Poor BP Control Ups Risk for Recurrent ICH

Megan Brooks

September 04, 2015

Inadequate control of blood pressure (BP) after intracerebral hemorrhage (ICH) raises the risk for repeat ICH, and the association is stronger with worsening severity of hypertension, new research shows.

The findings, say the researchers, "support the hypothesis that aggressive blood pressure control may reduce this risk substantially."

"The degree of [BP] reduction that best serves survivors of hemorrhagic stroke remains unknown," Jonathan Rosand, MD, chief, Division of Neurocritical Care and Emergency Neurology, Massachusetts General Hospital, Boston, told Medscape Medical News.

"However, our study makes it clear that physicians can do a better a job of keeping the [BP] of their patients within the range currently recommended by national guidelines. We physicians and our patients have work to do," Dr Rosand said.

The study was published in the September 1 issue of JAMA.

Cornerstone of Care

ICH is the most severe and least treatable form of stroke, responsible for nearly half of stroke-related illness and death. Those who survive the event are at high risk for recurrent ICH, death, and worsening disability, the investigators note in their article.

Controlling elevated BP, they point out, is the "cornerstone" of secondary prevention of recurrent nonlobar ICH, but data are lacking on the optimal degree of BP reduction. The role of BP control in lobar ICH remains "poorly defined," they write.

Dr Rosand and colleagues investigated the effect of BP reduction and control on risk for recurrent lobar or nonlobar ICH in 1145 patients with ICH who survived at least 90 days and were followed for a median of 37 months. BP readings were obtained at 3, 6, 9, and 12 months and every 6 months thereafter.

During follow-up, there were 102 recurrent ICH events among 505 survivors of lobar ICH and 44 recurrent ICH events among 640 survivors of nonlobar ICH. Adequate BP control (based on current guidelines) was achieved on at least 1 measurement by 625 patients (54.6% total) and at all available time points by 495 patients (43.2% of total).

Recurrent lobar and nonlobar ICH was more common with inadequate BP control. The event rate for lobar ICH was 84 per 1000 person-years in those with inadequate BP control compared with 49 per 1000 person-years in those with adequate BP control. For nonlobar ICH, event rates were 52 and 27 per 1000 person-years, respectively.

In analyses modeling BP control over time, inadequate BP control was associated with increased risk for recurrence of both lobar and nonlobar ICH.

Table. Risk for Recurrence With Inadequate BP Control

Event Hazard Ratio (95% Confidence Interval) P Value
Lobar ICH 3.53 (1.65 - 7.54) .001
Nonlobar ICH 4.23 (1.02 - 17.52) .048

"The association between elevated BP and ICH recurrence appeared to become stronger with worsening severity of hypertension," the investigators say.

Systolic BP during follow-up was associated with increased risk for both lobar and nonlobar ICH recurrence during follow-up, while diastolic BP was associated with increased risk for nonlobar ICH recurrence only.

Unexpected Findings

"There were several findings that caught us by surprise," Dr Rosand told Medscape Medical News. "The medical community has come to accept the strong relationship" between BP and risk for ICH in the deep brain regions, he explained. "That we would find a similar, albeit less strong, relationship for lobar hemorrhages was unexpected.

"It is further striking that risk of recurrent hemorrhagic stroke seems to go down with progressively lower blood pressures, lower even than the thresholds currently recommended by some national guidelines," Dr Rosand said.

"Finally, it was hard for us to miss that so many of the patients in this study had recorded blood pressures that were in the hypertensive range. Clearly, a message from this paper is that all ICH survivors should consult their physicians to confirm that their blood pressure is well controlled and should remain vigilant that it remains well controlled over their lifetimes," Dr Rosand said.

It's important to note that this was a single-center study in a largely white population. "The degree to which our findings are relevant to other populations requires study in those populations. This is particularly true for African, Hispanic, Asian, and Native Americans, as well as other minorities," Dr Rosand said.

Also of note is that the data do not prove that better BP control will cut the risk for recurrent ICH. "Randomized clinical trials will be necessary to prove that hypothesis. Until such studies are performed, however, physicians and patients who have recovered from an ICH should do everything they can to manage blood pressure according to our current guidelines," he advised.

Brian Silver, MD, director, Comprehensive Stroke Center, Rhode Island Hospital, Providence, and member of the American Heart Association, who wasn't involved in the study, called it "newsworthy."

The study, Dr Silver notes, shows a "steady increase" in the risk for recurrent ICH as BP rises. "The increased risk is seen even in patients whose systolic BP is between 130 and 139 mm Hg (prehypertension). This raises the question as to what clinicians should target for BP after someone suffers an ICH. Should we lower it below 130 as opposed to 140? The [study] seems to suggest benefit."

"On the other hand," Dr Silver said, "lower blood pressures, especially in older patients, may increase the risk of dementia (which may be an issue since some lobar hemorrhages are due to pathologies, ie, amyloid deposition, that are shared with Alzheimer disease). The way to definitely answer the question, as suggested by the authors in their discussion, is through a randomized controlled trial."

The study was supported by the National Institute of Neurological Disorders and Stroke. The authors and Dr Silver have disclosed no relevant financial relationships.

JAMA. 2015;314:904-912. Abstract

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