Transjugular intrahepatic portosystemic shunting (TIPS) with balloon-expandable and self-expanding stents: Technical and clinical aspects after 3 1/2 years’ experience

Purpose To evaluate prospectively our experience with transjugular intrahepatic portosystemic shunt (TIPS) using four different metallic stents. Methods Between November 1991 and April 1995, 57 patients (41 men and 16 women; age 35–72 years, mean 54 years) underwent the TIPS procedure. Techniques for portal vein localization before and during TIPS were fluoroscopy, computed tomography (CT) studies, wedged hepatic venography, arterial portography, and ultrasound. After predilation we deployed balloon-expandable (n=48) and self-expanding (n=45) metallic stents. Fifteen patients underwent variceal embolization. Initial follow-up angiograms (mean 6.9 months, range 3–24 months) were obtained in 39 of these patients. Results Fifty-three patients (93%) had successful TIPS placement. The mean decrease in portal pressure was 42.7%. Besides fluoroscopy, the most helpful techniques for portal vein localization were venography and CT. Residual stenosis (n=1) and late shortening (n=4) of Wallstents resulted in shunt dysfunction. The technical problems encountered with the Palmaz stent resulted from its lack of flexibility. We combined balloon-expandable and self-expanding stents in 12 patients. The 30-day and late follow-up (mean 11.9 months) percutaneous reintervention rates were 11.3% and 64.2%, respectively. There were no clinically significant complications related to the TIPS insertions. Conclusion An ideal stent does not exist for TIPS, and the authors recommend combining a Palmaz stent with a flexible self-expanding stent.     

Transjugular intrahepatic portosystemic shunts with Spiral Z stents: first clinical experience in 20 patients

We report our preliminary experience with Spiral Z stents for transjugular intrahepatic portosystemic shunts (TIPS). The Spiral Z stent is a modification of the Gianturco-Rosch stent. TIPS was performed in 20 patients with symptomatic portal hypertension and was effective in 19 of them. One patient re-bled and died shortly after the procedure, despite of transjugular embolisation of gastro-oesophageal varices. The portal pressure decrease (5–16 mm Hg) was related to stent diameter (8–12 mm). Mean follow-up was 6 months. Our preliminary results confirm that the 12-mm Spiral Z stent is a suitable device for creation of effective TIPS. Correspondence to: A. Krajina     

Is the tantalum Strecker stent suitable for TIPS creation? short- and mid-term results in 20 consecutive patients

Purpose To assess the suitability of tantalum Strecker stents for transjugular intrahepatic portosystemic shunt (TIPS) creation. Methods TIPS was performed with Strecker balloon-expandable stents in the first 20 patients of our series. A total of 26 prostheses were utilized (average 1.3 per patient). Results Immediate technical success was achieved in all 20 cases. Nine patients (45%) died during follow-up. The overall average follow-up period was 18.9 months; the 11 survivors were followed for a mean period of 29.8 months. In 4 patients (20%) the stent dislodged towards the hepatic vein during withdrawal of the balloon catheter, and difficulties in recatheterizing the shunt for routine control portal phlebography were frequently encountered. Rebleeding occurred in 5 cases and aggravation of pre-existing encephalopathy occurred in 2 cases. Shunt occlusions or stenosis required further intervention in 4 and 9 patients, respectively. Conclusion In our opinion the tantalum Strecker stent is not particularly suitable for TIPS. Although it has evident advantages, such as high radiopacity and minimal shortening after deployment, the tendency of the device to dislodge and the difficulty in recatheterization during portal phlebography were important drawbacks. Furthermore, the atraumatic ends of the device did not seem to reduce shunt-related complications, which were comparable to those occurring with other types of stent.     

Self-expanding nitinol stents for treatment of infragenicular arteries following unsuccessful balloon angioplasty

The feasibility of self-expanding nitinol stents for treatment of infragenicular arteries following unsuccessful balloon angioplasty was assessed. Options for lower limb percutaneous revascularization are limited, especially for complex vessel obstruction. Depending on the lesion and the experience of the interventionalist, the failure rate of balloon angioplasty (PTA) ranges between 10 and 40%. Until recently, no self-expanding stent for the use in the infragenicular arteries was available. This is the first report of the results for 18 consecutive patients who received 4F sheath compatible self-expanding nitinol stents following unsuccessful PTA or early restenosis. Twenty-four stents were implanted in 21 lesions for various indications residual stenosis >50% due to heavy calcification, flow-limiting dissection, occluding thrombus resistant to thrombolyis, thrombaspiration, and PTA, and early restenosis after previous PTA. Stent implantation was feasible in all cases. No complications occurred. After the stent implantation, all primarily unsuccessful interventions could be transformed into successful procedures with no residual stenosis >30% in any case. After 6 ± 2 months, two of the 18 patients died, and 14 of the 16 remaining patients improved clinically. At follow-up, the patency could be assessed in 14 stented arteries. Three stents were occluded, one stent showed some neointimal hyperplasia (50–70% restenosis), the remaining ten stents showed no restenosis (0–30%). The use of self-expanding nitinol stents in tibioperoneal and popliteal arteries is a safe and feasible option for the treatment of unsuccessful PTA. The 6-months patency is high.     

Treatment of malignant dysphagia with nitinol stents

Self-expanding nitinol stents were used in 22 patients for palliative treatment of malignant esophagogastric strictures. All patients but 5 were men (age range 47–75 years). The strictures were caused by squamous cell carcinoma (n = 12), adenocarcinoma (n = 8), and recurrent anastomotic carcinoma (n = 2). No technical failure or procedural complications occurred. After the procedure, the severity of dysphagia decreased at least one grade in all patients. Tumor ingrowth into the stent was seen in 7 patients of 22 (32%). Four of these patients were treated with additional stents, and in 3 patients, due to refusal, only balloon dilations were performed, which caused temporary relief. Tumor ingrowth into the stent was noted from 10 days to 7 months (mean 3 months). This seems to be a disadvantage of nitinol stents. At the end of the study 10 patients had died dead with a mean survival of 3 months (range 1 week to 6 months) and 12 patients were still alive with a mean follow-up of 4 months (range 1–8 months). It is concluded that nitinol stents provide satisfactory palliation in patients with malignant dysphagia with neglectable procedural morbidity and mortality rates.     

A new nitinol monofilament stent: early experience with use for transjugular intrahepatic portosystemic shunts

The purpose of this study was to investigate the suitability of a new nitinol monofilament stent (Niti-S) for transjugular intrahepatic portosystemic shunt (TIPS) creation. TIPS was performed with a Niti-S stent in 22 patients for variceal bleeding (n = 20) or intractable ascites (n = 2). The efficacy, complication, and patency rates during the follow-up period (up to 27 months, mean 13.9 months) were evaluated. TIPS was successfully performed in all patients. The mean portosystemic pressure gradient decreased from 23.8 ± 7.2 mmHg to 10.2 ± 3.1 mmHg. No mortality or significant morbidity was encountered at 1 month. Variceal bleeding and/or ascites were controlled in all patients. Primary patency rates were 77.3% at 6 months and 71.8% at 1 year. Secondary patency rates were 95.4% up to 26 months. TIPS with the Niti-S stent produced short-term technical and clinical results comparable to the other commercially available stents. A prospective randomized comparison study is indicated.     

Elastic deformation properties of implanted endobronchial wire stents in benign and malignant bronchial disease: A radiographic in vivo evaluation

PURPOSE: To evaluate the long-term mechanical behavior in vivo of expandable endobronchial wire stents, we imaged three different prostheses in the treatment of tracheobronchial disease. METHODS: Six patients with bronchial stenoses (three benign, three malignant) underwent insertion of metallic stents. Two self-expandable Wallstents, two balloon-expandable tantalum Strecker stents and two self-expandable nitinol Accuflex stents were used. Measurements of deformation properties were performed during voluntary cough by means of fluoroscopy, at 1 month and 7-10 months after implantation. The procedures were videotaped, their images digitized and the narrowing of stent diameters calculated at intervals of 20 msec. RESULTS: After stent implantation all patients improved with respect to ventilatory function. Radial stent narrowing during cough reached 53% (Wallstent), 59% (tantalum Strecker stent), and 52% (nitinol Accuflex stent) of the relaxed post-implantation diameter. Stent compression was more marked in benign compared with malignant stenoses. In the long term permanent deformation occurred with the tantalum Strecker stents; the other stents were unchanged. CONCLUSION: Endobronchial wire stents can be helpful in the treatment of major airway collapse and obstructing bronchial lesions. However, evidence of material fatigue as a possible effect of exposure to recurrent mechanical stress on the flexible mesh tube may limit their long-term use. This seems to be predominantly important in benign bronchial collapse.     

Preliminary results of a new expanded-polytetrafluoroethylene-covered stent-graft for transjugular intrahepatic portosystemic shunt procedures.

OBJECTIVE: The purpose of our study was to evaluate the feasibility and the safety of transjugular intrahepatic portosystemic shunts (TIPS) with a new expanded-polytetrafluoroethylene-covered stent and the influence of the covering on occlusion rate. SUBJECTS AND METHODS: Twenty cirrhotic patients (57 +/- 11 years old) admitted with a history of esophageal variceal bleeding (n = 11), refractory ascites (n = 5), or both (n = 4) were included. Five of the patients were treated for TIPS revision, and 15 as de novo TIPS placements. The endoprostheses used were composed of a 2-cm noncovered nitinol stent and a 4- to 8-cm expanded-polytetrafluoroethylene graft covering, and were placed from the portal vein to the ostium of the hepatic vein. Patients underwent Doppler sonography at discharge and again at 1, 3, 6, 9, 12, and 15 months and underwent venography with portosystemic pressure gradient measurement at 6 months and whenever necessary. RESULTS: At the time of this writing, complications included three TIPS restenoses and one recurrent ascites successfully treated by balloon dilation, two cases of segmentary liver ischemia, and one patient with encephalopathy that required shunt reduction. After TIPS placement, the portosystemic pressure gradient dropped from 18 +/- 5 to 5 +/- 4 mm Hg. Primary and secondary patency rates were 80% and 100%, respectively, at 387 days. CONCLUSION: These results clearly show the feasibility of TIPS placement with the Gore TIPS endoprosthesis stent-graft and its improved patency compared with results in the literature for bare stents. These preliminary results must be certified further with randomized comparative trials between covered and noncovered TIPS stents.     

Primary patency of femoropopliteal arteries treated with nitinol versus stainless steel self-expanding stents: propensity score-adjusted analysis

PURPOSE: To evaluate, in a propensity score-adjusted analysis, the intermediate-term primary patency rates associated with nitinol versus stainless steel self-expanding stent placement for treatment of atherosclerotic lesions in femoropopliteal arteries. MATERIALS AND METHODS: The authors analyzed the clinical and imaging data of 175 consecutive patients with peripheral artery disease and either intermittent claudication (n = 150) or critical limb ischemia (n = 25) who underwent femoropopliteal artery implantation of nitinol (n = 104) or stainless steel (n = 123) stents in a nonrandomized setting. The stents were placed owing to either significant residual stenosis (ie, >30% lumen diameter reduction) or flow-limiting dissection after initial balloon angioplasty of the femoropopliteal artery. Patients were followed up for a median period of 9 months (mean, 13 months; range, 6-66 months) for the detection of a first in-stent restenosis, defined as a greater than 50% lumen diameter reduction that was seen at color-coded duplex ultrasonography and confirmed at angiography. RESULTS: Cumulative patency rates at 6, 12, and 24 months were 85%, 75%, and 69%, respectively, after nitinol stent placement versus 78%, 54%, and 34%, respectively, after stainless steel stent placement (P =.008, log-rank test). There were no statistically significant differences in associated patency among the three different nitinol stents used (P =.72, log-rank test). Multivariate Cox proportional hazard analysis, in which the effect of propensity to receive a nitinol stent was considered, revealed a significantly reduced risk of restenosis with the nitinol stents compared with the risk of restenosis with the stainless steel stents (adjusted hazard ratio, 0.44; 95% confidence interval: 0.22, 0.85; P =.014). CONCLUSION: Nitinol stents are associated with significantly improved primary patency rates in femoropopliteal arteries compared with stainless steel stents. Randomized controlled trials are needed to confirm these results.     

Transjugular intrahepatic portosystemic shunt in the treatment of portal hypertension using memotherm stents: a prospective multicenter study

Purpose: In a prospective multicenter study, efficacy and safety of transjugular intrahepatic portosystemic shunts (TIPS) were evaluated in the treatment of the complications of portal hypertension using a new self-expanding mesh-wire stent (Memotherm). Methods: One hundred and eighty-one patients suffering from variceal bleeding (either acute or recurrent) or refractory ascites were enrolled. Postinterventional follow-up lasted for 8.4 months on average. Differences were analyzed by the log-rank test (chi-square) or Wilcoxon test. Results: Shunt insertion was completed successfully in all patients (n = 181 patients, 100%). During follow-up, shunt occlusion was evident in 23 patients, and shunt stenosis was found in 33 patients (12.7% and 18.2%, respectively). Variceal rebleeding occurred in 20 of 139 patients (14.4%), with at least one episode of bleeding before TIPS treatment. The overall mortality rate of the patients treated by TIPS was 39.8%. In 51.4% of these cases (37 of 72 patients), however, the patients died within 30 days after TIPS placement. Analysis of subgroups showed that patients who underwent emergency TIPS for acute variceal bleeding had a significantly higher early mortality compared with other patient groups (p = 0.0014). Conclusion: In the present prospective multicenter study, we were able to show that insertion of Memotherm stents is an effective tool for TIPS. The occlusion rates seem to be comparable to those reported for the Palmaz stent. It could be shown that in particular, those patients who were treated for acute bleeding were at high risk of early mortality. Consequently, in such a critical condition, the indication for TIPS has to be set carefully.     

Flexible tantalum stents: Effects in the stenotic canine urethra

Purpose Evaluate the effects of flexible tantalum stents (Strecker) implanted into stenotic canine urethras.Methods Eight conditioned, adult, German shepherd dogs, weighing 30–40 kg, were used. Strictures were created surgically in the bulbar urethra just proximal to the os penis. Two months postsurgery, strictures were documented radiographically and then balloon dilated. Following dilatation, a single Strecker stent was placed across the stricture. Stents were 7 mm in expanded diameter and either 2 or 4 cm in length. Retrograde urethrography was performed immediately after stent placement and then biweekly for up to 12 months. Two dogs were sacrificed at 2, 4, 6, and 12 months post-stenting, and necropsy was performed. The urethra was excised, fixed, and examined by scanning electron and light microscopy.Results Clinical success was achieved without complications in all animals. Hyperplasia of the urothelium was noted 4–6 weeks after stent placement and was most pronounced at 4–6 months. Mucosal folds were found between the stent struts. Restenosis occurred at the distal end of the stent in one dog. Histological alterations were noted in the deeper layers of the urethral wall.Conclusion Strecker stents were well tolerated in all animals and seem useful for the treatment of urethral strictures.Presented at CIRSE Annual Meeting and Postgraduate Course, Budapest, June 20–24, 1993     

Endovascular placement of self-expanding nitinol coil stents for the treatment of femoropopliteal obstructive disease

PURPOSE: To report on a prospective two-center study to evaluate safety and effectiveness of a self-expanding nitinol coil stent in patients with femoropopliteal obstructive disease. MATERIALS AND METHODS: The IntraCoil nitinol stent was used in 37 patients (28 men and nine women; mean age, 62.4 y plus minus 10.7; range, 43-81 y) presenting with high-grade stenoses (n = 23) or short (<3 cm) occlusions (n = 17) of the superficial femoral artery (SFA; n = 33) or popliteal artery (n = 4). Indications for stent placement were significant residual stenosis (>30%) or dissection after angioplasty. Follow-up evaluations with measurement of the Doppler ankle-brachial index (ABI), assessment of Rutherford clinical stage, and color-coded duplex sonography were performed at discharge and 1, 3, 6, 12, and 18 months thereafter. Primary endpoints of the study were immediate technical and clinical success and 1-year patency. RESULTS: Initial technical success was achieved in all patients. In 10 patients (27%), more than one 40-mm-long device had to be implanted for total lesion coverage; in three patients (8.1%), stents were placed in two separate segments of the SFA simultaneously. The total number of stents deployed was 50. Stent placement induced an initial improvement of the ABI from 0.54 plus minus 0.2 to 0.92 plus minus 0.11 (P <.01). Follow-up data for 12 months after treatment are available for 29 of 37 patients (78.4%); mean follow-up is 15.6 months (range, 1-26 mo). Primary patency rates at 6 and 12 months were 97.1% (SE = 2.9) and 86.2% (SE = 6.5). The primary assisted patency rate was 100% at 12 months. CONCLUSION: Endovascular placement of the IntraCoil self-expanding nitinol coil stent for salvage of failed angioplasty in patients with femoropopliteal obstructive disease is an effective and safe procedure with promising mid-term results.     

Elastic Deformation Properties of Implanted Endobronchial Wire Stents in Benign and Malignant Bronchial Disease: A Radiographic In Vivo Evaluation

Purpose: To evaluate the long-term mechanical behavior in vivo of expandable endobronchial wire stents, we imaged three different prostheses in the treatment of tracheobronchial disease. Methods: Six patients with bronchial stenoses (three benign, three malignant) underwent insertion of metallic stents. Two self-expandable Wallstents, two balloon-expandable tantalum Strecker stents and two self-expandable nitinol Accuflex stents were used. Measurements of deformation properties were performed during voluntary cough by means of fluoroscopy, at 1 month and 7–10 months after implantation. The procedures were videotaped, their images digitized and the narrowing of stent diameters calculated at intervals of 20 msec. Results: After stent implantation all patients improved with respect to ventilatory function. Radial stent narrowing during cough reached 53% (Wallstent), 59% (tantalum Strecker stent), and 52% (nitinol Accuflex stent) of the relaxed post-implantation diameter. Stent compression was more marked in benign compared with malignant stenoses. In the long term permanent deformation occurred with the tantalum Strecker stents; the other stents were unchanged. Conclusion: Endobronchial wire stents can be helpful in the treatment of major airway collapse and obstructing bronchial lesions. However, evidence of material fatigue as a possible effect of exposure to recurrent mechanical stress on the flexible mesh tube may limit their long-term use. This seems to be predominantly important in benign bronchial collapse.     

Treatment of Benign Tracheal Stenosis Utilizing Self-Expanding Nitinol Stents

We assessed the results of self-expanding metallic stent insertion into benign proximal tracheal stenosis in patients not appropriate or unfit for surgical repair. Proximal benign tracheal stenoses had occurred in 11 patients (7 men, 4 women, mean age 68.8 years) after long-time intubation (n = 6), tracheostomy (n = 4), or chondropathia (n = 1). Fourteen self-expanding nitinol stents were placed in the patients under general anesthesia with endoscopical and fluoroscopical guidance. Stent insertion was successful in all cases and led to immediate relief of the morphological and functional airway obstruction. No immediate complications were noted. During the mean follow-up period of 67.5 weeks we observed one recurrent dyspnea 3 months after implantation and granuloma formation at the stent insertion site in another patient. Both complications were successfully treated with additional stent insertion in one case and laser resection of granulomas in the other. Self-expanding nitinol stents should be considered for the treatment of benign proximal tracheal obstruction in selected patients for whom surgical repair is contraindicated.     

Self-expanding nitinol stents in the femoropopliteal segment: technique and mid-term results

The purpose of this study was to evaluate the safety and efficacy of self-expanding SMART nitinol stents in patients with chronic limb ischemia (CLI) demonstrating Type B or C TransAtlantic Inter-Society Consensus (TASC) lesions in the femoropopliteal (FP) arterial segment. There were 137 lower limbs in 122 patients with chronic limb ischemia, secondary to TASC A (n = 12) or TASC B,C (n = 125) lesions in the FP artery were treated with Cordis SMART self-expanding nitinol stents. Hemodynamic stent failure occurred with the presence of a greater than 50% stenosis within the stented segment, measured by standard Duplex velocity criteria, obtained at various postintervention intervals. The hemodynamic primary stent patency was calculated by life-table methods from the time of intervention, uninterrupted by hemodynamic stent failure. The mean lesion length was 12.2 cm (range, 4 to 28 cm). The technical success was 98%. Within the follow-up period (mean, 302 days), 24 limbs were diagnosed with hemodynamic stent failure. The hemodynamic primary stent patency rates were 92%, 76%, 66%, and 60% at 6, 12, 18, and 24-months, respectively. These data provide objective evidence that endovascular treatment of FP TASC A, B and C lesions using self-expanding nitinol SMART stents in patients with chronic limb ischemia provides favorable safety and durability outcomes. Further investigation is warranted.     

Palliative treatment of neoplastic strictures by self-expanding nitinol Strecker stent

The purpose of this study was to evaluate technical and clinical results of self-expanding esophageal stent implanted in patients with malignant esophageal strictures and clinically significant dysphagia. From June 1992 to September 1994, 27 patients with inoperable tumors of the esophagus or gastric cardiac were treated by placement of 37 self-expanding nitinol stents. Water-soluble contrast and endoscopy studies were performed after the procedure and during the follow-up period. Successful stenting of the stricture was achieved in 27 patients. The mean dysphagia grade dropped from 2.3 to 1 (SD ± 0.54) immediately after the procedure. After the insertion of the stent, 16 patients died in a period of time ranging from 0 to 13 months (mean 5.6 months), whereas at the end of the study 11 patients were alive 4–15 months after the procedure (mean 8.3 months). No major complications were observed. The results of this study are encouraging because esophageal stent placement was technically easy and clinically effective. Correspondence to: F. Maspes     

Puncture of stents implanted into veins and arteriovenous fistulas: An Experimental Study

Purpose Puncture of venous Wallstents and nitinol stents with dialysis needles was tested in an animal study.Methods In 15 sheep, divided into a group with prior surgical unilateral carotid-jugular shunt creation (9 sheep) and a second group without shunt creation (6 sheep), a self-expanding nitinol stent and/or a Wallstent were bilaterally placed into the jugular veins. After 1 month, 10 nitinol stents and 9 Wallstents were punctured weekly with a 15-gauge cannula over a period of 15 weeks. Stent patency was followed up by colorcoded duplex ultrasound and angiography. After sacrifice, high resolution X-rays of the removed vessels were taken to assess stent deformation. From histological slices, neointimal thickness inside the stents was measured and analyzed statistically.Results Puncturing of both the nitinol stent and the Wallstent was technically feasible. Stent deformations were not found. One stent stenosis, probably related to puncture, was observed. The pattern of intimal hyperplasia differed between the nitinol stent and the Wallstent. Outward bulge of the vascular layers over the stent struts was greater in nitinol stents. In the relevant area in between the stent struts there was no significant difference in intimal thickness between the two types of stents. Intimal thickness was more pronounced in shunted than in nonshunted animals only in the Wallstent subgroup (p = 0.025) and more pronounced in punctured than in nonpunctured stents only in the nitinol stent subgroup (p = 0.018).Conclusion Puncturing of stents was feasible without major short-term complications. Therefore, stent implantation into the punctured segment of a hemodialysis fistula may be indicated if there is no alternative treatment.     

Oversizing of self-expanding stents: influence on the development of neointimal hyperplasia of the carotid artery in a canine model

BACKGROUND AND PURPOSE: In carotid artery stent placement, marked oversizing of the stent relative to the internal carotid artery lumen is common. This study was performed to determine the influence of using oversized self-expanding nitinol stents on neointimal hyperplasia. METHODS: In six greyhound dogs, 24 self-expanding nitinol stents (eight SMART stents, eight Easy Wallstents, eight Sinus-Flex stents) were inserted into both common carotid arteries (CCAs). In each CCA, two stents were deployed; a stent of the appropriate diameter was implanted distally and an oversized stent proximally. After 4 months, transverse sections of each stent were examined histologically and at computerized image analysis. Neointimal hyperplasia was determined as the proportion of the residual diameter of the patent vessel lumen compared with the stent lumen. RESULTS: The amount of neointimal hyperplasia did not differ between the normal-sized and oversized stents. The mean preserved luminal diameter (+/-SEM) with normal- and oversized stents, respectively, were as follows: Easy Wallstent, 94% +/- 1.0 and 96% +/- 1.5; SMART stent, 92% +/- 1.6 and 93% +/- 1.8; and Sinus-Flex stent, 93% +/- 2.7 and 93% +/- 2.6. The mean preserved patent lumen with the 12 normal-sized stents (93% +/-1.0) was not significantly different from that of the 12 oversized stents (94% +/- 1.1, P =.502). CONCLUSION: Under experimental conditions, use of self-expanding stents oversized by 30-40% appeared to result in neointimal hyperplasia comparable to that caused by normal-sized stents. All three stent types appeared to have similarly low neointimal responses.     

Metallic stents for treatment of benign biliary obstruction: a long-term study comparing different stents

PURPOSE: To investigate the role of metallic stents in the treatment of benign biliary strictures and analyze the differences in primary patency associated with the various types of stents deployed. MATERIALS AND METHODS: Between 1990 and 1997, 21 patients with benign obstructive jaundice were treated with transhepatic placement of metallic stents (11 Wallstents in 10 patients, nine Palmaz stents in seven patients, and four tantalum Strecker stents in four patients). Nineteen patients presented with strictures not responding to balloon angioplasty (postsurgical, n = 13; cholangitis, n = 5; unknown, n = 1). Estimates for cumulative patency, patency rate in the different stent groups, and survival were calculated with use of life-table analysis; the log-rank test was used to compare the different stent groups. The prognostic relevance of the selected variables-stent type, stent length, etiology, and location-were modeled with respect to patency according to Weibull distribution. RESULTS: The median follow-up time was 80.5 months (range, 2-116 months). The median survival time was 91 months. One patient was lost to follow-up after 3 months. Repeat intervention for recurrent obstructive jaundice was necessary in 11 patients (55%), and the median patency rate was 26 months (range, 2-96 months). The Palmaz stent was the most effective in achieving long-term patency, with a median patency duration of 36 months (range, 22-96 months), versus 9 months (range, 3-67 months) for the Wallstent and 6 months (range, 2-15 months) for the tantalum Strecker stent. The cumulative patency rate with the Palmaz stent was significantly higher than for the tantalum Strecker stent (log-rank test, P = .017) and nonsignificantly higher compared with the Wallstent (log-rank test, P = .07). Multivariate analysis showed that the type of stent (Wald test, P = .003) and stent length (Wald test, P < .0001) influenced the patency rate. CONCLUSIONS: These results suggest that the type of stent and the stent length have a significant influence on the patency rate. In this series, the Palmaz stent was most effective in achieving long-term patency in benign biliary strictures.     

Percutaneous self-expandable uncovered metallic stents in malignant biliary obstruction. Complications,follow-up and reintervention in 154 patients

Purpose:
Evaluation of technique, complications and the long-term follow-up data of 154 patients with inoperable malignant biliary obstruction who underwent percutaneous placement of metallic stents. Material and Methods:
During a 6-year period, 224 self-expanding metallic stents (150 biliary Wallstents and 74 Memotherm nitinol stents) were inserted in 154 patients with inoperable malignant biliary obstruction. 100 patients had obstructions at the proximal (supracystic) level, and 54 at the distal (infracystic) level. The causes of obstructions were hilar cholangiocarcinoma (n = 64), pancreatic carcinoma (n = 34), gallbladder carcinoma (n = 24), metastatic carcinoma (n = 21), common bile duct carcinoma (n = 8), and hepatocellular carcinoma (n = 3). A complete follow-up was available for all patients. Results:
The 30-day mortality was 9%, with no procedure-related deaths. The clinical success rate within the first 30 days was 88%. The total rate of early, procedure-related complications was 28%, and half of them were due to the percutaneous transhepatic catheter drainage procedure. Recurrent jaundice occurred in 28 (18%) patients and in 23 (82%) of these, reinterventions were made in order to relieve reobstructions. The mean length of survival for the entire patient group was 4 months, while the mean period of patency for all stents was 6 months. We found no statistically significant difference in patient survival or stent patency periods in regard to the level and cause of obstruction. Conclusion:
Percutaneous metallic stent placement maintains equal palliation in patients with proximal and distal malignant biliary obstructions caused by any tumor type. Most of the early complications were due to procedures performed before stent insertion and could be decreased by direct stent insertions. The most common late complication, reobstruction, is inevitable but can be easily treated in the majority of patients.