TMVR in Severe Mitral Annular Calcification

Transcatheter mitral valve replacement (TMVR) with balloon-expandable valves is feasible in patients with severe mitral annular calcification, according to a multicenter retrospective review published in JACC: Cardiovascular Interventions.

Mayra Guerrero, MD, director of cardiac structural interventions at Evanston Hospital/NorthShore University Health System in Evanston, Illinois, and colleagues evaluated outcomes in early experiences of TMVR. As they explained, “Patients with mitral annular calcification are an elderly high-risk patient population with multiple comorbidities even before they develop valvular dysfunction. They have a higher risk of cardiovascular disease, cardiovascular death, and all-cause mortality.”

Dr Guerrero and colleagues selected 64 patients (mean age: 73 ± 13 years; 66% female) who underwent TMVR from 32 centers in Mitral Annular Calcification Global Registry. To be included in the study, patients had to have symptomatic mitral valvular disease with severe mitral annular calcification and be ineligible for standard mitral valve surgery due to comorbidities or “technical reasons related to calcium burden.”

Of the 64 patients, 34 had a prior aortic valve replacement either with a transcatheter heart valve (Edwards Lifesciences SAPIEN or Medtronic CoreValve) or surgical aortic valves (mechanical or bioprosthetic). Left ventricular ejection fraction was preserved in most patients (59.5% ± 11.3%), the primary mitral valve pathology was stenosis in 93.5%, and 6.5% had mostly mitral regurgitation.

Technical success was achieved in 46 patients, according to Mitral Valve Academic Research Consortium criteria. Eleven patients required a second valve and 6 patients had left ventricular tract obstruction with hemodynamic compromise. Post-procedure the mean mitral gradient was 4 mm Hg ± 2.2 mm Hg and paravalvular regurgitation was minimal or absent.

The mean follow-up was 4 months in which periprocedural death occurred in 29.7% patients—12.5% due to a cardiovascular cause and 17.2% due to a noncardiac cause. In 84% of survivors, the New York Heart Association functional class was either at class I or II at 30 days (n=25).

“Although there were important complications and a high 30-day mortality, these results are encouraging considering this represents the first human experience with a THV [transcatheter heart valve] not designed for the mitral position and used in an extremely high-risk patient population with a mean Society of Thoracic Surgeons risk score higher than in the PARNTER I (Placement of Aortic Transcatheter Valves) trial,” researchers noted.

They also acknowledged that the learning curve for this procedure in patients with severe mitral annular calcification has been very steep, and that there were many unknowns throughout the initial stages of the registry.

While the study has significant limitations—mainly related to small size and lack of homogeneity—researchers seemed encouraged. They wrote that the ongoing MITRAL (Mitral Implantation of Transcatheter Valves) clinical trial may offer further insights to improve technical success, patient selection, and overall clinical outcomes.

Disclosures: Dr Guerrero has served as a proctor and consultant for and received research grant support from Edwards Lifesciences. Drs Dvir and Himbert have also served as consultants to Edwards Lifesciences. 

Reference

Guerrero M, Dvir D, Himbert D, et al. Transcatheter mitral valve replacement in native mitral valve disease with severe mitral annular calcification. Results from the first multicenter global registry. JACC Cardiovasc Interv. 2016;9(13):1361-1371. doi:10.1016/j.jcin.2016.04.22.