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W C Nahas

Publications and source records attributed to W C Nahas.

At least 19 recordsLinked to original sources
PubMed2001

Catheter-associated urinary infection in kidney post-transplant patients.

CONTEXT: There is still controversy as to the use and dosage of antimicrobial prophylaxis of the urinary infection associated with urethral catheterization in the post renal transplant period. OBJECTIVE: To determine whether patients develop urinary infection during short-term urethral catheterization after renal transplant without routine antimicrobial prophylaxis. DESIGN: Prospective study. SETTING: Kidney Transplantation Unit. SAMPLE: 20 patients submitted to non-complicated kidney transplant, with a normal urinary tract and no risk factors present regarding urinary infection. Aged 15 to 65 years. MAIN MEASUREMENTS: Before the transplant, material from the urethral meatus and urine were collected for culture. After the transplant, in the period during which the patient was with short-term urethral catheterization (4 to 5 days), material from the urethral meatus and urine from the bladder and the collecting bag were taken daily from all recipients for culture. RESULTS: There was a predominance of coagulase-negative Staphylococcus and S. viridans in the normal urethral meatus flora and in the first two days of urethral catheterization. After the second day, there was a predominance of E. coli and E. faecalis. Urinary infection did not occur during the period of urethral catheterization. In the follow up only one female patient (7%) had asymptomatic bacteriuria caused by E.coli after the withdrawal of the urethral catheter. CONCLUSIONS: Infection urinary does not occur during the period of urethral catheterization in kidney post-transplant patients. Thus, antimicrobial prophylaxis is not recommended for these patients to prevent urinary infection.

Adolescent↗
PubMed2001

Comparison of palpation-guided and ultrasound-guided biopsies in transplanted kidneys.

UNLABELLED: Biopsy is the gold standard for the diagnosis of conditions affecting the function of renal allografts. Obtaining representative tissue in biopsies is critical but these procedures are associated with up to 9% of complications and 20% of inadequate material. Although ultrasound guidance allows perfect control of depth and location of the graft, there is controversy regarding the cost-benefit of its use and reports of unsuitable material in ultrasound-guided biopsies are still high. PURPOSE: To compare ultrasound with the palpation method to guide biopsies in order to see if there is any difference between both methods and which one is better. PATIENTS AND METHODS: The casuistic consisted of 82 renal transplant patients (32 female and 50 male patients, age ranging between 5 and 64 yr; m=31.2 yr) randomized into two groups: GI, palpation-guided; GII, ultrasound-guided. Fifty-six biopsies were performed in GI and 66 in GII. RESULTS: Number of glomeruli, arcuate, and interlobar arteries and arterioles were compared in the two groups and were 503 (m=10) vs. 801 (m=12.9), 24 (m=0.5) vs. 38 (m=0.6), 104 (m=2.1) vs. 154 (m=2.5), and 174 (m=3.5) vs. 264 (4.3), respectively (p<0.05). Inadequate material for analysis in GI and GII was 7.1 and 7.6%, respectively (p=0.72). CONCLUSIONS: Although ultrasound guidance improves the number of glomeruli, arcuate, and interlobar arteries, as well as arterioles, compared with palpation-guided biopsies, there is no difference in the rate of adequate material between the two methods.

Adolescent↗
PubMed2001

Introduction of mycophenolate mofetil and cyclosporin reduction in children with chronic transplant nephropathy.

Chronic transplant nephropathy (CTN) is the most important cause of kidney graft dysfunction. Studies in adult populations have reported a beneficial effect of non-nephrotoxic mycophenolate mofetil (MMF) on graft function in this setting. However, few studies were reported in children in this setting. We therefore reviewed the charts/medical records of renal transplanted patients < 18 yr of age at a single center who had switched from azathioprine to MMF as a result of progressive loss in graft function, for which vascular, infectious, and urological causes were excluded. Serum creatinine (SCr) and calculated creatinine clearance were compared prior to and after MMF introduction. Thirteen patients (nine male/four female), followed-up for 59.3 +/- 35.4 months after transplantation, were analyzed. Age at MMF introduction was 14.2 +/- 3.6 yr. In 11 patients a previous biopsy had shown features of CTN and four patients also presented signs of chronic cyclosporin A (CsA) nephrotoxicity. MMF was started at a dose of 1211 +/- 351 mg/day, and the CsA dose was decreased from 6.69 +/- 3.15 mg/kg/day 6 months before MMF to 4.8 +/- 2.3 mg/kg/day at the time of MMF introduction. CsA was withdrawn in four patients. The median (25-75%) SCr value increased from 1.60 mg/dL (range 1.3 to 1.87 mg/dL) 6 months before MMF to 2.2 mg/dL (range 1.87-2.32 mg/dL) when MMF was introduced. Six months after introduction of MMF, the SCr level had decreased to 1.5 mg/dL (range 1.2-1.8 mg/dL) and remained stable until the last follow-up (17.5 +/- 9.2 months after MMF was started). A similar pattern occured with calculated SCr clearance. There were no acute rejections after changes in immunosuppression. The safety of MMF was also analyzed and in only one patient was the drug stopped as a result of intractable diarrhea. These findings suggest that MMF is sufficiently powerful to allow a decrease/withdrawal of CsA without the burden of acute rejection in a pediatric population with CTN.

Creatinine↗
PubMed2001

Incisional hernia and its repair with polypropylene mesh in renal transplant recipients.

PURPOSE: We evaluate the incidence of incisional hernia after kidney transplantation, predisposing factors and the results of surgical repair with polypropylene mesh. MATERIALS AND METHODS: We reviewed the records of 371 consecutive kidney transplants performed between April 1995 and February 2000. Patients with clinical signs of hernia at the transplant incision site were included in the study. Predisposing factors for incisional hernia were also reviewed. A prospective protocol of surgical correction was established using polypropylene mesh and patient outcome was studied. RESULTS: We identified 14 patients (3.8%) with an incisional hernia at the transplant incision site. Hernias developed 3 to 840 days after transplant surgery and were significantly more common in white (p = 0.019) and cadaveric graft (p = 0.02) recipients. Predisposing factors in 11 cases included complications of transplant surgery in 7, bladder obstruction in 2, large polycystic kidneys in 1 and chronic pulmonary disease in 1. Surgical repair was performed by primary fascial approximation and polypropylene mesh reinforcement in 13 cases and by pre-peritoneal mesh placement in 1. Minor subcutaneous wound infection developed in 1 patient. No relapses were noted at a mean followup of 17.8 months. CONCLUSIONS: In the majority of cases incisional hernia develops in the first 3 months after transplant surgery. The incidence is significantly higher in white patients and after cadaveric donor transplantation. Surgical complications of transplant surgery are important predisposing factors for incisional hernia after kidney transplantation. Surgical repair using polypropylene mesh is safe and effective in this group of patients.

Adult↗
PubMed2000

Extraperitoneal access for kidney transplantation in children weighing 20 kg. or less.

PURPOSE: We present our experience with kidney transplantation in children weighing 20 kg. or less. Surgery was done via extraperitoneal access while preserving the peritoneal cavity intact with special attention given to technical feasibility and the complication rate. MATERIALS AND METHODS: Included in our study were 46 children with a median age of 7 years weighing 20 kg. or less (mean 16.6), of whom 16 weighed less than 15 kg. (median 13.2). The 25 boys and 21 girls underwent a total of 49 kidney transplants, including 2 in 3 during the study. Donors were living related in 44 cases and cadaveric in 5. Surgical access was obtained by making a J-shaped pararectal incision in a curvilinear fashion from the symphysis pubis to near the costal border. RESULTS: Mean hospital stay was 22.9 days (range 6 to 83) and mean followup was 55.8 months (range 12 to 131). All patients received water on day 1 and food on day 2 postoperatively. In 6 patients 7 surgical complications developed, including urinary fistula in 2, superficial wound infection in 2 and vascular complications in 3 (renal vein thrombosis, stenosis and renal artery kinking in 1 each). Only 1 graft was lost due to a surgical complication. CONCLUSIONS: There are many advantages to using extraperitoneal access without an increase in surgical complications or technical difficulty. Absent gastrointestinal complications, an easier way to perform percutaneous biopsy, treatment of any surgical complication with no need for repeat laparotomy and the possibility of using the peritoneal cavity when dialysis is needed postoperatively are attractive justifications for extraperitoneal access.

Body Weight↗
PubMed1999

The impact of azathioprine on chronic viral hepatitis in renal transplantation: a long-term, single-center, prospective study on azathioprine withdrawal.

BACKGROUND: In transplanted patients, viral hepatitis progresses to chronic liver disease and patient's death after many years of transplantation. Also, it is well known that azathioprine (AZA) is harmful to the liver of these patients. However, it is unclear whether a low dose of AZA still represents a threat to the viral liver disease. METHODS: A total of 79 patients with hepatitis C, B, or both, transplanted between 1973 and 1990, were grouped according to whether they had AZA either withdrawn from the immunosuppressive regimen [group (G) I, n=45] or a dosage reduction only (group II, n=34). The decision to remove or to keep AZA was restricted to the patient's doctor. Patients records were reviewed by April 1997. RESULTS: After an equal time of follow-up, after the AZA changing (64+/-26 vs. 58+/-29 months), patients in GI showed a significant decrease in the serum liver parameters when compared to baseline [alanine aminotransferase (ALT): P=0.001; gamma-glutamyl transferase (gamma-GT): P=0.001 and total bilirubin: P=0.002], whereas in GII only ALT decreased (P=0.04) although gamma-GT and total bilirubin did not. Compared to baseline, serum creatinine (SCr) increased only in GI (P=0.001) but, at last follow-up, did not differ from GII. The intention-to-perform liver biopsies was equal in GI and GII (16 vs. 14) but the hystological findings of severe chronic liver disease (either chronic active hepatitis or cirrhosis) were more frequent in GII (P=0.004). Death with a functioning graft was much more frequent in GII than in GI (P=0.001). Infection and cirrhosis were more common as a cause of death in GII than in GI. CONCLUSIONS: The use AZA is harmful to renal transplantation patients with both chronic hepatitis C and B and, therefore, should be avoided. AZA withdrawal, but not dose adjustments, diminishes the serum liver enzymes and the progression rate of the chronic viral liver disease as well as the rate of death secondary to infection and cirrhosis.

Adult↗
PubMed1999

Histological outcome of acute cellular rejection in kidney transplantation after treatment with methylprednisolone.

BACKGROUND: Several studies comparing the response of acute cellular rejection (ACR) episodes to different corticosteroid regimens have been conducted. However, in most of them, the histological evaluation of the infiltrate and its correlation with clinical response was not studied. The clinical and histological outcomes of 37 episodes of ACR treated with methylprednisolone (MP) were studied, with the aim to determine how long the infiltrate takes to be cleared after therapy. METHODS: A total of 37 patients with biopsy-proven ACR were treated with 8 or 16 mg of MP/kg/day. Allograft biopsies were repeated at 5 and 10 days after the end of corticotherapy. Clinical and histological outcomes were compared. RESULTS: Six patients were excluded; 15 (48.4%) patients responded to therapy; the mean serum creatinine of these patients reached normal levels in the 2 weeks that followed treatment. Nine patients (60%) of this group had signs of ACR on biopsies done 5 days after corticotherapy, and four (26.7%) maintained them on the 10th day. Among 16 patients with no clinical response, none reached normal serum creatinine levels; 15 (93.7%) had signs of rejection 5 days after treatment and maintained them on the 10th day. Histological signs of ACR disappeared in 73.3% of patients with clinical response 10 days after therapy, but in only 6.3% of patients with no response (P=0.001). CONCLUSIONS: Biopsies performed 5 days after treatment show a high incidence of features of ACR; such features take on average 10 days to disappear in nearly 75% of cases with successful therapy with MP.

Adolescent↗
PubMed1998

Contribution of the expression of ICAM-1, HLA-DR and IL-2R to the diagnosis of acute rejection in renal allograft aspirative cytology.

Acute rejection is associated with a poor long-term prognosis for renal allografts. Sequential fine-needle aspiration cytology (FNAC) has been used to monitor rejection. However, FNAC diagnoses rejection only when the infiltrating cells are already damaging the graft and, in some borderline cases with a low increment of inflammatory cells in the graft, FNAC lacks the specificity to diagnose rejection. In these cases, the number of inflammatory cells within the graft can decline, stabilize or increase with time. In this study, we sought to determine whether the analysis of the expression of ICAM-I, HLA-DR and IL-2R along with borderline FNAC results increases the specificity to diagnose rejection. Of 117 FNAC samples taken from 24 patients after renal transplantation, 85 (72%) were considered suitable for cytological analysis. Of these patients, 9 (37%) did not suffer an acute cellular rejection (ACR) episode and 15 (63%) had at least one ACR episode. ICAM-1 and IL-2R were studied using an immune-peroxidase technique. The ICAM-1 results are expressed as the percentage of tubular cells in the aspirate stained with this marker and the IL-2R results are expressed as the absolute number of positively stained lymphocytes in the whole cytopreparation. With a total corrected increment (TCI) of > 3 there was a sharp increase in the specificity index for rejection that reached almost 100% at a TCI of > or = 4. Sensitivity for rejection at this level was only 20%. Between a TCI of 2.5 and 2.9 the sensitivity increased to 75%, with specificity for rejection around 75%. There was an upregulation of ICAM-1 and IL-2R when FNAC diagnosed rejection but with a large overlap of the results when compared either to normal graft or acute tubular neurosis. The mean TCI during the week preceding the rejection episode was 2.5 and the TCI reached a mean value of > or = 3 only during rejection. The peak ICAM-1 and IL-2R expression occurred during the week preceding the clinically evident rejection episode. The expression of ICAM-1 by > or = 70% of the tubular cells increased the specificity for rejection of a TCI of > or = 2.5 to 100%. In the same way, the specificity for rejection increased up to 90% when eight to ten IL-2R-positive lymphocytes were seen along with a TCI of > or = 2.5. There was no further increase in specificity after that. A specificity index of 100% for rejection could be obtained for moderate levels of both ICAM-1 (70% or more tubular cells) and IL-2R (eight or more lymphocytes). ICAM-1 expression in 70% or more tubular cells and/or IL-2R expression in eight or more lymphocytes was found in 58% of the FNAC aspirates with a TCI between 2.5 and 2.9. In conclusion, the expression of IL-2R in lymphoid cells and ICAM-1 in tubular cells was upregulated during rejection episodes and the upregulation preceded both the clinical and the routine FNAC diagnosis of rejection by 1 week. The ddition of these markers to the FNAC increased substantially the specificity of the FNAC to diagnose rejection.

Acute Disease↗
PubMed1998

Kidney transplantation: the use of living donors with renal artery lesions.

PURPOSE: A shortage of organs for transplantation has forced surgeons to optimize the use of marginal organs, such as kidneys with arterial disease. We present a retrospective study of the outcome of donors with renal artery disease and recipients of kidneys from living related and unrelated donors. MATERIALS AND METHODS: Kidneys with vascular abnormalities from healthy living donors were grafted into 11 recipients. These kidney transplants comprised 1.8% of those performed at our institution. The vascular abnormalities were aneurysms in 3 cases, atherosclerotic lesions in 4 and fibromuscular dysplasia in 4. After nephrectomy all abnormalities were corrected under hypothermic conditions during bench surgery except in 3 cases of ostial atherosclerotic plaque, which was left in the donors. The renal artery was anastomosed to the external iliac artery in 5 cases and to the internal iliac artery in 6. The ureter was reimplanted using an extravesical technique. RESULTS: All patients had immediate diuresis and no delayed post-transplant graft dysfunction was observed. One patient died of an unrelated cause and 3 had post-transplant graft function loss due to acute vasculopathy in 1, post-diarrhea with acute arterial thrombosis in 1 and recurrence of the hemolytic-uremic syndrome in 1. All remaining patients are well with median serum creatinine of 1.4 mg./dl. (normal 0.4 to 1.4). All donors are well and normotensive with normal renal function. CONCLUSIONS: The use of kidneys with arterial disease from living donors with unilateral disease is safe. Complete informed consent regarding the risks and benefits by donor and recipient is mandatory.

Adult↗
PubMed1998

Role of the peripheral renin profile in predicting blood pressure control after bilateral nephrectomy in renal-transplanted patients.

BACKGROUND: The unregulated renin release by native kidneys is one of the factors responsible for the high incidence of hypertension after renal transplantation but, even after three decades of transplantation, there is still a lack of a method to identify it as the major cause of hypertension. METHODS: We investigated whether or not peripheral renin activity, before and 90 min after 25 mg of captopril, can play this role. One hundred and five consecutive patients with SCr less than 2 mg/dl were studied 18 +/- 8 months after renal transplantation. Forty-seven of them were considered hypertensive and 58 normotensive. All hypertensive patients were submitted to the captopril test to analyse the peripheral renin activity profile. RESULTS: In the hypertensive group, 17 patients (36%) were considered Renin-pos and 30 (64%) Renin-neg. All Renin-pos (stimulated renin = 19.1 +/- 6.4 ng/ml/h) patients were submitted to bilateral nephrectomy (bNx) and re-evaluated 6 months later. All of them normalized renin activity (4.4 +/- 3.0 ng/ml/h, P = 0.0001) and 10 of 17 (60%) became normotensive and off drugs. The remaining seven (40%) decreased the number of hypotensive drugs from 2.2 +/- 0.5 to 0.5 +/- 0.7/pt/day. There was a correlation between b-Renin and dBP (r = 0.47, P < 0.05) which was lost after bNx. An 'in situ' renal-cell carcinoma was found in two cases. Serum creatinine did not change. CONCLUSIONS: This study shows that the unregulated renin-angiotensin system from the native kidneys plays a major role in the maintenance of hypertension in some patients with normal graft function and that peripheral renin activity can identify those who will benefit from bilateral nephrectomy.

Adult↗