Complications following thrombolysis
POST-TREATMENT MORBIDITY AND MORTALITY
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ICH is a major risk associated with thrombolytic therapy. The frequency of ICH has been associated with a delay in the initiation of intravenous thrombolysis of 4 to 6 hours or more after stroke onset.However, the relationship between ICH and poor outcome, independent of the severity of the initial ischemic event, is not clearly defined. In ECASS II, the higher frequency of severe ICH in the alteplase group (8.1%) than in the placebo group (0.8%) did not result in an overall increase in morbidity and mortality in the alteplase group, despite 40% favorable outcomes in the treated group and 37% favorable outcomes in the placebo group.27In the NINDS study, the incidence of symptomatic ICH was 6.4% (20 of 312 patients) in the alteplase group and 0.6% in the placebo group.25 The mortality rate of patients in the alteplase group who had symptomatic ICH was 45%. In PROACT I, each of 5 patients found to have hypodensity exceeding 33% of the affected hemisphere on the initial CT scan (ECASS criteria) developed ICH within 24 hours.33
In PROACT II, symptomatic ICH occurred only in patients with a baseline NIHSS score of 11 or higher. In this study, symptomatic ICH occurred in 12 of 110 (11%) patients (target population) treated with r-pro UK and in 2 of 64 (3%) receiving heparin alone. Mortality after symptomatic ICH was 83% (10 of the 12 patients). Blood glucose level exceeding 200 mg/dl at stroke onset was associated with the risk of symptomatic ICH in PROACT II.66 Severity of stroke, longer time to recanalization, and high glucose levels have been reported as independent predictors of ICH in other series of IA thrombolysis.67-70
In the PROACT I and II trials, the mortality rates at 90 days were 27% and 25% in the r-pro UK groups and 43% and 27% in the placebo groups, respectively (Table 3).33,34 In PROACT I, one fatal ICH occurred in each treatment group. Two patients died of cardiac causes and four patients died of stroke in the r-pro UK group. In the placebo group, three deaths were related to stroke and two were cardiac in origin. In the study conducted by Qureshi et al., the mortality rate was 56% (9 of 16 patients).41 All four patients who developed ICH post-thrombolysis died. A higher median NIHSS score of 20 (range 10-26) in that study in comparison to 17 (range 5-27) in PROACT II may account for the observed differences in the mortality rate. Both PROACT I and II excluded patients with a baseline NIHSS score exceeding 30. Improved patient selection and an understanding of the mechanisms involved in the development of ICH may reduce the morbidity and mortality associated with IA thrombolysis.
Reprinted with permission from Mohr JP, Choi DW, Grotta JC, Weir B, Wolf PA (eds): STROKE: PATHOPHYSIOLOGY, DIAGNOSIS, AND MANAGEMENT (4th edition), pp. 1475-1520 (chapter 78), Copyright Elsevier 2004. Permission has been granted to reproduce this material in online electronic format for non-exclusive world English rights.