Right ventricular remodeling after transapical transcatheter mitral
valve implantation for severe mitral regurgitation.
Abstract
Background: Transapical transcatheter mitral valve implantation (TMVI)
may be a therapeutic option for patients with severe mitral
regurgitation (MR) excluded from cardiac surgery due to excessive risk.
Common reasons for exclusion from surgery are pulmonary hypertension and
right ventricular (RV) dysfunction. The effect of TMVI on RV function
has not previously been well-characterized. Objectives: The aim of this
study was to examine the procedural and 3-month impact of TMVI on RV
hemodynamics and remodeling. Methods: This was a multi-center,
retrospective, observational cohort study of patients with
>3+MR undergoing TMVI. Pre- and post-TMVI hemodynamics were
assessed with right heart catheterization. RV remodeling was assessed at
baseline, pre-discharge and at 3-months by echocardiography. Results:
Forty-six patients (age 72±9 years; 34 men) with ≥3+MR underwent TMVI
over a 5-year period. Successful device implantation was achieved in all
patients with abolition of MR (p<0.001) and reduction in
left-ventricular end-diastolic volume (p=0.001). RV stroke work index
increased intra-operatively (7±4g/m/beat/m² vs 11±5g/m/beat/m²;
p<0.001). At 3-months there were reductions in severity of
tricuspid regurgitation (TR) (p<0.001) and pulmonary artery
systolic pressure (PASP) (49±16mmHg vs 36±12mmHg; p<0.001),
and improvements in RV fractional area change (28±7% vs 34±9%,
p<0.001), tricuspid annular plane systolic excursion (TAPSE)
(1.0±0.3 vs 1.5±0.5cm, p=0.03), and RV free wall longitudinal strain
(-14.2±5.0 vs -17.6±7.3, p=0.05). Conclusions: Transapical TMVI results
in significant improvement of RV function that is sustained to 3 months
as evidenced by reductions in TR severity and PASP, and improvements in
RV fractional area change, TAPSE, and RV free wall longitudinal strain.