Cardiac Magnetic Resonance-Derived Metrics Are Predictive of Liver Fibrosis in Fontan Patients.

BACKGROUND: Liver fibrosis is a serious complication of single ventricle Fontan survivors. Its causes are of great interest, and potential solutions to halt or delay progression are needed. The purpose of this study is to investigate if prior hemodynamics and anatomy can predict liver fibrosis severity in these patients. METHODS: Twenty-one Fontan patients with cardiac magnetic resonance (CMR) data obtained greater than 1 year before liver biopsy data were included. Computational fluid dynamic simulations were performed to quantify total cavopulmonary connection (TCPC) flow dynamics using patient-specific anatomies and blood flow waveforms reconstructed from CMR data. Collagen deposition (a measure of liver fibrosis) was quantified by digital image analysis of Sirius red-stained slides. Statistical analyses were performed to investigate potential relationships between Fontan hemodynamics and liver fibrosis. RESULTS: With an average time of 6.7 ± 2.9 years (range, 2-11 years) between CMR and biopsy, TCPC resistance and left pulmonary artery stenosis showed significant, positive correlations with magnitude of liver fibrosis (r = 0.54, P = .026; and r = 0.55, P = .028, respectively). The change in inferior vena cava flow rate over time also showed a significant positive correlation with magnitude of liver fibrosis (r = 0.91, P = .001). CONCLUSIONS: TCPC resistance, left pulmonary artery stenosis, and increased inferior vena cava flow are positively associated with liver fibrosis after Fontan operation and hold promise as important predictors of hepatic decline. These findings encourage preprocedural planning and interventional strategies to improve TCPC performance and reduce vessel stenosis. Further investigation is warranted to design the ideal Fontan circulation and optimize flow dynamics to reduce the risk of liver fibrosis.

GBCAs and Risk for Nephrogenic Systemic Fibrosis: A Literature Review.

PURPOSE: To examine the risks of using of gadolinium-based contrast agents (GBCAs) in magnetic resonance (MR) imaging and explore strategies to reduce the likeliness of adverse effects in patients who might be at risk for developing nephrogenic system fibrosis (NSF). METHODS: A search of 3 scholarly databases was performed to identify articles that discuss adverse reactions to GBCAs, specifically relating to kidney function, in MR examinations. A total of 20 peer-reviewed articles were analyzed. DISCUSSION: Safety of contrast media is related to the stability of the chelate bond (ie, macrocyclic or linear). Patients who have decreased kidney function or chronic kidney disease are at higher risk for an adverse reaction to GBCAs; typically, macrocyclic contrast agents are considered safer than linear contrast agents for patients at risk for developing NSF because of their higher kinetic stability. Recommended doses of gadolinium should be adhered to carefully for all patients in conjunction with the glomerular filtration rate guidelines for contrast administration defined by the American College of Radiology. CONCLUSION: Although there are advantages to contrast use in MR examinations, technologists should work closely with referring physicians and radiologists to minimize risks for developing NSF in patients who have decreased kidney function.