White Matter Lesions Double the Risk of Post-Thrombolytic Intracerebral Hemorrhage

Background and purpose: Cerebral white matter lesions (WMLs), a surrogate for small-vessel disease, are common in patients with stroke and may be related to an increased intracranial bleeding risk after intravenous thrombolysis in acute ischemic stroke. We aimed to investigate the risk of symptomatic intracerebral hemorrhage (sICH) in the presence of WMLs in a large cohort of ischemic stroke patients treated with intravenous thrombolysis.

Methods: We included 2485 consecutive patients treated with intravenous thrombolysis at the Helsinki University Central Hospital. WMLs were scored according to 4 previously published computed tomography visual rating scales from all baseline head scans. A sICH was classified according to the European Cooperative Acute Stroke Study II criteria. The associations of sICH with nominal, ordinal, and continuous variables were analyzed in a univariate binary regression model and adjusted in multivariate binary regression models.

Results: In univariate and multivariate regression analyses, all 4 tested visual WML rating scales (as continuous variables or dichotomized at different cutoff points) were associated with increased risk of sICH. In binary analyses, WML doubled the bleeding risk: the odds ratios of all 4 visual rating scales ranged from 2.22 (95% confidence interval, 1.49-3.30) to 2.70 (1.87-3.90) in univariable and from 2.00 (1.26-3.16) to 2.62 (1.71-4.02) in multivariable analyses. The multivariable-adjusted odds ratio for the association of high load of WMLs with remote parenchymal hemorrhage was 4.11 (2.38-7.10).

Conclusions: WMLs visible on computed tomography are associated with a more than doubled risk of sICH in patients treated with intravenous thrombolysis for acute ischemic stroke.