Insertion of a double pigtail ureteral stent for the prevention of urological complications in renal transplantation: a prospective randomized study

PURPOSE: Urologists successfully use ureteral stents to protect the ureterovesical anastomosis in nontransplant patients. MATERIALS AND METHODS: We determined the value of ureteral stents in transplant patients. The frequency of urological complications (leaks, obstructions and urinary tract infections) was compared in a prospective randomized series of 194 kidney transplantations (97 with and 97 without a double pigtail ureteral stent). RESULTS: In the stent group 1 patient had a urinary leak and 35 had urinary tract infections (including 2 cases of Corynebacterium cystitis). In the no stent group 6 patients had urinary leaks, 4 had obstructions and 32 had urinary tract infections. The 1-year patient and graft survival rates were similar in both groups, and renal function at 1 year was also similar (229 versus 208 mumol./l. creatinine in the stent and no stent groups, respectively). A small number of stent related complications occurred (2 stent breakages and 1 stent migration). No stones formed in any case. CONCLUSIONS: Ureteral stent insertion significantly decreases the rate of vesicoureteral leakage and obstruction in renal transplantation.     

An immunochemical study of the antigens from Toxoplasma gondii tachyzoites obtained in different cultivation systems

Ureteral obstruction in a renal allograft, due to a variety of etiologies, is both a challenging diagnostic and therapeutic disorder. Since ureteral obstruction in a renal transplant recipient usually presents as azotemia, it must also be distinguished from acute rejection. Although ultrasound is non-invasive and readily available, the most definitive diagnostic tool is percutaneous nephrostomy tube placement with antegrade nephrostogram. A variety of therapeutic approaches are available to treat ureteral obstruction in a renal allograft. These procedures can be open (e.g., repeat ureteroneocystotomy) or utilize an endourological approach (e.g., transluminal ureteral dilatation). From an experimental standpoint, recent data in rodent models of experimental hydronephrosis demonstrate similar pathobiologic events in both the obstructed kidney and an allograft undergoing the chronic rejection process. To this end, investigation needs to be conducted to assess whether partial, unrecognized ureteral obstruction in an allograft hastens the development of chronic rejection. This would further underscore the importance of ureteral obstruction as a cause for not only acute azotemia in an allograft, but also chronic deterioration in renal transplant function.     

Optimal method of urgent decompression of the collecting system for obstruction and infection due to ureteral calculi

PURPOSE: We compare the efficacy of percutaneous nephrostomy with retrograde ureteral catheterization for renal drainage in cases of obstruction and infection associated with ureteral calculi. MATERIALS AND METHODS: We randomized 42 consecutive patients presenting with obstructing ureteral calculi and clinical signs of infection (temperature greater than 38 C and/or white blood count greater than 17,000/mm.3) to drainage with percutaneous nephrostomy or retrograde ureteral catheterization. Preoperative patient and stone characteristics, procedural parameters, clinical outcomes and costs were assessed for each group. RESULTS: Urine cultures obtained at drainage were positive in 62.9% of percutaneous nephrostomy and 19.1% of retrograde ureteral catheterization patients. There was no significant difference in the time to treatment between the 2 groups. Procedural and fluoroscopy times were significantly shorter in the retrograde ureteral catheterization (32.7 and 5.1 minutes, respectively) compared with the percutaneous nephrostomy (49.2 and 7.7 minutes, respectively) group. One treatment failure occurred in the percutaneous nephrostomy group, which was successfully salvaged with retrograde ureteral catheterization. Time to normal temperature was 2.3 days in the percutaneous nephrostomy and 2.6 in the retrograde ureteral catheterization group, and time to normal white blood count was 2 days in the percutaneous nephrostomy and 1.7 days in the retrograde ureteral catheterization group (p not significant). Length of stay was 4.5 days in the percutaneous nephrostomy group compared with 3.2 days in the retrograde ureteral catheterization group (p not significant). Cost analysis revealed that retrograde ureteral catheterization was twice as costly as percutaneous nephrostomy. CONCLUSIONS: Retrograde ureteral catheterization and percutaneous nephrostomy effectively relieve obstruction and infection due to ureteral calculi. Neither modality demonstrated superiority in promoting a more rapid recovery after drainage. Percutaneous nephrostomy is less costly than retrograde ureteral catheterization. The decision of which mode of drainage to use may be based on logistical factors, surgeon preference and stone characteristics.     

Acucise endoureterotomy for distal ureteral stenosis in a renal transplant patient

The treatment of ureteric strictures in renal transplantation used to be surgical, but has recently benefited from progress in endourology. The authors report the case of a renal transplant recipient who developed late stricture of the ureterovesical reimplantation of the transplant. After percutaneous nephrostomy, which restored good renal function, retrograde endoureterotomy was performed using an Acucise ureterotome balloon, followed by ureteric modelling on a 7F double J stent for 2 months. With a follow-up of 18 months, renal function was normal and ultrasonography showed residual hypotonia of the transplant cavities and no vesicorenal reflux was detected by retrograde voiding cystourethrography. Acucise retrograde endoureterotomy can constitute a simple endourological treatment for late ureteric strictures in renal transplantation.     

Ureteral opening pressure: a novel parameter for the evaluation of pediatric hydronephrosis

PURPOSE: The antegrade nephrostogram is an important tool in the evaluation of the upper urinary tract. However, the information currently provided by a nephrostogram is largely limited to anatomical details. To establish a meaningful pressure-flow parameter that may be incorporated into a routine nephrostogram, we evaluated the ureteral opening pressure (defined as the pressure at which contrast material is first seen beyond the suspected site of obstruction) and correlated these findings with the results of pressure-flow studies performed with an external infusion and/or furosemide induced diuresis. MATERIALS AND METHODS: A total of 52 renal units were studied under a prospective pressure-flow study protocol. All patients had grade 3 or 4 hydronephrosis (Society of Fetal Urology classification) and patient age range was 0.2 to 12 years (median 1.1). The suspected sites of obstruction were the ureteropelvic and ureterovesical junctions in 42 and 10 renal units, respectively. With the patient under general anesthesia 22 gauge percutaneous nephrostomy needles were inserted. Pressure-flow studies with an external infusion and/or furosemide induced diuresis were then performed. As the renal pelvic pressure progressively increased during the course of the pressure-flow studies, the renal pelvic pressure at which contrast material was first seen to appear distal to the suspected site of obstruction was recorded as the ureteral opening pressure. Ureteral opening pressures were compared to the results of the pressure-flow studies. RESULTS: With a positive test defined as renal pelvic pressure greater than 14 cm. water, positive ureteral opening pressures were associated with positive pressure-flow study results in 100% of the cases, regardless of which form of pressure-flow study was used or where the suspected site of obstruction was located. In contrast, negative ureteral opening pressures had specificities and negative predictive values of only 19 to 57%, depending on the form of the pressure-flow study and the suspected site of obstruction. CONCLUSIONS: An elevated ureteral opening pressure was 100% predictive of obstruction and may obviate the need for more elaborate pressure-flow analyses. However, if the ureteral pelvic pressure remained low, the possibility of a potentially significant obstruction could not be definitively eliminated and further evaluation was required.     

Experience with the Mainz modification of ureterosigmoidostomy

BACKGROUND: The purpose of this study was to report experience with the revived surgical concept of ureterosigmoidostomy in its low pressure modification and to discuss its value within the current spectrum of urinary diversion. METHODS: Between February 1992 and September 1997 modified ureterosigmoidostomy (rectosigmoid pouch; Mainz pouch II) was performed in 34 patients aged 1.9-76.9 (mean 55.8) years as a primary urinary diversion after radical cystectomy for bladder cancer (n = 30) and benign conditions (bladder exstrophy, three patients; intractable urinary incontinence, one). All patients were followed prospectively according to a standard protocol including assessment of continence, renal function and acid-base balance. RESULTS: There were no perioperative deaths. In one patient dislocation of a ureteral stent in the early postoperative course required insertion of a percutaneous nephrostomy. All patients were continent during the day. One patient experienced night-time incontinence but rejected a conversion procedure. In one case ureterosigmoidostomy was replaced by an ileal conduit after several episodes of septicaemia. One nephrectomy was performed for ureterointestinal obstruction. Mild hyperchloraemic acidosis was seen in two patients. CONCLUSION: Bowel frequency and urge incontinence, the major weaknesses of classical ureterosigmoidostomy, can be overcome by detubularization of the rectum. As the modified procedure is quick, safe and easy to perform with highly satisfactory results, the rectosigmoid pouch has potential in reconstructive urology.     

Management of the complications of ureterointestinal reimplantation in urinary diversion

OBJECTIVE: To analyze our experience in the management of complications of ureteroenteric reimplantation in patients undergoing urinary diversion by endourological techniques or open surgery, in order to identify a useful algorithm that takes the oncologic prognosis into account, as well as the probability of success. METHODS: A retrospective study was conducted on 136 patients who had undergone urinary diversion from 1987-1998. Of these, 126 had transitional cell carcinoma, two had infiltrating carcinoma, two had a benign condition and 6 had undergone urinary diversion for patient comfort without cystectomy. The following techniques were utilized: cutaneous ureteroileostomy or Bricker technique (104 patients), Mainz neobladder (10 patients), ileal neobladder (15 patients), colonic conduit (5 patients) and cutaneous ureter (2 patients). RESULTS: Overall, 56 patients (41%) had some type of alteration at the ureteroenteric reimplantation site, but only 36 (26%) required intervention. The reimplantation techniques utilized were: the Bricker direct ureteroileostomy (26 patients), Le Duc (6 patients), Leadbetter (3 patients), and the direct cutaneous technique (1 patient). Patient mean age was 67 years (range 53-80). There were 35 males and one female. Seven patients required immediate reimplantation due to a persistent urinary fistula and 29 had late obstruction (more than 3 months), accounting for 21.3% of the cases undergoing urinary diversion. The antegrade endourological approach was utilized in 24 patients (5 nephrostomy alone and 19 stent or balloon dilatation). Dilatation was performed palliatively in 6 cases with extensive tumor spread. Permanent success was achieved in 5 cases (38%) and in spite of the initial success, there were 4 reobstructions. Open surgery was performed in 24 patients (66% of the complicated reimplantations); 5 of these patients had another pathology that warranted laparotomy, 7 required reimplantation early due to a fistula and two patients with a nonfunctioning kidney underwent nephrectomy. Ureteral replacement using the ileum was performed in 4 patients and direct reimplantation to the primary loop was performed in 6 patients. Good surgical results were consistently achieved. CONCLUSIONS: The complication rate of ureteral reimplantation is high in patients undergoing urinary diversion. Endourology has an important role in these cases, particularly in patients with a poor prognosis. Surgery achieves the best results. Although they may entail difficulty, complex cases such as extensive ureteral necrosis can be managed successfully.     

Three cases of hydronephrosis in which the indwelt ureteral stent was ineffective. Urodynamic studies using a stent indwelling model for retroperitoneal fibrosis

We report 3 cases in which ureteral stents were indwelt to treat hydronephrosis due to retroperitoneal fibrosis, resulting in aggravation of hydronephrosis and renal function. An urodynamic study was carried out to determine the factors that aggravated hydronephrosis. The subjects were a 59-year-old male with prostatic cancer and bilateral hydronephrosis due to intrapelvic lymph node metastasis, a 49-year-old female with retroperitoneal lymph node metastasis and bilateral hydronephrosis following surgery for stomach cancer, and a 65-year-old male with hydronephrosis due to idiopathic retroperitoneal fibrosis. Indwelling of ureteral stents in the 3 patients resulted in aggravation of hydronephrosis and renal function. Stent indwelling models of retroperitoneal fibrosis were produced using adult mongrel dogs. A pressure flow study was carried out through the nephrostomy in each experimental model to determine the intrapelvic pressure and urine volume. In all stent indwelling models, the urine volume showed changes similar to those in the controls. In the stent indwelling models, the intrapelvic pressure showed a significant increase with an increase in the volume of water instilled through the nephrostomy in the stent indwelling models with retroperitoneal fibrosis, unlike the controls and models with ureteral stenosis. In conclusion, the clinical cases and model experiment suggested that unlike partial ureteral stenosis, in ureters in which extensibility was disturbed in an extensive area, the indwelt stent caused an increase in the resistance of the liquid flowing in the ureter, aggravating hydronephrosis.     

Distal ureteral atresia associated with crossed renal ectopia with fusion: recovery of renal function after release of a 10-year ureteral obstruction

We report on a 10-year-old boy with distal ureteral atresia associated with crossed renal ectopia with fusion. He was admitted with a high fever associated with a urinary tract infection. The diagnosis was established by antegrade and retrograde pyelography. The upper hydronephrotic portion of the kidney, obstructed for 10 years, recovered its function after nephrostomy placement. To our knowledge, this is the first patient whose renal function has recovered despite an ureteral obstruction of 10-years' duration. Therefore, we recommend a transient nephrostomy placement even for far advanced pediatric hydronephrosis, to test for the possibility of functional recovery.     

Lower pole calicostomy for the management of iatrogenic ureteropelvic junction obstruction

It is often possible to use endoscopic techniques for the management of iatrogenic upper ureteral or ureteropelvic junction obstruction. However, in some cases with severe stricture disease or significant ischemic injury open surgical reconstruction is necessary. We report our experience with ileal ureter-lower pole calicostomy for the management of these complex urological injuries. During the last 3 years we treated 3 patients with severe ureteral/ureteropelvic junction obstruction secondary to iatrogenic injuries, including ureteral avulsion during ureteroscopic stone extraction, ureteral laceration during dilation for diagnostic ureteropyeloscopy, and ureteral ligation with ureteropelvic junction disruption and large peri-pelvic urinoma. In all cases unsuccessful attempts at endoscopic management necessitated open repair. Lower pole heminephrectomy was performed in all patients to expose the lower pole calix and ileal ureter-lower pole calicostomy was created due to the injury of large segments of the ureter. Satisfactory results were demonstrated on postoperative excretory urography and by a lack of symptoms. Followup averaged 23 months (range 20 to 26) with stable renal function in all patients. We believe that ileal ureter-lower pole calicostomy represents an attractive alternative for the management of severe ischemic, iatrogenic upper ureteral or ureteropelvic junction obstruction when endoscopic maneuvers are not possible or ineffective.     

Modified ileocolonic bladder: 5 years of experience

A total of 25 patients 17 to 78 years old (mean age 61 years) underwent bladder replacement with a modified ileocolonic bladder: 20 underwent construction of the neobladder following cystoprostatectomy for invasive bladder tumor, 4 after cystectomy for severe interstitial cystitis and 1 for undiversion. There were 21 men and 4 women. Followup ranged from 3 to 66 months. There were no perioperative deaths. The early complication (perioperative 3 months) and late complication rates were 18% and 16%, respectively. Complications included ureterocolonic anastomotic strictures in 4 ureters (3 were treated via endoscopic retrograde balloon dilation and 1 with endourological antegrade dilation), urethral strictures in 2 patients, treated by urethral dilation, pancreatitis 2 weeks postoperatively in 1 and mild hypercholoremia without concomitant acidosis in 2. One patient presented 3 years postoperatively with a left mid ureteral stone that was managed by ureteroscopic extraction. Three patients died of recurrent carcinoma (none with urethral recurrence). The daytime continence rate was 100% and the nighttime continence rate was 92%. The ureters in this modified ileocolonic bladder were placed in an anatomically correct position to resemble a trigone near the mouth of the neobladder with the left ureter uncrossed. This placement provided easy visualization and instrumentation of the upper urinary tract. No patient had vesicoureteral reflux.     

Ureteral stricture formation after removal of impacted calculi

PURPOSE: We retrospectively evaluated the records of 21 patients a mean of 46.1 years old with ureteral stones that had been impacted for greater than 2 months to determine predisposing factors for stricture formation. MATERIALS AND METHODS: Between January 1993 and September 1996, 21 patients were referred for ureteral stones that had remained unchanged in location for at least 2 months. In 11 patients previous attempts at stone removal had failed. Each patient underwent successful stone extraction by retrograde or percutaneous antegrade ureteroscopy, or laparoscopic or open ureterolithotomy. Outcome was determined by reviewing the clinical records and radiographic studies, including excretory urography and nephrostography. RESULTS: Average duration of stone impaction before definitive treatment was 8.8 months (range 2 to 48) and mean stone size was 10.3 mm. (range 1 to 30). All stones were calcium based. There were 3 proximal, 8 mid and 10 distal ureteral calculi. At a mean followup of 7 months ureteral strictures developed in 5 patients (24%) at the previous stone site. Mean duration of stone impaction was 11 months (range 5 to 17) in patients with stricture versus 8.2 months (range 2 to 48) in those with no stricture. Four of the 5 strictures occurred in patients who had had iatrogenic ureteral perforation during previous unsuccessful attempts at stone removal. CONCLUSIONS: Ureteral stone impaction more than 2 months in duration is associated with a 24% incidence of stricture formation. Ureteral perforation at the site of the stone was identified as the primary risk factor for stricture formation in these cases.     

The treatment of staghorn calculi

Between May 1989 and November 1991, 19 staghorn calculi were treated by extracorporeal shock-wave lithotripsy (ESWL) with a Dornier MFL 5000 or Northgate SD-3. The 19 calculi were evaluated. Treatment was with monotherapy by ESWL in 9, combination percutaneous nephrolithotomy (PNL)-ESWL in 9, and nephrostomy in 1. Of the patients, 14 had a cross stent catheter pre-ESWL treatment to improve fragment evacuation. Radiologic follow up in 19 kidneys revealed that 57.9% were stone free. We arbitrarily separated our cases into 3 groups: struvite renal calculi, calcium carbonate calculi and others. Result of stone-free rate was 100% for stones consisting of struvite, and 14. 3% for stones consisting of calcium carbonate. In our opinion, the best indication of monotherapy by ESWL is for staghorn calculi, which consists of struvite, without marked dilation of pelvis and calyces.     

Severe form of familial migraine with coma

A 56-year-old woman presented with bilateral ureteral stenosis and a vesicovaginal fistula secondary to advanced cervical carcinoma. Due to the long-standing obstruction she had a non-functioning right kidney. As a first step the function of the contralateral kidney was restored by percutaneous nephrostomy; two months later endoscopic cutaneous ureterostomy was performed using a four-port retroperitoneal approach. The ureter was mobilized, transected and pulled out through a 10-mm trocar in the mid-clavicular line. The total operative time was 165 min with an estimated intraoperative blood loss of less than 30 ml. Convalescence was short.     

Comparison of primary coronary stenting to primary balloon angioplasty with stent bailout for the treatment of patients with acute myocardial infarction

This study compares the immediate and long-term outcomes of a primary coronary stenting strategy with primary balloon angioplasty with stent bailout in the treatment of patients with acute myocardial infarction (AMI). One hundred forty-seven consecutive patients who underwent primary balloon angioplasty with stent bailout (n = 94) or primary stenting (n = 53) for AMI were clinically followed for 8.1 +/- 5.7 and 8.5 +/- 4.5 months, respectively. Immediate results, as well as in-hospital and long-term ischemic events (death, reinfarction, and repeat revascularization) were compared between both groups. Angiographic success was 91.5% in the balloon angioplasty group and 94% in the stent group. In-hospital and late follow-up combined ischemic events were 22 of 94 (23%) versus 0 of 53 (0%); p < 0.001 and 33 of 78 (42%) versus 13 of 53 (25%), p = 0.04 for the balloon angioplasty and stent groups, respectively. At 6 months, the cumulative probability of repeat target lesion revascularization was higher in the balloon angioplasty group (47% vs 18%, p = 0.0006) as was the probability of late target revascularization (36% vs 18%, p = 0.046); the cumulative event-free survival after 6 months was significantly lower in the balloon angioplasty group (44% vs 80%, p = 0.0001). This study demonstrates that a primary stent placement strategy in patients with AMI is safe, feasible, and superior to primary balloon angioplasty with stent bailout. Primary stenting results in a larger postprocedural minimal luminal diameter, a lower early and late recurrent ischemic event rate, and a lower incidence of target lesion revascularization at follow-up.     

Corosolic acid isolated from the fruit of Crataegus pinnatifida var. psilosa is a protein kinase C inhibitor as well as a cytotoxic agent

We report a case of left-sided hydronephrosis and ureteropelvic urinary extravasation due to a large left iliac artery aneurysm. Urinoma was diagnosed preoperatively by contrast-enhanced computed tomography. The patient was successfully treated by percutaneous nephrostomy and ureteral double J stent placement followed by staged operative repair.     

Further experience with split-cuff nipple ureteral reimplantation in urinary diversion

PURPOSE: The intermediate followup results with split-cuff nipple ureteral reimplantation in larger numbers of urinary diversion patients are reviewed. MATERIALS AND METHODS: Split-cuff nipple ureteroenteric anastomosis was performed in 98 ureters of 51 adult patients. Mean duration of followup was 23 months (range 3 to 62). Two minor variations in technique compared to the original report are presented. RESULTS: Urinary reflux was prevented in 97.6 and 96.8% of cases at 1 and 2-year followup, respectively. Ureteroenteric anastomotic obstruction occurred in 3.1% of ureters by 3 months postoperatively. No cases of anastomotic leak or later obstruction occurred. Four episodes of acute pyelonephritis occurred in the early postoperative period. CONCLUSIONS: The split-cuff nipple ureteral reimplant technique in urinary diversion continues to provide excellent results with low rates of reflux or obstruction. The 2 described minor technical modifications further simplify the procedure.     

Serum total homocysteine concentration before and after renal transplantation

BACKGROUND: Hyperhomocysteinemia is by now an established risk factor for the development of atherosclerosis. Total homocysteine concentration (tHcy) correlates inversely with glomerular filtration rate, and it is roughly three times as high in hemodialysis patients as in healthy individuals. Therefore, tHcy would be expected to fall markedly after successful renal transplantation. The aim of the present study was to assess the changes in tHcy associated with renal transplantation. METHODS: tHcy was analyzed in samples collected before renal transplantation and at six months after transplantation in 55 stable patients, all of whom were treated with cyclosporine (CS). tHcy was also analyzed in samples from 55 controls characterized by markers of renal function that matched those of the post-transplant state. RESULTS: At six months after transplantation, tHcy was significantly decreased as compared with pretransplant tHcy (27.7 +/- 14.8 vs. 36.9 +/- 21.3 micromol/liter, P < 0.001). Post-transplant tHcy was markedly higher than the tHcy of the control group (27.7 +/- 14.8 vs. 16.0 +/- 5.3 micromol/liter, P < 0.0001). The post-transplant change in tHcy ranged widely, the average change being a reduction of 14%. Sixteen patients (29%) actually manifested an increase in post-transplant tHcy. The post-transplant changes in tHcy correlated inversely with pretransplant tHcy (r = -0.66, P < 0.0001) and directly with the changes in serum albumin concentrations (r = 0.35, P < 0.05) and CS trough concentrations (r = 0.29, P < 0.05). A multivariate analysis, including the post-transplant changes in serum concentrations of folate and albumin as well as creatinine clearances explained 21% of the change in tHcy (P < 0.05). After inclusion of the CS concentration, an independent predictor, the model accounted for 28% of the post-transplant change in tHcy (P < 0.01). CONCLUSION: The post-transplant reduction in tHcy was far smaller than expected with respect to renal function, and the post-transplant changes in the major biochemical determinants of tHcy contributed relatively little to explain the change in tHcy. Thus, the results suggest the post-transplant introduction of one or more factors that induce an increase in tHcy. Treatment with CS appears to be such a factor.     

Artificial ureteral replacement for ureteral necrosis after renal transplantation: report of 3 cases

PURPOSE: We applied a new minimally invasive technique of artificial ureteral replacement for renal transplant ureteral necrosis. MATERIALS AND METHODS: Artificial ureteral replacement was performed in 3 renal transplant recipients with ureteral necrosis (complete in 1 and distal in 2) after failure of primary endoscopic treatment. Under fluoroscopic guidance a percutaneous tract is created and progressively dilated. The ureteral silicone polytetrafluoroethylene bonded tube is introduced into the pyelocaliceal renal graft cavities, tracked subcutaneously down to the suprapubic area and introduced into the bladder via a short incision. RESULTS: There were no immediate postoperative complications except for transient postoperative acute prostatitis in 1 patient. No secondary complications were observed with a mean followup of 2.5 years. All grafts have good late function and all tubes are patent with no evidence of encrustation or obstruction. The tubes are well tolerated underneath the skin. Reflux was present in all 3 cases with no clinical manifestation. An asymptomatic episode of lower urinary tract infection was observed in the female patient. CONCLUSIONS: In select cases of ureteral necrosis after renal transplantation artificial ureteral replacement by subcutaneous pyelovesical bypass offers a possible alternative to open ureteral reconstruction.     

Bovine endometrial retinol-binding protein secretion, messenger ribonucleic acid expression, and cellular localization during the estrous cycle and early pregnancy

OBJECTIVES: We assessed the safety and efficacy of stent placement in patients with poorly controlled hypertension and renal artery stenoses, which are difficult to treat with balloon angioplasty alone. BACKGROUND: Preliminary experience with stent placement suggests improved results over balloon angioplasty alone in patients with atherosclerotic renal artery stenosis. METHODS: Balloon-expandable stents were placed in 100 consecutive patients (133 renal arteries) with hypertension and renal artery stenosis. Sixty-seven of the patients had unilateral renal artery stenosis treated and 33 had bilateral renal artery stenoses treated with stents placed in both renal arteries. RESULTS: Angiographic success, as determined by quantitative angiography, was obtained in 132 (99%) of 133 lesions. Early clinical success was achieved in 76% of the patients. Six months after stent placement, the systolic blood pressure was reduced from 173 +/- 25 to 147 +/- 23 mm Hg (p < 0.001); the diastolic pressure from 88 +/- 17 to 76 +/- 12 mm Hg (p < 0.001); and the mean number of antihypertensive medications per patient from 2.6 +/- 1 to 2.0 +/- 0.9 (p < 0.001). Angiographic follow-up at a mean of 8.7 +/- 5.0 months in 67 patients revealed restenosis (>50% diameter narrowing) in 15 (19%) of 80 stented vessels. CONCLUSIONS: Renal artery stenting is an effective treatment for renovascular hypertension, with a low angiographic restenosis rate. Stent placement appears to be a very attractive therapy in patients with lesions difficult to treat with balloon angioplasty such as renal aorto-ostial lesions and restenotic lesions, as well as after a suboptimal balloon angioplasty result.