Background: Symptomatic intracerebral hemorrhage (sICH) and major bleeding can be fatal complications of intravenous thrombolysis (IVT) for acute ischemic stroke. We investigated the impact of early fibrinogen depletion after IVT on major bleeding events.
Methods: This multicenter observational prospective cohort study enrolled 1678 consecutive patients receiving IVT for acute ischemic stroke at 6 Italian centers, undergoing fibrinogen concentration assessment at baseline, 2 hours and 6 hours after IVT. Fibrinogen depletion was defined as a reduction below 200 mg/dL after 2 hours from IVT, or as a reduction below 50% of baseline fibrinogen levels after 2 hours from IVT. Main outcomes were (1) sICH (National Institute of Neurological Disorders and Stroke criteria) and (2) major bleeding defined as fatal bleeding, decrease in the hemoglobin level>2 g/dL/>1 unit transfusion, or bleeding at critical site. Additional outcomes were (1) any ICH, (2) any bleeding, (3) fatal ICH, and (4) sICH according to ECASSII definition. Good functional recovery was defined as modified Rankin Scale score 0 to 2 at 3 months.
Results: Overall, 1678 patients were included (mean age 72 years, 46% female). sICH (n=116) and major bleeding (n=297) were associated with lower rate of good functional recovery (P<0.001). Despite similar fibrinogen levels at admission, fibrinogen depletion after 2 hours from IVT was more common in people with sICH, major bleeding and all additional bleeding outcomes. In the backward stepwise multivariable logistic regression model, fibrinogen depletion remained a significant predictor of sICH (OR, 1.55 [95% CI, 1.04-2.32]) and major bleeding (OR, 1.36 [95% CI, 1.03-1.8]). Thirty-one percent of sICH could be attributable to fibrinogen depletion. The association between fibrinogen depletion and worse clinical outcome at 3 months after stroke (P=0.012) was attributable to the higher risk of major bleeding/sICH.
Conclusions: Fibrinogen depletion significantly increases the risk of sICH and major bleeding after IVT for acute ischemic stroke. Fibrinogen depletion represents an independent risk factor for bleeding, and routine assessment could be considered to stratify the risk of ICH. Trials on early fibrinogen repletion are needed to investigate mitigation of bleeding risk.
Keywords: fibrinogen; hemorrhage; plasminogen; stroke; thrombolytic therapy.