Background: Endothelin receptor antagonism has been introduced as an effective oral therapy of patients with idiopathic pulmonary arterial hypertension. In view of the pathophysiologic and histologic similarities between idiopathic pulmonary arterial hypertension and pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD), there is a rationale for treating these patients with the oral dual (ET(A)/ET(B)) endothelin receptor antagonist bosentan.
Methods: Thirty-three patients with PAH-CHD (43 +/- 14 years, 23 with Eisenmenger syndrome) were treated with bosentan for a mean of 2.1 +/- 0.5 years. Efficacy was assessed by a panel of tests, including New York Heart Association functional class, 6-minute walking distance, and echocardiographic and hemodynamic parameters.
Results: Mean 6-minute walking distance increased from 362 +/- 105 to 434 +/- 68 m (P = .001). New York Heart Association class also improved significantly (3.1 to 2.4, P = .0001). This was associated with slight trends in improvements of transcutaneous oxygen saturation (86% +/- 7% to 88% +/- 7%, P = .13) and maximum oxygen uptake (13.2 +/- 4.0 to 14.9 +/- 2.5, P = .18). Right ventricular systolic pressure measured by echocardiographic decreased from 111 +/- 32 to 106 +/- 22 mm Hg (P = .001). Bosentan treatment was well tolerated by all patients.
Conclusions: Long-term bosentan treatment in adult patients with PAH-CHD was well tolerated and improved functional status as well as exercise capacity. These findings have to be corroborated by controlled studies that are presently ongoing.