A New Clinical Entity Bridging the Cardiovascular System and the Kidney: The Chronic Cardiovascular-Kidney Disorder

The complex relationship between heart and kidney dysfunction has been a subject of medical inquiry since the 19th century. The term "cardio-renal syndrome" (CRS) was introduced in the early 2000s and has since become a focal point of research. CRS is typically categorized into five subtypes based on the sequence of cardiovascular and kidney disease events.

The cardiovascular-kidney-metabolic (CKM) syndrome, as defined by the American Heart Association, describes a set of interrelated metabolic risk factors and their effects on the kidneys and cardiovascular system. This syndrome emphasizes the complexity of managing patients with combined conditions and identifies several knowledge gaps, including disease mechanisms, clinical phenotype variability, and the impact of social determinants of health. The chronic cardiovascular-kidney disorder (CCKD) framework proposes a shift from the term "syndrome" to "disorder," focusing on concurrent cardiovascular and kidney problems regardless of their sequence.

(i) The CCKD concept calls for simplification and conceptual clarity, arguing that understanding the bidirectional acceleration of disease progression between heart and kidney dysfunction can lead to more effective treatment strategies. (ii) Both CKM and CCKD share common pathophysiological mechanisms and risk factors, including hypertension, diabetes, obesity, and dyslipidemia. Managing these conditions requires a comprehensive approach that addresses the underlying risk factors and pathophysiological mechanisms. (iii) Future directions include embracing precision medicine, public health strategies, interdisciplinary care models, and ongoing research and innovation. Both frameworks underscore the need for comprehensive, interdisciplinary care models and innovative treatment strategies to address the complex interplay between cardiovascular and kidney diseases.