Predicting postoperative renal insufficiency in patients undergoing nephrectomy for renal malignancy: assessment by renal scintigraphy using 99mtechnetium-mercaptoacetyltriglycine

PURPOSE: We performed Tc-mercaptoacetyltriglycine (MAG3) renal scintigraphy in patients with renal malignancy to evaluate the function of each renal unit before and after nephrectomy to see if postoperative functional deterioration could be predicted based on scintigraphy results and creatinine clearance. MATERIALS AND METHODS: A total of 22 men and 13 women with renal malignancy, including 32 with renal cell carcinoma and 3 with urothelial cancer, were prospectively enrolled in this study. Average patient age was 64.3 years (median 65, range 43 to 88). All patients underwent MAG3 renal scintigraphy before and after unilateral nephrectomy. At the same time serum creatinine and endogenous creatinine clearance were determined. RESULTS: Mean serum creatinine was 0.93 mg/dl before and 1.31 after nephrectomy (p <0.0001). Preoperative endogenous creatinine clearance was 70.8 ml per minute per 1.73 m, which decreased to 49.0 ml per minute per 1.73 m after nephrectomy (p <0.0001). Mean MAG3 clearance of the remaining kidney increased 35.1% above baseline from 156.5 to 211.5 ml per minute per 1.73 m following nephrectomy. Spearman rank core analysis revealed that preoperative MAG3 clearance of the remaining kidney significantly correlated with postoperative creatinine clearance (r = 0.596, p = 0.0005). Preoperative MAG3 clearance of the remaining kidney more than 130 ml per minute per 1.73 m coincided with postoperative creatinine clearance above 40 ml per minute per 1.73 m. CONCLUSIONS: MAG3 renal scintigraphy may be useful for predicting renal insufficiency after nephrectomy. The findings in this study suggest that preoperative MAG3 clearance of the remaining kidney less than 130 ml per minute per 1.73 m is a risk factor for postoperative renal insufficiency.     

Balloon occlusion and hypothermic perfusion of the renal artery in laparoscopic partial nephectomy

Objectives: We describe our initial experience with renal arterial catheterization for temporary balloon occlusion of renal artery and hypothermic perfusion during laparoscopic partial nephectomy and compare the preoperative and postoperative nephron function. Methods: Fifteen patients received laparoscopic partial nephrectomy from September 2005 to December 2006. During the operations, the balloons of the arterial catheters were filled with distilled water to achieve pedicle control. Chilled Ringers lactate was continuously infused into the catheters for renal hypothermia. Postoperative Tc‐99m diethylenetriamine pentaacetic acid (DTPA) renal scintigraphies were carried out to estimate differential renal function. The volumes of the renal tumors, tumor‐bearing and contralateral kidneys from CT scans were measured using commercial software. Estimated creatinine clearance was calculated with Cockroft Gault formula. Results: All procedures were successfully completed. Mean tumor size was 18.4 mL (range 2.14 to 59.0). Estimated mean intraoperative blood loss was 287 mL (range minimal to 1200). Mean estimated creatinine clearance per unit volume of functional renal parenchyma did not change statistically after the operation. Multiple regression analysis revealed that ischemic time was a significant variable which correlated with the value of lost total estimated creatinine clearance of the tumor bearing kidney. Conclusions: The initial experience shows that renal arterial catheterization for temporary balloon occlusion and hypothermic perfusion of the renal artery in laparoscopic partial nephectomy is safe, feasible and effective. The postoperative kidney function measured by mean estimated creatinine clearance per unit of functional renal volume was similar to the preoperative measurement.     

Influence of renal function on serum and urinary heart fatty acid-binding protein levels.

BACKGROUND: Serum heart fatty acid-binding protein (H-FABP) has been reported to be a sensitive and early indicator of myocardial damage. However, circulating H-FABP may be cleared considerably from kidney, similar to that found for myoglobin. Therefore, the possibility exists that any change in renal function affects serum H-FABP concentration, and thus leads to erroneous interpretation. To evaluate the influence of renal function on H-FABP levels, we conducted a prospective study. METHODS: Nineteen patients undergoing isolated primary coronary artery bypass grafting were enrolled in this study. The patients were classified by the preoperative creatinine clearance into two groups: the control group (n=12); patients with creatinine clearance of 40 mL/min or greater, and the renal dysfunction group (n=7); patients with creatinine clearance of less than 40 mL/min. Serum H-FABP, CK-MB, troponin-T and urinary H-FABP levels were measured perioperatively. RESULTS: None of the patients had perioperative myocardial infarction. No significant differences were found in CK-MB and troponin-T levels between the groups. The renal dysfunction group resulted in significantly (p<0.05) higher serum H-FABP levels and lower urinary H-FABP levels than those in the control group, postoperatively. The creatinine clearance correlated inversely with the peak levels of serum H-FABP (r=-0.75, p=0.0001) and correlated with the peak levels of urinary H-FABP (r=0.64, p=0.003). CONCLUSIONS: The results indicate that the kidneys play an important role in the clearance of serum H-FABP. Thus, caution must be taken in interpreting this marker for myocardial damage during cardiac surgery in patients with renal dysfunction.     

Prognostic nomogram for renal insufficiency after radical or partial nephrectomy

PURPOSE: We analyzed prognostic factors to predict renal insufficiency after partial or radical nephrectomy. We developed and performed internal validations of a postoperative nomogram for this purpose. We used a prospectively updated renal tumor database of more than 1,500 patients. MATERIALS AND METHODS: From July 1989 to October 2003, 161 partial nephrectomies and 857 radical nephrectomies performed at Memorial Sloan-Kettering Cancer Center for renal cortical tumors were analyzed. Computerized tomography images were reviewed by a single radiologist. Kidney volume was calculated using the ellipsoid formula, V = L1 x L2 x L3 x pi/6, where V represents volume and L represents length. Renal insufficiency was defined by 2 serum creatinine values greater than 2.0 mg/dl at least 1 month postoperatively. Tumor histology was not an exclusion criterion and yet we excluded cases of bilateral synchronous disease. Prognostic variables were preoperative serum creatinine, American Society of Anesthesiologists score, percent change in kidney volume after surgery, and patient age and sex. RESULTS: Renal insufficiency was noted in 105 of the 857 patients with radical nephrectomy (12.3%) and in 6 of the 161 with partial nephrectomy (3.7%) studied. Patients had a median followup of 21.2 months (maximum 157.9). The 7-year probability of freedom from renal insufficiency in the cohort was 79.1% (95% CI 74.6 to 83.6). The nomogram was designed based on a Cox proportional hazards regression model. Following internal statistical validation nomogram predictions appeared accurate and discriminating with a concordance index of 0.835. CONCLUSIONS: A nomogram was developed that can predict the 7-year probability of renal insufficiency in patients undergoing radical or partial nephrectomy.     

The value of quantitative 99M technetium dimercaptosuccinic acid renal scintigraphy for predicting postoperative renal insufficiency in patients undergoing nephrectomy

PURPOSE: Radical nephrectomy is a routine urological practice. However, little is known about the use of dimercapto-succinic acid (DMSA) scan to evaluate compensatory changes after surgery and its ability to identify patient at risk for postoperative chronic renal failure or insufficiency. We predicted remaining kidney function using DMSA scan and serum creatinine. MATERIALS AND METHODS: A total of 42 patients were enrolled in the study. All underwent DMSA scan before surgery and in 38 DMSA scan was done after unilateral nephrectomy. Serum creatinine was determined before and 1 year after surgery. The Student t test was used to determine statistical significance. Spearman rank core analysis was used to evaluate the association of calculated creatinine clearance time after surgery and renal absolute uptake before surgery. We performed 1-way ANOVA comparison of the means to determine the influence of age distribution on kidney hypertrophy and the increase in kidney uptake. RESULTS: Average patient age was 61.5 years. Baseline mean creatinine clearance time was 71.5 ml. per minute, which decreased to 58.6 ml. per minute after nephrectomy (p <0.0001). Before surgery DMSA scan of the remaining kidney demonstrated an absolute uptake of 4.2% higher than that in the resected kidney (13.5% versus 9.35%, p = 0.0008). After nephrectomy the remaining kidney had an average increase of 3.9% of mean absolute uptake (17.7% versus 13.8%, p = 0.0001). Spearman rank core analysis demonstrated an association of higher preoperative absolute uptake in the remaining kidney with postoperatively high creatinine clearance time (r = 0.458, p = 0.003). Furthermore, 75% of patients with postoperative creatinine clearance time less than 40 ml. per minute presented with a preoperative absolute uptake of lower than 11% in the remaining kidney. In contrast, 75% of those with a postoperative creatinine clearance time of higher than 40 ml. per minute had a preoperative absolute uptake of higher than 11%. CONCLUSIONS: A preoperative absolute uptake of lower than 11% in the remaining kidney was a significant risk factor for postoperative chronic renal insufficiency.     

Rapid communication: chronic renal insufficiency after laparoscopic partial nephrectomy and radical nephrectomy for pathologic t1a lesions

PURPOSE: To report the prevalence of new-onset renal insufficiency in patients undergoing laparoscopic partial nephrectomy (LPN) as compared to laparoscopic radical nephrectomy (LRN) for pathologic T1a lesions. PATIENTS AND METHODS: Forty-eight patients and 37 patients with a normal contralateral kidney, preoperative creatinine (Cr) concentration <2 mg/dL, and tumors <4 cm in size underwent LPN and LRN, respectively. Glomerular filtration rate (GFR) was estimated using an abbreviated Modification of Diet in Renal Disease (MDRD) equation. Cr concentrations and GFR values were analyzed in patients undergoing LPN or LRN. Statistical analysis was performed with two-tailed t-test assuming unequal variances, to establish significance by P < 0.05. RESULTS: Preoperative Cr and GFR was equivalent in the LPN and LRN groups (0.9 mg/dL and 90 mL/min). At last follow-up (mean 205 and 233 days in the LPN and LRN groups, respectively) mean creatinine was 1.03 +/- 0.3 mg/dL v 1.4 mg/dL +/- 0.3 (P = 0.0002). Estimated GFR was 79 +/- 22 mL/min per 1.73 m2 v 55 +/- 14 mL/min per 1.73 m2 (range 31-91 mL/min per 1.73 m2; P < .0001) in the LPN and LRN groups, respectively. One patient in the LPN group and three patients in the LRN group had clinical renal insufficiency as defined by Cr > 2.0 mg/dL. Subclinical renal insufficiency (Cr < 2.0, but calculated GFR <60 mL/min per 1.73 m2) was present in 57% of the LRN patients v 15% of the LPN patients. CONCLUSIONS: LPN preserves renal function more effectively than LRN for pathologic T1a lesions. Subclinical renal insufficiency (GFR <60 mL/min per 1.73 m2) was present in the majority of patients undergoing radical nephrectomy in our series. Importantly, this series included the use of warm ischemia in all cases.     

Surgical management of renal tumors 4 cm. or less in a contemporary cohort

PURPOSE: We evaluated a patient cohort with renal tumors 4 cm. or less treated with partial or radical nephrectomy. We compared patient and tumor characteristics, and survival in these 2 groups. MATERIALS AND METHODS: We retrospectively analyzed the records of 670 patients with a median age of 63 years treated surgically for renal cell carcinoma between July 31, 1989 and July 31, 1997. Renal tumors 4.0 cm. or less were noted in 252 patients (38%) who underwent a total of 262 procedures, including 183 radical (70%) and 79 partial (30%) nephrectomies. Ten patients required 2 operations each because of bilateral renal cell carcinoma. Median followup was 40 months. We compared clinicopathological parameters in the partial and radical nephrectomy groups using chi-square or Wilcoxon analysis as appropriate. Survival analysis was determined by the log rank test and Cox regression model. RESULTS: The partial and radical nephrectomy groups were comparable with respect to gender ratio, tumor presentation, histological classification, pathological stage and complication rate. Median tumor size was 2.5 and 3.0 cm. in the partial and radical nephrectomy groups, respectively (p = 0.0001). Resection was incomplete in 1 patient (1.3%) in the partial and none in the radical nephrectomy group. There was no local recurrence after either procedure, and no significant difference in disease specific, disease-free and overall survival (p = 0.98, 0.23 and 0.20, respectively). CONCLUSIONS: Patients with a small renal tumor have similar perioperative morbidity, pathological stage and outcome regardless of treatment with partial or radical nephrectomy. Therefore, partial nephrectomy remains a safe alternative for tumors of this size.     

Unilateral nephrectomy and glomerular solute transport in the dog

The influence of compensatory hyperfunction that occurs following unilateral nephrectomy on glomerular solute transport was determined in awake, unanesthetized dogs by renal clearance studies. Two groups of dogs were studied using different test solutes: group I (N = 5) using inulin, iothalamate, creatinine and sodium p-aminohippurate; and group II (N = 6) using creatinine, neutral dextran (3000 to 50,000 daltons) and sodium p-aminohippurate. Compensatory hyperfunction, as assessed by the increase in creatinine clearance per kidney, was 43 +/- 7% and 39 +/- 11% in the group I and II dogs, respectively. The inulin to creatinine and iothalamate to creatinine clearance ratios in the group I dogs were 0.93 +/- 0.07 and 1.00 +/- 0.04 before unilateral nephrectomy. The respective values after unilateral nephrectomy of 0.86 +/- 0.04 and 0.89 +/- 0.05 were lower but not statistically different. In the group II dogs, dextran to creatinine clearance ratios (dextran fractional clearance) over the molecular weight range studied also did not change significantly following unilateral nephrectomy. The magnitude of the change in dextran fractional clearance following unilateral nephrectomy was qualitatively consistent with that predicted by previous models of glomerular macromolecular transport based on membrane pore theory. A lack of quantitative agreement with these models, however, precluded a calculation of the changes in glomerular functional parameters following unilateral nephrectomy. Significant alterations in fractional clearance for neutral macromolecules do not occur following unilateral nephrectomy in the dog.     

Effect of diet on creatinine clearance and excretion in young and elderly healthy subjects and in patients with renal disease.

Thirty-seven young healthy subjects with normal renal function were studied to assess the quantitative effect of protein intake on creatinine clearance. A standard 24-h urine collection and blood sample at the end of the collection were obtained for creatinine and urea concentrations. Correlations between creatinine clearance and urinary urea nitrogen excretion (r = 0.8; P less than 0.0001) and calculated protein intake (r = 0.8; P less than 0.0001) were observed. A significant relationship between creatinine clearance and urea nitrogen excretion was also demonstrated in 28 elderly healthy subjects and 33 patients with renal disease. To demonstrate a cause and effect between urea nitrogen excretion and creatinine clearance in healthy subjects, 18 of the 37 healthy subjects repeated the 24-h urine collection and blood sample after ingesting 5 g of urea in addition to their usual diet. Mean urinary urea nitrogen excretion increased from a mean value of 9.8 +/- 4.0 to 11.8 +/- 4.0 g/day. There was a strong correlation between the changes in urea nitrogen excretion and the changes in creatinine clearance. In acute studies with oral protein loading, there was a significant correlation between creatinine clearance and urinary urea nitrogen excretion. It was concluded that protein intake has a direct and quantitative effect on creatinine clearance in healthy subjects. In normal humans, it is likely that GFR is not a fixed function. Thus, a low creatinine clearance is not a categorical sign of renal disease. A low creatinine clearance adjusted for urea nitrogen excretion may be a useful clinical tool to assess renal function.     

Partial nephrectomy using microwave tissue coagulator--application for laparoscopic operation

We report our clinical findings on 12 tumors (11 patients) successfully resected by partial nephrectomy with a microwave tissue coagulator (MTC) without renal pedicle clamping, including laparoscopic operation in 4 patients. All patients presented with a renal tumor detected incidentally by ultrasonography or computed tomography. The mean size of renal tumor was 1.9 (range 0.8-3.4) cm. Pathological diagnosis was renal cell carcinoma in 9 tumors and hemorrhagic cyst in 3 tumors. Mean operative time was 249 minutes. Mean blood loss was 183 ml in cases with a laparoscopic operation, that was statistically less than 486 ml in cases with an open operation (p<0.05), and 376 ml in all cases. There was no significant change in the creatinine clearance of cases with laparoscopic operation, compared with that of cases with an open operation. There were no other serious complications postoperatively. These findings suggested that partial nephrectomy with the MTC can be safely and successfully carried out while sparing renal function. Moreover, partial nephrectomy with the MTC for a laparoscopic operation may provide these patients with more benefits.     

Partial nephrectomy for renal cell carcinoma using a microwave tissue coagulator--postoperative recurrence and renal function

Nowadays, partial nephrectomy is often selected for treatment of small renal cell carcinoma (RCC) because T1a RCC shows a favorable prognosis with a 5-year overall-survival rate exceeding 90%. To determine the methodological usefulness and treatment outcome of partial nephrectomy using microwave tissue coagulator (MTC), we evaluated our series of 121 patients (124 kidneys) with T1 RCC who underwent this procedure. Ninety-nine patients were elective and 22 patients were imperative cases. This procedure was indicated for asymptomatic solitary RCC; < or =4 cm in diameter in elective cases or < or =5 cm in imperative cases, expanding outward with a clear capsule, and showing neither renal pelvis nor renal sinus invasion. The median operation time was 150 minutes and the median blood loss was 217 ml. Eight patients needed transfusion, and conservative therapy cured 4 patients of postoperative urine leakage successfully. Three patients underwent early secondary nephrectomy due to multiple RCCs, invasive spindle cell carcinoma, or prolongation of urine leakage. No significant deterioration of renal function by creatinine clearance (Ccr) was observed, and postoperative Ccr could be precisely predicted from preoperative serum creatinine value and the renal parenchymal volume estimated with 3-dimensinal image reconstruction. Five-year overall-survival rate was 91% at the mean follow-up of up to 37.9 months and 107 patients were alive without disease. One patient showed local recurrence 2 years later and underwent radical nephrectomy. We believe that non-ischemic partial nephrectmy using MTC is a simple and reliable nephron-sparing surgery for small RCC in respect of postoperative recurrence and preservation of renal function.     

No detrimental effect on renal function during long-term use of fluvastatin in renal transplant recipients in the Assessment of Lescol in Renal Transplantation (ALERT) study

BACKGROUND: Concerns have recently been raised regarding a potential harmful effect of statins on renal function. This study investigated the effect of fluvastatin treatment on renal function in renal transplant recipients enrolled in the Assessment of Lescol in Renal Transplantation (ALERT) trial. METHODS: ALERT was a randomized, double-blind, placebo-controlled study of the effect of fluvastatin, 40-80 mg daily (n = 1050) or placebo (n = 1052) on cardiac and renal outcomes in renal transplant recipients over a follow-up period of five to six years. The incidence of graft loss, changes in serum creatinine, calculated creatinine clearance and proteinuria, and the incidence of renal adverse events (AEs) were assessed in both treatment groups. RESULTS: Fluvastatin treatment in ALERT had no significant effect compared with placebo on renal function, assessed by serum creatinine (overall adjusted mean +/- SEM: fluvastatin, 175.4 +/- 2.20 micromol/L; placebo, 172.7 +/- 2.20 micromol/L; p = 0.39), creatinine clearance (fluvastatin, 55.3 +/- 0.30 mL/min; placebo, 55.8 +/- 0.30 mL/min; p = 0.26) or proteinuria (fluvastatin, 0.58 +/- 0.03 g/24 h; placebo, 0.53 +/- 0.03 g/24 h; p = 0.31). There were no significant differences between treatment groups when the 283 patients suffering graft loss were excluded from the analysis. Fluvastatin also had no detrimental effect on creatinine clearance or proteinuria in the subgroup of 340 diabetic patients without graft loss in ALERT. No notable differences in the rate of renal or musculoskeletal AEs were observed between fluvastatin and placebo groups. CONCLUSIONS: Fluvastatin had no detrimental effect on renal function, or the risk of renal AEs, in renal transplant recipients with or without diabetes enrolled in ALERT. Fluvastatin treatment for the prevention of cardiac events may therefore be used without fear of jeopardizing renal function.     

Risk of renal insufficiency in African-Americans after radical nephrectomy for kidney cancer

PURPOSE: We conducted a retrospective review to evaluate the change in serum creatinine in an African-American population undergoing radical nephrectomy. MATERIALS AND METHODS: Race, and preoperative and follow-up creatinine data were extracted from the medical records of all patients who underwent radical nephrectomy performed by a single surgeon. Patients were classified as African-American or black and non-African-American. The non-African-American group included Caucasian, Asian, and Hispanic patients. RESULTS: A total of 22 African-American and 19 non-African-American patients were studied. Mean preoperative creatinine was 1.3 mg/dL in African-American patients and 1.1 in non-African-American patients (P = 0.07). Average follow-up creatinine was 1.7 in the African-Americans, with a mean change in creatinine of 0.4, compared to the non-African-Americans, in which mean follow-up creatinine was 1.3 (P = 0.004) with a mean change of 0.2 (P = 0.048). Average follow-up creatinine was higher in African-American hypertensive (2.0 mg/dl) compared with non-African-American hypertensive patients (1.4 mg/dl; P = 0.002). Average change in creatinine was also higher in African-American hypertensive versus non-African-American hypertensive patients (0.6 vs. 0.2 mg/dl, P = 0.048). There were no racial differences seen in normotensive cases. Average follow-up was 9.7 months for African-American and 11.6 months for non-African-American patients. CONCLUSIONS: Our data indicate that race may be a significant risk factor for renal deterioration after radical nephrectomy.     

Associations between radiographic characteristics and change in renal function following partial nephrectomy using 24-hour creatinine clearance

Background

Radiographic characteristics may be associated with the degree of renal function preservation following partial nephrectomy. The purpose of this study was to determine the impact of preoperative radiographic variables on change in renal function using 24-hour urine creatinine clearance (uCrCl).

Methods

Patients with partial nephrectomy performed from November 2003 to 2008 were enrolled in the study. Serum creatinine and 24-hour urine was collected preoperatively and at 3, 6 and 12 months postoperatively. Computed tomography or magnetic resonance imaging was used to determine tumour size, tumour location and renal volume.

Results

Of the 36 patients, median age was 62 (range 30–78) and 21 (58%) were male. The mean tumour diameter was 2.8±1.4 cm. Twenty-two (61%) tumours were located at the renal pole and 11 (31%) were endophytic. Overall, mean preoperative uCrCl was 88.8±34.2 mL/min and mean postoperative uCrCl was 82.8±33.6 mL/min (6.8%; p < 0.01). On multivariable analysis, no single characteristic was associated with a clinically prohibitive decrease in renal function (−9.4% if endophitic, p = 0.06; −0.57% per cm diameter, p = 0.73; and −6.9% if located at the renal pole, p = 0.15). The total renal volume was also not significantly associated with renal function change (−1.1% per 100 cc, p = 0.86).     

Creatinine clearance and risk of early mortality in patients undergoing coronary artery bypass grafting

OBJECTIVES: We sought to evaluate renal function assessed on the basis of calculated creatinine clearance as a predictor of early mortality and postoperative complications in patients undergoing coronary artery bypass grafting and to assess whether calculated creatinine clearance is superior to serum creatinine concentration in predicting early death postoperatively. METHODS: Six thousand seven hundred eleven consecutive patients without dialysis-dependent renal insufficiency undergoing a first isolated coronary artery bypass grafting were included. Preoperative serum creatinine concentrations and creatinine clearance calculated by using the Cockroft-Gault formula were related to mortality within 30 days postoperatively. RESULTS: There were 136 early deaths. After adjustment for age and other confounders in multivariate analyses, moderate (calculated creatinine clearance 30-60 mL/min) and severe (calculated creatinine clearance < 30 mL/min) renal insufficiency predicted early mortality (odds ratio of 2.4 [95% confidence interval, 1.2-4.8] and odds ratio of 4.8 [95% confidence interval], 1.6-13.9, respectively) compared with normal (calculated creatinine clearance > or = 90 mL/min) renal function. The area under the receiver operating characteristic curve for calculated creatinine clearance and serum creatinine concentration was 0.71 and 0.62, respectively, yielding a difference of 0.08 (P = .0004). No increased risk of mediastinitis or bleeding was observed in patients with renal insufficiency. CONCLUSION: Moderate and severe renal insufficiency independently increase the risk of early death after coronary artery bypass grafting. Our results indicate that calculated creatinine clearance is a better predictor of early mortality postoperatively than serum creatinine concentration.     

Prediction of residual total renal function before nephron-sparing surgery using99mTc-DMSA renal scintigraphy

Background Although radical nephrectomy is the standard treatment for renal cell carcinoma, nephron-sparing surgery is the preferred treatment in patients with a single functioning kidney. It is important before surgery to evaluate the level of residual renal function likely after the operation. In this study, we investigated the prediction of residual renal function, using technetium Tc 99m dimercaptosuccinic acid (^99mTc-DMSA) renal scintigraphy, before nephron-sparing surgery for renal tumors. Methods Preoperative and postoperative evaluation of renal function was done in 11 patients with renal cell carcinoma or renal angiomyolipoma, using^99mTc-DMSA scintigraphy. Nine patients had renal cell carcinoma and 2 had renal angiomyolipoma. Partial nephrectomy was performed in 4 patients and surgical enucleation in 7 patients. Both the predicted total DMSA renal uptake rate prior to surgery and the actual postoperative total^99mTc-DMSA renal uptake rate were obtained. Endogenous creatinine clearance and serum creatinine levels were also obtained. Results There was a good relationship between the predicted and postoperative total^99mTc-DMSA renal uptake rates. The ratio of the postoperative total DMSA renal uptake rate to the predicted total^99mTc-DMSA renal uptake rate was 85% after partial nephrectomy, and 101% after surgical enucleation. There was also a significant correlation between the postoperative total^99mTc-DMSA renal uptake rate and creatinine clearance, and postoperative total^99mTc-DMSA renal uptake rate levels above 11.4% coincided with serum creatinine levels below 2.0 mg/dL. Conclusion Preoperative assessment with^99mTc-DMSA renal scintigraphy is clinically useful for predicting residual renal function after nephron-sparing surgery.     

Image-guided biopsy-diagnosed renal cell carcinoma: critical appraisal of technique and long-term follow-up

OBJECTIVES: To critically appraise and determine the impact of image-guided biopsy on the management of indeterminate renal masses. A comparison of long-term follow-up of renal cell carcinoma (RCC) diagnosed by image-guided biopsy and radiologically obvious RCC was also carried out. PATIENTS AND METHODS: Data were collected for all the consecutive patients requiring renal core biopsies for the diagnosis of indeterminate renal masses between January 1996 and January 2006. The long-term outcome of diagnostic and nondiagnostic renal biopsies was assessed. Furthermore, the long-term outcome of RCC diagnosed following biopsies was compared with nonbiopsy radical nephrectomy done during the same time period. RESULTS: Of the 70 biopsy procedures performed, 9 were nondiagnostic and 61 were diagnostic on histopathologic examinations (17 benign and 44 malignant). The histopathology of all radical nephrectomies was identical to the pathology of biopsy specimens. Of the nine nondiagnostic cases, one patient had a repeat biopsy that was confirmed as RCC. Six patients including the case diagnosed to have RCC on repeat biopsy underwent radical nephrectomy in the nondiagnostic group. The histopathology revealed RCC in four, and angiomyelolipoma and pyelonephritis in one each. The remaining three nondiagnostic cases are under follow-up; there has been no change in the size of the lesions in a mean follow-up of 32 mo (range: 12-52). There has been no change in the size of benign lesions at a mean follow-up of 29 mo (range: 3-72). The procedure-related complication in the form of bleeding following biopsy was observed in one patient, which settled conservatively. There was no statistically significant difference (chi-square=1.134 and p value equal to 0.379) in the recurrence rate and metastases between the biopsy radical nephrectomy and nonbiopsy radical nephrectomy groups for the same stage of disease during the same period. CONCLUSIONS: Image-guided biopsy is safe and accurately characterises indeterminate renal masses. A repeat biopsy protocol is useful in case of a nondiagnostic first biopsy. The long-term outcome following radical nephrectomy of biopsy-diagnosed RCC does not differ from the radiologically obvious RCC.     

Comparison of 1,800 laparoscopic and open partial nephrectomies for single renal tumors

PURPOSE: Laparoscopic partial nephrectomy is an increasingly performed, minimally invasive alternative to open partial nephrectomy. We compared early postoperative outcomes in 1,800 patients undergoing open partial nephrectomy by experienced surgeons with the initial experience with laparoscopic partial nephrectomy in patients with a single renal tumor 7 cm or less. MATERIALS AND METHODS: Data on 1,800 consecutive open or laparoscopic partial nephrectomies were collected prospectively or retrospectively in tumor registries at 3 large referral centers. Demographic, intraoperative, postoperative and followup data were compared between the 2 groups. RESULTS: Compared to the laparoscopic partial nephrectomy group of 771 patients the 1,028 undergoing open partial nephrectomy were a higher risk group with a greater percent presenting symptomatically with decreased performance status, impaired renal function and tumor in a solitary functioning kidney (p<0.0001). More tumors in the open partial nephrectomy group were more than 4 cm and centrally located and more proved to be malignant (p<0.0001 and 0.0003, respectively). Based on multivariate analysis laparoscopic partial nephrectomy was associated with shorter operative time (p<0.0001), decreased operative blood loss (p<0.0001) and shorter hospital stay (p<0.0001). The chance of intraoperative complications was comparable in the 2 groups. However, laparoscopic partial nephrectomy was associated with longer ischemia time (p<0.0001), more postoperative complications, particularly urological (p<0.0001), and an increased number of subsequent procedures (p<0.0001). Renal functional outcomes were similar 3 months after laparoscopic and open partial nephrectomy with 97.9% and 99.6% of renal units retaining function, respectively. Three-year cancer specific survival for patients with a single cT1N0M0 renal cell carcinoma was 99.3% and 99.2% after laparoscopic and open partial nephrectomy, respectively. CONCLUSIONS: Early experience with laparoscopic partial nephrectomy is promising. Laparoscopic partial nephrectomy offered the advantages of less operative time, decreased operative blood loss and a shorter hospital stay. When applied to patients with a single renal tumor 7 cm or less, laparoscopic partial nephrectomy was associated with additional postoperative morbidity compared to open partial nephrectomy. However, equivalent functional and early oncological outcomes were achieved.     

The impact of cystinuria on renal function

PURPOSE: Patients with cystinuria frequently have recurrent renal calculi and may subsequently require multiple stone removing procedures during their lifetime which could have an impact on overall renal function. We determined the potential impact of cystinuria and cystine stone formation on the level of renal function compared to calcium oxalate stone formers. MATERIALS AND METHODS: Clinical data on 40 cystinuric patients followed at 2 medical centers and 45 such individuals in a large stone population data base were analyzed. These results were compared to data on 3,964 calcium oxalate stone formers enrolled in this data base. RESULTS: Mean serum creatinine plus or minus standard deviation for stone forming cystinuric patients was significantly higher than that of the calcium oxalate cohort (1.13 +/- 0.28 versus 1.01 +/- 0.28 mg./100 ml., p = 0.0001). A significantly greater percentage of cystinuric patients (5.8%) had an abnormally increased serum creatinine compared to the calcium oxalate stone formers (2.2%, p = 0.046). Male gender, increasing number of open surgical stone removing procedures and nephrectomy were significant variables associated with an increased serum creatinine (p = 0.0010, p = 0.0038, p = 0.0133, respectively). An increasing number of open surgical stone removing procedures had a significant positive correlation with performance of nephrectomy in the cystinuric population (p = 0.0166). A significantly greater percentage of cystinuric patients compared to the calcium oxalate cohort were subjected to nephrectomy (14.1% versus 2.9%, p = 0.007). CONCLUSIONS: Cystinuric patients have higher serum creatinine levels than calcium oxalate stone formers and they are at more risk for renal loss. When stone removal is required, a minimally invasive approach is preferred.     

Predictive factors for the development of chronic renal insufficiency after renal surgery: a multicenter study

Purpose

To evaluate which factors affecting changes in postoperative renal function after conducting radical nephrectomy or partial nephrectomy.

Methods

Data on patients who underwent operations for renal cell carcinoma between 2000 and 2010 at multiple institutions were collected. Patient characteristics including preoperative estimated glomerular filtration rate (EGFR) were investigated, and types of surgery and postoperative results were evaluated. Renal insufficiency was defined as an EGFR <60 ml/min/1.73 m². Cox proportional hazard regression analysis was used to investigate which factors were associated with chronic renal insufficiency after surgery.

Results

A total of 2,454 patients were included for evaluation; 1,502 patients underwent radical nephrectomy, whereas 952 patients underwent partial nephrectomy. The mean follow-up period was 44.48 ± 27.04 months (range, 12–120 months). Factors affecting EGFR were age, diabetes, hypertension, surgical procedure, and preoperative creatinine level (p < 0.001). Factors affecting postoperative renal insufficiency were age, surgical procedure, serum creatinine level, and EGFR.

Conclusion

The risk for developing post-nephrectomy renal insufficiency in patients who underwent radical nephrectomy was higher than those who underwent partial nephrectomy. Factors affecting post-nephrectomy renal insufficiency were age, preoperative serum creatinine level, and preoperative EGFR. In addition to radical nephrectomy, patient >58 years with a preoperative serum creatinine >1.03 mg/ml, and EGFR <73 ml/min/1.73 m² had a higher probability of developing post-nephrectomy chronic renal insufficiency.