The Role of Global Longitudinal Strain in the Follow-Up of Asymptomatic Patients with Chronic Primary Mitral Regurgitation

Abstract

Background/Objectives: In patients with chronic primary mitral regurgitation (MR), postoperative persistent left ventricular (LV) dysfunction underlines the lack of a sensitive parameter that can identify subclinical LV dysfunction and optimize the timing of intervention. Left ventricular global longitudinal strain (LV-GLS) is a measure of the longitudinal left ventricular systolic function, with prognostic significance. Its role in the follow-up of asymptomatic patients with MR is, however, poorly defined. The aim of this study was to assess the relative changes in LV-GLS in a cohort of MR patients and to correlate these changes with the need for intervention during a follow-up period. Methods: We conducted a prospective study on a cohort of 218 patients, divided into three subgroups according to MR severity (mild, moderate, severe). LV-GLS was measured at baseline and every six months during a median follow-up period of 30 months. The composite endpoint was the occurrence of heart failure symptoms, hospitalization for heart failure, LVEF < 60%, LVEDD > 45 mm, new onset atrial fibrillation, or cardiovascular death. Results: Patients with moderate and severe MR had a significantly lower GLS at baseline than those with mild MR (19.5% and 19.1% versus 22.3%, p < 0.01) despite a normal LVEF in all subgroups. The relative decrease in LV-GLS occurred earlier (at 12 months vs. 24 months) and was more evident in patients with moderate and severe MR (13.6% and 14.5%, respectively) versus patients with mild MR (6.72%). The baseline LV-GLS being under 18% and a relative decrease of over 10% in GLS were independent predictors of a composite outcome (HR = 1.59, CI 95% 1.17–2.86; HR = 1.74, CI 95% 1.2–2.91, p < 0.01). Conclusions: LV-GLS is a valuable monitoring tool for asymptomatic MR patients, a relative decrease > 10% in GLS may be predictive for the need for valve intervention.