PhD Student Université Laval Quebec, Quebec, Canada
Background: Recent studies have demonstrated the incremental prognostic value of echocardiographic parameters of right ventricular (RV) function in the risk stratification of patients with primary mitral regurgitation (PMR). However, there remains uncertainty as to the optimal parameter to evaluate RV function in PMR. We hypothesized that the coupling of pulmonary arterial systolic pressure (PASP) and RV end-diastolic area (RVEDA) is a surrogate of RV wall stress and is thus associated with clinical outcomes in PMR patients.
METHODS AND RESULTS: The PASP•RVEDA parameter was measured in 209 patients (mean age: 60 ± 14 years; 52% men, 62% ≥ moderate PMR) enrolled between 2008 and 2022 in the prospective, observational and multicentric study PROGRAM (NCT01835054). Receiver operating characteristics curve was used to determine the optimal prognostic threshold of PASP•RVEDA associated with all-cause mortality or mitral valve surgery (median follow-up: 6.0 (2.9-9.0) years, 109[49%] events [15 deaths and 88 surgeries]). The feasibility of the PASP•RVEDA measurement was 96%. The intra-observer reproducibility of the novel parameter was (Intraclass correlation coefficient [ICC] [95% Confidence interval (CI)]: 0.94 [0.66– 0.98], p ≤ 0.001) while the inter-observer reproducibility was (ICC [95%CI]: 0.90 [0.64 – 0.96], p ≤ 0.001). The performance of the PASP•RVEDA parameter was comparable or better than that of the RV function and dilation parameters proposed by the American Society of Echocardiography guidelines. The optimal prognostic threshold of PASP•RVEDA was 680 mmHg•cm2. In univariate Cox regression analyses, continuous as well as dichotomic PASP•RVEDA were associated with higher risk of mortality or mitral valve surgery (Hazard ratio [HR] [95%CI]: 1.12 [1.02 – 1.22] per 100 mmHg•cm2 increment, p = 0.01 and HR [95%CI]: 1.77 [1.16 – 2.71], p = 0.01, respectively). When the population was divided into tertiles according to their PASP•RVEDA parameter, the second tertile presented significantly less mortality or mitral valve surgery (HR [95%CI]: 0.51 [0.31 – 0.84], p = 0.01). This association persisted in multivariate Cox regression analysis when adjusted for age, sex, NYHA functional class (I vs II), left ventricular end-diastolic diameter, indexed left atrium volume and E/A ratio (HR [95%CI]: 0.48 [0.25 – 0.93], p = 0.03).
Conclusion: This study suggests that PASP•RVEDA is a novel surrogate marker of RV wall stress readily available from measurements acquired in clinical routine and may be useful to predict clinical outcomes and to enhance risk stratification in asymptomatic patients with PMR.
