Multiple coronary artery microfistulae are common and progress in adult patients late after Fontan operation

Abstract

Abstract Background Coronary angiograms of adult Fontan patients sometimes show the abnormal multiple coronary artery microfistulae (mCAFs) that drain directly into the ventricular chamber. They look like coronary artery fistulae or Thebesian vein. Angiographically detectable mCAFs are a rare finding sometimes associated with myocardial ischemia due to coronary steal and volume overload of ventricles in non-CHD adults. However, there are limited data concerning these mCAFs in the setting of CHD patients. Purpose The aim of this study is to demonstrate presence, character, and changes with growth of mCAFs in adult patients late after Fontan operation. Methods This study is single-center retrospective review of adults (16 years old or older) with Fontan circulation patients who had undergone cardiac catheterization for routine Fontan surveillance between 2009-2022. We assessed the presence of angiographically detectable mCAFs from ascending aortography. After identification of the characteristic cases, we examined the ventricular morphology, the portion of drainage, and compared with previous findings of angiograms. SaO2, EF of main ventricle, CVP, EDP of main ventricle, BNP, and use of pulmonary vasodilators were compared between mCAFs(+) group and mCAFs(-) group. We also reviewed clinical manifestation and findings of exercise stress ECG of the patients. Pulmonary atresia with intact ventricular septum was excluded because abnormal coronary arterial communications have been well documented in this condition. Results Among 90 Fontan patients who had undergone catheterization, significant mCAFs were observed in a total of 18 cases (20%). There were 10 right-dominant single ventricle, 4 left-dominant single ventricle, and 4 unbalanced two ventricles. In all cases, including left-dominant single ventricle, all fistulae drained into right ventricle cavity, never into left ventricle. The patients who underwent serial catheterizations demonstrated that the dilation and tortuosity of fistulae progressed over time. The comparison of two groups showed SaO2 was low, BNP and CVP was high significantly in mCAFs(+) group. There were no significant differences in other factors including age at catheterization and the use of pulmonary vasodilators. Among 10 patients who had underwent exercise stress ECG, only 1 patient showed ST segment depression. None had clinical history of chest pain, and arrhythmia, and ischemic event. Conclusions MCAFs are common and progress in adult patients late after Fontan operation. Although the clinical significance and etiology of these findings remains uncertain, particular attention should be given to subclinical Fontan failure caused by hhigh CVP, volume overload, and myocardial ischemia for the future of adult Fontan patients who have prominent mCAFs.