Transjugular intrahepatic portosystemic shunts formed with polyethylene terephthalate-covered stents: experimental evaluation in pigs

PURPOSE: To evaluate the safety, efficacy, and tissue response associated with Wallstents covered with polyethylene terephthalate (PETP) compared with those associated with uncovered Wallstents for creation of transjugular intrahepatic portosystemic shunts (TIPS) in a porcine model. MATERIALS AND METHODS: Thirteen TIPS were created in 13 minipigs: eight with PETP-covered Wallstents, five with standard Wallstents. Shunt venography was performed at 5-8 weeks, and necropsy was performed at 7-8 weeks. Histopathologic, immunohistochemical, and scanning electron microscopic examinations were performed. RESULTS: Mean shunt stenoses of the control and graft groups were 45% and 53%, respectively. Graft stenoses involved the entire graft-bearing segment, whereas bare stent stenoses were localized within the liver tract. Myofibroblast and extracellular collagen matrix proliferation encompassed both control and graft-covered stents. There was one graft TIPS occlusion. One control TIPS stenosis was due to transstent proliferation of normal porcine hepatic tissue. A small focus of bile staining was seen on the abluminal surface of one TIPS, which was a patent PETP-lined shunt. CONCLUSION: PETP graft TIPS provided equal, but not superior, patency to that of bare stent TIPS. The pattern of PETP TIPS graft healing differed from that of bare stents but was similar to that reported with other polyester graft vascular implants and consisted of diffuse transmural penetration and paving of the graft surface by extracellular collagen matrix and myofibroblasts.     

Pull-Through Technique for Recanalization of Occluded Portosystemic Shunts (TIPS): Technical Note and Review of the Literature

Transjugular intrahepatic portosystemic shunt (TIPS) dysfunction is an important problem after creation of shunts. Most commonly, TIPS recanalization is performed via the jugular vein approach. Occasionally it is difficult to cross the occlusion. We describe a hybrid technique for TIPS revision via a direct transhepatic access combined with a transjugular approach. In two cases, bare metal stents or polytetrafluoroethylene (PTFE)-covered stent grafts had been placed in TIPS tract previously, and they were completely obstructed. The tracts were inaccessible via the jugular vein route alone. In each case, after fluoroscopy or computed tomography-guided transhepatic puncture of the stented segment of the TIPS, a wire was threaded through the shunt and snared into the right jugular vein. The TIPS was revised by balloon angioplasty and additional in-stent placement of PTFE-covered stent grafts. The patients were discharged without any complications. Doppler sonography 6 weeks after TIPS revision confirmed patency in the TIPS tract and the disappearance of ascites. We conclude that this technique is feasible and useful, even in patients with previous PTFE-covered stent graft placement.     

Improved patency of transjugular intrahepatic portosystemic shunts in humans: creation and revision with PTFE stent-grafts

PURPOSE: To determine whether polytetrafluoroethylene (PTFE) stent-grafts yield longer patency for creation or revision of transjugular intrahepatic portosystemic shunts (TIPS). MATERIALS AND METHODS: Fourteen PTFE-covered Wallstents were placed in 13 patients with TIPS: seven at shunt creation and seven during revision of TIPS with one to five prior thromboses at 1 day to 1 year after initial TIPS formation. In six cases, prior to stent-graft placement persistent biliary-TIPS fistulas were demonstrated despite repeated shunt revisions with additional metallic stents. RESULTS: All but one graft-lined TIPS were widely patent at a mean duration of venographic follow-up of 19 months (median, 17 months; range, 5-32 months). The limiting percentage of stenosis within the grafted shunts was 0%-10%. One patient developed stent-graft thrombosis; the prior biliary-TIPS fistula was seen despite the graft. A second, parallel PTFE-lined transcaval shunt was created in this patient; it was widely patent at 11-month follow-up. In two asymptomatic patients, stenoses developed in the short, nongrafted portions of the outflow hepatic veins. CONCLUSION: PTFE stent-grafts can markedly prolong TIPS patency, potentially reducing the need for shunt follow-up and revision and the risk of recurrent symptoms associated with shunt stenosis or occlusion.     

Combined transhepatic and transjugular approach for mechanical thrombectomy of massive TIPS thrombosis

Transjugular intrahepatic portosystemic shunt (TIPS) is a well-validated decompressive therapy option to manage ascites and variceal bleeding secondary to portal hypertension. Complications following TIPS procedures include hepatic encephalopathy, liver failure, and TIPS dysfunction. TIPS dysfunction is due to occlusion or stenosis of the TIPS shunt and can be caused by acute or chronic thrombosis. TIPS thrombosis is often treated with mechanical thrombectomy or catheter-directed thrombolytic therapy. Most cases of in-stent occlusion can be treated via a transjugular approach with recanalization or placement of additional stents. We present a case of a 72-year-old female who presented with worsening ascites 17 months after initial TIPS procedure; she was found to have a large thrombus completely occluding the TIPS stent. In our case, a combined transhepatic and transjugular approach was required for TIPS revision given the extent of well-organized clot located near the hepatic venous end of the stent, resulting from prolonged stent occlusion. This was an extremely challenging scenario with two overlapping covered stents and a bare metal stent at the hepatic venous end in the setting of chronic thrombosis and a well-organized fibrous cap. The case highlights the need for optimal initial placement of the primary TIPS shunt to avoid the need for subsequent complex interventions to maintain TIPS shunt patency.     

The use of a polytetrafluoroethylene-covered stent graft for transjugular intrahepatic portosystemic shunt (TIPS): Long-term follow-up of 100 patients

PURPOSE: To retrospectively evaluate results and clinical outcome of transjugular intrahepatic portosystemic shunt (TIPS) after implantation of a polytetrafluoroethylene (PTFE)-covered stent graft. MATERIAL AND METHODS: The stent graft was used in 112 patients with higher risk of primary (i.e. patients with Budd-Chiari syndrome) or secondary shunt failure (patients with occlusion of a previous uncovered stent), or a complicated TIPS procedure with an imminent technical complication requiring covered stent. Patients were scheduled at 3- to 6-month intervals for duplex-sonographic control of shunt function. Radiological revision was performed in patients with a decrease in shunt function by >25%, primary non-response, or relapse of the index symptom. RESULTS: Twelve patients were lost to follow-up, and 100 patients were followed for 22+/-15 months. The actuarial rates of shunt patency were 90, 84, and 74% at 1, 2, and 3 years of follow-up, respectively. Two patients developed early (within 1 month) and 14 patients late shunt failure. Except for one transient rise in liver enzymes due to outflow obstruction by the stent graft, no technical complications were seen. Primary response to treatment was seen in 97% of patients treated for variceal bleeding and 84% of patients treated for refractory ascites. A relapse of the index symptom was seen in 13% of bleeders and 9% of patients treated for refractory ascites. CONCLUSION: TIPS created with a PTFE-covered stent graft showed favorable long-term results.     

Use of balloon-expandable stents in transjugular intrahepatic portosystemic shunts in cases of Wallstent endoprosthesis technical failure and revision of shunt stenosis

Thirteen patients underwent placement of a balloon-expandable stent either at initial transjugular intrahepatic portosystemic shunt (TIPS) creation (n = 3) because of immediate technical failure of the Wallstent or at shunt revision because of failure of the Wallstent to reduce the portosystemic gradient 相似文献   

Transjugular intrahepatic portosystemic shunt patency and clinical outcome in patients with Budd-Chiari syndrome: covered versus uncovered stents

PURPOSE: To retrospectively compare primary patency and reintervention rates, clinical outcome, and improvement in hepatic dysfunction (Child-Pugh score) in patients with Budd-Chiari syndrome treated with transjugular intrahepatic portosystemic shunt (TIPS) using bare stents or expanded polytetrafluoroethylene (PTFE)-covered stents. MATERIALS AND METHODS: Approval of study and treatment protocol and waiver of informed consent for the retrospective study were obtained from institutional review board. Informed consent was obtained from each patient before procedure. Four male and nine female consecutive patients (mean age, 35.7 years) with Budd-Chiari syndrome treated with TIPS from January 1994 to November 2003 were included. In six patients, TIPS creation was performed with bare stents (group A). After April 2001, TIPS creation was performed in seven patients with expanded PTFE-covered stent-grafts (group B). Follow-up (group A mean, 22.7 months +/- 10.53 [standard deviation]; group B mean, 23.1 months +/- 7.81) was performed at 7 days, 30 days, and 3 months and subsequently every 3 months. Liver function was evaluated every 3 months. Primary end points were 6- and 12-month TIPS patency rates. Secondary end points were reintervention rate and clinical outcome. Patency rates were estimated (Kaplan-Meier method) and compared (log-rank test). Continuous (Mann-Whitney U test) and categoric (chi(2) test) data were compared. Significant differences before and after treatment were determined (Wilcoxon test). RESULTS: Mean primary patency duration was 4.46 months +/- 3.40 in group A and 22.29 months +/- 8.15 in group B. In group B, a significant increase in primary patency rate (100% and 85.7% vs 16.7% and 0% at 6 and 12 months; P < .001, log-rank test) and a decrease in reintervention rate (0.29 +/- 0.49 vs 6.17 +/- 1.72, P < .001) were observed. Both groups had a significantly decreased Child-Pugh score; group B had a more persistent and significantly higher reduction. CONCLUSION: Expanded PTFE-covered stent-grafts significantly increased primary patency rate of TIPS in patients with Budd-Chiari syndrome, with reduced reintervention rate and prolonged clinical improvement.     

Efficacy of a Dexamethasone-Eluting Nitinol Stent on the Inhibition of Pseudointimal Hyperplasia in a Transjugular Intrahepatic Portosystemic Shunt: An Experimental Study in a Swine Model

Objective

We wanted to evaluate the feasibility and efficacy of using a dexamethasone (DM)-eluting nitinol stent to inhibit the pseudointimal hyperplasia following stent placement in the transjugular intrahepatic portosystemic shunt tract (TIPS) of a swine.

Materials and Methods

Fifteen stents were constructed using 0.15 mm-thick nitinol wire; they were 60 mm in length and 10 mm in diameter. The metallic stents were then classified into three types; type 1 and 2 was coated with the mixture of 12% and 20%, respectively, of DM solution and polyurethane (PU), while type 3 was a bare stent that was used for control study. In fifteen swine, each type of stent was implanted in the TIPS tract of 5 swine, and each animal was sacrificed 2 weeks after TIPS creation. The proliferation of the pseudointima was evaluated both on follow-up portogram and pathologic examination.

Results

One TIPS case, using the type 1 stent, and two TIPS cases, using the type 2 stent, maintained their luminal patency while the others were all occluded. On the histopathologic analysis, the mean of the maximum pseudointimal hyperplasia was expressed as the percentage of the stent radius that was patent, and these values were 51.2%, 50% and 76% for the type 1, 2, and 3 stents, respectively.

Conclusion

The DM-eluting stent showed a tendency to reduce the development of pseudointimal hyperplasia in the TIPS tract of a swine model with induced-portal hypertension.     

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.     

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.     

Added Value of Covered Stents in Transjugular Intrahepatic Portosystemic Shunt: A Large Single-Center Experience

Purpose

Transjugular intrahepatic portosystemic shunts (TIPS) were historically placed using uncovered bare-metal stents. Current practice has now shifted toward the use of polytetrafluoroethylene (PTFE)-covered stents, given the improved primary patency seen with these stents. The aim of this study was to determine whether there is any added value, such as overall survival or stent patency, when using covered stents versus uncovered stents in TIPS placement in a large cohort.

Materials and Methods

From April 1995 to June 2012, a total of 744 consecutive adult patients underwent de novo TIPS placement (378 receiving uncovered stents, 366 receiving covered stents). Information was obtained on demographics, baseline clinical variables, and outcomes after TIPS placement. Data were collected, compared, and analyzed to assess outcomes including mortality, primary patency (determined via repeat intervention), and secondary patency (determined via ultrasound parameters).

Results

Covered stents were associated with significantly improved primary patency (P < 0.001) and secondary patency (P < 0.001) when compared with uncovered stents in TIPS procedures. Additionally, covered stents were associated with higher estimated overall survival rates and higher survival rates when TIPS was performed emergently and in patients with higher Model for End-Stage Liver Disease (MELD) scores. For example, in patients with MELD scores between 11 and 18, there was a predicted survival of 59.2% with covered stents versus 42.8% with uncovered stents at 1 year.

Conclusion

This study demonstrated that covered stents offer the additional value of higher estimated overall survival and higher estimated survival in patients undergoing TIPS emergently and in those with higher MELD scores when compared to uncovered stents.

     

Transjugular intrahepatic portosystemic shunt with an autologous vein-covered stent: results in a swine model.

PURPOSE: To investigate the feasibility, safety, and efficacy of an autologous vein-covered stent (AVCS) to prevent shunt stenosis in a porcine transjugular intrahepatic portosystemic shunt (TIPS) model. MATERIALS AND METHODS: TIPS were created with an AVCS in 12 healthy domestic swine and with a bare stent in 10 additional swine. Tissue response was compared with use of venography, histology, and computerized morphometry analysis 2 weeks after implantation. Differences between AVCS and noncovered stents (established by a t-test), as well as regional differences within a single stent (established by an f test), were considered significant at P <.05. RESULTS: Twenty of 22 TIPS procedures were technically successful. Ten of 12 shunts with an AVCS (83%) and two of 10 with bare stents (20%) remained patent (<50% diameter narrowing) at euthanasia 2 weeks later (P <.01). Histologic evaluation of harvested bare stents showed marked intimal hyperplasia (IH), composed of smooth muscle cells, myofibroblasts, and fibroblasts. In contrast, the AVCS were remarkably free of IH and thromboses. In patent TIPS in both groups, endothelial coverage of the luminal surface was present histologically. IH accounted for 57% (26.27/45.79) of total stent cross-sectional lumen area in the control group and 21% (8.34/39.54) in the AVCS group (P <.01), with no intrashunt differences (P >.05). CONCLUSION: Based on short-term follow-up, AVCS significantly improved TIPS patency by prevention of both IH and in-stent thrombosis. TIPS created with an AVCS was feasible and safe in our porcine model.     

内皮祖细胞种植支架在经颈静脉肝内门体分流术中应用的实验研究

目的 评价内皮祖细胞(EPC)种植支架在经颈静脉肝内门腔分流(TIPS)家猪动物模型中减少分流道再狭窄的疗效.方法 体外分离、培养、鉴定家猪外周血内皮祖细胞,并构建内皮祖细胞种植支架.15头家猪行TIPS介入手术,采用随机区组设计分为EPC种植支架组9头(实验组),裸支架组6头(对照组).术后14 d行直接门静脉造影,然后处死动物,作病理分析及免疫组织化学检查,记录分流道狭窄及阻塞率,并用图像处理软件计算TIPS分流道假性内膜厚度及面积.计数资料用Fisher精确概率法,计量资料行t检验,作统计学分析.结果 15头猪TIPS手术均成功.实验组分流道通畅5头,狭窄2头(狭窄率50%、70%),阻塞2头(共9头).对照组狭窄1头(狭窄率80%),阻塞5头(共6头).2组通畅率差异有统计学意义(P=0.03).实验组假性内膜增生的厚度(肝静脉、肝实质、门静脉段)显著小于对照组[分别为(1.0 ±0.6)、(0.9±0.5)、(1.0±0.4)mm和(1.2±0.4)、(1.3±0.5)、(1.5±0.4)mm,P值均＜0.05].免疫组织化学显示实验组中通畅的分流道有完整的内皮形成;再狭窄分流道的假性内膜主要由胶原纤维组成,而通畅分流道的假性内膜主要由细胞成分组成.结论 体外构建EPC种植支架是可行的,置入后促进了家猪模型TIPS分流道内皮化形成,可以提高分流道的通畅性.     

Stent-grafts for de novo TIPS: technique and early results

PURPOSE: To evaluate the potential benefits of placing a polytetrafluoroethylene (PTFE)-covered stent-graft during initial creation of a transjugular intrahepatic portosystemic shunt (TIPS) in clinical practice. MATERIALS AND METHODS: De novo TIPS were created with a PTFE stent-graft in four male and four female patients with symptomatic portal hypertension awaiting liver transplant. Their ages ranged from 35 to 62 (mean, 47) years. Patients were followed with TIPS ultrasound (US) and/or venography until liver transplantation or death; one remains under active study. Six recovered specimens underwent gross and microscopic evaluation. RESULTS: All TIPS placements were successful. Six shunts were primarily patent, with a mean patency of 289 days, through completion of the study. Five were found to be patent at transplant and one was found to be patent at autopsy. Explant evaluation revealed a smooth, thin layer of neointima and exclusion of biliary secretions. Three patients developed a total of four stenoses (one tandem lesion) during follow-up, leading to revision in two patients. Mean primary and total patency in these patients was achieved after 279 and 463 days, respectively. A previously occult moderate stenosis was detected after explant in another patient. Only one (nonsignificant) stenosis clearly developed in an area covered by PTFE. CONCLUSION: Placement of a de novo PTFE stent-graft during TIPS creation is feasible and may extend primary shunt patency. Appropriate positioning of the stent-graft is critical.     

Recurrent TIPS thrombosis after polyethylene stent-graft use and salvage with polytetrafluoroethylene stent-grafts

Increasing data support the use of polytetrafluoroethylene (PTFE) stent-grafts for de novo and revision transjugular intrahepatic portosystemic shunt (TIPS) applications. Animal experiments have indicated that polyethylene terephthalate (PET) stent-grafts provide no improvement or actually worsen TIPS patency compared with controls, but human TIPS experience with PET grafts is more limited. Herein we describe three patients who underwent de novo creation of TIPS with PET-covered stent-grafts at outside institutions, which resulted in immediate and recurring TIPS thromboses despite repeated thrombectomies. After the failed TIPS were revised with PTFE stent-grafts, the presenting symptoms resolved and uninterrupted patency was achieved.     

门静脉金属内支架置入治疗门静脉海绵样变

目的：探讨经皮肝穿刺和经颈内静脉肝内门体分流术(TIPS)途径门静脉内支架置入治疗门静脉海绵样变(CTPV)的疗效及安全性。方法回顾性分析于本科治疗的8例 CTPV 患者的临床及影像学资料。所有患者均行门静脉金属内支架置入治疗,其中3例经 TIPS 途径放置,5例经经皮肝穿刺途径放置。结果所有患者支架置入均一次性成功,无腹腔内出血等严重并发症发生。术中即刻复查造影显示支架内血流通畅,术后1 d~2周患者腹痛及消化道出血症状均明显减轻或消失。术后所有患者均获得完整随访,随访1个月~3年,1例患者术后1 年复查支架闭塞,再次置入1枚支架后血流通畅,其余患者彩超提示支架内血流通畅,未再发消化道出血或腹痛。结论经皮肝穿刺或经 TIPS 途径门静脉金属内支架置入治疗 CTPV 是一种安全有效方法。     

Transjugular intrahepatic portocaval shunt (TIPS) and hepatic vein-to-caval stenting as salvage treatment of portal hypertension secondary to neoplasm

A percutaneous transjugular intrahepatic portocaval shunt (TIPS) was successfully performed using Wallstents in a 53-year-old man with neoplastic disease causing portal hypertension and life-threatening variceal hemorrhage. Shortly after-wards, recurrent hemorrhage was investigated by shunt venography which showed that extrinsic narrowing of the hepatic vein and hepatic vena cava was causing shunt thrombosis. Shunt thrombosis was cleared by balloon occlusion of the shunt and forceful retrograde flushing of thrombus into the portal circulation. The compressed hepatic vein and vena cava were then dilated and stented using Gianturco “Z” stents. Bleeding recurred 3 months later due to focal narrowing within the shunt which possibly was due to intimal proliferation. Repeat dilatation and placement of a coaxial Palmaz stent again relieved portal hypertension. Creation of a TIPS for portal hypertension secondary to neoplasm can produce valuable palliation. Complete assessment of hepatic vein and vena cava patency is required to ensure shunt function.     

Intravascular ultrasound-guided direct intrahepatic portacaval shunt: midterm follow-up

PURPOSE: To describe the midterm patency and clinical results of the intravascular ultrasound (US)-guided direct intrahepatic portacaval shunt (DIPS) procedure for the treatment of intractable ascites and variceal bleeding. MATERIALS AND METHODS: From February 23, 1999, to December 18, 2002, inferior vena cava (IVC)-to-portal vein (PV) shunts were created in 40 patients for ascites (n = 35) and bleeding (n = 5). Intravascular US was used to guide direct puncture from the IVC to the PV. The shunts were completed with the use of single (n = 15) or overlapping (n = 25) polytetrafluoroethylene (PTFE)-covered Palmaz stents. These stent-grafts were deployed primarily at diameters of 8 mm. The diameter of the shunt was increased in three cases to achieve a target portosystemic gradient (PSG) of 15 mm Hg or lower. All patients were followed clinically and with portography with manometry. RESULTS: All DIPSs were created successfully. Mean PSGs were reduced from 23 mm Hg before DIPS creation to 9 mm afterward. During the follow-up period of a maximum of 38 months, 22 of 40 patients died or underwent liver transplantation (mean follow-up, 9 months; median, 6 months). At the time of this report, 18 of 40 patients remain living after follow-up ranging in duration from 8 to 38 months (mean, 22 months; median, 16.5 months). During the follow-up period, there was one stent-graft occlusion and three stenoses. These four patients were successfully treated by additional stent-graft placement. In addition, two patients developed IVC stenosis cephalad to the DIPS, which required IVC stent placement. The primary patency rates by Kaplan-Meier analysis were 100% at 6 months and 75% (95% CI, 53%-97%) at 12 months. CONCLUSION: Intravascular US-guided direct IVC-to-PV shunts may be created successfully with minimal complications. Primary patency of the shunt is greater than that with conventional TIPS with a bare wire stent and appears equal to that with TIPS with a PTFE-covered stent-graft.     

Primary Patency of Wallstents in Malignant Bile Duct Obstruction: Single vs. Two or More Noncoaxial Stents

The purpose of this study was to determine the primary patency of two or more noncoaxial self-expanding metallic Wallstents (Boston Scientific, Natick, MA) and to compare this with the primary patency of a single stent in malignant bile duct obstruction. From August 2002 to August 2004, 127 patients had stents placed for malignant bile duct obstruction. Forty-five patients were treated with more than one noncoaxial self-expanding metallic stents and 82 patients had a single stent placed. Two patients in the multiple-stent group were lost to follow-up. The primary patency period was calculated from the date of stenting until the first poststenting intervention for stent occlusion, death, or the time of last documented follow-up. The patency of a single stent was significantly different from that of multiple stents (P = 0.0004). In the subset of patients with high bile duct obstruction, the patency of a single stent remained significantly different from that of multiple stents (P = 0.02). In the single-stent group, there was no difference in patency between patients with high vs. those with low bile duct obstruction (P = 0.43). The overall median patency for the multistent group and the single-stent group was 201 and 261 days, respectively. In conclusion, the patency of a single stent placed for malignant low or high bile duct obstruction is similar, and significantly longer than, that of multiple stents placed for malignant high bile duct obstruction. Given the median patency of 201 days, when indicated, percutaneous stenting of multiple bile ducts is an effective palliative measure for patients with malignant high bile duct obstruction.     

Retrospective Comparison of the Patency of Wallstents and Palmaz Long-Medium Stents Used for TIPS

Purpose: To compare patency rates of transjugular intrahepatic portosystemic shunts (TIPS) after placement of long-medium Palmaz stents or Wallstents. Methods: We performed a retrospective review of TIPS performed at our institution between December 1997 and December 1998. During this time period we placed long-medium Palmaz stents for TIPS procedures in 17 patients and Wallstents in 20 patients as the initial stent. Patency was determined on follow-up by ultrasound, angiography, or pathologic examination in the event of transplant. Results: Primary patency in the Palmaz stent group was 70.6% (12/17 patients) (follow-up 1–399 days, mean 127 days). Both primary assisted and secondary patency in the Palmaz group was 100% (17/17 patients) (follow up 1–399 days, mean 154 days). Primary patency in the Wallstent group was 50% (10/20 patients) (follow up 1–370 days, mean 65 days). Primary assisted patency in the Wallstent group was 80% (16/20 patients) (follow up 1–601 days, mean 141 days). Secondary patency in the Wallstent group was 100% (20/20 patients) (follow up 2–601 days, mean 142 days). Kaplan-Meier analysis of the two groups of patients yielded a primary patency of 266 days (standard error 45 days) for TIPS with the Palmaz stent and 139 days (standard error 45 days) for the Wallstent (p = .04). The 3, 6, and 12-month primary patency rates were .84, .63, and .42 respectively for the Palmaz stents and .36, .36, and .18 respectively for the Wallstent. There was no significant difference in primary assisted or secondary patency between the two stent groups. The mean tract curvature in the patients with Palmaz stents was 23.5° (SD 18.2°, range 0–69.0°) compared with 57° (SD 34.5°, range 7.0–144.0°) in patients with Wallstents (p = .01). Conclusions: Our nonprospective, nonrandomized study suggests that TIPS created with the long-medium Palmaz stent have a higher primary patency than those created with the Wallstent in tracts that are relatively straight.