Effect of Transcatheter Mitral Valve Repair on Left Atrial Kinetic Energy in Chronic Mitral Regurgitation
Author: Michael Biersmith, MD, Additional Authors**
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Background: Left atrial kinetic energy (LAKE) is a marker of left atrial work and increases in LAKE are associated with left atrial failure and atrial fibrillation in patients with mitral stenosis and mitral regurgitation. LAKE has not been studied in patients who have received transcatheter mitral valve repair with MitraClip device for management of chronic moderately-severe and severe mitral regurgitation.
Objective: Measure the effect of transcatheter mitral valve repair with MitraClip on LAKE in patients with chronic moderate-severe and severe mitral regurgitation.
Methods: We retrospectively reviewed patients who had received MitraClip for chronic primary (i.e., floppy mitral valve/ mitral valve prolapse) or secondary (i.e., functional) moderately-severe (grade 3+) or severe mitral regurgitation (grade 4+) between July 2014 and September 2019. Peak LAKE was calculated by the formula: ½MV2 (where M (mass) = LA stroke volume x 1.06 (the density of blood) and V = transmitral A-wave velocity) expressed in dyne·cm·103. Apical 2- and 4-chamber views were used to calculate left atrial stroke volume by Simpson’s method discs. The active or “booster pump” phase of left atrial contraction was defined as the onset of the P-wave until end-diastole. LAKE, stroke volume, Doppler transmitral A-wave velocity, and mean mitral gradients was compared between baseline and post-procedural echocardiography obtained an average of 10 months after transcatheter mitral repair. Patients with incomplete or poor-quality echo data, mixed etiologies of valvular disease, and significant arrhythmias, including atrial fibrillation and frequent PVCs, were excluded. Two-tailed paired Student’s t-test was used to for comparison of means. p < 0.05 was considered significant. Values are expressed as mean ± standard deviation.
Results: 39 patients who underwent MitraClip procedure were screened. 12 patients were included in the final analysis, 9 with primary mitral regurgitation and 3 with functional mitral regurgitation. Each patient received an average of 1.6 clips. In comparison to baseline, transmitral A-wave velocities significantly increased (87.8 ± 41 cm/s2 vs. 138.5 ± 44 cm/s2, p < 0.001) after MitraClip. Left atrial stroke volume did not significantly change (16 ± 7.8 cm3 vs. 17.5 ± 13.3 cm3, p = 0.72). There was a statistically significant increase in LAKE (71 ± 64 dyne·cm·103 vs 177.5 +/- 168 dyne·cm·103, p = 0.008). Mean mitral stenosis gradients significantly increased (3.3 ± 2.0 mm Hg vs. 5.7 ± 2.1 mm Hg, p < 0.01).
**Additional Authors:
Michael Biersmith, MD, The Ohio State University Wexner Medical Center
David Orsinelli, MD, The Ohio State University Wexner Medical Center
Thura Harfi, MD, The Ohio State University Wexner Medical Center
Scott Lilly, MD, PhD, The Ohio State University Wexner Medical Center
Konstantinos Dean Boudoulas, MD, The Ohio State University Wexner Medical Center
