The role of carotid elongation for intervention time and outcome in mechanical thrombectomy for anterior circulation acute ischemic stroke.

Introduction: This study investigates the influence of carotid artery elongation on neurovascular intervention and outcome in acute stroke treatments proposing an easily assessable imaging marker for carotid elongation.

Methods: 118 patients who underwent mechanical thrombectomy for middle cerebral artery occlusions were included. The carotid elongation ratio (CER), center-line artery length to scan's Z-axis, was measured on the affected side in CT-angiographies. Full and partial correlations of CER with periprocedural times, complications and outcome were computed. Multivariate logistic regression, including comorbidities, for prediction of dichotomized mRS outcome after 3 months was performed.

Results: CER showed no significant correlation with recanalization success. Weak, outlier-driven correlation was found with recanalization time (p = 0.021, cor = 0.2). Weak correlations were found with improvement of NIHSS score at discharge and mRS score after 3 months (p = 0.023 and p = 0.031, each rho=-0.2). There was moderate correlation with NIHSS score at discharge (p = 0.001, rho = 0.3). Patients with favorable outcomes (mRS 0-2) exhibited lower CER (p = 0.012). Partial correlations of CER with favorable outcomes were observed after correcting for age, sex and cardiovascular risk factors (cor = 0.2, p = 0.048). Multivariate analysis (Nagelkerke's R2 = 0.42) identified NIHSS score at admission, diabetes, hypertension and intervention time as significant factors for predicting outcome at 3 month, while CER showed the highest log Odd's (2.97).

Conclusion: Correlations between CER and clinical improvement suggest that carotid elongation might be a risk factor for poorer outcome without relevant effect on endovascular treatment and should not guide treatment decisions. Further studies should consider carotid elongation as an individual neurovascular risk factor, independent of hypertension.