Exercise pulmonary hypertension in chronic thromboembolic pulmonary disease: A right heart catheterization study

Many patients with chronic thromboembolic pulmonary disease (CTEPD) suffer from exertional dyspnea. It is unclear if CTEPD is associated with exercise pulmonary hypertension (ePH). This cross-sectional study aimed to determine the occurrence of ePH in patients with CTEPD and to identify the haemodynamic changes during exercise. We recruited 36 patients with persistent dyspnoea and residual perfusion defects by ventilation/perfusion scintigraphy from a large cohort of patients with previous pulmonary embolism. All patients underwent exercise right heart catheterization before being classified into the following groups: (1) CTEPD without ePH; comprising patients with normal mean pulmonary artery pressure (mPAP) of ≤20 mmHg, but with mPAP/cardiac output (CO) slope of ≤3 mmHg/L/min, (2) CTEPD with ePH (CTEPD-ePH); those with CTEPD with an mPAP/CO slope of >3 mmHg/L/min, (3) chronic thromboembolic pulmonary hypertension (CTEPH); those with mPAP >20 mmHg, pulmonary arterial wedge pressure (PAWP) ≤ 15 mmHg and pulmonary vascular resistance >2 WU. The postcapillary contribution during exercise was considered present if the PAWP/CO slope of >2 mmHg/L/min. CTEPD without resting pulmonary hypertension (PH) was present in 29 (81%) of the 36 patients, of whom six (21%) had ePH, while five (14%) had CTEPH. Two patients had unclassified PH. Two (33%) of the six patients with CTEPD-ePH had a PAWP/CO slope of >2 mmHg/L/min, compared with two (40%) of the five of those with CTEPH. In conclusion, about 20% of patients with CTEPD and exertional dyspnoea had ePH. Exercise right heart catheterization revealed a notable proportion of patients with postcapillary contribution.