Transcatheter Mitral Valve Replacement With Atrial Fixation for Treatment of Atrial Functional Mitral Regurgitation.

Background: Many patients with atrial functional mitral regurgitation are not suitable candidates for surgery or transcatheter repair. For transcatheter mitral valve replacement, a common contraindication is the risk of left ventricular outflow tract obstruction, particularly in patients with atrial functional mitral regurgitation, who have characteristically small left ventricles. Herein, we examine the outcomes of transcatheter mitral valve replacement using the AltaValve system, which employs atrial fixation thus minimizing left ventricular outflow tract obstruction risk.

Methods: Patients with severe, symptomatic mitral regurgitation who were treated in the AltaValve early feasibility study or on the basis of a compassionate use exemption. The definition of atrial functional mitral regurgitation required the presence of: (1) severe mitral regurgitation; (2) atrial fibrillation; (3) normal left ventricular size; (4) left ventricular ejection fraction ≥50%; and (5) absence of organic mitral disease. Procedural outcomes, 30-day survival, and echo findings are reported.

Results: Fourteen patients (71% women, mean age 77.9 years, Society of Thoracic Surgeons Predicted Risk of Mortality score 5.4%) were treated, including 11 via transseptal delivery and 3 via a transapical approach. Technical success and mitral regurgitation reduction from severe to none/trace were achieved in all cases. There were no cases of left ventricular outflow tract obstruction. All-cause mortality at 30 days was 14% (2/14). Class III/IV New York Heart Association status was reduced from 79% at baseline to 0% at 30 days. At 30 days, 11 of 12 surviving patients had an available echocardiogram; mitral regurgitation severity was trace/none in 90.9% (10/11) and mild in 9.1% (1/11).

Conclusions: The AltaValve system shows promising early procedural and clinical results for the unique anatomy of patients with atrial functional mitral regurgitation. Long-term clinical studies to demonstrate the benefit of this system are warranted.