Neurointervention.  2019 Sep;14(2):99-106. 10.5469/neuroint.2019.00080.

Dichotomizing Level of Pial Collaterals on Multiphase CT Angiography for Endovascular Treatment in Acute Ischemic Stroke: Should It Be Refined for 6-Hour Time Window?

• Woo HG
• Jung C
• Sunwoo L
• Bae YJ
• Choi BS
• Kim JH
• Kim BJ
• Han MK
• Bae HJ
• Jung S
• Cha SH

• KMID: 2458489
• DOI: http://doi.org/10.5469/neuroint.2019.00080

Abstract

PURPOSE
Although endovascular treatment is currently thought to only be suitable for patients who have pial arterial filling scores >3 as determined by multiphase computed tomography angiography (mpCTA), a cut-off score of 3 was determined by a study, including patients within 12 hours after symptom onset. We aimed to investigate whether a cut-off score of 3 for endovascular treatment within 6 hours of symptom onset is an appropriate predictor of good functional outcome at 3 months.
MATERIALS AND METHODS
From April 2015 to January 2016, acute ischemic stroke patients treated with mechanical thrombectomy within 6 hours of symptom onset were enrolled into this study. Pial arterial filling scores were semi-quantitatively assessed using mpCTA, and clinical and radiological parameters were compared between patients with favorable and unfavorable outcomes. Multivariate logistic regression analysis was then performed to investigate the independent association between clinical outcome and pial collateral score, with the predictive power of the latter assessed using C-statistics.
RESULTS
Of the 38 patients enrolled, 20 (52.6%) had a favorable outcome and 18 had an unfavorable outcome, with the latter group showing a lower mean pial arterial filling score (3.6±0.8 vs. 2.4±1.2, P=0.002). After adjusting for variables with a P-value of <0.1 in univariate analysis (i.e., age and National Institutes of Health Stroke Scale score at admission), pial arterial filling scores higher than a cut-off of 2 were found to be independently associated with favorable clinical outcomes (P=0.012). C-statistic analysis confirmed that our model had the highest prediction power when pial arterial filling scores were dichotomized at >2 vs. ≤2.
CONCLUSION
A pial arterial filling cut-off score of 2 as determined by mpCTA appears to be more suitable for predicting clinical outcomes following endovascular treatment within 6 hours of symptom onset than the cut-off of 3 that had been previously suggested.

Keyword

Stroke; Computed tomography angiography; Thrombectomy

MeSH Terms

Angiography*
Humans
Logistic Models
National Institutes of Health (U.S.)
Stroke*
Thrombectomy

Figure

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  Fig. 1. Pial arterial filling score within the symptomatic ischemic territory using multiphase CT angiography images. Top row: images of a patient with a left MCA M1 segment occlusion (arrow) and no delay of phase in filling in of peripheral vessels, but with the same prominence and extent. Second row: images of a patient with a right MCA M1 segment occlusion (arrow) and a delay of 1 phase in filling in of peripheral vessels, but with the same prominence and extent. Third row: images of a patient with a left MCA M1 segment occlusion (arrow) and a delay of 2 phases in filling in of peripheral vessels, but with the same prominence and extent. Fourth row: images of a patient with a right MCA M1 segment occlusion (arrow) and a delay of 1 phase in filling in of peripheral vessels, but with decreased prominence and extent. Fifth row: images of a patient with a right MCA M1 segment occlusion (arrow) and just a few vessels visible in any phase within the occluded vascular territory. Bottom row: images of a patient with a left MCA M1 segment occlusion (arrow) and no vessels visible in any phase within the ischemic vascular territory. CT, computed tomograpy; MCA, middle cerebral artery.

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  Fig. 2. Results of receiver operating characteristic analysis for investigating functional outcome using each dichotomized pial arterial filling score (>4 vs. ≤4, >3 vs. ≤3, and >2 vs. ≤2). AUC, area under the receiver-operating characteristic curve; CI, confidence interval.

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