Efficacy of a Paclitaxel-Eluting Nitinol Stent on the Inhibition of Pseudointimal Hyperplasia in a Transjugular Intrahepatic Portosystemic Shunt: An Experimental Study in a Swine Model

PURPOSE: To evaluate the efficacy of a paclitaxel-eluting nitinol stent on the inhibition of pseudointimal hyperplasia in a transjugular intrahepatic portosystemic shunt. MATERIALS AND METHODS: Twelve pigs were used in this study. Two types of 10-mm diameter and 60-mm long nitinol stents were made for a transjugular intrahepatic portosystemic shunt by coating them with a polyurethane solution, with and without paclitaxel. Each transjugular intrahepatic portosystemic shunt was created successfully in the 12 swine with 7 paclitaxel-eluting stents and 5 polyurethane stents. Five swine in each group were followed-up for 14 days due to the death of 2 swine given the paclitaxel-eluting stents. The proliferation of the pseudointima was evaluated on both follow-up portograms and histopathology examinations. The mean maximum pseudointimal hyperplasia is expressed as the percentage of the stent radius. RESULTS: On the portograms, all the transjugular intrahepatic portosystemic shunts using the paclitaxel-eluting stents maintained patency despite there being a complete occlusion of the polyurethane stents in all the animals. The histopathology analysis revealed the mean maximum pseudointimal hyperplasia to be 25% and 76% in the paclitaxel-eluting and control stents, respectively. CONCLUSION: A transjugular intrahepatic portosystemic shunt with a paclitaxel-eluting nitinol stent appears to significantly inhibit the formation of pseudointimal hyperplasia.

Efficacy of a Dexamethasone-Eluting Nitinol Stent on the Inhibition of Pseudointimal Hyperplasia in a Transjugular Intrahepatic Portosystemic Shunt: An Experimental Study in a Swine Model

OBJECTIVE: We wanted to evaluate the feasibility and efficacy of using a dexamethasone (DM) -eluting nitinol stent to inhibit the pseudointimal hyperplasia following stent placement in the transjugular intrahepatic portosystemic shunt tract (TIPS) of a swine. MATERIALS AND METHODS: Fifteen stents were constructed using 0.15 mm-thick nitinol wire; they were 60 mm in length and 10 mm in diameter. The metallic stents were then classified into three types; type 1 and 2 was coated with the mixture of 12% and 20%, respectively, of DM solution and polyurethane (PU), while type 3 was a bare stent that was used for control study. In fifteen swine, each type of stent was implanted in the TIPS tract of 5 swine, and each animal was sacrificed 2 weeks after TIPS creation. The proliferation of the pseudointima was evaluated both on follow-up portogram and pathologic examination. RESULTS: One TIPS case, using the type 1 stent, and two TIPS cases, using the type 2 stent, maintained their luminal patency while the others were all occluded. On the histopathologic analysis, the mean of the maximum pseudointimal hyperplasia was expressed as the percentage of the stent radius that was patent, and these values were 51.2%, 50% and 76% for the type 1, 2, and 3 stents, respectively. CONCLUSION: The DM-eluting stent showed a tendency to reduce the development of pseudointimal hyperplasia in the TIPS tract of a swine model with induced-portal hypertension.

Prevention of Potential Complications Related to Transjugular Intrahepatic Portosystemic Shunt Procedure: Efficacy of Polytetrafluoroethylene Stent Grfat

PURPOSE: The purpose of this study was to assess the efficacy of a polytetrafluoroethylene (PTFE) stent graft for preventing potential complications related to a transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: Between January 2002 and March 2003, seven patients (males: 5, females: 2, mean age: 44) underwent TIPS stent placement using the PTFE stent graft (Nitis, Taewoong, Seoul, Korea) to prevent potential complications such as life threatening hemoperitoneum, hemobilia and early stent occlusion. Three patients were admitted for esophageal varix bleeding, three patients were admitted for gastric varix bleeding and one patient was admitted for umbilical bleeding. The extrahepatic portal vein was punctured inadvertently in four patients (main portal vein: 1 case, portal vein bifurcation: 3 cases), but contrast media extravasation into the peritoneal cavity on the tractogram was noted only in two patients. Two of four patients had chronic portal vein occlusion with intra- and extrahepatic cavernous transformation. The bile duct was inadvertently punctured and visualized on the tractogram in three patients. RESULTS:All the identified biliary trees or contrast media extravasations observed on the tractograms were successfully sealed off on the post-procedure portograms. The immediate post-procedure clinical recovery courses were uneventful in all patients (no hemobilia or hemoperitoneum was noted). Bleeding control was successful in all patients. The one patient who had Child-Pugh class C disease died of hepatic encephalopathy 3 days after TIPS placement. Five of the six living patients have not shown any complications or rebleeding during the follow up periods (9-23 months). The one patient who had biliary communication on the tractogram re-bled due to TIPS stent stenosis 25 days after TIPS, and this patient was successfully treated by TIPS revision. CONCLUSION: Potential complications related to TIPS procedure can be successfully prevented with PTFE stent-graft placement.

Standardization of MIP Technique in Three-dimensional CT Portography: Usefulness in Evaluation of Portosystemic Collaterals in Cirrhotic Patients

PURPOSE: To assess the usefulness of three-dimensional CT portography using a standardized maximum intensity projection (MIP) technique for the evaluation of portosystemic collaterals in cirrhotic patients. MATERIALS AND METHODS: In 25 cirrhotic patients with portosystemic collaterals, three-phase CT using a multidetector-row helical CT scanner was performed to evaluate liver disease. Late arterial-phase images were transferred to an Advantage Windows 3.1 workstation (Gener Electric). Axial images were reconstructed by means of three-dimensional CT portography, using both a standardized and a non-standardized MIP technique, and the respective reconstruction times were determined. Three-dimensional CT portography with the standardized technique involved eight planes, namely the spleno-portal confluence axis (coronal, lordotic coronal, lordotic coronal RAO 30 degree, and lordotic coronal LAO 30 degree), the left renal vein axis (lordotic coronal), and axial MIP images (lower esophagus level, gastric fundus level and splenic hilum). The eight MIP images obtained in each case were interpreted by two radiologists, who reached a consensus in their evaluation. The portosystemic collaterals evaluated were as follows: left gastric vein dilatation; esophageal, paraesophageal, gastric, and splenic varix; paraumbilical vein dilatation; gastro-renal, spleno-renal, and gastrospleno-renal shunt; mesenteric, retroperitoneal, and omental collaterals. RESULTS: The average reconstruction time using the non-standardized MIP technique was 11 minutes 23 seconds, and with the standardized technique, the time was 6 minutes 5 seconds. Three-dimensional CT portography with the standardized technique demonstrated left gastric vein dilatation (n=25), esophageal varix (n=18), paraesophageal varix (n=13), gastric varix (n=4), splenic varix (n=4), paraumbilical vein dilatation (n=4), gastro-renal shunt (n=3), spleno-renal shunt (n=3), and gastro-spleno-renal shunt (n=1). Using three-dimensional CT portography and the non-standardized MIP technique, the portosystemic collaterals demonstrated were similar to those demonstrated using the standardized technique. Additionally, howerer, the former revealed features not revealed by the latter, namely splenic varix (n=1), mesenteric collaterals (n=4), retroperitoneal collaterals (n=3), and omental collaterals (n=2). CONCLUSION: In patients with liver desease, three-dimensional CT portography using a standardized of MIP technique helps evaluate portosystemic collaterals, reduces interobserver bias, and saves reconstruction time.

Transcaval Transjugular Intrahepatic Portosystemic Shunt: Preliminary Clinical Results

OBJECTIVE: To determine the feasibility of transcaval transjugular intrahepatic portosystemic shunt (TIPS) creation in patients with unusual anatomy between the hepatic veins and portal bifurcation, and inaccessible or inadequate hepatic veins. MATERIALS AND METHODS: Transcaval TIPS, performed in six patients, was indicated by active variceal bleeding (n=2), recurrent variceal bleeding (n=2), intractable ascites (n=1), and as a bridge to liver transplantation (n=1). The main reasons for transcaval rather than classic TIPS were the presence of an unusually acute angle between the hepatic veins and the level of the portal bifurcation (n=3), hepatic venous occlusion (n=2), and inadequate small hepatic veins (n=1). RESULTS: Technical and functional success was achieved in all patients. The entry site into liver parenchyma from the inferior vena cava was within 2 cm of the atriocaval junction. Procedure-related complications included the death of one patient due to hemoperitoneum despite the absence of contrast media spillage at tractography, and another suffered reversible hepatic encephalopathy. CONCLUSION: In patients with unusual anatomy between the hepatic veins and portal bifurcation, and inaccessible or inadequate hepatic veins, transcaval TIPS creation is feasible.

Transcaval TIPS in Patients with Failed Revision of Occluded Previous TIPS

OBJECTIVE: To determine the feasibility of transcaval transjugular intrahepatic portosystemic shunt (TIPS) in patients with occluded previous TIPS. MATERIALS AND METHODS: Between February 1996 and December 2000 we performed five transcaval TIPS procedures in four patients with recurrent gastric cardiac variceal bleeding. All four had occluded TIPS, which was between the hepatic and portal vein. The interval between initial TIPS placement and revisional procedures with transcaval TIPS varied between three and 31 months; one patient underwent transcaval TIPS twice, with a 31-month interval. After revision of the occluded shunt failed, direct cavoportal puncture at the retrohepatic segment of the IVC was attempted. RESULTS: Transcaval TIPS placement was technically successful in all cases. In three, tractography revealed slight leakage of contrast materials into hepatic subcapsular or subdiaphragmatic pericaval space. There was no evidence of propagation of extravasated contrast materials through the retroperitoneal space or spillage into the peritoneal space. After the tract was dilated by a bare stent, no patient experienced trans-stent bleeding and no serious procedure-related complications occurred. After successful shunt creation, variceal bleeding ceased in all patients. CONCLUSION: Transcaval TIPS placement is an effective and safe alternative treatment in patients with occluded previous TIPS and no hepatic veins suitable for new TIPS.

Transjugular Intrahepatic Portosystemic Shunt with PTFE-Covered Spiral Z-stent: An Experimental Study in Swine

PURPOSE: To improve TIPS patency by inserting polytetrafluoroethylene(PTFE)-covered spiralZ-stents in swine. MATERIALS AND METHODS: Using PTFE covered spiral Z-stents lined with TIPS tract from theportal vein wall to the inferior vena caval orifice of the right hepatic ve i n , TIPS were created in seven youngswine. The animals were followed up by portal ve n o g r a p hy and venous pressure was measured at two - weekintervals for 12 weeks or until shunt occlusion. After sacrifice, resected liver was examined grossly andpre-pared for histology. RESULTS: The fifty percent patency rate using lifetime analysis was 83 % at 4 weeks, 33%at 6 weeks, 17 % at 8 weeks and 0% at 10 weeks. Venography demonstrated that the predominant sites of stenosiswere the portal vein wall(2/6), the TIPS tract(2/6) and the IVC orifice of the right hepatic vein(2/6). One swinedied 11 days after TIPS due to illness, and bile leaks were discovered in two of the seven animals. Histologicstudy demonstrated intimal hyperplasia in either the portal vein wall or the end of the stent at which the IVCorifice was located, as well as thrombus and pseudointimal hyper-plasia in the TIPS tract. CONCLUSION: P T F E -c overed spiral Z-stents were easily placed and significantly im-proved TIPS patency.

Efficiency of Variceal Embolization during Transjugular Intrahepatic Portosystemic Shunt (TIPS) with StainlessSteel Coil

PURPOSE: To evaluate the efficiency of variceal embolization using a stainless steel coil during TIPS forrecurrent variceal bleeding. MATERIALS AND METHODS: In 53 of a total of 141 patients who underwent TIPS forgastric or esophageal variceal bleeding between August 1991 and Jan 1998 we performed variceal embolization usinga stainless steel coil during the procedure. To compare embolized and non-embolized cases the cumulativerebleeding rate was calculated by the Kaplan-Meier method and statistical significance was analyzed using theLog-rank test. RESULTS: Of the 33 patients who suffered recurrent variceal bleeding, 14 had undergone varicealembolization and 19 had not. One-year, two-year and three-year rebleeding rate in embolized and non-embolizedcases were 23%/12%, 31%/25%, and 53.7%/42%, respectively. Cumulative rebleeding rates are highest within two yearsin embolized cases and highest after two years in non-embolized cases, however there is no statisticalsignificance between the two groups(p>0.05). CONCLUSION: Variceal embolization with stainless steel coil duringTIPS does not effectively prevent recurrent variceal bleeding.

The Usefulness of CO2 Indirect Portography in Transjugular Intrahepatic Portosystemic Shunt(TIPS)

PURPOSE: To determine the usefulness of carbon dioxide(CO2) indirect portography during TIPS procedure. MATERIALS AND METHODS: We evalvated eight patients who had undergone TIPS due to variceal hemorrhage or ascites caused by portal hypertension. All patients but one with complete situs inversus underwent wedged right hepatic venography for visualization of the portal vein using CO2. For CO2 indirect portal venography, 50cc of CO2 was injected by hand without prior injection of a small amount of CO2. In three patients a 5-F angiographic catheter was wedged into the right hepatic vein, and in the other five a 9-F sheath from a Ring 's transjugular access set was adjunctively wedged into the right hepatic vein over the 5-F catheter. The time required for portal vein puncture was defined as the time between the indirect portal venography procedure and the first procedure after successful portal vein puncture. RESULTS: All patients successfully underwent TIPS without any immediate complication. The portal vein was visualized by CO2 in 7 of 8 patients (87.5 %). Two of three patients who underwent indirect portography with only a 5-F catheter wedging demonstrated opacification of the right portal vein; in the remaining patient the portal venous system was not visualized. Of the five patients who underwent indirect portography with an adjunctive 9-F sheath wedged in the right hepatic vein, four showed opacification from the peripheral to the main portal vein, and in the other, the only right peripheral portal vein was opacified. The mean time for portal vein puncture was 20.5 minutes. CONCLUSION: For visualization of the portal venous system during TIPS procedure, the use of CO2 indirect portography is feasible.

Combined Therapy of Transjugular Intrahepatic Portosystemic Shunt(TIPS) and Transcatheter Hepatic ArteryChemoembolization (TACE) in Patients with Hepatocellular Carcinoma and Gastroesophageal Variceal Bleeding

PURPOSE: To evaluate the efficacy of combined TIPS and superselective TACE therapy in patients withhepatocellular carcinoma and variceal bleeding. MATERIALS AND METHODS: Of a total of 132 patients who underwentTIPS, 14 had hepatocellular carcinoma ; of these six with a patent main portal vein who had undergone TACE wereincluded this study. One underwent TIPS 13 months after TACE, and five underwent TACE at various points during theTIPS follow-up period. TIPS followed the standard procedure, while TACE involved superselective segmental orsubsegmental embolization in four patients, lobar artery embolization in one, and non-selective chemoembolizationin one with on advanced tumor. RESULTS: Except for mild hepatic encephalopathy in two patients, no clinicallysignificant immediate complication was seen after TIPS or TACE. Three patients died due to hepatic failure ; theysurvived for one to three months after combined therapy, a mean of 2.3 months. After combined therapy, otherpatients survived for between five and 49 (mean, 22) months. CONCLUSION: Combined TIPS and TACE therapy iseffective for the threatment of patients with hepatocellular carcinoma and esophagogastric variceal bleeding.

A Method to Prevent Life-threatening Intraperitoneal Bleeding During Transjugular Intrahepatic PortosystemicShunt Creation

PURPOSE: To prevent intraperitoneal bleeding, it is critical that the extrahepatic portal vein should not bepunctured during transjugular intrahepatic portosystemic shunt (TIPS). There has, however, been no procedure fordefining the anatomic relationship between the hepatic capsule and the portal vein segment before shunt formation.To avoid a possibly catastrophic outcome of extrahepatic portal puncture before shunt creation, we thereforedevised a new method; the purpose of this study is to report its efficacy and feasibility. MATERIALS AND METHODS:Whenever a portal vein was punctured, we advanced a 9F sheath over a guidewire into the portal vein before balloondilatation of the tract. Contrast material was then injected through the sheath as this was slowly withdrawn fromthe portal vein towards the hepatic vein. When contrast material extravasated or spilled into the peritonealspace, thus suggesting extrahepatic portal vein puncture, a more peripheral segment of the portal vein waspunctured, and a shunt was created using this new tract. We applied this method to 130 consecutive patients whounderwent TIPS to control variceal bleeding due to liver cirrhosis. In all cases, portography and ultrasonographywere used for immediate confirmation of the procedure. RESULTS: Puncture of the extrahepatic portal vein segmentoccurred in three out 130 (2.3%) patients. In these three, TIPS was successfully created using the methoddescribed above. Clinical and ultrasonographic follow-up showed that no patients suffered intraperitonealbleeding. CONCLUSION: For preventing intraperitoneal hemorrhage during TIPS creation, our method is effective andfeasible.

Revision of Transjugular Intrahepatic Portosystemic Shunt (TIPS)

PURPOSE: To evaluate the feasibility and efficacy of revision of the transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: Sixteen malfunctioning TIPS (10 occlusions, 6 stenoses) in 14 patients of 103 patients (117 procedures) were revised. Fifteen patients underwent revision to control recurrent variceal bleeding after TIPS and one to restore severely stenotic TIPS found on portal venogram obtained during transarterial chemoembolization of a hepatocellular carcinoma. One patient underwent three revisions. The time intervals between initial TIPS placement and revisional procedures varied between four and 43 months (mean, 17.6 months). Nine occlusions and four stenoses were treated with an additional stent placed in a parallel or overlapping fashion with transjugular approaches. Two stenoses and one acute occlusion were treated with balloon dilatation involving transfemoral approaches. RESULTS: In patients with complete occlusion of TIPS, the sites of occlusion were all within the stent, with or without associated stenosis of the hepatic vein. In five of six patients, with TIPS stenosis, however, the stenoses were located at the hepatic vein just distal to the stents, rather than within the stents. The procedures for revision were in all cases technically feasible and hemodynamically successful. No significant procedure-related complications were encountered. CONCLUSION: The revision of TIPS is a safe and effective method in cases of its partial or complete occlusion.

Transjugular Intrahepatic Portosystemic Shunt: Results and Prognostic Factors in Patients with Post-necrotic Liver Cirrhosis

PURPOSE: To evaluate the effectiveness of transjugular intrahepatic portosystemic shunt(TIPS) in the management of gastroesophageal variceal bleeding and predictive factors for long-term survival in patients with post-necrotic liver cirrhosis. MATERIALS AND METHODS: A total of 49 patients with post-necrotic liver cirrhosis underwent TIPS over a recent three-year period. Forty-five had a history of hepatitis B viral infection, and four,of hepatitis C viral infection. In all patients, the indication for the procedure was variceal bleeding. Child-Pugh class was A in seven patients, B in 16 and C in 26 patients at the time of the last bleeding. The effectiveness of portal decompression and bleeding control was evaluated. Long-term survival was calculated by the Kaplan-Meier method and predictive factors were analyzed using the Wilcoxon test. RESULTS: The procedure was technically successful in all cases. The portosystemic pressure gradient decreased significantly from 21.4+/-6.4mmHg to 12.0+/-5.1mmHg(N=45). Active variceal bleeding was controlled in 34 of the 37 emergency patients. The total length of follow-up was from one day to three and a half years(mean: 383+/-357days). Rebleeding developed in 17 patients (35%). Hepatic encephalopathy, either newly developed or aggravated, occurred in 16(32.7%). The thirty-day mortality rate was 20.4%, and the one-year survival rate was 63.8%. The significant predictive factors for poor prognosis were Child-Pugh class C and post-TIPS hepatic encephalopathy. CONCLUSION: TIPS is effective in portal decompression in the patients with variceal bleeding due to post-necrotic liver cirrhosis. The Child-Pugh classification and hepatic encephalopathy after TIPS are considered to be significant predictive factors for long-term survival.

Transjugular Intrahepatic Portosystemic Shunt in Patients with Active Variceal Bleeding Due to Portal Hypertension and Portal Vein Thrombosis

PURPOSE: To evaluate the feasibility and efficacy of transjugular intrahepatic portosystemic shunt (TIPS) in patients with active variceal bleeding due to liver cirrhosis and pre-existing portal vein thrombosis. MATERIALS AND METHODS: Of a total of 123 patients who underwent TIPS, 14 patients with intractable variceal bleeding due to portal hypertension and portal vein thrombosis were included in this study. Noncavernomatous portal vein occlusion was seen in eight patients, and complete portal vein occlusion with cavernomatous transformation in six. For all patients, the methods used for TIPS placement were the same as those used in patients with patent portal veins. In seven of eight patients with noncavernomatous occlusion, right hepatic vein-right portal vein shunting was performed; in one with noncavernomatous occlusion, a shunt was created between the right hepatic and left portal vein. In five of six patients with cavernomatous occlusion, the right hepatic and main portal vein were connected via a collateral vein. RESULTS: The procedures were technically successful in all except one patient. Immediate hemostasis was achieved after all technically successful procedures, and no significant complications were encountered. Minor complications were noted in six patients (three biliary tree punctures, one transperitoneal puncture, one splenic vein perforation, one hepatic subcapsular hematoma). CONCLUSION: TIPS is a technically feasible and hemodynamically effective procedure, even in patients with active variceal bleeding due to cirrhosis and complete portal vein occlusion.

Porto-systemic Collateral Pathways in portal Hypertension: Correlation of CT and Angiography

In portal hypertension, hepatopetal flow is rerouted away from the liver through collateral pathways to low pressure systemic vessels. Information about collateral pathways is relevant, especially when interventional procedure or surgery is contemplated, because inadvertent disruption of these veins can cause significant bleeding. Dynamic CT and spiral CT with a bolus injection of contrast material have to a significant extent recently replaced angiography. The porto-systemic collateral pathways have, however, been classified and described according to location or frequency in a majority of previous reports. This essay illustrates variable porto-systemic collateral blood flow pathways, with CT and angiography correlation.