LOS ANGELES – In acute ischemic stroke patients with small perfusion lesions of less than 15 mL, involvement of the corticospinal tract (CST) may help guide the decision whether to treat with alteplase.
Specifically, patients with hypoperfusion in the CST, but without CST infarction, were more likely to have a modified Rankin Scale score (mRS) of 0-2 at 90 days after treatment with alteplase. Patients with no CST involvement, or with a CST infarct, had worse outcomes with treatment.
The better outcomes “might indicate that hypoperfused CST tissue at baseline could be salvaged by timely reperfusion,” said Min Lou, MD, PhD, vice chair of neurology at Zhejiang University, Hangzhou, China, during her presentation of the study at the International Stroke Conference sponsored by the American Heart Association.
Previous studies have left physicians uncertain what to do with patients presenting with mild stroke, especially strokes that are judged to be potentially disabling despite a low National Institutes of Health Stroke Scale (NIHSS) score. These patients have a lower risk of hemorrhagic conversion, estimated at 0%-2%.
A meta-analysis showed that alteplase treatment in patients with a baseline NIHSS score of 0-4 was associated with a 48% increase in the chance of an excellent outcome. But another study showed that, among patients with a perfusion lesion smaller than 15 mL, treatment with alteplase was less likely than no treatment at all to confer an excellent outcome.
“The challenge is to identify what kind of minor stroke patient would benefit from thrombolysis therapy,” said Dr. Lou.
The researchers analyzed data from the International Stroke Perfusion Imaging Registry (INSPIRE) database, selecting 412 patients with an acute perfusion lesion less than 15 mL who had undergone computed tomography perfusion or magnetic resonance perfusion imaging within 4.5 hours of symptom onset, had had the scan repeated at 24 hours, and who were followed up at 90 days.
Among the patients, 248 were treated with alteplase, and 164 were not. The alteplase-treated group had a mean NIHSS score of 5.0, compared with 4.0 in the untreated group (P = .001). CST hypoperfusion was more common in the treated group (32.3% versus 15.9%, P less than .001), as was CST infarction (14.9% versus 5.5%, P = .004) and 24-hour intracerebral hemorrhage (ICH) (9.3% versus 0.6%, P less than .001).
The researchers divided subjects into three groups: no CST lesion (306 patients), CST hypoperfusion with no CST infarct (60), and CST infarct (46). The 24-hour ICH frequency varied between the groups, with the highest frequency in the CST infarct group (15.2%), followed by the CST hypoperfusion with no infarct group (10.0%), and the no CST lesion group (3.6%, P = .002).
At 90 days, higher frequency of an mRS score of 0-1 was only associated with alteplase treatment in the CST hypoperfusion with no infarct group (76.7% versus 47.1%, P = .035).
The reverse was true in the other groups: No treatment was associated with better odds of an mRS score of 0-1 in the group with no CST lesion (87.7% versus 79.8%, P = .067) and particularly in the group with CST infarct (88.9% versus 32.4%, P = .006).
The study is limited by the fact that it is a retrospective analysis, the investigators cautioned.
The National Natural Science Foundation of China funded the study. Dr. Lou reported having no financial disclosures.