Peter N. Bretan

Chronic renal failure: A significant risk factor in the development of acquired renal cysts and renal cell carcinoma. Case reports and review of the literature

Three male patients with end‐stage renal disease on chronic hemodialysis presented with gross hematuria and were subsequently found to have acquired renal cyst disease and progressive bilateral renal cell carcinoma. There are now more than 84 similar cases in the literature, but the precise roles that renal failure and hemodialysis play in the development of renal cysts and renal neoplasms remain unclear. The high incidence of acquired renal cyst disease (45%) and the development of renal tumors (9%, with a 5% to 7% metastatic rate) in patients with end‐stage renal failure clearly underscores the need for more intense radiologic monitoring.

UROLITHIASIS IN RENAL AND COMBINED PANCREAS/RENAL TRANSPLANT RECIPIENTS

PURPOSE Urological complications in renal transplant recipients will become more common with increasing numbers of transplantations as well as increased graft survival secondary to improvements in immunosuppression. Urinary stone disease may be one of those complications. We determine the current incidence of urinary stone disease in renal transplant patients based on contemporary immunosuppressive regimens. MATERIALS AND METHODS We reviewed the records of 1,730 renal and 83 pancreas/renal transplantations performed during the cyclosporine era and identified 8 recipients (0.4%) with urinary stone disease, including 3 with renal pelvic stones, 1 with multiple ureteral stones and 4 with bladder calculi. RESULTS Treatment ranged from conservative observation to open pyelolithotomy, and included percutaneous nephrolithotomy and extracorporeal shock wave lithotripsy. The ureteral stones were removed with antegrade and retrograde ureteroscopy. The 4 bladder stones were treated with cystolithalopaxy. No case had significant permanent graft damage. Mean followup was 68.6 months. Mean serum creatinine was 1.5 mg./dl. (normal 0.5 to 1.3) at baseline and 2.38 after followup. CONCLUSIONS While the incidence of upper tract urinary stone disease in renal (0.23%) and pancreas/renal (1.2%) transplant recipients is not statistically significant (p <0.45), the latter have significantly higher rates of bladder stones (4.8 versus 0%, p <0.001). The diagnosis of urinary stone disease in transplant recipients can be challenging because of the lack of symptoms but the treatment approach is the same as in the normal population.

Renal transplantation in patients with posterior urethral valves: favorable long-term outcome.

PURPOSE We assessed the long-term efficacy of renal transplantation in patients with posterior urethral valves. MATERIALS AND METHODS We reviewed the outcome in 23 patients with posterior urethral valves who underwent renal transplantation since 1979. RESULTS Graft survival was 69% at 5 years and 63% at 10 years. Seven patients with followup of 7 years or longer had a mean serum creatinine level of 1.5 mg/dl. Three patients (13%) demonstrated significant bladder dysfunction postoperatively. CONCLUSIONS Renal transplantation into a valve bladder is not associated with an abnormally high rate of failure. Deterioration of graft function secondary to lower urinary tract dysfunction is uncommon, with the majority of patients able to use the unmodified native bladder as a receptacle for the transplanted kidney.

Treatment of refractory kidney transplant ureteral strictures using balloon cautery endoureterotomy

OBJECTIVES To report our long-term clinical results with the use of endoureterotomy in patients undergoing renal transplant with a minimum follow-up of 23 months. METHODS Six renal transplant patients developed persistent ureteral obstruction demonstrated by elevated serum creatinine levels, renal ultrasound, and antegrade pyelography. Stent placement and balloon dilation were performed as the initial therapy in all patients. Persistent ureteral obstruction was managed with balloon cautery endoureterotomy. Ureteral stents were removed cystoscopically 6 weeks after the procedure. RESULTS Four men and 2 women, mean age 45 years (range 38 to 54), underwent eight procedures: six by way of an antegrade percutaneous approach and two in an endoscopic retrograde fashion. The sites of ureteral stricture were ureterovesical junction (n = 4), ureteropelvic junction (n = 1), and midureteroureteral (n = 1). Two patients required a second endoureterotomy 3 months after the first attempt. Patients were followed up for a mean of 27 months (range 23 to 34). The mean serum creatinine level for all patients at follow-up was 2.6 mg/dL (range 1.6 to 3.9), including a mean serum creatinine level of 1.8 mg/dL (range 1.6 to 1.9) for nonrejected kidneys and a mean of 3.4 mg/dL (range 2.5 to 3.9) in those found to have concurrent rejection. Overall, five (63%) of eight procedures were successful in 5 (83%) of 6 patients. No intraoperative complications occurred and no blood transfusions were required. CONCLUSIONS Balloon cautery endoureterotomy was successful in this select group of renal transplant patients with persistent ureteral strictures after initial balloon dilation and stenting failed. This modality proved durable to 27 months of follow-up without significant complications.

Magnetic resonance imaging in the diagnosis of acute renal allograft rejection and its differentiation from acute tubular necrosis. Experimental study in the dog.

This study was designed to evaluate the potential utility of magnetic resonance imaging (MRI) for the diagnosis of acute renal allograft rejection and its differentiation from acute tubular necrosis (ATN). Eighteen canines were used. Five animals served as controls. ATN was induced in six animals by cross-clamping of the left renal artery for 90 minutes. In order to study acute renal allograft rejection, seven animals were subjected to exchange allograft transplantation of the left kidney. MRI was performed with a 0.35T superconductive magnet. A double spin-echo technique was used with varying TR and TE parameters. The spin echo images were analyzed for morphology, signal intensity, T1 and T2 relaxation times, and spin density. The most useful MRI criteria for the diagnosis of ATN and acute rejection were found to be the renal size, the intensity difference between cortex and medulla (corticomedullary contrast), and the T1 relaxation time of the cortex. Normal kidneys showed maximal corticomedullary contrast (19% +/-2) on images obtained with TR = 0.5 sec and TE = 28 msec. Cortical T1 relaxation time was 551 msec + /-73. In the ATN group, the kidneys were slightly swollen (P = ns) and the corticomedullary contrast (11% + /-3) was reduced by 42% (P less than .01). T1 of the cortex (689 + /-142) was increased by 25% (P less than .10). In acute rejection, significant renal enlargement was noted (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of Clinical Renal Preservation by Phosphorus-31 Magnetic Resonance Spectroscopy

To evaluate the role of magnetic resonance spectroscopy (MRS) and to develop surface coils for assessing cadaveric renal viability during hypothermic storage, we used the monophosphate/inorganic phosphate ratio (MP/Pi) to monitor phosphorous metabolites in intact kidneys during various renal preservation maneuvers. Eighteen canine kidneys and 16 cadaveric kidneys were studied as follows: Group 1 (N = 4) in situ kidneys were monitored by implanted MRS coils; Group 1 (N = 4) ex vivo kidneys were immediately attached to vascular cannulas and monitored by MRS surface coils during normothermic perfusion; Group 3 (N = 4) kidneys were removed, cold-flushed and, after 24 hours of 4C storage, monitored by MRS surface coils before and during four hours of reperfusion via vascular cannulas; Group 4 (N = 6) kidneys were removed, cold-flushed and monitored by surface coils during cold storage up to 72 hours. In addition, 16 cadaveric kidneys were studied while in sterile cold-storage containers. Postoperative renal function was followed in recipient patients. The MP/Pi ratios in Group 1 kidneys correlated with the ability to regenerate adenosine triphosphate (ATP). Groups 2 and 3 showed similar regeneration of ATP and MP/Pi after postischemic reperfusion, and the signal-to-noise ratios of the surface coils were better than those in the implanted coils in Group 1. Surface-coil monitoring in Group 4 kidneys showed predictable decay rates of MP/Pi during one to 72 hours of cold storage; in contrast, simultaneous cortical medullary microcirculation studies with 99mTc-macroaggregated albumin were inconclusive. Human cadaveric kidneys with high MP levels were associated with excellent renal function after transplantation, while those with low MP (less than or equal to 0.50) were associated with nonviability. We conclude that MRS is a practical and safe diagnostic modality for clinical transplantation.

Preoperative assessment of retroperitoneal pathology by magnetic resonance imaging primary leiomyosarcoma of inferior vena cava

A woman with a retroperitoneal mass was found to have a leiomyosarcoma arising in the wall of the inferior vena cava. The extensive preoperative radiologic findings were compared with those of magnetic resonance imaging. The latter allowed a more precise preoperative diagnosis and determination of tumor origin and extent than any of the other diagnostic techniques.

SUCCESSFUL LONG-TERM OUTCOME USING EXISTING NATIVE CUTANEOUS URETEROSTOMY FOR RENAL TRANSPLANT DRAINAGE

PURPOSE We report our long-term experience with a preexisting native cutaneous ureterostomy via an ipsilateral transplant ureteral native ureterostomy for transplant drainage without native nephrectomy. MATERIALS AND METHODS Between 1993 and 1998, 5 patients without a usable bladder had undergone previously urinary diversion via cutaneous ureterostomy. All patients had a well functioning cutaneous ureterostomy for a mean plus or minus standard deviation of 18+/-12 years before renal transplantation. No patient had a history of stomal stenosis, recent urinary tract infection or pyelonephritis. RESULTS All 5 patients continued to have a functioning renal transplant at last mean followup of 36+/-6.6 months. Complications included stomal retraction due to postoperative weight gain requiring revision in 2 cases and ureteroureteral anastomotic stenosis treated with endopyelotomy in 1. Mean serum creatinine at last followup was 1.5+/-0.6 mg./dl. CONCLUSIONS Of the complications that we present only 1 may be attributed to the singularity of our procedure. Our experience suggests that a preexisting native cutaneous ureterostomy may serve as a receptacle for transplant ureteral drainage in select patients with excellent long-term function.

Assessment of male infertility: correlation between results of semen analysis and phosphorus-31 magnetic resonance spectroscopy

To evaluate the usefulness of phosphorus-31 magnetic resonance spectroscopy (31P-MRS) in assessing male infertility, we compared it with conventional semen analysis. Specimens were obtained from otherwise healthy patient groups as follows: group A, 7 fertile control subjects; group B, 12 azoospermic men after vasectomy; and group C, 11 patients presenting for infertility evaluation. Correlations between established semen analysis parameters and the 31P-MRS-derived ratio of glycerylphosphorylcholine to total phosphate (GPC/TP) were investigated. Group A controls had a mean GPC/TC ratio of 0.10 +/- 0.05, which was the same as that of group C. With the exception of significantly lowered motility and normal morphology in group C (p less than 0.001 and 0.05, respectively) semen analysis parameters in these two groups were similar. In contrast, the GPC/TP ratio in group B (0.05 +/- 0.04) was significantly different from the control (p less than 0.05), which appropriately reflected complete vasal occlusion. The results suggest that a significant portion of seminal GPC is derived from epididymal secretion and that 31P-MRS is useful for monitoring the GPC/TP levels when assessing epididymal function and male infertility.

Complex renal reconstruction

This article provides a complete review of current renal reconstructive techniques. The techniques described include partial nephrectomy, intrasinusal surgery, anatrophic nephrolithotomy, nonvascular bench procedures with autotransplantation, and allograft partial nephrectomy in renal transplantation. A detailed discussion on renovascular and collecting system anatomy and current indications for these procedures is presented.