Background and purpose: Asymptomatic hemorrhagic transformation of infarction (AHTI) is common, but its risk factors and relationship with functional outcome are poorly defined.
Methods: The analyses used data from the Tinzapararin in Acute Ischaemic Stroke Trial, a randomized controlled trial assessing tinzaparin (low molecular weight heparin) versus aspirin in 1484 patients with acute ischemic stroke. CT head scans (baseline, day 10) were adjudicated for the presence of hemorrhagic transformation. Stroke subtype was classified according to modified Trial of Org 10172 in Acute Stroke Treatment (small vessel, large vessel, cardioembolic) and the Oxfordshire Community Stroke Project (total anterior, partial anterior, lacunar, and posterior circulatory syndromes). Modified Rankin scale and Barthel Index were measured at 3 and 6 months. Analyses were adjusted for age, sex, severity, blood pressure, infarct volume, and treatment. Symptomatic hemorrhage was excluded.
Results: At day 10, AHTI did not differ between aspirin (300 mg; 32.8%) and medium-dose (100 IU/kg; 36.0%) and high-dose (175 IU/kg; 31.4%) tinzaparin groups (P = 0.44). Relative to lacunar stroke, AHTI on follow-up CT was significantly increased in total anterior circulation syndrome (odds ratio, 11.5; 95% CI, 7.1 to 18.7) and partial anterior circulation syndrome (odds ratio, 7.2; 95% CI, 4.5 to 11.4) stroke. Similarly, relative to small vessel disease, AHTI was increased in large vessel (odds ratio, 15.1; 95% CI, 9.4 to 24.3) and cardioembolic (odds ratio, 14.1; 95% CI, 8.5 to 23.5) stroke. After adjustment for infarct volume, the presence of AHTI was not associated with outcome at 3 or 6 months as measured by the modified Rankin Scale and Barthel Index.
Conclusions: AHTI is increased in ischemic stroke with cortical syndromes and of large vessel or cardioembolic etiology. Heparin does not increase AHTI. AHTI is not associated with functional outcome.