695 ACCURACY AND IMPLICATION OF PERCUTANEOUS RENAL BIOPSY IN THE MANAGEMENT OF RENAL MASSES

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tively studied. They were categorized by preoperative computed tomography(CT) using the Bosniak renal cyst classification system. All patient demographics, other image findings, and pathologic findings were compared within each category. RESULTS: A total of 96 patients with 97 cystic renal masses were included in this study. The pathologic review revealed RCC in 43(44%) and benign cysts in 54(56%) overall. There were no RCC in Bosniak category I and II cyst. For category IIF, III and IV, 3(17%) of 18, 21(54%) of 39 and 29(90%) of 32 were RCCs. Male gender, enhancement characteristics, thickness and irregularities of cyst wall and internal septation were significantly correlated with RCC. Patients older than 50 years had relative higher chances of RCC. For cyst size, 12(80%) of 15 cysts less than 2 cm were benign while only 31(38%) of 82 cysts greater than 2 cm were benign. For category IIF cysts, factors of age, cyst size, presence of calcification could predict the 3 RCCs of 18 cases. All of the RCC were younger than 50 years; all lesion were greater than 2 cm and lacked calcification. CONCLUSIONS: The Bosniak classification is useful for differential diagnosis and treatment plan of complex renal cysts. Our findings suggest the relative importance of patient age and mass size, especially for the management of Bosniak category IIF cysts. While enhancement characteristics, wall and septal thickness and irregularities again proved radiological significances, calcification of complicated renal cyst seems that it may be negatively related with the chance of cystic RCC. Source of Funding: None

693 ADULT COMORBIDITY EVALUATION-27 SCORE IS AN INDEPENDENT PREDICTOR OF POSTOPERATIVE RENAL DYSFUNCTION AND OVERALL SURVIVAL Conrad Maciejewski*, Sarah Moore, Brendan Diederichs, Paul Cartledge, Gerald Todd, Ronald Moore, Edmonton, Canada INTRODUCTION AND OBJECTIVES: The Adult Comorbidity Evaluation 27 (ACE-27) is a validated comorbidity analysis questionnaire. The aim of our study was to evaluate the role of ACE-27 comorbidity score in predicting postoperative renal function outcomes as well as overall survival. METHODS: The Alberta Urology Institute Nephrectomy Database is a comprehensive multicenter retrospective database encompassing all demographic, clinical, and pathologic outcomes of patients undergoing radical and partial nephrectomy for renal cell carcinoma in the last 5 years. A total of 690 patient charts have been abstracted. Preoperative demographic data was used to calculate ACE-27 comorbidity score. The Modification of Diet in Renal Disease equation was used to calculate GFR using preoperative and postoperative data within 3 months of surgery. Univariate and multivariate linear and logistic regression models were designed using age, tumor stage, GFR, surgical approach, ACE-27 score, and overall survival as covariates. RESULTS: A total of 690 patients were evaluated, with a mean age of 59. Stage distribution showed 46% T1a, 17% T1b, 19% T2, 15% T3, and 2% T4. Mean preoperative GFR was 85 ⫾ 30 ml/min. ACE-27 score distribution showed 34% scoring 0, 42% scoring 1, 16% scoring 2, and 7% scoring 3. Median follow up was 3.2 years. Univariate linear regression identified age, ACE-27 score, and surgical approach as predictors of postoperative GFR ⬍ 60 ml/min (p⬍0.0001). Multivariate linear regression analysis confirmed these results, with age, ACE-27 score, and surgical approach being independent predictors of postoperative GFR ⬍ 60 ml/min (p⬍0.0001). Survival data was available for 219 patients, with an overall 19.6% 5 year mortality. In multivariate logistic regression, age was the only statistically significant factor predicting mortality (p⫽0.009) with a trend for ACE-27 (p⫽0.08). Subgroup analysis of individual ACE-27 scores identified high comorbidity (ACE-27 ⫽ 3) to be an independent predictor of mortality (p⫽0.005).

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CONCLUSIONS: Our data support the use of ACE-27 comorbidity score as a prognostic tool in clinical decision making for surgical management of renal cell carcinoma, in regards to postoperative renal function outcomes and overall survival. Source of Funding: None

694 MEASUREMENT OF ISOPROSTANE FOR RENAL ISCHEMIA IN AN ANIMAL MODEL Zijun Wang, MD*, Kayleen Bailey, Leah Grossman, Dewan Majid, MBBS, PhD, Benjamin R. Lee, MD, New Orleans, LA INTRODUCTION AND OBJECTIVES: Surgery for renal cell carcinoma involves clamping the renal artery temporarily, making the kidney particularly susceptible to ischemic damage from both warm ischemia and reperfusion injury. Isoprostane represents one potential marker of oxidative injury, as this marker is formed by the free radicalcatalyzed peroxidation of arachadonic acid. The objective was to determine whether levels of renal interstitial Isoprostane can quantitate renal damage secondary to warm ischemia and reperfusion periods. METHODS: After approval by the IACUC, Sprague-Dawley rats were anesthesized and given intravenous administration of 6% albumin solution at rate of 20ul/min into the jugular vein and continual monitoring of the carotid artery blood pressure. A vascular Microdialysis Probe was inserted into the renal parenchyma to allow continuous dialysis and collection of the effluent for isoprostene levels. Following clamping of the renal vessels for predefined intervals of ischemia, the effluent from the BASi IV-10 Vascular Microdialysis Probe (10mm Membrane), which was collected during the following time periods: Preclamp (30min), clamp (15, 30, 45 and 60 min), postclamp (30min). The interstitial fluid samples were subsequently analyzed for isoprostane levels using a Cayman Chemical 8-isoprostane ELA Kit and BMG LABTECH OPTIMA microplate reader. RESULTS: In the 15 minute clamp period, the average increase in isoprostane from baseline level to clamp was 6.02 pg/mL/g of kidney and from baseline to post-clamp was 9.82 pg/mL/g. The 30 minute clamp period demonstrated a decrease in isoprostane from baseline to clamp of -0.26 pg/mL/g and an increase from baseline to post-clamp of 5.35 pg/mL/g. When the renal artery was clamped for 45 minutes, the increase in isoprostane from baseline to clamp was 8.78 pg/mL/g and from baseline to postclamp was 8.62 pg/ml/g. Finally, the increase in isoprostane after a 60 minute clamp increased from baseline to clamp level of 8.45 pg/mL/g and from baseline to postclamp level the greatest at 14.59 pg/mL/g. CONCLUSIONS: Clamping of the renal artery and vein produced increases in isoprostane levels during the ischemic period and larger increases during reperfusion. There was a trend for increased post-clamp isoprostane levels as clamp times increased from 30, 45, to 60 minutes. Our data has demonstrated that isoprostane levels are a potential real-time marker of renal ischemia and reperfusion injury. Source of Funding: Departmental

695 ACCURACY AND IMPLICATION OF PERCUTANEOUS RENAL BIOPSY IN THE MANAGEMENT OF RENAL MASSES Diana Londono*, Melanie Wuerstle, Tarek Danial, Gary Chien, Los Angeles, CA INTRODUCTION AND OBJECTIVES: Percutaneous renal needle biopsy is gaining relevance and reemerging in clinical decisionmaking as the approach to management of renal masses is evolving. Particularly for small renal masses (SRMs) 4 cm or less, the clinical yield, determination of tumor histology, and prediction of final histologic subtype in biopsies for renal cell carcinoma may affect patient treatment options. We aim to characterize renal biopsy results in the recent

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decade, assess the accuracy of renal biopsy for predicting tumor histologic subtype and nuclear grade, and illustrate the role of renal biopsy in surgical versus non-surgical management. METHODS: A retrospective chart review was performed including patients in the Southern California Kaiser Permanente Medical Region that underwent either CT or ultrasound guided core percutaneous renal biopsy of a solid renal mass from January 2005 to December 2009. Patients were stratified by size of renal mass, comparing SRMs (less than or equal to 4 cm) to larger renal tumors. Initial biopsy results including tumor histology and nuclear grade were evaluated and related to postoperative pathology specimens when surgery was performed. RESULTS: The study included 126 patients (129 renal units with 132 biopsies). Sixty-three patients (50%) ultimately underwent surgery (23 partial and 40 radical nephrectomies). Patients who did not have surgical intervention tended to be older, average 68 years old versus 61 years old and have larger tumors 5.5 cm versus 4.0 cm. The overall sensitivity for detecting cancer (verified by final pathology) in our series was 75.4% with 100% specificity. The positive predictive value for patients who underwent surgery was 100% and negative predictive value 11.7%. When evaluating factors associated with accuracy of predicting cancer, larger tumor size has an odds ratio of 1.21 (p⫽ 0.10) and increasing number of biopsy samples has an odds ratio of 1.57 (p ⫽ 0.17). CONCLUSIONS: Percutaneous renal needle biopsy in the modern era has respectable sensitivity, excellent specificity and good concordance with final pathology. This modality can assist in clinical decision-making for renal masses, particularly for SRMs, as treatment options are expanding. Description of biopsies MASS ⬍/ ⫽ 4 cm Number of biopsies (%) RENAL BIOPSIES (n⫽132)

MASS ⬎ 4 cm Number of biopsies (%)

59 (44.7%)

73 (55.3%)

6 (10.2%)

1 (1.4%)

Benign biopsy

21 (35.6%)

17 (23.3%)

Cancer in biospy

32 (54.2%)

55 (75.3%)

Non diagnostic biopsy

NON DIAGNOSTIC OR BENIGN BIOPSY Mass excised with surgery Cancer in nephrectomy specimen

Cancer in nephrectomy specimen Concordance to renal cancer subtype Concordance to Fuhrman Grade

Source of Funding: None

697 A CLASSIFICATION TREE FOR THE PREDICTION OF BENIGN DISEASE IN THE MANAGEMENT OF RENAL MASSES: AIDING THE CLINICIAN’S THOUGHT PROCESS Ricardo A. Rendon*, Ross J. Mason, Susan Kirkland, Joseph G. Lawen, Mohamed Abdolell, Halifax, Canada

9/27 (33.3%)

8/18 (44.4%)

8 (88.9%)

7 (87.5%)

15/32 (46.9%)

31/55 (56.4%)

15 (100.0%)

31 (100.0%)

11/11 (100.0%)

16/18 (88.9%)

2/4 (50.0%)

5/9 (55.6%)

CANCER IN BIOPSY Mass excised with surgery

METHODS: 90 patients with solitary kidneys undergoing elective partial nephrectomy were randomized to fenoldopam or placebo in a double-blind protocol. Patients assigned to fenoldopam received an infusion rate of 0.1 ␮g/kg/min started after general anesthesia induction and continued for 24 hours. Placebo patients were given comparable volumes of saline. The primary outcome was the increase in GFR from preoperative value to the third postoperative day, as determined by a Wilcoxon rank-sum test. Repeated-measures analysis of variance was used to assess overall and time-specific effects of fenoldopam on log-transformed SCr, after adjusting for baseline values. RESULTS: Among 90 enrolled patients, 13 met intra-operative exclusion criterion; leaving 77 patients to be analyzed (fenoldopam: n⫽43). Baseline and intraoperative covariables were well-balanced in the randomized groups. The mean ⫾ SD of ischemia time was 22⫾8 and 23⫾7 minutes for fenoldopam vs. placebo patients; the fraction of renal resection was 23⫾14 and 25⫾12% for the two groups. There was no significant effect of fenoldopam (vs. placebo) on the percent change in GFR from baseline to POD 3, with median change [Q1, Q3] of -28% [-60%, 4%] vs. -39% [-56%, -23%, P⫽0.25). The median percent decrease in GFR was an estimated 9% less (95% CI: 25% less, 7% more) for the fenoldopam group than for placebo group (Fig 1a, P⫽0.25). Postoperative SCr in the two groups changed at comparable rates (P ⫽ 0.72, interaction) after adjusting for baseline creatinine (Fig 1b). The overall ratio of geometric means of post-op SCr values (including immediate post-op through POD 4) was an estimated 0.96 (95% CI: 0.78, 1.19) for fenoldopam vs. placebo (P⫽0.64). CONCLUSIONS: Fenoldopam administration did not preserve renal function in the clinical setting of renal ischemia during solitary partial nephrectomy as evidenced by GFR or SCr comparisons.

Source of Funding: Kaiser Permanente Southern California Regional Research Committee

696 THE EFFECT OF FENOLDOPAM ON RENAL FUNCTION IN SOLITARY KIDNEY PARTIAL NEPHRECTOMY Amr Fergany*, Jerome O’Hara, Steven Campbell, Kristina Kaple, Angela Bonilla, Cleveland, OH INTRODUCTION AND OBJECTIVES: Fenoldopam is a shortacting dopamine A-1 receptor agonist that decreases systemic vascular resistance while simultaneously increasing renal blood flow. A recent meta-analysis of fenoldopam trials reported an apparent decrease in the development of acute tubular necrosis, requirement for dialysis, and overall patient mortality. We tested the hypothesis that fenoldopam administration ameliorates ischemic injury by preserving glomerular filtration rate (GFR) and serum creatinine (SCr) postoperatively in solitary partial nephrectomy.

INTRODUCTION AND OBJECTIVES: Most new renal masses are now diagnosed incidentally while still small in size. Most of these small renal masses (SRM) are treated with partial nephrectomy, a procedure with a significant amount of complications. Multiple series have reported a high proportion (up to 46%) of benign histology after surgical resection of these small renal masses. There is a clear need for accurate prediction of benign disease. Multiple preoperative factors such as sex, age, tumor size and location have been implicated in the prediction of benign histology. We aimed to apply classification tree algorithms to discriminate between benign and malignant histology when SRMs are being evaluated preoperatively. METHODS: A classification tree was developed based on a cohort of 385 patients who underwent surgical management for presumed renal cell carcinoma ⬍ 5cm in largest diameter at our institution between July 1st 2001 and June 30th 2010. Age, sex, tumor size (largest bi-dimensional diameter in cm), tumor location (central vs. peripheral), degree of endophytic component (1-100%) and tumor axis location (according to the three renal axes) were used to develop the model. RESULTS: The overall incidence of benign disease was 11.4%. The classification tree partitioned the subjects into seven disjoint sets differing in risk of benign histology based on a minimum of one and a maximum of four predictors; symptoms at diagnosis, % endophytic, tumor size, and patient age. As an example in one branch of the tree, patients who had tumors that were less than 5.7cc (n⫽84) and less than 45% endophytic (n⫽19) had a 52.6% chance of having a benign tumor. Conversely, 100% of patients with tumors larger than 5.7cc (311), who were symptomatic at diagnosis (207), and who’s tumors were greater than 85% endophytic (40) had a malignant renal mass on final histology. The cross-validated estimate accuracy of the model is 87.8% with a 95% CI (85.8, 92.7).