Systemic Sclerosis-Associated Pulmonary Arterial Hypertension: Definitions and Treatments
Clinical risk factors for SSc-PAH include long-standing disease and older age at scleroderma onset, among other factors.
SAN DIEGO — Rheumatology specialists should be aware of the clinical features of systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH), as well as the tools available to facilitate a prompt and accurate diagnosis, according to Ruth Minkin, MD, attending physician in the Department of Medicine at NewYork-Presbyterian Brooklyn Methodist Hospital and assistant professor of Clinical Medicine at Weill Cornell College of Medicine, in her presentation at the ACR/ARHP 2017 Annual Meeting.
“Why are we focusing on PAH so much in the SSc field?” Dr Minkin asked. “It is becoming a major cause of death in patients with SSc ... and is pretty much in sync with severe pulmonary fibrosis and quite significantly surpassing scleroderma renal crisis.”
Dr Minkin discussed cardiopulmonary screening recommendations for SSc-PAH, recent tools proposed for identifying patients for whom right heart catheterization is indicated, and both pharmacologic and nonpharmacologic management of the condition.
Hemodynamic Definitions of Pulmonary Hypertension
“Pulmonary hypertension is defined based on hemodynamic criteria obtained during right-sided cardiac catheterization," noted Dr Minkin, in order to distinguish between precapillary pulmonary hypertension (pulmonary arterial hypertension) and postcapillary pulmonary hypertension (pulmonary venous hypertension).
Pulmonary hypertension is categorized as a mean pulmonary arterial pressure of ≥25 mm Hg as assessed during right heart catheterization. Pulmonary capillary wedge pressure (PCWP) ≤15 mm Hg and pulmonary vascular resistance (PVR) >3 Wood units qualify pulmonary hypertension as precapillary.
Postcapillary pulmonary hypertension mainly includes pulmonary hypertension associated with left-sided heart disease. Many patients fall into this category, and there are certain hemodynamic parameters that are incorporated in the definition to make the diagnosis more precise as treatment will differ for these conditions.
“The current view of PAH is mainly focused on the right ventricle,” Dr Minkin noted. “We used to think about it as a disease of pulmonary circulation, but now I think the gears are shifted toward mainly thinking of the right ventricle as representative of disease progression and disease state.”
Pulmonary hypertension due to left-sided heart disease (LHD) is also being seen more frequently because the US population is growing older. “It is incredibly important to look for the possibility of LHD because the treatment will vary tremendously; if we initiate therapy targeted to pulmonary arterial hypertension, we may harm those patients,” Dr Minkin cautioned.