 patients from 695 centers in 35 countries were randomized within about 30 days of having a noncardioembolic ischemic stroke.
The main results of the trial didn't show any significant difference between these treatments, the authors note, so all patients were combined for this study.
Patients were categorized by their mean SBP level over follow-up as very low normal (<120 mm Hg), low normal (120 to <130 mm Hg), high normal (130 to <140 mm Hg), high (140 to <150 mm Hg) and very high (>150 mm Hg).
The primary outcome was first recurrence of stroke of any type, and the secondary outcome was a composite of stroke, MI, or death from vascular disease.
They found that, using high-normal SBP as a reference, rates of both primary and secondary outcomes were increased in the high and very high SBP ranges, but also in the very low-normal range.
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