Abstract T MP34: Correlates of Clot Length Assessed by Thin-Section CT in a Consecutive Series of Stroke Patients
Purpose: Thin-section (≤2.5mm) NCCT can be used to reliably measure clot length in anterior circulation occlusions. Clots ≥8mm long have a low probability of recanalization with IV rtPA alone, and a majority in the proximal anterior circulation meet this criterion. However, previous studies have had sampling limitations, and correlates of clot length remain to be identified.
Methods: Data from an ongoing multicenter review were used to explore potential correlates of clot length. Eligible patients were those who presented within 8 hours of onset, had thin-section NCCT, and evidence of ICAT, M1, or M2 MCA occlusion. Variables of interest were age, sex, baseline NIHSS, ASPECTS, occlusion level, IV rtPA dose pre vs post scan, time from stroke onset to imaging, and IA recanalization. Univariate analyses were conducted with clot length as a dichotomized variable (≥8mm vs <8mm), and multivariate logistic regression was used to determine predictors.
Results: Consecutive stroke admissions between August 2011 and March 2013 were reviewed at 3 US centers for eligibility, and 176 patients met criteria (mean age=71.2 years; 56% female; mean baseline NIHSS=17.3). Of the primary occlusions, 22.7% were ICAT, 55.2% M1, and 22.1% M2 MCA.
Hyperdense clot was visible in 88% (154/176) of cases. Patients with clot lengths ≥8mm had a higher mean baseline NIHSS (18 vs 14.9, p = .01), and lower mean ASPECTS (5.9 vs. 7.8, p=.003). Across occlusion levels, 97%, 75%, and 43% of ICAT, M1, and M2 MCA clots were ≥8mm respectively (p<.0001). Of these variables, only occlusion level was a significant multivariate predictor of clot length (OR=3.1; 95% CI,1.4-6.6 per proximal level, p=.005). Among patients who went on to IA therapy (n=62), clot length was not significantly associated with successful recanalization.
Conclusion: This analysis further validates the use of thin-section NCCT for measuring hyperdense thrombus, and suggests occlusion location is an important determinant of clot length, which may explain IV rtPA inefficacy in large vessels. It remains to be determined whether clot length is associated with the probability of successful mechanical thrombectomy by IA adjunctive therapy.
Author Disclosures: A. Yoo: Research Grant; Significant; National Institutes of Health, Penumbra Inc., Remedy Pharmaceuticals. D. Frei: Honoraria; Modest; Penumbra Inc.. D. Loy: None. D. Heck: None. M. Aceves: Employment; Significant; Penumbra Inc. H. Buell: Employment; Significant; Penumbra Inc. S. Kamalian: Research Grant; Significant; GE Healthcare, Department of Defense, CIMIT. L. Morais: None. A. Bitner: Honoraria; Modest; Penumbra Inc. A. Bose: Employment; Significant; Penumbra Inc. S. Sit: Employment; Significant; Penumbra Inc..
- © 2014 by American Heart Association, Inc.