Routine Cardiac Catheterization Prior to Fontan Operation: Is It a Necessity?

Prior to the Fontan procedure, patients with single ventricle physiology with Glenn shunt are typically referred for cardiac catheterization to assess hemodynamics and potentially provide interventional measures. Currently, echocardiography provides detailed information which together with other non-invasive imaging such as CT scan and MRI may obviate the need for routine cardiac catheterization prior to the Fontan procedure. In this study, we examine the findings in cardiac catheterization in this population to determine: (a) the accuracy of echocardiography in providing adequate information prior to the Fontan procedure, particularly in identifying those in need of per-catheter intervention, and (b) the percentage of patients requiring interventional procedures during cardiac catheterization. We performed a retrospective chart review of echocardiographic and cardiac catheterization data for patients who underwent pre-Fontan cardiac catheterization at our center in the period from 02/01/2008 to 02/28/2017. We aimed to re-examine the necessity of routine cardiac catheterization in all single ventricle patients. This was performed through examining pre-catheterization echocardiography reports and comparing them to findings of the subsequent cardiac catheterization reports. Echocardiography reports were evaluated for accuracy in identifying significant anatomical or hemodynamic findings, which may impact success of Fontan procedure as well as the ability of echocardiography to predict findings important to know prior to the Fontan procedure. In this cohort of 40 children, 3 patients were found to have significant hemodynamic findings through cardiac catheterization which were not previously known by echocardiography. In addition, 28 out of 40 patients (70%) required interventional procedures to address significant abnormalities (systemic to pulmonary arterial collaterals, pulmonary artery stenosis, aortic arch stenosis, etc.). All cases of aortic arch stenosis were detected by echocardiography, however, all patients who required systemic to pulmonary arterial or left SVC embolization were not detected by echocardiography. Furthermore, echocardiography did not detect the need for branch pulmonary artery stenosis in 50% of cases. Cardiac catheterization appears to be an essential part of patient assessment prior to Fontan completion in patients with single ventricle physiology. This current practice may change in the future if a non-invasive screening tool is found to have high positive and negative predictive values in identifying the subset of patients who require potential intervention in pre-Fontan cardiac catheterization.