Cardiorenal syndrome
Cardiorenal syndrome is the bidirectional dysfunction in which heart disease impairs the kidneys or kidney disease impairs the heart, classified into five types. In decompensated heart failure it is driven more by venous congestion than low output, so the core treatment is decongestion with adequate diuresis while preserving perfusion.
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What this article covers
- Overview
Definition: cardiorenal syndrome is a spectrum of disorders in which dysfunction of the heart and kidneys is bidirectional, so that acute or chronic disease in one organ causes dysfunction in the other, classified into five types.
- Epidemiology
Common in hospitalized heart failure, where worsening renal function frequently occurs.
- Risk factors
Established heart failure and chronic kidney disease.
- Pathophysiology
Venous congestion: elevated central venous pressure raises renal venous and interstitial pressure, reducing the trans-glomerular gradient and glomerular filtration, a dominant mechanism in decompensated heart failure.
- Clinical features
Congestion: elevated jugular venous pressure, edema, and dyspnea.
- Differential diagnosis
Prerenal azotemia from overdiuresis: a rising creatinine with a low jugular venous pressure, flat inferior vena cava, and a bland urine, discriminated from cardiorenal congestion by genuine hypovolemia rather than a raised venous pressure.
- Diagnosis
Establish clinically by concurrent cardiac and renal dysfunction, distinguishing congestion from true hypoperfusion: the diagnostic basis is recognizing worsening renal function in the context of…
- Management
First-line, decongest with adequate intravenous loop diuretics: give an intravenous loop diuretic (furosemide 40 to 80 mg IV, or higher in chronic users or renal impairment) titrated to a clear…
- Complications
Refractory volume overload and diuretic resistance.
- Prognosis
Worse outcomes than heart failure without renal involvement.
- Prevention
Optimize volume status and guideline-directed heart failure therapy.
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Related articles
- Heart failure
Heart failure is a clinical syndrome of impaired cardiac filling or ejection causing congestion and reduced perfusion, classified by ejection fraction. Diagnosis integrates symptoms, signs, natriuretic peptides, and echocardiography, and treatment of reduced-ejection-fraction disease is quadruple guideline-directed therapy, with device therapy and cause-specific management.
- Acute heart failure
Acute heart failure is the rapid onset or worsening of heart failure symptoms requiring urgent therapy, most often pulmonary congestion from a precipitant such as ischemia, arrhythmia, or nonadherence. Management is oxygen, intravenous diuretics, and vasodilators for the congested-but-perfused patient, with inotropes or support for the hypoperfused patient.
- Right heart failure
Right heart failure is inability of the right ventricle to maintain output at acceptable filling pressures, most often from left heart failure or pulmonary hypertension, and acutely from pulmonary embolism or right ventricular infarction. It causes systemic venous congestion, and management centers on the underlying cause, careful volume and afterload optimization, and preload-dependent support in acute disease.