The Verification of Co‐Axiality of the Three Self‐Expanding Transcatheter Aortic Valve Systems According to the Difference in Shaft Spine

BACKGROUND: Accurate bioprosthesis implantation depth during transcatheter aortic valve replacement (TAVR) is crucial for optimal outcomes. Self-expanding valves (SEVs) have evolved delivery catheter designs, from a double spine shaft in Evolut PRO+ (PRO + ) to single spine in Evolut FX (FX) and non-spine in Navitor, to improve access deliverability. AIMS: To investigate the influence of different spine structures on valve implantation. METHODS: Retrospectively, we investigated 95 severe aortic stenosis patients who underwent transfemoral TAVR using SEVs (PRO + : 41, FX: 21, and Navitor: 33 patients) from January 2021 to July 2023. The implantation depth difference (IDD) between Left Coronary Cusp (LCC) and Non-Coronary Cusp (NCC) was measured angiographically at the point of no recapture, defined as subtracting NCC implantation depth from LCC. Positive IDD indicates deeper LCC than NCC, also shown as "vertical axis." Whereas negative IDD indicates shallower LCC than NCC, demonstrated as "horizontal axis." RESULTS: IDD at the point of no recapture showed significant difference among three groups (PRO + : 2.42 [0.81-3.42], FX: 1.01 [0.29-1.77], Navitor: -2.16[-2.74- (-1.14)] mm, p < 0.001, PRO + > FX/Navitor, FX > Navitor). PRO+ had a positive IDD, indicating deeper LCC implantation. Navitor had a negative IDD, demonstrating shallower implantation on LCC, and FX showed co-axial implantation. CONCLUSION: PRO+ with double spines showed vertical axis, Navitor with non-spine showed horizontal axis, whereas FX demonstrated co-axiality at the point of no recapture. This knowledge may help refine the manipulation of procedural implantation based on the shaft rigidity in each device to gain co-axiality.