Chronic Thromboembolic Pulmonary Disease With Exercise Pulmonary Hypertension: A Noninvasive Model to Predict Exercise Hemodynamics

Abstract

Background: Chronic thromboembolic pulmonary disease corresponds to exercise impairment after a pulmonary embolism due to persistent chronic thrombi and exercise pulmonary hypertension (PH). Diagnosis requires exercise right heart catheterization (RHC), whereas data on noninvasive diagnosis are scarce.

Research question: Is there an association between noninvasive parameters and exercise PH among symptomatic patients with chronic thromboembolism?

Study design and methods: Data come from a prospective cohort of 92 patients with chronic thrombi and absence/only mild resting PH undergoing cardiopulmonary exercise testing and exercise RHC with concomitant echocardiography. Clinical, functional, imaging, and hemodynamic data were documented. Exercise PH was defined as mean pulmonary artery pressure/cardiac output slope > 3 mm Hg/L/min.

Results: The mean age of the patients was 52.7 ± 14.3 years, and 62.0% were male. A total of 37 patients (40.2%) developed exercise PH. Patients with exercise PH had lower peak oxygen consumption, lower peak exercise oxygen saturation, and higher ventilatory inefficiency. At rest and peak exercise, they had higher tricuspid regurgitation peak velocity (TRPV), lower tricuspid annular plane systolic excursion (TAPSE)/pulmonary artery systolic pressure (PASP) ratio, invasively higher pulmonary pulse pressure, and lower pulmonary artery compliance. Peak exercise aortic saturation, peak oxygen consumption, partial pressure of end-tidal CO₂ at first ventilatory threshold, TRPV, and TAPSE/PASP ratio were independent predictors of exercise PH. Two weighted risk scores including age, partial pressure of end-tidal CO₂ at first ventilatory threshold, and peak TRPV or peak TAPSE/PASP identified patients at low vs high risk of exercise PH.

Interpretation: Our results show that symptomatic patients with chronic thrombi and exercise PH had impaired right ventricular contractile reserve and augmented afterload assessed by cardiopulmonary exercise testing, exercise echocardiography, and exercise RHC. Two noninvasive multiparametric scores aided stratification of low vs high risk of exercise PH.

Keywords: cardiopulmonary exercise testing; chronic thromboembolic pulmonary disease; exercise echocardiography; exercise pulmonary hypertension; exercise right heart catheterization; right ventricular-pulmonary artery coupling; tricuspid regurgitation peak velocity.