Does safe dosing of iodinated contrast prevent contrast-induced acute kidney injury?
BACKGROUND
Previous work on contrast-induced acute kidney injury (CI-AKI) has identified contrast volume as a risk factor and suggested that there is a maximum allowable contrast dose (MACD) above which the risk of CI-AKI is markedly increased. We hypothesized that there is a relationship between contrast volume and CI-AKI and that there might be reason to track incremental contrast volumes above and below the MACD limit.


RESULTS
Consecutive patients undergoing percutaneous coronary intervention (PCI) were prospectively enrolled from 2000 to 2008 (n=10 065). Patients on dialysis before PCI were excluded (n=155). MACD was defined as (5 mL x body weight [kg])/baseline serum creatinine [mg/dL]) and divided into categories in which 1.0 reflects the MACD limit: < or =MACD ratios (<0.5, 0.5 to 0.75, and 0.75 to 1.0) and >MACD (1.0 to 1.5, 1.5 to 2.0, and >2.0). CI-AKI was defined as a > or =0.3 (mg/dL) or > or =50% increase in serum creatinine from baseline or new dialysis. Multivariable regression was conducted to evaluate the effect of exceeding the MACD on CI-AKI. Twenty percent of patients exceeded the MACD. Risk-adjusted CI-AKI increased by an average of 45% for each category exceeding the MACD (odds ratio, 1.45; 95% confidence interval, 1.29 to 1.62) Adjusted odds ratios for each category exceeding the MACD were 1.60 (95% confidence interval, 1.29 to 1.97), 2.02 (95% confidence interval, 1.45 to 2.81), and 2.94 (95% confidence interval, 1.93 to 4.48). CI-AKI for contrast dose <MACD showed no statistical difference (P=0.5).


CONCLUSIONS
Contrast volume is a key risk factor for CI-AKI and matters the most in the highest-risk patient. The incremental use of contrast beyond the MACD is associated with an increased risk of CI-AKI.
Brown
Jeremiah R
JR
Dartmouth Institute for Health Policy and Clinical Practice, Dartmouth College, Lebanon, NH, USA. jbrown@dartmouth.edu
Robb
John F
JF
Block
Clay A
CA
Schoolwerth
Anton C
AC
Kaplan
Aaron V
AV
O'Connor
Gerald T
GT
Solomon
Richard J
RJ
Malenka
David J
DJ
D058186:Acute Kidney Injury / Q000097:blood / Q000139:chemically induced / Q000517:prevention & control; D000368:Aged; D000369:Aged, 80 and over; D017130:Angioplasty / Q000009:adverse effects*; D003287:Contrast Media / Q000008:administration & dosage / Q000009:adverse effects*; D003327:Coronary Disease / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D003404:Creatinine / Q000097:blood; D004305:Dose-Response Relationship, Drug; D054796:Drug Dosage Calculations; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000209:etiology* / Q000517:prevention & control; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications
D003287:Contrast Media; D003404:Creatinine