Initial experience with bosentan therapy in patients considered ineligible for heart transplantation because of severe pulmonary hypertension

Background: Pre-operative elevated pulmonary vascular resistance (PVR) has been associated with increased right ventricular failure and mortality after heart transplantation. The aim of this study was to assess the efficacy of bosentan, an oral endothelin-receptor antagonist, to reduce PVR in patients considered ineligible for heart transplantation because of severe pulmonary hypertension. Methods: Seven patients with end-stage congestive heart failure and considered ineligible for heart transplantation because of severe pulmonary hypertension (PVR > 2.5 Wood units after nitroprusside infusion) were included in the study. They received bosentan 62.5 mg b.i.d. for four wk and 125 mg b.i.d. thereafter. Right heart catheterization was repeated after six wk of therapy. Results: After six wk of bosentan therapy, there was a significant decrease in PVR (6.0 +/- 2 vs. 3.8 +/- 2 Wood units, before vs. after bosentan; p=0.02), in PVR during nitroprusside infusion (3.3 +/- 1 vs. 2.1 +/- 1 Wood units, before vs. after bosentan; p=0.02) and in diastolic pulmonary artery pressure (33 +/- 7 vs. 23 +/- 7 mmHg, before vs. after bosentan; p=0.04). No significant adverse events were observed. After bosentan therapy, five patients had PVR <= 2.5 Wood units. They were included in the waiting list and all five had a successful heart transplantation, although two of them required bosentan after surgery. Conclusions: In patients considered ineligible for heart transplantation because of high PVR, bosentan therapy significantly reduced PVR. These data suggest that therapy with endothelin-receptor blockers might be useful to identify a subgroup of patients with high PVR who can benefit from heart transplantation.