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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

Stent impact on the geometry of the carotid bifurcation and the course of the internal carotid artery

A measurement system is proposed to evaluate reconstructive effects of carotid stents on the geometry of the carotid bifurcation and the course of the internal carotid artery. To describe deviations of the stenotic internal carotid artery (ICA) from the extended axis of the common carotid artery (CCA) the CCA-ICA angle is measured between the CCA midaxis and the midaxis of the stenotic ICA segment. Maximal extensions of ICA tortuosities perpendicular to the course of the CCA axis are defined as ICA offset. The measurements were applied to DSA images of 224 carotid stenoses to evaluate variation and correlation between the two parameters. Comparative pre- and post-stent evaluation was performed in two series of 55 and 31 carotid stenoses treated with Wallstents and in a historic control group of 35 stenoses treated with Strecker stents. Straight course of the ICA was associated with low angle and low offset values, whereas tortuous course of the ICA showed larger angle and offset. A moderate linear correlation between the two parameters was found. Corresponding to a straightening of the stented segment, Wallstents reduced mean angle and offset values significantly. In five cases of the second series of Wallstents, transferrals of curves above the distal stent end associated with kinks were observed, and offset remained constant or increased. Strecker stent implantation caused no significant changes of bifurcational geometry. The proposed parameters corresponded to visual aspects of ICA tortuosity and detected reconstructive effects of self-expanding Wallstents on the ICA course. The measurement system may provide a basis for geometric evaluation of different stent types or implantation concepts with the aim: to optimize anatomic recanalization results in tortuous high angle-high offset bifurcations.     

Venous stenoses in dialysis shunts: treatment with self-expanding metallic stents

A flexible, self-expanding metallic endoprosthesis was employed for the treatment of venous outflow stenoses in four patients with a polytetrafluoroethylene shunt and two patients with a Brescia-Cimino shunt. The stenoses had led to shunt occlusion in five patients and to flow impairment in one. In the occluded shunts, thrombectomy and subsequent balloon angioplasty were performed in four patients, and percutaneous recanalization with angioplasty was performed in one. One shunt with decreasing flow was percutaneously dilated. Since the underlying stenoses recurred in four patients after 24 hours and did not respond sufficiently to angioplasty in two patients, up to four stents were placed in the venous segments. Thrombosis of the stents occurred in two patients after 24 hours and in one after 6 weeks and was successfully recanalized with thrombectomy in two. At 2-6 months follow-up, the stents and the shunts were patent in five patients. In three of these patients, intima hyperplasia, associated with narrowing of the stent lumen in two, was noted within 4 months after stent placement.     

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.     

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.     

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.     

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.     

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.     

Porous and nonporous polycarbonate urethane stent-grafts for TIPS formation: biologic responses.

PURPOSE: To evaluate the biologic response to transjugular intrahepatic portosystemic shunts (TIPS) lined with polycarbonate urethane endografts and the effects of different porosity formulations. MATERIALS AND METHODS: Seventeen TIPS were created in non-modified portal hypertensive miniswine with use of porous (n = 6), nonporous (n = 7) polycarbonate urethane stent-grafts, and control Wallstents TIPS (n = 4). Eight-week venography, histology, scanning electron microscopy, and immunohistochemical analyses were performed. RESULTS: The mean 8-week percent parenchymal tract shunt stenosis was 75%, 46%, and 26% in the control, porous, and nonporous groups, respectively. Occlusions developed in one control, one porous, and two nonporous shunts. The biologic response to porous grafts included marked inflammation and encapsulation and permeation of the grafts by a thick fibrous pseudointima. Nonporous grafts evoked little inflammation or pseudointima. Mature thrombus lined the occluded shunts (under which little luminal pseudointima or endothelium was present). The control group showed typical pseudointimal hyperplasia enveloping the intraparenchymal portions of the stents. CONCLUSIONS: The healing response of the porous and nonporous grafts markedly differed. Unlike the porous grafts and control stents, the nonporous endografts elicited little inflammation or luminal pseudointimal hyperplasia, although sporadic thrombosis was problematic in this normotensive model. Graft use in high-flow situations (ie, human TIPS, possibly in concert with antiplatelet agents) may allow desired shunt patency prolongation.     

Covered stents in transjugular portosystemic shunt: healing response to non-porous ePTFE covered stent grafts with and without intraluminal irradiation

The aim of this study was to evaluate the healing response to a new commercially available ePTFE-covered stent graft used to create transjugular intrahepatic portosystemic shunts (TIPS) in an animal model with and without intraluminal irradiation. The study was designed for ten domestic normotensive pigs. The TIPS was created using a ePTFE-covered stent graft (Viatorr, Gore, Flagstaff, Ariz.). Five animals were scheduled for intraluminal irradiation with iridium 192 immediately after TIPS creation with a dosage of 18 Gy. Shunt venograms were performed every 2 weeks. Animals from the irradiated and non-irradiated group were killed at 2-week intervals. Maximum follow-up was planned for 8 weeks in each group, with two animals in reserve. Gross specimen evaluation and histological examination, including scanning electron microscopy, was performed. Two animals died from interventional complications. In the irradiation group, one shunt occlusion and one stenosis occurred after 2 weeks. The stenosis regressed until the end of the 8-week follow-up period and probably was caused by a resolving thrombus. In the non-irradiated group, no shunt dysfunction was observed. One animal died early due to encephalopathy. Histology revealed an increased inflammatory reaction in the irradiation group, a lesser degree of incorporation of the stent graft, and a lesser degree of endothelialization of the inner surface compared with the non-irradiated group. No significant foreign body reaction was found at any time in any of the animals. The Viatorr stent graft was well tolerated in the pig model. Intraluminal irradiation seemed to have an adverse effect on the healing response. The TIPS patency was prolonged in both the irradiated and non-irradiated group compared with data from the literature; however, seemingly better results were observed in the non-irradiated group.     

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.     

Iliac artery stenting--clinical experience with the Palmaz stent, Wallstent, and Strecker stent.

A total of 82 iliac artery lesions (62 stenoses and 20 occlusions) were treated with 3 different types of endovascular metallic stents (12 lesions with the Palmaz stent, 36 with the Wallstent, and 34 with the Strecker stent). The complication rate was 12%. Occlusion of 2 Wallstents occurred 4 and 12 weeks after stent placement, respectively. Both stents were recanalized by local fibrinolysis. One Strecker stent occluded after 8 months. The observation period was 3 to 26 months (mean 9.7 months). The patency rate with secondary intervention (fibrinolysis) was 100% after 3 and 6 months, and 98% after 9 months. All 3 stent designs turned out to be effective in the treatment of complicated iliac artery occlusive disease.