Valve-in-mitral annular calcification (ViMAC) and valve-in-ring (ViRing) transcatheter mitral valve replacements (TMVR) were found to be successful but to frequently require the use of contemporary adjunctive techniques, according to a study published in JACC: Cardiovascular Interventions.

With this retrospective, single-center study, investigators sought to examined in-hospital and 30-day outcomes of off-label ViRing and ViMAC TMVR. Contemporary techniques, including pre-emptive alcohol septal ablation (ASA) and laceration of the anterior mitral valve leaflet to prevent left ventricular outflow tract obstruction (LAMPOON) were used. They assessed in-hospital and 30-day outcomes from September 2015 to April 2020.

A total of 40 patients (median age, 74.2 years; 75% women; Society of Thoracic Surgeons Predicted Risk of Mortality of 7.3%) underwent TMVR (28 with ViMAC and 12 with ViRing).

LAMPOON was performed in 16 patients undergoing ViMAC (57%) and 5 patients undergoing ViRing (42%), and 3 patients underwent preemptive ASA. The median index hospitalization was 7 days.


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Six patients (21%; all in the ViMAC group) died within 30 days of the procedure. In addition, 5 patients (13%) had left ventricular outflow tract obstruction (LVOTO; 14%) in the ViMAC group and 8% in the ViRing group), and 5 patients (13%) had intraprocedural valve embolization or late migration (4 in the ViMAC group and 1 in the ViRing group).

Technical success, defined based on the Mitral Valve Academic Research Consortium criteria, was achieved in 25 patients (63%; 9 in the ViRing group and 16 in the ViMAC group). At 30 days, the mitral valve gradient was reduced compared with pre-TMVR (5.5±2.1 vs 10.6±4.8, respectively; P <.01), and 3 patients (8%) had at least a moderate level of residual mitral regurgitation.

Study limitations include its single center design, small cohort, and short-term follow-up.

“LAMPOON and pre-emptive ASA are frequently used techniques when performing TMVR,” noted the researchers. “With contemporary techniques, LVOTO risk is significantly decreased but not entirely eliminated. When present, LVOTO remains a highly mortal complication. Further refinements in patient selection, procedural technique, and dedicated technology are necessary to continue to address mitral valve disease secondary to mitral annular calcification or a failed annuloplasty ring.”

Reference

Tiwana J, Aldea G, Levin DB, et al. Contemporary transcatheter mitral valve replacement for mitral annular calcification or ring [published online September 27, 2020]. JACC Cardiovasc Interv. doi:10.1016/j.jcin.2020.07.007