Letter by power regarding article, "Severe renal impairment is associated with symptomatic intracerebral hemorrhage after thrombolysis for ischemic stroke".

BACKGROUND AND PURPOSE Patients with renal impairment (RI) have an increased risk of both thrombotic and hemorrhagic events. We aimed to clarify whether RI increases the risk of intracerebral hemorrhage (ICH) after intravenous thrombolysis with recombinant tissue plasminogen activator. METHODS Patients who received intravenous thrombolysis with recombinant tissue plasminogen activator within 4.5 hours of symptom onset were retrospectively analyzed. Creatinine levels on admission served to calculate glomerular filtration rate (GFR) to estimate RI according to International Classification of Diseases criteria. Effect of RI on symptomatic ICH (sICH) was assessed using dichotomized (GFR <90 and <30 mL/min) and continuous GFR (centered data to test for linear and centered and squared data to test for curvilinear association). RESULTS Of the 740 patients included, 83% had any RI (GFR <90 mL/min) and 5% had severe RI (GFR <30 mL/mL); 4.6% experienced sICH. Univariate comparisons revealed higher prevalence of sICH in patients with severe RI (P<0.01) but not with any RI. GFR as a continuous variable (centered and squared) was also associated with sICH (P=0.02), but GFR on its own was not. Severe RI and GFR (centered and squared) remained independently associated with sICH in multiple regression analyses. CONCLUSIONS Severe RI (GFR <30 mL/min) is associated with sICH after intravenous thrombolysis with recombinant tissue plasminogen activator. The association is curvilinear. Severe RI must be taken into account when balancing the risk-benefit ratio of intravenous thrombolysis with recombinant tissue plasminogen activator.