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

Creation of 6- to 10-mm-Diameter Transjugular Intrahepatic Portosystemic Shunts Using a Novel Transjugular Intrahepatic Portosystemic Shunt Stent Graft in a Swine Model

PURPOSE

To assess the delivery, function, and patency of a new expanded polytetrafluoroethylene-encapsulated transjugular intrahepatic portosystemic shunt (TIPS) stent graft ("Liverty") in an animal model.

MATERIALS AND METHODS

TIPS were created in 2 successive groups: (a) 14 single and (b) 10 overlapping devices, in swine weighing 52-64 kg. Explants occurred at 30 (n = 10) and 60 (n = 14) days. These were evaluated by histomorphometric and histopathologic evaluations and electron microscopy.

RESULTS

Seven 6-mm-diameter, 5 7-mm-diameter, and 12 10-mm-diameter TIPSs were created using varied human TIPS access sets without adverse events, both sheathed and unsheathed advancement and deployment of the devices within liver tracts. One animal was sacrificed at 35 days due to encephalopathy; the remainder survived to endpoints. Twenty-two of 24 TIPSs were patent at 30-day and 60-day endpoints. The mean stenosis at 30 days was 13.3% (SD ± 10.1), and that at 60 days was 18.4% (SD ± 5.0). Two shunts were occluded by tissue overgrowth at the stent-free native hepatic vein end and downgrowth into TIPS. Histology and electron microscopy showed well-apposed, incorporated devices lined with smooth, uniform neointimal tissue averaging 0.48 mm (single devices) and 0.74 mm (overlapped devices) thick with minimal adventitial inflammation.

CONCLUSIONS

The new Liverty TIPS stent graft was straightforward to deploy for TIPS creation and resulted in patent 6-mm-diameter, 7-mm-diameter, and 10-mm-diameter shunts in both single and overlapping configurations. One- and 2-month histology showed desired tissue healing without in-stent stenosis.

Transjugular Intrahepatic Portosystemic Shunt: Devices Evolution, Technical Tips and Future Perspectives

Portal hypertension (PH) constitutes a pivotal factor in the progression of cirrhosis, giving rise to severe complications and a diminished survival rate. The transjugular intrahepatic portosystemic shunt (TIPS) procedure has undergone significant evolution, with advancements in stent technology assuming a central role in managing PH-related complications. This review aims to outline the progression of TIPS and emphasizes the significant influence of stent advancement on its effectiveness. Initially, the use of bare metal stents (BMSs) was limited due to frequent dysfunction. However, the advent of expanding polytetrafluoroethylene-covered stent grafts (ePTFE-SGs) heralded a transformative era, greatly enhancing patency rates. Further innovation culminated in the creation of ePTFE-SGs with controlled expansion, enabling precise adjustment of TIPS diameters. Comparative analyses demonstrated the superiority of ePTFE-SGs over BMSs, resulting in improved patency, fewer complications, and higher survival rates. Additional technical findings highlight the importance of central stent placement and adequate stent length, as well as the use of smaller calibers to reduce the risk of shunt-related complications. However, improving TIPS through technical means alone is inadequate for optimizing patient outcomes. An extensive understanding of hemodynamic, cardiac, and systemic factors is required to predict outcomes and tailor a personalized approach. Looking forward, the ongoing progress in SG technology, paired with the control of clinical factors that can impact outcomes, holds the promise of reshaping the management of PH-related complications in cirrhosis.

Expanded polytetrafluoroethylene (ePTFE)-covered stents versus bare stents for transjugular intrahepatic portosystemic shunt in people with liver cirrhosis

BACKGROUND

Transjugular intrahepatic portosystemic shunt (TIPS) is a widely used procedure for management of uncontrolled upper gastrointestinal bleeding and refractory ascites in people with liver cirrhosis. However, nearly half of the people experience shunt dysfunction and recurrent symptoms within one year of the procedure. Expanded polytetrafluoroethylene (ePTFE)-covered stents are assumed to decrease shunt dysfunction by approximately 20% to 30%.

OBJECTIVES

To evaluate the benefits and harms associated with the use of expanded polytetrafluoroethylene (ePTFE)-covered stents versus bare stents in transjugular intrahepatic portosystemic shunts (TIPSs) for managing people with liver cirrhosis.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 28 February 2023.

SELECTION CRITERIA

Randomised clinical trials comparing ePTFE-covered stents versus bare stents in TIPS for treatment of people with liver cirrhosis.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. all-cause mortality, 2. procedure-related complications, and 3. health-related quality of life. Our secondary outcomes were 4. upper gastrointestinal bleeding, 5. recurrence of ascites, 6. hepatic encephalopathy, 7. kidney failure, 8. early thrombosis, 9. non-serious adverse events, and 10. shunt dysfunction. We used GRADE to assess certainty of evidence. We analysed outcome data at the maximum follow-up, except for the 'early thrombosis' outcome for which it was within 12 weeks after the TIPS procedure.

MAIN RESULTS

We included four trials with 565 randomised participants (age range: 18 to 75 years; male range: 63.6% to 75.0%). A total of 527 participants provided data for analyses because of losses to follow-up. Two trials were conducted in China; one in France; and one in France, Spain, and Canada. Participants were classified with cirrhosis Child-Pugh class A, B, or C, and for some, the class was not reported. We used intention-to-treat principle (four trials) and per-protocol analysis (one trial) to meta-analyse the data. One trial compared ePTFE-covered stents versus bare stents of the same diameter and three trials compared ePTFE-covered stents versus stents of different diameters. ePTFE-covered stents versus bare stents of the same diameter One trial with 258 participants compared 8 mm covered stent versus 8 mm bare stent. Mortality in the covered stent group is possibly lower than in the bare stent group (risk ratio (RR) 0.63, 95% confidence interval (CI) 0.43 to 0.92; low-certainty evidence). Upper gastrointestinal bleeding (RR 0.54, 95% CI 0.35 to 0.84), recurrence of ascites (RR 0.42, 95% CI 0.20 to 0.87), and shunt dysfunction (RR 0.42, 95% CI 0.28 to 0.61) occurred more often in the bare stent group than in the covered stent group (all low-certainty evidence). There was no difference in hepatic encephalopathy between groups (RR 1.10, 95% CI 0.76 to 1.61; very low-certainty evidence). The trial did not report data on procedure-related complications, health-related quality of life, early thrombosis, and segmental liver ischaemia (a non-serious adverse event). ePTFE-covered stents versus bare stents of different stent diameters Three trials compared ePTFE-covered stents versus bare stents of different diameters (10.5 (standard deviation (SD) 0.9) mm versus 11.7 (SD 0.8) mm; 8 mm versus 10 mm; and one trial used 10-mm stents that could be dilated from 8 mm to 10 mm). There was no evidence of a difference between the ePTFE-covered stents versus bare stents groups in mortality (RR 0.75, 95% CI 0.48 to 1.16; 3 trials, 269 participants), procedure-related complications (RR 0.53, 95% CI 0.05 to 5.57; 1 trial, 80 participants), upper gastrointestinal bleeding (RR 0.46, 95% CI 0.15 to 1.38; 3 trials, 269 participants), hepatic encephalopathy (RR 0.93, 95% CI 0.66 to 1.30; 3 trials, 269 participants), and kidney failure (RR 7.59, 95% CI 0.40 to 143.92; 1 trial, 121 participants) (all very low-certainty evidence). Recurrence of ascites (RR 0.30, 95% CI 0.11 to 0.85; 3 trials, 269 participants; low-certainty evidence), shunt dysfunction (RR 0.50, 95% CI 0.28 to 0.92; 3 trials, 269 participants; low-certainty evidence), and early thrombosis (RR 0.28, 95% CI 0.09 to 0.82; I2 = 0%; 3 trials, 261 participants; very low-certainty evidence) occurred more often in the bare stents group. There was no evidence of a difference in segmental liver ischaemia (RR 5.25, 95% CI 0.26 to 106.01; 1 trial, 80 participants; very low-certainty evidence). No trial presented data on health-related quality of life. Funding One trial did not clearly report funding sources. The remaining three trials declared that they had no funding with vested interests.

AUTHORS' CONCLUSIONS

Based on the small number of trials with insufficient sample size and events, and study limitations, we assessed the overall certainty of evidence in the predefined outcomes as low or very low. Therefore, we are uncertain which of the two interventions (ePTFE-covered stents or bare stents of the same diameter and ePTFE-covered stents versus bare stents of different stent diameters) is effective for the evaluated outcomes. None of the four trials reported data on health-related quality of life, and data on complications were either missing or rarely reported. We lack high-quality trials to evaluate the role of ePTFE-covered stents for TIPS for managing people with liver cirrhosis.

Comparison of the Covered Self-Expandable Viatorr CX Stent with the Covered Balloon-Expandable BeGraft Peripheral Stent for Transjugular Intrahepatic Portosystemic Shunt (TIPS) Creation: a Single-Centre Retrospective Study in Patients with Variceal Bleeding

PURPOSE

This study compares the safety and efficacy of the ePTFE-covered self-expansible nitinol stent (VIATORR® Controlled Expansion, Gore, Flagstaff, USA) with the ePTFE-covered, balloon-expandable, metallic stent (BeGraft peripheral, Bentley, Hechingen, Germany) for the creation of the transjugular intrahepatic portosystemic shunt (TIPS).

MATERIAL AND METHODS

From September 2016 to December 2020, 72 consecutive patients receiving TIPS for acute variceal bleeding (rescue and early TIPS, n = 15) or for prophylaxis of variceal rebleeding (n = 57) were enrolled. The main contraindications were patients with vascular liver disease (portal vein thrombosis and Budd-Chiari syndrome). Forty patients (55.6%) received a Viatorr CX stent and 32 patients (44.4%) a BeGraft peripheral stent. Safety endpoints were technical and clinical adverse events and early deaths within 30 days after TIPS implantation. Efficacy endpoints were rebleeding rates, recurrence of large varices requiring endoscopic band ligation, or TIPS revision.

RESULTS

Groups receiving the Viatorr CX or BeGraft peripheral stent were comparable in all respects except the TIPS indication for acute variceal bleeding (5% vs. 25%, p = 0.015). All patients had a successful intervention, and the physical variables of stent implantation (intervention and fluoroscopy time, reduction of the portosystemic pressure gradient) as well as adjunctive embolization of varices were similar in both groups. Severe clinical complications (Viatorr CX: 5% vs. BeGraft peripheral: 3.1%, p = 0.692), post-TIPS hepatic encephalopathy (12.5% vs. 18.8%, p = 0.743) and death (5% vs. 0%, p = 0.793) were not different between Viatorr CX and BeGraft peripheral groups. With respect to efficacy, freedom from rebleeding and from variceal band ligation during follow-up (100% vs. 100%, p = 1.0), as well as the need for shunt revision (10.5% vs. 18.8%, p = 0.327), was comparable.

CONCLUSION

Compared to the present gold standard, the Viatorr CX stent, the balloon-expandable BeGraft peripheral stent, showed similar results with respect to safety and efficacy.

Evaluation of a Novel Spun Polytetrafluoroethylene Stent Graft in an Ovine External Iliac Artery Model

PURPOSE

To evaluate the patency, cellular response, and thrombogenicity of a novel vascular stent graft.

MATERIALS AND METHODS

Test stent grafts, incorporating luminal spun polytetrafluoroethylene and a nonpermeable fluoropolymer layer, and control stent grafts, constructed of permeable expanded polytetrafluoroethylene, were implanted in the external iliac arteries of 14 adult sheep with a median weight of 73.4 kg ranging from 60.6-86.8 kg for 30 (n = 4), 90 (n = 4), and 180 (n = 6) days. Angiographic patency and percent diameter stenosis (%DS) were assessed at termination. Excised stent grafts were fixed and stained for histopathologic analysis, including neointimal coverage (NC) assessment.

RESULTS

Test and control device migration occurred in 1 animal, resulting in test device thrombosis. Both devices were excluded from analysis. Mean %DS in test and control implants was 4.6% and 8.2% (P = .563), 2.0% and 10.9% (P = .363), and 2.1% and 10.3% (P = .009) at 30, 90, and 180 days, respectively. Median NC scores at 30, 90, and 180 days were significantly lower in middle test device sections (P < .05). Proximal and distal test and control sections exhibited similar median NC scores at all time periods (P > .05). When present, test and control devices exhibited no neointimal detachment from the graft surface. Except for the migrated test device, no thrombus was observed. Transgraft cellular migration was absent in test devices but present in control devices with tissue accumulation around the stent struts.

CONCLUSIONS

Test and control devices demonstrated excellent patency in an ovine model. Compared to the control, test devices exhibited significantly lower %DS values at 180 days and significantly lower mid-device NC scores at 30, 90, and 180 days.

Shunt stenosis or occlusion after transjugular intrahepatic portosystemic shunt

Transjugular intrahepatic portosystemic shunt (TIPS) has been extensively used to treat the complications of portal hypertension and should be considered the first-line treatment for hemorrhage of acute esophagogastric varices caused by portal hypertension. However, stent stenosis or occlusion after TIPS is the main cause of shunt dysfunction and surgical failure. This paper aims to make a comprehensive review of stents, with the focus being on the development of stents and stent coat material, the reason of shunt stenosis or occlusion, and the revision of shunt.

Should stent-grafts replace bare stents for primary transjugular intrahepatic portosystemic shunts?

Transjugular intrahepatic portosystemic shunt (TIPS) creation using bare stents is a second-line treatment for complications of portal hypertension due in part to the relatively high number of reinterventions and the occurrence of new or worsened encephalopathy. Initially, custom-made stent-grafts were used for TIPS revision in cases of biliary fistulae. Subsequently, custom stent-grafts were used for de novo TIPS creation. With the introduction of the VIATORR(®) TIPS endoprosthesis a dedicated stent-graft became available for TIPS creation and revision. The VIATORR(®) demonstrated its efficacy and superiority to uncovered stents in retrospective analyses, case-matched analyses, and randomized studies. The improved patency of stent-grafts has led many to requestion the role of TIPS as a second-line therapy. Currently, randomized trials are warranted to redefine the role of TIPS in the treatment of complications of portal hypertension.

Causes of TIPS dysfunction

OBJECTIVE

Transjugular intrahepatic portosystemic shunt (TIPS) creation is an effective method to control portal hypertension. TIPS creations with bare stents have shown limited and unpredictable patency. In nearly all cases of rebleeding or recurrent ascites after TIPS creation, there is shunt stenosis or occlusion. The purpose of this article is to review the biologic and technical factors that predispose to TIPS failure and how the use of an expandable polytetrafluoroethylene (PTFE)-covered-stent has significantly improved TIPS patency.

CONCLUSION

Biologic and technical factors may predispose to shunt failure. The combination of improved technique and expandable PTFE has significantly improved TIPS patency. The need for follow-up venography and secondary interventions has been reduced significantly as a result of improved shunt patency.

Intravascular US-guided direct intrahepatic portocaval shunt with an expanded polytetrafluoroethylene-covered stent-graft

PURPOSE

To retrospectively evaluate the midterm patency rate of the nitinol (Viatorr, W.L. Gore and Associates, Flagstaff, Ariz) stent-graft for direct intrahepatic portacaval shunt (DIPS) creation.

MATERIALS AND METHODS

Institutional Review Board approval for this retrospective HIPAA-compliant study was obtained with waiver of informed consent. DIPS was created in 18 men and one woman (median age, 54 years; range, 45-65 years) by using nitinol polytetrafluoroethylene (PTFE)-covered stent-grafts. The primary indications were intractable ascites (n = 14), acute variceal bleeding (n = 3), and hydrothorax (n = 2). Follow-up included Doppler ultrasonography at 1, 6, and 12 months and venography with manometry at 6-month intervals after the procedure. Shunt patency and cumulative survival were evaluated by using the Kaplan-Meier method and survival curves were plotted. Differences in mean portosystemic gradients (PSGs) were evaluated by using the Student t test. Multiple regression analysis for survival and DIPS patency were performed for the following parameters: Child-Pugh class, model of end-stage liver disease score, pre- and post-DIPS PSGs, pre-DIPS liver function tests, and pre-DIPS creatinine levels.

RESULTS

DIPS creation was successful in all patients. Effective portal decompression and free antegrade shunt flow was achieved in all patients. Intraperitoneal bleeding occurred in one patient during the procedure and was controlled during the same procedure by placing a second nitinol stent-graft. The primary patency rate was 100% at all times during the follow-up period (range, 2 days to 30 months; mean, 256 days; median, 160 days). Flow restrictors were deployed in two (11%) of 19 patients. The 1-year mortality rate was 37% (seven of 19).

CONCLUSION

Patency after DIPS creation with the nitinol PTFE-covered stent-graft was superior to that after TIPS with the nitinol stent-graft.

Efficacy of a dexamethasone-eluting nitinol stent on the inhibition of pseudo-intimal 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 pseudo-intimal 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 pseudo-intima 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 pseudo-intimal 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 pseudo-intimal hyperplasia in the TIPS tract of a swine model with induced-portal hypertension.

Acute Effects of Liver Vein Occlusion by Stent-Graft Placed in Transjugular Intrahepatic Portosystemic Shunt Channel: An Experimental Study

The purpose of this study was to evaluate the effects of hepatic vein occlusion by stent-graft used in transjugular intrahepatic portosystemic shunt (TIPS). The experiments were performed in six healthy pigs under general anesthesia. Following percutaneous transhepatic implantation of a port-a-cath in the right hepatic vein, TIPS was created with a stent-graft (Viatorr; W L Gore, Flagstaff, AZ, USA). The outflow from the hepatic vein, blocked by the stent-graft was documented by injection of contrast medium and repeated injections of (99)Tc(m)-labeled human serum albumin through the port-a-cath. After 2 weeks, the outflow was re-evaluated, the pigs were sacrificed, and histopathologic examination of the liver was performed. Occlusion of the hepatic vein by a stent-graft had a short and temporary effect on the outflow. Histopathological examination from the affected liver segment showed no divergent pattern. Stent-grafts used in TIPS block the outflow from the liver vein, but do not have a prolonged circulatory effect and do not affect the liver parenchyma.

Dacron-covered stent-grafts in transjugular intrahepatic portosystemic shunts: initial experience

PURPOSE

To retrospectively review the authors' experience with use of a Dacron-covered stent-graft in transjugular intrahepatic postosystemic shunts (TIPS).

MATERIALS AND METHODS

The need for internal review board approval was waived. Informed consent was obtained from all patients. The study was compliant with the Health Insurance Portability and Accountability Act. A retrospective analysis was performed of 16 patients who received a Dacron-covered stent-graft during revision or de novo creation of TIPS. There were 13 men and three women aged 44-80 years (mean age, 61 years). Primary unassisted and assisted patency rates and secondary patency rates were estimated. The primary unassisted patency of patients who underwent de novo placement of stent-grafts (n = 10) was compared with that of patients with stent-grafts placed during shunt revision (n = 6); in all patients, stent-grafts were placed within stents. Primary unassisted patency was also compared between patients in whom the covered stent was confined to the parenchymal tract (n = 7) and those in whom the stent extended 1 cm or more into the portal vein (n = 9). Patency was estimated with the Kaplan-Meier method, and group comparisons were performed with the log-rank test.

RESULTS

Primary unassisted patency rates following stent-graft placement at 4, 12, and 24 months (+/- standard error) were 64% +/- 14, 54% +/- 15, and 40% +/- 16, respectively. The rates for primary assisted patency were 78% +/- 12, 67% +/- 14, and 67% +/- 14 and those for secondary patency were 91% +/- 9, 81% +/- 12, and 54% +/- 23. At 12 months, primary unassisted patency with de novo stent-graft placement was 90% +/- 9, whereas that with stent-grafts placed during TIPS revision was 17% +/- 15 (P = .005). At 12 months, the primary unassisted patency in patients with stent-grafts confined to the parenchymal tract was 75% +/- 22, and that of patients with stent-grafts extending at least 1 cm into the portal vein was 40% +/- 17 (P = .21).

CONCLUSION

In this small series, satisfactory long-term patency was observed among patients in whom Dacron-covered stent-grafts were placed during revision or de novo creation of TIPS. More favorable outcomes were observed when the stent-graft was placed during de novo TIPS creation and when the device was confined to the parenchymal tract.

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.

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.

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.

Percutaneous inferior vena cava-to-portal vein shunt (PIPS) using a stent-graft: preliminary results

PURPOSE

To present preliminary results of an inferior vena cava (IVC)-to-portal vein shunt (PIPS) that is created through the caudate lobe of the liver.

METHODS

Sixteen patients (13 men; mean age 50 years, range 32-63) were referred for PIPS procedures because of bleeding varices (n = 11), intractable ascites (n = 4), and hepatorenal syndrome (n = 1). The severity of liver disease was Child's B in 2 and Child's C in 14. The PIPS was created by a transhepatic puncture through the IVC and the portal vein; an endograft made of polytetrafluoroethylene sutured to a Palmaz stent was placed through a jugular approach.

RESULTS

In 13 (81%) patients, the portal vein-to-IVC tracts were successfully created. The postprocedural portal vein-IVC gradients varied from 1 to 9 mm Hg (mean 5). There were 2 deaths in the 30-day periprocedural period from adult respiratory distress syndrome and hepatorenal syndrome. A third patient died at 31 days from liver failure owing to continuing alcohol abuse. In addition, there was 1 case of peritoneal bleeding treated with blood product replacement. The follow-up period ranged from 14 to 671 days (mean 343). None of the patients treated for variceal bleeding had another bleeding episode, but 2 patients who had a PIPS procedure for refractory ascites did not benefit from the procedure. Postprocedure, 46% (6/13) of the patients had hepatic encephalopathy, which was unchanged from baseline. The primary and secondary patency rates at 365 days were 60% and 65%, respectively.

CONCLUSIONS

The preliminary results using a stent-graft to create an IVC-portal vein shunt are encouraging and support further work to better determine the role of this procedure.