Transcatheter Edge-to-Edge Repair for SAM-Related Mitral Regurgitation in Patients With HCM: The TRANSPARENT Registry.

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a genetic disorder characterized by left ventricular (LV) hypertrophy, LV outflow tract obstruction, systolic anterior motion (SAM), and subsequent mitral regurgitation (MR). Although its risk/benefit profile remains unclear, transcatheter mitral edge-to-edge repair (M-TEER) may be beneficial for patients at high or prohibitive surgical risk.

OBJECTIVES

The purpose of this study was to evaluate the safety and efficacy of M-TEER in patients with obstructive HCM and moderate-to-severe or severe SAM-related MR.

METHODS

Retrospective, international, multicenter study including 35 symptomatic patients treated with M-TEER at 12 centers. Mitral Valve Academic Research Consortium (MVARC) definitions were applied. Echocardiographic and clinical outcomes were assessed at discharge, 30 days, 1 year, and last available follow-up.

RESULTS

MVARC technical, 30-day device, and procedural success were achieved in 94%, 91%, and 88% of the cases, respectively. MR <2 was achieved in 97% of patients. LVOT gradient decreased from 62.0 mm Hg (Q1-Q3: 35.5-92.0 mm Hg) to 16.0 mm Hg (Q1-Q3: 12.0-22.0 mm Hg); P < 0.05, and the reduction persisted at a median follow-up of 523 days. NYHA functional class I/II increased from 31% to 88% at last follow-up. The composite outcome (all-cause death, admission for acute decompensated heart failure, M-TEER re-do, surgical mitral valve replacement) occurred in 26% of the cases, mainly driven by acute decompensated heart failure.

CONCLUSIONS

M-TEER appears to be a feasible and safe therapeutic option for anatomically suitable patients with obstructive HCM, LV outflow tract obstruction, and SAM-related MR who are at high or prohibitive surgical risk. Larger-scale data are warranted to further elucidate the role of M-TEER in this subset of patients.