Exercise Induced Pulmonary Hypertension in Systemic Sclerosis and Treatment With Ambrisentan

The current literature addresses therapies for patients with resting PAH only, diagnosed by right heart catheterization. However, the World Health Organization (WHO) also recognizes and defines exercise induced pulmonary arterial hypertension (ex-PAH), which may precede the development of resting PAH. The natural progression of PAH, especially during exercise, has not been well delineated. An exercise hemodynamic study previously showed that in normal healthy subjects the mean pulmonary pressure does not exceed 30mmHg even at maximal cardiac outputs. A prior study evaluated exercise Doppler echocardiography systemic sclerosis patients with normal resting echocardiograms, finding an abnormal response which was defined as an estimated right ventricular systolic pressure greater than 40 mmHg. In the same study, 6.6% of the patients progressed to resting PAH over the followup period of 12 months. Limited data is available regarding the prevalence of ex-PAH in systemic sclerosis using right heart catheterization.