Update on Contrast-Induced Nephropathy: Recent Developments in Its Prevention, Early Diagnosis, and Therapy

Contrast-induced nephropathy (CIN), now more accurately referred to as contrast-induced acute kidney injury (CI-AKI), remains a major cause of hospital-acquired acute kidney injury (AKI) and is associated with increased morbidity and mortality, particularly in high-risk patients. This condition occurs following the intravascular administration of iodinated radiocontrast media (RCM), especially in individuals with pre-existing chronic kidney disease (CKD), diabetes mellitus, heart failure, advanced age, or exposure to high contrast volumes. The pathophysiology of CI-AKI is multifactorial and involves renal hemodynamic alterations, direct tubular toxicity, oxidative stress, inflammatory activation, and endothelial dysfunction, ultimately leading to tubular injury and reduced glomerular filtration rate (GFR). Traditional diagnostic markers such as serum creatinine (sCr) and estimated glomerular filtration rate (eGFR) are limited by low sensitivity and delayed response, prompting growing interest in novel biomarkers, including cystatin C (CysC), β-2 microglobulin (β-2M), Interleukin-18 (IL-18), Kidney Injury Molecule-1 (KIM-1), Neutrophil Gelatinase-Associated Lipocalin (NGAL), and osteopontin (OPN), which allow earlier detection and risk stratification. Preventive strategies remain the cornerstone of management and include optimizing hydration protocols, minimizing contrast dose, selecting low- or iso-osmolar agents, and individualized risk assessments. Despite extensive research into pharmacological and procedural interventions, no effective treatment for established CI-AKI exists, underscoring the critical importance of prevention and ongoing investigation into safer contrast agents and innovative prophylactic approaches.