Renal failure as first manifestation of familial sarcoidosis.

only a small group of patients willing to consent to two prolonged right heart catheterisation procedures 6 months apart. Nevertheless, this group was relatively homogeneous, with NYHA class III disease and high P̄pa at presentation. Our results cannot be generalised, however, to other related PAH disease states, such as congenital heart disease or chronic pulmonary thromboembolism. Thirdly, our already lengthy study protocols (each lasting 2–3 h) did not allow time for cardiac output measurements at baseline and after each vasoactive drug, on each occasion of study. It is known from previous work that bosentan reduces pulmonary vascular resistance and increases cardiac output in PAH patients such as ours [10]; given this, the ability of ACh to produce greater vasodilatation after, compared with before, bosentan treatment clearly indicates improved endothelium-dependent dilator capacity after bosentan therapy. Finally, although IVUS measurements from control subjects were available to compare with the PAH patients, we did not perform (the relatively lengthy protocol for) pulmonary vascular reactivity studies in the healthy control subjects, to minimise risk to these volunteers.