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 Wood Units (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.

Sarcoidosis-Associated Pulmonary Hypertension.

Pulmonary hypertension (PH) is a well-known complication of sarcoidosis, defined by a mean pulmonary artery pressure of ≥25 mm Hg. Since both PH and sarcoidosis are rare diseases, data on sarcoidosis-associated PH (SAPH) is retrieved mostly from small retrospective studies. Estimated prevalence of SAPH ranges from 3% in patients referred to a tertiary center up to 79% in patients awaiting lung transplant. Most patients with SAPH show advanced parenchymal disease as the underlying mechanism. However, some patients have disproportional elevated pulmonary artery pressure, and PH can occur in sarcoidosis patients without parenchymal disease. Other mechanisms such as vascular disease, pulmonary embolisms, postcapillary PH, extrinsic compression, and other sarcoidosis-related comorbidities might contribute to SAPH. The diagnosis of PH in sarcoidosis is challenging since symptoms and signs overlap. Suspicion can be raised based on symptoms or tests, such as pulmonary function tests, laboratory findings, electrocardiography, or chest CT. PH screening mainly relies on transthoracic echocardiography. Right heart catheterization should be considered on a case-by-case basis in patients with clinical suspicion of PH, taking into account clinical consequences. Treatment options are considered on patient level in a PH expert center, and might include oxygen therapy, immunosuppressive, or PH-specific therapy. However, qualitative evidence is scarce. Furthermore, in a subset of patients, interventional therapy or eventually lung transplant can be considered. SAPH is associated with high morbidity. Mortality is higher in sarcoidosis patients with PH compared with those without PH, and increases in patients with more advanced stages of sarcoidosis and/or PH.

Value of echocardiography using knowledge-based reconstruction in determining right ventricular volumes in pulmonary sarcoidosis: comparison with cardiac magnetic resonance imaging.

Right ventricular (RV) dysfunction in sarcoidosis is associated with adverse outcomes. Assessment of RV function by conventional transthoracic echocardiography (TTE) is challenging due to the complex RV geometry. Knowledge-based reconstruction (KBR) combines TTE measurements with three-dimensional coordinates to determine RV volumes. The aim of this study was to investigate the accuracy of TTE-KBR compared to the gold standard cardiac magnetic resonance imaging (CMR) in determining RV dimensions in pulmonary sarcoidosis. Pulmonary sarcoidosis patients prospectively received same-day TTE and TTE-KBR. If performed, CMR within 90 days after TTE-KBR was used as reference standard. Outcome parameters included RV end-diastolic volume (RVEDV), end-systolic volume (RVESV), stroke volume (RVSV) and ejection fraction (RVEF). 281 patients underwent same day TTE and TTE-KBR. In total, 122 patients received a CMR within 90 days of TTE and were included. TTE-KBR measured RVEDV and RVESV showed strong correlation with CMR measurements (R = 0.73, R = 0.76), while RVSV and RVEF correlated weakly (R = 0.46, R = 0.46). Bland-Altman analyses (mean bias ± 95% limits of agreement), showed good agreement for RVEDV (ΔRVEDVKBR-CMR, 5.67 ± 55.4 mL), while RVESV, RVSV and RVEF showed poor agreement (ΔRVESVKBR-CMR, 21.6 ± 34.1 mL; ΔRVSVKBR-CMR, - 16.1 ± 42.9 mL; ΔRVEFKBR-CMR, - 12.9 ± 16.4%). The image quality and time between CMR and TTE-KBR showed no impact on intermodality differences and there was no sign of a possible learning curve. TTE-KBR is convenient and shows good agreement with CMR for RVEDV. However, there is poor agreement for RVESV, RVSV and RVEF. The use of TTE-KBR does not seem to provide additional value in the determination of RV dimensions in pulmonary sarcoidosis patients.

Pulmonary Hypertension Associated Genetic Variants in Sarcoidosis Associated Pulmonary Hypertension.

BACKGROUND: Pulmonary hypertension (PH) is a severe complication of sarcoidosis in a minority of patients. Several genetic defects are known to cause hereditary or sporadic PH, but whether variants in PH-associated genes are also involved in sarcoidosis-associated PH (SAPH) is unknown. METHODS: 40 patients with SAPH were individually matched to 40 sarcoidosis patients without PH (SA). Whole exome sequencing was performed to identify rare genetic variants in a diagnostic PH gene panel of 13 genes. Additionally, an exploratory analysis was performed to search for other genes of interest. From 572 genes biologically involved in PH pathways, genes were selected in which at least 15% of the SAPH patients and no more than 5% of patients without PH carried a rare variant. RESULTS: In the diagnostic PH gene panel, 20 different rare variants, of which 18 cause an amino-acid substitution, were detected in 23 patients: 14 SAPH patients carried a variant, as compared to 5 SA patients without PH (p = 0.018). Most variants were of yet unknown significance. The exploratory approach yielded five genes of interest. First, the NOTCH3 gene that was previously linked to PH, and furthermore PDE6B, GUCY2F, COL5A1, and MMP21. CONCLUSIONS: The increased frequency of variants in PH genes in SAPH suggests a mechanism whereby the presence of such a genetic variant in a patient may increase risk for the development of PH in the context of pulmonary sarcoidosis. Replication and studies into the functionality of the variants are required for further understanding the pathogenesis of SAPH.

Echocardiographic estimate of pulmonary artery pressure in sarcoidosis patients - real world data from a multi-national study.

INTRODUCTION: Echocardiographic measurement of the right ventricular systolic pressure (RVSP) is commonly used for estimating systolic pulmonary artery pressure (PASP) measured during right heart catheterization (RHC) in patients suspected for pulmonary hypertension (PH). Generally, there seems to be a strong correlation. However, this has been reported as less robust in sarcoidosis. We aim to investigate the correlation between RVSP and RHC measurements using real world data and analyzed factors influencing the relationship between RVSP and PASP in sarcoidosis. METHODS & RESULTS: Data of patients with and without sarcoidosis associated PH who had both a measurable echocardiographic RVSP and invasive PASP were collected from the RESAPH registry, PULSAR study and Cincinnati Sarcoidosis Clinic database (n=173, 60.1% female, mean age 56.0±9.5 years). Among them, 124 had PH confirmed by RHC. There was a strong correlation between RVSP and PASP (r=0.640). This correlation was significant in both male and female, white or non-white, forced vital capacity (FVC) >60%, and presence of fibrosis (p<0.001). However, it was less robust in patients with FVC of 50% or less. RVSP was considered inaccurate if the difference with PASP was > 10mmHg. Inaccurate echocardiographic estimation of the invasive PASP occurred in 50.8%, with overestimation mostly in patients without PH, and underestimation in patients with severe PH. An RVSP>50mmHg was associated with worse survival. CONCLUSIONS: In this real world multicenter cohort of sarcoidosis patients, we found a significant correlation between RVSP as determined by echocardiography and invasive PASP. Over- or underestimation of PASP occurred frequently. Therefore, echocardiographic RVSP measurement alone to screen for PH in sarcoidosis should be used with caution.