Haemodynamic Performance of Transcatheter Heart Valve in Bileaflet Mechanical Valve: An In-vitro Study

Objectives This study evaluates the haemodynamic performance of a novel hybrid configuration - Valve-in-MHV - where a CoreValve transcatheter heart valve is implanted within the annulus of a composite valved graft after leaflet removal. Methods In vitro testing was performed using left heart mock loop combined with backlight particle image velocimetry. Three configurations were assessed: (i) mechanical heart valve (MHV), (ii) CoreValve THV, and (iii) Valve-in-MHV. Flow parameters were measured at cardiac outputs of 3 and 5 L/min. Results At 5 L/min, the Valve-in-MHV showed the highest PG (15.5 mmHg) and TKE (0.53 m2/s2), compared to the THV (10.9 mmHg, 0.31 m2/s2) and MHV (11.5 mmHg, 0.26 m2/s2). Effective orifice area was smallest for the Valve-in-MHV (1.44 cm2). The Valve-in-MHV generated a more physiological central jet than the MHV, but with increased turbulence and higher peak velocities (up to 2.66 m/s). Conclusions Examining the mechanistic implications of Valve-in-MHV may offer valuable insights into the likelihood of adverse effects such as leaflet thrombosis and the development of pronounced pressure gradients in patients who are candidates for Valve-in-MHV.