Right ventricular-arterial coupling and exercise-induced tricuspid regurgitation

Abstract Background Right Ventricular-pulmonary Artery (RV-PA) coupling is prognostic in a variety of cardiovascular disorders, including heart failure with preserved ejection fraction, pulmonary hypertension and severe aortic stenosis. The functional aspects of RV-PA coupling are less investigated than rest ones especially in what is their interaction with tricuspid regurgitation (TR). Purpose We sought to understand the association of RV-PA coupling with extent of exercise induced TR by combining gas exchange abnormalities through cardiopulmonary exercise test (CPET) imaging. Methods We prospectively studied patients with indication to perform a CPET imaging test due to dyspnoea and underlying heart disease of any left ventricular ejection fraction. Demographics, baseline characteristics, echo and CPET parameters [(e.g. VE/VCO2 slope and peak oxygen consumption (pVO2)] were evaluated across 3 sub-cohorts phenotyped according to TR severity pattern at rest and at peak exercise . Mitral and tricuspid regurgitation degree were adjudicated accordingly to ESC guidelines. RV-PA coupling function was assessed through the ratio between tricuspid annular plane systolic excursion (TAPSE), and non-invasive pulmonary artery systolic pressure (PASP) with echocardiography. Dynamic TR was defined as detection of at least moderate TR grade from rest to stress. Results A total of 73 patients (age 67±13 years, 52% men), with a mean LVEF of 50±14% were studied. Overall 50 (69%) patients had less than moderate TR which did not increase during stress (Controls), 11 (15%) patients exhibited a dynamic TR pattern (Group 1), and 12 (16%) already had significant TR at rest (Group 2). TAPSE/PASP at rest and peak exercise were significantly lower in Group 1 and 2 compared to Controls (Figure), while the mean PAP/cardiac output (CO) ratio at rest and at peak exercise were significantly higher (Table). As to gas exchange data, Group 1 and 2 exhibited a lower median peak VO2, while Group 2 patients had also a higher median VE/VCO2 slope compared to Controls (Table). 10 (14%) patients showed at least moderate mitral regurgitation (significant MR) at rest and the prevalence of significant MR at peak was higher in group 1 and 2 compared to Controls (Table). A weak negative correlation was found between TAPSE/PASP slope and E/e’ ratio at peak exercise (r =-0.435, p<0.01). Conclusion In presence of exercise dyspnoea, patients with dynamic TR during maximal exercise exhibit a worse degree of RV-PA coupling and gas exchange profile compared to the group without significant exercise-induced TR. Moreover, the exercise-induced TR profile behaves similarly to the one of those presenting with moderate to severe TR already detectable at rest. Phenotyping dynamic TR and RV-PA warrants further evidence on therapies and outcomes prediction in exertional dyspnoea patients.FigureTable