The relationship between baseline blood pressure and computed tomography findings in acute stroke: data from the tinzaparin in acute ischaemic stroke trial (TAIST).

Background and Purpose: High blood pressure (BP) is present in approximately 80% of patients with acute ischemic stroke and is independently associated with poor outcome. There are few data examining the relationship between admission BP and acute CT findings.
Methods: TAIST was a randomized controlled trial assessing 10 days of treatment with tinzaparin versus aspirin in 1489 patients with acute ischemic stroke (<48 hr) with admission BP of </=220/120 mmHg. CT brain scans were performed before randomization and after 10 days. The relationships between baseline BP and adjudicated CT findings were assessed. Odds ratios per 10 mmHg change in BP were calculated.
Results: Higher systolic BP (SBP) was associated with abnormal CT scans because of independent associations with chronic changes of leukoariosis (OR, 1.12; 95% CI, 1.05-1.17) and old infarction (OR, 1.12; 95% CI, 1.06-1.17) at baseline, and signs of visible infarction at day 10 (OR, 1.06; 95% CI, 1.00-1.13). A lower SBP was associated with signs of acute infarction (OR, 0.94; 95% CI, 0.89-0.99). Hemorrhagic transformation, dense middle cerebral artery sign, mass effect, and cerebral edema at day 10 were not independently associated with baseline BP.
Conclusions: Although high baseline BP is independently associated with a poor outcome after stroke, this was not shown to be through an association with increased hemorrhagic transformation, cerebral edema, or mass effect; trial design may be suboptimal to detect this. Higher SBP is associated with visible infarction on day 10 scans. The influence of changing BP in acute stroke on CT findings is still to be ascertained.