Volume overload and cardiorenal syndromes

Area of Science:

• Cardiology
• Nephrology
• Pathophysiology

Background:

• Cardiorenal syndromes (CRSs) represent bidirectional pathophysiologic interactions between the heart and kidneys.
• Dysfunction in one organ can precipitate dysfunction in the other, necessitating a clear classification system.

Purpose of the Study:

• To outline the current classification of cardiorenal syndromes, encompassing 5 distinct subtypes.
• To emphasize the importance of understanding the primary and secondary pathologies, time frames, and organ dysfunction in CRS.

Main Methods:

• Classification based on the primary organ affected, the nature of dysfunction (acute/chronic), and the resulting impact on the other organ.
• Identification of 5 subtypes: Type 1 (heart to kidney, acute), Type 2 (heart to kidney, chronic), Type 3 (kidney to heart, acute), Type 4 (kidney to heart, chronic), and Type 5 (systemic insult).

Main Results:

• Type 1 CRS: Acute cardiac dysfunction leading to acute kidney injury.
• Type 2 CRS: Chronic cardiac dysfunction causing progressive chronic kidney disease.
• Type 3 CRS: Acute renal dysfunction leading to acute cardiac disorder.
• Type 4 CRS: Chronic kidney disease contributing to cardiac dysfunction and adverse cardiovascular events.
• Type 5 CRS: Systemic conditions (e.g., sepsis) causing simultaneous cardiac and renal dysfunction.

Conclusions:

• Biomarkers aid in characterizing CRS subtypes and guiding treatment timing and effectiveness.
• Understanding CRS subtypes and underlying mechanisms, including fluid status, is vital for clinical management and future research stratification.