ISC: MRI may help decide therapy in unclear-onset stroke patients
MRI can help identify which patients with unclear-onset stroke might benefit from therapeutic intervention, according to research presented Feb. 10 at the American Stroke Association’s International Stroke Conference 2011 in Los Angeles.
Patients with unclear-onset stroke account for one-quarter of all ischemic strokes. However, they have been excluded from standard thrombolysis therapy, which is effective at reducing disability up to 4.5 hours after onset. Previous studies have indicated controversial results among this population, according to Dong-Wha Kang, MD, PhD, associate professor of neurology at Asan Medical Center at University of Ulsan College of Medicine in Seoul, South Korea.
Kang and colleagues hypothesized that MRI-based thrombolysis is feasible and could achieve acceptable safety and efficacy outcomes. To test their hypothesis, the researchers screened 430 unclear-onset stroke patients at six university hospitals within six hours of detecting symptoms.
Patients underwent diffusion-perfusion MRI, and researchers analyzed image datasets to determine which patients met MRI-specific eligibility criteria of reperfusion therapy: perfusion-diffusion mismatch of more than 20 percent, absence of early infarct on more than one-third of middle cerebral artery territory on diffusion-weighted imaging and absence of well-developed parenchymal hyperintensity of FLAIR or T2 images.
Researchers determined that 83 patients with a median age of 67 years were eligible for thrombolyisis therapy, consisting of tissue plasminogen activator (tPA), direct administration of urokinase (not available in the U.S.) to blocked vessels or both. Some patients also underwent mechanical clot disruption or stenting.
They found three groups were likely to fare more poorly with treatment: female patients, patients with a more severe initial assessment and those treated at two centers lacking previous experience in thrombolysis for unclear-onset stroke.
The primary clinical endpoint was a “good” outcome, or a modified Rankin Scale of 0 to 2 at three months. Forty-five percent of patients undergoing therapy had at least a good clinical outcome, defined as ranging from no symptoms to slight disability with curtailed activity; and nearly 29 percent were able to return to usual activities with little or no impairment.
The researchers conducted multivariate analysis to identify independent factors associated with poor clinical outcomes, measured by modified Rankin Scale scores of 3 to 6.
Kang acknowledged that the study omitted a comparison group. The next step for the researchers is to compare the outcomes among their study cohort with those of comparable but untreated patients in stroke registries.
Patients with unclear-onset stroke account for one-quarter of all ischemic strokes. However, they have been excluded from standard thrombolysis therapy, which is effective at reducing disability up to 4.5 hours after onset. Previous studies have indicated controversial results among this population, according to Dong-Wha Kang, MD, PhD, associate professor of neurology at Asan Medical Center at University of Ulsan College of Medicine in Seoul, South Korea.
Kang and colleagues hypothesized that MRI-based thrombolysis is feasible and could achieve acceptable safety and efficacy outcomes. To test their hypothesis, the researchers screened 430 unclear-onset stroke patients at six university hospitals within six hours of detecting symptoms.
Patients underwent diffusion-perfusion MRI, and researchers analyzed image datasets to determine which patients met MRI-specific eligibility criteria of reperfusion therapy: perfusion-diffusion mismatch of more than 20 percent, absence of early infarct on more than one-third of middle cerebral artery territory on diffusion-weighted imaging and absence of well-developed parenchymal hyperintensity of FLAIR or T2 images.
Researchers determined that 83 patients with a median age of 67 years were eligible for thrombolyisis therapy, consisting of tissue plasminogen activator (tPA), direct administration of urokinase (not available in the U.S.) to blocked vessels or both. Some patients also underwent mechanical clot disruption or stenting.
They found three groups were likely to fare more poorly with treatment: female patients, patients with a more severe initial assessment and those treated at two centers lacking previous experience in thrombolysis for unclear-onset stroke.
The primary clinical endpoint was a “good” outcome, or a modified Rankin Scale of 0 to 2 at three months. Forty-five percent of patients undergoing therapy had at least a good clinical outcome, defined as ranging from no symptoms to slight disability with curtailed activity; and nearly 29 percent were able to return to usual activities with little or no impairment.
The researchers conducted multivariate analysis to identify independent factors associated with poor clinical outcomes, measured by modified Rankin Scale scores of 3 to 6.
Kang acknowledged that the study omitted a comparison group. The next step for the researchers is to compare the outcomes among their study cohort with those of comparable but untreated patients in stroke registries.