Large Volumes of Critically Hypoperfused Penumbral Tissue Do Not Preclude Good Outcomes After Complete Endovascular Reperfusion: Redefining Malignant Profile

Background and purpose: Acute ischemic stroke patients with large volumes of severe hypoperfusion (Tmax>10 s>100 mL) on magnetic resonance imaging have a higher likelihood of intracranial hemorrhage and poor outcomes after reperfusion. We aim to evaluate the impact of the extent of Tmax>10 s CTP lesions in patients undergoing successful treatment.

Methods: Retrospective database review of endovascular acute ischemic stroke treatment between September 2010 and March 2015 for patients with anterior circulation occlusions with baseline RAPID CTP and full reperfusion (mTICI 3). The primary outcome was the impact of the Tmax>10 s lesion spectrum on infarct growth. Secondary safety and efficacy outcomes included parenchymal hematomas and good clinical outcomes (90-day modified Rankin Scale score, 0-2).

Results: Of 684 treated patients, 113 patients fit the inclusion criteria. Tmax>10 s>100 mL patients (n=37) had significantly higher baseline National Institutes of Health Stroke Scale (20.7±3.8 versus 17.0±5.9; P<0.01), more internal carotid artery terminus occlusions (29% versus 9%; P=0.02), and larger baseline (38.6±29.6 versus 11.7±15.8 mL; P<0.01) and final (60.7±60.0 versus 29.4±33.9 mL; P<0.01) infarct volumes when compared with patients without Tmax>10 s>100 mL (n=76); however, the 2 groups were otherwise well balanced. There were no significant differences in infarct growth (22.1±51.6 versus 17.8±32.4 mL; P=0.78), severe intracranial hemorrhage (PH2: 2% versus 4%; P=0.73), good outcomes (90-day mRS score, 0-2: 56% versus 59%; P=0.83), or 90-day mortality (16% versus 7%; P=0.28). On multivariate analysis, only baseline National Institutes of Health Stroke Scale (odds ratio, 1.19; 95% confidence interval, 1.06-1.34; P<0.01) and baseline infarct core volume (odds ratio, 1.05; 95% confidence interval, 1.02-1.08; P<0.01) were independently associated with Tmax>10 s>100 mL. There was no association between Tmax>10 s>100 mL with any PH, good outcome, or infarct growth.

Conclusions: In the setting of limited baseline ischemic cores, large Tmax>10 s lesions on computed tomographic perfusion do not seem to be associated with a higher risk of parenchymal hematomas and do not preclude good outcomes in patients undergoing endovascular reperfusion with contemporary technology.