Cardiac output drop reflects circulatory attrition after Fontan completion: serial cardiac magnetic resonance study

Cardiac magnetic resonance (CMR) imaging is a main diagnostic tool in follow-up of Fontan patients. However, the value of serial CMR’s for evaluation of Fontan attrition is unknown. Prospective study of serial CMR’s in patients after Fontan completion. Analysis of time-dependent evolution of blood flow distribution, ventricular volumes and function. Prospective single center study of 281 CMR’s (between 2012-2022) in 88 Fontan patients with distribution of blood flows, measurements of ventricular volumes and ejection fraction. Linear mix model regression for repeated measurements was used to analyze changes of measurements across serial CMR’s. During a time interval of 10 years, the median number of CMR’s per patient was 3 (range 1-5). Indexed flows of ascending aorta, caval veins, pulmonary arteries decreased significantly across serial CMR’s. Although a decrease of mean indexed aortic flow (3.03 ± 0.10 L/min/m2 at 1st CMR versus 2.36 ± 0.14 L/min/m2 at 4th CMR, p < 0.001) was observed, ejection fraction did not decline (50 ± 1% at 1st CMR versus 54 ± 2% at 4th CMR, p = 0.070). Indexed ventricular volume did not differ significantly across serial CMR’s. The decrease of indexed aortic and cavo-pulmonary flows reflects the attrition of univentricular circulation and can be detected by means of serial CMR’s. Ventricular systolic dysfunction does not contribute significantly to this attrition. In order to detect significant change of indexed aortic flow, we recommend performing serial CMR’s as routine practice in the Fontan population.