Collateral score as a prognostic marker in acute anterior circulation stroke: A multiphase computed tomography angiography analysis

Objectives: Cerebral collateral circulation is the main compensatory phenomenon that maintains the ischemic penumbra viable. Early and fast imaging of collaterals plays a major role in aiding revascularisation therapies. Recent studies showed the advantage of multiphasic computed tomographic angiography (mCTA) over single-phase computed tomographic angiography in an acute ischemic stroke (AIS) patient. In our study, collateral status is evaluated prospectively and assessed for its association with the outcome of the patient. The objectives of this study were to evaluate the cerebral collaterals using the mCTA collateral scoring system in AIS patients with large-vessel occlusion (LVO) involving the anterior circulation for determining clinical and radiological outcomes. Materials and Methods: Prospectively, 56 patients with anterior circulation LVO were included in this study; all were subjected to mCTA, and collateral scoring was done. Each patient’s treatment was categorized based on inclusion criteria. The early clinical outcome (National Institutes of Health Stroke Scale [NIHSS] at discharge), late clinical outcome (modified Rankin scale [mRS] at 3-month follow-up), and radiological outcome (Alberta Stroke Program Early CT Score [ASPECTS] and hemorrhagic transformation [HT] at 24 h) were collected. Our primary analysis is intended to the association between collateral score and the clinical outcome. Results: Collateral score is having a statistically significant association (P = 0.0001) with primary functional clinical outcomes (NIHSS at discharge, mRS at 3-month follow-up) and 24 h radiological follow-up (ASPECTS at 24 h; P = 0.0001 and HT at 24 h; P = 0.003). Conclusion: Our study prospectively demonstrates that the mCTA collateral score can be used as a standalone parameter in predicting a better functional outcome of anterior circulation ischemic stroke patients. Further, more inclusive LVO studies are needed in an extended window period (>24 h) and low NIHSS (<6) thrombectomy.