Continuous renal replacement therapy improves renal recovery from acute renal failure

BACKGROUND: Acute renal failure (ARF) occurs in up to 10% of critically ill patients, with significant associated morbidity and mortality. The optimal mode of renal replacement therapy (RRT) remains controversial. This retrospective study compared continuous renal replacement therapy (CRRT) and intermittent hemodialysis (IHD) for RRT in terms of intensive care unit (ICU) and hospital mortality, and renal recovery. METHODS: We reviewed the records of all patients undergoing RRT for the treatment of ARF over a 12-month period. Patients were compared according to mode of RRT, demographics, physiologic characteristics, and outcomes of ICU and hospital mortality and renal recovery using the Chi square, Student's t test, and multiple logistic regression as appropriate. RESULTS: 116 patients with renal insufficiency underwent RRT during the study period. Of these, 93 had ARF. The severity of illness of CRRT patients was similar to that of IHD patients using APACHE II (25.1 vs 23.5, P = 0.37), but they required significantly more intensive nursing (therapeutic intervention scale 47.8 vs 37.6, P = 0.0001). Mortality was associated with lower pH at presentation (P = 0.003) and increasing age (P = 0.03). Renal recovery was significantly more frequent among patients initially treated with CRRT (21/24 vs 5/14, P = 0.0003). Further investigation to define optimal timing, dose, and duration of RRT may be beneficial. CONCLUSIONS: Although further study is needed, this study suggests that renal recovery may be better after CRRT than IHD for ARF. Mortality was not affected significantly by RRT mode.     

Influences of renal stone surgeries on renal function--evaluation of renal function with 99mTc-DMSA renal scintigraphy]

From 1984 to 1990, 99mTc-DMSA renal scintigraphy was performed before and after nephrolithotomy (15 cases), pyelolithotomy (15 cases), percutaneous nephrolithotripsy (PNL: 15 cases) and extracorporeal shock wave lithotripsy (ESWL: 16 cases, 17 kidneys) in order to evaluate of influences of renal stone surgeries on split renal function. DMSA renal uptake change ratio of treated kidneys of nephrolithotomy (-24.94 +/- 5.60%) was significantly lower than that of PNL (-0.06 +/- 3.92%), pyelolithotomy (-4.08 +/- 4.79%) (p less than 0.01) and ESWL (-7.72 +/- 3.87%) (p less than 0.05). The average change ratios of contralateral kidneys were as follows: PNL 4.80 +/- 4.21% nephrolithotomy 4.67 +/- 4.73%, pyelolithotomy -1.46 +/- 5.39% and ESWL -2.02 +/- 4.44%. One to 3 weeks after PNL, the cold area on the renal image was found in 10 (66.7%) of 15 cases. In cases of ESWL, DMSA renal uptake decreased even 4-10 weeks (mean 7 weeks) after treatment. In conclusion, possivility of deterioration of renal function after ESWL was suggested.     

Reversible renal hypertension due to renal hygroma

A hygroma of the left kidney was found at surgery in a thirty-five-year-old woman, who presented with anemia, hypertension, and a left abdominal mass. There was a very high sedimentation rate and fine needle aspiration yielded bizarre cells which raised the possibility of malignancy. Compression of the kidney by the cystic structure probably interfered with renal blood flow and was responsible for the elevated blood pressure which receded to normal after removal of the cyst and the left kidney.     

Extensive renal involvement by renal cell carcinoma

Experience with the management of 3 cases of bilateral renal adenocarcinoma and 1 case of unilateral carcinoma in the solitary kidney is presented. Two patients died of metastases six and thirteen months postoperatively, while one is alive with metastases at fourteen months and another is alive without metastases at four months. The literature is reviewed, and the various treatments are discussed.     

Transplantation of renal primordia: renal organogenesis

Dialysis and allotransplantation of human kidneys represent effective therapies to replace kidney function, but the former replaces only a small component of renal function, and the latter is limited by lack of organ availability. Xenotransplantation of whole kidneys from nonprimate donors is complicated by humoral and severe cellular rejection. The use of individual cells or groups of cells to repair damaged tissue (cellular therapies) offers an alternative for renal tissue replacement. However, recapitulation of complex functions such glomerular filtration and reabsorption and secretion of solutes that are dependent on a three-dimensionally integrated kidney structure are beyond the scope of most cellular replacement therapies. The use of nonvascularized embryonic renal primordia for transplantation circumvents humoral rejection of xenogeneic tissue and ameliorates cellular rejection. Renal primordia are preprogrammed to attract a vasculature and differentiate into a kidney and in this manner undergo organogenesis after transplantation into the mesentery of hosts. Here we review a decade’s progress in renal organogenesis.     

Improved renal function after renal artery revascularization

An experience with 20 patients with renovascular hypertension and renal insufficiency secondary to renal artery stenosis is presented. The mean follow-up was 29 months. Eighteen patients had atherosclerotic renal artery stenosis and two patients had transplant renal artery stenosis. The mean preoperative blood pressure of 162 +/- 5 mmHg decreased significantly to 105 +/- 2 mm Hg (p less than 0.001). The serum creatinine also decreased from a mean preoperative level of 4.7 +/- 0.7 mg/dl to a mean postoperative level of 2.3 +/- 0.3 mg/dl (p less than 0.001). Similarly, the creatinine clearance improved from a mean preoperative level of 28 +/- 2 ml /min to a mean postoperative level of 45 +/- 8 ml/min (p less than 0.03). Four patients (20%) with improved renal function died from 4 days to 15 months postoperatively. Two patients (10%) have progressed to end stage renal disease. These findings demonstrate that renal revascularization is clearly beneficial in the short-term and long-term improvement of renal function.     

Patients with renal hypouricemia with exercise-induced acute renal failure and chronic renal dysfunction

We here report the case of a 38-year-old male with back pain and vomiting occurring after exercise. Serum creatinine level was elevated, and he was admitted to our hospital with diagnosis of acute renal failure (ARF). He had experienced similar attacks at least 4 times, including the present episode, from the age of 22 years. After admission, the patient was managed only by resting, and remission was nearly attained in about 1 month. The renal biopsy specimen performed on day 15 showed findings of acute tubular necrosis, thickening of the tubular basement membrane, and interstitial fibrosis. After remission, the serum uric acid level was 0.7-0.8 mg/dl, fractional excretion of uric acid was 0.63, and the possibility of other diseases facilitating the excretion of uric acid was denied. Therefore, ARF associated with idiopathic renal hypouricemia was diagnosed. Since only mild responses were observed in a pyradinamide loading test and a benzbromarone loading test, the case was considered to be a presecretary reabsorption disorder type. Renal function tests showed the almost complete recovery of the glomerular filtration rate (GFR: 114 ml/min/1.73 m2), but the urine concentrating ability was markedly decreased (specific gravity 1.019 and osmolarity 516 mOsm/kgxH2O in Fishberg test). Past data from this patient indicated that this renal dysfunction had been persisting for ten years. We examined 9 patients with renal hypouricemia and focused on the differences between the two groups (with or without complications). Four patients had a history of exercise-induced ARF or calculus. The urine concentrating ability was significantly lower in these patients (group A) than in the other patients without complications (group B). The glomerular filtration rate in group A was within the normal range, but was lower than in group B. These results suggested the possibility that patients with renal hypouricemia with complications may have chronic renal dysfunction in the future.     

The renal medulla in acute renal allograft rejection: comparison with renal cortex

A retrospective cohort study was undertaken to evaluate thediagnostic value of the renal medulla in acute renal allograftrejection (ARAR). One hundred and ninety-five biopsies from98 patients were randomly selected out of 565 transplant biopsies.Biopsies were graded blindly from Grade 0 (no rejection) toGrade 3 (severe rejection) using standard criteria; ARAR wasconfirmed by a fall in all cases of mean serum creatinine concentrationfrom 0.331 ± 0.182 to 0.184 ± 0.079 mmol/l, withanti-rejection therapy. In the 43 biopsies which contained bothcortex and medulla, the ARAR grades and the intensities of mononuclearcell, plasma cell, polymorphonuclear cell and eosinophil infiltrates,and of interstitial oedema and haemorrhage, were similar incortex and medulla (Spearman's Rank Correlation r=0.55–0.81,P < 0.001 ). The sensitivity, specificity and overall accuracyof medullary changes in predicting ARAR changes in the cortexwere 77%, 100% and 38%, respectively. Acute vascular rejectionchanges could not be compared between renal cortex and renalmedulla because of the anatomical differences between cortexand medulla. Further evaluation of ARAR in the all 195 biopsies,of which 188 had cortical tissue and 50 had medullary tissue,showed no significant differences in histological features (P> 0.05), except for more cortical biopsies with plasma cells(29%) than medullary biopsies with plasma cells (10%; P <0.02). It is concluded that: (1) ARAR histological changes aresimilar in cortex and medulla; (2) the predictive value of ARARmedullary changes for cortical rejection changes has low sensitivity(77%) and high specificity (100%). It is suggested that a predominantlynormal medullary renal biopsy in suspected rejection shouldbe repeated to obtain cortical tissue.     

Polycystic renal disease and bilateral renal cancer

The authors report a case of polycystic kidneys complicated by bilateral renal hypernephroma. This association has been rarely described and is probably frequently unrecognized because of the diagnostic difficulties. Angiography should be performed in all doubtful cases in order to obtain an early diagnosis so that the patients can benefit from modern therapeutic techniques. Polycystic kidneys is a familial hereditary disease capable, like other genetic diseases, of malignant transformation. Clinically undiagnosed partial forms of the disease can be the origin of certain cases of apparently primary renal cancer.     

Abnormal renal arteriography after renal trauma.

Angiograms following renal trauma in a ten-year-old girl were highly suggestive of renal neoplasm, especially Wilms' tumor. There are striking similarities between arteriograms after renal trauma and those showing neovascularity.     

Corner-saving renal artery anastomosis for renal transplantation

Renal transplantation is the preferred treatment for most patients with end-stage renal disease. Postoperative vascular complications that significantly affect graft loss include stenosis and renal artery thrombosis. Our transplant team has performed 1635 procedures since 1975. Since December 2003, we have performed a corner-saving technique for the renal artery anastomoses in 183 recipients. In this study, we retrospectively analyzed the outcome data from these procedures in 43 women and 140 men of overall mean age of 31.6 years (range, 7-66 years). Graft tissue was obtained from deceased donors in 47 and from living donors in 136 recipients. The mean age of the donors was 39.8 years (range, 6-67 years). The graft renal arteries were spatulated from the posterior walls of the renal artery to provide wide anastomoses. Using this technique, a renal artery stenosis occurred at 5 months after renal transplantation in 1 recipient (0.54%). It was treated successfully with balloon angioplasty and placement of an intraluminal stent. We did not encounter any instances of renal artery thrombosis during a mean follow-up of 20.6 +/- 11.6 months (range, 1-40 months). During follow-up, 5 recipients died, and 9 returned to hemodialysis. At the time of this writing, the remaining 169 recipients (92.3%) are alive with good graft function. In conclusion, owing to its low complication rate, we believe our new corner-saving technique to be the safest way to perform a renal artery anastomosis.     

Multifocal renal cell carcinoma on renal allograft

Development of neoplasms after a renal transplantation is well known, but allograft neoplasms are uncommon. Diagnostics studies include routine ultrasonography, and CT. In some selective cases, if the graft is functionally salvageable and it is technically feasible, a nephron-sparing surgery should be performed. In any case, standard intervention is nephrectomy. We report a case of multifocal renal cell carcinoma diagnosed in a kidney grafted 17 years before.     

Reduction in renal function after renal arteriography and after renal artery angioplasty.

OBJECTIVE: To investigate the incidence and risk factors for renal function deterioration after renal angiography and angioplasty or stenting. METHODS: A retrospective study of 85 consecutive patients undergoing selective renal artery arteriography (n = 53) or renal artery angioplasty % (PTRA) stenting (n = 32) for renal artery stenosis. Multivariate logistic regression analysis was used to determine independent predictors of deterioration of renal function, defined as an increase of serum creatinine by at least one third within 24 h. RESULTS: Deterioration of renal function occurred in 13 patients (15%), [8/53 (15%) after angiography and 5/32 (16%) after PTRA/stenting]. Only pre-existing renal impairment (se-creatinine > or = 177 mumol/l) (Odds ratio: 40; 95% confidence interval 1.2-72, p = 0.02) and administered dosage of contrast agent (more than 225 ml) (OR 67; 95% CI 11.8-100, p = 0.02) were independently associated with renal function deterioration. CONCLUSION: Transient renal dysfunction after renal artery angiography or PTRA/stenting occurs in about 15% of patients, but persistent renal failure is uncommon. Pre-existing renal impairment and amount of contrast agent are independent risk factors. Endovascular treatment of renal artery stenosis is not associated with a higher risk of renal deterioration compared to selective renal angiography.     

Relation between renal calcium content and renal impairment in 246 human renal biopsies

Tissue calcium content from 246 diagnostic human renal biopsies was measured to assess whether elevated tissue calcium concentration could be demonstrated to exist early during the course of human renal disease or was only a manifestation of advanced renal impairment. Renal calcium content correlated significantly with serum creatinine (r = +0.23, P less than 0.001, N = 246); serum phosphate P less than 0.001, N = 169) but not with serum calcium (r = -0.10, P greater than 0.1, N = 193). Fivefold greater calcium content was measured in biopsied patients with normal renal function than in normal postmortem renal tissue (35.7 +/- 5.2 vs. 7.6 +/- 0.7 mgCa/100 g wet renal tissue, P less than 0.001). Those biopsied patients with significant functional impairment (SCr greater than 1.5 mg/dl) had a higher mean level of serum phosphorus and serum [Ca] X [P] product than patients with normal renal function (5.19 +/- 0.22 vs. 3.92 +/- 0.11 mg P/dl and 44.8 +/- 1.8 vs. 35.7 +/- 1.2 mg2/dl2, respectively), and slightly higher renal calcium content (85.3 +/- 32.2 vs. 35.7 +/- 5.2 Ca/100 g wet renal tissue, P = 0.06), which correlated with histologic calcium deposition (r = +0.52, P less than 0.02, N = 20). These findings are consistent with the hypothesis that renal calcium deposition begins early in the course of a variety of renal diseases and hence may play a secondary pathogenetic role that accelerates progression to chronic renal failure. Severity of renal calcium deposition is equally closely related to hyperphosphatemia and to the level of renal impairment.