Ureteral stent displacement associated with deep massage

A 51 year-old woman with a history of ureteral stenosis and calculi noted recurrence of severe left flank pain while undergoing a deep body massage using the Rolfing method. Displacement of her left ureteral double J stent was noted in the emergency department. The pain and associated incontinence resolved with restoration of the stent to its original position. Practitioners should be aware of this potential complication related to forceful massage pressures.     

MR imaging of the liver with Resovist: safety, efficacy, and pharmacodynamic properties

PURPOSE: To determine whether ultrasound (US) is a sensitive follow-up method after placement of a carotid artery stent for the detection of significant stenosis, occlusion, and other complications at early and intermediate follow-up. MATERIALS AND METHODS: Doppler US examinations were performed after stent placement in 170 carotid arteries in 119 patients with angiographic correlation. Prospective diagnostic US criteria for stenosis were peak-systolic velocity greater than 1.25 m/sec, internal carotid artery (ICA) to common carotid artery (CCA) peak-systolic velocity ratio of greater than or equal to 3:1, and intrastent doubling of peak-systolic velocity. Retrospective criteria for stenosis were also applied: peak-systolic velocity greater than 1.7 m/sec, ICA end-diastolic velocity greater than 0.4 m/sec, ICA/CCA peak-systolic velocity ratio greater than 2.0, and ICA/CCA end-diastolic velocity ratio greater than 2.4. RESULTS: Eighty-seven immediate and 83 intermediate (average, 7.3 months) follow-up US examinations were performed. Two stent occlusions were detected. One or more prospective US criteria were abnormal in 26 arteries with a stent. One or more retrospective criteria were positive in 47 arteries. Angiography showed corresponding findings, with only one significant stenosis (63%) in the ICA stents. Moderate collapse of a CCA stent was depicted at US. CONCLUSION: Only one significant recurrent stenosis was detected, and no significant stenoses were missed at US. US successfully depicted carotid artery stent occlusion and a moderate stent collapse. Sensitivity in the detection of intrastent stenosis is promising. Further study to refine US criteria in a study with longer term follow-up is needed owing to the lack of significant recurrent stenosis in the intermediate follow-up group.     

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.     

The placebo in modern medicine

PURPOSE: To report the results of balloon angioplasty in recurrent carotid occlusive disease and evaluate the potential for stent implantation. METHODS AND RESULTS: Between April 1991 and September 1995, 15 patients with carotid restenosis underwent 17 endoluminal procedures in 3 common carotid and 14 internal carotid arteries. Two postdilation complications (dissection and acute occlusion) required prompt stenting; one common carotid artery was stented for postdilation residual stenosis. One recurrent lesion was also stented 6 months after initial angioplasty. One stroke, 1 silent cerebral infarction, and 3 transient ischemic attacks occurred in the balloon angioplasty patients (33% neurological complication rate). The common carotid stent patient died 3 days postoperatively due to hyperperfusion syndrome. Long-term follow-up in two stent patients showed no restenosis at 18 and 48 months, respectively. The 11 balloon angioplasty patients likewise have not demonstrated restenosis. CONCLUSIONS: Balloon angioplasty alone appears too risky for treating recurrent carotid disease. Stents may offer a safer alternative, particularly when implanted primarily.     

Role of coronary artery spasm in progression of organic coronary stenosis and acute myocardial infarction in a swine model. Importance of mode of onset and duration of coronary artery spasm

BACKGROUND: Coronary spasm may play an important role in progression of organic coronary stenosis and myocardial infarction, but the mechanisms responsible for these complications are not known. This study aimed to examine whether the mode of onset and the duration of coronary spasm influenced progression of organic coronary stenosis and acute myocardial infarction in a swine model of coronary spasm. METHODS AND RESULTS: G?ttingen miniature pigs were subjected to cholesterol feeding, balloon-induced coronary arterial denudation, and x-ray irradiation. Five months later, coronary spasm was induced by intracoronary injection of serotonin. In 10 pigs, coronary spasm was provoked abruptly and maintained for 25 minutes by five repeated intracoronary injections of serotonin (10 micrograms/kg) every 5 minutes (group A, abrupt onset and short duration). In group B, coronary spasm was provoked gradually by intracoronary injections of serotonin at graded doses of 0.1, 0.3, and 0.6 microgram/kg every 5 minutes and was then maintained for 25 minutes in four pigs (group B1, gradual onset and short duration) and for 120 minutes in six pigs (group B2, gradual onset and long duration) by repeated intracoronary injections of serotonin (10 micrograms/kg) every 5 minutes. Intramural hemorrhage was noted histologically at the spastic site more frequently in group A with abrupt onset (nine of 10 pigs) than in group B with gradual onset (two of 10 pigs) (p < 0.01). Progression of organic coronary stenosis due to intramural hemorrhage was noted in seven pigs (six pigs in group A and one pig in group B), including three cases of total coronary occlusion. Evidence for the evolution of acute myocardial infarction (serial ECG findings, left ventriculograms, and histological findings) was noted in one pig (7%) of group A or B1 with short duration and in five of six pigs (83%) in group B2 with long duration (p < 0.01 versus group A and B1). CONCLUSIONS: These results indicate that: 1) intramural hemorrhage was frequently induced by coronary spasm of abrupt but not of gradual onset, 2) intramural hemorrhage resulted in acute progression of coronary stenosis and sometimes resulted in persistent total coronary occlusion leading to acute myocardial infarction, and 3) prolonged coronary spasm resulted in acute myocardial infarction without progression of organic coronary stenosis.     

Comparison of brain tissue metabolic changes during ischemia at 35 degrees and 18 degrees C

BACKGROUND: We evaluated brain tissue oxygen pressure (PO2), carbon dioxide pressure (PCO2) and pH during ischemia with brain temperature at 35 degrees and 18 degrees C in the same patient. METHODS: Surgery was performed in a 60-year-old woman to clip a large aneurysm in the left internal carotid artery (ICA). A Paratrend 7 probe measuring PO2, PCO2, and pH was inserted into tissue at risk for ischemia during ICA occlusion and brain protection was provided with 9% desflurane. One week later, hypothermic circulatory arrest with brain temperature at 18 degrees C was performed for aneurysm clipping and tissue measurements were obtained during ischemia and rewarming. RESULTS: At 35 degrees C, ICA occlusion for 16 minutes produced tissue hypoxia (PO2 = 0) and acidosis (pH = 6.70). The rate of increase of hydrogen ion (H+) reached 50 nEq.L(-1).min(-1) during ICA occlusion and there was a slow recovery of acidosis at the end of the ischemic period. During hypothermic circulatory arrest, tissue PO2 was sensitive to decreases in blood pressure and decreased rapidly during exsanguination. Although tissue pH decreased to 6.5 with 30 min of no pump flow, the rate of H+ increase during hypothermic arrest was one-third of that seen during ischemia at 35 degrees C. During rewarming from profound hypothermia, two phases of recovery from acidosis were observed, one during CO2 clearance and one after tissue reoxygenation. Recovery of acidosis occurred sooner at 18 degrees C than at 35 degrees C. CONCLUSIONS: These results show that tissue acidosis develops more slowly and recovers more rapidly with hypothermic ischemia. This may be an important mechanism of reduced ischemic injury during hypothermia.     

Gradual occlusion of extrahepatic portosystemic shunts in dogs and cats using the ameroid constrictor

Gradual occlusion of the splenic vein, using a specialized device (ameroid constrictor), was evaluated experimentally in three normal beagle dogs. Splenoportograms were used to verify that total occlusion of the splenic vein had occurred in all dogs within 4 to 5 weeks after application of the device. The ameroid constrictor (AC) was also evaluated as a method of gradual vascular occlusion in 12 dogs and two cats with single, extrahepatic, portosystemic shunts (PSS). Serum bile acid (SBA) concentrations were measured and portal scintigraphy (PS) was performed on all 14 animals preoperatively and 10, 20, 30, and 60 days postoperatively. Two dogs (14%) died from portal hypertension in the early postoperative period. One dog and one cat developed multiple acquired PSS, confirmed by mesenteric portography 90 days after the operation. Portal scintigraphy confirmed total occlusion of the primary shunt in the other 10 animals. Shunt fractions (SF), as measured by PS on postoperative days 30 and 60, declined significantly from preoperative values. Significant decreases were noted between preoperative and postoperative values for preprandial SBA on postoperative day 60 and for postprandial SBA on postoperative day 30. SBA concentrations did not correlate with SF. Based on this study, gradual vascular occlusion using the AC is recommended as a method for treatment of single, extrahepatic, PSS.     

An effective technique to facilitate radiographic stone visualization with an internal stent during shock wave lithotripsy

PURPOSE: We describe a simple method to assist stone localization during shock wave lithotripsy in the presence of a Double J stent. MATERIALS AND METHODS: A 4F whistle tip ureteral catheter is passed alongside a previously inserted 6F Double J stent. The tip of the ureteral stent is positioned in the lower or mid third of the ureter. Contrast material is injected through the ureteral catheter during lithotripsy to assist stone localization. RESULTS: This technique has been successful in localization of poorly opacified renal stones during lithotripsy. CONCLUSIONS: Radiolucent and poorly calcified renal stones can be easily localized during shock wave lithotripsy, despite the presence of a Double J stent. No special catheters or stents are required for this technique.     

Free ureteral replacement in rats: regeneration of ureteral wall components in the acellular matrix graft

OBJECTIVES: To evaluate ureteral replacement by a free homologous graft of acellular matrix in a rat model. METHODS: In 30 male Sprague-Dawley rats, a 0.3 to 0.8-cm midsegment of the left ureter was resected and replaced with an acellular matrix graft of equal length placed on a polyethylene stent. The animals were killed at varying intervals, and the grafted specimens were prepared for light and electron microscopy. RESULTS: In all animals, the acellular matrix graft remained in its original position without evidence of incrustation or infection, and histologic examination showed complete epithelialization and progressive infiltration by vessels. At 10 weeks, smooth muscle fibers were observed; at 12 weeks, nerve fibers were first detected; at 4 months, smooth muscle cells had assumed regular configuration. CONCLUSIONS: The ureteral acellular matrix graft appears to promote the regeneration of all ureteral wall components.     

Major benefit from antiplatelet therapy for patients at high risk for adverse cardiac events after coronary Palmaz-Schatz stent placement: analysis of a prospective risk stratification protocol in the Intracoronary Stenting and Antithrombotic Regimen (ISAR) trial

BACKGROUND: The Intracoronary Stenting and Antithrombotic Regimen (ISAR) Trial is a randomized study in which antiplatelet therapy is compared with anticoagulant therapy after coronary stent placement, showing a significantly lower rate of noncardiac and cardiac events with antiplatelet therapy. The present study is a report of the analysis of a prospective risk stratification protocol in the ISAR Trial and the association with the incidence of adverse cardiac events and stent vessel occlusion. METHODS AND RESULTS: In all 517 patients randomized in the ISAR Trial, risk stratification was done with a list of 18 clinical, procedural, and angiographic variables: 165 patients with two or fewer criteria were classified as low risk, 148 patients with three criteria were classified as intermediate risk, and 204 patients with four or more criteria were classified as high risk. Within a 30-day follow-up, cardiac event rate (death, myocardial infarction, repeat intervention) was 6.4% for high-risk, 3.4% for intermediate-risk, and 0% for low-risk patients (P<.01). Stent vessel occlusion occurred in 5.9%, 2.7%, and 0%, respectively (P<.01). There was no significant difference between anticoagulant and antiplatelet therapy in the low- and intermediate-risk groups. In high-risk patients, however, the cardiac event rate was 12.6% with anticoagulant therapy and 2.0% with antiplatelet therapy (P=.007), and the rate of stent vessel occlusion was 11.5% and 0%, respectively (P<.001). CONCLUSIONS: This risk stratification protocol can help to identify patients at risk for adverse cardiac events and stent vessel occlusion. Patients in the high-risk group had the most benefit from antiplatelet therapy. These data suggest that antiplatelet therapy is the therapy of choice after coronary stenting specifically for patients with acute ischemic syndromes, difficult procedures, or suboptimal final results.     

Changes in myocardial electrical impedance induced by coronary artery occlusion in pigs with and without preconditioning: correlation with local ST-segment potential and ventricular arrhythmias

BACKGROUND: Myocardial ischemia increases tissue electrical resistivity leading to cell-to-cell uncoupling, and this effect is delayed by ischemic preconditioning in isolated myocardium. Alterations in myocardial resistivity elicited by ischemia in vivo may influence arrhythmogenesis and local ST-segment changes, but this is not well known. METHODS AND RESULTS: Myocardial impedance (resistivity [omega x cm] and phase angle [degrees]), epicardial ST segment, and ventricular arrhythmias were analyzed during 4 hours of coronary artery occlusion in 11 anesthetized open-chest pigs; these were compared with 13 other pigs submitted to a similar coronary occlusion preceded by ischemic preconditioning. Myocardial resistivity rose slowly during the first 34+/-7 minutes of occlusion (237+/-41 to 359+/-59 omega x cm), increased rapidly to 488+/-100 omega x cm at 60 minutes, and reached a plateau value (718+/-266 omega x cm, ANOVA; P<.01) at 150+/-69 minutes. By contrast, phase-angle changes began after 17 minutes of ischemia (-3.0+/-1.6 degrees to -4.2+/-1.2 degrees at 29+/-8 minutes) and evolved faster thereafter (-12.5+/-5.3 degrees at 144+/-56 minutes). Marked changes in myocardial impedance were observed during the reversion of ST-segment elevation that occurred 1 to 4 hours after occlusion, but impedance changes were less apparent during the early ST-segment recovery seen at 15 to 35 minutes of ischemia. The second arrhythmia peak (30+/-5 minutes) coincided with the fast change in tissue impedance, and both were delayed (P<.05) by ischemic preconditioning. CONCLUSIONS: A rapid impairment of myocardial impedance occurs after 30 minutes of coronary occlusion, and its onset is better defined by shift in phase angle than by rise in tissue resistivity. Phase 1b arrhythmias are associated with marked impedance changes, and both are delayed by preconditioning. Reversion of ST-segment elevation is partially associated with impairment of myocardial impedance, but other factors play a role as well.     

A new self-expanding lined stent-graft in the dog ureter: radiological, gross, histopathological and scanning electron microscopic findings

Recurrent or intractable ureteral strictures pose a significant problem for the practicing urologist. Metallic stents have been used sparingly for this problem with varying success. We investigated the use of a stent-graft consisting of a metal stent lined with a porous biocompatible polymer to determine if the liner would prevent urothelial ingrowth. One ureter of each of 11 dogs was treated with either a metallic woven stent or stent-graft inserted retrograde via a midline cystotomy. Six bare wire stents (controls) and five lined with a new, porous, biocompatible, polycarbonate elastomer liner (Corethane) were placed. The animals were followed radiographically with intravenous urography (IVP) at 6 weeks and just prior to sacrifice (12 to 22 weeks). Gross, histological, and electron microscopic analyses were performed. The results demonstrate that all of the bare metal stented animals developed moderate to severe hydroureteronephrosis with significant urothelial hyperplasia and ingrowth through the spaces between the metal wires. The animals implanted with lined stents showed one instance of mild hydroureteronephrosis (observed radiographically but not grossly at time of sacrifice) and virtually no papillary in-growths of urothelium through the stent interstices. This obstructive phenomenon was prevented by the porous polymer lining. There was no evidence of biodegradation of the liner on scanning electron microscopy. Based upon these findings, the marriage of a biocompatible polymer which provokes minimal tissue reaction, and metallic stents which provide tremendous strength, seems to offer significant advantages when placed into the urinary tract to maintain ureteral luminal patency.     

Efficacy of Doppler ultrasonography for assessment of transjugular intrahepatic portosystemic shunt patency

PURPOSE: To assess the efficacy of Doppler ultrasonography (US) as a noninvasive method for monitoring patency of the transjugular intrahepatic portosystemic shunt (TIPS). METHODS: Twenty-nine patients who had received TIPS for bleeding esophagogastric varices and/or refractory ascites with portal hypertension underwent Doppler US studies within 2 weeks after TIPS. Further studies were performed in 15 of them at 6 months, in 9 at 1 year, and in 4 at 2 years for a total of 57 US studies. The US findings were compared with the angiographic findings obtained at the same time. RESULTS: In 45 of the 57 studies, shunt patency was found by Doppler US, correlating to 44 patencies and one occlusion on angiography. Doppler signal in the shunt could not be detected in 12 studies resulting in the diagnosis of shunt occlusion. This correlated with angiographic occlusion in 8 studies and patency in the remaining 4. All angiographically patent shunts that were occluded by Doppler US had various degrees of stenosis. A number of technical factors were found to be responsible for Doppler US false-positive or false-negative diagnoses, some related to the type of stent used. The Doppler US sensitivity was therefore 92%, the specificity 89%. CONCLUSION: Doppler US is a reliable noninvasive method to evaluate patency of TIPS.     

Cytokine-induced sequential migration of neutrophils through endothelium and epithelium

RATIONALE AND OBJECTIVES: To evaluate different vein graft-coated stent systems in the endovascular treatment of experimental arteriovenous fistulae (AVF) in a canine model. METHODS: Bilateral carotid-to-external jugular vein AVF were created. Two balloon-expandable tantalum stents (Strecker stent), two self-expanding nitinol stents (Strecker stent), and one stainless-steel stent (Wallstent) were coated with autologous vein grafts and placed using a transfemoral approach. Angiography was performed immediately after stent placement and at week 1 and 3, as well as at months 3, 6, and 9. All stents were removed and underwent histologic examination. RESULTS: Occlusion of the AVF succeeded with the Wallstent and both tantalum stents. The nitinol stents were misplaced, maintaining the AVF. One undersized tantalum stent and the Wallstent were occluded after 3 weeks. One nitinol stent was occluded at 3 months, whereas the two remaining stents were patent during the whole observation period. No inflammatory tissue response was seen, and no host-versus-graft reaction was present. CONCLUSIONS: Preparation and implantation of vein graft-coated stents, especially in the case of self-expanding stent systems, is cumbersome. This restricts the common use of such a coating, which shows an excellent biocompatibility. Vein graft-coated stents might be of use in infected endangered vessels.     

Update on the use of percutaneous nephrostomy/balloon dilation for the treatment of renal transplant leak/obstruction

PURPOSE: Retrospective evaluation of the efficacy of percutaneous nephrostomy and nephroureteral stent placement for treatment of post-transplant ureteral leak, and percutaneous nephrostomy and balloon dilation for treatment of post-transplant ureteral obstruction. PATIENTS AND METHODS: Data were reviewed for all patients who underwent percutaneous therapy for complications after renal transplantation between January 1985 and June 1995. A total of 61 patients with complications (leak, n = 17; obstruction, n = 44) had been treated. Patients underwent percutaneous nephrostomy followed by antegrade placement of a nephroureteral stent. In addition, all patients with obstruction also underwent ureteral balloon dilation. Follow-up ranged from 9 weeks to 24 months. Positive outcome was defined as nonsurgical closure of leak, significant improvement in renal function, and removal of the nephroureteral stent with maintenance of stable renal function. RESULTS: Regarding ureteral leak, 10 of 17 patients (59%) healed after treatment. Seven patients (41%) did not respond and went on to surgical repair. All patients with early (n = 13) ureteral obstruction (< 3 months after transplantation), had improved renal function (P < .025). Sixty-two percent of patients with early obstruction were cured (tube out with stable renal function) and 38% went to surgery for ureteral repair. In patients with late (n = 31) obstruction (> 3 months after transplantation), renal function improved in only 58% (P < .01). Only 16% of patients with late obstruction were cured (tube out with stable renal function). Ureteral obstruction was persistent in the remaining patients and did not respond to multiple balloon dilations. All complications were minor and included 23 of 61 (38%) patients with urinary tract infections and nine of 61 (14%) patients with limited hematuria. CONCLUSION: Percutaneous nephrostomy is very effective in improving renal function in patients with early obstruction. It is moderately successful in treating ureteral leak. Ureteral balloon dilatation is moderately effective for treatment of obstruction in the early (< 3 months) postoperative period. However, balloon dilation is minimally successful in curing ureteric obstruction occurring more than 3 months after transplantation.     

Insulin levels after portal and systemic insulin infusion differ in a dose-dependent fashion

BACKGROUND: Before the advent of the falloposcope, the endosalpinx usually evaded endoscopic evaluation. The healthy condition of the tubal epithelium and the patency of the tube are important for development and transportation of early stage embryos. METHODS: Twenty patients had tubal occlusion diagnosed by hysterosalpingography, including 10 cases of hydrosalpinx, five cases of interstitial occlusion and five cases of fimbrial occlusion. Falloposcopy with a linear everting catheter and laparoscopy were performed simultaneously to evaluate tubal lumens and peritubal conditions. RESULTS: An attempt was made to cannulate 30 fallopian tubes in 20 cases with a falloposcope, using a nonhysteroscopic transvaginal approach through a linear everting catheter. The success rate was 93% (28/30). In 15 cases of hydrosalpinx or fimbrial obstruction, 10 patients (67%) were considered to be suitable for in vitro fertilization because of flattened mucosa in the endosalpinx and endotubal adhesions. Normal mucosa was noted in only four patients (27%), who were advised to have tuboplasty. One patient (6%) had normal mucosa without tubal occlusion. In two of the five cases of interstitial occlusion, dye (methylene blue) could not pass the interstitial portion of the fallopian tube when chromopertubation was performed twice. This tubal obstruction was overcome with the linear everting catheter. One patient had the complication of an ampulla wall perforation. CONCLUSIONS: In patients with fallopian tube disease, falloposcopy is a useful technique for evaluating the endosalpinx and providing information for selecting further treatment. In some cases of interstitial occlusion, it may also have a therapeutic effect.     

Palliative endoscopic treatment of proximal malignant biliary stenosis

24 patients (median age 71.5 years) with inoperable proximal malignant biliary obstruction were treated by insertion of endoscopic endoprostheses from January 1991 to August 1994. 10 patients had gallbladder cancer, 6 cancer of body or tail of pancreas, 5 cholangiocarcinoma and 3 other metastatic malignancy, respectively. 13 patients had type I, 10 had type II and 1 had type III proximal biliary stenosis (Bismuth classification). Stent occlusion or dislocation required a secondary stent insertion in 9 patients. In all cases there was adequate biliary drainage after stent insertion. Complications were: early cholangitis developed in 2 patients, late cholangitis in 5, stent dislocation in 3. One patient underwent an operation because of necrotising cholecystitis and subhepatic abscess. There was no bleeding, retroperitoneal perforation or pancreatitis. 18 patients died (median survival time 28 weeks) and 6 have been alive at the time of review for 15 weeks in average. Endoscopic stent insertion can be applied effectively also in the palliative treatment of proximal malignant biliary obstruction.     

Results and complications after endovascular reconstruction of aortic aneurysms

Between August 1994 and December 1996 137 patients (10 female and 127 male, mean age 66 yrs., range 27-85) with aortoiliac aneurysmal disease were treated with endovascular stent grafts. Pathology included 5 thoracic, 131 abdominal and 1 isolated iliac artery aneurysm. 88 straight tube grafts (75 Mintec, 12 EVT, 1 Chuter) and 43 bifurcated grafts (21 Mintec, 20 EVT, 2 Chuter) were implanted in the infrarenal aorta. 5 (Mintec) tube grafts were used for the thoracic aneurysms. One tapered tube graft was used to exclude the isolated iliac aneurysm. 11 patients (8%) required conversion to open surgical repair. This was due to defective devices in 5, device related occlusion of a renal artery in 2, aortic dissection in 1, occlusion of iliac outflow in 1, a large unmanageable proximal endoleak in 1 and a retroperitoneal bleeding resulting in hemorrhagic shock in 1 patient. There was one procedure related death for a mortality of 0.7%. Patients were followed every 3-6 months using CT with i.v. contrast and ultrasound duplex examinations with adjunctive usage of an intravenous ultrasound contrast agent (Levovist, Schering AG). Intraarterial DSA was used only when called for by thrombotic or stenotic complications. At a mean follow-up of 9.2 months (range 2-24 months) 16 (17%) primary and 8 (8.5%) secondary leaks (at the distal anchoring zone) were detected after implantation of tube grafts. 11 (25.6%) leaks were detected after implantation of bifurcated grafts. Iliac artery occlusion was observed in 2 patients after placement of a straight endograft, 6 times after reconstruction with a Mintec bifurcated device and 3 times after implantation of an EVT bifurcated endograft. Successful treatment of iliac artery occlusion without the need for subsequent amputation or major disability included extraanatomic bypass in 7 patients, PTA (3 patients) and implantation of wallstents (2 patients) or conservative management (1 patient).     

Bacteriuria and colonization of double-pigtail ureteral stents: long-term experience with 237 patients

We prospectively studied 266 patients with indwelling double-pigtail ureteral stents to determine the incidence of stent colonization and associated bacteriuria. A urine culture was obtained just prior to stent insertion and was repeated at the time of its removal. The stent itself was also cultured. Of the 237 evaluable patients, 71 (29.9%) developed bacteriuria. Of the 237 stents, 161 (67.9%) became colonized with microorganisms. Pseudomonas aeruginosa was the most common pathogen isolated from the urine and the stents. Stents in female patients had a higher rate of colonization than those used in males (74.4% v 66.5%). The longer the duration of stenting, the higher was the rate of colonization (58.6% for stents left for < 1 month v 75.1% for those left for > 3 months). The rate of colonization according to catheter type was as follows: C-flex 55.5%, silicone 62.6%, urethane 100%, and Urosoft 56%. Long-term ureteric stenting is associated with a high rate of bacteriuria and stent colonization. The duration of stenting and the type of stent influence the results. We recommend that patients with double-J ureteral stents who could be at risk from bacteremia be covered by appropriate antibiotics, and the stents should be kept indwelling for the shortest possible time. If a patient with a stent develops symptomatic infection, an antibiotic should be started that covers the Pseudomonas species.     

A new design of the esophageal Wallstent endoprosthesis resistant to distal migration

OBJECTIVE: Because plastic-covered metallic stents used in the palliation of patients with unresectable esophageal cancer are associated with significant rates of migration, particularly when the lower end of the stent projects into the gastric fundus, the purpose of this study was to establish whether two new prototype designs of the Wallstent esophageal endoprosthesis are prone to migration. SUBJECTS AND METHODS: A cylindrical stent and a conical stent were studied. Both designs included plastic covering inside the metallic mesh. In addition, the conical device incorporated a variation in the braiding angle between the upper and lower parts of the endoprosthesis. Ten conical stents and eight cylindrical stents were inserted in 18 patients with tumors involving the gastroesophageal junction who were followed up with esophagography and endoscopy. RESULTS: All insertions of stents were successful. Two cylindrical stents (25%) migrated distally. Two conical stents (20%) migrated proximally. One perforation occurred that was associated with distal migration of a cylindrical stent. CONCLUSION: The frequency of distal migration of cylindrical stents is unacceptably high. Conical stents are resistant to distal migration, although improvements in design are required to deal with the problem of proximal migration.