Valve-in-ring (ViR) implantation is a reasonable alternative for patients at high surgical risk, said researchers presenting on the MITRAL study at Transcatheter Cardiovascular Therapeutics (TCT 2017) meeting. With improved patient selection and techniques, native valve (ViMAC) procedures could also be a reasonable alternative. In both cases, compared with data from registries ViR and ViMAC procedures have improved overall.

The MITRAL study enrolled and treated 90 patients at extremely high surgical risk (STS PROM >15% or M&M >50%). Of these, 30 patients with severe mitral stenosis (MS) or severe mitral regurgitation (MR) and moderate MS underwent ViMAC and 30 patients with severe MS and at least moderate to severe MR underwent ViR. (Another 30 patients with severe MS and at least moderate to severe MR underwent valve-in-valve (MViV) implantation, the results of which will be presented later in November at AHA 2017 in Anaheim.) Primary endpoints included technical success at exit from the catheterization lab/operating room, procedural success at 30 days, and patient success at one year. Secondary safety and effectiveness endpoints included a composite of various adverse events at 30 days and one year.

Researchers noted several findings from the study, including a preference for transseptal access for all ViR procedures and selected ViMAC patients when anatomy is favorable. They also highlighted that transseptal ViR was achieved in 100% of patients in this cohort and that it was associated with low 30-day mortality (6.8%), a low complication rate and significant improvement in symptoms.

ViMAC, on the other hand, remains challenging, researchers said. Transcatheter mitral valve replacement (TMVR) in MAC was associated with complications, including left ventricular outflow tract obstruction with hemodynamic compromise and need for a new pacemaker. The 30-day mortality rate was 19.2%. However, they noted that techniques such as pre-emptive alcohol septal ablation, use of cardiac CT analysis to improve patient selection and outcomes, and even valve design changes, could improve patient outcomes.