Comparison of Myocardial Mechanics Post Mitral Valve Repair with Leaflet Preservation vs. Leaflet Resection: A Sub-Analysis of the Randomized CAMRA CardioLink-2 Trial.

Background: Prior studies comparing leaflet resection vs. leaflet preservation for surgical repair of mitral regurgitation (MR) caused by prolapse have focused predominately on measurement of left ventricular ejection fraction without adjusting for loading conditions. This post hoc sub-analysis evaluated subclinical differences in myocardial mechanics pre- mitral valve (MV) repair, immediately after, and 1-year post-repair, as well as differences between leaflet resection and preservation strategies.

Methods: A total of 104 patients were randomized to the resection or preservation group for surgical treatment of posterior leaflet prolapse in the Canadian Mitral Research Alliance CardioLink-2 study. Speckle-tracking echocardiography was performed at baseline (pre-repair), immediately post-repair, and 1-year post repair. Global longitudinal strain (GLS) was compared at the three timepoints, as well as between leaflet preservation and resection groups using descriptive statistics. GLS was adjusted for LV end diastolic dimensions to adjust for loading conditions.

Results: The mean (SD) age of the participants was 65 ± 10 years, and 83% were male. The mean GLS pre-MV repair was -19.6% ± 5.4%, and did not differ between the leaflet resection and leaflet preservation groups. The mean GLS dropped to -12.8% ± 4.7 immediately post-repair (p=0.001 compared to pre-repair). One-year post-repair, the mean GLS improved to -16% ± 4% in both groups, but remained below pre-repair values, however, the GLS indexed to loading conditions was similar to pre-operative values. Pre-operative GLS was an independent predictor of post-operative reduced GLS independent of age, sex, body surface area, and repair strategy.

Conclusions: Mitral valve repair is associated with an immediate reduction in GLS, but when corrected for loading conditions, indexed GLS demonstrates complete preservation of LV function at 1 year. The leaflet preservation and resection techniques for surgical repair of MR have similar effects on myocardial mechanics 1-year post-repair. Pre-operative GLS may be used to predict LV myocardial mechanics 1 year post-operatively. (Trial registration number NCT02552771, https://clinicaltrials.gov/study/NCT02552771).