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02-02-2012 | Surgery | Article

Asymptomatic hemorrhagic transformation doubles odds for worse stroke outcome


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MedWire News: Asymptomatic hemorrhagic transformation is not an innocuous finding, say researchers who report that it doubles patients risk for worse outcomes after stroke.

The impact of asymptomatic hemorrhagic transformation is debatable, with previous studies, including a pooled analysis of 1197 patients, failing to find an effect.

The current study, by Hee-Joon Bae (Seoul National University Bundang Hospital, Seongnam, Korea) and colleagues, included 1412 stroke patients from a prospective stroke registry who were hospitalized within 7 days of symptom onset.

Similar to previous studies, the team analyzed the patients' outcomes on the modified Rankin Scale (mRS) at 3 months. But rather than assessing patients' chances of a good functional outcome, defined as mRS 0-2, for example, they studied the impact of hemorrhagic transformation on the shift in mRS scores across the entire range (0-6).

Bae et al reasoned that this shift analysis would be more sensitive to the effect of asymptomatic hemorrhagic transformation than would a dichotomized analysis. And they stress that "each discrete mRS score indicates a clinically relevant level of functional status."

The rate of asymptomatic hemorrhagic transformation in the team's study was 7.1%, which is relatively low compared with some previous studies and clinical trials. The researchers attribute this to factors including fairly mild stroke severity in their cohort and to exclusion of patients with signs of hemorrhage on the baseline imaging.

But they acknowledge that their findings may not fully apply to patient populations with high rates of asymptomatic ICH.

Asymptomatic hemorrhagic transformation was most likely to occur among patients with cardioembolic stroke (46%), and among those who received thrombolytic therapy (39%) or heparin (30%). Patients with asymptomatic hemorrhagic transformation had more severe stroke than those without, with median National Institutes of Health Stroke Scale scores of 9.5 versus 4.0.

On multivariate analysis, patients with asymptomatic hemorrhagic transformation were 1.90 times more likely to have a poorer functional outcome (a higher mRS score) than those without. The association was independent of factors including age, gender, previous stroke, stroke subtype and severity, and treatment with thrombolysis and heparin.

However, the researchers note in Neurology: "All the [hemorrhagic transformation] in this study developed during hospitalization and might be potentially preventable or reducible in its severity by interventions."

By Eleanor McDermid

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