Contrast-induced acute kidney injury in patients undergoing PCI

The PCR Textbook

Summary

In spite of improvements in their chemical structure, ICA still possess kidney toxicity and represent one of the main causes of contrast-induced acute kidney injury (CI-AKI) and hospital-acquired renal failure. These iatrogenic complications are associated with increased in-hospital and long-term morbidity and mortality. Development of CI-AKI prevention strategies is ongoing, but an incomplete understanding of CI-AKI pathophysiology has hampered many efforts. The most popular theories include a combination of a direct toxic effect of ICA on renal tubular cells, free radical formation and decreased renal medullary blood flow resulting in medullary ischaemia. The definition of CI-AKI includes absolute (>0.5 mg/dl [>44 μM/l]) or relative (>25%) increase in serum creatinine (SCr) 48-72 hours after exposure to ICA compared to baseline SCr values, when alternative explanations for renal impairment have been excluded.

The risk of renal function impairment associated with percutaneous diagnostic and interventional procedures is low (0.6-2.3%) in the general population. However, it may be very high (up to 50%) in some subsets, especially in patients with major risk factors such as chronic kidney disease, advanced age and diabetes mellitus associated with pre-existing renal dysfunction. Because no effective treatment exists for CI-AKI, prevention remains the key strategy. Effective preventive approaches include the use of the smallest possible dose of low-osmolar or iso-osmolar ICA by means of specific strategies or dedicated devices, fluid administration (particularly using a strategy of high urine output with matched hydration), haemodynamic support, stopping nephrotoxic drugs and avoiding repeat ICA injections within 72 hours. Among possible prophylactic drug therapies, N-acetylcysteine, particularly when associated with adequate hydration in patients requiring large contrast volume, may have a dose-dependent protective effect. Similarly, high-dose statins may be effective in reducing CI-AKI risk. The purpose of this chapter is to review the available literature regarding CI-AKI in patients undergoing PCI and to provide a comprehensive and evidence-based analysis of risk factors, diagnosis and prevention strategies.

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