Interpretation and Implementation of Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT II)

Abstract

The second Intensive Blood Pressure Reduction in
Acute Cerebral Hemorrhage Trial (INTERACT II)1
randomized 2,839 patients with intracerebral hemorrhage (ICH) within 6 h of symptom onset to intensive
systolic blood pressure (SBP) reduction, with a target of
<140 mm Hg within 1 h, or guideline-recommended
SBP reduction, with a target of <180 mm Hg using a
variety of antihypertensive medications. The primary
outcome was death or major disability defined by a
score of 3–6 on the modified Rankin scale (mRS) at 3
months post-randomization. The proportion of subjects
with death or major disability was 719 of 1,382 (52%) in
the group randomized to receive intensive BP reduction
compared with 785 of 1,412 (55.6%) in the group
randomized to receive guideline-recommended treatment (odds ratio [OR] with intensive treatment, 0.87;
95% confidence interval [CI], 0.75–1.01; p = 0.06). In
the secondary analysis, mRS grades were analyzed as an
ordinal scale, which detected significantly lower mRS
scores in subjects randomized to intensive SBP reduction (common OR, 0.87; 95% CI, 0.77–1.00; p = 0.04).
After the publication, the Antihypertensive Treatment of
Acute Cerebral Hemorrhage (ATACH) II investigators’
prepared a report for its Data and Safety Monitoring
Board to determine implications of INTERACT II on
current practice and on ATACH II trial design and conduct (Table 1).
Patient selection
In general, INTERACT II used broad criteria for defining the target population which resulted in relatively fast
patient enrollment but increased the variability in patient
population and response to treatment. Certain criteria
that raised specific concerns are also discussed below