Sarcoidosis-associated Pulmonary Hypertension: Pathophysiology, Diagnosis, and Treatment

Abstract

Clinicians in pulmonary medicine frequently confront the challenge of screening, diagnosis and management of pulmonary hypertension (PH) in sarcoidosis patients who present with unexplained dyspnea. Sarcoidosis associated pulmonary hypertension (SAPH) is most prevalent in patients with pulmonary fibrosis, though it can be independent of airflow obstruction or restriction. SAPH independently associates with significantly increased mortality and decreased functional capacity, outcomes which can be mitigated by early detection and focused treatment. In this review, we discuss the pathophysiology of SAPH, which may resemble pulmonary arterial hypertension as well as secondary causes of PH. We offer a screening algorithm for SAPH, and advocate for detailed assessment of the cause of PH in each patient prior to choice of an individualized treatment plan. We note that treatment of sarcoidosis via immune suppression is typically insufficient to adequately treat SAPH. We discuss secondary causes of SAPH such as left heart disease, sleep disordered breathing, and thromboembolic disease, and the evidence for use of PH-specific therapy in select cases of SAPH. Management of SAPH by clinicians experienced in PH, with early referral to transplantation in refractory cases is advised.

Keywords: Diagnosis; Pathophysiology; Pulmonary hypertension; Sarcoidosis; Treatment.

Figure 1. Screening and diagnostic algorithm for SAPH

In dyspneic patients with sarcoidosis at risk of PH or who exhibit signs suggestive of PH, screening echocardiography is performed, followed by right heart catheterization if echocardiography is positive or indeterminate. 6MWT 6 minute walk test, CT computed tomography, DLCO diffusing capacity of the lung for carbon monoxide, PA pulmonary artery diameter, AA Aorta diameter, FVC forced vital capacity, PASP pulmonary artery systolic pressure, RV right ventricle, SAPH sarcoidosis associated pulmonary hypertension, PH pulmonary hypertension

Figure 2. Diagnostic algorithm for pulmonary hypertension phenotype classification

Hemodynamic evaluation via RHC aids in grouping patients into pre- and post-capillary etiologies of PH. Individuals with sarcoidosis are classified as group V, and may have predominating features from any group I to IV. CTEPH chronic thromboembolic pulmonary hypertension, MPAP mean pulmonary artery pressure, PAH pulmonary arterial hypertension, PFT pulmonary function test, PH pulmonary hypertension, PVR pulmonary vascular resistance, RHC right heart catheterization.