More than One Consecutive TAVI Valve-in-valve after Conventional Aortic Valve Replacement: How Often Can we do It?

Objective: Endovascular valve implantation (TAVI) in degenerated stented biological valves (ViV) has become clinical routine. As a consequence, more and more younger patients with aortic valve disease decide toward a bioprosthesis with the option for TAVI ViV after degeneration. Thus, as the average degeneration time for a bioprosthesis is ~10 years these patients require more than one TAVI ViV over their life span. The question is, how often we can do it? Systematic studies about the hemodynamic performance of multiple TAVI ViV in stented bioprosthesis, however, do not exist.

Methods: Stented biological valves of 23mm size were analyzed in a pulse duplicator (cardiac output 4.9 L/min). Edwards Perimount Magna (EP), SJM Triflecta (ST), Sorin Mitroflow (SM) and Medtronic Mosaic (MM) were investigated (Three valves, each type). Mean transvalvular gradients (TVG) and Hegar stick diameter were measured before and after implantation of first, second, and third ViV with Edwards Sapien (SAPIEN) valve.

Results: There were no marked differences of mean transvalvular gradients before ViV. TVG increased after every VIV-procedure while valves fabricated from porcine cusps showed higher gradients in contrast to valves constructed with pericardium (Table 1). Every ViV-procedure reduced the inner diameter ~2 mm.

Conclusion: This in vitro study shows good hemodynamic performance of endovascular valves as first ViV in 23 mm stented bioprosthesis being currently the most often implanted size. For this particular size the hemodynamic function becomes critical after the third procedure in pericardial valves and already after the second procedure in porcine cusp valves probably owing to the smaller inner-outer diameter ratio of these valves. The surgeon may thus decide toward a pericardial valve up to 23 mm valve size to maintain the option for at least 2 consecutive ViV.

Table 1 Mean TVG of different stented biological valves

TVG	EP 23mm	ST 23mm	SM 23mm	MM 23mm
Pre ViV	5.6 mm Hg	4.4 mm Hg	6.5 mm Hg	8.3 mm Hg
ViV1 (SAPIEN 23mm)	9.8 mm Hg	7.6 mm Hg	11.9 mm Hg	14.1 mm Hg
ViV2 (SAPIEN 20mm)	14.4 mm Hg	13.9 mm Hg	18.2 mm Hg	23.2 mm Hg
ViV3 (SAPIEN 20mm)	27.1 mm Hg	25.2 mm Hg	31.4 mm Hg	36.6 mm Hg

No conflict of interest has been declared by the author(s).