Table 2.
Summary of various mechanisms of cardiorenal syndrome
| Mechanism | Mediator | End-organ Outcome | |
|---|---|---|---|
| Heart | Kidney | ||
| • Increased central venous and intra-abdominal pressures | • Increased salt/water retention • Activation of RAAS/SNS |
• Acute/chronic HF • Adverse remodeling of heart and lungs |
• Renal venous congestion • Reduced GFR |
| • Reduced cardiac output and cardiac index | • Peripheral vasodilation/reduced vascular resistance • Reduced perfusion pressure |
• Activation of RAAS/SNS detrimental to heart • Cardiac ischemia from reduced perfusion |
• Reduced renal perfusion • Renal ischemia |
| • Neurohormonal dysregulation ◦ RAAS activation ◦ SNS activation ◦ Adenosine/AVP |
• Impaired baroreceptor reflexes • Increased renin secretion • Increased Ang II secretion • Increased aldosterone secretion • Increased ET-1 expression • Oxidative stress |
• Myocyte hypertrophy, left ventricular dysfunction • Proinflammation, profibrotic effect • Hypertension |
• Arteriolar vasoconstriction • Reduced GFR • Enhanced reabsorption of sodium/water • Proinflammation, profibrotic effect |
| • Oxidative stress | • Increased reactive oxygen species formation • Ang II–enhanced NADPH-oxidase activity • Uremic toxin–mediated cytokine release |
• Left ventricular hypertrophy • Accelerated atherosclerosis • Endothelial dysfunction • Inflammation • Fibrosis |
• Endothelial dysfunction • Accelerated atherosclerosis • Inflammation • Interstitial fibrosis |
| • Inflammatory mediators | • TNF-α • TWEAK • Members of IL-1 family • IL-6 • CRP |
• Atherosclerosis • Inflammation • Left ventricular dysfunction • Cardiac hypertrophy • Myocardial cell death • Fibrosis |
• Inflammation • Fibrosis • Atherosclerosis • Glomerular damage by mesangial cell apoptosis |
| • Renal failure–disturbances | • PBUTs (indoxyl sulfate, p-cresyl sulfate) • Chronic inflammatory cytokines • Oxidative stress • FGF-23 • Calcium/phosphate-mediated inflammation • Anemia |
• Endothelial dysfunction • Atherosclerosis • Left ventricular dysfunction • Cardiac hypertrophy |
• Atherosclerosis • Inflammation • Increased interstitial and perivascular fibrosis |
Abbreviations: Ang II, angiotensin II; AVP, arginine vasopressin; CRP, C-reactive protein; ET-1, endothelin-1; FGF-23, fibroblast growth factor-23; GFR, glomerular filtration rate; IL, interleukin; PBUTs, protein-bound uremic toxins; RAAS, renin-angiotensin-aldosterone system; SNS, sympathetic nervous system; TNF-α, tumor necrosis factor alpha; TWEAK, tumor necrosis factor alpha–related weak inducer of apoptosis.