Clinical Phenotypes of Sarcoidosis-Associated Pulmonary Hypertension

Background and objective Pulmonary hypertension (PH) is a known complication of pulmonary sarcoidosis and its aetiology is unclear. Different pathophysiological mechanisms in sarcoidosis-associated pulmonary hypertension (SAPH) are known. Clinical phenotyping can aid clinicians in choosing the optimal treatment strategy. This study aimed to describe clinical phenotypes of SAPH and their characteristics. Methods A retrospective cohort study was performed on all SAPH patients at a tertiary referral centre. All patients were extensively analysed and discussed case by case in a multidisciplinary expert team to determine the most likely pathophysiological mechanism of PH. Patients were then classified into conceptual clinical phenotypes. Results Forty (40) patients with SAPH were identified between 2010 and 2019. Three (3) patients were classified as the postcapillary phenotype. Of the remaining 37 patients with precapillary PH, six were classified as ‘compression of pulmonary vasculature’, 29 as ‘parenchymal’, one as ‘suspected vasculopathy’, and one as ‘chronic pulmonary emboli’ phenotypes. Of the patients with compression of pulmonary vasculature, four showed compression by fibrotic disease and two by active sarcoidosis-based disease. Within the parenchymal phenotype, 20 patients (69%) showed pulmonary vascular resistance >3.0 WU and had significantly lower diffusing capacity of the lung for carbon monoxide compared with the nine patients (31%) with pulmonary vascular resistance ≤3.0 WU. Conclusion SAPH had multiple pathophysiological mechanisms and clinical phenotypes in this retrospective study. Further studies are necessary to examine how these phenotypes can affect appropriate treatment and prognosis.