Intravascular US-guided direct intrahepatic portacaval shunt with a PTFE-covered stent-graft: feasibility study in swine and initial clinical results

Percutaneous revision of dysfunctional shunts in patients who underwent intrahepatic portosystemic shunt procedure via percutaneous or conventional method: 11-years single center experience

BACKGROUND AND AIM

Our primary objective is to report the results of the ultrasound (US)-guided revision technique of transhepatic shunt in patients in whom intrahepatic portosystemic shunt was created by the percutaneous or conventional route. Our secondary objective is to investigate whether there is an association between the indication for a portosystemic shunt and the need for post-shunt revision.

METHODS

Data from 117 consecutive patients who had a transjugular intrahepatic portosystemic shunt placed percutaneously or conventionally were extracted from hospital electronic medical records and examined those who underwent revision within 11 years and those who did not. US-guided transhepatic shunt revision technique was evaluated in terms of technical success, complications, and patency. In addition, the relationship between etiology and the need for revision was also examined using the chi-square test in three groups.

RESULTS

Forty six point two percent of patients who underwent transjugular intrahepatic portosystemic shunt required one or more revisions within 11 years. While patency of the shunt could be established via the transjugular route in 83.3% of revision patients, it was necessary to use the transhepatic route in 16.7%. The technical success rate for the US-guided transhepatic shunt revision method was 100%, and the pressure gradient between the portal and hepatic venous systems decreased below 10 mmHg in all patients at the end of the procedure.

CONCLUSION

US-guided transhepatic shunt revision is a safe and effective method where transjugular revision cannot be performed. In addition, the revision rate is significantly higher in patients who have undergone transjugular intrahepatic portosystemic shunt due to Budd-Chiari syndrome compared with other groups.

Intravascular US: Applications in Interventional Radiology

Interventional radiology applications of intravascular US (IVUS) continue to expand, complementing intraprocedural angiography and providing a unique vantage from which to guide endovascular interventions. Vascular pathologic conditions become sonographically visualized rather than inferred from the planar appearance of the opacified vascular lumen. Perivascular targets become sonographically visualized rather than approximated on the basis of fluoroscopic landmarks. The authors introduce broad categories of IVUS catheters, namely radial and side-firing varieties, as well as prevailing options for each and their technical specifications. Common applications within interventional radiology are covered in a systems approach, including deep venous thrombosis, May-Thurner syndrome, nutcracker syndrome, transjugular intrahepatic portosystemic shunts, aortic interventions, peripheral arterial disease, and endovascular or perivascular biopsy. Discussions are accompanied by technical pearls from the authors, and summarized evidence where IVUS has been shown to reduce procedural time, intravascular contrast agent dose, radiation exposure, and morbidity in each space is presented. Finally, emerging applications and future directions are discussed. ^©RSNA, 2022.

Intravascular Ultrasound Guidance for TIPS Procedures: A Review

The most challenging and time-consuming step of TIPS procedures is obtaining appropriate portal vein (PV) access. Given the lack of real-time direct target visualization, conventional fluoroscopic guidance requires multiple passes, contributing to complications. In comparison, intravascular ultrasound (IVUS) guidance during TIPS procedures provides direct visualization of hepatic structures and real-time guidance for PV puncture. IVUS guidance during TIPS creation improves procedural metrics such as radiation dose, contrast agent volume, procedure time, and technical success rate and is particularly beneficial in technically challenging cases (e.g., in patients portal vein thrombosis, small or variant portal vein anatomy, Budd-Chiari syndrome, or liver masses). The purpose of this review is to summarize current IVUS technology, describe the technical aspects of IVUS-guided TIPS creation, and discuss the clinical indications for and benefits of using IVUS for TIPS creation, while presenting available evidence supporting the technique's use. Given the improved safety profile and overall success rate in comparison with conventional guidance methods, IVUS guidance has the future potential to become the standard practice for TIPS placement.

Single Puncture TIPS—A 3D Fusion Image-Guided Transjugular Intrahepatic Portosystemic Shunt (TIPS): An Experimental Study

Background: The use of a transjugular intrahepatic portosystemic shunt (TIPS) has been established as an effective treatment for portal hypertension. Despite the rapid development of this use, serious peri-procedural complications have been reported in over 10% of cases. This has largely been attributed to the access to the portal vein, also referred to as a “blind puncture”, which often requires multiple attempts. The aim of this study was to demonstrate the safety, reproducibility and accuracy of the use of real-time 3D fusion image-guided (3DFIG) single puncture TIPS to minimize the complications that are related to the “blind puncture” of TIPS procedures. Methods: A 3DFIG TIPS approach was utilized on 22 pigs by combining pre-procedural cross-sectional imaging (CT, MR or CBCT) with intra-procedural cone beam CT or angiogram imaging, which allowed for the improved 3D visual spatial orientation of the portal vein and real-time tracking of the needle in 3D. Results: Thirty-five portosystemic shunts were successfully deployed in all 22 subjects without any peri-procedural complications. Overall, 91% (32/35) of the procedures were carried out using a single puncture. In addition, the mean fluoroscopy time in our study was more than 12 times lower than the proposed reference level that has previously been proposed for TIPS procedures. Conclusion: Multi-modality real-time 3DFIG TIPS can be performed safely using a single puncture, without complications, and can potentially be used in both emergency and non-emergency clinical situations.

Direct intrahepatic portocaval shunt (DIPS) or transjugular transcaval intrahepatic portosystemic shunt (TTIPS) to treat complications of portal hypertension: Indications, technique, and outcomes beyond Budd-Chiari syndrome

Transjugular intrahepatic portosystemic shunt (TIPS) is nowadays the benchmark treatment of severe portal hypertension complications. However, besides usual contraindication to the procedure (namely recurrent hepatic encephalopathy, severe liver dysfunction, right heart failure and/or pulmonary hypertension), TIPS appears regularly unfeasible due to abnormal and/or distorted anatomy. In this situation, the only non-surgical approaches to treat severe portal hypertension consist in the creation of an intrahepatic portocaval shunt from percutaneous (direct intrahepatic portocaval shunt - DIPS) or transjugular route (transjugular transcaval intrahepatic portosystemic shunt - TTIPS). These procedures have been rapidly adopted in patients with Budd-Chiari syndrome but are only poorly reported in patients with cirrhosis and without BCS. Considering the broadening landscape of TIPS indication in patients with cirrhosis within the last ten years, we aimed to describe the techniques, safety and efficacy of DIPS and TTIPS procedures as an alternative to TIPS in case of unfavourable anatomy.

Intravascular ultrasound for endovascular precision in pediatrics

Intravascular ultrasound (IVUS) is used as a diagnostic adjunct to angiography and has become a valuable diagnostic and interventional tool with a well-documented safety profile. The American College of Cardiology and the European Society of Cardiology have published guidelines regarding the use of IVUS in the setting of percutaneous coronary intervention. IVUS has gained popularity in the interventional radiology (IR) community in recent years; however, there are no consensus guidelines for utilization. Furthermore, IVUS remains an infrequently used modality in pediatric IR, likely because of unfamiliarity with the equipment and techniques, as well as concerns over the compatibility of these instruments with pediatric anatomy. IVUS can be safely used as a helpful and sometimes necessary tool for pediatric interventions in appropriately selected patients. The utility of IVUS for reducing both fluoroscopy time and contrast agent volume makes it particularly valuable in pediatric practice. This article presents an overview of both the rotational and phased-array IVUS types and an in-depth discussion on the most common applications of these techniques in the pediatric setting across multiple procedure categories.

Intravascular Ultrasound for the Peripheral Vasculature-Current Applications and New Horizons

Intravascular ultrasound (IVUS) is a proven and rapidly developing imaging modality that can be used for a multitude of both diagnostic and interventional purposes. By allowing for superior intraluminal characterization, compared with angiography, IVUS has emerged as a technically valuable tool in interventional procedures such as transjugular intrahepatic portosystemic shunt/direct intrahepatic portosystemic shunt, venous interventions (May Thurner stenting, inferior vena cava filter placement, recanalization in the setting of chronic venous thrombosis/insufficiency), percutaneous fenestration in the setting of aortic dissection and angioplasty. Additional applications evaluating coronary arteries and plaque morphology have been described, but are outside the scope of this review. In addition to IVUS's merit as a pre- and intra-procedural guidance modality, there are also several advantages compared to the gold standard of angiography which include decreased need for iodinated contrast, decreased radiation exposure and decreased procedural times in certain cases. With current research, such as that aimed at supraharmonic imaging, further improvements in imaging depth, resolution and contrast to noise ratio are on the horizon.

Propensity-matched comparison of transjugular intrahepatic portosystemic shunt placement techniques: Intracardiac echocardiography (ICE) versus fluoroscopic guidance

PURPOSE

To compare procedure characteristics and outcomes when TIPS is performed under intracardiac echocardiography guidance (iTIPS) compared to conventional fluoroscopic guidance (cTIPS).

MATERIALS AND METHODS

A retrospective propensity-matched study of 30 iTIPS and 30 cTIPS procedures from January 2014 to March 2017 at a single US high volume academic medical center was performed. iTIPS and cTIPS cases were propensity score matched using predictive variables: age, race, gender, etiology of liver disease, indication for TIPS, MELD score, and portal vein patency. Procedure characteristics and post- procedure outcomes were compared between propensity-matched groups including: total procedure time, technical success, radiation dose, contrast volume, complication rate, 30- day mortality, and revision rate within 3 months.

RESULTS

Radiation dose (875.3 vs 457.4 mGY, p = 0.039) and contrast volume (141 vs 103 mL, p = 0.005) were significantly decreased in the iTIPS versus the cTIPS group. There was no significant difference in procedure time (81.5 cTIPS vs 84 min iTIPS) or rate of TIPS revisions within 3 months. Average operator experience in the iTIPs group was 4.2 years and cTIPS group 11.0 years (p = 0.0004). All procedures were technically successful with no mortalities within 30 days.

CONCLUSION

iTIPS resulted in significantly reduced radiation dose and contrast volume. However, there was no difference in total procedure time or overall outcomes despite greater operator experience in the cTIPS group.

Transjugular intrahepatic portosystemic shunt creation: three-dimensional roadmap versus CO2 wedged hepatic venography

OBJECTIVES

The blind portal vein puncture remains the most challenging step during transjugular intrahepatic portosystemic shunt (TIPS) creation. We performed a prospective randomised clinical trial to compare three-dimensional (3D) roadmap with CO₂ wedged hepatic vein portography for portal vein puncture guidance.

METHODS

Between March 2017 and May 2017, 30 patients were enrolled and randomly allocated to the study group (3D roadmap) or the control group (CO₂ wedged hepatic vein portography).

RESULTS

Technical success of TIPS procedures was achieved in all 30 patients. The mean number of needle passes was significantly lower in the study group (2.0 ± 1.0) compared to the control group (3.7 ± 2.5; p = 0.021). A total of six (40%) patients in the study group and three (20%) in the control group required only one puncture for the establishment of TIPS. There were no significant differences in total fluoroscopy time (p = 0.905), total procedure time (p = 0.199) and dose-area product (p = 0.870) between the two groups.

CONCLUSIONS

3D roadmap is a safe and technically feasible means for portal vein puncture guidance during TIPS creation, equivalent in efficacy to CO₂ wedged hepatic vein portography. This technique could reduce the number of needle passes, thereby simplifying the TIPS procedure.

KEY POINTS

• 3D roadmap can be used to guide portal vein puncture. • Compared with CO ₂ venography, 3D roadmap reduced the number of needle passes. • 3D roadmap has a potential to simplify the TIPS procedure.

Real-Time 3D CT Image Guidance for Transjugular Intrahepatic Portosystemic Shunt Creation Using Preoperative CT: A Prospective Feasibility Study of 20 Patients

OBJECTIVE

The purpose of this study is to prospectively evaluate the feasibility and efficacy of real-time 3D CT image guidance during transjugular intrahepatic portosystemic shunt (TIPS) creation.

SUBJECTS AND METHODS

Between October 2013 and December 2013, a total of 20 patients were prospectively enrolled in the present study. Previously acquired portal venous phase CT datasets and intraoperative CT datasets were registered on a dedicated workstation. We accomplished semiautomatic registration for the datasets of 11 of 20 patients (55%), and we performed manual registration for the datasets of the remaining nine patients. The selected volume of interest of the CT image showing the portal vein vasculature was overlaid onto the fluoroscopic display to provide real-time 3D CT image guidance during the procedure.

RESULTS

For all 20 patients, TIPS procedures were successfully performed by the same operator. The mean (± SD) number of needle passes required for portal vein entry was 1.8 ± 1.1 passes (range, 1-5 passes). The mean duration of radiographic fluoroscopy was 3.5 ± 1.1 minutes for portal vein entry and 11.4 ± 2.1 minutes for the whole procedure. The mean radiation dose used for the whole TIPS procedure was 295.5 ± 66.6 Gy · cm². No major technical complications were observed.

CONCLUSION

Real-time 3D guidance with the use of preoperative CT is feasible, safe, and effective for assisting in the creation of TIPS. This approach may result in a shorter procedural time and less radiation exposure. However, future studies are required to compare this method with other mapping techniques.

Utility of Intravascular US-Guided Portal Vein Access during Transjugular Intrahepatic Portosystemic Shunt Creation: Retrospective Comparison with Conventional Technique in 109 Patients

PURPOSE

To compare safety and effectiveness of intravascular ultrasound (US)-guided portal vein access during transjugular intrahepatic portosystemic shunt (TIPS) creation with conventional TIPS technique.

MATERIALS AND METHODS

In this retrospective study, TIPS creation using intravascular US guidance in 55 patients was compared with conventional TIPS creation in 54 patients by 10 operators over a 3-year period. Operators were classified as experienced if they had performed ≥ 20 TIPS procedures at the beginning of the study period. Time to portal vein access, total radiation dose, and needle pass-related capsular perforation were recorded.

RESULTS

Baseline demographic characteristics of patients were similar (P > .05). Mean time to portal venous access was 46 minutes ± 37 for conventional TIPS and 31 minutes ± 19 for intravascular US-guided TIPS (P = .007). Intravascular US guidance allowed significantly shorter times (48 min ± 30 vs 28 min ± 16; P = .01) to portal vein access among operators (n = 5) with limited experience but failed to achieve any significant time savings (44 min ± 43 vs 34 min ± 22; P = .89) among experienced operators (n = 5). Needle pass-related capsular perforation occurred in 17/54 (34%) patients with conventional TIPS and 5/55 (9%) patients with intravascular US-guided TIPS (P = .004). Radiation dose was 2,376 mGy ± 1,816 for conventional TIPS and 1,592 mGy ± 1,263 for intravascular US-guided TIPS (P = .004).

CONCLUSIONS

Intravascular US-guided portal vein access during TIPS creation is associated with shorter portal vein access times, decreased needle pass-related capsular perforations, and reduced radiation dose.

Twenty-five years after the first TIPS in Spain

The incorporation, 25 years ago, of transjugular intrahepatic portosystemic shunting, better known by the acronym TIPS, represents an indisputable improvement in the treatment and management of patients with symptoms due to portal hypertension. This article discusses the origins of the technique and the technical innovations that have been progressively added through the years. The implantation of coated stents, which protect the stent from processes in the parenchymal track that can lead to stenosis, have helped ensure long-term patency, thus reducing the need for reintervention. Solid evidence from valuable publications has situated TIPS at the forefront of the treatment options in a wide variety of clinical situations associated with portal hypertension.

Novel Image Guidance Techniques for Portal Vein Targeting During Transjugular Intrahepatic Portosystemic Shunt Creation

The most challenging part of transjugular intrahepatic portosystemic shunt creation is arguably the transvenous access from the hepatic vein to the portal vein. As experience and technology have evolved, the image guidance aspect of this critical step in the procedure has become more robust. Improved means to target the portal vein include both direct and indirect methods of portal vein opacification, cross-sectional imaging for both targeting and access, and novel use of transabdominal and intravascular ultrasound guidance. These techniques are described herein.

Transjugular intrahepatic portosystemic shunt for acute variceal gastrointestinal bleeding: Indications, techniques and outcomes

Acute variceal bleeding is a life-threatening condition that requires a multidisciplinary approach for effective therapy. The transjugular intrahepatic portosystemic shunt (TIPS) procedure is a minimally invasive image-guided intervention used for secondary prevention of bleeding and as salvage therapy in acute bleeding. Emergency TIPS should be considered early in patients with refractory variceal bleeding once medical treatment and endoscopic sclerotherapy fail, before the clinical condition worsens. Furthermore, admission to specialized centers is mandatory in such a setting and regional protocols are essential to be organized effectively. This procedure involves establishment of a direct pathway between the hepatic veins and the portal veins to decompress the portal venous hypertension that is the source of the patient's bleeding. The procedure is technically challenging, especially in critically ill patients, and has a mortality of 30%-50% in the emergency setting, but has an effectiveness greater than 90% in controlling bleeding from gastro-esophageal varices. This review focuses on the role of TIPS in the setting of variceal bleeding, with emphasis on current indications and techniques for TIPS creation, TIPS clinical outcomes, and the role of adjuvant embolization of varices.

Percutaneous Portosystemic Shunts: TIPS and Beyond

Percutaneous interventions for portal hypertension have been available since the 1990s. Over time, improved technology-including covered stent grafts-and clinical understanding has expanded the available procedures for percutaneous portal decompression. While transjugular intrahepatic portosystemic shunt creation is the most commonly cited percutaneous intervention, direct intrahepatic portocaval shunt and percutaneous mesocaval shunt creation are important alternatives with specific advantages and applications. This article reviews contemporary, minimally invasive interventional approaches to percutaneous portosystemic shunt creation in terms of procedure rationale, patient selection, interventional technique, and technical outcomes.

Diagnosis and management of Budd Chiari syndrome: an update

Imaging plays a crucial role in the early detection and assessment of the extent of disease in Budd Chiari syndrome (BCS). Early diagnosis and intervention to mitigate hepatic congestion is vital to restoring hepatic function and alleviating portal hypertension. Interventional radiology serves a key role in the management of these patients. The interventionist should be knowledgeable of the clinical presentation as well as key imaging findings, which often dictate the approach to treatment. This article concisely reviews the etiology, pathophysiology, and clinical presentation of BCS and provides a detailed description of imaging and treatment options, particularly interventional management.

Intravascular ultrasound for transvenous interventions

Since the development of intravascular ultrasound in the late 1980s, the modality has been used both to image the vascular system and to direct interventions in target vessels. Intravascular ultrasound (IVUS) was initially used to image atherosclerosis and aid in its treatment, but it has more recently been employed within the venous system, allowing for both intravenous and transvenous image-guided interventions. IVUS is now used for both direct and transjugular intrahepatic portosystemic shunt placement, for transcaval liver biopsy and transcaval puncture of type II endoleaks, and for cardiac mass biopsy, among other interventions. The use of IVUS not only yields potential for reduced fluoroscopy dose in and increased safety of established procedures, but it also allows for the development of altogether new procedures.

The transjugular intrahepatic portosystemic shunt: an update

OBJECTIVE

The purpose of this article is to review the indications, outcomes, complications, patient selection, and technical aspects of creating a transjugular intrahepatic portosystemic shunt (TIPS).

CONCLUSION

The best available evidence supports the use of TIPS in secondary prevention of variceal bleeding and in refractory ascites, although TIPS is also commonly used for other indications such as Budd-Chiari syndrome, hepatic hydrothorax, and acute variceal hemorrhage. The TIPS procedure was revolutionized by the introduction of covered stents, which dramatically improved long-term shunt patency.

Transjugular intrahepatic portosystemic shunt creation using intravascular ultrasound guidance

PURPOSE

To describe the use of intravascular ultrasound (US) guidance for creation of transjugular intrahepatic portosystemic shunts (TIPSs) in humans.

MATERIALS AND METHODS

The initial 25 cases of intravascular US-guided TIPS were retrospectively compared versus the last 75 conventional TIPS cases during the same time period at the same institution in terms of the number of needle passes required to establish portal vein (PV) access, fluoroscopy time, and needle pass-related complications.

RESULTS

Intravascular US-guided TIPS creation was successful in all cases, and there was no statistically significant difference in number of needle passes, fluoroscopy time, or needle pass-related complications between TIPS techniques. Intravascular US-guided TIPS creation was successful in cases in which conventional TIPS creation had failed as a result of PV thrombosis or distorted anatomy. Intravascular US guidance for TIPS creation was additionally useful in a patient with Budd-Chiari syndrome and in a patient with intrahepatic tumors.

CONCLUSIONS

Intravascular US is a safe and reproducible means of real-time image guidance for TIPS creation, equivalent in efficacy to conventional fluoroscopic guidance. Real-time sonographic guidance with intravascular US may prove advantageous for cases in which there is PV thrombus, distorted anatomy, Budd-Chiari syndrome, or hepatic tumors.

Ultrasound-guided transhepatic puncture of the hepatic veins for TIPS placement

PURPOSE

This retrospective analysis was carried out to assess the feasibility and results of transjugular intrahepatic portal systemic shunt (TIPS) performed with ultrasound (US)-guided percutaneous puncture of the hepatic veins.

MATERIAL AND METHODS

Over a period of 3 years, 153 patients were treated with TIPS at our centre. In eight cases, a percutaneous puncture of the middle (n=7) or right (n=1) hepatic vein was required because the hepatic vein ostium was not accessible. Indications for TIPS were bleeding (n=1), Budd-Chiari syndrome (n=1), ascites (n=2), reduced portal flow (n=1) and incomplete portal thrombosis (n=3). A 0.018-in. guidewire was anterogradely introduced into the hepatic vein to the inferior vena cava (IVC) through a 21-gauge needle. In the meantime, a 25-mm snare-loop catheter was introduced through the jugular access to retrieve the guidewire, achieving through-andthrough access. Then, a Rosch-Uchida set was used to place the TIPS with the traditional technique.

RESULTS

Technical success was achieved in all patients. There was one case of stent thrombosis. One patient died of pulmonary oedema. Three patients were eligible for liver transplantation, whereas the others were excluded due to shunt thrombosis (n=1) and previous nonhepatic neoplasms (n=3).

CONCLUSIONS

The percutaneous approach to hepatic veins is rapid and safe and may be useful for avoiding traumatic liver injuries.

Technical note: Reduction of radiation dose using ultrasound guidance during transjugular intrahepatic portosystemic shunt procedure

The transjugular intrahepatic portosystemic shunt (TIPS) procedure for decompression of the portal venous system generally performed under fluoroscopic guidance has undergone continuous technical modifications recently. Due to the length of the procedure, the fluoroscopy times are reasonably high, thus increasing the risk from ionizing radiation. Radiation doses were measured for 19 patients using dose area product (DAP) meter. The average DAP value for the TIPS procedure was 63.86 Gy cm(2) (21.12-117.07). Radiation doses to patients can be reduced with the use of USG guidance and intermittent fluoroscopy screening.

The difficult transjugular intrahepatic portosystemic shunt: alternative techniques and "tips" to successful shunt creation

The transjugular intrahepatic portosystemic shunt (TIPS) is one of the most complex procedures performed by interventional radiologists. Most of these procedures are straightforward and may be successfully completed within 2 hours. In some cases, TIPS creation may be extremely difficult, for example in situations such as: variant anatomy, portal vein thrombosis, hepatic vein thrombosis, or preexisting TIPS. In this article we describe some maneuvers that may be attempted in cases where creation of the shunt proves to be difficult.

Patency and clinical outcomes of transjugular intrahepatic portosystemic shunt with polytetrafluoroethylene-covered stents versus bare stents: a meta-analysis

BACKGROUND AND AIM

 Transjugular intrahepatic portosystemic shunt (TIPS) with polytetrafluoroethylene-(PTFE)-covered stent has been increasingly used for patients with complications of portal hypertension. It is still debated whether the new endoprostheses will improve some clinical outcomes (except for shunt patency) compared to the bare stents. The aims of our meta-analysis were to explore the patency and clinical outcomes of TIPS with PTFE-covered stent-grafts versus bare stents.

METHODS

Pertinent studies were retrieved through PubMed (1950-2010), MEDLINE (1950-2010), and reference lists of key articles. Outcome measures were primary patency, risk of encephalopathy and survival. Time-to-event data analysis was used to calculate the overall hazard ratios (HR).

RESULTS

Six studies were identified including a total of 1275 patients (346 TIPS with PTFE-covered stent-grafts and 929 TIPS with bare stents). Pooled shunt patency data from four eligible studies suggested a significant improvement of primary patency in patients who were treated with PTFE-covered stent-grafts (HR = 0.28, 95% confidence interval [CI] 0.20-0.35). Pooled encephalopathy data from three eligible studies suggested a significant reduction of risk in the PTFE-covered group (HR = 0.65, 95%CI 0.45-0.86). Pooled survival data from four eligible studies also suggested a significant decrease of mortality in the PTFE-covered group (HR = 0.76, 95%CI 0.58-0.94). No statistical heterogeneity was observed between studies for either outcome.

CONCLUSIONS

This meta-analysis shows that the use of PTFE-covered stent-grafts clearly improves shunt patency without increasing the risk of hepatic encephalopathy and with a trend towards better survival.

New coaxial transseptal needle for creation of atrial septal defects in adult sheep

OBJECTIVES

To introduce a new transseptal (TS) needle assembled in our laboratory--the coaxial TS (CTS) needle--and describe our experience with it in creating experimental atrial septal defects (ASD) in adult sheep.

BACKGROUND

With commercially available TS needles, we were not able to consistently perform TS puncture at the fossa ovalis in adult sheep.

MATERIAL AND METHODS

Ten adult sheep with a mean weight of 63.5 kg were used. The CTS needle consists of four components: a 9F Teflon catheter, a 14-gauge blunt curved-tip metal cannula, a 4F tapered catheter, and a 20-gauge open needle. A transjugular 5F pigtail catheter was used to display the septal anatomy by angiocardiography and was left in place to mark the level of the fossa ovalis. The septum was then probed by a transfemoral 5F curved-tip end-hole catheter. The CTS needle was aligned with the tip of the transjugular catheter, and the TS puncture was performed under fluoroscopic guidance. After documenting a left atrial position, a balloon angioplasty catheter was used for creation of the ASD.

RESULTS

A small patent foramen ovale was discovered by septal probing in one sheep. All sheep underwent successful TS punctures without complications. The ASD size ranged from 13 to 15 mm. In eight sheep, the ASD was in fossa ovalis. In the first two sheep where the needle was not well aligned with the marking catheter, the ASD was in the septum secundum. No damage to the atrial or other heart structures was found at necropsy.

CONCLUSION

The CTS needle is a suitable needle for TS puncture and ASD creation in adult sheep. Proper alignment of the CTS needle with a catheter marking the fossa ovalis is essential for successful puncture.

Transjugular intrahepatic portocaval shunt placed through the strut of an inferior vena cava stent in a patient with Budd-Chiari syndrome: a technical modification

Transjugular intrahepatic portocaval shunt (TIPS) is performed in patients with symptomatic Budd-Chiari syndrome (BCS) who do not have repairable hepatic veins. We report the case of a patient who had an inferior vena cava (IVC) stent placed previously as part of the management for BCS, and who subsequently required TIPS. The TIPS tract was created through the strut of the previously placed IVC stent; the TIPS stent was placed after dilatation of the liver parenchyma as well as the strut of the IVC stent. This novel technique of "strutplasty" of a previously placed stent as part of TIPS has not been reported in the literature.

Direct intrahepatic portocaval shunt

The direct intrahepatic portacaval shunt (DIPS) is a modification of the TIPS procedure, using intravascular ultrasound-guidance, combined with fluoroscopy. The DIPS procedure was initially conceived to increase the durability of shunt patency and extend the spectrum of patients with portal hypertension for whom endovascular portocaval shunting can be performed. The DIPS procedure involves intravascular ultrasound-guided puncture from the inferior vena cava to the portal vein through the caudate lobe of the liver. The shunt is completed with a polytetrafluoroethylene-covered stent graft. This article describes the indications, technique, and outcomes of the DIPS procedure to enable the interventional radiologist currently experienced with TIPS to incorporate this procedure into their practice.

Direct intrahepatic portocaval shunt through transhepatic puncture via retrohepatic inferior vena cava: applied anatomical study

BACKGROUND

DIPS is to create a portosystemic shunt directly between the portal vein and the retrohepatic inferior vena cava (RIVC) without passing through the hepatic vein. It has been recommended that the DIPS could be applied when routine TIPS is unsuccessful or the patient has anatomical variations of the hepatic vein. The aim of this study was to identify the safe area of the RIVC where the DIPS can be safely established.

MATERIALS AND METHODS

The lengths of the safe and unsafe areas of the RIVC were measured. The tributaries of the RIVC were examined. The diameter of these tributaries was measured and their incidence and relation to the safe area of the RIVC were observed. The puncture distances of DIPS and TIPS were measured and compared.

RESULTS

The liver together with the RIVC was collected from 31 adult cadavers (age 32-65 years; M/F 25/6). 1. The safe and unsafe areas of the RIVC: the total length of the RIVC was 70.1 +/- 13.0 mm (33.1-92.0 mm), whereas the length of the safe area of the RIVC was 54.3 +/- 12.3 mm (20.2-71.1 mm), which was about over 70% of the total length. The length of the unsafe area at the upper end was 5.9 +/- 1.8 mm (3.0-10.2 mm), and at the lower end was 8.9 +/- 2.9 mm (3.1-20.0 mm). 2. The tributaries of the RIVC: In about 90% of the cadavers (90.3%; 28 out of 31), the LHV and MHV had the common trunk. The other three cadavers (9.7%; 3 out of 31) had independent RHV, MHV and LHV. There were 217 of small hepatic veins draining into the lower segment of the RIVC. Over 70% of the small hepatic veins were smaller than 5 mm in diameter and distributed on the anterior and left wall of the lower RIVC. 3. Puncture distances of the DIPS and TIPS: The distances from the bifurcation of the portal vein to the RIVC, to the right and to middle hepatic veins were 31.2 +/- 7.9 mm (15.0-47.2 mm), 38.6 +/- 8.1 mm (17.2-59.0 mm), and 46.6 +/- 8.2 mm (34.0-68.1 mm), respectively. Thus, the puncture distances via the RIVC, RHV and LHV were significantly different (P < 0.001). The puncture distance of the DIPS was shortest.

CONCLUSION

Anatomically, DIPS is a feasible interventional procedure to make a intrahepatic shunt between IVC and portal vein directly, and has its anatomical advantages compared to TIPS.

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.

Transjugular Intrahepatic Portosystemic Shunt Creation in Budd-Chiari Syndrome: Percutaneous Ultrasound-Guided Direct Simultaneous Puncture of the Portal Vein and Vena Cava

Budd-Chiari syndrome (BCS) is an uncommon disorder that can be life-threatening, depending on the degree of hepatic venous outflow obstruction. Transjugular intrahepatic portosystemic shunt (TIPS) provides decompression of the congested liver but the hepatic vein obstruction makes the procedure more difficult. We describe a modified method that involved a single percutaneous puncture of the portal vein and inferior vena cava simultaneously for TIPS creation in a patient with BCS.

Transjugular intrahepatic portosystemic shunt--role in treating intractable variceal bleeding, ascites, and hepatic hydrothorax

Transjugular intrahepatic portosystemic shunt (TIPS) patency can be improved by the use of covered stents. Although this technical advance may lower the costs associated with TIPS, the overall role of TIPS in the management of portal hypertension may not change. Currently, bare metal TIPS is indicated in the treatment of acute refractory variceal hemorrhage, in the secondary prevention of variceal hemorrhage, for the management of ascites refractory to both medical management and large-volume paracentesis, and in the control of hepatic hydrothorax refractory to medical management.

Evaluation of MR/Fluoroscopy–guided Portosystemic Shunt Creation in a Swine Model

PURPOSE

To evaluate three different percutaneous portosystemic shunts created with magnetic resonance (MR) imaging and fluoroscopy guidance in a swine model.

MATERIALS AND METHODS

In stage 1 of the experiment, an active MR intravascular needle system was created for needle tracking and extracaval punctures. Twenty inferior vena cava (IVC)/superior mesenteric vein (SMV)/portal vein (PV) punctures were performed in 10 swine (weight, 40-45 kg) in a 1.5-T short-bore interventional MR imager. With use of a real-time MR imaging sequence, the needle was guided through the IVC and into the SMV or PV (N = 20 punctures). After confirmation, a wire was advanced into the portal venous system under MR imaging guidance (N = 20). In stage 2, animals were transferred to the radiographic fluoroscopy suite for deployment of shunts. Three different shunts were evaluated in this study: (i) a commercial stent-graft, (ii) a prototype bridging stent, and (iii) a prototype nitinol vascular anastomotic device. Postprocedural necropsy was performed in all animals.

RESULTS

Successful MR-guided IVC/SMV punctures were performed in all 20 procedures (100%). All three shunts were deployed. Stent-grafts had the poorest mechanism for securing a shunt. The vascular anastomotic device and the bridging stent had more secure anchoring mechanisms but also had higher technical failure rates (50% and 40%, respectively). When deployed successfully, the vascular anastomotic device resulted in no bleeding at the sites of punctures at necropsy.

CONCLUSION

Percutaneous shunts and vascular anastomoses between the portal mesenteric venous system and IVC were successfully created with use of a combination of MR imaging and conventional fluoroscopy for guidance.

Treatment of Tracheobronchial Obstruction with a Polytetrafluoroethylene-covered Retrievable Expandable Nitinol Stent

PURPOSE

To evaluate the clinical effectiveness of polytetrafluoroethylene (PTFE)-covered retrievable expandable nitinol stents in tracheobronchial strictures.

MATERIALS AND METHODS

With fluoroscopic guidance, PTFE-covered retrievable expandable nitinol stents were placed in 15 symptomatic patients with benign (n = 6) or malignant (n = 9) tracheobronchial strictures. Complications and improvement in respiratory status were evaluated. Stents were removed electively 6 months after placement in benign strictures or if complications occurred. Membrane degradation or separation from the wire mesh was evaluated in removed stents.

RESULTS

A total of 17 stents were successfully placed and were well tolerated in all patients. Sputum retention, stent migration, and tissue hyperplasia occurred in 23.5% (n = 4), 17.6% (n = 3), and 17.6% (n = 3) of stents, respectively. A total of 11 stents were successfully removed electively 6 months after placement (n = 4) or when complications occurred (n = 7). All 11 such stents were removed without difficulty with use of standard techniques, antecedent balloon dilation being necessary in two cases as a result of tissue hyperplasia. No removed stent showed signs of membrane degradation, and two removed stents showed signs of membrane separation from the mesh.

CONCLUSIONS

PTFE-covered retrievable expandable nitinol stents were effective in the treatment of tracheobronchial strictures. Stent removal was easy with use of standard techniques, and no removed stent showed evidence of membrane degradation.

Interventional procedures involving portal vein circulation: a review

Rapid development of diagnostic radiological methods during recent decades has been followed by development of new interventional procedures involving portal circulation. The majority of these interventions were developed for treatment of patients with symptoms secondary to portal hypertension (PH). Interventions involving portal vein circulation have an established position in the treatment of PH and other diseases, and further development of these methods can be expected.

Experimental Percutaneous Extrahepatic Portacaval Shunt Creation by Transjugular Approach in Swine

The purpose of the study was to evaluate the feasibility of the creation of a percutaneous extrahepatic portacaval shunt (PEPS) in swine by a transjugular approach and to find a suitable stent-graft to use in PEPS. In 12 swine, the extrahepatic portal vein (PV) was entered from the inferior vena cava (IVC) by a needle system introduced from the transjugular approach. A catheter introduced through the transhepatic approach served as a target. Five types of stent-graft consisting of homemade Z stents and a polytetrafluoethylene cover were explored for PEPS creation. Eight animals had follow-up venograms up to 6 weeks or until the shunt became severely stenotic. Gross and histologic examinations were performed after the final follow-up venography. The PV punctures and stent-graft placement were difficult, but the PEPS was established in all animals. In four animals, the stent-graft failed to adequately cover the tract, causing severe hemorrhage. Only two shunts remained patent up to 6 weeks. The other shunts exhibited severe stenosis or occlusion. At gross examination, all shunts traversed the liver parenchyma of the caudate lobe surrounding the IVC. The extravascular PEPS portion was 4 mm to 2 cm long. All shunts entered the PV close to the splenomesenteric junction and exhibited neointimal formation. Shunt stenoses were caused by neointimal hyperplasia and occlusions by a superimposed thrombus. PEPS can be created by the transjugular approach in swine, but only the PV shunt entrance is extrahepatic. None of the tested rigid stent-grafts were suitable for PEPS creation. A short flexible stent-graft with flanged ends is suggested for further exploration.

A flexible stent with small intestinal submucosa covering for direct intrahepatic portocaval shunt: experimental pilot study in swine

The suitability of the flexible sandwich Zilver stent-graft (SZSG) with a biologically active tissue layer (small intestinal submucosa) for creation of the intravascular ultrasound (IVUS)-guided direct intrahepatic portocaval shunt (DIPS) was explored in six young swine in a search for a flexible system to replace the rigid polytetrafluoroethylene (PTFE) stent originally used by this group with limited success. The portal vein was punctured from the inferior vena cava through the caudate lobe of the liver using IVUS guidance. After balloon dilation of the puncture tract, DIPS was successfully created in all animals with use of an SZSG 9 mm in diameter and 6 cm or 8 cm long. Only one DIPS remained well patent at 14 days when the animal had to be killed because of encephalopathy. DIPS in the other five animals were found to be either severely stenosed (3 animals) or occluded (2 animals) at 4 weeks due to accelerated formation of neointimal hyperplasia (NIH) in the liver parenchymal portion of the shunt and superimposed thrombosis. The lack of high pressure in the portal system contributed to early endograft closure. The flexible stent and the covering fail badly. The reason for this could be due to either component. More work is required to find a reliable flexible system with long-term patency. Exploration of the IVUS-guided direct extrahepatic portocaval shunt is suggested.

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.

Percutaneous Extrahepatic Portacaval Shunt with Covered Prostheses: Feasibility Study

PURPOSE

To assess the anatomic feasibility of creating a percutaneous extrahepatic portosystemic shunt (PEPS) between the main portal vein (MPV) and the inferior vena cava (IVC) in patients with cirrhosis and to evaluate the feasibility of this approach in an animal model.

MATERIALS AND METHODS

In human studies, computed tomographic (CT) scans from 34 patients with cirrhosis were reviewed to assess the distance and anatomic structures found between the MPV and IVC. The MPV was divided into upper, middle, and lower thirds for analysis. In the experimental model, PEPS were created in 10 beagle dogs by placing between the MPV and IVC a tubular polyurethane-covered prosthesis with flared ends designed for this study. Different approaches, devices, and prostheses were assayed.

RESULTS

In human studies, the shortest mean distance between the IVC and the MPV was found in the lower third of the MPV (1.18 cm +/- 0.6). The lower third, the nearest to the confluence of splenic and superior mesenteric veins, also presented fewer intervening structures, and the spatial relationship between the veins at this level was predictable. In the experimental model, direct portography was performed, with a small mesenteric vein catheterized through a minilaparotomy and a transjugular access to the IVC. A needle was advanced from the MPV to the IVC, and a polyurethane cone-shaped covered prosthesis was placed to bridge the path between the veins. Six of 10 animals died from bleeding that occurred either because several punctures were made during the procedure or because the prosthesis became dislodged when the mesentery was moved before suturing the minilaparotomy. The remaining four were kept alive for 1, 5, 60, and 90 days after the procedure.

CONCLUSIONS

PEPS creation in patients with cirrhosis is anatomically possible. The lower third of the MPV should be the most suitable level at which to create the shunt. Preliminary studies carried out in beagle dogs support the feasibility of this approach. However, further work is needed to improve the efficacy of this technique.

Transvenous extrahepatic portacaval shunt: feasibility study in a Swine model

PURPOSE

To evaluate the feasibility of intravascular ultrasonography (US)-guided access to the extrahepatic segment of the main portal vein (PV) to create a transvenous extrahepatic portacaval shunt (TEPS) as an easier and more durable alternative to transjugular intrahepatic portosystemic shunt.

MATERIALS AND METHODS

PV access from the inferior vena cava (IVC) to the main PV was performed in eight pigs by using intravascular US guidance. Either a prototype stent-graft (n = 6) or Wallgraft (n = 2) was used to create the shunt. Intravascular US demonstrated the main PV to be in direct contact with the IVC in all animals. A mean of 1.75 needle passes were needed to enter the PV. Immediate postprocedure computed tomography (CT) of the abdomen helped identify and quantify the presence of hemoperitoneum. Shunt venography was performed at 2 weeks, followed by necropsy.

RESULTS

PV access and TEPS creation were successful in all animals. Contrast medium extravasation, due to inadequate coverage of the portacaval tract, was identified in four procedures and addressed by the placement of additional devices in three cases and prolonged balloon inflation in one. Abdominal CT demonstrated small amounts of hemoperitoneum in five animals and moderate to large amounts in three. Two animals did not live to the 2-week follow-up study. One animal was sacrificed on the day of the procedure owing to intraperitoneal hemorrhage; the second died of intussusception-related bowel necrosis 10 days after TEPS creation. Shunts were occluded or severely stenotic at venography and necropsy in the remaining six animals.

CONCLUSION

TEPS is technically feasible after intravascular US-guided PV access.

Direct intrahepatic portacaval shunt: An experimental study

AIM: To determine the feasibility of creating direct intrahepatic portacaval shunt (DIPS) in swine with puncture under sonographic guidance.

METHODS: DIPS was created in 10 domestic swine under sonographic guidance. Liver function, blood ammonia level and portosystemic gradient (PSG) were compared before and after the procedure. Patency of shunt was followed by portography every 7 d after DIPS.

RESULTS: DIPS was successfully established in all 10 swine without any complications. One day after procedure the alanine aminotransferase (ALT), aspartate aminotransferase (AST), and blood ammonia level (BAL) of swine rose from 5.40 ± 0.69, 16.00 ± 0.79 and 35.66 ± 4.10 to 34.20 ± 3.46, 59.70 ± 2.22 and 66.94 ± 3.44 respectively (P < 0.05). The PSG decreased from 0.59 ± 0.20 kPa to 0.24 ± 0.11 kPa after DIPS (P < 0.05). The shunt of 10 swine was kept patent from 7-28 d (median patency time was 14 d).

CONCLUSION: This initial experience demonstrated that creating intrahepatic portacaval shunt from retrohepatic segment of IVC to portal vein with puncture under sonographic guidance in swine is safe and feasible. Further studies are necessary to perform DIPS in cirrhosis patients.

Main portal vein access in transjugular intrahepatic portosystemic shunt procedures: use of three-dimensional ultrasound to ensure safety

PURPOSE

To document the safety of main portal vein (PV) access to create transjugular portosystemic intrahepatic shunts (TIPS), provided that three-dimensional ultrasonography (3D US) can document the puncture to have entered a surface of the PV suitable for tamponade.

MATERIALS AND METHODS

In 11 patients who underwent conventional TIPS creation (n = 10) or a transjugular portacaval shunt procedure (n = 1), the puncture was found angiographically to enter the main PV. In seven cases, this occurred at the PV bifurcation and, in four, it occurred in the superior third of the PV. 3D US was used to determine whether the point of PV entry was functionally intrahepatic or extrahepatic. The puncture site was deemed to be intrahepatic if liver covered the puncture site on all three orthogonal imaging planes (sagittal, coronal, and transverse). If the puncture site was surrounded by liver, the access was used to deploy a metallic stent (uncovered, n = 10; covered, n = 1). Medical records and follow-up cross-sectional imaging studies were reviewed for evidence of hemorrhage complications. Pathologic correlation was performed in one explanted liver and autopsy specimens in five other patients.

RESULTS

In nine of 11 patients, 3D US was diagnostic and confidently verified that liver completely covered the portal vein access site. In two patients with diagnostically uncertain 3D US results, transcatheter injection of contrast medium documented no extravasation. All TIPS and direct portacaval shunt procedures were technically successful. No hemorrhagic complications occurred. Examination of pathologic specimens documented this portion of the portal vein to be extraperitoneal, but attached to the superior surface of the caudate lobe with fibrous tissue and small portal vein branches.

CONCLUSIONS

The bifurcation and posterior aspect of the superior third of the main PV can be safely used for TIPS procedures, provided access is proven to be surrounded by liver. 3D US can usually confidently determine if the PV entry site is functionally intrahepatic.