Efficacy of native T1 mapping for patients with non-ischemic cardiomyopathy and ventricular functional mitral regurgitation undergoing transcatheter edge-to-edge repair

Abstract Background The objectives of this study were to investigate the efficacy of LV myocardial damage assessment by native T1 mapping obtained with cardiac magnetic resonance (CMR) for symptomatic heart failure (HF) patients with non-ischemic cardiomyopathy (NICM) and ventricular functional mitral regurgitation (VFMR) undergoing transcatheter edge-to-edge repair (TEER). Methods We studied 40 symptomatic HF patients with NICM and VFMR undergoing TEER. LV myocardial damage was defined as the native T1 Z-score which was converted from native T1 value obtained with CMR before TEER. The primary endpoint was defined as first re-hospitalization for HF or cardiovascular death over a median follow-up period of 12 months after TEER. Results Multivariable Cox-proportional hazards analysis showed that a native T1 Z-score was the only independent parameter associated with cardiovascular events (hazard ratio: 3.40, 95% confidential interval: 1.51-7.67), and patients with native T1 Z-score < 2.41 experienced significantly fewer cardiovascular events than those with a native T1 Z-score ≥ 2.41 (log-rank P = 0.001). Moreover, such a low native T1 Z-score and more severe VFMR in an effective regurgitant orifice area (EROA) ≥ 0.30 cm2 was associated with fewer cardiovascular events than for a high native T1 Z-score of ≥ 2.41 and less severe VFMR of EROA < 0.30 cm2 (log-rank P = 0.002). Conclusion Assessment of baseline LV myocardial damage by means of native T1 Z-score obtained with CMR without the use of gadolinium-based contrast media is a valuable additional parameter for better management of symptomatic NICM patients with reduced LVEF and VFMR following TEER.