Acute Kidney Injury after Cardiac Surgery: Does the Time Interval from Contrast Administration to Surgery Matter?

OBJECTIVE:

The authors sought to evaluate the association between the time interval from contrast administration to cardiac surgery and postoperative acute kidney injury (AKI).

DESIGN:

A retrospective observational study over a 1-year period.

SETTING:

A US academic medical institution.

PARTICIPANTS:

Six hundred forty-four adult patients undergoing nonemergent cardiac surgery.

INTERVENTIONS:

No interventions were performed as part of the study.

MEASUREMENTS AND MAIN RESULTS:

AKI was defined as an increase in serum creatinine by ≥0.3 mg/dL or ≥50% above baseline within the first 2 postoperative days or the commencement of renal replacement therapy within the same period. Using a contrast-to-surgery time interval >7 days as the baseline, multivariable logistic regression analysis determined the association between a contrast-to-surgery time interval ≤1 day or 2 to 7 days and postoperative AKI adjusting for potential confounding variables. The incidence of AKI within the study cohort was 21.9%. After adjusting for other covariates, there was no association between the contrast-to-surgery time and AKI (odds ratio [OR] ≤1 day = 0.93; 95% confidence interval [CI], 0.52-1.66; p = 0.81; OR = 2-7 days = 1.28; 95% CI, 0.78-2.11; p = 0.34).

CONCLUSIONS:

In an appropriately selected population, cardiac surgery can be performed within 1 day of cardiovascular catheterization and contrast administration without an increase in the incidence of postoperative AKI. Recommendations to delay cardiac surgery for a specified period after contrast administration to reduce the risk of postoperative AKI are premature. Additional evidence is required before making recommendations on optimal surgical timing after contrast exposure.