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Incidence and mechanisms of bioprosthetic dysfunction after transcatheter implantation of a mechanically-expandable heart valve.

BACKGROUND
The mechanically-expandable transcatheter valve is no longer commercially available, yet clinical and echocardiographic surveillance is imperative for thousands of patients who received transcatheter aortic valve implantation (TAVI) with this platform.


AIMS
We aimed to determine the incidence and mechanism of bioprosthetic valve dysfunction (BVD) following TAVI with mechanically-expandable valves.


METHODS
From 2013 to 2020, all 234 patients who underwent TAVI with the LOTUS valve were included. BVD was categorised as (i) structural valve deterioration (SVD), (ii) non-structural valve dysfunction (NSVD), (iii) clinical valve thrombosis and (iv) endocarditis, according to the Valve Academic Research Consortium-3 criteria.


RESULTS
The mean age was 79±7 years, 60% were male, and the mean Society of Thoracic Surgeons score was 4.2±2.9%. The technical success rate was 94% and the 30-day device success rate was 78%. All-cause mortality at 1 year was 15%; median follow-up duration was 36 (IQR 18-60) months during which 47% of patients died. One hundred and three patients had ≥1 type of BVD (44%), which predominantly consisted of NSVD (39%, mostly because of ≥moderate patient-prosthesis mismatch). BVD during follow-up included endocarditis (3.4%), clinical valve thrombosis (3.4%) and SVD (1.3%). Both endocarditis and clinically apparent valve thrombosis occurred early and late after TAVI and resulted in valve-related deaths in 38% and 13% of patients, respectively. Overall, ≥moderate haemodynamic valve deterioration occurred in 5.5% and bioprosthetic failure in 7.3%, leading to valve-related deaths in 36% of cases.


CONCLUSIONS
BVD represents a relevant health issue after TAVI with a mechanically-expandable valve. Serious but reversible causes of BVD include endocarditis and clinically apparent valve thrombosis, both carrying a time-independent hazard post-TAVI.