Transcatheter aortic valve implantation for the treatment of degenerated mitroflow bioprosthesis
Authors: Almendarez Lacayo M , Alvarez Velasco R , Hernandez-Vaquero Panizo D , Avanzas Fernandez P , Adeba Garcia A , Vigil-Escalera Diaz M , Moris De La Tassa C , Pascual Calleja I 
Published: November 2020

Abstract

Introduction
The leading cause of valvular heart replacement therapy is symptomatic aortic stenosis (AS). The Mitroflow (MF) bovine pericardial prosthesis is prone to early structural valve deterioration (SVD) and has been used in over 100,000 patients for the treatment of symptomatic AS. The standard of care for degenerated bioprosthesis is surgical aortic valve replacement. However, valve-in-valve transcatheter aortic valve replacement (VIV-TAVI) is an interesting therapeutic modality currently being evaluated to avoid redo surgery.

Purpose
The purpose of this study was to evaluate the clinical outcomes of patients with SVD MF bioprosthesis treated with VIV-TAVI.

Methods
Data was collected from all the patients undergoing TAVI in a single center from March 2012 to July 2019. All the cases remitted for VIV-TAVI were prospectively included and followed. All events were classified according to the VARC-2 definitions. The primary endpoints were a combination of clinical events at the end of the follow-up which included all-cause mortality, cardiovascular mortality, hospitalizations due to heart failure and stroke/transient ischemic attack. Secondary endpoints were absence of SVD and valve hemodynamics at the end of the follow-up.

Results
Between march 2012 and July 2019, 65 patients were derived for VIV-TAVI. The mean age was 80,4±5.93 years. 50,8% were male. The average STS score was 6.39±5,62 and Euroscore II 8.86±5.17. All the patients were diagnosed with SVD with a mixed mechanism (stenosis/regurgitation) being the most frequent form of disfunction (38,5%) followed by regurgitation (33,9%) and stenosis (27,7%).
Procedural success was achieved in 98,5% of the cases, there were 2 deaths of cardiovascular origin, 1 stroke, and 2 hospitalizations due to heart failure. The mean gradient, peak gradient and valve area at discharge were 13,3mmHg, 27,2mmHg and 1,14cm2, respectively.
After 28,8 months (17,4–60,9) of follow-up the combined endpoint occurred in 21 patients (32,3%). There was a total of 13 deaths (20%) and only 4 (7.3%) from cardiovascular causes. 2 patients were reported of having a stroke/TIA and there were 5 readmissions from heart failure (2 of them within the first 30 days).
The mean gradient, peak gradient and valve area remained steady when comparing post-TAVI vs follow-up, 20.3mmHg vs 18.8mmHg (p=0.2), 39.6mmHg vs 35.2mmHg (p=0.01) and 1.3cm2 vs 1.3cm2 (p=0.7), respectively. The same tendency was observed in aortic regurgitation. There were no significant changes in the LVEF over time. There were only 2 patients (3.1%) presenting with valve deterioration during follow-up.

Conclusions
VIV-TAVI for SVD MF bioprosthesis is a safe procedure and a valid alternative to surgery in this group patients, with a high rate of success and low intraprocedural complications. At 28 months of follow-up, 68% of patients were free of late clinical events and valve hemodynamics maintain over time.
Figure 1

Funding Acknowledgement
Type of funding source: None