Persistent exercise intolerance after pulmonary endarterectomy for CTEPH

Aim Hemodynamic normalisation is the ultimate goal of pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH). However, whether normalisation of hemodynamics translates into normalisation of exercise capacity is unknown. The incidence, determinants and clinical implications of exercise intolerance after PEA are unknown. We performed a prospective analysis to determine the incidence of exercise intolerance after PEA, assess the relationship between exercise capacity and (resting) hemodynamics, and search for preoperative predictors of exercise intolerance after PEA.

Methods According to clinical protocol all patients underwent cardiopulmonary exercise testing (CPET), right heart catheterisation (RHC) and cardiac magnetic resonance (CMR) imaging before and 6 months after PEA. Exercise intolerance was defined as a peak VO₂<80% predicted. CPET parameters were judged to determine the cause of exercise limitation. Relationships were analysed between exercise intolerance and resting hemodynamics and CMR-derived right ventricular (RV) function. Potential preoperative predictors of exercise intolerance were analysed using logistic regression analysis.

Results 68 patients were included in the final analysis. 45 patients (66%) had exercise intolerance 6 months after PEA; in 20 patients this was primarily caused by a cardiovascular limitation. The incidence of residual PH was significantly higher in patients with persistent exercise intolerance (p 0.001). However, 27 out of 45 patients with persistent exercise intolerance had no residual PH. In the multivariate analysis, preoperative transfer factor for carbon monoxide (TLCO) was the only predictor of exercise intolerance after PEA.

Conclusions The majority of CTEPH patients has exercise intolerance after PEA, often despite normalisation of resting hemodynamics. Not all exercise intolerance after PEA is explained by the presence of residual PH, and lower preoperative TLCO was a strong predictor of exercise intolerance 6 months after PEA.