Intraprocedural direct left atrial and wedge pressure correlation during transcatheter mitral valve repair: Results from a single center registry

OBJECTIVES: This study investigates the correlation of occlusive wedge pressure (WP) with direct left atrial (LA) pressure in patients with severe mitral regurgitation (MR) undergoing transcatheter mitral valve repair (TMVr) with MitraClip. BACKGROUND: There is interest in acquiring objective hemodynamic parameters for intraprocedural guidance in patients undergoing MitraClip. METHODS: The study included 94 patients with severe MR at prohibitive surgical risk who underwent MitraClip at the University of California Davis Medical Center between 2014 and 2016. RESULTS: An average of 1.8 ± 0.7 clips were used to achieve MR grade of 2+ or less in 99% of patients. Correlation analysis of all (n = 236) pre-clip, inter-clip, and final-clip WP and LA pressures yielded a Pearson's R (r) of 0.85 and 0.79 for mean WP vs mean LA and WP V vs LA V, respectively. Median LA V to mean LA ratio (LAV:mLA) was 1.75 (IQR 1.5-1.9). 79% (n = 74) of patients had LAV:mLA ratio ≥ 1.5 with associated WP V vs LA V correlation (r) of 0.83. In patients with LAV:mLA ratio < 1.5, the correlation (r) was 0.69. Baseline characteristics were not significantly different between patients with LAV:mLA ratio ≥ 1.5 and patients with LAV:mLA ratio < 1.5. Post-procedure, median LA V: mean LA ratio decreased from 1.75 to 1.4, P = 0.0001. CONCLUSIONS: Correlation between WP and direct LA pressure in patients with severe MR undergoing Mitraclip is modest. Caution is advised when using WP to approximate LA pressure intraprocedurally, especially in patients with baseline low LAV:mLA ratios.