Development of four different devices to turn over introducer sheaths

We developed four prototype sheath-turning auxiliary devices (STADs) and evaluated them in an in vitro study setup designed to enable the change of catheter direction in endovascular interventions.

Four different prototypes, A through D, of STADs were designed and created by modifying commercially available dilators and catheters. All STADs work with different anchor-like tips to ensure fixation inside the vessel at the puncture site. The STAD is loaded into the introducer sheath, retracted with the introducer sheath, and turned at the puncture site. The STADs were tested in an in vitro vascular study setup using bovine veins. Success rates and procedure times were calculated, and the handling, reliability, and overall performance were evaluated. The maximum soft tissue thickness (STTmax) applicable was tested using bovine vessels with 7-mm thickness surrounded by a soft tissue phantom consisting of chicken breast. A retrospective cross-sectional observation in 108 patients from our center was performed to provide mean STTmax at the common femoral artery in patients for comparison.

The success rate ranged between 75% for prototype D and 90% for prototypes A and C. The procedure time averaged 60 seconds (range, 25-165 seconds). The mean handling was rated 2.4 (good) for prototype A, 2.0 (good) for prototype B, 2.6 (satisfactory) for prototype C, and 3.5 (poor) for prototype D. Mean reliability was rated 3.4 (satisfactory) for prototype A, 2.0 (good) for prototype B, 1.6 (good) for prototype C, and 2.4 (good) for prototype D. Mean overall performance was rated 2.0 (good) for prototype C, 2.6 (satisfactory) for prototype B, 3.3 (poor) for prototype D, and 3.4 (poor) for prototype A. In the cross-sectional patient observation, the mean STTmax was 3.3 cm (range, 0,5-13 cm) with a 95% confidence interval of the distribution including an STTmax of up to 8 cm. The STTmax was ≤ 5 cm in 100 of 108 patients (93%). The applicable STTmax for prototype A was 1 cm (8 of 10 successful cases), 3 cm for prototype B (9 of 10 successful cases), 5 cm for prototype C (8 of 10 successful cases), and 3 cm for prototype D (7 of 10 successful cases).

All four STAD prototypes offered the ability of turning the sheaths at the puncture site in an in vitro vascular study setup. In the future, this concept may allow routine clinical performance of turning maneuvers at the groin vascular access site.