What is PAH-SSc?

Pulmonary arterial hypertension (PAH) can be idiopathic in nature (iPAH) or can be associated with a number of conditions (Associated Pulmonary Arterial Hypertension - APAH), which together account for most other cases of PAH.  These conditions include Human immunodeficiency virus (HIV) infection, Congenital heart disease, sickle cell disease and connective tissues diseases, such as SSc and systemic lupus erythematosus (SLE).

PAH is a well-recognised complication of SLE and, more frequently of SSc and in affected patients may also occur with or without Interstitial lung disease. These two pulmonary complications are responsible for the greatest number of deaths in patients with SSc.

Why does PAH-SSc develop?

Refer to the ‘Why does PAH develop?'  section

How common is PAH-SSc?

The overall prevalence of all types of PAH is an estimated 30-50 cases per million.¹ However, the prevalence of PAH in certain at-risk groups is substantially higher and up to 16% of patients with connective tissue disease are thought to go on to develop PAH.² In SSc patients, pulmonary complications, such as PAH and interstitial lung disease, are now the leading causes of death.

What is the life expectancy in PAH-SSc?

Patients with PAH-SSc have a particularly poor prognosis compared to those with SSc without PAH (Figure 6).³

Figure 6. Comparative survival of SSc patients with and without PAH

Moreover, PAH-SSc patients have a poor prognosis compared with iPAH patients. Kawut and colleagues reported that despite similar baseline hemodynamics and treatment, patients with PAH-SSc had a worse prognosis compared with iPAH patients.  Unadjusted risk of death for the PAH-SSc patients was 2.9 compared with iPAH patients (p = 0.03), meaning that they were almost three times more likely to die (Figure 7).⁴

Figure 7. Comparative survival of iPAH patients and PAH-SSc patients

What are the symptoms of PAH-SSc?

The symptoms of PAH-SSc are essentially the same as those of iPAH.
Refer to the ‘What are the symptoms of PAH?'

In SSc patients, there is a special need for an in-depth review of the patient's medical history because reduced daily activities and exercise breathlessness may not always be the first symptom reported by patients. Sometimes SSc patients have already reduced their daily activities due to mobility problems (i.e. skin involvement and joint problems) and/or the fact that they are often older than iPAH patients.

References
1. Peacock AJ. Treatment of pulmonary hypertension. BMJ 2003; 326:835-836.
2. McGoon M, Gutterman D, Steen V et al. Screening, early detection, and diagnosis of pulmonary arterial hypertension: ACCP evidence-based clinical practice guidelines. Chest 2004; 126: 14S−34S.
3. Koh ET, Lee P, Gladman DD et al. Pulmonary hypertension in systemic sclerosis: an analysis of 17 patients. Br J Rheumatol 1996; 35:989-993
4. Kawut SM, Taichman DB, Archer-Chicko CL et al.  Hemodynamics and survival in patients with pulmonary arterial hypertension related to systemic sclerosis. Chest 2003; 123:344-350