Reverse remodeling of pulmonary arteries by high-dose prostaglandin I₂ therapy: A case report

Idiopathic pulmonary arterial hypertension (IPAH) is characterized by pulmonary vascular remodeling. We have reported that high-dose prostaglandin I₂ (PGI₂) therapy markedly improved hemodynamics in IPAH patients and that PGI₂ induced apoptosis of pulmonary artery smooth muscle cells obtained from IPAH patients. PGI₂ is thought to have reverse remodeling effects, although it has not been histologically confirmed. In a case series, we examined the reverse pulmonary vascular remodeling effects of PGI₂ in lung tissues obtained from an IPAH patient treated with high-dose PGI₂ and an IPAH patient not treated with PGI₂. Apoptotic cells were detected in small pulmonary arteries of the IPAH patient treated with high-dose PGI₂ but not in those from the IPAH patient not treated with PGI₂. Media of peripheral pulmonary arteries were thick in the IPAH patient not treated with PGI₂. On the other hand, media of peripheral pulmonary arteries were thin in the IPAH patient treated with high-dose PGI₂. The single case report suggested that high-dose PGI₂ therapy has the potential for reverse pulmonary vascular remodeling by induction of apoptosis and reduction of medial hypertrophy. Accumulation of cases is needed for the application to generalized effect of high-dose PGI₂. <Learning objective: Reverse pulmonary vascular remodeling would provide further improvement in patients with IPAH. High-dose PGI₂ therapy has the potential for reverse pulmonary vascular remodeling in patients with IPAH.>.