Impact of collaterals on successful revascularization in Solitaire FR with the intention for thrombectomy

Abstract

Background and purpose: Collaterals at angiography before endovascular therapy were analyzed to ascertain the effect on a novel end point of successful revascularization without symptomatic hemorrhage in the Solitaire FR With the Intention for Thrombectomy (SWIFT) study.

Methods: Collateral grade (American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology) on baseline angiography was independently assessed, blind to other data, with statistical analyses delineating the relationship with clinical, laboratory, and imaging parameters.

Results: Angiographic data on collaterals were available in 119 of 144 subjects (mean age, 67±12 years; 52% woman; median National Institutes of Health Stroke Scale, 18 [range, 8-28]). Worse collaterals were noted in subjects with elevated baseline blood glucose (P=0.013) and those with elevated baseline systolic blood pressure (P=0.039). Multivariate predictors of partial or worse collaterals included absence of prior hypertension (odds ratio, 4.049, P=0.012), smoking history (odds ratio, 3.822; P=0.013), and higher blood glucose (odds ratio, 1.017; P=0.022). Collaterals were strongly related to Alberta Stroke Program Early CT Score (ASPECTS) at baseline (0-1: median 8 [3-10]; 2-9 [5-10]; 3-9 [7-10]; 4-9 [8-10]; P<0.001) and 24 hours (0-1: median 1 [0-5]; 2-6 [0-10]; 3-8 [0-10]; 4-8 [4-8]; P<0.001). Better collaterals were linked with Thrombolysis in Cerebral Infarction 2b/3 reperfusion (P=0.019), better median National Institutes of Health Stroke Scale at day 7/discharge (P<0.001), and better day 90 modified Rankin Scale (P<0.001). Better collateral grade was associated with successful revascularization without symptomatic hemorrhage, mean 2.3 (95% confidence interval, 2.1-2.5) versus 1.9 (95% confidence interval, 1.7-2.2), P=0.021.

Conclusions: Better collaterals were associated with lower glucose, lower blood pressure, smaller baseline infarcts in SWIFT, and greater likelihood of successful revascularization without hemorrhage and good clinical outcomes.

Clinical trial registration url: http://www.clinicaltrials.gov. Unique identifier: NCT01054560.

Keywords: collaterals; endovascular therapy; revascularization; stroke.

Figure 1

Examples of the broad distribution of American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology collateral grades noted in Solitaire FR With the Intention for Thrombectomy. Angiographic collaterals are demonstrated in 5 different cases: revealing grade 0 or no collaterals in right MCA occlusion, marginal or grade 1 collaterals in left MCA occlusion, grade 2 or partial collaterals in left MCA occlusion, grade 3 or slow but complete collaterals in right middle cerebral artery (MCA) occlusion, and grade 4 or rapid and complete collaterals in right MCA occlusion. ARCH indicates aortic arch injection; and LICA, left internal carotid artery.

Figure 2

Alberta Stroke Program Early CT Score (ASPECTS) and collateral grade correlation in case examples. In right middle cerebral artery occlusion, preserved ASPECTS (A) is associated with robust or grade 4 collaterals (B). In a left middle cerebral artery occlusion, decreased ASPECTS (C) is associated with marginal or grade 1 collaterals (D). LCCA indicates left common carotid artery; and RCCA, right common carotid artery.

Figure 3

Poor collaterals in a case of left middle cerebral artery occlusion (A) is followed by extensive ischemia and hemorrhagic transformation (B) after recanalization with marginal reperfusion. In another case of left middle cerebral artery occlusion, robust collaterals (C) is followed by complete or Thrombolysis in Cerebral Infarction 3 reperfusion (D) and good clinical outcome. LCCA indicates left common carotid artery.