Screening For PAH

Pulmonary arterial hypertension (PAH), a condition of increased resistance to the flow of blood through the blood vessels of the lung, is a major cause of morbidity and mortality in scleroderma. Fortunately, if detected early, treatment of PAH can improve outcomes considerably. For this reason, current recommendations are to screen for the presence of PAH each year in individuals with scleroderma. Screening for PAH can be done using transthoracic echocardiography where an ultrasound of the heart is performed to estimate the pressures in the lung vessels. However, access to a high quality echocardiography that provides a reliable measure of pressures is not always possible. For this reason, using data collected in the Australian Scleroderma Cohort Study, ASIG has developed a screening algorithm for PAH that combines a simple blood test for NT-proBNP (a blood marker) with breathing tests (lung function) to determine an individual’s risk of having PAH. Those who screen ‘positive’ are deemed ‘at risk’ and directed to have additional tests to confirm the presence of PAH. The ASIG PAH screening algorithm is endorsed and supported internationally as a tool for PAH screening in scleroderma.

The figure here summarises the ASIG PAH screening algorithm. Those with NT-proBNP level ≥ 210 pg/mL and/or lung function tests that have abnormal parameters as specified in the figure should be referred for further diagnostic evaluation.

At present, some laboratories can test for NT-proBNP, but this test is not currently reimbursed for scleroderma PAH screening with an out-of-pocket cost of around $50-70. However, ASIG is working to have NT-proBNP listed on the Medicare Benefits Schedule for reimbursed use to screen for scleroderma PAH. Lung function tests are presently reimbursed for PAH screening in scleroderma.

References:
  1. Frost A, Badesch D, Gibbs JSR, Gopalan D, Khanna D, Manes A, et al. Diagnosis of pulmonary hypertension. European Respiratory Journal. 2018:1801904.
  2. Thakkar, V., Stevens, W. M. R., Prior, D., Moore, O. A., Byron, J., Liew, D., Patterson, K., Hissaria, P., Roddy, J., Zochling, J., Sahhar, J., Nash, P. T., Tymms, K. E., Celermajer, D. S., Gabbay, E., Youssef, P. P., Proudman, S. M., & Nikpour, M. (2012). N-terminal pro-brain natriuretic peptide in a novel screening algorithm for pulmonary arterial hypertension in systemic sclerosis: A case-control study.Arthritis Research & Therapy,14(3), [R143].https://doi.org/10.1186/ar3876
  3. Hao Y, Thakkar V, Stevens W, Morrisroe K, Prior D, Rabusa C, Youssef P, Gabbay E, Roddy J, Walker J, Zochling J, et al. A comparison of the predictive accuracy of three screening models (detect v. Esc/ers v. Asig) for pulmonary arterial hypertension in systemic sclerosis. Internal medicine journal. 2014; 44: 23-23. Doi:10.1186/s13075-015-0517-5
©2020 Australian Scleroderma Interest Group (ASIG), All rights reserved.

©2020 Australian Scleroderma Interest Group (ASIG), All rights reserved.