Long-Term Recovery of Exercise Ability After Pulmonary Endarterectomy for Chronic Thromboembolic Pulmonary Hypertension

Background The exercise capacity of patients with thromboembolic pulmonary hypertension was investigated to clarify the long-term effects of pulmonary endarterectomy. This capacity was assessed by measuring cardiopulmonary factors during cardiopulmonary exercise testing at the maximal level of exercise and a 6-minute walk test at the submaximal level. Their survival rate was also determined. Methods We conducted a retrospective review of the clinical records of 102 patients who underwent pulmonary endarterectomy (63 women; median age, 53 years). Results Eight (7.8%) hospital mortalities were encountered. Three late mortalities due to fulminant hepatitis, breast cancer, and pneumonia in a patient under steroid therapy were unrelated to pulmonary endarterectomy. The actual survival rate including hospital mortalities was 90.9% at 3 years and 84.0% at 5 years. All hemodynamic measurements significantly improved and reached a plateau 1-month after endarterectomy. The cardiopulmonary exercise test at the maximal exercise level revealed that peak oxygen uptake (VO2) baseline was 13.8 ± 3.2 mL/min/kg, and at 1-month was 16.2 ± 4.2 mL/min/kg (p = 0.0015) and ventilatory response to carbon dioxide production (VE-VCO2) slope baseline was 46.5 ± 8.4 mL/min/kg, and at 1-month was 39.9 ± 7.4 (p = 0.0006), which gradually and significantly improved during the first year after endarterectomy (peak VO2, 19.9 ± 3.9 mL/min/kg [p < 0.0001] and VE-VCO2 slope, 33.2 ± 5.4 mL/min/kg [p <0.0001]). The 6-minute walk test, which reflects the systemic response at the submaximal level of functional capacity, showed that the walking distance gradually and significantly increased for up to 1 year after endarterectomy (baseline, 358 ± 102 meters [m]; at 1-month, 433 ± 105 m; and at 1-year, 490 ± 80 m [p < 0.0001]) and then reached a plateau. Conclusions After pulmonary endarterectomy, the hemodynamic recovery occurred immediately, and the patients’ exercise capacity improved during the year. The 6-minute walk test was a good indicator to assess the recovery of exercise capacity.