The Capillary Index Score Trial

Stryker Neurovascular, Rochester General Hospital, University of Vermont Medical Center, University of North Carolina, Chapel Hill, NYU Langone Health, WellStar Health System

This study seeks to investigate the capillary index score (CIS) to further improve patient selection of endovascular treatment (EVT) in acute ischemic stroke (AIS). The hypothesis or idea being tested: Patients with favorable CIS who are successfully revascularized with EVT can have successful outcomes with an extended time window for treatment.

This study is trying to look at how the well-being of the patient following treatment is influenced by peripheral blood supply (collateral flow) to the area lacking primary blood flow due to the clot. Treatment of AIS includes EVT and medical treatment. EVT is typically not offered to patients after 6 hours of the onset of symptoms. The current study is based on the belief that patients can be successfully treated with the EVT up to 8 hours, as long as they have good peripheral blood flow (collateral flow) to the area of tissue blocked of the primary blood supply. The study will evaluate the ability of the capillar index score (CIS) to identify patients who can be successfully treated with EVT. The CIS quantifies blood supply to the ischemic area from peripheral vessels (collateral flow) based on diagnostic cerebral angiogram. Patients are graded on a scale from 0-3, with 0 and 1 considered a poor CIS (pCIS) and 2 and 3 considered a favorable CIS (fCIS). All patients will be treated with EVT and medical treatment consistent with national guidelines. The primary endpoint is the clinical outcome at 90 days between fCIS group versus pCIS group. The secondary endpoint is the influence of successful revascularization on outcomes for patients with fCIS or pCIS.

capillary index score, acute ischemic stroke, collateral circulation, cerebral ischemia, diagnostic imaging

Patients will be assigned to one of two groups based on the outcome of diagnostic evaluation. Treatment will be identical for the two groups.

Patients with a favorable CIS (fCIS) will receive endovascular treatment (EVT) and medical treatment consistent with national guidelines.

Patients with a poor CIS (pCIS) will receive endovascular treatment (EVT) and medical treatment consistent with national guidelines.

EVT is an endovascular procedure in which a catheter is inserted into an artery and directed to the site of the blocked blood vessel in the brain. The clot is removed using a mechanical device with or without an injection of tPA (tissue plasminogen activator) directly at the site of the clot. The protocol calls for use of the Trevo stent retriever (Stryker Neurovascular) for the first pass of clot removal.

The mRS Score ranges from 0-6 and describes the degree of disability or dependence after a stroke. The grades are no symptoms (0), no significant disability (1), slight disability (2), moderate disability (3), moderately severe disability (4), severe disability (5), and death (6).

Complication : Clinically relevant intracranial hemorrhage and vasogenic edema as defined by parenchymal hematoma (PH) 1 or 2

Modified Rankin Score (mRS) Between Favorable CIS With Good Revascularization Versus Poor CIS With Good Revascularization.

Revascularization status will be classified as poor (mTICI = 0-2A) or good (mTICI = 2B, 3). Rate of good clinical outcomes between groups will be compared based on the combination of CIS and revascularization status. Good outcome will be measured based on the modified Rankin scale score according to: 0: No symptoms No significant disability despite symptoms Slight disability Moderate disability Moderately severe disability Severe disability Dead A score of 0-2 is considered a good outcome

Inclusion Criteria: Anterior circulation acute ischemic stroke due to blockage of the intracranial internal carotid artery or middle cerebral artery (M1) Within 24 hours of onset of symptoms NIHSS Score is 8 or greater Exclusion Criteria: Contra-indication for IAT found on initial CT Intracranial hemorrhage Stroke mimics (tumor, herpetic encephalitis, etc.) More than 1/3 hypodensity on non-enhanced head CT prior to intervention ASPECT Score less than 6 Pre-existing disability defined as modified Rankin Scale (mRS) score more than 2 Pregnant women

Al-Ali F, Elias JJ, Filipkowski DE, Faber JE. Acute ischemic stroke treatment, part 1: patient selection "the 50% barrier and the capillary index score". Front Neurol. 2015 Apr 22;6:83. doi: 10.3389/fneur.2015.00083. eCollection 2015.

Al-Ali F, Elias JJ, Filipkowski DE. Acute Ischemic Stroke Treatment, Part 2: Treatment "Roles of Capillary Index Score, Revascularization and Time". Front Neurol. 2015 Jun 1;6:117. doi: 10.3389/fneur.2015.00117. eCollection 2015.

Al-Ali F, Elias JJ, Tomsick TA, Liebeskind DS, Broderick JP; IMS Study Groups. Relative Influence of Capillary Index Score, Revascularization, and Time on Stroke Outcomes From the Interventional Management of Stroke III Trial. Stroke. 2015 Jun;46(6):1590-4. doi: 10.1161/STROKEAHA.115.009066. Epub 2015 May 7.

Al-Ali F, Tomsick TA, Connors JJ 3rd, Gebel JM, Elias JJ, Markarian GZ, Al-Ali Z, Broderick JP. Capillary Index Score in the Interventional Management of Stroke trials I and II. Stroke. 2014 Jul;45(7):1999-2003. doi: 10.1161/STROKEAHA.114.005304. Epub 2014 May 22.

Al-Ali F, Jefferson A, Barrow T, Cree T, Louis S, Luke K, Major K, Nemeth D, Smoker S, Walker S. The capillary index score: rethinking the acute ischemic stroke treatment algorithm. Results from the Borgess Medical Center Acute Ischemic Stroke Registry. J Neurointerv Surg. 2013 Mar;5(2):139-43. doi: 10.1136/neurintsurg-2011-010146. Epub 2012 Jan 19.