Despite currently available treatments, the prognoses of pulmonary arterial hypertension (PAH) and pulmonary capillary hemangiomatosis (PCH) remain poor. Platelet-derived growth factor and its receptor (PDGFR) have been implicated in the pathogenesis of pulmonary hypertension in PAH and PCH. Imatinib, a PDGFR antagonist, may be beneficial in the treatment of both conditions because of its potent antiproliferative effect. We report two cases that demonstrate the potential for safe and efficacious use of imatinib in PAH and PCH.
Pulmonary arterial hypertension (PAH) is a life-threatening condition characterized by a marked and sustained elevation in pulmonary artery pressure, which leads to progressive increases in pulmonary vascular resistance, right-sided heart failure, and death.1 Current therapeutic approaches mainly provide symptomatic benefit but do not substantially reduce mortality rates.2
Pulmonary capillary hemangiomatosis (PCH) is a rare cause of pulmonary hypertension characterized by an uncontrolled proliferation of pulmonary capillaries infiltrating vascular, bronchial, and interstitial pulmonary structures.3 Pharmacological treatment of PCH has had very limited success, and the prognosis remains poor.4
Platelet-derived growth factor (PDGF) and its receptor (PDGFR) have been implicated in the abnormal proliferation and migration of smooth muscle cells in the development of pulmonary hypertension in PAH and PCH.5 Imatinib is a PDGFR antagonist and may be efficacious in the treatment of PAH and PCH because of its potent antiproliferative effect.5 We review the effect of imatinib in 2 patients, one with PCH (case 1) and the other with PAH (case 2), and we discuss the potential role of imatinib in the treatment of these conditions.