The GeoForm Annuloplasty Ring for the Surgical Treatment of Functional Mitral Regurgitation in Advanced Dilated Cardiomyopathy

Objective: To assess the results of the three-dimensional (3D)-shaped GeoForm ring for the treatment of functional mitral regurgitation (FMR).

Methods: Seventy-four patients with severe FMR and systolic dysfunction underwent GeoForm ring implantation. Forty-six patients (62%) were in the New York Heart Association (NYHA) class III-IV. Concomitant procedures were coronary artery bypass grafting (CABG) (33 patients (pts)), tricuspid repair (23 pts), atrial fibrillation ablation (20 pts), aortic valve replacement (eight pts) and left-ventricular (LV) reconstruction (five pts).

Results: Hospital mortality was 9%. Three more patients died after hospital discharge. Overall survival was 81.1 ± 6.6% at 3.5 years. The 67 hospital survivors underwent clinical and echocardiographic follow-up at a mean follow-up period of 1.9 ± 1.25 years (median 1.7 years). MR was absent or mild in 83% of the patients (56/67), moderate in 7% (5/67), and moderate to severe in the remaining 9% (6/67). At 3.5 years, overall freedom from MR ≥ 3+ was 85.1 ± 8% and freedom from MR ≥ 2+ was 75.1 ± 8.6%. Statistical analysis identified preoperative asymmetric tethering with prevalent restricted motion of the posterior leaflet as the only predictor of recurrence of MR ≥ 2+ (hazard ratio (HR) 6.1, p=0.005). Reverse LV remodeling was demonstrated in 31 of the 54 patients eligible for this specific analysis (31/54, 57%): Both LV end-diastolic and end-systolic volumes indexed significantly decreased (both p=0.0001) as well as systolic pulmonary artery pressure (SPAP) (p=0.006). Ejection fraction increased from 33 ± 8% to 43 ± 8% (p<0.0001). Stress echocardiography was performed in a subgroup of eight patients. Mean mitral area at rest was 2.2 ± 0.3 cm² and did not change during stress. Cardiac output significantly increased in all patients during exercise. Although mean and peak transmitral gradients were 3.3 ± 1.3 and 8.1 ± 2.2 mmHg at rest and 6.6 ± 2.5 and 14.8 ± 3.9 mmHg under stress, respectively (both p<0.003), the increase in SPAP was not statistically significant (28 ± 3.0 vs 31 ± 7.5 mm Hg, p=0.17), revealing a preserved cardiac adaptation to exercise.

Conclusions: The GeoForm ring is effective in relieving FMR in most of the patients with dilated cardiomyopathy. In presence of prevalent restricted motion of the posterior leaflet, recurrence of significant MR is more likely to occur. Clinically relevant mitral stenosis was not detected during exercise.