A Novel Computed Tomographic Angiography Tortuosity Index to Predict Successful Sentinel Cerebral Embolic Protection Delivery for Transcatheter Aortic Valve Replacement.

Background: Percutaneous transradial placement of the Sentinel cerebral embolic protection device (CEPD) (Boston Scientific) is indicated during transcatheter aortic valve replacement to capture embolic material in patients without excessive tortuosity of the right subclavian/innominate arteries. We aimed to generate a quantitative tortuosity index (TI) from the preoperative computed tomographic angiography (CTA) as an objective measure of tortuosity to determine suitability for CEPD placement. Methods: Eighty-one patients considered for CEPD were included in this study. A centerline of the right subclavian/innominate arteries was generated from preoperative CTA scans. Three-dimensional Cartesian coordinates of landmarks along the centerline were used to calculate curvature. Tortuosity was derived as a change in angulation along each vessel segment. Peak and average TI values were calculated. Results: Sixty-seven patients had CEPD placement attempted. Unsuccessful CEPD placement occurred in 3 of 67 (4.4%) patients. The peak tortuosity for the successful, unsuccessful, and visually tortuous (not attempted) cohorts were 49.66 ± 11.96°/cm, 113.92 ± 5.70°/cm, and 70.44 ± 17.01°/cm, respectively. The peak and average TI of the successful cohort follows a normal distribution. A proposed TI cutoff for safe CEPD was peak tortuosity of 74°/cm and average tortuosity of 30°/cm, 2 standard deviations above the peak and average TI of the successful cohort. All unsuccessful CEPD patients fell outside the boundaries. Half of the visually tortuous patients were within the boundaries but did not have CEPD attempted. Conclusions: A novel TI based on preoperative CTA can assist in selecting patients for transradial CEPD. Our proposed quantitative tool may help to appropriately include and exclude patients for CEPD placement.