Utilizing optical coherence tomography to explore pulmonary arteries and pulmonary vascular disease in Fontan patients

Background: The Fontan procedure is the palliative intervention of choice for patients with single ventricle physiology. Pulmonary vascular disease (PVD) is a major contributor to Fontan circulatory failure. Our study utilized optical coherence tomography (OCT) imagery in pulmonary arteries to better characterize PVD in Fontan patients. Methods: In a prospective pilot study, OCT images were acquired during cardiac catheterization in a distal left pulmonary artery (PA) branch (A10). The PA intima-media ratio and wall-vessel ratio (i.e., difference between the external elastic membrane area and the luminal area divided by the external elastic membrane area) were measured off-line. Results: A total of 9 Fontan patients (5 women), median age of 23.0 (21.0,38.0) years, were included. All patients exhibited an intima-to-media ratio above 1.0. The ratio exceeded 2.8 in patients with high pulmonary vascular resistance. No difference is observed between patients for the wall-vessel ratio. No relation between time of completion of Fontan and intima-media ratio is identified. Conclusion: OCT shows promise in evaluating PVD in patients with Fontan palliation. PA remodeling is characterized by intimal hyperplasia with medial regression. Further studies are required to determine the role of OCT in guiding treatment decisions and assessing therapeutic responses.