Improved prediction of poor outcome after thrombolysis using conservative definitions of symptomatic hemorrhage.

BACKGROUND AND PURPOSE

Direct comparison of symptomatic intracerebral hemorrhage (sICH) rates among different thrombolysis studies is complicated by the variability of definitions of sICH. The prediction of outcome still remains unclear.

METHODS

Baseline data and clinical courses of patients treated with thrombolytic therapy were collected in a prospective database. The 3-month outcome was evaluated using the modified Rankin Scale. Results of 24-hour follow-up imaging were reevaluated by at least 2 independent raters. Four common definitions of sICH (National Institute of Neurological Disorders and Stroke [NINDS], European Cooperative Acute Stroke Study [ECASS] 2, Safe Implementation of Thrombolysis in Stroke [SITS], ECASS 3) were applied. Kappa interrater statistics were calculated. Our objective was to find the sICH definition with the highest predictive value for mortality, poor (modified Rankin Scale 5 or 6) and unfavorable (modified Rankin Scale ≥3) clinical outcome after 90 days.

RESULTS

The data of 314 patients were analyzed. The NINDS definition revealed the highest sICH rate (7.7%); the lowest rate was found for the ECASS 3 definition (3.2%) of sICH. The highest interrater agreement was found for the ECASS 2 definition (κ 0.85) and the lowest for the NINDS definition (κ 0.57). Patients with sICH according to the SITS definition had the highest risk for death (OR, 14.4) and poor outcome (OR, 26.6).

CONCLUSIONS

None of the different definitions contains an optimal combination of prediction of mortality and outcome and a high interrater agreement rate. For the clinical evaluation of mortality, we recommend using the SITS definition; for studies needing a high interrater agreement rate, we recommend using the ECASS 2 definition. Due to the lack of 1 single optimal definition, future thrombolytic trials should preferably use different definitions.