Pulmonary hypertension in systemic sclerosis: different phenotypes

Abstract

Pulmonary hypertension (PH) is a frequent and severe complication of systemic sclerosis (SSc). PH in SSc is highly heterogeneous because of the various clinical phenotypes of SSc itself and because the mechanisms of PH can vary from one patient to another. PH in SSc may be due to vasculopathy of the small pulmonary arteries (group 1; pulmonary arterial hypertension), interstitial lung disease (group 3; PH due to lung disease or chronic hypoxia) or myocardial fibrosis leading to left ventricular systolic or diastolic dysfunction (group 2; PH due to chronic left-heart disease). Pulmonary veno-occlusive disease is not uncommon in SSc and may also cause PH in some patients (group 1'). There is a high prevalence of each of these conditions in SSc and, as such, it may be difficult to determine the dominant cause of PH in a particular patient. However, careful phenotyping of PH in SSc is important as the therapy required for each of these underlying conditions is very different. In this review, we will decipher the different phenotypes of SSc-PH.

FIGURE 1

Clinical phenotypes of pulmonary hypertension (PH) in systemic sclerosis (SSc). PH may be heterogenous in SSc and many mechanisms can combine to produce a number of possible clinical phenotypes. A given patient can be placed somewhere on this three-axis graph with the x-axis ranging from post-capillary PH to severe pre-capillary PH, the y-axis ranging from no interstitial lung disease (ILD) to extensive ILD and the z-axis ranging from limited cutaneous SSc to diffuse cutaneous SSc. It is useful to consider possible pulmonary veno-occlusive disease (PVOD)-like conditions in patients with severe pre-capillary PH.