Usefulness of cardiopulmonary exercise test combined with exercise stress echocardiography in mild chronic thromboembolic pulmonary disease

Abstract Purpose Chronic thromboembolic pulmonary disease (CTEPD) can lead to exercise limitations even without right ventricular (RV) dysfunction or pulmonary hypertension at rest. Combining exercise stress echocardiography with cardiopulmonary exercise testing (ESE‐CPET) for RV function and pressure changes combined measuring overall function may be useful for CTEPD evaluation. This study aims to investigate CPET and ESE results to elucidate the mechanisms of exercise limitation in mild CTEPD cases. Methods Among our CTEPD registry, 50 patients who performed both right heart catheterization data of mild disease (less than 30 mm Hg of mean pulmonary arterial pressure (mPAP)) and ESE‐CPET were enrolled. Echocardiography and CPET‐derived parameters were compared with hemodynamic parameters measured through right heart catheterization. Results Peak VO 2 (maximal oxygen consumption) was decreased in overall population (71.3 ± 16.3% of predictive value). Peak VO 2 during exercise was negatively correlate with mPAP and pulmonary vascular resistance at rest. A substantial increase in RV systolic pressure (RVSP) was observed during exercise (RVSP: pre‐exercise 37.2 ± 11.8 mm Hg, postexercise 64.3 ± 24.9 mm Hg, p ‐value < .001). Furthermore, RV function deteriorated during exercise when compared to the baseline (RV fractional area change: 31.5 ± 10.0% to 37.8 ± 7.0%, p ‐value < .001; RV global longitudinal strain: −17.1 ± 4.2% to −17.7 ± 3.3%, p ‐value < .001) even though basal RV function was normal. While an excessive increase in RVSP during exercise was noticed in both groups, dilated RV and RV dysfunction during exercise were demonstrated only in the impaired exercise capacity group. Conclusion CTEPD patients with mild PH or without PH exhibited limited exercise capacity alongside an excessive increase in RVSP during exercise. Importantly, RV dysfunction during exercise was significantly associated with exercise capacity. ESE‐CPET could aid in comprehending the primary cause of exercise limitation in these patients.