Comparative Effectiveness of Exercise Training for Patients With Chronic Thromboembolic Pulmonary Hypertension After Pulmonary Endarterectomy: A Systematic Review and Meta-Analysis

Background: Patients with chronic thromboembolic pulmonary hypertension (CTEPH) still experience reduced exercise capacity despite pulmonary endarterectomy (PEA). Exercise training improves the exercise capacity and quality of life (QoL) in patients with PH, but data on the effects of exercise training on these patients are scarce. The aim of this meta-analysis and systematic review was to evaluate the effectiveness and safety of exercise training in CTEPH after PEA. Methods: We searched the relevant literature published before January 2020 for the systematic review and meta-analysis using the PubMed, EMBASE, and Cochrane Library databases. The primary outcome was a change in the 6-min walking distance (6 MWD). We also assessed the effect of exercise on the peak oxygen uptake (VO(2)) or peak VO(2)/kg, oxygen uptake anaerobic threshold, workload, oxygen pulse, hemodynamics, arterial blood gases, oxygen saturation, N-terminal pro-brain-type natriuretic peptide (NT-proBNP), quality of life (QoL) and pulmonary function tests. Results: We included 4 studies with 208 exercise-training participants. In the pooled analysis, short-term exercise training can improve the 6 MWD of 58.89 m (95% CI: 46.26–71.52 m, P < 0.0001). There was a significant increase in the peak VO(2)/kg or peak VO(2) after exercise training (3.15 ml/min/kg, 95% CI: 0.82–5.48, P = 0.008; 292.69 ml/min, 95% CI: 24.62–560.75, P = 0.032, respectively). After exercise training, the maximal workload and O(2) pulse significantly improved. Three months of exercise training increased the right ventricular ejection fraction by 3.53% (95% CI: 6.31–11.94, P < 0.00001, I(2) = 0) independently of PEA surgery. In addition, NT-proBNP plasma levels significantly improved with exercise training after PEA [weighted mean difference (WMD): −524.79 ng/L, 95% CI: 705.16 to −344.42, P < 0.0001, I(2) = 0]. The partial pressure of oxygen and pH improved progressively over 12 weeks of exercise training (WMD: 4 mmHg, 95% CI: 1.01–8.33, P = 0.01; WMD: 0.03, 95% CI: 0.02–0.04, P < 0.0001, respectively). Subscales of the QoL measured by the SF-36 questionnaire had also improved. In addition, exercise training was well-tolerated with a low dropout rate, and no major adverse events occurred during exercise training. Conclusion: Exercise training may be associated with a significant improvement in the exercise capacity and QoL among CTEPH patients after PEA and was proven to be safe. However, more large-scale multicentre studies are needed to confirm the effectiveness and safety of exercise training in CTEPH patients after PEA. PROSPERO registration number: CRD42021235275.