Acute Kidney Injury and Renal and Cardiovascular Outcomes after Coronary Angiography in Alberta, Canada

Acute kidney injury (AKI) following radiocontrast exposure is common in hospitalized adults. AKI may lead to poor outcomes following coronary angiography, and fear of precipitating this complication may be one reason why not all eligible patients receive such invasive procedures. This thesis was undertaken with the overall objective of improving knowledge of the long-term outcomes associated with AKI after coronary angiography. We conducted a systematic review to summarize associations between AKI and adverse outcomes following coronary angiography. Twenty seven of 28 studies reported an increased risk of death in those with AKI and this association persisted in studies that adjusted for confounders and when methods to account for publication bias were applied. AKI was also consistently associated with cardiovascular events; however, studies examining the risks of chronic kidney disease, and end-stage renal disease were limited. To address knowledge gaps, we performed a cohort study examining long-term kidney function and clinical outcomes after coronary angiography in Alberta. Compared to patients without AKI, the adjusted odds of a decline in kidney function 3 months after angiography increased more than 4-fold with mild AKI, and more than 17-fold with moderate or severe AKI. Furthermore, among those with renal impairment after angiography, the adjusted decline in kidney function during subsequent follow-up was greater in those with AKI. AKI was also independently associated with increased long-term risks of death, end-stage renal disease, hospitalization for heart failure, and hospitalization with renal failure. We also compared the risks of AKI in a cohort of patients matched on propensity to receive early invasive versus conservative management for acute coronary syndrome. Early invasive management was associated with a modest increase in risk of AKI (8.8% versus 5.6%, risk ratio 1.52, 95% CI 1.29 to 1.80); however, the risks of dialysis and end-stage renal disease did not differ between matched groups. These findings suggest that patients who develop AKI after coronary angiography should be targeted for interventions to improve long-term outcomes; however, the risk of AKI should not delay or preclude invasive procedures.