Background: Pulmonary artery pressure (PAP) is reduced dramatically after pulmonary thromboendarterectomy in patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, it is unclear whether pulmonary artery compliance increases in conjunction with the reduction in PAP. Pulmonary artery compliance may affect right ventricular afterload and prognosis.
Methods and results: In 33 patients with CTEPH (9 men, 22-76 years), changes in the tricuspid regurgitation pressure gradient (TRPG) and the acceleration time (ACT) of pulmonary artery flow (a surrogate parameter of pulmonary artery compliance) were examined before and after pulmonary thromboendarterectomy using echocardiography to clarify factors affecting the changes. At 6 months, both TRPG and ACT normalized (<or=30 mmHg, >or=100 ms, respectively) in 25 patients (group A) but not in 8 (group B). In group B, there were 5 with normal TRPG and shortened ACT at 6 months that normalized at 17+/-3 months. Group A patients showed shorter disease period and shorter period without anticoagulation than group B patients (p=0.04, 0.02 respectively). All patients in group A had the proximal type, and 2 patients of group B had the distal type (p=0.05). Clinical improvement was more remarkable in group A.
Conclusions: The recovery of PAP and the ACT of pulmonary artery flow was not always concordant after pulmonary thromboendarterectomy, suggesting a presence of a time lag in the recovery between pressure and compliance in some patients. A long period of CTEPH, a long period without anticoagulation and the distal embolism type may be predictive factors of an unfavorable operative result with reduced pulmonary artery compliance, and hence poor recovery of clinical performance.