Functional Outcome of Hemorrhagic Transformation after Thrombolysis for Ischemic Stroke: A Prospective Study

Hemorrhagic transformation (HT) is usually taken into account when symptomatic, but the role of asymptomatic HT is not well known. The aim of our study was to evaluate the link between HT after thrombolysis for ischemic stroke and functional outcome at 3 months, with particular emphasis on asymptomatic HT.

Our study was performed prospectively between June 2012 and June 2013 in the Stroke Unit of the University Hospital Center of Tours (France). All patients treated with intravenous thrombolysis were consecutively included. HT was classified on susceptibility-weighted imaging (SWI) with 3-tesla MRI at 7 ± 3 days after treatment. We evaluated functional outcome at 3 months using the modified Rankin Scale (mRS). Dependency was defined as an mRS score of ≥ 3.

After 1 year, 128 patients had received thrombolytic therapy for ischemic stroke, of whom 90 patients underwent both 3-tesla MRI and SWI at day 7. Fifty-two had HT, including 8 symptomatic cases. At 3 months, 68% of those patients were dependent compared to 31% of patients without HT [OR 4.6 (1.9-11.4), p = 0.001]. In asymptomatic HT, the rate was 62% [OR 3.5 (1.4-8.9), p = 0.007], but did not reach significance after adjustment for stroke severity.

Our study found no statistically significant effect of HT on outcome after adjustment for initial stroke severity. However, the innocuousness of HT is not certain, and only few studies have already highlighted the increased risk of dependency. Using 3-tesla MRI with SWI allows us to increase the detection rate of small hemorrhage.

HT after thrombolysis is very frequent on SWI, but the initial stroke severity is an important predictor to assess the role of HT for patient outcome.