Exercise ventilation inefficiency and dynamic tricuspid regurgitation in heart failure

Abstract

Abstract Background Exercise ventilation inefficiency, i.e. increase slope of the relationship of ventilation (VE) vs carbon dioxide (VCO2) slope is a key prognostic indicator in heart failure (HF). Many determinants have been identified primarily related to the left heart and impaired reflexogenic control of VE. In parallel, the severity of tricuspid regurgitation (TR) at rest is increasingly recognized as an important determinant of functional status and prognosis. It is undefined whether VE inefficiency may be related to the dynamic TR during exercise. Purpose We tested the role of dynamic TR and its correlates to exercise VE inefficiency by combining cardiopulmonary exercise test (CPET) with echocardiography. Methods We prospectively studied stable HF patients with both reduced and preserved left ventricular ejection fraction (LVEF). Patients with severe pulmonary disease and those who underwent valve replacement or cardiac surgery were excluded. Mitral and tricuspid regurgitation degree were adjudicated accordingly to ESC Guidelines criteria. Demographics and clinical characteristics along with laboratory parameters including electrolytes, biomarkers of congestion (NT-proBNP), renal and liver function, were collected at the time of CPET. Dynamic TR was defined as worsening of TR grade from rest to stress detected by Doppler analysis. VE/VCO2 slope and peak oxygen consumption (pVO2) were compared between patients with dynamic TR (Group 1) vs non-dynamic TR (Group 2). Results Among 56 patients (66±13 years, 64% men, mean LVEF of 50±14%, 35% ischemic) 12% showed at least moderate mitral regurgitation and 16% patients had at least moderate TR at rest. TR jet velocity at rest and at peak exercise were associated with VE/VCO2 slope (r=0.36 and r=0.3 respectively, p value <0.05, Figure 1). A dynamic TR pattern (Group 1) appeared in 28 (50%) patients. No differences in clinical characteristics, laboratory parameters, LV ejection fraction, prevalence and degree of mitral regurgitation at rest and at peak were found between the two groups. Group 1 compared to Group 2 exhibited a lower right ventricular fractional area change at peak exercise (45% [41–50] vs 52% [44–62] p=0.03), lower median pVO2 (13.3 [10.4–17.5] vs 16.3 [13.9–21.8], respectively (p=0.04)) and higher VE/VCO2 slope (40.3 [33.1–44] vs 34.1 [29.2–38.8], p=0.01; Figure 2A and B). Conclusions Patients with a dynamic TR pattern during CPET imaging exhibit a worse VE efficiency that correlates with TR extent. These data prospect, for the first time, an interaction between dynamic TR and ventilatory pattern during exercise in HF whose relevance may translate in targeting the right heart appropriately. Funding Acknowledgement Type of funding sources: None.