Who Lives Longer, the Valve or the Patient? The Dilemma of TAVI Durability and How to Optimize Patient Outcomes

Abstract

Over the past few years, transcatheter aortic valve implantation (TAVI) imposed itself as the first-choice therapy for symptomatic aortic stenosis (AS) in elderly patients at surgical risk. There have been continuous technological advancements in the latest iterations of TAVI devices and implantation techniques, which have bolstered their adoption. Moreover, the favorable outcomes coming out from clinical trials represent an indisputable point of strength for TAVI. As indications for transcatheter therapies now include a low surgical risk and younger individuals, new challenges are emerging. In this context, the matter of prosthesis durability is noteworthy. Initial evidence is beginning to emerge from the studies in the field, but they are still limited and compromised by multiple biases. Additionally, the physiopathological mechanisms behind the valve's deterioration are nowadays somewhat clearer and classified. So, who outlasts who-the valve or the patient? This review aims to explore the available evidence surrounding this intriguing question, examining the various factors affecting prosthesis durability and discussing its potential implications for clinical management and current interventional practice.

Keywords: aortic stenosis (AS); bioprosthetic valve failure (BVF); durability; structural valve degeneration (SVD); transcatheter aortic valve implantation (TAVI).

Figure 1

The four categories of bioprosthetic valve dysfunction. (A): Structural valve deterioration is a deterioration process that directly involves the valvular components leading to prosthesis stenosis or regurgitation (e.g., fibrotic degeneration, leaflet tear). (B): Non-structural valve dysfunction (NSVD) (e.g., para-prosthetic regurgitation). (C): Thrombosis. (D): Endocarditis. Parallel to the BVD pathological categories, three stages of dysfunction, based mainly on the mean gradient (MG), the effective orifice area (EOA), the Doppler velocity index (DVI), and intraprosthetic aortic regurgitation (AR), have been proposed (table one).

Figure 2

The triangle of factors influencing valve durability.

Figure 3

Diagnosis flowchart in case of suspicion of bioprosthesis valve dysfunction. BVD: bioprosthesis valve dysfunction; MSCT: multi-slice computed tomography; TEE: trans-esophageal echocardiography; TTE: trans-thoracic echocardiography; [18F]-FDG-PET: [18]-fluorodeoxyglucose-positron emission tomography. *: nuclear imaging may be applicable in case of high clinical suspicion of endocarditis with inconclusive TTE/TEE.