Acute kidney injury defined according to the 'Risk,' 'Injury,' 'Failure,' 'Loss,' and 'End-stage' (RIFLE) criteria after repair for a ruptured abdominal aortic aneurysm

Acute kidney injury (AKI) is a serious complication after repair of a ruptured abdominal aortic aneurysm (RAAA). In the present Society for Vascular Surgery (SVS)/International Society for CardioVascular Surgery (ISCVS) reporting standards patients are classified as no dialysis (grade I), as temporary dialysis (grade II), and as permanent dialysis or fatal outcome (grade III). However, AKI is a broad clinical syndrome including more than the requirement for renal replacement therapy. The recently introduced 'Risk,' 'Injury,' 'Failure,' 'Loss,' and 'End-stage' (RIFLE) classification for AKI comprises three severity categories based on serum creatinine and urine output ('Risk,' 'Injury,' and 'Failure'). The objective of the present study was to assess the incidence of AKI using the RIFLE criteria (AKIRIFLE). Secondary objectives were to assess the incidence of AKI as defined using the SVS/ISCVS reporting standards (AKISVS/ISCVS) and the association between AKIRIFLE and death. This was an observational cohort study in 362 consecutive patients with an RAAA in three hospitals in Amsterdam (The Netherlands) between 2004 and 2011. The end points were the incidence of AKIRIFLE, of AKISVS/ISCVS, and the combined 30-day or in-hospital death rate. A multivariable logistic regression model was made to assess the association between AKIRIFLE and death after adjustment for preoperative shock profile (Glasgow Aneurysm Score) and postoperative shock profile (Acute Physiology and Chronic Health Evaluation [APACHE] II score, use of vasopressors, and fluid balance during the first 24 hours after intervention). AKIRIFLE occurred in 74% (267/362; 95% confidence interval [CI], 69%-78%), with 27% of these patients categorized as 'Risk' (71/267; 95% CI, 22%-32%), 39% categorized as 'Injury' (104/267, 95% CI, 33%-45%), and 34% categorized as 'Failure' (92/267; 95% CI, 29%-40%). AKISVS/ISCVS occurred in 48% (175/362; 95% CI, 43%-53%), with 53% of these categorized as 'grade I' (92/175; 95% CI, 45%-60%), 19% as 'grade II' (34/175; 95% CI, 14%-26%), and 28% as 'grade III' (49/175; 95% CI, 22%-35%). After multivariable adjustment for shock profiles the risk of dying in patients categorized as AKIRIFLE 'Failure' was greater than in patients without AKIRIFLE (adjusted odds ratio, 6.360; 95% CI, 2.231-18.130). The incidence of AKI defined according to the RIFLE criteria (74%) was greater than defined using the SVS/ISCVS reporting standards (48%) and patients categorized as 'Failure' using the RIFLE criteria had a greater risk of dying than patients without AKI. These results indicate that the problem of AKI is much bigger than previously anticipated and that minimizing injury to the kidney could be an important focus of future research on reducing the death rate after RAAA repair