Defining clinically relevant cerebral hemorrhage after thrombolytic therapy for stroke: analysis of the National Institute of Neurological Disorders and Stroke tissue-type plasminogen activator trials.

BACKGROUND AND PURPOSE: Several definitions have been proposed to distinguish clinically relevant from incidental cerebral hemorrhagic transformation after thrombolytic therapy for acute ischemic stroke. We investigated which definition best identifies cerebral hemorrhages that alter long-term functional outcome in the National Institute of Neurological Disorders and Stroke (NINDS) tissue-type plasminogen activator (tPA) trials.

METHODS: We analyzed 4 candidate hemorrhage definitions for which the NINDS tPA trials public data set had relevant data. For each, we identified tPA-treated patients having that hemorrhage type and compared their actual functional outcomes at 90 days with their predicted outcomes had they not received tPA and not had the hemorrhage. Projected outcomes without tPA were based on a 17-variable prognostic model derived from the NINDS tPA trials placebo group.

RESULTS: Among the 312 patients treated with intravenous tPA, 33 (10.6%) experienced any radiological intracerebral hemorrhage <36 hours of treatment, 16 (5.1%) a radiological parenchymal hematoma, 20 (6.4%) a NINDS tPA trials-defined symptomatic intracerebral hemorrhage, 12 (3.8%) an European-Australian Cooperative Acute Stroke Study 2 (ECASS2)-defined symptomatic intracerebral hemorrhage, and 6 (1.9%) a modified version of the Safe Implementation of Thrombolysis in Stroke Monitoring Study (mSITS-MOST)-defined symptomatic intracerebral hemorrhage. The ECASS2 and mSITS-MOST definitions identified the largest hemorrhage-related change in 90-day modified Rankin Scale scores (2.26-0.32=1.94, P=0.0001; 2.81-0.63=2.18, P=0.0002, respectively). These definitions also distinguished the largest hemorrhage-related change in 90-day mortality (64.7%-7.6%=57.1%; P=0.0004 for ECASS2; 68.4%-19.5%=48.9%; P=0.0152 for mSITS-MOST).

CONCLUSIONS: The ECASS2 and mSITS-MOST symptomatic intracerebral hemorrhage definitions, which combine radiological features and occurrence of substantial early neurological deterioration, best identify tPA hemorrhages that alter final patient outcome.