Introduction: Rapid assessment of collateral status is an important issue for therapeutic decision making in acute ischemic stroke(AIS), because collaterals may affect revascularization, ischemic severity and clinical outcomes. CT angiography(CTA) is non-invasive and more feasible as a fast diagnostic tool than conventional angiography, therefore it was commonly used as the initial evaluation tool in AIS.
Hypothesis: To examine correlation between collateral status observed by CTA and clinical outcomes in patients with acute ICA occlusion.
Methods: The patients with ICA occlusion who underwent CTA within 6h of symptom onset were collected retrospectively. We assessed collateral status using CTA and evaluate correlation between collateral grades and clinical outcome. Collateral grades were classified as grade 1-4(Figure1). Clinical outcome was measured by major neurologic improvement(MNI) and good functional outcome. MNI was defined by a ≥8 point improvement in NIH Stroke Scale and good functional outcome was defined as modified Rankin scale at 90 days of 0 to 2.
Results: A total of 50 patients were included in this study. In analysis of CTA collateral, 13 patients were classified as grade1, 8 patients as grade2, 9 patients as grade3, and 20 patients as grade4, respectively. In grade 1 patients, there were no patients who showed MNI or good outcome. In contrast, among grade 4 patients, 3 patients(15%) showed MNI and 10 patients(50%) had good functional outcome. Especially, patients in group 4 with successful recanalization demonstrated favorable outcome (2 of 10 MNI, 8 of 10 good functional outcome). In grade2 and 3 patients, the proportion of MNI and good functional outcome was between that of grade1 and 4 patients (grade2: no MNI, good functional outcome 2 of 12, grade 3: MNI 2 of 9, good functional outcome 1 of 9).
Conclusions: Collateral flow status assessed by CTA can predict clinical outcomes in AIS, and further studies are needed to verify this correlation.