Article

O-006 Analysis of Screened Patients from the Penumbra THERAPY Trial: Correlations of Clot Length Assessed by Thin-Section CT in a Sequential Series of Acute Stroke Patients

Authors:
  • radiology imaging associates
  • Texas Stroke Institute
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Purpose Thin-section (≤2.5 mm) NCCT is a dependable method for measurement of clot length in documented anterior circulation occlusions. A majority of clots in the proximal anterior circulation are ≥8 mm, which have low probability of revascularization with IV rtPA alone. Nevertheless, past studies have had sampling restrictions, and correlations of clot length continue to be classified. Methods Data was captured to investigate potential correlates of clot length from an ongoing multicenter review. Patients were eligible if presented within 8 h of onset, had thin-section NCCT admission imaging, and evidence of ICA-T, M1, or M2 MCA occlusion. All patients had their occlusions documented by CTA, angiography, or MRI. Patients did not necessarily have thrombectomy performed. Baseline characteristics of interest included age, sex, baseline NIHSS, ASPECTS, occlusion level, IV rtPA dose pre vs. post scan, time from stroke onset to imaging, and IA recanalization. Univariate analyzes were implemented with clot length as a dichotomized variable (≥8 mm vs <8 mm), and multivariate logistic regression was used to define predictors. Results Consecutive stroke admissions were reviewed at 3 US centers between August 2011 and March 2013 for eligibility, and 175 patients met criteria. Mean age was 70 years old; 56% were female. Median baseline NIHSS score was 17 (IQR 12–22). The level of occlusion was distributed such that 23% were ICA-T, 54% M1, and 23% M2 MCA. Of the 175 confirmed occlusions, hyperdense clot was visible in 89% (156/175) of cases. Visible clot ranged from 2 mm to 65 mm, while mean length was 14 mm. There were 66% (115/175) patients with clot lengths ≥8 mm. In comparing clot length to occlusion level, 90% of ICA-T, 69% of M1, and 34% of M2 occlusions were ≥8 mm (p < 0.001), with median clot lengths of 20.5, 14.1, and 7.2, respectively. The only significant multivariate predictor of clot length was the occlusion level (OR, 95% CI =3.9 (2.2–6.9) per step from M2 to M1 to ICA-T, p < 0.0001). Conclusion This analysis further supports the idea of measuring hyperdense thrombus by use of thin-section NCCT. Occlusion site is a key predictor of clot length, which may explain the relative ineffectiveness of IV rtPA in more proximal anterior circulation large vessels. These findings suggest a sizeable population who may benefit from a bridging approach. Disclosures D. Frei: 3; C; Penumbra Inc. 4; C; Penumbra Inc. D. Heck: None. A. Yoo: 1; C; National Institutes of Health, Penumbra Inc., Remedy Pharmaceuticals. D. Loy: None. H. Buell: 5; C; Penumbra Inc. S. Kamalian: 1; C; GE Healthcare, Department of Defense, CIMIT. L. Morais: None. A. Bitner: 3; C; Penumbra Inc. D. Meyer: 5; C; Penumbra Inc. S. Kuo: 5; C; Penumbra Inc. A. Bose: 4; C; Penumbra Inc. 5; C; Penumbra Inc. S. Sit: 4; C; Penumbra Inc. 5; C; Penumbra Inc.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... HMCAS clot length is dependent on the site of the occlusion, with more proximal clots being longer. 17 Patients with more proximal HMCAS are less likely to improve clinically, and HMCAS disappearance is less likely than those with a distally located HMCAS. 1,18 Furthermore, our population age is older than those included in previous studies. ...
Article
Full-text available
Disappearance of the hyperdense middle cerebral artery sign (HMCAS) following intravenous thrombolysis for ischaemic stroke is associated with improved outcome. Debate exists over which radiological thrombus characteristics can predict disappearance of the HMCAS after thrombolysis such as vessel attenuation or extent of thrombus length. Methods Ischaemic stroke patients treated with intravenous thrombolysis from our hospital were entered into a European registry. Patient demographics, stroke severity pre- and 24 hours post-thrombolysis were recorded. Patients with HMCAS were identified from the registry using records from 2010–2013. Images from the pre and post-thrombolysis computed tomography scan were measured. Thrombus characteristics (length and attenuation), extent of ischaemic change and clinical outcome (stroke severity and 3 month survival) were compared between patients with and without HMCAS disappearance. Logistic regression analysis was performed to identify predictors of HMCAS disappearance. Results HMCAS was present in 88/315 (28%) of thrombolysed ischaemic stroke patients. 36/88 (41%) of patients had thrombus disappearance 24 hours after thrombolysis. HMCAS disappearance was associated with reduced stroke severity, less radiological ischaemic change, and higher 3 month survival (87% vs 56%). Median thrombus length was shorter in the HMCAS disappearance group (11 vs 17 mm, p = 0.0004), but no significant difference in vessel attenuation was observed (48 vs 51 Hounsfield Units, p = 0.25). HMCAS disappearance occurred in 73% of cases where HMCAS length was < 10 mm, 38% when length was 10–20 mm, and 21% if > 20 mm. Thrombus length was the only independent predictor of HMCAS disappearance (odds ratio 0.90 per mm; 95% CI 0.84-0.96, p = 0.01). Conclusion Disappearance of HMCAS is associated with better clinical and radiological outcomes. A shorter thrombus is more likely to disappear post-thrombolysis. The data highlight the limitation of intravenous thrombolysis in patients with longer hyperattenuated vessels, and the potential role for clot retrieval in such patients.
... Radiologists from the University of Kiel had found in a retrospective case series that recanalization was never observed in iv-tPA-treated patients with a thrombus length of more than 8 mm as measured in thin-slice nonenhanced CT images. Size of clots >8 mm has therefore become a selection criterion for intraarterial interventional treatment and is even used as an inclusion criterion of a randomized trial comparing intravenous tPA combined with mechanical thrombectomy and intravenous tPA alone [4,5]. The association between clot length and early recanalization was confirmed in a recent study assessing the vessel status with CT angiography (CTA)/magnetic resonance angiography (MRA) before thrombolysis and catheter angiography after thrombolysis. ...
Article
Full-text available
In acute stroke, imaging provides different technologies to demonstrate stroke subtype, tissue perfusion and vessel patency. In this review, we highlight recent clinical studies that are likely to guide therapeutic decisions. Clot length in computed tomography (CT) and clot burden in MR, imaging of leptomeningeal collaterals and indicators for active bleeding are illustrated. Imaging-based concepts for treatment of stroke at awakening and pre-hospital treatment in specialized ambulances offer new potentials to improve patient outcome.
... Radiologists from the University of Kiel had found in a retrospective case series that recanalization was never observed in iv-tPA-treated patients with a thrombus length of more than 8 mm as measured in thin-slice nonenhanced CT images. Size of clots >8 mm has therefore become a selection criterion for intraarterial interventional treatment and is even used as an inclusion criterion of a randomized trial comparing intravenous tPA combined with mechanical thrombectomy and intravenous tPA alone [4,5]. The association between clot length and early recanalization was confirmed in a recent study assessing the vessel status with CT angiography (CTA)/magnetic resonance angiography (MRA) before thrombolysis and catheter angiography after thrombolysis. ...
Article
Full-text available
Cerebral imaging is essential to differentiate the pathologies behind acute stroke. Excluding hemorrhage with a native CT is a prerequisite before thrombolytic drugs can be administered. With stroke MRI, vessel occlusion, ischemia and infarction can be visualized. This detailed diagnostic information can facilitate the decision for or against thrombolysis. Analysis of FLAIR and diffusion-weighted images enables the identification of patients in an early time window after ictus and is currently used in randomized trials of wake-up stroke.
ResearchGate has not been able to resolve any references for this publication.