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Cardiac Surgery AKI CKD Risk — ESENeph MCQ

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ModerateAcute Kidney InjuryCardiac Surgery AKI CKD RiskESENeph

A 50-year-old man with CKD G3b from diabetic nephropathy has a coronary angiogram showing severe triple vessel disease. His cardiologist recommends CABG. His eGFR is 32 mL/min/1.73m2. What unique perioperative renal risk does cardiac surgery with cardiopulmonary bypass carry?

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Correct answer: C — AKI occurs in 20-40% of cardiac surgery patients with CKD due to hypoperfusion during bypass, inflammatory response, nephrotoxic contrast, and haemolysis; the risk increases significantly with pre-existing CKD

Cardiac surgery-associated AKI (CSA-AKI) is a major complication, occurring in 20-40% of CKD patients. Mechanisms include renal hypoperfusion during cardiopulmonary bypass (non-pulsatile flow, haemodilution), systemic inflammatory response from the bypass circuit, micro-embolisation, haemolysis, and nephrotoxic contrast from prior angiography. Pre-existing CKD is one of the strongest risk factors. Strategies to reduce risk include maintaining adequate perfusion pressure, avoiding nephrotoxins, and minimising bypass time. Off-pump surgery may reduce AKI risk but data is inconsistent.

Reference: KDIGO 2012 – AKI (Cardiac Surgery Section); NICE – Cardiac Surgery