Self-expanding transcatheter aortic valve implantation for degenerated small Mitroflow bioprosthesis: early and midterm outcomes

AIMS: The aim of this study was to report clinical outcomes of self-expanding transcatheter aortic valve implantation (TAVI) for failed small Mitroflow (MF) bioprostheses. METHODS AND RESULTS: Between January 2013 and July 2016, 15 symptomatic patients (NYHA Class ≥III) with degenerated small MF (≤23 mm) underwent CoreValve (CV) or Evolut R (EvR) implantation due to high/prohibitive risk for surgical redo. The MF size was 19 or 21 mm (off-label in Europe) in eight patients. A "preventive" left main (LM) stenting was successfully performed in one patient. Early LM obstruction occurred in two cases requiring stenting. Late LM obstruction was observed in one subject. A significant correlation between virtual left transcatheter valve-to-coronary ostia (VTC) distance and left sinus of Valsalva (LSV) diameter was observed (R=0.652; p=0.012). However, only left VTC was significantly smaller in patients who experienced LM obstruction compared to those who did not (p=0.002). No cases of moderate/severe stenosis were observed in either on- or off-label procedures. No death or other major events occurred up to the one-year follow-up. CONCLUSIONS: CV or EvR implantation for failed small MF has favourable early and midterm outcomes if a careful risk evaluation and preventive measures for coronary obstruction are adopted. Low gradients can be achieved regardless of MF size.