Intensive BP Lowering Reduces Hematoma Growth in Intracerebral Hemorrhage

Caroline Cassels

February 26, 2008

February 26, 2008 (New Orleans, Louisiana) — Early intensive treatment for hypertension in patients with acute intracerebral hemorrhage (ICH) is well-tolerated and appears to reduce hematoma growth.

According to late-breaking science results presented here at the American Stroke Association (ASA) International Stroke Conference (ISC) 2008, findings from the pilot phase of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT) showed that patients who received intensive antihypertensive therapy experienced a mean hematoma growth that was 22% lower than their counterparts who did not receive intensive blood pressure–lowering treatment.

Furthermore, frequency of substantial hematoma growth — defined by ongoing bleeding of more than one-third of initial volume — was 36% lower in the intensive group.

"We feel this treatment is feasible, it is safe, and there is a signal, which we believe is robust, that indicates we can arrest bleeding in the brain," principal investigator Craig Anderson, MD, PhD, from the George Institute for International Health, in Sydney, Australia, told reporters attending an ISC press conference.

High blood pressure is a cause of ICH, and it is also very common at the acute stage of illness. However, said Dr. Anderson, all of the guidelines for blood pressure control in acute stroke, including ICH, are based on nonrandomized, observational data. Therefore, he said doctors are uncertain of how to manage it.

Most Serious Form Of Stroke

However, he added, what is known is that every incremental increase in blood pressure, particularly systolic blood pressure, correlates with poorer outcomes, including death or dependence.

"We believe that high blood pressure causes extra bleeding and expansion of blood in the brain, so theoretically if we can bring the blood pressure down we might be able to arrest the bleeding in the brain or get it under control," he said.

ICH, he said, affects approximately 1 million people annually worldwide — with individuals in the United States accounting for 100,000 of these cases.

"It is the most serious form of stroke. In whites it probably accounts for 10% of stroke, but among African Americans, Hispanics, and Asians it accounts for about 20% to 30%, and in some places in China it accounts for half of all stroke," said Dr. Anderson.

"Presumably, this is related to the growing prevalence of hypertension and possibly other unknown factors in these populations," he added.

The study included 404 patients from 44 hospitals in Australia, China, and Korea recruited from November 2005 to April 2007. All subjects had an acute ICH confirmed by computerized tomography and elevated systolic blood pressure of 150 to 220 mm Hg.

Patients were randomly assigned to receive either intensive antihypertensive treatment based on a titrated protocol of routinely available intravenous agents to a target systolic blood pressure of 140 mm Hg or a less intensive treatment targeted to a systolic blood pressure of 180 mm Hg based on American Heart Association guidelines.

Less Blood in the Brain

Each patient began treatment in a monitored environment within 6 hours of suffering an acute ICH. After the first hour, systolic blood pressure was an average of 13.3 mm Hg lower in the intensive-therapy group than the guidelines-adjusted group. This equated to approximately 2.5 ml or half a teaspoon of less blood in the brain.

At 90-day follow-up, said Dr. Anderson, there was no evidence that early intensive blood pressure lowering increased the risk for adverse events.

A larger, phase 3 study of INTERACT that will include 2500 patients and examine the impact of intensive blood pressure lowering on clinical outcomes on ICH patients will be launched later this year, said Dr. Anderson.

Larry Goldstein, MD, from Duke University, in Durham, North Carolina, and a spokesperson for the ASA, told Medscape Neurology & Neurosurgery that the INTERACT study offers the potential for improved patient outcomes.

"Right now, we have no real proven therapies for acute intracerebral hemorrhage, and there has been controversy because of the lack of data as to the best way to manage blood pressure in these patients. The [study's] finding that intensive blood pressure lowering is associated with lower hematoma growth is encouraging and will hopefully lead to better outcomes," he said

The study was funded by the National Health and Medical Research Council of Australia.

American Stroke Association International Stroke Conference 2008: Abstract LB 3. Presented February 22, 2008.

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