Letter by Siegler and Martin-Schild Regarding Article, “Comparison of Risk-Scoring Systems in Predicting Symptomatic Intracerebral Hemorrhage After Intravenous Thrombolysis”
To the Editor:
Treatment with intravenous tissue-type plasminogen activator (tPA), while highly effective when administered in the appropriate setting, was associated with a 3% risk of hemorrhage producing deterioration in randomized trials.1 Efforts to minimize symptomatic intracerebral hemorrhage (sICH) focused on identifying risk factors and led to the development of composite scores that integrate multiple demographic and clinical factors to estimate odds of sICH.
A multicenter investigation conducted by Sung et al,2 recently published in Stroke, has shed light on the generalizability of several of these scoring methods to predict sICH after treatment with intravenous tPA in Taiwanese centers. In this study, which included a relatively large sample size of intravenous tPA-treated patients (n=548), various risk prediction models for sICH were assessed and applied to the various definitions of sICH that currently exist in the literature.
Although each of the scoring systems addressed in this study showed a correlation between higher scores and greater odds of sICH, even the highest scores which predict the most severe prognosis were associated with rates of sICH <20%. One concern we have about this study and each of the referenced studies from which these scores are derived involves the potential bias in treating physicians at these centers for deciding against intravenous tPA in patients with sICH risk factors. If such bias were present, patients included in these studies would be inherently less likely to have sICH, impacting the ability of these scoring models to predict sICH. In addition, the prevalence of the variables included in various sICH risk models is not uniform across all populations. This impacts the generalizability of the predictive capacity of the models because certain risk factors may be more prevalent in other patient populations.3
With the growing number of scoring models which predict sICH after thrombolysis, we are concerned with how these models will be used. Although thrombolytic treatment rates are improving, they remain astoundingly low. If sICH scoring models are used in the assessment of individual patients, clinical personnel may be concerned about higher risk of sICH and scare otherwise eligible patients with ischemic stroke to decide against treatment during discussion of risk–benefit. In the past 5 years at our center, our intravenous tPA treatment rate has increased steadily, approaching 45%. Despite our aggressive treatment strategy (including wake-up strokes and extended window strokes), only 3.8% of our patients treated with intravenous tPA experienced sICH according to the Safe Implementation of Thrombolysis in Stroke-Monitoring Study definition.4 We would certainly not use an sICH risk model to decide against treatment for patients who can be treated within the first 4.5 hours, for whom the models were generated. Furthermore, our own data suggest that commonly used models have only modest ability to predict sICH in our population.
Because of the differing predictive abilities of each of the available sICH scoring systems, we encourage centers to determine which model performs the best in their population and to use the models for academic and educational purposes to monitor whether actual sICH rate exceeds the anticipated rate. However, we do not recommend using these risk models as a justification to withhold treatment. Enough contraindications exist already.
James E. Siegler, MD
Sheryl Martin-Schild, MD, PhD
Stroke Program, Department of Neurology
Tulane University School of Medicine
New Orleans, LA
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- © 2013 American Heart Association, Inc.
- Sung SF,
- Chen SC,
- Lin HJ,
- Chen YW,
- Tseng MC,
- Chen CH