Application of super—selective renal artery embkolization in renal injuries

Objective:To use super-selective renal artery embolization in treatment of patients with renal injuries.Methods:From 1991 to 1998,11 cases of renal injuries due to different causes underwent super-selective renal artery embolization.In these patients,91% of injury sites were segmental arteries and their branches.All the patients were treated with steel coil for embolization.Results:Nine patients showed prompt cessation of hematuria,and in 2 patients hematuria stopped 2-4 days after embolization.Conclusions:Super-selective renal artery embolization (SSRAE) is suitable for severe hematuria,limited size of kidney injuries,stable hemodynamic parameters after conservative treatment and low reserve of renal function.Steel coil is an effective embolic material,Rapid hemostasis can be fulfilled and renal function can be reserved.super-selective renal artery embolization has low incidence of comkplications and can shorten hospitalization time.     

Under-grading of <4 cm renal masses on renal biopsy

Study Type – Prognosis (case series) Level of Evidence 4 What's known on the subject? and What does the study add? It is well documented that biopsy of small renal masses is inaccurate and tends to under‐estimate tumour grade compared with surgical specimens. To our knowledge there has not been a study showing grading discrepancy between biopsy and surgical excision in a large population‐based cohort.

OBJECTIVE

• ? To determine whether differences exist in tumour grade between patients who undergo partial nephrectomy (PN) and those who undergo ablation for renal tumours.

PATIENTS AND METHODS

• ? Data was obtained using the Surveillance, Epidemiology and End Results database. Patients with solitary renal tumours of <4 cm treated with ablation or PN and with renal cell carcinoma (RCC) histopathology were identified.
• ? Tissue diagnosis in the ablation specimens was obtained from biopsy reports, whereas tissue from PN specimens was determined from surgical pathology.
• ? Variables analysed included: year of diagnosis, age, sex, race/ethnicity, marital status, population density, education, poverty level, and tumour size.
• ? Stacked bar graphs were created to compare the distributions of grade and histology between the groups. Multinomial logistic regression was used to determine factors independently associated with grade.

RESULTS

• ? In all, 7704 (87.4%) patients underwent PN and 1114 (12.6%) underwent either radiofrequency ablation or cryoablation.
• ? The PN patients were younger at diagnosis (59 vs 68 years, P < 0.001), more likely to be married (70% vs 64%, P < 0.001), and had smaller tumours (2.4 vs 2.6 cm, P < 0.001).
• ? There were no differences in the distribution of histology between the PN and ablation groups.
• ? Tumour grade was significantly lower in tumours treated with ablation.
• ? Compared with grade 1 disease, those undergoing ablation were 30% less likely to have grade 2 (P < 0.001), 30% less likely to have grade 3 (P < 0.001), and 92% less likely to have grade 4 disease (P < 0.01) than those having PN.

CONCLUSIONS

• ? There is a strong association between grade and treatment type in patients with small renal masses after controlling for baseline characteristics.
• ? As grade is determined by different methods, we think that this shows systematic under‐grading in biopsy of small renal masses.

     

Sex and the pregnant kidney: does renal allograft gender influence gestational renal adaptation in renal transplant recipients?

BACKGROUND: Animal work indicates that ovarian hormones are important in initiating and maintaining enhanced renal function in pregnant rats and that a renal response resembling pregnancy can be provoked in male rats exposed to pregnancy hormones. Women becoming pregnant following renal transplantation provide an opportunity to compare the functional response of male and female allografts to the gestational endocrine environment. METHODS: This retrospective observational study included 20 renal allograft recipients (age 29.7 +/- 2.4 yrs) (mean +/- SE) who had 22 pregnancies beyond 24 weeks (gestation at delivery 35.5 +/- 0.6 weeks). Donor characteristics, transplant details, renal follow-up data, and information about pregnancy and allograft function were obtained from hospital notes. RESULTS: Thirteen women received male allografts (donor age 30.0 +/- 3.9 years) (mean +/- SEM) and 7 women, female allografts (donor age 45.1 +/- 6.0 years) (P = .04). There were no significant differences between the two groups in maternal recipient age, transplant to pregnancy interval, antenatal complications, pregnancy outcome, or postnatal graft function. Compared to prepregnancy values serum creatinine (SCr) decrements and augmented 24-hour creatinine clearance (CrCl) were observed over the first trimester in both male and female allografts: Delta CrCl from 106.8 +/- 13.2 mL/min to 114.4 +/- 11.4 mL/min (35.6% increase) and 71.8 +/- 7.4 to 89.5 +/- 11.3 mL/min (24.7% increase), respectively, and Delta SCr from 90.1 +/- 5.4 micromol/L to 73.6 +/- 6.6 micromol/L (17.8% decrease) and 99.8 +/- 9.7 micromol/L to 78.0 +/- 5.7 micromol/L (13.5% decrease), respectively. Differences between the two groups did not reach statistical significance. CONCLUSIONS: Donor gender and/or age do not appear to influence the gestational renal response in kidney transplant recipients.     

Oliguria: A sign of renal success or impending renal failure?

Limiting renal impairment begins with identifying patients at increased risk for renal dysfunction (monitoring of renal function is important in these patients) and understanding the physiology of urine formation, the influence of anesthetic drugs, and intraoperative events on the physiology and pathophysiology of renal function. The fundamental principles emphasized in this article include avoidance of hypovolemia or renal hypoperfusion (e.g., hypotension, decreased cardiac output) in patients at risk (because of pre-existing disease or the nature of the operative procedure) and limitation of toxins that might jeopardize residual renal function. Direct monitors of renal well-being are still in the rudimentary stage of development. Indirect measures of renal function (CVP, MAP) are used on a minute-to-minute basis. The clinical measurement of urine output still is relied on when evaluating renal function over longer time intervals. Currently, only one drug (N-acetylcysteine) improves renal outcome after a high-risk procedure (radiocontrast administration) prophylactically. Manipulation of autorenal regulatory vasodilators (e.g., nitric oxide, PGE2) and vasoconstrictors (e.g., endothelin, vasopressin, angiotensin II) may prove helpful in the future. Currently, maintenance of adequate intravascular volume, MAP, and cardiac output are the most important renal protective measures an anesthesiologist can provide to preserve renal function high-risk patients.     

Acute renal failure due to bilateral matrix renal calculi – A diagnostic dilemma

We report an unusual case of acute renal failure caused by bilateral matrix calculi. The difficulties in diagnosing the cause of renal failure and the management of the case are discussed. Matrix calculi are rare causes of acute renal failure. Being radiolucent they can be elusive and systematic investigation and a diligent search are required for correct diagnosis and appropriate treatment.     

Can cerebral vasoreactivity predict cerebral tolerance to carotid clamping during carotid endarterectomy?

Cerebral vasoreactivity (CVR) was evaluated as a preoperative test in predicting cerebral tolerance to carotid clamping.A consecutive series of 115 carotid endarterectomy (CEA) cases were studied. Before surgical operation CVR was evaluated, by measuring the mean velocity of the middle cerebral artery (mv-MCA) using transcranial Doppler (TCD) at the basal condition and 20 min after intravenous administration of acetazolamide (1 g). CEA was performed under general anesthesia. TCD was used during surgery to evaluate mv-MCA and to calculate mv-MCA clamping/mv-MCA pre-clamping x100 ratio (mv-MCA%), which was used as the parameter to validate CVR.CVR did not correlate with mv-MCA% (r=0.22). There was no significant difference (P=0.09) between mean values of the non shunted subgroup and the shunted one.CVR does not seem to be suitable for evaluating cerebral tolerance to carotid clamping.     

Stenting of renal artery stenosis: is it beneficial in chronic renal failure?

BACKGROUND: The utility of renal artery stenting (RS) in preserving renal function (RF) is not well established. Our prospective study aimed to examine the clinical effects of RS in patients with proximal renal artery stenosis and chronic renal failure (CRF). METHODS: Fifty-two patients, with atherosclerotic renal artery stenosis (ARAS) and renal impairment underwent successful monolateral (33 patients) or global RS (19 patients: six bilateral stenting, two surgical solitary kidney and 11 functional solitary kidney). Patients were considered eligible if they had at least a mild renal impairment (serum creatinine (Cr) >1.5 mg/dL). To assess a significant change in RF, we compared the slopes of the regression lines derived from the reciprocal of Cr vs. time, plotted before and after stenting. Patients had a median post-procedure follow-up of 24 months (range 9-54). RESULTS: Before stenting all patients exhibited a negative slope, indicating progressive renal failure. After stenting the slopes became positive in eight patients (15.5%), indicating a significant improvement in RF; in 31 patients (59.5%) the slopes were not significantly different from 0 and were associated with a stable RF, while 13 patients (25%) presented negative slopes and showed a continuous reduction in RF. Previous serum Cr, initial diameter of the treated kidney, vascular resistive index, and mono vs. global stenting were not significantly associated to post stenting RF. CONCLUSIONS: RS appears to be associated with RF stabilization in the majority of patients with CRF.     

The management of renal artery atherosclerosis for renal salvage: does stenting help?

OBJECTIVE: The use of endovascular techniques to treat renal artery stenosis (RAS) has increased in recent years but remains controversial. The purpose of this study was to review the outcomes and durability of percutaneous transluminal angioplasty and stenting (PTA/S) for patients with RAS and decreasing renal function. METHODS: Between 1999 and 2004, 125 consecutive patients underwent angiography and intervention for renal salvage and formed the basis of this study. Inclusion criteria for this study included serum creatinine greater than 1.5 mg/dL, ischemic nephropathy, and high-grade RAS perfusing a single functioning kidney. Patients undergoing PTA/S for renovascular hypertension or fibromuscular dysplasia or in conjunction with endovascular stent grafting for aneurysm repair were excluded. The original angiographic imaging was evaluated for lesion grade and parenchymal kidney size. All medical records and noninvasive testing were reviewed. Preoperative and postoperative patient data were standardized and analyzed by using chi(2) tests for nominal values and t tests for continuous variables. The Modification of Diet in Renal Disease equation was used to estimate glomerular filtration rate (GFR), and univariate analysis was performed. RESULTS: Preoperative variables included the presence of coronary artery disease (93%), diabetes (44%), tobacco use (48%), and hypercholesterolemia (70%). RAS was suspected on the basis of preoperative duplex imaging or magnetic resonance angiography. Aortography and PTA/S were performed in 125 patients (mean age, 71 years; 59% male) with a mean baseline creatinine level of 2.2 mg/dL. There were two mortalities (1.6%) in the 30-day postoperative period, but there was no case of acute renal loss. Blood pressure decreased after PTA/S (151/79 mm Hg before vs 139/72 mm Hg after 1 month; P < .03). For all patients, the estimated GFR went from 33 +/- 12 mL . min(-1) . 1.73 m(-2) (mean +/- SD) to 37 +/- 19 mL . min(-1) . 1.73 m(-2) at 6 months (P = .10). Sixty-seven percent of treated patients had improvement (>10% increase in GFR) or stabilization of renal function. A rapid decline in GFR before intervention was correlated with improvement after PTA/S. Responders after PTA/S had a 27% decrease in GFR before intervention (44 +/- 13 mL . min(-1) . 1.73 m(-2) to 32 +/- 13 mL . min(-1) . 1.73 m(-2); P < .001) with a negative to positive slope change in GFR values. Ten patients underwent reintervention for in-stent restenosis. Cases without improvement in GFR after PTA/S were associated with eventual dialysis need (P = .01; mean follow-up, 19 months). Survival at 3 years was 76%, and dialysis-free survival was 63% as estimated by Kaplan-Meier analyses. CONCLUSIONS: Renal artery stenoses causing renal dysfunction can be safely treated via endovascular means. Rapidly decreasing renal function is associated with the response to renal artery angioplasty/stenting and helps identify patients for renal salvage.     

Does cadaveric donor renal transplantation ever provide better outcomes than live-donor renal transplantation?

BACKGROUND: Live donor renal transplantation (LRT) now comprises more than 40% of all kidney transplants performed in the United States. Many patients on the cadaveric waiting list have a prospective live kidney donor. This study determines whether cadaveric donor renal transplantation (CRT) can demonstrate better outcomes than LRT. METHODS: From the United States Renal Data System registry, 31,909 adult recipients of a first-time kidney transplant from 1995 to 1998 were analyzed. Recipients were followed until December 31, 2000. RESULTS: CRT, more human leukocyte antigen (HLA) mismatches, increased donor age, cold ischemia time greater than 24 hr, African American recipient, and a history of diabetic nephropathy all increased the risk of graft failure, return to dialysis, and death. Nevertheless, in specific circumstances, CRT could provide better outcomes than LRT. For example, in recipients aged 18 to 59 years with a hypothetical live kidney donor aged 50 years and four HLA mismatches, the relative risk of graft loss with LRT is comparable or increased compared with CRT if the cadaveric kidney donor is much younger or with fewer HLA mismatches. On the other hand, for recipients aged 60 years or older, CRT never provides better outcomes than LRT. All analyses were adjusted for recipient race, gender, and history of diabetic nephropathy. There were no significant interactions among donor type, HLA mismatches, donor age, and cold ischemia time. CONCLUSIONS: The elderly recipient with an imminent LRT should never be offered CRT. A combination of recipient and donor factors can make CRT preferable to LRT in younger patients.     

Does division of the left renal vein during aortic surgery adversely affect renal function?

Between July 1980 and July 1988, 478 consecutive patients underwent aortic aneurysm operations at Royal Prince Alfred Hospital. Renal function was assessed by measurement of serum creatinine levels. The left renal vein was divided in 28 (8%) of the 355 patients undergoing elective aneurysm resection. The mean immediate postoperative creatinine values were significantly higher after left renal vein division, 193±174 mol/L, compared to 133±93 mol/l for those whose left renal vein remained intact (p < 0.05 by Mann-Whitney U test). After one month, serum creatinine levels had decreased but were still significantly higher in those patients in whom the left renal vein had been divided, 170±166 mol/l, compared to those in whom it was left intact 109±49 mol/l (p<0.05 by Mann-Whitney U test). The suprarenal aorta was cross-clamped in seven (25%) of the 28 patients in whom the left renal vein was divided, compared to 21 (6%) of the 327 with the left renal vein intact. A rise in creatinine level was observed after suprarenal aortic cross-clamping. The left renal vein was divided in 17 (14%) of the 123 patients having emergency surgery for ruptured aortic aneurysm, 61 (49%) of whom survived more than 30 days. The mean immediate postoperative creatinine values were significantly higher after left renal vein division, 426±277 mol/l, compared to those in whom the vein was left intact, 178±136 mol/l (p < 0.05 by Mann-Whitney U test). After one month, serum creatinine levels were still significantly higher in those patients in whom the left renal vein had been divided. Although division of the left renal vein is a useful way to improve exposure of the juxtarenal aorta, the maneuver is associated with an adverse effect on renal function.Presented at the Annual Meeting of the Peripheral Vascular Surgical Society, New York, New York, June, 1989.     

Pathophysiological changes in chronic renal insufficiency

The kidney has 3 major types of functional activity in normal humans：     

Expression of transforming growth factor β in renal cell carcinoma and matched non-involved renal tissue

TGF1 is one of several cytokines produced by proximal tubular and renal cancer cells. Previous studies have been mainly focused on determining plasma or serum TGF levels, its effect on RCC cultures, and the expression of TGF mRNA. Cancerous and autologous normal kidney samples were obtained from 24 patients treated by radical nephrectomy. TGF1 expression was determined using a semi quantitative Western blot analysis and immunohistochemistry. Blot densities and immunohistochemical expression intensities in normal and neoplastic tissue were compared, and subsequently correlated to tumor stage, histological type and nuclear grade. All tissue samples examined expressed TGF1; mean tumor to non-involved kidney spot density ratio correlated with advancing stage and higher nuclear grade. The overexpression of TGF1 in certain RCCs may partially explain their resistance to the growth suppression action of TGF. The correlation with tumor stage and grade indicates a possible role in the development of metastatic potential as well as in hosts immune response modulation.