Prognostic value of exercise right ventricular pulmonary arterial coupling in severe primary mitral regurgitation: new atrial fibrilation and unplanned cardiovascular hospitalization
Authors: Moura Ferreira S , Milani M , Bekhuis Y , Maarten F , Wouter L , Dhont S , Hoedemakers S , Stroobants S , Stassen J , Jasaityte R , Claessen G , Bertrand P , Pugliesi N , Verwerft J , Herbots L 
Published: January 2025

Abstract

Background
Exercise-induced pulmonary hypertension, characterized by mean pulmonary artery pressure over cardiac output slope (mPAP/CO slope) &gt; 3mmHg/L/min is associated with worse outcome in greater than moderate primary mitral regurgitation (PMR). However, the prognostic value of right ventricle to pulmonary artery coupling (RVPAc) is unknown.

Purpose
Assess the prognostic value of RVPAc; determine the additional value of exercise over rest RVPAc and compare these findings to the mPAP/CO slope.

Methods
The single center study included consecutive patients with greater than moderate PMR, no/discordant symptoms, left ventricular ejection fraction &gt;60% and absence of concomitant valvular disease greater than moderate or permanent atrial fibrillation (AF) referred to simultaneous CPET and exercise echocardiography (CPET-echo). A thorough echocardiographic assessment of right ventricle (RV) systolic function and RVPAc (TAPSE/sPAP, ratio of tricuspid annular plane systolic excursion over systolic pulmonary artery pressure) was performed using a dedicated RV window. mPAP and CO were obtained by Doppler echocardiography. Primary outcome was the composite of cardiovascular mortality, unplanned cardiovascular hospitalization and new AF episodes.

Results
A total of 159 consecutive patients (64±11 years, 59% men) were included. The event-free survival rate was 84% at 1 year and 78% at 2 years. Patients who fulfilled the primary combined endpoint had significantly larger left atrium indexed volumes (LAVi), lower left atrial strain and strain rate at rest and strain at intermediate exercise, lower absolute and normalized peak oxygen uptake (VO2peak), and a significantly higher mPAP/CO slope. They had significantly lower TAPSE, RV free wall S’ and TAPSE/sPAP. Sequentially adding intermediate or high exercise TAPSE/sPAP and percent-predicted VO2peak to the baseline predictive model (age, LAVi, mitral regurgitation grade and TAPSE/sPAP at rest) significantly improved the area under the curve (AUC) of the baseline logistic regression model (AUC: 0.71 vs. 0.80 and 0.71 vs. 0.81, p&lt;0.05, respectively), with LAVi and TAPSE/sPAP at intermediate or high exercise remaining as significant independent variables (although coupling assessment at high exercise technically less feasible). Replacing exercise TAPSE/sPAP with mPAP/CO yields models with comparable accuracy (Figure 1). Exercise TAPSE/sPAP &lt;0,6 was related to a higher event rate (Figure 2)

Conclusion
Decreased rest or exercise TAPSE/sPAP are single point measures of RVPAc, associated with adverse outcome in patients with greater than moderate PMR and no or discordant symptoms. Exercise TAPSE/sPAP has independent additional value over rest TAPSE/sPAP in predicting adverse events, with a similar accuracy as mPAP/CO slope. Exercise TAPSE/sPAP represents a potential alternative to mPAP/CO slope in this population, being readily available and simpler to adopt in clinical practice.