Circulating miR-423-5p fails as a biomarker for systemic ventricular function in adults after atrial repair for transposition of the great arteries

Background: Recently, the microRNA miR-423-5p was identified as a biomarker for left ventricular heart failure. Its role in patients with a systemic right ventricle and reduced ejection fraction after atrial repair for transposition of the great arteries has not been evaluated. Methods: In 41 patients and 10 age- and sex-matched healthy controls circulating miR-423-5p concentration was measured and correlated to clinical parameters, cardiac functional parameters assessed by magnetic resonance imaging, and cardiopulmonary exercise testing. Results: Levels of circulating miR-423-5p showed no difference between patients and controls. Further, there was no correlation between miR-423-5p and parameters of cardiopulmonary exercise testing or imaging findings. Conclusions: In patients with a systemic right ventricle and reduced ejection fraction miR-423-5p levels are not elevated. Therefore, circulating miR-423-5p is not a useful biomarker for heart failure in this patient group.