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.     

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.     

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.     

肝内门腔分流术支架与血管支架组织成分的对比研究

目的 对比研究经猪颈静脉肝内门腔分流术(TIPS)与血管支架术后组织成分的异同,为TIPS与血管支架再狭窄的形成机制及防治提供更多的信息.方法 对6只25 kg的家猪进行TIPS术,建立TIPS猪模型,并行髂静脉支架置入术.14～28 d后处死,取出肝脏TIPS组织及支架段静脉绀织做病理检查,包括大体标本检查、电镜检查,病理切片行HE染色,免疫组织化学(简称免疫组化)分析抗平滑肌肌动蛋门-α、细胞增殖核抗原(PCNA)、波形蛋白、肌球蛋白表达,蛋白印迹(Western blot)分析转化牛长因子-β(TGF-β)表达.将TIPS组织与血管支架组织进行上述多项指标的对比分析.所获数据进行Kruskal Wallis秩和检验.结果 动物处死时,6只猪有4只,TIPS通道出现不同程度再狭窄,其中有2只TIPS通道完全堵塞,而髂静脉支架置入术后静脉支架均通畅,仅见支架通道内壁为一薄层内膜组织覆盖,腔内尤狭窄.电镜检查,TIPS再狭窄组织较为稀疏,较多胶原基质与纤维,细胞成分少至中等量,细胞形态多样且不规则,可见平滑肌细胞、少量成纤维细胞及成肌纤维细胞,细胞含丰富分泌颗粒;TIPS支架通畅组织可见大量胶原纤维,含中等量的细胞成分,主要是成纤维细胞及平滑肌细胞,细胞器幕本正常.支架段静脉组织含大量胶原纤维,细胞成分较多,主要为成纤维细胞,平滑肌细胞较少.免疫组化检测:抗平滑肌肌动蛋白-α,TIPS再狭窄组织表达强阳性,TIPS通畅组织表达也较强,支架段静脉组织表达较强,但阿性细胞明显稀疏;PCNA在TIPS冉狭窄组织表达强阳性,在,TIPS通畅组织表达也较强,在支架段静脉组织表达明显较弱;波形蛋白在支架段静脉组织表达较强,在通畅的TIPS支架通道组织中为阳性表达,而在TIPS支架再狭窄组织中表达减弱;肌球蛋白在TIPS再狭窄组织表达为弱阳性,而在TIPS通畅的支架组织与支架段静脉组织表达更弱.Western blot检测TGF-β,支架段静脉组织、正常静脉组织对照、正常肝组织埘照、TIPS狭窄组织及TIPS通畅组织的吸光度比值(TGF-β/β肌动蛋白)中位数分别为0.23、0、0、 0.57、0.30,对所获条带的光密度比值进行统计学分析,差异有统计学意义(H=27.8,P＜0.01).结论 猪模型中,TIPS再狭窄组织中主要为抗平滑肌肌动蛋白-α阳性的平滑肌细胞增殖,细胞增殖迁移能力强,细胞型稳定件低;通畅的TIPS组织与支架段静脉组织相似,表达波形蛋白的成纤维细胞较多,细胞较稳定.     

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.     

经颈静脉肝内门体静脉内支架分流术术式改良的实验研究

目的：探讨建立改良式猪经颈静脉肝内门体静脉内支架分流术（TIPSS）模型的可行性及其意义。方法：11只家猪分成2组，7只采用改良术式（经肝段下腔静脉穿刺门脉）建立TIPSS模型，另4只行常规TIPSS作对照。共置入4枚进口覆膜镍钛合金支架，8枚国产覆聚氨酯膜支架。其中，改良组7只猪置入7枚支架（4枚进口支架，3枚国产支架）；对照组4只猪置入5枚国产覆膜支架（1只猪置入时支架发生移位，故加用1枚支架）。术后4周（5只），8周（2只）和12周（4只）进行门脉造影观察分流道通畅情况。动物处死后，行分流道大体和组织病理学检查。结果：术后4周，改良组2只分流道通畅（进口支架、国产支架各1枚），分流道表面均形成完整的假性内膜组织；另5只分流道在4至12周均闭塞，分流道内形成血栓，其中2只内支架伸入下腔静脉内不全，陷入肝实质内。常规组4只分流道在4、8和12周观察期内均闭塞。两组间分流道肝（下腔）静脉端，肝实质段和门静脉端各段的增生组织厚度对比差异均无显著性意义（t值分别为0．14、0．16和0．20，P值均＞0．05）。结论：改良式猪TIPSS模型的建立是安全和可行的。改良式TIPSS中应采用覆膜支架，并应有足够长度伸入至两端静脉内，有助于防止增生组织向分流道内长入。     

Endovascular shunt reduction in the management of transjugular portosystemic shunt-induced hepatic encephalopathy: preliminary experience with reduction stents and stent-grafts

OBJECTIVE: The purpose of this study was to retrospectively evaluate the safety, feasibility, and midterm clinical outcome of the use of three types of reduction stents inserted to manage transjugular intrahepatic portosystemic shunt (TIPS)-induced hepatic encephalopathy refractory to medical treatment. CONCLUSION: The use of a covered reduction stent-graft results in a greater increase in portosystemic gradient immediately after reduction than does use of a bare reduction stent. Relief of TIPS-induced hepatic encephalopathy tends to be greater in patients with reduction stent-grafts than in those with bare reduction stents.     

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.     

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.     

Self-expanding stents in transjugular intrahepatic portosystemic shunt: experience with nitinol Strecker stents

The aim of our study was to evaluate the performance and efficacy of a new self-expanding stent (nitinol Strecker stent) in the transjugular intrahepatic portosystemic shunt (TIPS) procedure. We have successfully placed 64 nitinol Strecker stents in 48 patients. The average portosystemic gradient decreased from 22 to 11 mm Hg. Balloon dilatation was necessary in 12 of 35 angiographically controlled cases at 5 days (34%), because of incomplete stent expansion, small thrombi within the stent or obstruction. At 1–6 months stent malfunctions occurred in 8 of 23 patients who underwent control angiography (34%) and at 6–24 months in 6 of 7 patients (85%). Rebleeding occurred in 2 of 39 patients (follow-up > 1 month) (5%) and temporary crises of de novo encephalopathy were observed in 11 of 48 patients (23%). Refractory ascites completely resolved in 4 of 6 patients (66%) and improved in the remaining 2 cases. Compared with other self-expanding stents, nitinol Strecker stents seem to be equally effective in TIPS; no increase in complication rate was observed, either clinical or stent-related. Correspondence to: P. Rossi     

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.     

Bile resistance of coated transjugular intrahepatic portosystemic shunt stents in a flow-model

PURPOSE: We sought to test the bile resistance of transjugular intrahepatic portosystemic shunt (TIPS) stents with 3 different coatings. MATERIALS AND METHODS: Three stents with different coating materials (monolayer polyethylene terephthalate [PETP], monolayer polytetrafluoroethylene [PTFE], and double layer [PTFE]) were tested in a flow model. After testing the sealing of the system with isotonic saline solution, fresh human bile was circulated. Constant pressure was 50 cm H2O. Bile resistance of the stent membranes was analyzed. RESULTS: Two of the 3 stents proved completely resistant to water. Only the PETP stent was resistant to bile. The PTFE-coated stents were not bile resistant. CONCLUSION: The bile resistance of coated TIPS stents and, thus, the dependency of TIPS shunt patency is called into question. The stent with the reported superior patency rates does not show experimental bile resistance.     

Intraluminal irradiation for TIPS stenosis: preliminary results in a swine model.

PURPOSE: To evaluate the ability of 32phosphorus intraluminal irradiation to reduce pseudointimal hyperplasia in a transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: TIPS were successfully placed in 11 swine with normal portal pressures. Six animals received 15.2 Gy intraluminal irradiation to the hepatic parenchyma and venous outflow tract at the time of TIPS placement with use of a NA32P-filled balloon angioplasty catheter. Five control animals underwent TIPS and balloon angioplasty with saline. All animals were followed up for 28 days, at which time percutaneous portography was performed, the animals were killed, and the tissue around the TIPS stent was processed for histologic analysis. Maximum pseudointimal hyperplasia as a percentage of estimated TIPS diameter was calculated for each animal. RESULTS: At the time of euthanasia, all five control TIPS and all but one irradiated TIPS were occluded. Histologic analysis demonstrated considerable variability in the degree of pseudointimal hyperplasia within each TIPS and between animals. No statistically significant difference was found in the maximum pseudointimal hyperplasia, measured as a percentage of stent radius, between control (80.2%+/-17.4%) and irradiated animals (69.2%+/-25.2%). CONCLUSIONS: Irradiation of TIPS with 15.2 Gy 32P delivered at the time of TIPS placement did not significantly improve TIPS patency or reduce the degree of pseudointimal hyperplasia in swine with normal portal pressures.     

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.     

Effects of Intraluminal Irradiation with Holmium-166 for TIPS Stenosis: Experimental Study in a Swine Model

Objective

We wanted to evaluate the effectiveness of intraluminal irradiation with Holmium-166 (¹⁶⁶Ho) for reducing the pseudointimal hyperplasia (PIH) in the transjugular intrahepatic portosystemic shunt (TIPS) tract in a swine model.

Materials and Methods

TIPS was performed in 12 domestic pigs, after the creation of portal hypertension by intraportal injection of a mixture of N-butyl-2-cyanoacrylate (NBCA) and lipiodol. Five pigs first underwent intraluminal irradiation (30 Gy) in the parenchymal tract with using a ¹⁶⁶Ho solution-filled balloon catheter, and this was followed by the placement of a nitinol stent in the TIPS tract. For the seven control pigs, the balloon was filled with saline and contrast media mixture. Two weeks later, follow-up portography and histological analysis were performed.

Results

TIPS was successfully performed in all twelve pigs with achieving artificially induced portal hypertension. Portography performed two weeks after TIPS showed the patent tracts in the TIPS tracts that were irradiated with ¹⁶⁶Ho (5/5, 100%), whereas either completely (5/6, 83.3%) or partially (1/6, 16.7%) occluded TIPS were seen in the seven pigs of the nonirradiated control group, except in one pig that experienced periprocedural death due to bleeding. Histological analysis showed a statistically significant difference for the maximal PIH (irradiated: 32.8%, nonirradiated: 76.0%, p < 0.001) between the two groups.

Conclusion

Intraluminal irradiation with 30 Gy of ¹⁶⁶Ho for TIPS significantly improved the TIPS patency in a swine model of portal hypertension during a 2-week period of follow-up.     

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 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.     

Heparin-coated balloon-expandable stent reduces intimal hyperplasia in the iliac artery in baboons

PURPOSE: To examine the effect of heparin-coated balloon-expandable iliac stent placement on intimal hyperplasia in a baboon model. MATERIALS AND METHODS: Balloon-expandable (Palmaz-Schatz) stents were placed in bilateral common iliac arteries in 20 male baboons (mean weight: 8.8 kg). In each animal, a heparin-coated iliac stent was placed on one side and the contralateral iliac artery received an uncoated stent that served as a control. The iliac artery stents were harvested at 30 days (n = 10) and 90 days (n = 10). Arteriography was performed to assess iliac patency and intravascular ultrasonography was used to determine neointimal and luminal areas. Histologic and morphometric analysis and scanning electron microscopy were performed in the stent-implanted iliac arteries. RESULTS: One animal was excluded in the 30-day group because of premature death. In the remaining nine surviving animals, seven control stents (78%) and nine heparin-coated stents (100%) remained patent. Morphometric analysis showed that the iliac arteries with heparin-coated stents had larger luminal areas (17%, P <.05), less neointimal area (26%, P <.05), lower neointima-to-media ratios (32%, P <.05), and equivalent medial areas (P =.92) compared to the control group at 30 days. In contrast, all control and heparin-coated stents were patent (100%) in the 90-day group. In that group, the heparin-coated stent group had less neointimal area (28%, P <.05), lower neointima-to-media ratios (42%, P <.05), and equivalent medial area (P =.92) and luminal area (P =.07) compared to the control group. CONCLUSIONS: The data demonstrate that heparin-coated balloon-expandable stents reduce intimal hyperplasia after iliac artery stent placement. This approach may represent a useful strategy for prolonging luminal patency after iliac stent placement.     

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.     

Outcomes of Prosthetic Hemodialysis Grafts after Deployment of Bare Metal versus Covered Stents at the Venous Anastomosis

Purpose

To compare postintervention patency rates after deployment of bare metal versus covered stents across the venous anastomosis of prosthetic arteriovenous (AV) grafts.

Methods

Review of our procedural database over a 6?year period revealed 377 procedures involving stent deployment in an AV access circuit. After applying strict inclusion criteria, our study group consisted of 61 stent deployments in 58 patients (median age 58?years, 25 men, 33 women) across the venous anastomosis of an upper extremity AV graft circuit that had never been previously stented. Both patent and thrombosed AV access circuits were retrospectively analyzed. Within the bare metal stent group, 20 of 32 AV grafts were thrombosed at initial presentation compared to 18 of 29 AV grafts in the covered stent group.

Results

Thirty-two bare metal stents and 29 covered stents were deployed across the venous anastomosis. The 3, 6, and 12?months primary access patency rates for bare metal stents were not significantly different than for covered stents: 50, 41, and 22?% compared to 59, 52, and 29?%, respectively (p?=?0.21). The secondary patency rates were also not significantly different: 78, 78, and 68?% for bare metal stents compared to 76, 69, and 61?% for covered stents, respectively (p?=?0.85). However, covered stents demonstrated a higher primary stent patency rate than bare metal stents: 100, 85, and 70?% compared to 75, 67, and 49?% at 3, 6, and 12?months (p?Conclusion The primary and secondary access patency rates after deployment of bare metal versus covered stents at the venous anastomosis were not significantly different. However, bare metal stents developed in-stent stenoses significantly sooner.