Understanding the Effects of Mitral Transcatheter Edge-to-Edge Repair on Left Ventricular Function Using Pressure-Volume Loops

Background: Mitral transcatheter edge-to-edge repair (M-TEER) is an effective treatment for mitral regurgitation (MR) patients. Objectives: The aim of this research was to study M-TEER effects on left atrial (LA) and left ventricular (LV) functions. Methods: LV function was evaluated using conductance catheters for pressure volume loops in 22 patients with primary MR and a control group of 17 heart transplant recipients with normal function. LA pressures and LA operating chamber stiffness were obtained using fluid-filled catheters. MR severity was assessed by echocardiography. Results: Compared to the control group, primary MR patients had increased LV volumes, diastolic pressures, tau, and LV chamber stiffness constant (all P ≤ 0.01). After M-TEER, LV and LA volumes and pressures and MR regurgitant volume decreased (all P < 0.05), without significant change in LV preload recruitable stroke work (50.7 ± 14 vs 47 ± 17 mm Hg), end systolic pressure/volume (1.67 ± 0.69 vs 1.66 ± 0.62 mm Hg/mL), pressure volume area (11,493 ± 3,428 vs 11,898 ± 5,256 mm Hg. mL), and chamber stiffness constant (0.05 ± 0.07 vs 0.03 ± 0.02, all P > 0.20). Post-M-TEER, patients with LA V wave pressure ≥20 mm Hg had significantly higher LA operating chamber stiffness, tau, and LV chamber stiffness constant vs patients with V wave pressure <20 mm Hg all (P < 0.05). Conclusions: After M-TEER, there is no significant change in invasive indices of LV contractility. Tau is significantly prolonged after M-TEER, whereas LV chamber stiffness constant is abnormally increased before M-TEER without a significant change afterward. Patients with LA “V” wave pressure ≥20 mm Hg after M-TEER have worse LV diastolic function and higher LA operating chamber stiffness.