Sarcoidosis Associated Pulmonary Hypertension: Correlation of Cascular Morphologic Changes with Hemodynamic Data in Explanted Lungs

Abstract

Purpose Sarcoidosis associated pulmonary hypertension (PH) is classified as WHO Group V according to the 2018 WHO classification system. Previous case series have demonstrated efficacy of pulmonary vasodilators in treating severe PH in sarcoidosis. We present a series of patients with sarcoidosis associated PH and describe correlation between the pre-transplant hemodynamic data from a right heart catheterization (RHC) and vascular morphologic changes in the native explanted lungs. Methods Patients with sarcoidosis who underwent lung transplantation at Loyola University Medical Center were analyzed from 2014-2018. We collected demographic data, RHC data, NYHA functional class data, and echocardiogram. Pathology was reviewed to assess for presence and severity of fibrosis, presence or absence of granulomas in lung parenchyma and lymph nodes, and vascular morphologic changes using Heath Edwards PH classification. We evaluated PH changes in arterioles, muscular arteries of 1mm and 3mm caliber, and elastic arteries. These findings were correlated to RHC data. Results Seven patients who had a RHC prior to lung transplantation were identified and had a mean pulmonary artery pressure greater than 25 mmHg. All of the patients had well-formed granulomas except two cases that showed ill formed granulomas. 5 of 7 cases had lymph nodes involved and 5 of 7 had fibrosis. Medial hypertrophy of 1 and 3mm arteries was observed in all cases. 3 of 4 patients with severe PH (NYHA Class IV) and RV dysfunction on echocardiogram were on parenteral prostacyclin therapy at the time of transplant and had grade 3 changes in the 1 mm arteries and grade 2 changes in the 3 mm arteries. Only 2 of 7 cases showed arteriolar changes, which correlated with higher pressures. No plexiform lesions were seen in any of the patients. Conclusion In our series of sarcoidosis patients with PH who underwent lung transplant or transplantation, vascular morphologic changes at the level of the 1 mm and arterioles correlated with the presence of severe PH (NYHA Class IV) and RV dysfunction on echocardiogram. These patients lack the plexiform lesions typically seen in idiopathic pulmonary arterial hypertension. Our study may identify a subset of sarcoid patients who have significant vascular remodeling and possibly explains the recently observed favorable response to vasodilator therapy.