Arch and Great Vessel Geometry From a Transradial Angiographic Approach

Neuroendovascular practices are transitioning from transfemoral to a radial-first approach for cerebral angiography. Developing radial-specific devices requires a comprehensive understanding of vessel size and geometry encountered from a right radial approach. We developed a database of aortic arch and vessel measurements relevant for radial-specific device development.

The database contained 100 consecutive neck computed tomographic angiograms conducted on a 256-slice emergency department computed tomographic scanner. Arch characteristics and measurements obtained from 1-cm maximum intensity projection reformats included arch type and diameter, bifurcation angles, and distances from the arch to vessel origins. Statistical analysis was conducted using Excel and R.

The database contained 56 female and 44 male patients; the average age was 62 years. A total of 46% had type 2 or 3 arch configuration, 19% had bovine configuration, and 5% had a left vertebral artery originating directly from the arch. Median angles at the arch from the innominate ranged from 20° to 47° and at branch vessels from 16° to 63° with large variation. The left carotid bifurcation was ≈8 cm further than the right carotid bifurcation. The left vertebral artery origin was median 3.8 cm from the arch.

We cataloged aortic arch and vessel geometries that have implications for catheter and device performance from a transradial approach. For example, a standard guide catheter that is adequate length for the right anterior circulation must be at least 8 cm longer for comparable distal support on the left because of the difference in distance from the right to the left. Catheter tip shape may be further optimized to improve vessel selection. Currently used catheters make a reverse curve angle of ≈15°, although most great vessels are at between 15° and 45°. Finally, the length of the distal arm of reverse curve catheters is just >4 cm, frequently inadequate to easily reach the left vertebral artery origin (median distance, 3.8 cm in this study). Transradial devices should be developed with these constraints in mind. This database provides benchmarks for future catheter design.