Collateral score complements clot location in predicting the outcome of intravenous thrombolysis.

BACKGROUND AND PURPOSE: Collateral circulation is an important determinant of stroke outcome. We studied the impact of leptomeningeal collateral circulation with respect to the location of the thrombus in predicting the clinical outcome of patients treated with intravenous thrombolytic therapy (<3 hours) in a retrospective cohort. MATERIALS AND METHODS: Anterior circulation thrombus was detected with CT angiography in 105 patients. Baseline clinical and imaging information was collected, and the site of the occlusion was recorded. Collaterals were assessed by using a 5-grade collateral score and were entered into logistic regression analysis to predict favorable clinical outcome (3-month modified Rankin Scale score of 0-2). RESULTS: Two-thirds of patients with a proximal occlusion displayed poor collateral filling (collateral score 0-1), whereas in more distal clot locations, approximately one-third had poor collaterals. Only 36% of patients with a proximal occlusion and good collaterals experienced favorable clinical outcome. In multivariate analysis, both clot location and collateral score were highly significant (P = .003 and P = .001) and independent predictors of favorable clinical outcome. Good collateral status increased the odds of favorable clinical outcome about 9-fold (OR = 9.3; 95% CI, 2.4-35.8). After dichotomization, a distal clot location had a larger odds ratio (OR = 13.3; 95% CI, 3.0-60.0) compared with the odds ratio of good collaterals (OR = 5.9; 95% CI, 1.8-19.0). CONCLUSIONS: A proximal occlusion in the anterior circulation is associated with poorer collateral status compared with a more distal occlusion. Both the clot location and collateral score are important and independent predictors of favorable clinical outcome of hyperacute stroke treated with intravenous thrombolysis. The location of the clot is a stronger determinant of the outcome than the collateral score.

Location of the clot and outcome of perfusion defects in acute anterior circulation stroke treated with intravenous thrombolysis.

BACKGROUND AND PURPOSE: The location of the clot is a major determinant of ischemic stroke outcome. We studied the impact of the location (ICA, proximal M1 segment of the MCA, distal M1 segment, and M2 segment and more distally) of the clot on the CT perfusion parametric maps, the mismatch ratio, the amount of salvaged brain tissue, and the imaging and clinical outcomes in a retrospective acute (<3 hours) stroke cohort treated with intravenous thrombolysis. MATERIALS AND METHODS: We reviewed 105 patients who underwent admission multimodal CT that revealed an occluded vessel on CTA. CT perfusion was successfully performed in 58 patients (55%). Differences among the parameters in different vessel positions were studied with the ANCOVA by using onset-to-imaging time as a covariate followed by pair-wise testing. RESULTS: There were no significant differences in potential confounding variables among the groups. A clot proximal to the M2 segment produced a significantly larger defect on the MTT map. A clot in the ICA resulted in a significantly larger CBV lesion compared with the distal M1 segment, the M2 segment, and the M3 segment. In general, a more proximal thrombus created a larger CBV defect. The fraction of penumbra that was salvaged at 24 hours was higher in the more distal vessel positions. CONCLUSIONS: Admission CBV defects are larger in proximal vessel occlusions. More of the penumbra can be salvaged if the occlusion is located distally. This effect seems to reach a plateau in the distal M1 segment of the MCA.

The mid-M1 segment of the middle cerebral artery is a cutoff clot location for good outcome in intravenous thrombolysis.

BACKGROUND AND PURPOSE: We studied the impact of the location of the thrombus (internal carotid artery, proximal M1 segment, distal M1 segment, M2 segment, and M3 segment of the middle cerebral artery) in predicting the clinical outcome of patients treated with intravenous thrombolytic therapy (<3 h) in a retrospective cohort. METHODS: Anterior circulation thrombus was detected with computed tomography angiography in 105 patients. Baseline clinical and radiological information was collected and entered into logistic regression analysis to predict favorable clinical outcome (3-month modified Rankin Scale from 0 to 2 was a primary outcome measure). RESULTS: Three months after stroke, there was a significant increase in mortality (32% vs. 3%, P < 0.001) and functional dependency (82% vs. 29%, P < 0.001) in patients with internal carotid artery or proximal M1 segment of the middle cerebral artery thrombus compared to a more distal occlusion. In the regression analysis, after adjusting for National Institutes of Health Stroke Scale, age, sex, and onset-to-treatment time, the clot location was an independent predictor of good clinical outcome (P = 0.001) and exhibited dose-response type behavior when moving from a proximal vessel position to a more distal one. When the location was dichotomized, a cutoff between the proximal and the distal M1 segments best differentiated between good and poor clinical outcome (OR = 16.0, 95% CI 3.9-66.2). CONCLUSIONS: The outcome of acute internal carotid artery or proximal M1 segment of the middle cerebral artery occlusion is generally poor even if treated with intravenous thrombolysis. Alternative revascularization strategies should be considered. Vascular imaging at the admission is required to guide this decision.