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: 5.72).
10/2012; 44(1). DOI: 10.1161/STROKEAHA.112.674127
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)?
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.
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.
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.
Available from: Etheresia Pretorius
- "Resistant thrombi play a pivotal role in the pathogenesis of the conditions associated with thrombotic events like stroke, and recent research by Moftakhar et al. suggests that clot density can potentially be a useful discriminator in selecting the most appropriate reperfusion strategy for an individual patient . It should be noted that the interaction between fibrin fibers and RBCs is also observable in other diseases associated with thrombotic events that precede stroke, such as diabetes mellitus ; therefore, this fact suggests a cause and not the consequence of stroke. "
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BACKGROUND OR INTRODUCTION: Stroke is one of the most debilitating diseases causing morbidity and mortality worldwide. During ischemic stroke, erythrocytes undergo oxidative and proteolytic changes resulting not only in inflammation but also in changes in cellular rheology. During the event, fibrin fibers, which are typically a fine net, clot abnormally to form a clot of dense matted deposits (DMDs). This atypical coagulum causes blood cells to be trapped in the mesh.
Here we study red blood cell (RBC) ultrastructure in thromboembolic ischemic stroke using high resolution scanning electron microscopy.
We show that RBCs in patients change shape, with membrane extensions that form close interactions with the DMDs.
We suggest that the RBC membrane changes and resulting DMD interactions play a pivotal role in the persistent presence of thrombi. This ultrastructural observation might open a renewed debate regarding possible additional structural and biochemical roles of RBCs in the circulatory system.
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ABSTRACT: Despite high rates of early revascularization with intra-arterial stroke therapy, the clinical efficacy of this approach has not been clearly demonstrated. Neuroimaging biomarkers will be useful in future trials for patient selection and for outcomes evaluation. To identify patients who are likely to benefit from intra-arterial therapy, the combination of vessel imaging, infarct size quantification and degree of neurologic deficit appears critical. Perfusion imaging may be useful in specific circumstances, but requires further validation. For measuring treatment outcomes, surrogate biomarkers that appear suitable are angiographic reperfusion as measured by the modified Thrombolysis in Cerebral Infarction scale and final infarct volume.
Available from: stroke.ahajournals.org
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