In degenerative mitral regurgitation a combined speckle tracking analysis predicts right ventricular to pulmonary circulation uncoupling
Authors: Barki M , Stella S , Ancona F , Margonato D , Biondi F , Fiore G , Rizza V , Fanti D , Paci G , Ingallina G , De Bonis M , Castiglioni A , Maisano F , Slavich M , Agricola E 
Published: January 2025

Abstract

Background
Global Longitudinal Strain (GLS) and left atrial (LA) strain evaluation by Speckle Tracking Echocardiography (STE) have emerged as prognostic index in patients affected by degenerative mitral regurgitation (DMR). In this setting, the coupling between right ventricular (RV) function and the pulmonary circulation (PC) has demonstrated to be associated with cardiovascular outcome. However, the prevalence of RV to PC uncoupling in patients undergoing surgery for DMR and its relationship with left ventricular (LV) and LA functioning has poorly been investigated.

Aims
To investigate the determinants of longitudinal LV systolic and LA function, and their association with RV-to-PC coupling in a cohort of patients with DMR undergoing mitral valve surgery.

Methods
380 consecutive patients affected by DMR who underwent mitral surgery (repair or replacement) were retrospectively enrolled. LV longitudinal systolic function was studied with GLS and LA function was evaluated analyzing LA strain at peak relaxation (Global peak atrial longitudinal strain). RV-to PC coupling was studied with TAPSE/PAPS ratio considering a cut-off of 0,40 mm/mmHg and correlated with LV and LA strain. Speckle tracking echocardiography was performed offline and all patients were in sinus rhythm.

Results
A total of 380 eligible patients (mean age 55±14 y, 66% male) who were admitted for mitral valve surgery at San Raffaele hospital (85% repair, 15% replacement) for hemodynamically significant DMR were retrospectively enrolled. Mean hospital stay was 11±8 days. At baseline, 70% of patients exhibited an increased left ventricular (LV) and left atrial (LA) size. However, a preserved LA reservoir function (mean GPALS 27.6±11) and LV longitudinal systolic function (mean GLS -20.8±3) was found. Interestingly, GLS emerged as a strong determinant of LA reservoir strain with a significant direct correlation observed between GLS and GPALS values (r = 0.4 CI 95% 0.3-0.6; p&lt;0.01, Figure 1). Additionally, when correlated with TAPSE/PAPS ratio, patients with lower TAPSE/PAPS (&lt;0.4 mm/mmHg) exhibited significantly lower values of Global Longitudinal Strain and LA reservoir strain (TAPSE/PAPS&lt;0.4 mm/mmHg: GLS -17±7% and GPALS 22.7±11.3% vs TAPSE/PAPS≥0.4 mm/mmHg: GLS -22±8% and GPALS 27.8±12.7%; p&lt;0.01, Figure 2).

Conclusions
In DMR, LV GLS represents a strong determinant of LA reservoir function with a strong association between echo-derived measures of LA mechanics and LV longitudinal systolic function. In this context, a combined speckle-tracking analysis of LV and LA dynamics was able to predict the right ventricular coupling with the pulmonary circulation, underlying that the deterioration of LV and LA dynamics favors pulmonary venous congestion and vascular remodeling, ultimately affecting the right ventricle. A multiparametric approach in this subset of patients appears of relevance to ease risk-stratification, potentially improving the long-term outcome.