Integrated Atrial and Ventricular Strain Assessment in Patients With Severe Degenerative Mitral Regurgitation Undergoing Surgery

BACKGROUND Current guidelines for degenerative mitral regurgitation (MR) emphasize left ventricular (LV) dysfunction. However, subclinical alterations in left atrial (LA) or LV strain may manifest earlier in severe MR. OBJECTIVES This study sought to determine whether combined LA and LV strain measurements improve long-term mortality prediction in severe degenerative MR, especially in asymptomatic individuals. METHODS This retrospective derivation cohort included 1,314 patients (mean age: 55 ± 13 years; 35% women) who underwent valve repair or replacement for severe MR. Preoperative peak atrial longitudinal strain (PALS) and LV-global longitudinal strain (GLS) were measured. Patients were categorized into 4 groups by using spline-derived thresholds (PALS: <21.4%; LV-GLS: >-20.5%). The primary outcome was all-cause mortality (median follow-up, 8.4 years). External validation included 605 independent patients. RESULTS Impaired PALS (adjusted HR [aHR]: 2.11; P < 0.001) and impaired LV-GLS (aHR: 1.66; P = 0.008) were independently associated with high mortality. The group with both impaired PALS and LV-GLS demonstrated the worst outcome (aHR: 2.50; P < 0.001). In asymptomatic patients (n = 900), the combined use of both strain parameters outperformed traditional LV dysfunction criteria (LV ejection fraction ≤60% or LV end-systolic dimension ≥40 mm), thereby significantly improving net reclassification (net reclassification index = 0.436; P < 0.001) and discrimination (integrated discrimination improvement = 0.024; P = 0.003). Subgroup analyses demonstrated that the prognostic contribution of each strain parameter varied by the functional status of the other chamber. External validation confirmed these associations. CONCLUSIONS Concomitant impairment of both PALS and LV-GLS identified patients at the highest mortality risk. These findings support an integrated atrial-ventricular strain assessment to improve prognostic stratification, particularly in asymptomatic patients with severe degenerative MR who are undergoing MV surgery.