Cardiac magnetic resonance imaging–derived cardiac index is associated with adverse outcomes in patients with single-ventricle Fontan circulation: a preliminary study

MethodsThirty -four patients undergoing the Fontan procedure were retrospectively enrolled in the study.Cardiopulmonary exercise testing was performed on Treadmill Ergometer ZAN Ergo 600s (Delmar Reynolds, Irvine, California, United States).Maximal oxygen uptake (VO 2 max) was measured by a modified Bruce protocol.Biochemical data were obtained using standard assay techniques.Collected parameters included serum concentrations of total protein, aspartate and alanine transaminases, total bilirubin, iron, creatinine, thyroid -stimulating hormone, and C -reactive protein.Blood cell tests provided data on hemoglobin levels, platelet and leukocyte counts, and mean corpuscular volume.Additionally, a glomerular filtration rate was estimated.Cardiac magnetic resonance imaging was performed using a 1.5 Tesla scanner (Avanto and Avantofit, Siemens Healthineers, Erlangen, Germany) to evaluate the CO.The CO was calculated according to the following formula: CI = CO / body surface area.Adverse events were identified and followed up for a mean of 4 years.Those events included arrhythmia, nonelective hospitalization, death, heart transplant, lower New York Heart Association (NYHA) functional class, and decreased VO 2 max.The study protocol was approved by an ethics committee.Patient consent was not required owing to the retrospective design of the study.