Capillary Index Score and Correlation with Outcomes in Acute Ischemic Stroke: a Meta-analysis

Abstract

Background and Purpose—The capillary index score (CIS) has been recently introduced as a metric
for rating the collateral circulation of ischemic stroke patients. Multiple studies in the last five years have
evaluated the correlation of good CIS with clinical outcomes and suggested the use of CIS in selecting
patients for endovascular treatment. We performed a meta-analysis of these studies comparing CIS with
clinical outcomes.
Methods—We conducted a computerized search of three databases from January 2011 to November 2015
for studies related to CIS and outcomes. A CIS = 0 or 1 is considered poor (pCIS) and a CIS = 2 or 3 is
considered favorable (fCIS). Using random-effect meta-analysis, we evaluated the relationship of CIS to
neurological outcome (modified Rankin scale score ≤ 2), recanalization, and post-treatment hemorrhage.
Meta-regression analysis of good neurological outcome was performed for adjusting baseline National
Institutes of Health Stroke Scale (NIHSS) between groups.
Results—Six studies totaling 338 patients (212 with fCISs and 126 with pCISs) were included in the analysis. Patients with fCIS had higher likelihood of good neurological outcome [relative risk (RR) = 3.03; confidence interval (CI) = 95%, 2.05–4.47; p < 0.001] and lower risk of post-treatment hemorrhage (RR =
0.38; CI = 95%, 0.19–0.93; p = 0.04) as compared with patients in the pCIS group. When adjusting for
baseline NIHSS, patients with fCIS had higher RR of good neurological outcome when compared with
those with pCIS (RR = 2.94; CI = 95%, 1.23–7, p < 0.0001). Favorable CIS was not associated with higher
rates of recanalization.
Conclusions—Observational evidence suggests that acute ischemic stroke patients with fCIS may have
higher rates of good neurological outcomes compared with patients with pCIS, independent of baseline
NIHSS