Tricuspid regurgitation in pulmonary arterial hypertension: relations with right ventricular function and prognosis

Abstract

Abstract Background Pulmonary arterial hypertension (PAH) is a devastating disease characterized by progressive pulmonary vascular remodeling and increased pulmonary vascular resistance (PVR), subsequent right ventricular (RV) failure and premature death (1). Progressive RV overload leads to RV dilatation, which in turn induces tethering of the tricuspid valve and functional valvular regurgitation (2,3). As such, severity and the progression of tricuspid regurgitation (TR), as evaluated by echocardiographic qualitative analysis, are reported to associate with a poor prognosis in PAH (4,5). However, it has remained unclear to what extent the severity of TR directly impacts RV hemodynamics and prognosis of PAH patients. Purpose This study aimed to explore the consequences of TR for RV function and prognosis in PAH using a volumetric analysis by cardiac magnetic resonance (CMR). Methods 92 PAH patients, mean pulmonary arterial pressure (mPAP) ≥25 mmHg and pulmonary artery wedge pressure ≤15 mmHg, with available CMR data from January 1st 2010 to August 31st 2021 were included in this study. TR volume was calculated as the difference between the stroke volume (SV) of RV and pulmonary artery (PA). TR severity was graded as no or mild (TR<30 mL), moderate (30≤TR<45 mL) and severe (TR≤45 mL). Hemodynamic assessment was performed by right heart catheterization. Event free survival was estimated from the time of the CMR scan to cardiopulmonary death or lung transplantation. Results In the studied cohort, 74% of PAH patients had no or mild TR, 16% had moderate TR, and 10% had severe TR (Table 1). A greater TR volume was characterized by increased NT-proBNP, increased mPAP, PVR and mean right atrial pressure (mRAP), and increased RV volume. Additionally, RVSV was higher while PASV was lower. There was no difference in RV ejection fraction (RVEF). Pearson correlation analysis showed a good correlation between TR volume and parameters of PAH severity, such as NT-proBNP, RV end-systolic volume (RVESV), mRAP and cardiac index (CI) (Figure 1). ROC curves analysis revealed that the optimal cut-off value of TR volume was 30 mL. Kaplan-Meier survival analysis demonstrated that TR volume ≥30 mL was strongly associated with a poor event free survival (Figure 2). Conclusion 26% of PAH patients had a TR volume 30 ≥mL. TR severity showed a good correlation with PAH disease severity. TR volume 30 ≥mL, i.e. moderate or severe TR, was strongly associated with a poor prognosis in PAH patients.TableFigure