How is PAH-SSc diagnosed?

The early symptoms of PAH-SSc (such as dyspnea, dizziness and fatigue) are often mild and are common to many other conditions. At rest there are often no symptoms and no apparent signs of illness. As a result, diagnosis can be delayed for months or even years meaning that PAH is frequently not recognised until the disease is relatively advanced. However, the knowledge that PAH is common in patients with SSc should facilitate screening of this at-risk population and permit relatively early diagnosis. Consequently an annual echocardiogram is recommended by international Guidelines (ESC¹ and ACCP²) with subsequent referral for Right heart catheterisation for a definitive diagnosis if the echocardiogram is positive. A recommended algorithm for the use of echo as a screening tool for PAH is illustrated below (Figure 8).

Figure 8. A suggested screening protocol for the detection of PAH in SSc patients³

6-minute walk test - evaluation of exercise capacity

In patients with PAH, the 6-MWT to evaluate exercise capacity is reflective of activities of daily living⁴ and the distance a PAH patient can walk in six minutes is a critical endpoint in studies evaluating the benefit of different therapeutic options. However, although the 6-MWT is of some value in assessing functional capacity in patients with PAH-SSc, further validation is necessary in this specific patient population in terms of standardisation, presentation of results and clinically relevant changes. 

In particular the results of the 6-MWT may be confounded by SSc-specific complications, such as other cardiopulmonary disorders, musculoskeletal pain, fatigue, arthritis/tendonitis, muscle weakness and contractures.

Refer to the ‘How is PAH diagnosed?'  section for further information including Echocardiography and Right heart catherterisation

References
1. Galie N, Torbicki A, Barst R et al.  Guidelines on diagnosis and treatment of pulmonary arterial hypertension. The Task Force on Diagnosis and Treatment of Pulmonary Arterial Hypertension of the European Society of Cardiology. Eur Heart J. 2004; 25:2243-78
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. Hachulla E, Gressin V, Guillevin L et al. Early detection of pulmonary arterial hypertension in systemic sclerosis.  Arthritis Rheum 2005; 52:3792-3800.
4. Solway S, Brooks D, Lacasse Y, et al. A qualitative systematic overview of the measurement properties of functional walk tests used in the cardiorespiratory domain. Chest 2001; 119:256-70.