Background and purpose: Hemorrhagic transformation is frequently seen on CT scans obtained in the subacute phase of ischemic stroke. Its prognostic value is controversial.
Methods: We analyzed 554 patients with acute ischemic stroke enrolled in the Multicenter Acute Stroke Trial-Italy (MAST-I) study in whom a second CT scan was performed on day 5. Presence of 1) intraparenchymal hemorrhages (hematoma or hemorrhagic infarction), 2) extraparenchymal bleeding (intraventricular or subarachnoid) and 3) cerebral edema (shift of midline structure, sulcal effacement or ventricular compression) alone or in association were evaluated. Death or disability at 6 months were considered as "unfavorable outcome."
Results: Patients who developed intraparenchymal hemorrhages, extraparenchymal bleeding, or cerebral edema had unfavorable outcome (83%, 100%, and 80%, respectively), but multivariate analysis demonstrated that only extraparenchymal bleeding (collinearity) and cerebral edema (OR=6.8; 95% CI, 4.5 to 10.4) were significant independent prognostic findings. Unfavorable outcome correlated with size of intraparenchymal hemorrhage (chi2 for trend=30.5, P<0.0001). Nevertheless, when a large hematoma was present the negative effect was mostly due to concomitant extraparenchymal bleeding (chi2=51.6, P<0.0001), and when hemorrhagic infarction was detected the negative effect was mostly explained by the association with cerebral edema (chi2=36.6, P<0.0001).
Conclusions: Extraparenchymal bleeding and cerebral edema are the main prognostic CT scan findings in the subacute phase of ischemic stroke. Stroke patients with a high risk for developing these 2 types of brain damage should be identified. Measures to prevent and adequately treat their development should be implemented.