Two Tales: Hemorrhagic Transformation but Not Parenchymal Hemorrhage After Thrombolysis Is Related to Severity and Duration of Ischemia

<jats:p> <jats:bold> <jats:italic>Background and Purpose—</jats:italic> </jats:bold> Intracerebral hemorrhage represents the most feared complication of treatment with intravenous tissue plasminogen activator. We studied whether perfusion-weighted imaging and diffusion-weighted imaging has the potential to identify patients at risk of severe intracerebral hemorrhage after treatment with intravenous tissue plasminogen activator. </jats:p> <jats:p> <jats:bold> <jats:italic>Methods—</jats:italic> </jats:bold> We analyzed data of prospectively studied MRI selected acute ischemic stroke patients treated with intravenous tissue plasminogen activator within 6 hours. All patients were examined by perfusion- and diffusion-weighted imaging ≤6 hours. Perfusion- and diffusion-weighted imaging lesion volumes were calculated. Hemorrhagic transformation was assessed on follow-up CT or MRI and diagnosed as hemorrhagic transformation, parenchymal hemorrhage, or symptomatic intracerebral hemorrhage according to ECASS II criteria. </jats:p> <jats:p> <jats:bold> <jats:italic>Results—</jats:italic> </jats:bold> Of 152 patients, hemorrhagic transformation was seen in 60 (39.5%), parenchymal hemorrhage in 15 (9.9%), and symptomatic intracerebral hemorrhage in 4 (2.6%). Multiple logistic regression analysis identified onset to treatment time after 3 to 6 hours ( <jats:italic>P</jats:italic> <0.001), a larger perfusion-weighted imaging lesion volume ( <jats:italic>P</jats:italic> =0.002), and, as a tendency, a higher score on the National Institutes of Health Stroke Scale on admission ( <jats:italic>P</jats:italic> =0.068) as independent predictors of hemorrhagic transformation. Neither MRI lesion volumes nor severity of symptoms, but rather only an older age tended to be associated with parenchymal hemorrhage ( <jats:italic>P</jats:italic> =0.087). </jats:p> <jats:p> <jats:bold> <jats:italic>Conclusion—</jats:italic> </jats:bold> Our results further support the concept of a different pathogenesis for hemorrhagic transformation and parenchymal hemorrhage. Whereas hemorrhagic transformation should be regarded as a clinically irrelevant epiphenomenon of ischemic damage and reperfusion, parenchymal hemorrhage appears to be related to biologic effects of tissue plasminogen activator and other pre-existing pathologic conditions, which deserve further investigation. </jats:p>