Objective: To investigate the long-term effect of bosentan on outcome in patients after Fontan operation.
Methods: Patients after Fontan surgery were randomly divided into bosentan group (B, n = 16) and control group (C, n = 23). Bosentan was applied within 7 days after Fontan surgery as follows: at the first month, 7.8125 mg Bid for patients with body weight ≤ 10 kg; 15.625 mg Bid for patients with body weight between 10-20 kg; 31.25 mg Bid for patients with body weight 20-30 kg and 62.5 mg Bid for patients with body weight > 30 kg. At the second month, the bosentan dose was doubled and Bosentan therapy was continued for more than 1 year. Group C didn't take drugs affecting pulmonary artery pressure. All patients were followed up for 2 years and incidence of mortality, protein losing enteropathy, pulmonary arteriovenous fistulae, 6-minute walk test, heart function were compared between the two groups.
Results: After 2 years, mortality tended to be lower in group B compared to group C [6.25% (1/16) vs. 21.8% (5/23), P > 0.05]. Incidence of pulmonary arteriovenous fistulae and protein losing enteropathy were significantly lower in group B than in group C (6.25% vs. 34.78%, P = 0.01;6.25% vs. 39.13%, P = 0.02, respectively) . The results of 6-minute walk test[ (485 ± 44) m vs. (302 ± 183) m] and heart function in group B (3 NYHA III/IV patients in group B vs. 14 NYHA III/IV patients in group C, all P < 0.05) were all better than group C. The concentrations of vasoactive factors such as brain natriuretic peptide (BNP, 279.07 ± 128.17 vs. 457.67 ± 221.30), endothelin (ET, 3.30 ± 0.61 vs. 4.98 ± 1.24) and thromboxane (TXA2, 97.2 ± 24.0 vs. 163.22 ± 24.4) were also significantly lower in group B than in group C (all P < 0.05). Prostacyclin (PGI2) level and incidence of arrhythmias were similar between the two groups. There was no thrombotic event in both groups during follow up.
Conclusion: Bosentan trerapy in patients post Fontan operation could reduce the incidence of pulmonary arteriovenous fistulae and protein losing enteropathy and improve heart function.