Congenital Heart Interventions

Progression in Fontan conduit stenosis and hemodynamic impact during childhood and adolescence. Patel ND, Friedman C, Herrington C, Wood JC, Cheng AL. J Thorac Cardiovasc Surg. 2021 Aug;162(2):372-380.e2. doi: 10.1016/j.jtcvs.2020.09.140. Epub 2020 Oct 29.PMID: 33220959   Take Home Points: Patients with Fontan circulation and an extra-cardiac conduit experience decrease in the cross-sectional area (CSA) as early as 6 months post Fontan. Longer term, almost all patients develop some decrease in Fontan CSA. Proactive surveillance can help identify patients with narrowing of the Fontan conduit and they can be referred for intervention to restore the Fontan conduit size. Commentary from Dr. Konstantin Averin (Edmonton), catheterization section editor of Pediatric Cardiology Journal Watch: Palliation for patients with single ventricle physiology culminates in a connection of the inferior vena cava (IVC) to the pulmonary arteries. The method of this connection has evolved over time but at many centers currently involves the use of Goretex conduit, typically 18 or 20mm diameter. The ideal diameter of this connection is unknown but it would be logical to think that it should approximate the size of the IVC. The authors sought to characterize changes to Fontan conduit size over time and determine if a decrease in cross sectional area (CSA) affects cardiac output, pulmonary artery growth or exercise capacity.   From January 2013 to October 2019; 165 patients with Fontan circulation underwent either cardiac catheterization (87) or cardiac MRI (93). After excluding those with a lateral tunnel Fontan and duplicate studies, 75 cardiac catheterizations and 83 cardiac MRI were included for analysis – with a mean time from Fontan to MRI/cath of 9.5 ± 3.9 years. The minimum Fontan CSA decreased by a median of 33% (24%, 40%) during a mean follow up of 9.6 years (Figure 1). Strikingly, even at less than 1-year post-Fontan the median decrease was already 33% (25%, 41%). The size of the conduit at implant did not impact the percentage decrease in CSA. Fontan CSA was not associated with median Nakata index (ρ = 0.09, P = 0.29) or cardiac index (ρ = -0.003, P = 0.013); but was moderately related with % predicted oxygen consumption (ρ = 0.31, p = 0.013).   Many additional analyses were performed and reported but the headline finding from this study is that Fontan CSA area decreases as early as 6 months post-Fontan. Luckily, children who are 3-5 years old have smaller IVC’s and can probably tolerate narrowing of the Fontan conduit. Looking at Figure 1, it also becomes clear that almost all patients who undergo an extra cardiac conduit Fontan will have some degree of conduit narrowing when the conduit is imaged. These findings should reinforce the importance of proactive Fontan imaging with some combination of cardiac MRI or cardiac catheterization. This would allow for the identification of patients who have a significant mismatch between their IVC and Fontan conduit and allow for intervention on the Fontan conduit to maximize the Fontan CSA and minimize resistance to venous return. It will be important to assess whether this approach will help to prolong Fontan longevity and minimize the incidence of Fontan failure.     Figure 1: A total of 158 patients underwent imaging of the Fontan conduit via MRI (n = 83) or cardiac catheterization (n = 75). There is a significant decrease in the minimum Fontan CSA that starts after the Fontan operation. MRI, Magnetic resonance imaging; CSA, cross-sectional area   

Percutaneous Common Carotid Artery Access for Cardiac Interventions in Infants Does Not Acutely Change Cerebral Perfusion. Lahiri S, Qureshi AM, Justino H, Mossad EB. Pediatr Cardiol. 2022 Jan;43(1):104-109. doi: 10.1007/s00246-021-02697-9. Epub 2021 Aug 7. PMID: 34363498   Take Home Points: NIRS can be used to assess regional cerebral oxygen saturation in patients receiving common carotid artery (CCA) vascular access in the congenital cardiac catheterization laboratory. There was no change in NIRS with CCA access during cardiac catheterization in neonates and infants. Further prospective studies are needed to understand trends of lower regional cerebral oxygen saturation with certain procedure lengths and cardiac physiologies. Commentary from Dr. Arash Salavitabar (Columbus, OH, USA), section editor of Congenital Heart Disease Interventions Journal Watch: The authors address the important and unknown impact of percutaneous common carotid artery (CCA) vascular access and cerebral perfusion in the cardiac catheterization laboratory using Near-Infrared Spectroscopy (NIRS) to assess regional cerebral oxygen saturation (rSO2). This was a single-center retrospective chart review at a large tertiary care center over a 10 year period. All patients who had ipsilateral cerebral NIRS monitored on the side of CCA access were included.   The typical institutional practice described by the authors was to place one NIRS probe on each side of the patient’s forehead if cardiac catheterization was being performed via CCA. NIRS data were collected continuously from 15 minutes prior until 15 minutes after the end of the procedure, and the mean NIRS were compared between pre-vascular access, during access, and following sheath removal. The primary outcome measure was the change in NIRS with CCA access. The secondary outcome measure was the area under the curve for rSO2 ≤ 45%, which was based off of thresholds of prior studies associated with neurodevelopmental outcomes. The value of “Integrated rSO2” (=minutes × (desaturation values ≤ 45%)) was chosen as a marker of neurodevelopmental outcomes, which was chosen over total duration of rSO2 ≤45% in order to better indicate the extent of desaturation below the threshold value.   This study included 21 patients. The median patient age was 23 days (IQR 7,79) and weight was 3.3 kg (IQR 2.8,2.9). The median sheath size was 4F (3.3–5F) and duration of the procedure was 1 h 48 min (range 22 min to 4 h). There was no significant difference found in mean NIRS before, during, or after the CCA catheterizations. Integrated rSO2 ≤ 45% was grouped into 3 groups (0 min, 0.1–39 min, ≥40 min). There were no significant differences in total integrated rSO2 ≤ 45%, total procedure duration, minimum integrated rSO2 ≤ 45%, average rSO2, or minimum rSO2 between the 3 groups. Of clinical importance, Group III had the longest procedure duration and lower average rSO2, of which one patient had an extremely low NIRS noted by the authors. When analyzing patients who had bilateral NIRS documented, neither integrated rSO2≤ 45% nor NIRS was significantly different between two sides during the procedure. Three total patients had significantly elevated integrated rSO2 ≤ 45%, two of which were thought to be secondary to ductal constriction, rather than CCA access.     This paper addresses an impactful topic that has not yet been fully explored. The authors provide important baseline findings that show that cerebral perfusion is not significantly or adversely affected in patients who receive CCA in the congenital cardiac catheterization laboratory. It is important to note that this study included a small sample size and was limited by retrospective data collection and analysis. To fully understand the trends seen in a small number of patients, it will be important to perform a prospective study evaluating CCA and markers of cerebral perfusion in a more rigorous way. Nonetheless, this data is an important first step to understanding the impact of this form of vascular access in what is often a fragile population.