Maximal Admission Core Lesion Compatible With Favorable Outcome in Acute Stroke Patients Undergoing Endovascular Procedures.

BACKGROUND AND PURPOSE: Multiparametric imaging is meant to identify nonreversible lesions and predict on admission the minimum final infarct volume, a strong predictor of outcome. We aimed to confirm this hypothesis and define the maximal admission lesion volume compatible with favorable outcome (MALCOM).

METHODS: We studied patients with internal carotid artery/middle cerebral artery occlusion selected with multiparametric computed tomography/magnetic resonance imaging, who underwent endovascular procedures. Admission infarct core was measured on initial cerebral blood volume-computed tomography perfusion or diffusion weighted imaging-magnetic resonance imaging. We defined percentage of lesion growth (final lesion admission core/admission core) and MALCOM: cutoff admission core volume above which probability of modified Rankin Scale 0 to 2 is <10%.

RESULTS: Fifty-seven patients were studied (29 magnetic resonance imaging and 28 computed tomography perfusion). Mean core volume was 28±22 mL, and recanalization thrombolysis in cerebral ischemia 2b-3 was 77%. At 24 hours, mean infarct volume was 64±97 mL, and at 3 months modified Rankin Scale 0 to 2 was 45%. Median lesion growth was smaller in recanalizers (16.7% versus 198.3%; P<0.01). MALCOM was 39 mL. When recanalization was achieved, 64% of patients within MALCOM (<39 mL) achieved favorable outcome, whereas despite recanalization only 12% of patients beyond MALCOM (>39 mL) achieved modified Rankin Scale 0 to 2 (P=0.01). A regression model adjusted for age and recanalization showed that the only predictor of favorable outcome was having admission core lesion below MALCOM (OR: 9.3, 95% CI: 1.9-46.4; P<0.01). Analysis according to imaging modality showed that computed tomography-cerebral blood volume allowed larger MALCOM (42 mL) than magnetic resonance-diffusion weighted imaging (29 mL). In octogenarians, MALCOM (15 mL) was lower in younger patients (40 mL).

CONCLUSIONS: Admission lesion core is associated with final infarct volume and is a strong predictor of favorable outcome. MALCOM according to imaging modality and patient age could be set and used on admission to select candidates for endovascular procedures.