Venous thromboembolism prevention with low molecular weight heparin may reduce hemorrhagic transformation in acute ischemic stroke

Background: Subcutaneous heparin at a prophylactic dose (SHPD) is a rather common treatment in ischemic stroke, but whether it confers an increased risk of hemorrhagic transformation of cerebral infarct (HT) and whether its reduction or discontinuation favors HT regression are presently poorly understood. Methods: Two samples of ischemic stroke patients with a cerebral lesion diameter ≥ 3 cm on brain CT scan, admitted over 7 years to our stroke unit, were retrospectively examined: (1) patients treated or not treated with SHPD (enoxaparin 4000 U/day), with subsequent assessment of possible HT appearance (N = 267, mean age 75.9 ± 12.8 years) and (2) patients treated with SHPD, with HT and subsequent reduction/discontinuation or maintenance of the initial dose, and subsequent assessment of HT evolution (N = 116, mean age 75.7 ± 11.1 years). HT severity was quantified according to the ECASS study (HT score). Results: In the first sample, after adjustment for age, sex, stroke severity, cerebral lesion diameter, and other possible confounders, SHPD was inversely associated with HT appearance (hazard ratio 0.62, 95% CI 0.39–0.98, P = 0.04). In the second sample, after adjustment for age, sex, stroke severity, cerebral lesion diameter, and initial HT severity, SHPD reduction/discontinuation had an inverse effect on both HT score improvement (odds ratio 0.42, 95% CI 0.18–0.99, P = 0.049) and HT improvement according to neuroradiological reports (odds ratio 0.34, 95% CI 0.14–0.82, P = 0.015). Conclusions: This retrospective study suggests that SHPD may play a protective role in HT appearance and evolution, which requires verification by a randomized clinical trial.