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1807 IMPLICATIONS OF ACUTE KIDNEY INJURY AFTER ROBOTIC PARTIAL NEPHRECTOMY FOR LONG TERM RENAL FUNCTION
Vol. 189, No. 4S, Supplement, Tuesday, May 7, 2013
THE JOURNAL OF UROLOGY姞
and 73.5% and 96.9% for African-Americans. The proportion undergoing NSM vs. PN or RN was higher for African-Americans than for Caucasians (16.7% vs. 9.9%, PR 1.68, p⬍0.001) but proportions were similar for PN vs. RN (31.5% vs. 28.3%, p⫽0.125). For NSM, AfricanAmericans had a higher odds of NSM (OR 2.00 [1.57-2.55], p⬍0.001), which has decreased over time, but there was no difference for sex (p⫽0.904). For PN, female sex had a lower odds of PN use compared to males (OR 0.86 [0.77-0.96], p⫽0.009) but no difference by race was observed (p⫽0.258). CONCLUSIONS: Among Medicare beneficiaries, no racial disparities were evident in the use of PN over RN. Underutilization of PN was seen in females and is consistent with previous research. A significant disparity exists with underutilization of surgery in African-Americans even after accounting for age, sex, and comorbidity index. Access to healthcare and provider awareness are potential contributors, and disparities may be even more pronounced in uninsured populations. Source of Funding: None
1807 IMPLICATIONS OF ACUTE KIDNEY INJURY AFTER ROBOTIC PARTIAL NEPHRECTOMY FOR LONG TERM RENAL FUNCTION Brandy Hood*, Spencer Krane, Theodore Manny, Ashok Hemal, Winston-Salem, NC INTRODUCTION AND OBJECTIVES: Nephron-sparing surgery has become the preferred management option for small renal masses offering comparable oncologic outcomes with preservation of renal function. Robotic partial nephrectomy (RPN) offers several advantages over a pure laparoscopic in terms of technical ease, however functional outcomes are still being established. We describe our experience regarding long-term renal function outcomes, specifically examining those patients with acute kidney injury (AKI) in the immediate postoperative period. METHODS: We performed a retrospective review of the records of 253 consecutive patients undergoing RPN for small renal masses from January 2008 to July 2012. We assessed preoperative and postoperative glomerular filtration rate (GFR) as calculated by the Modification of Diet in Renal Disease (MDRD) formula. Patients with AKI at discharge, defined as ⬎25% decrease in GFR by RIFLE criteria, were compared with those without AKI. GFR in these two cohorts were also compared after long-term follow-up. Student’s t-test was used to evaluate significance of all comparisons. RESULTS: Of 253 patients undergoing RPN, 48 had AKI at discharge from the hospital. This cohort had significantly higher mean preoperative GFR (93 ml/ min, SD ⫽ 26 vs 78 ml/min, SD ⫽ 23; p ⫽ 0.0005) and significantly greater mean decrease in GFR at discharge from the hospital (-34%, SD ⫽ 6.7 vs -17%, SD ⫽ 17; p ⬍ 0.0001) compared to the non-AKI cohort. 172 patients had GFR calculations ⬎ 1 month post operatively (35 AKI, 137 non-AKI). Mean follow-up was 13 months for both cohorts, and at that time the AKI group continued to have significantly greater decrease in baseline GFR compared to non-AKI (-23%, SD 18 vs -6%, SD ⫽ 22; p ⬍0.0001). There was no significant difference in GFR at 13 months (71 ml/min, SD ⫽ 22 vs 72 ml/min, SD ⫽ 26; p ⫽ 0.84). These findings are summarized in Table 1 along with patient characteristics. CONCLUSIONS: Patients with AKI immediately following RPN having greater long-term loss of renal function compared to those without AKI, but reach a similar endpoint. Table 1. Characteristics of AKI vs Non-AKI Patients after Robotic Partial Nephrectomy Non-AKI at Total AKI at Discharge P-value* Variables Population Discharge Mean age (SD) 58.9 (12.8) 58 (12.4) 59 (12.9) 0.47 Mean BMI (SD)
30 (5.8)
32 (6.7)
30 (5.5)
0.08
Mean largest tumor size on CT (SD)
2.8cm (1.2)
3.2cm (1.2)
2.7 (1.2)
0.03
Total Variables Population RENAL Nephrometry score
AKI at Discharge
Non-AKI at Discharge
High (⬎10)
6%
8%
6%
Med (7-9)
32%
38%
31%
Low (4-6)
62%
54%
43%
No clamp
7%
17%
Arterial clamp only
26%
43%
Clamping method
Arterial and venous clamp
e743
P-value* 0.45
0.003
67%
40%
Mean preoperative GFR (SD)
93 ml/min (26)
78 ml/min (23)
0.0005
Mean percent change in GFR at discharge (SD)
-34% (6.7)
-17% (17)
⬍ 0.0001
Mean GFR atmost recent followup**
71 ml/min (22)
72 ml/min (26)
0.84
Mean percent change at most recent follow-up -23% (18) -6% (22) ⬍ 0.0001 *Compares AKI and Non-AKI only; **mean follow-up 13 months in both AKI and non-AKI groups; SD ⫽ standard deviation.
Source of Funding: None
1808 THE IMPACT OF PERI-RENAL FAT ON SURGICAL OUTCOMES FOLLOWING PARTIAL NEPHRECTOMY FOR RENAL CELL CARCINOMA Tariq A. Khemees*, Firas Petros, Ahmad Shabsigh, David S. Sharp, Geoffrey N. Box, Columbus, OH INTRODUCTION AND OBJECTIVES: The impact of obesity on surgical outcomes has been well studied. Most have used Body Mass Index (BMI) as the standard marker for obesity, however; BMI does not always correlate with the amount of peri-nephric fat. Significant amounts of peri-nephric fat have been noted to increase the difficulty of performing renal surgery, but the influence has not been well studied in partial nephrectomy. We aimed to investigate the impact of three obesity measures, peri-renal fat, subcutaneous fat (SQF) and BMI, on the surgical outcomes of partial nephrectomy for renal cell carcinoma (RCC). METHODS: We reviewed patients with RCC who had undergone a partial nephrectomy with a previously calculated RENAL nephrometry score at our institution. For each patient, a preoperative imaging study (CT or MRI) was used to measure the peri-renal fat distance on the anterior, lateral and posterior aspect of the kidney. SQF was also measured on the anterior, lateral and posterior aspect of the body. Pearson correlation was used to assess the correlation of these measurements with the patients’ BMI. Multiple regression models were used to assess which obesity measures had higher impact on surgical outcomes. RESULTS: 240 patients met the inclusion criteria. Mean BMI was 31.6 Kg/m2 (range 18.2-59.4 Kg/m2). Mean tumor nephrometry score was 6.5 (range, 4-11) with a mean tumor size of 3.5 cm (range, 1-8 cm). Mean total peri-renal fat distance (sum of the three measurements) was 48.4 mm (range, 8.5-128.4 mm) and mean total SQF fat distance was 66.3 mm (range, 12.5-161.1 mm). A patient’s BMI expressed a stronger correlation with SQF than with the peri-renal fat (correlation coefficient 0.61 vs. 0.36, both p-value ⬍0.001). However, on multivariate regression analysis controlling for the tumor size and nephrometry score, peri-renal fat distance (both total and individual measurements) was an independent predictor of increased operative time, incidence of positive margins and a higher rate of 30-day postoperative complications. BMI and SQF only correlated with increased operative time.
THE JOURNAL OF UROLOGY姞
and 73.5% and 96.9% for African-Americans. The proportion undergoing NSM vs. PN or RN was higher for African-Americans than for Caucasians (16.7% vs. 9.9%, PR 1.68, p⬍0.001) but proportions were similar for PN vs. RN (31.5% vs. 28.3%, p⫽0.125). For NSM, AfricanAmericans had a higher odds of NSM (OR 2.00 [1.57-2.55], p⬍0.001), which has decreased over time, but there was no difference for sex (p⫽0.904). For PN, female sex had a lower odds of PN use compared to males (OR 0.86 [0.77-0.96], p⫽0.009) but no difference by race was observed (p⫽0.258). CONCLUSIONS: Among Medicare beneficiaries, no racial disparities were evident in the use of PN over RN. Underutilization of PN was seen in females and is consistent with previous research. A significant disparity exists with underutilization of surgery in African-Americans even after accounting for age, sex, and comorbidity index. Access to healthcare and provider awareness are potential contributors, and disparities may be even more pronounced in uninsured populations. Source of Funding: None
1807 IMPLICATIONS OF ACUTE KIDNEY INJURY AFTER ROBOTIC PARTIAL NEPHRECTOMY FOR LONG TERM RENAL FUNCTION Brandy Hood*, Spencer Krane, Theodore Manny, Ashok Hemal, Winston-Salem, NC INTRODUCTION AND OBJECTIVES: Nephron-sparing surgery has become the preferred management option for small renal masses offering comparable oncologic outcomes with preservation of renal function. Robotic partial nephrectomy (RPN) offers several advantages over a pure laparoscopic in terms of technical ease, however functional outcomes are still being established. We describe our experience regarding long-term renal function outcomes, specifically examining those patients with acute kidney injury (AKI) in the immediate postoperative period. METHODS: We performed a retrospective review of the records of 253 consecutive patients undergoing RPN for small renal masses from January 2008 to July 2012. We assessed preoperative and postoperative glomerular filtration rate (GFR) as calculated by the Modification of Diet in Renal Disease (MDRD) formula. Patients with AKI at discharge, defined as ⬎25% decrease in GFR by RIFLE criteria, were compared with those without AKI. GFR in these two cohorts were also compared after long-term follow-up. Student’s t-test was used to evaluate significance of all comparisons. RESULTS: Of 253 patients undergoing RPN, 48 had AKI at discharge from the hospital. This cohort had significantly higher mean preoperative GFR (93 ml/ min, SD ⫽ 26 vs 78 ml/min, SD ⫽ 23; p ⫽ 0.0005) and significantly greater mean decrease in GFR at discharge from the hospital (-34%, SD ⫽ 6.7 vs -17%, SD ⫽ 17; p ⬍ 0.0001) compared to the non-AKI cohort. 172 patients had GFR calculations ⬎ 1 month post operatively (35 AKI, 137 non-AKI). Mean follow-up was 13 months for both cohorts, and at that time the AKI group continued to have significantly greater decrease in baseline GFR compared to non-AKI (-23%, SD 18 vs -6%, SD ⫽ 22; p ⬍0.0001). There was no significant difference in GFR at 13 months (71 ml/min, SD ⫽ 22 vs 72 ml/min, SD ⫽ 26; p ⫽ 0.84). These findings are summarized in Table 1 along with patient characteristics. CONCLUSIONS: Patients with AKI immediately following RPN having greater long-term loss of renal function compared to those without AKI, but reach a similar endpoint. Table 1. Characteristics of AKI vs Non-AKI Patients after Robotic Partial Nephrectomy Non-AKI at Total AKI at Discharge P-value* Variables Population Discharge Mean age (SD) 58.9 (12.8) 58 (12.4) 59 (12.9) 0.47 Mean BMI (SD)
30 (5.8)
32 (6.7)
30 (5.5)
0.08
Mean largest tumor size on CT (SD)
2.8cm (1.2)
3.2cm (1.2)
2.7 (1.2)
0.03
Total Variables Population RENAL Nephrometry score
AKI at Discharge
Non-AKI at Discharge
High (⬎10)
6%
8%
6%
Med (7-9)
32%
38%
31%
Low (4-6)
62%
54%
43%
No clamp
7%
17%
Arterial clamp only
26%
43%
Clamping method
Arterial and venous clamp
e743
P-value* 0.45
0.003
67%
40%
Mean preoperative GFR (SD)
93 ml/min (26)
78 ml/min (23)
0.0005
Mean percent change in GFR at discharge (SD)
-34% (6.7)
-17% (17)
⬍ 0.0001
Mean GFR atmost recent followup**
71 ml/min (22)
72 ml/min (26)
0.84
Mean percent change at most recent follow-up -23% (18) -6% (22) ⬍ 0.0001 *Compares AKI and Non-AKI only; **mean follow-up 13 months in both AKI and non-AKI groups; SD ⫽ standard deviation.
Source of Funding: None
1808 THE IMPACT OF PERI-RENAL FAT ON SURGICAL OUTCOMES FOLLOWING PARTIAL NEPHRECTOMY FOR RENAL CELL CARCINOMA Tariq A. Khemees*, Firas Petros, Ahmad Shabsigh, David S. Sharp, Geoffrey N. Box, Columbus, OH INTRODUCTION AND OBJECTIVES: The impact of obesity on surgical outcomes has been well studied. Most have used Body Mass Index (BMI) as the standard marker for obesity, however; BMI does not always correlate with the amount of peri-nephric fat. Significant amounts of peri-nephric fat have been noted to increase the difficulty of performing renal surgery, but the influence has not been well studied in partial nephrectomy. We aimed to investigate the impact of three obesity measures, peri-renal fat, subcutaneous fat (SQF) and BMI, on the surgical outcomes of partial nephrectomy for renal cell carcinoma (RCC). METHODS: We reviewed patients with RCC who had undergone a partial nephrectomy with a previously calculated RENAL nephrometry score at our institution. For each patient, a preoperative imaging study (CT or MRI) was used to measure the peri-renal fat distance on the anterior, lateral and posterior aspect of the kidney. SQF was also measured on the anterior, lateral and posterior aspect of the body. Pearson correlation was used to assess the correlation of these measurements with the patients’ BMI. Multiple regression models were used to assess which obesity measures had higher impact on surgical outcomes. RESULTS: 240 patients met the inclusion criteria. Mean BMI was 31.6 Kg/m2 (range 18.2-59.4 Kg/m2). Mean tumor nephrometry score was 6.5 (range, 4-11) with a mean tumor size of 3.5 cm (range, 1-8 cm). Mean total peri-renal fat distance (sum of the three measurements) was 48.4 mm (range, 8.5-128.4 mm) and mean total SQF fat distance was 66.3 mm (range, 12.5-161.1 mm). A patient’s BMI expressed a stronger correlation with SQF than with the peri-renal fat (correlation coefficient 0.61 vs. 0.36, both p-value ⬍0.001). However, on multivariate regression analysis controlling for the tumor size and nephrometry score, peri-renal fat distance (both total and individual measurements) was an independent predictor of increased operative time, incidence of positive margins and a higher rate of 30-day postoperative complications. BMI and SQF only correlated with increased operative time.