Efficacy of Bosentan in Patients after Fontan Procedures：a Double-blind, Randomized Controlled Trial

Fontan surgery is a widely used palliative procedure that significantly improves the survival period of patients with complex congenital heart disease（CHD）. However, it does not decrease postoperative complication rate. Previous studies suggested that elevated mean pulmonary artery pressure（m PAP） and vascular resistance lead to decreased exercise tolerance and myocardial dysfunction. Therapy with endothelial receptor antagonists（Bosentan） has been demonstrated to improve the patients＇ prognosis. A double-blind, randomized controlled trial was performed to explore the efficacy of Bosentan in treating patients who underwent the Fontan procedure. Eligible participants were randomly divided into Bosentan group and control group. Liver function was tested at a local hospital and the results were reported to the phone inspector every month. If the results suggested abnormal liver function, treatment would be adjusted or terminated. All the participants finished the follow-up study, with no patients lost to follow-up. Unblinding after 2-year follow-up, no mortality was observed in either group. However, secondary end-points were found to be significantly different in the comparable groups. The cardiac function and 6-min walking distance in the Bosentan group were significantly superior to those in the control group（P=0.018 and P=0.027）. Bosentan could improve New York Heart Association（NYHA） functional status and improve the results of the 6-min walking test（6MWT） in Fontan patients post-surgery, and no other benefits were observed. Furthermore, a primary meta-analysis study systematically reviewed all the similar clinical trails worldwide and concluded an overall NYHA class improvement in Fontan patients who received Bosentan treatments.

A 20-Year Follow-up after the Fontan Operation in a Population with Hypoplastic Left Heart Syndrome

Background:Thromboembolic events are a cause of significant morbidity and mortality in the Fontan population.We previously reported on coagulation profile changes in a cohort of patients with hypoplastic left heart syndrome(HLHS)from Stage I through Fontan completion.In this report,we examine their clinical status,anticoagulation and incidence of thromboembolic events up to 20 years post Fontan.Methods:A retrospective chart review was conducted for twenty(20)surviving patients,from 1998 through December 2020.Patients who underwent orthotopic heart transplantation(OTx)were followed until their transplant.Patients who were found in the original study to have a factor VIII activity level>160%,were examined separately.Results:Most patients had follow-up within the last two years(2018–2020).Two patients underwent OTx and two patients died.Anticoagulation strategy was variable.Most patients were on aspirin monotherapy.There was a total of twelve thrombotic events(63.2%).These included six cerebrovascular accidents(two of which were fatal).Three out of the seven patients with elevated factor VIII activity from the original study had thromboembolic events(42.9%).Fontan complications were variable.Some degree of Fontan Associated Liver Disease was universal.Conclusions:This retrospective review of a group of single-ventricle patients post Fontan,illustrates the variability in anticoagulation therapy that exists in this population.A large proportion of patients suffered a significant thromboembolic event,including the patients with elevated factor VIII.Further investigation into the patients with elevated factor VIII may help determine whether a different antithrombotic strategy post Fontan would be beneficial.

Assessment of Contractility for Fontan Connections

This study is performed to investigate the effect of Fontan operations on cardiac contractility. Investigation of articles about the contractility in Fontan published in PubMed up to now revealed that the measurement of contractility values did not include the rudimentary ventricle. Connections between right atrium and right ventricle as well as right atrium and pulmonary artery were studied in the same group as well. In our opinion, for the single ventricular physiology, the RA-RV and RA-PA connected patients’ preload and afterload values cannot be calculated in the same group since volume of rudimentary ventricles must be considered from this point of view as well.