Time from cardiac catheterization to cardiac surgery: a risk factor for acute kidney injury?

OBJECTIVES

Acute kidney injury can occur after cardiac catheterization and cardiac surgery. The negative effects of the contrast media and cardiopulmonary bypass on renal function may be additive when performed in close succession. The results in the literature are, however, conflicting.

METHODS

Preoperative, operative, perioperative and postoperative variables of 573 consecutive adult patients who underwent cardiac surgery on cardiopulmonary bypass were collected prospectively. Acute kidney injury (AKI) was defined according to the Acute Kidney Injury Network criteria based on changes in serum creatinine level within 48 h of surgery.

RESULTS

Acute kidney injury was detected in 233 patients (41%). In a multivariate analysis, older age (P = 0.01), longer cardiopulmonary bypass time (P = 0.003), lower preoperative haematocrit level (P = 0.02) and higher body mass index (P = 0.001) were found to be independently associated with development of acute kidney injury. Analysis of the time from cardiac catheterization to surgery by logistic regression modelling did not show any significant change in the risk of acute kidney injury. Risk related to time from catheterization to surgery was not increased even in the patients with elevated preprocedural creatinine levels (>106 μmol l(-1); P = 0.23), left ventricular dysfunction (ejection fraction <40%; P = 0.19) and older age (≥70 years; P = 0.86).

CONCLUSIONS

The time from cardiac catheterization to cardiac surgery is not a risk factor for the development of postoperative acute kidney injury even in patients with other risk factors. Surgical intervention should not be delayed in emergency or urgent cases. The optimization of renal function seems to be the correct strategy in clinically stable patients with risk factors for acute kidney injury.