Rapid BP Lowering in Acute Intracerebral Hemorrhage: Risky?

Henry R. Black, MD


August 22, 2013

INTERACT2 Findings

The primary outcome in INTERACT2 was death or a poor outcome, as judged by the inability to function, going to an extended care facility, not being mobile, being depressed and anxious -- many things that happen to patients who have had strokes. They found no significant difference in these outcomes (although it was very close statistically) even though they recruited a large number of subjects and randomly assigned them adequately. In looking at the size of the hematomas that occurred with the intracerebral hemorrhages, there wasn't any growth or shrinkage when blood pressure was lowered faster rather than slower. They found a 7% reduction in [the size of the hematoma] favoring the intensive group.

There were improvements in many of the surrogate measures -- anxiety, depression, mobility, and quality-of-life issues -- but the primary outcome wasn't any different. There were approximately 1400 subjects in each group, and the investigators found no reduction in the primary endpoint. They achieved a blood pressure difference of 164 mm Hg [in the intensive group] vs 150 mm Hg [in the group with standard treatment]. They had planned on about a 13% reduction and they achieved 14%, so that was good, but they also saw that quality of life, depression, and anxiety improved [in the intensive group].

A curious finding, however, was that a larger number (5%) of the subjects in the intensive group withdrew from therapy compared with the standard group (3%). The investigators didn't explain this finding, and I am not sure why this would occur in a blinded study. The subjects didn't know what they were getting. This was a so-called PROBE (Prospective Randomized Open Blinded End-point) study, so the investigators knew, but the people who analyzed the data didn't. They have shown in INTERACT2 that it is safe to lower blood pressure quickly. This has some benefit, but it is much more important to prevent that sort of event rather than wait until it happens and correct it later.

The main drug used to lower blood pressure is urapidil, an alpha-adrenergic antagonist not available in the United States but available in much of the rest of the world. We are doing a similar study now with nicardipine, a calcium-entry blocker, but it isn't planned to be finished until about 2014 or 2015. Hopefully we can compare these 2 agents down the road.

Thank you very much.


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