Much ado about nothing: the impact of coronary angiography on kidney function in individuals with chronic kidney disease

Abstract Background and Objectives Chronic kidney disease (CKD) is associated with premature coronary artery disease and an increased risk of cardiovascular morbidity and mortality (1). Historically, there has been a tendency to delay or even avoid coronary angiography (CA) in those with CKD due to an increased risk of contrast-induced nephropathy or concern over precipitating the need for chronic dialysis. Such "renal nihilism" may account for the poorer outcomes observed in CKD patients who present with acute coronary syndromes (2). The role of this retrospective analysis was to evaluate the impact of CA on the temporal trend in kidney function in individuals with CKD over a 24-month period. Methods The clinical details of 120 individuals under long-term local follow-up by various Nephrology clinics (CKD clinic, low creatine clearance, polycystic kidney disease, transplant and immunosuppression clinics) was collected. All underwent CA locally. Kidney function was observed at set intervals of 12-, 9-, 6- and 3-months prior to CA, immediately post-CA, and at 3-, 6-, 9- and 12-months post-CA. Only results obtained after the desired time point but within 28 days were included. All CAs regardless of either their indication (elective or urgent) or whether percutaneous intervention (PCI) was performed, were included. Patients already on dialysis at the time of the CA were excluded. Statistical analysis was performed via one-way ANOVA. Results Patient characteristics are summarised in table 1. The average age of patients was 67, with a male preponderance (72%). 22% had CKD 3, 24% had CKD 4 and 12% had CKD 5. 9% were kidney transplant recipients. 37% underwent urgent CA whilst a total of 22% had PCI. 27% progressed to requiring renal replacement therapy (RRT). The mean length to RRT was 2.8 years. The rate of decline in kidney function in the last 12 months prior to CA was 7.7% and 6.3% in the year after CA (figure 1). There was no statistically significant difference in kidney function after CA (p = 0.395). This was replicated in analyses focussing on CKD classes 3, 4 and 5 individually, within stable kidney transplant recipients, and within analysis comparing PCI vs non-intervention CAs. Conclusion The results demonstrate CA does not accelerate the decline in kidney function in those with known CKD over a 12-month period, and suggests where appropriate, an invasive treatment strategy should be consider and utilised more often in this population.Table 1:Patient characteristicsFigure 1:Trend in eGFR relative to CA