Histological Changes of Pulmonary Arteries Treated by Balloon Pulmonary Angioplasty in a Patient With Chronic Thromboembolic Pulmonary Hypertension

A 41-year-old man was referred to our hospital for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH). On admission, he was in World Health Organization functional class III. Right heart catheterization demonstrated that pulmonary arterial pressure (systolic/diastolic/mean) was 140/42/71 mm Hg, cardiac index was 1.6 L/min/m2 and pulmonary vascular resistance was 1663 dyn ·s·cm–5. The patient had severe pulmonary hypertension and was considered inoperable because of peripheral organized thrombi and coexisting seminoma; therefore, balloon pulmonary angioplasty (BPA) was performed. After BPA, pulmonary angiography showed improvement of pulmonary arterial flow (Figure 1A). Pulmonary arterial pressure was 108/42/67 mm Hg and cardiac index was 2.5 L/min/m2 when he returned to the cardiac care unit after BPA. His condition temporarily improved; however, 2 hours later, it deteriorated because of reperfusion pulmonary injury and gastrointestinal bleeding. He required mechanical ventilation and percutaneous cardiopulmonary support. To improve hemodynamics, another session of BPA was tried 9 days later (Figures 2A and 3A) and pulmonary arterial pressure seemed to improve to 83/48/58 mm Hg. However, he died from right heart failure on day 26 after BPA despite intensive care.Figure 1. Representative images of pulmonary angiography and histology of pulmonary arteries of the upper lobe of the right lung. A , Angiographic images before (a) and after (b) BPA. A web lesion of the right pulmonary artery (arrow) was treated by BPA. Angiography after BPA showed a dilated vessel and increased flow in the distal arteries. Arrows indicate the areas where specimen for B was obtained. B , Histology of a pulmonary artery treated by BPA (arrow in A ). This lesion was treated by BPA at the initial session and second session (26 and 17 days before death). (a) Hematoxylin–eosin stain, low magnification. A large …