Exercise Stress Echocardiography of the Right Ventricle and Pulmonary Circulation

BACKGROUND

Exercise echocardiography is used for assessment of pulmonary circulation and right ventricular function, but limits of normal and disease-specific changes remain insufficiently established.

OBJECTIVES

The objective of this study was to explore the physiological vs pathologic response of the right ventricle and pulmonary circulation to exercise.

METHODS

A total of 2,228 subjects were enrolled: 375 healthy controls, 40 athletes, 516 patients with cardiovascular risk factors, 17 with pulmonary arterial hypertension, 872 with connective tissue diseases without overt pulmonary hypertension, 113 with left-sided heart disease, 30 with lung disease, and 265 with chronic exposure to high altitude. All subjects underwent resting and exercise echocardiography on a semirecumbent cycle ergometer. All-cause mortality was recorded at follow-up.

RESULTS

The 5th and 95th percentile of the mean pulmonary artery pressure-cardiac output relationships were 0.2 to 3.5 mm Hg.min/L in healthy subjects without cardiovascular risk factors, and were increased in all patient categories and in high altitude residents. The 5th and 95th percentile of the tricuspid annular plane systolic excursion to systolic pulmonary artery pressure ratio at rest were 0.7 to 2.0 mm/mm Hg at rest and 0.5 to 1.5 mm/mm Hg at peak exercise, and were decreased at rest and exercise in all disease categories and in high-altitude residents. An increased all-cause mortality was predicted by a resting tricuspid annular plane systolic excursion to systolic pulmonary artery pressure <0.7 mm/mm Hg and mean pulmonary artery pressure-cardiac output >5 mm Hg.min/L.

CONCLUSIONS

Exercise echocardiography of the pulmonary circulation and the right ventricle discloses prognostically relevant differences between healthy subjects, athletes, high-altitude residents, and patients with various cardio-respiratory conditions. (Right Heart International NETwork During Exercise in Different Clinical Conditions; NCT03041337).

Prognostic Importance of Pulmonary Arterial Capacitance in Acute Decompensated Heart Failure With Preserved Ejection Fraction

Background

Although the prognostic importance of pulmonary arterial capacitance (PAC; stroke volume/pulmonary arterial pulse pressure) has been elucidated in heart failure with reduced ejection fraction, whether its significance in patients suffering from heart failure with preserved ejection fraction is not known. We aimed to examine the association of PAC with outcomes in inpatients with heart failure with preserved ejection fraction.

Methods and Results

We prospectively studied 705 patients (median age, 83 years; 55% women) registered in PURSUIT‐HFpEF (Prospective Multicenter Observational Study of Patients With Heart Failure With Preserved Ejection Fraction). We investigated the association of echocardiographic PAC at discharge with the primary end point of all‐cause death or heart failure rehospitalization with a mean follow‐up of 384 days. We further tested the acceptability of the prognostic significance of PAC in a subgroup of patients (167/705 patients; median age, 81 years; 53% women) in whom PAC was assessed by right heart catheterization. The median echocardiographic PAC was 2.52 mL/mm Hg, with a quartile range of 1.78 to 3.32 mL/mm Hg. Univariable and multivariable Cox regression testing revealed that echocardiographic PAC was associated with the primary end point (unadjusted hazard ratio, 0.82; 95% CI, 0.72–0.92; P=0.001; adjusted hazard ratio, 0.86; 95% CI, 0.74–0.99; P=0.035, respectively). Univariable Cox regression testing revealed that PAC assessed by right heart catheterization (median calculated PAC, 2.82 mL/mm Hg) was also associated with the primary end point (unadjusted HR, 0.70; 95% CI, 0.52–0.91; P=0.005).

Conclusions

A prospective cohort study revealed that impaired PAC diagnosed with both echocardiography and right heart catheterization was associated with adverse outcomes in inpatients with heart failure with preserved ejection fraction.

Registration

URL: https://upload.umin.ac.jp/cgi‐open‐bin/ctr_e/ctr_view.cgi?recptno=R000024414. Unique identifier: UMIN000021831.

Dynamic right ventricular-pulmonary arterial uncoupling during maximum incremental exercise in exercise pulmonary hypertension and pulmonary arterial hypertension

Despite recent advances, the prognosis of pulmonary hypertension (PH) remains poor. While the initial insult in PH implicates the pulmonary vasculature, the functional state, exercise capacity, and survival of such patients are closely linked to right ventricular (RV) function. In the current study, we sought to investigate the effects of maximum incremental exercise on the matching of RV contractility and afterload (i.e. right ventricular-pulmonary arterial [RV-PA] coupling) in patients with exercise PH (ePH) and pulmonary arterial hypertension (PAH). End-systolic elastance (Ees), pulmonary arterial elastance (Ea), and RV-PA coupling (Ees/Ea) were determined using single-beat pressure-volume loop analysis in 40 patients that underwent maximum invasive cardiopulmonary exercise testing. Eleven patients had ePH, nine had PAH, and 20 were age-matched controls. During exercise, the impaired exertional contractile reserve in PAH was associated with blunted stroke volume index (SVI) augmentation and reduced peak oxygen consumption (peak VO₂ %predicted). Compared to PAH, ePH demonstrated increased RV contractility in response to increasing RV afterload during exercise; however, this was insufficient and resulted in reduced peak RV-PA coupling. The dynamic RV-PA uncoupling in ePH was associated with similarly blunted SVI augmentation and peak VO₂ as PAH. In conclusion, dynamic rest-to-peak exercise RV-PA uncoupling during maximum exercise blunts SV increase and reduces exercise capacity in exercise PH and PAH. In ePH, the insufficient increase in RV contractility to compensate for increasing RV afterload during maximum exercise leads to deterioration of RV-PA coupling. These data provide evidence that even in the early stages of PH, RV function is compromised.