Mid-Regional Pro-Adrenomedullin: An Indicator of the Failing Fontan Circuit in Patients with Univentricular Hearts?

AIMS: In patients after the Fontan procedure, assessment of a failing Fontan circuit is difficult. Natriuretic peptides failed to be reliable markers of functional status or systemic ventricular function in this patient cohort. The aim of the study was to assess the clinical utility of mid-regional pro-adrenomedullin (MR-proADM) in patients after the Fontan procedure. METHODS AND RESULTS: Plasma MR-proADM levels were measured in 53 patients after the Fontan procedure and compared with clinical status, echocardiographic, and laboratory parameters including NT-proBNP. Median MR-proADM levels were 0.668 nmol/L in patients with a failing Fontan circuit as compared with 0.357 nmol/L in those without Fontan failure (P = 0.001). Levels of MR-proADM were significantly related to the presence of Fontan failure (r = 0.444, P = 0.001), NYHA class (r = 0.434, P < 0.001), and γ-glutamyltransferase levels (r = 0.554, P < 0.001). According to receiver operating characteristic (ROC) curve analysis, Fontan failure was best predicted by MR-proADM [area under the curve (AUC) 0.985, P = 0.001], NT-proBNP (AUC 0.947, P = 0.003), NYHA class (AUC 0.962, P = 0.002), and the inspiratory/expiratory ratio of the inferior vena cava diameter (AUC 0.973, P = 0.007). The optimal cut-off of MR-proADM for the prediction of Fontan failure was 0.520 nmol/L with a sensitivity of 100%, specificity of 93.9%, positive predictive value of 57.1%, negative predictive value of 100%, and overall accuracy of 94.3%. However, the data should also be validated in a larger cohort of patients. CONCLUSION: Serial measurements of MR-proADM levels may help identify patients at risk for a failing Fontan circulation especially when exceeding 0.520 nmol/L. In these patients, intensified medical care should be considered to prevent further clinical deterioration.