Is there a hope in pharmacological treatment of thromboembolic pulmonary hypertension?

Chronic thromboembolic pulmonary hypertension that used to be treated with anticoagulation therapy only had serious prognosis. The five-year survival of patients with the mean pulmonary artery pressure above 50 mm Hg was just 10%. The introduction of pulmonary endarterectomy in clinical practice represented a significant improvement in patient prognosis. However, about 1/3 of patients have distal lesions and are thus not eligible for surgery. In addition, the surgery is not indicated in a number of patients due to serious co-morbidities. Even though milder, pulmonary hypertension persists in 10-15% of post-surgery patients. About 50% of patients are candidates for pharmacological vasodilatation treatment. To summarize the current knowledge of pharmacotherapy in these patients, the open-label studies provide limited information as they were conducted on small patient samples and were not blinded. The only large prospective blinded study of treatment with bosentan, BENEFiT, confirmed that there is a reduction of pulmonary vascular resistance after 16 weeks of treatment. However, bosentan did not affect exercise tolerance. Furthermore, the study follow up was 16 weeks only. Observational data from the British national registry of chronic thromboembolic pulmonary hypertension suggest that up to 72-77% of patients are pharmacotherapy candidates. Furthermore, the British registry data show significantly better survival of patients treated recently, in 2003 and beyond (treated mostly with bosentan or sildenafil), and thus provide an important indirect evidence of the positive effect of pharmacotherapy, particularly in comparison to our data from 1982 that show the natural course of chronic thromboembolic pulmonary hypertension before the introduction of pulmonary endarterectomy in clinical practice and before modern pharmacotherapy.

Keywords: chronic thromboembolic pulmonary hypertension; pharmacotherapy; pulmonary endarterectomy