Track topics on Twitter Track topics that are important to you
The transjugular intrahepatic portosystemic shunt (TIPS) is a well-established procedure for the treatment of portal hypertensive bleeding, refractory ascites and vascular diseases of the liver. The major drawbacks of this procedure are shunt dysfunction and portosystemic encephalopathy (PSE). The availability of self-expandable polytetrafluoroethylene-covered stentgrafts (PTFE-SGs) has dramatically improved the long-term patency of TIPS. However, the incidence of PSE remains a threatening complication in about 50% of patients.
The Investigators hypothesized that under-dilated PTFE-SGs would not self-expand to nominal diameter and their under-dilation would be safe and could reduce the rate of post-TIPS encephalopathy, while maintaining clinical efficacy.
Aim of this proof-of-concept exploratory study is to determine whether "under-dilated TIPS" is a feasible procedure that reduces the incidence of PSE while maintaining clinical efficacy.
The transjugular intrahepatic portosystemic shunt (TIPS) is a well-established procedure for the treatment of portal hypertensive bleeding, refractory ascites and vascular diseases of the liver. TIPS is no longer viewed solely as a salvage therapy or a bridge to liver transplantation and is currently indicated for a number of conditions related to portal hypertension with positive results regarding survival, particularly when used to treat high-risk patients with acute variceal hemorrhage. The major drawbacks of this procedure are shunt dysfunction and portosystemic encephalopathy (PSE), reported in 30-70% and 23-55% of patients with cirrhosis within the first year, respectively. The availability of self-expandable polytetrafluoroethylene-covered stent grafts (PTFE-SGs) has dramatically improved the long-term patency of TIPS. However, the incidence of PSE, that has apparently decreased with a more careful selection of patients, remains a threatening complication in about 50% of patients.
Current guidelines for TIPS placement recommend that the post-TIPS porto-caval pressure gradient (PSPG) should be reduced to less than 12 mmHg, particularly in patients with variceal hemorrhage as an indication. However, there is not enough evidence to support the use of available 10 mm rather than 8 mm nominal diameter PTFE-SG aiming to achieve this hemodynamic goal and the best control of variceal rebleeding and/or ascites. A step-wise procedure based on the progressive dilation of 10 mm diameter PTFE-SG by using balloon catheters of increasing diameter (i.e., from 8 to 10 mm) at the time of TIPS positioning has been proposed. However, if a larger diameter, leads to a higher decrease in PSPG, the higher amount of portal blood diverted to the systemic circulation and the lower residual portal perfusion of the parenchyma markedly increase the probability of post-TIPS encephalopathy.
It is conceivable that balloon dilation of TIPS to diameters smaller than those currently indicated (to 7 mm or lower) would allow for a sufficient PCG decrease in patients without a high post-TIPS portal inflow (i.e., relatively small spleen, lack of extensive portal collateralization, relatively hypodynamic circulation). However, currently no tools allow a pre-procedural definition of the ideal stentgraft diameter in individual patients. Moreover, PTFE-SGs that are specifically designed for TIPS are presently available as 8 or 10 mm and are not considered permanently under sizeable/adjustable for their intrinsic tendency to expand to nominal diameter. On the other hand, dilating PTFE-SGs far below the recommended diameter may increase the risk of TIPS thrombosis, a complication that would require prompt re-intervention.
The Investigators hypothesized that, within the cirrhotic parenchyma, under-dilated PTFE-SGs would not self-expand to nominal diameter and their under-dilation would be safe and could reduce the rate of post-TIPS encephalopathy, while maintaining clinical efficacy.
Aim Aim of this proof-of-concept exploratory study is to determine whether "under-dilated TIPS" is a feasible procedure that reduces the incidence of PSE while maintaining clinical efficacy.
Study design This study is an exploratory proof-of-concept study analyzing feasibility and clinical outcomes of under-dilated TIPS in unselected consecutive cirrhotic patients in whom TIPS is indicated clinically and who agree to participate in the study. Initially, our strategy will be to under-dilate TIPS to 7 mm in 15 patients and, if the procedure won't lead to shunt occlusion, the rest of the patients will receive a TIPS under-dilated to 6 mm.
The group with under-dilated TIPS to 7 or 6 mm will be compared to a historical control group composed of patients who had standard TIPS placed prior to initiation of the study.
TIPS placement and hemodynamic evaluation PTFE-SGs (Viatorr®, W.L. Gore & Associates Inc., Flagstaff, AZ, USA) will be placed as previously described. Semi-compliant balloon catheters will be used both to pre-dilate the intra-parenchymal tract and to dilate PTFE-SGs after deployment. The intra-parenchymal tract will be pre-dilated to 6 mm in all patients. After its deployment, the PTFE-SG will be dilated to 7 (first 15 subjects) or 6 mm (following group) in patients in whom both the procedure and the final TIPS shape will be straightforward. During dilation of the intra-parenchymal tract, balloon pressure will be maintained at the nominal value for no more than 15-30 seconds, even in the lack of a complete flattening of notches at the level of vascular walls. The intra-parenchymal tract and the PTFE-SG will be dilated to 8 mm in patients with a challenging procedure and/or in whom the final TIPS shape will be curved.
For all groups, immediately after TIPS placement, pressures in the portal vein, along the intra-parenchymal tract of TIPS, and in the inferior vena cava will be recorded until a stable tracing will be obtained in each position (45-60 seconds). Permanent tracings will be read with PowerLab computer software (ADInstruments, Inc.). Post-TIPS porto-systemic pressure gradient (PSPG) will calculated by subtracting the inferior vena cava pressure from the portal vein pressure. All procedures will be performed under monitored anesthesia care without intubation and using midazolam and fentanyl as sedative and analgesic, respectively.
PTFE-covered stent grafts
University of Florence
University of Modena and Reggio Emilia
Published on BioPortfolio: 2017-12-12T08:03:10-0500
The purpose of this prospective, randomized multicenter study is to determine whether there is any difference in stent patency of covered metallic stents in terms of stent positioning, abo...
Investigators aim to compare the efficacy of 8 mm Fluency covered stent and bare stent in transjugular intrahepatic portosystemic shunt (TIPS) for the treatment of cirrhotic portal hyperte...
Transjugular intrahepatic portosystemic shunts (TIPS) have been increasingly used for the treatment of complications of portal hypertension in patients with cirrhosis. The initial experim...
In this randomized trial two two self-expanding metal stents (SEMS) for treatment of malignant biliary strictures are investigated. A newly developed PTFE (Polytetrafluorethylen) (Teflon)...
Arteriovenous grafts are used as the vascular access in 40-50% of hemodialysis patients. Grafts are prone to recurrent stenosis (narrowing) and thrombosis (clotting). Graft clotting is us...
The iliofemoropopliteal artery significantly changes path length during normal hip and knee flexion. Prosthetic bypass grafts, such as polytetrafluroethelene (PTFE) grafts, are relatively stiff and th...
Coronary artery perforation is an infrequent, but potentially life-threatening complication of percutaneous coronary intervention. There are four types of coronary perforation: (a) large vessel; (b) d...
Fenestrated and branched endovascular aortic repair (F/B-EVAR) is associated with a high degree of technical and clinical success. Despite this, studies have also reported high reintervention rates, a...
To further optimize endoscopic stent placement, an esophageal fully covered self-expandable metal stent with through-the-scope (TTS) delivery system was designed, providing direct endoscopic control d...
The usefulness of newly modified fully covered metallic stent of 12 mm in diameter and anti-migration feature for periampullary malignant biliary strictures: comparison with conventional standard metal stent.
Fully covered self-expandable metal stent (FCSEMS) are preferred for distal malignant biliary stricture (MBS). However, stent migration is a major adverse event of FCSEMS, especially for far distal MB...
Postoperative hemorrhage from an endovascular AORTIC ANEURYSM repaired with endoluminal placement of stent grafts (BLOOD VESSEL PROSTHESIS IMPLANTATION). It is associated with pressurization, expansion, and eventual rupture of the aneurysm.
Experimentally induced chronic injuries to the parenchymal cells in the liver to achieve a model for LIVER CIRRHOSIS.
FIBROSIS of the hepatic parenchyma due to obstruction of BILE flow (CHOLESTASIS) in the intrahepatic or extrahepatic bile ducts (BILE DUCTS, INTRAHEPATIC; BILE DUCTS, EXTRAHEPATIC). Primary biliary cirrhosis involves the destruction of small intra-hepatic bile ducts and bile secretion. Secondary biliary cirrhosis is produced by prolonged obstruction of large intrahepatic or extrahepatic bile ducts from a variety of causes.
Genetic loci responsible for the encoding of histocompatibility antigens other than those encoded by the MAJOR HISTOCOMPATIBILITY COMPLEX. The antigens encoded by these genes are often responsible for graft rejection in cases where histocompatibility has been established by standard tests. The location of some of these loci on the X and Y chromosomes explains why grafts from males to females may be rejected while grafts from females to males are accepted. In the mouse roughly 30 minor histocompatibility loci have been recognized, comprising more than 500 genes.
The new and thickened layer of scar tissue that forms on a PROSTHESIS, or as a result of vessel injury especially following ANGIOPLASTY or stent placement.
Blood is a specialized bodily fluid that delivers necessary substances to the body's cells (in animals) – such as nutrients and oxygen – and transports waste products away from those same cells. In vertebrates, it is composed of blo...
Hepatology is the study of liver, gallbladder, biliary tree, and pancreas, and diseases associated with them. This includes viral hepatitis, alcohol damage, cirrhosis and cancer. As modern lifestyles change, with alcoholism and cancer becoming more promi...
Vascular relates to blood vessels (Oxford Medical Dictionary) and can be used to describe the supply of blood, a disease affecting the blood vessels or molecules associated with these structures. For example, <!--LGfEGNT2Lhm-->atherosclerosis ...