In-Vitro Hydrodynamic Testing of Valve-in-Valve Procedures in Surgical Bioprosthetic Valves with Small Annuli

Background: It is well known that valve-in-valve (ViV) aortic procedures, especially in small bioprotheses, result in higher transvalvular gradients. However, it remains unclear how these gradients alter with increasing cardiac output under stress. This in-vitro study aimed to assess the hydrodynamic performance of balloon-expandable and self-expandable transcatheter heart valves (THV) after ViV implantation in small surgical heart valves (SHV) under physiological stress.

Methods: ViV implantation of a 20-mm SAPIEN 3 Ultra, a 23-mm Evolut Pro, and a 23-mm Allegra THV was conducted in a 19-mm Perimount and a 21-mm Trifecta SHV. Implantation height, commissural alignment, and complete valve expansion were ensured by X-ray and micro-CT before integration into the pulse duplicator. Transvalvular pressure gradients (TPG), geometric and effective orifice areas (GOA, EOA), and valvular leakage volumes were assessed under pulsatile conditions with increasing stroke volume (SV) up to 100 mL (cardiac output 3.5 to 6.5 L/min) and confirmed in a steady forward flow-tester.

Results: Self-expandable supra-annular ViV implantation was associated with lower TPG, lower leakage volumes, and greater GOA and EOA compared with balloon-expandable THV. This difference was particularly evident at high cardiac output, as there was an exponential increase in the gradients with increasing SV. Mean TPGs for the various ViV combinations at SV 100 mL are shown in the [Table 1]. Allegra implantation tended to show the most favorable hydrodynamic performance (p > 0.05 compared with Evolut). Moreover, ViV implantation of SAPIEN 3 showed high valvular leakage (Perimount SAPIEN 3: 8.4 ± 0.17% and Trifecta SAPIEN 3: 10.2 ± 0.14% of SV) due to incomplete expansion, which was confirmed by micro-CT.

Table 1 Mean TPGs for ViV combinations

	TPG mean [mmHg]		TPG mean [mmHg]
Perimount SAPIEN 3	20 ± 0.2	Trifecta SAPIEN 3	15 ± 0.4
Perimount EVL Pro	16.9 ± 0.2	Trifecta EVL Pro	13.0 ± 0.3
Perimount Allegra	15.0 ± 0.4	Trifecta Allegra	11.9 ± 0.25

Conclusion: This study shows favorable hydrodynamic profiles at rest and under stress for supra-annular TVH compared with intra-annular THV as a ViV implant in SHV with small annuli. Due to the high gradients assessed under physiological stress, surgical reintervention should also be taken into consideration for small SHV.

Publication History

Article published online:
11 February 2025