Pulmonary artery compliance in different forms of pulmonary hypertension

Amber McCormick, LSU Health Sciences Center - New Orleans
Amita Krishnan, LSU Health Sciences Center - New Orleans
David Badesch, University of Colorado Denver
Raymond L. Benza, The Ohio State University Wexner Medical Center
Todd M. Bull, University of Colorado Denver
Teresa De Marco, University of California, San Francisco
Jeremy Feldman, Arizona Pulmonary Specialists
Anna R. Hemnes, Vanderbilt University
Russel Hirsch, Cincinnati Children's Hospital Medical Center
Evelyn Horn, Weill Cornell Medicine
Jaime Kennedy, Inova Heart and Vascular Institute
Stephen C. Mathai, Johns Hopkins University
Wesley McConnell, Kentuckiana Pulmonary Associates
Steven C. Pugliese, University of Pennsylvania
Jeffrey S. Sager, Cottage Pulmonary Hypertension Center
Oksana A. Shlobin, Inova Fairfax Hospital
Marc A. Simon, University of California, San Francisco
Matthew R. Lammi, LSU Health Sciences Center - New Orleans


Objective Pulmonary artery compliance (PAC), estimated as stroke volume (SV) divided by pulmonary artery pulse pressure (PP), may be a predictor of survival in pulmonary arterial hypertension (PAH). Resistance-compliance (RC) time, the product of PAC and pulmonary vascular resistance, is reported to be a physiological constant. We investigated if differences in PAC and RC time exist between pulmonary hypertension (PH) subgroups and examined whether PAC is an independent predictor of transplant-free survival in PAH. Methods This was a retrospective analysis of adult PAH (n=532) and chronic thromboembolic PH (CTEPH, n=84) patients enrolled in the US Pulmonary Hypertension Association Registry from 2015 to 2019. PAC and RC time were compared between PH subgroups (connective tissue disease-PAH (CTD-PAH), idiopathic/heritable-PAH (i/h-PAH), drug/toxin-PAH (d/t-PAH)). Cox proportional hazards models were constructed for transplant-free survival, adjusting for REVEAL 2.0 risk score. Results There were no differences in estimated PAC between PAH subgroups, nor between PAH and CTEPH. RC time was shorter in CTEPH compared with PAH (median 0.55 (IQR 0.45-0.64) vs 0.62 (0.52-0.73) s, p<0.0001). RC time was shortest in CTD-PAH when compared with i/h-PAH and d/t-PAH ((0.59±0.18) vs (0.65±0.20) vs (0.73±0.25) s, p=0.0001). PAC was associated with transplant-free survival (HR 0.72, 95% CI 0.55 to 0.94, p=0.02) but was not an independent predictor of outcome after adjustment for REVEAL 2.0 score. Conclusion PAC was similar between PH groups and was not an independent predictor of transplant-free survival in PAH. RC time was different between PH subgroups, challenging RC time constancy.