Background: Some prior studies have suggested that the time to cardiac surgery after cardiac catheterization is inversely related to postoperative acute kidney injury (AKI). However, these studies, because of the small number of patients, were unable to adequately account for patient case-mix and included both those undergoing elective surgery and those undergoing urgent surgery.
Methods and results: We examined data on 2441 consecutive patients undergoing elective coronary artery bypass surgery (CABG) after cardiac catheterization. The association of post-CABG AKI (defined as increase in post-CABG serum creatinine ≥ 50% above baseline or the need for new dialysis) and time between cardiac catheterization and CABG was evaluated using multivariable logistic regression modeling. AKI occurred in 17.1% of CABG patients. The risk of AKI was highest in patients in whom CABG was performed ≤ 1 day after cardiac catheterization (adjusted mean rates [95% CI]: 24.0% [18.0%, 30.9%], 18.4% [14.8%, 22.5%], 17.3% [13.3%, 21.9%], 16.4% [12.6%, 20.8%], and 15.8% [13.7%, 18.0%] for days ≤ 1, 2, 3, 4, and ≥ 5, respectively; P=0.019 for test of trend). Post-CABG AKI was associated with increased risk of long-term death (hazard ratio 1.268, 95% CI 1.093, 1.471).
Conclusions: The risk of post-CABG AKI was inversely and modestly related to the time between cardiac catheterization and CABG, with the highest incidence in those operated ≤ 1 day after cardiac catheterization despite their lower risk profile. Whether delaying elective CABG >24 hours of exposure to contrast agents (when feasible) has the potential for decreasing post-CABG AKI remains to be evaluated in future studies.