Cardiorenal syndromes: definition and classification

Area of Science:

• Cardiology
• Nephrology
• Internal Medicine

Background:

• The cardiorenal syndrome (CRS) describes the complex interplay between heart and kidney dysfunction.
• Existing classifications needed refinement to encompass the bidirectional and interrelated nature of these organ interactions.

Purpose of the Study:

• To present a comprehensive classification of cardiorenal syndrome (CRS) into five distinct subtypes.
• To highlight the primary and secondary pathologies, time-frames, and systemic causes of simultaneous cardiac and renal codysfunction.

Main Methods:

• Review and synthesis of existing literature on cardiorenal interactions.
• Development of a five-subtype classification system based on etymology and pathophysiological mechanisms.

Main Results:

• Type 1 CRS: Acute cardiac dysfunction leading to acute kidney injury.
• Type 2 CRS: Chronic cardiac dysfunction causing chronic kidney disease.
• Type 3 CRS: Acute renal dysfunction inducing acute cardiac disorder.
• Type 4 CRS: Chronic kidney disease impairing cardiac function and increasing cardiovascular risk.
• Type 5 CRS: Systemic conditions causing simultaneous cardiac and renal dysfunction.

Conclusions:

• The five-subtype classification provides a framework for understanding diverse cardiorenal interactions.
• Identifying specific CRS subtypes and their mechanisms is crucial for clinical management and future research.