Density of Thrombus on Admission CT Predicts Revascularization Efficacy in Large Vessel Occlusion Acute Ischemic Stroke

From Departments of Radiology and Biomedical Imaging, Neurology, and Neurological Surgery, University of California, San Francisco, CA.
Stroke (Impact Factor: 6.02). 10/2012; 44(1). DOI: 10.1161/STROKEAHA.112.674127
Source: PubMed

ABSTRACT BACKGROUND AND PURPOSE: Can lysability of large vessel thrombi in acute ischemic stroke be predicted by measuring clot density on admission nonenhanced CT (NECT), postcontrast enhanced CT, or CT angiogram (CTA)? METHODS: We retrospectively studied 90 patients with acute large vessel ischemic strokes treated with intravenous (IV) tPA, intra-arterial (IA) tPA, and/or mechanical thrombectomy devices. Clot density [in Hounsfield unit (HU)] was measured on NECT, postcontrast enhanced CT, and CTA. Recanalization was assessed by the Thrombolysis in Cerebral Infarction grading system (TICI) on digital subtraction angiography. RESULTS: Thrombus density on preintervention NECT correlated with postintervention TICI grade regardless of pharmacological (IV tPA r=0.69, IA tPA r=0.72, P<0.0001) or mechanical treatment (r=0.73, P<0.0001). Patients with TICI≥2 demonstrated higher HU on NECT (mean corrected HU IV tPA=1.58, IA tPA=1.66, mechanical treatment=1.7) compared with patients with TICI<2 (IV tPA=1.39, IA tPA=1.4, mechanical treatment=1.3) (P=0.01, 0.006, <0.0001 respectively). There was no association between recanalization and age, sex, baseline National Institute of Health Stroke Scale, treatment method, time to treatment, or clot volume. CONCLUSIONS: Thrombi with lower HU on NECT appear to be more resistant to pharmacological lysis and mechanical thrombectomy. Measuring thrombus density on admission NECT provides a rapid method to analyze clot composition, a potentially useful discriminator in selecting the most appropriate reperfusion strategy for an individual patient.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Proximal artery occlusions (PAO) recanalize in only a small percentage of acute ischemic stroke (AIS) patients treated with intravenous tissue plasminogen activator (IV tPA) alone, yet the benefits of adjunctive or substitutive intra-arterial therapy (IAT) in this patient subgroup are not well established. We evaluated early poststroke outcomes in a cohort of AIS patients with PAO categorized as "likely to benefit'' (LTB) from IAT using prespecified criteria. Methods: Using a prespecified protocol, 193 patients from our institutional stroke database admitted between January 1, 2007, and December 31, 2011, were prospectively deemed LTB from IAT. Logistic regression was used to determine independent predictors of favorable (discharge to home or acute rehabilitation) versus unfavorable (discharge to skilled nursing facility, hospice, or in-hospital mortality) outcome. Results: Of the patients included, 29.5% received IV tPA only, 11.4% underwent IAT only, and 37.8% had both. Overall in-hospital mortality was 19.2%. In a univariate analysis, age (odds ratio [OR], .95; 95% confidence interval [CI],.93-. 98), IV tPA (OR, 2.3; 95% CI, 1.2-4.3), and history of atrial fibrillation (OR, .5; 95% CI,.28-. 97) were associated with outcome. Effect of IAT was not statistically significant (OR, 1.3; 95% CI,.7-2.3; P = .4). In multivariate analysis, the only independent predictor of favorable outcome was IV tPA administration (OR, 2.4; 95% CI, 1.2-5.0). The odds of favorable poststroke outcome were significantly lowered (OR, .3; 95% CI,.1-. 6; P =.0006) in those receiving neither IV tPA nor IAT. Conclusions: In AIS patients with PAO thought most likely to benefit from IAT, IV tPA independently predicted favorable outcomes. These data reinforce the recommendation to provide early IV tPA to all eligible patients.
    Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 09/2014; 23(10). DOI:10.1016/j.jstrokecerebrovasdis.2014.03.020 · 1.99 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study aims to investigate diagnostic sensitivity and reliability for the detection of middle cerebral artery occlusion (MCAO) on non-contrast-enhanced computed tomography (NECT) by visual assessment (VA), Hounsfield unit (HU) measurement, calculation of the Hounsfield unit/hematocrit (HU/Hct) ratio, and combination of visual assessment and attenuation measurement (VA + HU).
    Neuroradiology 10/2014; DOI:10.1007/s00234-014-1443-y · 2.37 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Early recanalization of occluded vessels in stroke is closely associated with improved clinical outcome. Microbubble-enhanced sonothrombolysis is a promising therapy to improve recanalization rates and reduce the time to recanalization. Testing any thrombolytic therapy requires a model of thromboembolic stroke, but to date these models have been highly variable with regards to clot stability. Here, we developed a model of thromboembolic stroke in rats with site-specific delivery of platelet-rich clots (PRC) to the main stem of the middle cerebral artery (MCA). This model was used in a subsequent study to test microbubble-enhanced sonothrombolysis. In Study 1 we investigated spontaneous recanalization rates of PRC in vivo over 4 hours and measured infarct volumes at 24 hours. In Study 2 we investigated tPA-mediated thrombolysis and microbubble-enhanced sonothrombolysis in this model. Study 1 demonstrated stable occlusion out to 4 hours in 5 of 7 rats. Two rats spontaneously recanalized at 40 and 70 minutes post-embolism. Infarct volumes were not significantly different in recanalized rats, 43.93 ± 15.44% of the ischemic hemisphere, compared to 48.93 ± 3.9% in non-recanalized animals (p = 0.7). In Study 2, recanalization was not observed in any of the groups post-treatment. Site specific delivery of platelet rich clots to the MCA origin resulted in high rates of MCA occlusion, low rates of spontaneous clot lysis and large infarction. These platelet rich clots were highly resistant to tPA with or without microbubble-enhanced sonothrombolysis. This resistance of platelet rich clots to enhanced thrombolysis may explain recanalization failures clinically and should be an impetus to better clot-type identification and alternative recanalization methods.