Heterogeneity in infarct patterns and clinical outcomes following internal carotid artery occlusion

Abstract

Objective: To investigate whether the extent of infarction and clinical outcomes after internal carotid artery (ICA) occlusion depends on the additional occlusion of the middle cerebral artery (MCA).

Design: Using statistical parametric mapping, we compared infarct patterns in stroke patients.

Setting: A tertiary care hospital.

Patients: Patients with coexistent ICA and MCA occlusion (n = 25), isolated ICA occlusion (n = 20), and isolated MCA occlusion (n = 40).

Main outcome measure: Modified Rankin scale score. The independent effect of infarct type on clinical outcome was estimated using logistic regression, adjusting for age and sex.

Results: The mean age was 62.6 years (standard deviation [SD], 15.5 years) in patients with ICA and MCA occlusion, 64.3 years (SD, 12.9 years) in patients with isolated ICA occlusion, and 67.4 years (SD, 14.2 years) in patients with isolated MCA occlusion. Infarct patterns, volume (P = .13), and the proportion of patients with poor outcomes (P = .5) were similar between those with ICA and MCA occlusions and those with isolated MCA occlusion. Compared with the other 2 groups, those with isolated ICA occlusion were less likely to have infarction of the insula (P < .001) and superior temporal lobe (P < .001) and had smaller infarct volume and lower modified Rankin scale scores (all P < .05). Compared with those with isolated ICA occlusion, the risk of poor clinical outcome was greater in those with coexistent ICA and MCA occlusion (P = .02) and those with isolated MCA occlusion (P = .06) independent of age and sex.

Comments: Patients with ICA occlusion but without coexistent MCA occlusion have different infarct patterns, less extensive infarcts, and better clinical outcomes than those with coexistent MCA occlusion or MCA occlusion alone. It may not be warranted to exclude such patients from acute stroke trials.