Clinical and Hemodynamic Responses to Imatinib in Pulmonary Veno-Occlusive Disease/Pulmonary Capillary Hemangiomatosis: A Retrospective Pilot Study of Five Cases and Review of the Literature

Background Pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) are rare types of pulmonary arterial hypertension with dismal prognoses; there is no established medical treatment for these conditions. Possible efficacy of imatinib against these conditions has been reported in 15 cases; however, how and in whom imatinib is effective remain unknown. Methods We retrospectively evaluated clinical data from consecutive patients with PVOD/PCH treated with imatinib at our institution. The diagnosis of PVOD/PCH was established using the following criteria: pre-capillary pulmonary hypertension; diffusion capacity of the lung for carbon monoxide < 60%; and two or more high-resolution computed tomography findings of interlobular septal thickening, centrilobular opacities, and mediastinal lymphadenopathy. The dose of pulmonary vasodilators remained unchanged during the assessment of imatinib. Results The medical records of five patients with PVOD/PCH were reviewed. The patients were aged 67 ± 13 years, their diffusion capacity of the lung for carbon monoxide was 29 ± 8%, and their mean pulmonary artery pressure was 40 ± 7 mmHg. Imatinib was administered at 50–100 mg/day; consequently, the World Health Organization functional class improved in one patient. In addition, imatinib improved the arterial oxygen partial pressure in this and another patient (these two also experienced a decreased mean pulmonary artery pressure and pulmonary vascular resistance after imatinib usage). Conclusions This study indicated that imatinib improves the clinical condition, including pulmonary hemodynamics, of some patients with PVOD/PCH. In addition, patients with a certain high-resolution computed tomography pattern or PCH-dominant vasculopathy may respond favorably to imatinib.