Acute kidney injury in aortic surgery: retrospective analysis of risk factors and prospective study for its prevention

Small alterations of the renal function during hospital stay and more specifically in the postoperative period determine significant increase in hospital mortality. In order to determine the incidence of AKI (acute kidney injury) and the risk factors for its development in the postoperative period of elective surgical open repair of thoracoabdominal and abdominal aortic aneurisms, it was carried out a retrospective study through the year of 2000. It was found high incidence of AKI, defined as a 25% increase in baseline serum creatinine (SCr), which occurred in 57% of the patients, and in a more strict definition, 50% increase in SCr, which occurred in 33%. The independent risk factors for AKI 25% was the presence of supra-renal clamping (OR 6,9, IC 95% 1,32-36,12) and the total anesthesia duration greater than 339 min (OR 1,00 for each min above 339 min, IC 95% 1,003-1,016). For more serious AKI (50%), the hemodynamic instability, represented for the need of vasoactive drugs in the postoperative period, also was an independent risk factor (OR 7,4, IC 95% 1,84-30,16). The mortality rate found in the study was 42,8% in patients who had supra-renal aortic clamping, and 21,4% in those with only infra-renal aortic clamping. In this study, the independent risk factors for death was baseline glomerular filtration rate (GFR) less than 49mL/min (OR 17,07, IC 95% 2,00-145,23), the need of supra-renal aortic clamping (OR 9,6, IC 95% 1,37-67,88), AKI defined as an increase of 50% in baseline SCr (OR 8,8, IC 95% 1.31-59,39) and the hyperglycemia in the postoperative period (OR 19,99, IC 2,32-172,28). Thereafter, we tested the protective effect of NAC through a randomized, placebo-controlled, double-blind study with patients eligible for elective open surgical repair of thoracoabdominal e abdominal aortic aneurisms. NAC was give po 1200mg twice daily 24 hours before the operation, and for 48 hours after surgery 600mg twice daily iv. Forty-two patients were enrolled...