Early Invasive Treatment for ACS Increases Risk of AKI

For patients with acute coronary syndrome (ACS), early catheterization may increase the risk of acute kidney injury (AKI) but is also associated with better long-term survival, concludes a study in the British Medical Journal.

Health data from Alberta were used to identify about 10,500 patients treated for non-ST elevation ACS between 2004 and 2009. Patients with AKI and control individuals free of AKI were stratified by baseline estimated GFR and then matched according to a propensity score for early invasive treatment—i.e., coronary catheterization within 2 days. Early invasive treatment was analyzed as a risk factor for AKI, kidney injury requiring dialysis, progression to ESRD, and death of any cause.

Overall, about 41 percent of patients underwent early invasive treatment. Compared with similar patients treated conservatively, the group receiving early invasive treatment had a modest but significant increase in AKI risk: 10.3 versus 8.7 percent, risk ratio 1.18. The rate of AKI patients requiring dialysis was low in both groups: 0.4 and 0.3 percent, respectively. At a median 2.5 years of follow-up, the rate of progression to ESRD was also similar between groups: 0.3 and 0.4 events per 100 person-years.

However, all-cause mortality was significantly lower in the group receiving early invasive treatment: 2.4 versus 3.4 events per 100 person-years, risk ratio 0.69. Analyses of patients with reduced kidney function at baseline and with the use of different definitions of early invasive treatment showed similar patterns.

When indicated, early invasive treatment for ACS improves long-term survival. The new study is one of the first to compare AKI risks and consequences in ACS patients undergoing early invasive versus conservative treatment.

The results show a small but significant increase in AKI risk with early invasive treatment. However, there was no difference in the rates of AKI requiring dialysis or progression to ESRD, whereas early invasive treatment was associated with improved survival. “[T]hese results suggest that invasive treatments should not be withheld solely because of concern they might increase the risk of kidney injury,” the researchers write [James MT, et al. Renal outcomes associated with invasive versus conservative management of acute coronary syndrome: propensity matched cohort study. BMJ 2013; 347:f4151].