Bosentan induces clinical and hemodynamic improvement in candidates for right-sided heart bypass surgery

Objective: To investigate the efficacy of bosentan in patients with single-ventricle physiology who were unable to undergo right-sided heart bypass surgery because of high pulmonary vascular resistance and pulmonary artery pressure. Methods: Eight patients with single-ventricle physiology (2 male and 6 female; aged 7 months to 5 years, median 1 year) were enrolled. Prior surgical interventions included pulmonary artery banding in 4 patients, Blalock-Taussig shunt operation in 2 patients, and bidirectional Glenn operation in 5 patients. Right-sided heart bypass surgery was contraindicated for all patients because of high pulmonary vascular resistance and pulmonary artery pressure. Results: Bosentan therapy successfully reduced pulmonary artery pressure and pulmonary vascular resistance in all patients. Mean pulmonary artery pressure at baseline and after bosentan therapy was 21.1 ± 7.2 mm Hg and 11.9 ± 4.1 mm Hg, respectively (P < .01). Mean pulmonary vascular resistance index at baseline and after bosentan therapy was 5.7 ± 3.3 U/m² and 1.3 ± 0.4 U/m², respectively (P < .01). Mean pulmonary vascular resistance/systemic vascular resistance at baseline and after bosentan therapy was 0.25 ± 0.11 and 0.07 ± 0.03, respectively (P < .01). All patients had improved clinical symptoms and underwent successful Fontan operations. Conclusion: Bosentan induces mid-term clinical and hemodynamic improvement in patients with single-ventricle physiology and elevated pulmonary vascular resistance and pulmonary artery pressure. Bosentan therapy may increase the surgical options and improve outcomes in candidates for right-sided heart bypass surgery.