BP Control More Important in ICH Patients on Antithrombotics

May 15, 2014

NICE, France — Latest results from a combined analysis of the INTERACT (Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial) 1 and 2 studies in patients with intracerebral hemorrhage (ICH) show that early intensive blood pressure lowering results in a reduced absolute growth of hematoma, and this effect was greater in patients who had previously received antithrombotics.

"Early intensive blood pressure lowering appears to provide greater attenuation of hematoma growth among ICH patients with prior use of antithrombotics (especially warfarin)," said Lili Song, MD, Shanghai 85th Hospital of PLA, China. "These results suggest we need to pay greater attention to blood pressure control among patients presenting with antithrombotic-associated ICH."

Dr. Song presented these latest results here at the XXIII European Stroke Conference (ESC).

Hematoma Growth

The INTERACT 2 study, presented last year at this meeting, simultaneously published online in the New England Journal of Medicine and reported by Medscape Medical News at that time, showed that early intensive blood pressure lowering to a target of 140 mmHg systolic in patients with intracerebral hemorrhage (ICH) appeared to be related to less long-term disability.

The earlier smaller INTERACT 1 study showed that early intensive blood pressure lowering reduced hematoma growth in patients with ICH.

Aims of the current analysis were to investigate whether there was greater hematoma growth at 24 hours in patients taking antithrombotic medication and whether early intensive blood pressure lowering has the same or greater effect in the patients taking antithrombotics compared with the overall trial population.

For the analysis, the researchers pooled data on patients who participated in the 24-hour computed tomography (CT) substudies in the INTERACT 1 and 2 trials. This gave a total of 1310 patients with repeat 24-hour CT scans (346 from INTERACT 1 and 964 from INTERACT 2).

Of these, 645 were allocated to the control group and 665 received intensive blood pressure lowering. Among all patients, 235 patients were receiving antithrombotic medication and 1074 were not.

Results showed that prior use of antithrombotic therapy was associated with a greater absolute hematoma volume, a result that remained after adjustment for confounding variables and randomized treatment. And intensive early blood pressure control reduced hematoma growth to a greater extent in the patients taking antithrombotics.

Table. Effect of Early Intensive Blood Pressure–Lowering Treatment on Hematoma Growth by Prior Use of Antithrombotics

Endpoint Hematoma Growth in Intensive Blood Pressure Reduction Group (mL) Hematoma Growth in Control Group (mL) Difference in Hematoma Growth (mL)
  Antithrombotics 3.4 8.1 –4.7
  No antithrombotics 1.1 2.4 –1.3
  Overall 1.9 3.7 –1.8
Hematoma + ICH      
  Antithrombotics 3.2 10.3 –7.1
  No antithrombotics 1.5 3.0 –1.4
  Overall 2.2 4.6 –2.4


Dr. Song said the strengths of the current study included a large sample size and broad range of patients, while limitations included a post hoc analysis and the inability to reliably differentiate effects between aspirin and warfarin.

XXIII European Stroke Conference (ESC). Presented May 9, 2014.


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