Brain natriuretic peptide, a biomarker for cardiac function, is widely used in clinical practice and is closely related to the outcomes of patients with CAD.[11,12] It reflects the state of ventricular wall tension and volume load, and is associated with the renin-angiotensin and sympathetic nervous systems which contribute to the development of CIN.[7] Studies have reported that the brain natriuretic peptide can be viewed as a predictor of CIN. The gene discussed is REN; the disease is coronary artery disorder.