When should I consider referring a patient with cardiorenal syndrome to a specialist for further evaluation and management?

Consider referring a patient with cardiorenal syndrome to a specialist for further evaluation and management if any of the following are present:

• A 5-year risk of needing renal replacement therapy greater than 5%, as measured by the 4-variable Kidney Failure Risk Equation.
• An albumin-to-creatinine ratio (ACR) of 70 mg/mmol or more, unless it is known to be caused by diabetes and already appropriately treated.
• An ACR of more than 30 mg/mmol together with haematuria.
• A sustained decrease in estimated glomerular filtration rate (eGFR) of 25% or more and a change in eGFR category within 12 months.
• A sustained decrease in eGFR of 15 ml/min/1.73 m² or more per year.
• Hypertension that remains poorly controlled despite the use of at least four antihypertensive medicines at therapeutic doses.
• Known or suspected rare or genetic causes of chronic kidney disease (CKD).
• Suspected renal artery stenosis.
• Acute kidney injury (AKI) with complications such as hyperkalaemia, metabolic acidosis, symptoms or complications of uraemia (e.g., pericarditis or encephalopathy), fluid overload, or pulmonary oedema not responding to medical management.
• Stage 3 AKI or higher, or AKI with no clear cause or inadequate response to treatment.

Referral should be timely to allow specialist assessment and management, including consideration of renal replacement therapy if indicated. Shared decision making with the patient and multidisciplinary team involvement is essential.

These criteria align with NICE guidelines on chronic kidney disease and acute kidney injury management, which are relevant to patients with cardiorenal syndrome due to the interplay of cardiac and renal dysfunction.

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