Validating a Curvature‐Based Marker of Cervical Carotid Tortuosity for Risk Assessment in Heritable Aortopathies

Abstract

Background Cervical arterial tortuosity is associated with adverse outcomes in Loeys‐Dietz syndrome and other heritable aortopathies. Methods and Results A method to assess tortuosity based on curvature of the vessel centerline in 3‐dimensional space was developed. We measured cervical carotid tortuosity in 65 patients with Loeys‐Dietz syndrome from baseline computed tomography angiogram/magnetic resonance angiogram and all serial images during follow‐up. Relations between baseline carotid tortuosity, age, aortic root diameter, and its change over time were compared. Patients with unoperated aortic roots were assessed for clinical end point (type A aortic dissection or aortic root surgery during 4 years of follow‐up). Logistic regression was performed to assess the likelihood of clinical end point according to baseline carotid tortuosity. Total absolute curvature at baseline was 11.13±5.76 and was relatively unchanged at 8 to 10 years (fold change: 0.026±0.298, P =1.00), whereas tortuosity index at baseline was 0.262±0.131, with greater variability at 8 to 10 years (fold change: 0.302±0.656, P =0.818). Baseline total absolute curvature correlated with aortic root diameter ( r =0.456, P =0.004) and was independently associated with aortic events during the 4‐year follow‐up (adjusted odds ratio [OR], 2.64 [95% CI, 1.02–6.85]). Baseline tortuosity index correlated with age ( r =0.532, P <0.001) and was not associated with events (adjusted OR, 1.88 [95% CI, 0.79–4.51]). Finally, baseline total absolute curvature had good discrimination of 4‐year outcomes (area under the curve=0.724, P =0.014), which may be prognostic or predictive. Conclusions Here we introduce cervical carotid tortuosity as a promising quantitative biomarker with validated, standardized characteristics. Specifically, we recommend the adoption of a curvature‐based measure, total absolute curvature, for early detection or monitoring of disease progression in Loeys‐Dietz syndrome.