Efficacy and Safety of Bosentan in Adults with Simple and Complex Eisenmenger's Syndrome

Background.  Eisenmenger's syndrome (ES) is associated with decreased longevity and reduced functional capacity. Targeted pharmacologic therapies improve functional capacity and survival in these patients. We sought to compare the response of patients with simple vs. complex ES following initiation of bosentan. Methods.  ES patients with a history of bosentan use were identified by chart review. Simple ES was defined as ES associated with atrial septal defect, ventricular septal defect, or patent ductus arteriosus. Complex ES consisted of patients with truncus arteriosus and single ventricle congenital heart disease. Six-minute walking distance (6MWD), maximal oxygen consumption (VO2 max), brain natriuretic peptide (BNP), and resting oxygen saturation were compared between simple and complex ES patients before and after bosentan treatment. Results.  Twenty-four patients were included (11 simple, 13 complex). Resting oxygen saturation, 6MWD, VO2 max, and BNP were not significantly different between the two groups prior to bosentan initiation. Ten patients received bosentan monotherapy, and bosentan was used in combination with sildenafil in 13 (five simple, eight complex). One patient received bosentan with iloprost. Mean duration of therapy was 38 ± 14 months in the simple group and 40 ± 8.1 months in the complex group (P= NS). Posttreatment, 6MWD increased from 274 ± 135 m to 326 ± 106 m in simple ES patients (P= .32). 6MWD in patients with complex ES increased from 332 ± 51 m to 364 ± 109 (P= .028). VO2 max improved from 13.4 ± 3.8 to 17 ± 6 (P= .54) in the simple group, while VO2 max in the complex group improved from 12.7 ± 2.3 to 15.5 ± 2.2 (P= .17). There was minimal change in BNP or resting oxygen saturation between the groups. Conclusions.  Treatment with bosentan is both safe and effective in patients with both simple and complex forms of ES.