Abstract Number ‐ 11: Automated Measurement Of Vascular Tortuosity: Association With Baseline Clinical Characteristics And Impact On Mechanical Thrombectomy
Authors: Canals Pere , Li Jiahui , Balocco Simone , Montesdeoca Oliver Díaz , Tomasello Alejandro , Ribo Marc 
Published: April 2023

Introduction
Vascular tortuosity is considered one of the main hurdles that may negatively impact mechanical thrombectomy in stroke treatment, delaying catheter access to the occluded vessel. Automatic characterization of anatomical vascular features may help in the planification of endovascular interventions. We developed a fully automatic algorithm for vascular tortuosity measurement and explored the association of several anatomical features with baseline characteristics and procedural outcomes.

Methods
An automatic software integrating segmentation, centerline extraction and vessel labelling, was used to extract features directly from computed tomography angiograms (CTA) of stroke patients undergoing transfemoral endovascular treatment.Mean vessel diameter and tortuosity index (TI) of the carotid arteries and brachiocephalic trunk were used as relevant tortuosity indicators. Patients were compared according to six different clinical conditions(gender, hypertension, dyslipidemia, diabetes, obesity and atrial fibrillation). Tortuosity values were also correlated with age.Patients with an anterior circulation stroke were further classified according to four procedural measures:time from groin puncture to first angiographic run, time to first retrieval attempt, time to revascularization.

Results
A sample of 558 patients with acute ischemic stroke who underwent mechanical thrombectomy at our medical center were included in this study. Forty patients (7.2%) were discarded due to sub‐optimal segmentation (n = 30) or processing errors (n = 10), leaving a final sample size of N = 518 (51% female, 74.8±12.9 years). Women presented significantly smaller mean diameter for all analyzed vessels (p < 0.01) and an increased TI for both carotid arteries(p < 0.01). Age was significantly correlated with increased TI in all analyzed vessels (0.35£r£0.52;p < 0.01) Patients with hypertension and/or atrial fibrillation displayed significantly higher TI in both carotid arteries (p < 0.01). Additionally, the brachiocephalic trunk was found to be more tortuous in patients with atrial fibrillation (p < 0.01). A higher TI in all ipsilateral carotid segments was associated with higher times to first angiographic run and to final revascularization (p < 0.05). A TI from the ipsilateral carotid segment over 0.28 independently predicted difficult catheter access (time to first angiographic run >40 min, 3.8% of cases) with a sensitivity of 0.92 and a specificity of 0.68.

Conclusions
An automated software was successfully used to characterize the anatomical vascular features from CTA. Gender, age, hypertension and atrial fibrillation were found to significantly influence vascular tortuosity in anterior circulation arteries. Patients with difficult catheter access and/or delayed revascularization presented higher TI of ipsilateral carotid arteries. Carotid TI emerged as a potential predictor of difficult catheter access.