Impact of increased transmitral gradients after undersized annuloplasty for chronic ischemic mitral regurgitation

Recent studies have demonstrated that undersized ring mitral annuloplasty (URMA) for chronic ischemic mitral regurgitation (CIMR) can induce iatrogenic mitral stenosis. The impact of this functional mitral stenosis on clinical and echocardiographic results is not well established.

125 consecutive URMA for CIMR were dichotomized according to postoperative mean trans-mitral gradient (Δp) into Group A (61 patients, >5 mm Hg) and Group B (64 patients, ≤5 mm Hg). Echocardiographic, clinical and functional outcomes were prospectively recorded and compared.

There were no hospital deaths. Intensive-care and hospital length of stay were comparable in the 2 groups (p=N.S.). Twenty-three months of actuarial survival was 73.2 ± 8.0%, without inter-group differences (log-rank p=0.627), actuarial freedom from congestive heart failure was 71.4 ± 5.6%, freedom from hospitalization was 59.8 ± 7.7%, without inter-group differences (p=0.497 and 0.393 respectively), and actuarial freedom from recurrent CIMR was 62.7 ± 10.4%, without group-difference (p=0.259), respectively. Both groups showed progressive improvement of NYHA (Time p=0.0001), with reduced diuretics (p=0.0001), and without inter-group differences (Group Time p=0.894 and 0.397 respectively). Both groups showed a constant improvement of left ventricular end-systolic diameters, ejection fraction, CIMR-grade, tricuspid insufficiency grading, indexed left ventricular mass, systolic pulmonary arterial pressure, and tricuspid annular plane systolic excursion (Time p=0.0001 for all), without intergroup differences (p=N.S. for all). However, left ventricular end-diastolic diameters were better remodeled in Group A (Group Time p=0.037), together with a higher mean trans-mitral Δp and a lower coaptation depth (Group Time p=0.0001 and 0.05 respectively). Left atrial diameter was ameliorated in Group B, but remained unchanged in Group A (p=0.168).

URMA cures CIMR. The induction of mild mitral stenosis did not affect clinical, functional and echocardiographic outcomes.