ORIGINAL ARTICLE Vol. 44 (4): 726-733, July - August, 2018 doi: 10.1590/S1677-5538.IBJU.2017.0283 Acute kidney injury following radical cystectomy and urinary diversion: predictors and associated morbidity _______________________________________________ Yasser Osman 1, Ahmed M. Harraz 1, Samer El-Halwagy 1, Mahmoud Laymon 1, Ahmed Mosbah 1, Hassan Abol-Enein 1, Atalla A. Shaaban 1 1 Urology and Nephrology Center, Mansoura University, Egypt ABSTRACT ARTICLE INFO ______________________________________________________________ ______________________ Introduction: Acute kidney injury (AKI) after major surgeries is associated with signifi- Keywords: cant morbidity and mortality. We aim to report incidence, predictors and associated Acute Kidney Injury; Cystectomy; comorbidities of AKI after radical cystectomy in a large cohort of patients. Urinary Diversion Materials and Methods: We conducted a retrospective analysis of 1000 patients who underwent open radical cystectomy in a tertiary referral center. Perioperative serum Int Braz J Urol. 2018; 44: 726-33 creatinine measurements were used to define AKI according to the RIFLE criteria (as Risk, Injury and Failure). The predictors of AKI after surgery were determined using _____________________ univariate and multivariate analyses. Submitted for publication: Results: Out of 988 evaluable patients, AKI developed in 46 (4.7%). According to RIFLE June 12, 2017 criteria; AKI-Risk, AKI-Injury and AKI-Failure occurred in 26 (2.6%), 9 (0.9%) and 11 _____________________ (1.1%) patients, respectively. Multivariate analysis showed that performing nephro- Accepted after revision: ureterectomy with cystectomy (Odds ratio [OR]: 4.3; 95% Confidence interval [CI]: February 25, 2018 1.3-13.6; p=0.01) and the development of high grade complications (OR: 3.8; 95% CI _____________________ 1.9-7.2; p<0.0001) were independently associated with AKI. Published as Ahead of Print: Conclusions: AKI is a significant morbidity after radical cystectomy and the term March 18, 2018 should be included during routine cystectomy morbidity assessment. INTRODUCTION and mortality (3). It has been shown that pa- tients who partially recovered from an episode Radical cystectomy and urinary diver- of AKI are at higher risk of long-term mortality sion continue to be the basic modality for tre- (4) and those who completely recovered from an atment of localized muscle invasive bladder episode of AKI are more likely to develop inci- cancer in both genders (1). Following surgery, dent chronic kidney disease (CKD) (5) or even a wide scale of diversion-related complications end-stage renal disease (6, 7). The incidence and have been described and extensively analyzed predictors of AKI after major urologic surgeries including gastro-intestinal, urinary and renal are poorly studied in the literature and limited function complications (2). mainly to cardiothoracic and orthopedic surge- Acute kidney injury (AKI) is a devasta- ries (8-10). This study was conducted to inves- ting co-morbidity that is commonly encounte- tigate the incidence and predictors of AKI in a red in critically ill patients and after major sur- large cohort of patients undergoing radical cys- geries and is associated with severe morbidity tectomy and urinary diversion. 726 IBJU | ACUTE KIDNEY INJURY FOLLOWING RADICAL CYSTECTOMY MATERIALS AND METHODS lowest value of postoperative hemoglobin. Opera- tive data included performing nephroureterectomy Study Design with cystectomy or not and type of the urinary di- A retrospective cohort study was conduc- version. The operating time was not reported in all ted in 1000 patients underwent radical cystectomy patients; therefore, this item was eliminated from and urinary diversion at our tertiary referral cen- the analysis. ter between January 2004 and September 2009. Postoperative complications were classi- The study received our internal review board ap- fied and graded according to the proposed modifi- proval with informed consent waived because of cation of the Dindo-Clavien system (14) and grade the retrospective nature of the study. Patients with I and II were considered minor and grades III to IV missed data about serum creatinine (SCr) measu- were considered major. rements were excluded (n=12). All patients un- derwent open radical cystectomy with standard Outcome Assessment pelvic lymphadenectomy up to the level of the The primary outcome of the study is the common iliac artery and followed by urinary di- development of AKI. Three SCr measurements version. During the postoperative period, all ure- were used to define AKI. Baseline SCr is the nea- ters were stented for 11-to-13 days after ortho- rest value before or at time of surgery. During the topic bladder substitution and 9 days after ileal postoperative period, the peak SCr elevations and conduit urinary diversion. Patients were kept in SCr at discharge were recorded. Patients with per- the hospital until catheter free; 21 days and 11 sistent rise of SCr at time of discharge were inclu- days for orthoptic and ileal conduit diversions, ded. Patients with temporary transient rise were respectively. excluded from the study. Based on these readings, AKI was defined according to the RIFLE criteria Data Collection and Measurements by a persistent (till time of discharge) increase of Data were collected from a prospectively SCr measurements 1.5 times the baseline value maintained electronic database at our institution. (15). Acute kidney injury was further classified Demographics included age, gender, body mass in- into AKI-Risk (SCr increases >1.5 times the base dex (BMI) with obese patients defined as BMI >30, line value), AKI-Injury (SCr increased >2 times and the presence of diabetes mellitus or hyperten- the baseline value) and AKI-Failure (SCr increased sion. Patient’s co-morbidities were assessed using >3 times the baseline value). As the scope of this age-adjusted Charlson Co-morbidity index (CCI) study was limited to the perioperative period, AKI as previously described (11). The presence of CKD categories Loss of function and End-stage renal was diagnosed as proposed by the National Kid- disease were not evaluated. ney Foundation by having estimated glomerular filtration rate (eGFR) <60mL/min/1.7m2 (12). Ba- Statistical analysis seline GFR was estimated using the Chronic Kid- ney Disease Epidemiology Collaboration Equation Continuous variables were described as (CKD-EPI) (13). In patients presented with oliguria mean±SD for parametrically-distributed variables or anuria, measurements were obtained after de- and median (interquartile range [IQR]) for non- compressing the pelvicalyceal system by percuta- -parametric variables and nominal variables as neous nephrostomy tube and SCr measures had frequencies (percentages) in each category. Age stabilized. and BMI were described as continuous and nomi- Recorded laboratory values included he- nal variables. We determined the incidence of AKI moglobin (anemia was defined as <10gm/dL) and after radical cystectomy and urinary diversion. albumin (hypoalbuminemia was defined as serum Continuous variables were compared between the albumin <3.5gm/dL). The rate of blood loss was two groups by student t test and categorical va- described as hemoglobin deficit and was calcula- riables by Chi-square test. Patient’s demographics, ted by the difference between preoperative and the operative and postoperative data were tested for 727 IBJU | ACUTE KIDNEY INJURY FOLLOWING RADICAL CYSTECTOMY association with the occurrence of AKI. Signifi- Table 1 - Demographics for patients undergoing radical cant factors were entered into a binary logistic re- cystectomy and urinary diversion. gression model to determine the independent fac- tors associated with AKI. Further sub-analysis of No. (988) the cohort was performed excluding patients un- Age, yr, mean, (SD) 58 (8.2) derwent nephroureterectomy with cystectomy, to Gender, no. (%) account for a more homogenous study population. Male 811 (82.1) RESULTS Female 177 (17.9) Urinary diversion, no. (%) Patient’s Characteristics Orthotopic 574 (58.1) A total of 988 patients (82.1% males) were Ileal conduit 387 (39.2) eligible for the perioperative assessment of AKI. Continent cutaneous/rectal 27 (2.7) Of our study population, 72.9% were considered to have normal preoperative renal function (eGFR Histopathology, no. (%) ≥60mL/min./m2). Ileal orthotopic bladder subs- TCC 690 (69.8) titution was the most popular type of diversion SCC 193 (19.5) and urothelial carcinoma was the most common Adenocarcinoma 61 (6.2) histopathological type. Patient’s demographics are Others 44 (4.5) displayed in Table-1. Tumor stage, no. (%) T or less 139 (14.1) Incidence and independent variables associated 1 with AKI after radical cystectomy T2 558 (56.5) Acute kidney injury developed in 46 (4.7%) T3 171 (17.3) patients after radical cystectomy. According to RI- T 77 (7.8) FLE criteria; AKI-Risk, AKI-Injury and AKI-Failu- 4 T 43 (4.4) re occurred in 26 (2.6%), 9 (0.9%) and 11 (1.1%) x patients, respectively. N stage Table-2 presents the association between No 676 (68.4) the development of AKI and various study po- N 106 (10.7) pulation characteristics. Comparing patients with 1 N 130 (13.2) and without AKI, there was no significant diffe- 2 N 76 (7.7) rence regarding age, gender, presence of DM, CKD x or hypertension, BMI or preoperative SCr measu- SD = Standard deviation; CKD = Chronic kidney disease; TCC = Transitional cell rements. Similarly, type of urinary diversion did carcinoma; SCC = Squamous cell carcinoma