Assessment Of Collateral Pathways In Acute Ischemic Cerebrovascular Stroke Using A Mansour Grading Scale; A New Scale, A Pilot Study

摘要

Objective:The purpose of this study was to assess collateral pathways in acute ischemic stroke using a new grading scale (Mansour Scale) and correlating the findings with different risk factors, clinical outcome and recanalization rate with endovascular management.Cerebral collateral circulation is an indirect pathway for restoration of blood flow to ischemic areas in case of obstruction of their primary blood supply. Assessment of cerebral collaterals is of utmost importance in the setting of acute stroke as it carries diagnostic, therapeutic and prognostic values. Our study aimed at assessing collaterals in acute ischemic stroke using a new grading scale (Mansour Scale) developed in our department and correlating the angiographic findings with different stroke risk factors and with clinical outcome. The new scale assesses collaterals regarding their type, pattern, site of occlusion, robustness and functionality and outcome is assessed using NIHSS scale.Conclusion:We concluded that better collateralization by our new scale is associated with better recanalization and better clinical outcome. We found no effect of different stroke risk factors studied on collateral development. Introduction The cerebral collateral circulation refers to the subsidiary network of vascular channels that stabilize cerebral blood flow when principal conduits fail. Restriction of the blood flow is the major cause of recruitment of these collaterals in acute ischemic stroke. Effective perfusion to the ischemic area results from the net balance between residual anterograde flow across the obstructive lesion and the flow through collateral routes—often using retrograde flow via auxiliary vessels (1).Three principal pathways constitute cerebral collaterals; Circle of Willis, Leptomeningeal Collaterals and Extracranial-Intracranial anastmosis. Several techniques can provide insight into collateral flow in patients with ischemic stroke using different imaging modalities, but conventional angiography is superior in many aspects regarding spatial and temporal resolution and is the only modality that illustrates retrograde leptomeningeal collateral flow reliably and in detailed fashion (2).In the literature, there are over eighty publications describing 63 methods for grading collateral flow on the basis of conventional angiography. However, these methods measure the general status of collaterals and not actual anatomical connections and most of them are unvalidated and contain many flaws. The need for a reliable grading scale for proper assessment of collaterals is mandatory. In this study we aimed at assessing collateral pathway in acute stroke using a newly invented classification/ grading scale (Mansour Scale) and correlating the findings with different risk factors, recanalization and clinical outcome (3). Subjects and Methods We conducted a prospective study that enrolled 30 patients with acute ischemic insults (stroke or transient ischemic attacks) with different neurological symptoms, severity and risk factors who presented to different stroke centers in Alexandria and Tanta. All our patients underwent a complete history taking, thorough general and neurological examination, assessment of severity using National Institutes of Health Stroke Scale (NIHSS) scale, routine laboratory investigations and different neuroimaging modalities( CT or MRI). An informed consent was taken from all patients.All our patients underwent catheter angiography either as a primary endovascular intervention for recanalization (IA-rtPA injection or mechanical thrombectomy) or as a secondary preventive measure (angioplasty or stenting). Collateral status was assessed according to a Mansour Scale (Appendix) and a grading score was given to each type of collaterals according to the next table (Table 1). Collaterals were correlated with different risk factors, recanalization rate and clinical outcome. Our new grading scale assessed collaterals regarding their type, pattern, site