nitinol and Hypertension--Portal

Significantly improved long-term patency can be achieved with transjugular intrahepatic portosystemic shunt (TIPS) endografts compared to conventional bare stents. In the USA, approximately 80% of TIPS procedures are performed using these devices. The phenomenon of early shunt thrombosis with TIPS created with bare stent TIPS, attributed to biliary fistulae, is seldom observed in patients with TIPS endografts. Intrashunt stenoses within the polytetrafluoroethylene-lined conduit are also rare. However, as with shunts created with bare stents, distinct patterns of dysfunction can occur with TIPS endografts. Some of these are inherent to the learning curve of placing these devices and others are secondary to device design. The interventional radiologist needs to be aware of these patterns of shunt dysfunction and have a systematic approach to their management.

Topics: Alloys; Biliary Fistula; Humans; Hypertension, Portal; Magnetic Resonance Imaging; Polytetrafluoroethylene; Portasystemic Shunt, Transjugular Intrahepatic; Portography; Prosthesis Design; Radiography, Interventional; Stents; Thrombosis; Treatment Outcome

To evaluate the safety and performance of a recently developed expanded polytetrafluoroethylene (ePTFE)-covered nitinol stent-graft to create transjugular intrahepatic portosystemic shunt (TIPS) in patients with portal hypertension and related complications.. The ePTFE-covered nitinol stent-graft was used to create TIPS in 16 patients with recurrent variceal bleeding (n = 13) or refractory ascites (n = 3). Follow-up was performed with duplex ultrasonography, clinical assessment, and venography at 6 months. Technical success and portosystemic pressure gradients (PPGs) before and after stent-graft implantation and at follow-up were assessed. Two patients died during follow-up. Histopathologic follow-up data were available for one patient at autopsy and for the other after liver transplantation.. The implantation technical success rate was 100%. Mean (+/- SD) PPG was reduced from 24 mm Hg +/- 5 to 9 mm Hg +/- 2. Histopathologic analysis of the explanted endoprostheses revealed no inflammatory response or neointima formation. The venographic follow-up data available for 10 patients demonstrated 100% in-graft patency (mean follow-up, 289 days +/- 26). Revisions with implantation of a new ePTFE-covered nitinol stent-graft or another commercially available stent in 10 patients were necessary because of hepatic vein stenosis above the grafted portion and/or relative diameter mismatch causing TIPS dysfunction.. The ePTFE-covered nitinol stent-graft was used successfully to create TIPS and has the potential to prolong TIPS patency upon complete coverage to the hepatocaval junction.

Topics: Adult; Aged; Alloys; Female; Follow-Up Studies; Humans; Hypertension, Portal; Male; Middle Aged; Polytetrafluoroethylene; Portasystemic Shunt, Transjugular Intrahepatic; Prostheses and Implants; Prosthesis Design; Stents

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

Topics: Adult; Aged; Alloys; Female; Fluoroscopy; Follow-Up Studies; Humans; Hypertension, Portal; Male; Middle Aged; Portasystemic Shunt, Transjugular Intrahepatic; Postoperative Complications; Radiology, Interventional; Retrospective Studies; Stents; Tomography, X-Ray Computed; Ultrasonography, Doppler, Color

Blakemore probe-obturator was previously preferable for primary hemostasis in patients with bleeding from esophageal varices. Currently, Danis self-expanding nitinol stent became an effective alternative. According to some manufacturers, Danis stent has some advantages over balloon tamponade. We report implantation of nitinol stent for hemostasis in a patient with multiple recurrent bleeding and ineffective endoscopic manipulations. A method of stent fixation for prevention of distal migration as the most common complication is described.. Ранее единственным методом первичного гемостаза при кровотечениях из варикозно расширенных вен пищевода являлся зонд-обтуратор Blakemore, в настоящее время появилась альтернатива в виде саморасширяющегося нитинолового стента Danis, который, по мнению производителей, обладает рядом преимуществ перед баллонной тампонадой. Рассмотрен клинический случай применения нитинолового стента с целью достижения гемостаза у пациента с многократными рецидивами кровотечений, неэффективностью эндоскопических манипуляций. Представлен метод фиксции стента с целью предотвращения самого частого осложнения установки стента — миграции в дистальном направлении и, как следствие, потери его тампонирующей функции.

Topics: Alloys; Biocompatible Materials; Esophageal and Gastric Varices; Esophagoscopy; Gastrointestinal Hemorrhage; Hemostasis, Surgical; Humans; Hypertension, Portal; Prosthesis Failure; Prosthesis Implantation; Stents

The purpose of this study was to evaluate the feasibility, safety, and efficacy of portal vein recanalization (PVR) and propose a new classification for better selecting candidates with portal vein occlusion (PVO) in whom PVR could be feasible.. The charts of 15 non-cirrhotic patients in whom stent placement using a trans-hepatic approach was attempted for the treatment of PVO with cavernous transformation were reviewed. \ There were 12 men and 3 women with a mean age of 47 ± 12 years (range: 22–60 years) [corrected].\ Intrahepatic involvement was classified into 3 groups according to the intrahepatic extent of PVO: type 1 included occlusions limited to the origin of the main portal vein and/or the right or left portal branches, type 2 included type 1 plus extension to the origin of segmental branches, type 3 included type 2 plus extension to distal branches.. There were 6 patients with PVO type 1, 7 patients with PVO type 2, and 2 patients with PVO type 3. Indications for PVR were gastrointestinal bleeding (n=6), portal biliopathy (n=2), reduce portal pressure before surgery (n=4), or other (n=3). PVR was successful in 13 patients (87%) with no severe side effects. Failure of PVR or early stent thrombosis occurred in 100% of type 3 vs. 8% of type 1 and 2 patients (P=0.03). During a mean follow-up of 42±28 months (range: 6-112 months), patients with a permeable stent had resolution of portal hypertension-related manifestations. In 13 patients in whom PVR was feasible, stent permeability was 77% at 2 years (87% vs. 60% in patients who received anticoagulation or not, respectively; P=0.3).. PVR is feasible in most patients with non-cirrhotic, non-tumoral portal vein occlusion when there is no extension of the occlusion to distal branches.

Topics: Adult; Alloys; Feasibility Studies; Female; Follow-Up Studies; Humans; Hypertension, Portal; Liver Function Tests; Male; Middle Aged; Phlebography; Portal Vein; Stents; Venous Thrombosis; Young Adult

To assess whether the use of a prosthesis covered by a Dacron sheath might prevent pseudointimal hyperplasia in a transjugular intrahepatic portosystemic shunt (TIPS).. A TIPS procedure was performed in nine pigs, after creation of a portal vein microembolization model of portal hypertension, by using a Dacron-covered nitinol stent. The first centimeter on the lower extremity of this specially made prototype was uncovered, to avoid portal vein thrombosis. Three weeks later, the seven surviving animals underwent transjugular hemodynamic and angiographic follow-up and were then killed for gross and histologic evaluation.. Shunt insertion was possible in all pigs; two died of complications of the procedure. After 3 weeks only two shunts were patent, although a 50%-60% narrowing of the initial portion of the shunt was present; the remaining shunts were occluded. Histologic examination showed pseudointimal hyperplasia associated, in the cases of occlusion, with a luminal thrombosis.. This Dacron-covered stent did not prevent pseudointima formation over the stent and resulted in a high early occlusion rate, probably related to a pronounced tissue fibrotic response likely due to Dacron-induced inflammation.

Topics: Alloys; Angiography; Animals; Disease Models, Animal; Embolism; Equipment Design; Fibrosis; Follow-Up Studies; Graft Occlusion, Vascular; Hemodynamics; Hepatic Artery; Hyperplasia; Hypertension, Portal; Polyethylene Terephthalates; Portal Vein; Portasystemic Shunt, Transjugular Intrahepatic; Stents; Surface Properties; Survival Rate; Swine; Thrombosis; Tunica Intima; Vascular Patency