Venous recanalization by metallic stents after failure of balloon angioplasty or surgery: Four-year experience

Purpose: This retrospective study describes our updated experience in treating venous stenoses and occlusions with metallic endovascular stents. Methods: Gianturco, Palmaz, and Wallstent stents were placed in 55 patients over a 4-year period. Stent sites included the subclavian veins (9), innominate veins (3), superior vena cava (4), inferior vena cava (3), iliac veins (29), femoral veins (5), and portal veins (6). The most common indications for stent placement were malignant stenoses and chronic pelvic venous occlusions. Venoplasty and/or urokinase were used as ancillary therapy. Patients were anticoagulated for 3–6 months. Follow-up included clinical assessment and duplex ultrasound. Results: Lifetable analysis shows 59%, 63%, and 72% primary, primary assisted, and secondary 1-year patency rates, respectively. The 4-year primary patency rates were the same. Duration of patency depended on the venous site. Death was a complication of stent placement in 2 patients and 12 patients died within 6 months after stent placement from primary disease progression. Although early failures were more common in stents placed across occlusions than stenoses, 1-year secondary patency rates were comparable. Primary patency rates were only slightly lower in patients with malignant obstruction than in patients with benign disease. Conclusion: Endovascular stent placement provides a nonsurgical alternative for reestablishment of venous flow and symptomatic relief in patients with benign as well as malignant venous obstruction. Received: 0/00/00/Accepted: 0/00/00     

Treatment of Pelvic Venous Spur (May–Thurner Syndrome) with Self-Expanding Metallic Endoprostheses

Purpose: The application of self-expanding metallic endoprostheses (stents) to treat symptomatic pelvic venous spurs as an alternative to surgery. Methods: Wallstents with a diameter from 14 to 16 mm and one Cragg stent were placed in the left common iliac vein of eight patients (seven women, one man; mean age 42 years) with a symptomatic pelvic venous spur (left deep venous thrombosis or post-thrombotic leg swelling). Four patients had surgical thrombectomy prior to stent placement. Results: Technical success with immediate reduction of left leg circumference was achieved in all eight patients. A primary patency rate of 100% was observed during an average follow-up of 3 years (range 10–121 months). There were no procedural or stent-related complications. Conclusion: The percutaneous transfemoral placement of self-expanding metallic stents is an effective minimally invasive alternative to surgery in the treatment of symptomatic pelvic venous spur. Received: 0/00/00/Accepted: 0/00/00     

Primary stenting for complex atherosclerotic plaques in aortic and iliac stenoses

Purpose: To evaluate the efficacy of primary stenting for complex atherosclerotic plaques in aortic and iliac stenoses that are not amenable to balloon angioplasty alone. Methods: Nineteen patients with complex atherosclerotic plaques were treated with a Palmaz stent (n= 19), Wallstent (n= 1), Strecker stent (n= 1), or Memotherm stent (n= 1). A total of 22 stenoses presenting with complex plaque morphology including ulcerated plaques, ulcerated plaques with focal aneurysms, plaques with heavy calcification, severely eccentric plaques, plaques with overhanging edge, and plaques with spontaneous dissection were stented. The lesions were in the aorta (n= 1), common iliac artery (n= 19), or external iliac artery (n= 2). Results: Immediate angiography after stent placement revealed restoration of patency of the stented segment. Focal aneurysms and ulcerated areas were occluded in the follow-up angiographies obtained 4–12 weeks after the procedure. In one case with poor distal runoff and multiple complex lesions of the iliac artery, subacute occlusion occurred. Clinical and angiographic follow-up (3–46 months) revealed patency of all other stented segments. Conclusion: Primary stenting is an effective and reliable approach for complex plaques in stenoses. Patency of the arterial segment with a smooth lumen can be created without the risk of acute complications such as distal embolization, dissection, or occlusion.     

Assessment of a Polyester-Covered Nitinol Stent in the Canine Aorta and Iliac Arteries

Purpose: To evaluate the patency and healing characteristics of a woven polyester fabric-covered stent in the canine model. Methods: Twenty-four self-expanding covered stents were placed in the infrarenal aorta and bilateral common iliac arteries of eight dogs and evaluated at 1 (n = 2), 3 (n = 2), and 6 (n = 4) months. Stent assessment was done using angiography prior to euthanasia, and light and scanning electron microscopy. Results: Angiographically, just prior to euthanasia, 8 of 8 aortic and 14 of 16 iliac endovascular covered stents were patent. Histologically, the stented regions showed complete endothelialization 6 months after graft implantation. A neointima had formed inside the stented vessel regions resulting in complete encasement of the fabric-covered stent by 3 months after graft implantation. Medial compression with smooth muscle cell atrophy was present in all stented regions. Explanted stent wires, examined by scanning electron microscopy, showed pitting but no cracks or breakage. Conclusion: The covered stent demonstrated predictable healing and is effective in preventing stenosis in vessels 10.0 mm or greater in diameter but does not completely preclude stenosis in vessels 6.0 mm or less in diameter.     

PTA arid stenting of benign venous stenoses in the pelvis: Long-term results

Purpose: To provide follow-up data on endovascular intervention for venous stenoses in the pelvis. Methods: Between 1985 and 1995, 35 patients presented with 42 stenoses of the pelvic veins after operative thrombectomy and creation of an arteriovenous fistula, combined with intraoperative venous angioscopy. All patients underwent angioplasty and, if unsuccessful, percutaneous insertion of an endovascular stent (n = 7). Results: Angioplasty with and without endovascular stenting was technically successful in 34 of 35 patients (97%). Average length of the stenoses was 20.6 mm (range 10–90 mm), average diameter before dilation 4.1 mm (range 2–6 mm), and average diameter after dilation 10.1 mm (range 5–18 mm). Intraoperative angioscopy showed pathologic findings (intimal laceration or residual thrombotic material) in 14 patients. After an average follow-up period of 4.13 years, 24 (69%) patients had patent veins. The difference in the primary patency rate between patients with angioscopically abnormal veins (6 of 14 patients, corresponding to a patency rate of 43%) and patients with angioscopically normal veins after thrombectomy (18 of 21 patients, corresponding to a patency rate of 86%) was statistically significant (p < 0.01, log rank test). Conclusions: Percutaneous transluminal angioplasty and/or stenting are good treatment modalities for pelvic vein stenosis following surgical thrombectomy. Angioscopically abnormal veins have a poorer long-term patency, regardless of the type of intervention.     

Directional atherectomy in iliac stent failure: Clinical technique and histopathologic correlation

Purpose: To assess the feasibility and efficacy of directional atherectomy in the treatment of iliac stent stenosis or occlusion and to evaluate the histologic composition of excised atherectomy specimens. Methods: Directional atherectomy of six occluded and 10 severely stenosed iliac stents was undertaken in 12 patients at a mean interval of 28 months (range 3–69 months) after stent insertion for occlusive aortoiliac disease. In cases of stent occlusion, atherectomy was preceded by low-dose thrombolysis. In all patients stent clearance with return of femoral pulses was achieved within 24 hr and there were no significant complications. All excised specimens were sent for histologic examination. Results: Eleven patients (92%) remain symptom free with unlimited walking distance at a mean follow-up interval of 11.5 months (range 3–31 months) after treatment. Histologic examination revealed typical myointimal hyperplasia at three excision sites, intimal fibrosis at three sites, atheroma at four sites and organized thrombus at six sites. Conclusion: Atherectomy offers an effective treatment in iliac stent occlusion and restenosis with no significant adverse effects. Debulking of these lesions seems to offer a more logical approach than simple balloon angioplasty. Clinical and duplex follow-up confirms satisfactory outcome within the first year but longer-term results are not yet known. The histologic data obtained demonstrate that stent restenosis and occlusion are likely to be multifactorial, and challenge the assumption that myointimal hyperplasia is the sole cause of iliac stent occlusion.     

Metallic stent placement for treating peripheral outflow lesions in native arteriovenous fistula hemodialysis patients after insufficient balloon dilatation

OBJECTIVE: The purpose of this study was to report our experience with metallic stent placement in the peripheral outflow veins in native arteriovenous fistula (A-V fistula) hemodialysis patients after insufficient balloon dilatation. MATERIALS AND METHODS: During the past 4 years, 12 A-V fistula dialysis patients in our hospital underwent metallic stent placement in the peripheral outflow veins to restore vascular access. The indications for metallic stent placement in our study included (1) recoil stenosis of outflow vein in six patients; (2) outflow venous rupture in two patients and dissection in one patient; and (3) large residual adherent thrombus in outflow aneurysms in three patients with thrombosed (arteriovenous) access. Self-expandable Wallstent or Jostent (Jomed, Abbott Laboratories) of appropriate size (6-10 mm in diameter) was chosen for use in these patients. Kaplan-Meier survival analysis was used to calculate the access patency rates. RESULTS: Twelve patients received stents. Eleven patients (92%) underwent successful dialysis after the procedure. One patient experienced complications due to incorrect positioning of the stent at the anastomotic site, causing flow compromise. The primary patency (+/- standard error) of the vascular access at 3, 6, 12, and 24 months was 92% +/- 8%, 81% +/- 12%, 31% +/- 17%, and 31% +/- 17%, respectively. The secondary patency of the vascular access at 3 months was 92% +/- 8%, and 82% +/- 12% at 6, 12, and 24 months each. CONCLUSION: Metallic stent placement is safe and effective in treating peripheral venous lesions in native A-V fistula hemodialysis patients after unsatisfactory balloon dilatation.     

Suitability of incorporated vascular stents for surgical patch-plasty: An experimental study

Purpose: Evaluate the feasibility of expanding arterial and venous stents incorporated into the vessel wall by surgical patch-plasty in an experimental study. Methods: An 8-mm Wallstent was percutaneously implanted into the carotid artery of 11 sheep and into the ipsilateral jugular vein in three of them. Three months after implantation, a patch-plasty was performed on the incorporated stents using a 0.4-mm-thick synthetic patch made of polytetrafluoroethylene (PTFE). Stent patency was monitored by color-coded duplex ultrasound and angiography for 6 months after operation. Results: No suture dehiscence or aneurysm formation were observed. Nine of 11 arterial and 2 of 3 venous stents remained fully patent during follow-up. In arteries, complications encountered were a complete stent thrombosis early after surgery, as well as a floating thrombus in the stent, found at final angiography after 6 months. In veins, one partial stent thrombosis was observed. Microradiographic and histological examinations revealed marked intimal hyperplasia in both arterial and venous stents. Intimal hyperplasia was significantly more pronounced in patched than in stented arterial segments (p<0.005). Conclusion: Patch-plasty surgery of previously incorporated vascular stents is technically feasible. Midterm patency rates were acceptable.     

Management of failing prosthetic bypass grafts with metallic stent placement

Purpose: To evaluate the role of metallic stents in treating stenoses involving prosthetic arterial bypass grafts. Methods: Patients undergoing stent placement within a failing prosthetic bypass graft, during a 41-month period, were reviewed for treatment outcome and complications. The indications for stent placement in 15 patients included severe claudication (n= 3), rest pain (n= 9), and minor or major tissue loss (n= 3). Lesions were at the proximal anastomosis (n= 6), the distal anastomosis (n= 3), or within the graft (n= 6). Results: Treatment with metallic stents was successful in all patients. There was one acute stent thrombosis, successfully treated with thrombolytic therapy. Follow-up data are available for a mean duration of 12.3 months. The mean duration of primary patency was 9.4 months with 6- and 12-month primary patency rates of 51.9% and 37.0%, respectively. The mean duration of secondary patency was 12.1 months with 6- and 12-month secondary patency rates of 80.0% and 72.7%, respectively. Two patients with discontinuous runoff and preexisting gangrene required a below-knee amputation. Six patients were revised surgically after stent placement (at a mean of 10.8 months). Three late deaths occurred during follow-up. Conclusion: Given the mortality risks of surgical revision and the reduced life expectancy of this patient population, metallic stent placement represents a viable, short-term treatment option for stenoses within or at the anastomoses of prosthetic grafts. Further evaluation is warranted to compare intragraft stent placement with surgical graft revision.     

Extensive acute deep vein thrombosis of the iliocaval segment: midterm results of thrombolysis and stent placement

PURPOSE: To evaluate patency and clinical outcome in patients treated with catheter-directed thrombolysis and stent placement for acute extensive thrombosis affecting the iliocaval segment. MATERIALS AND METHODS: During a 10-year period (1994-2005), 37 patients with 44 limbs (26 female, median age 31 years) with acute extensive venous thrombosis affecting the iliocaval segment were treated with catheter-directed thrombolysis. Angioplasty and stent placement was performed in 36 limbs (82%) for underlying stenosis or residual thrombosis. A prospectively registered database was analyzed in combination with a telephone interview about clinical symptoms. RESULTS: Technical success was achieved in all 44 limbs and clinical success in 42 of 44 (96%) limbs. Primary patency after a median imaging follow-up interval of 16 months was 34 of 44 (77%) limbs, assisted primary patency was 38 of 44 (86%) limbs, and secondary patency was 39 of 44 (89%) limbs. Thirty of 44 (68%) limbs were asymptomatic after a median clinical follow-up of 27 months, eight (18%) limbs were moderately improved, two (5%) limbs were unchanged, two (5%) limbs were moderately worse, and two (5%) limbs had no clinical follow-up. Complications occurred in six (16%) patients, three (8%) of which were major complications. No patient developed symptomatic pulmonary embolism. CONCLUSIONS: Catheter-directed thrombolysis and stent placement is a safe and effective treatment for acute iliocaval thrombosis. Clinical midterm results are encouraging. Thrombolyzed and stented segments remain patent in the vast majority of patients after 16 months. Primary and aggressive stent placement in the iliocaval vein segments can prevent rethrombosis and ensure patency.     

Percutaneous Treatment of Iliac Aneurysms and Pseudoaneurysms with Cragg Endopro System 1 Stent-Grafts

Purpose: To evaluate the feasibility and short-term follow-up results of treating iliac aneurysms by the Cragg Endopro System 1 stent-graft. Methods: Nine lesions (two pseudoaneurysms and seven atherosclerotic aneurysms) were treated in eight patients by percutaneous implantation of a total of 10 stent-grafts. The procedure was followed by anticoagulation with heparin for 6 days, then antiplatelet therapy. Follow-up was by color Doppler ultrasound scan at 2 days and 3 months after the procedure for all patients, and by venous digital subtraction angiography and/or angio-CT up to 12 months later for four patients. Results: Initial clinical success rate was 100% and there were two minor complications. In one case the delivery system was faulty resulting in failure to deploy the stent-graft. An additional device had to be used. At 3–12 months all prostheses were patent but one patient (12.5%) had a minimal pergraft leak. Conclusion: Percutaneous stent-grafting with this device is a safe and efficacious treatment of iliac artery aneurysms. Received: 0/00/00/Accepted: 0/00/00     

Early detection and treatment of hemodialysis access dysfunction

Purpose: To assess the usefulness of a program for the early detection of hemodialysis graft dysfunction and the impact on graft survival of percutaneous transluminal angioplasty (PTA) and stent implantation to correct venous stenosis. Methods: A program for the early detection of hemodialysis access graft dysfunction was carried out in 110 patients over a period of 80 months. Detection was based on physical examination, flow rate measurements, venous pressure, and analytical determinations performed at dialysis. The stenoses detected were treated by PTA or PTA plus stent deployment. Survival curves compared primary and assisted patency rates for the different graft types. Results: The most important indicators of dysfunction were increased venous pressure and difficulty in cannulation of the graft. Significant stenoses were revealed by 227 (92.2%) of the 246 fistulography procedures performed. PTA results were satisfactory in 100% of the Thomas grafts, 74% of the Brescia-Cimino (BC) grafts, and 53% of the polytetrafluoroethylene (PTFE) grafts. Technical success rates for stent deployment were 92% for BC grafts and 100% for PTFE grafts, while functional success rates were 96% and 97%, respectively. The difference in the primary patency (P1) and assisted patency (AP) values was statistically significant for all three graft types. There was no significant difference in the patency rates for grafts treated by PTA alone or by PTA and stent deployment. Conclusion: A surveillance program helped prevent graft thrombosis, and intervention as required achieved excellent primary and assisted patency rates. Stent deployment salvaged a considerable number of accesses but did not significantly extend access survival time.     

Evaluation of Silicone as an Endovascular Stent Membrane: In Vivo Canine Studies

Purpose: Comparative evaluation of the biological effects of a silicone-covered stent versus a bare-metal stent, in an animal model. Methods: Twelve stent implants were placed in the iliac arteries of six adult dogs. Each animal received one 8-mm × 20-mm silicone-covered stent (Permalume; Boston Scientific Vascular, Watertown, MA, USA), in the right iliac artery and one Wallstent (Boston Scientific Vascular) of the same diameter and length in the left iliac artery, during systemic anticoagulation. Angiography was performed before and after implantations. Animals were then allowed to recover and no platelet suppression was given during a 6-week interval, after which the animals were euthanized. The stented arteries were isolated and pressure-fixed in situ with 10% buffered formalin at a pressure of approximately 100 mmHg for a period of 1 hr. Two of 12 stented specimens were opened lengthwise and the luminal surfaces were photographed. Ten of 12 stented arterial segments were encased in methacrylate, then stained with hematoxylin and eosin. Neointimal thickness was quantified on histologic cross-section, for both bare and covered stents. The mean neointimal thicknesses were compared for significant difference using a student t-test. Results: All implants were widely patent at 6-week follow-up angiography. Histologic analysis showed bare metal stents covered by a thin uniform lining of neointima composed of smooth muscle cells in a hyaline matrix (mean thickness of 189 ± 47 μm). Silicone covered stents were devoid of neointima. There was no chronic thrombus or mature endothelium noted anywhere upon the internal silicone surfaces of any of the specimens. There was no foreign body reaction to the silicone cover. Conclusion: Short-term implantation of a silicone-lined Wallstent in canine iliac arteries is well tolerated. Silicone appears to be inert at 6 weeks in this experimental application.     

Use of the Wallstent in the venous system including hemodialysis-related stenoses

Eighteen patients with a total of 23 venous stenoses or occlusions were treated with the Wallstent. In 5 patients treated for malignant stenosis there was one primary failure due to insufficient stent expansion. The other 4 patients showed rapid relief of their inflow obstruction, all remaining asymptomatic despite later stent occlusion in 1 patient. Four patients were treated for benign postoperative stenoses of the iliac or femoral vein. All stents remained patent for a period of 6 weeks-58 months. Nine patients were treated for one or multiple stenoses along the venous outflow tract of hemodialysis fistulas. Of 14 lesions that were eventually stented, 12 are still patent after 3–27 months (mean 19). However, 10 secondary interventions (eight percutaneous transluminal angioplasty (PTA), two stents) and three additional stent procedures for new lesions were necessary. Although our experience is limited, we believe that patients with tumor compression or postoperative strictures of large veins benefit from treatment with stents. Stenting of venous outflow stenoses in hemodialysis fistulas can significantly prolong stent function, however, PTA should always be the first treatment of choice.     

Therapeutic Consequences of Variation in Intraarterial Pressure Measurements After Iliac Angioplasty

Purpose: To assess the accuracy of intraarterial measurement of transstenotic pressure gradients for the detection of hemodynamically suboptimal iliac angioplasty. Methods: In 14 patients, referred for diagnostic angiography, mean pressure gradients in the aorta and iliac artery were obtained twice, using a double-sensor pressure catheter. Additional iliac measurements were performed during pharmacologically induced flow augmentation. Repeatability was assessed by calculation of the mean difference plus standard deviation (MD ± SD) and repeatability coefficient (2 × SD). These results were extrapolated to 137 iliac angioplasty procedures with secondary stenting where there was a residual pressure gradient > 10 mmHg. Results: MD ± SD for repeated measurements at rest and during flow augmentation were 0 ± 2 mmHg and 1 ± 3 mmHg, respectively. Repeatability coefficients were 3 and 6 mmHg. Mean pressure gradients after hemodynamically insufficient angioplasty were 8 ± 7 mmHg at rest and 17 ± 5 mmHg following vasodilatation. Inaccurate pressure recordings may have led to inappropriate stent placement in less than 2.5%, and inappropriate denial of stent placement in less than 5% of the lesions. Conclusion: Variability of intraarterial pressure measurements has little consequence in the detection of hemodynamically significant stenosis after angioplasty. Received: 0/00/00/Accepted: 0/00/00     

Access-Related venous stenoses and occlusions: Treatment with percutaneous transluminal angioplasty and dacron-covered stents

Purpose: To determine the effectiveness of using Dacron-covered stents to treat access-related venous stenoses and occlusions. Methods: Twenty-two Dacron-covered stents were placed in 20 patients: in the basilic or axillary vein (n = 2), cephalic vein (n = 3), subclavian vein (n = 5), and at the venous anastomosis of the polytetrafluoroethylene (PTFE) implant graft (n = 10). Results: Initial technical success was 100%. The cumulative primary and secondary patency rates were 57% and 83% at 6 months, 29% and 64% at 12 months, and 29% and 53% at 18 months. A statistically significant difference in the stent patency was revealed by comparing the patients with stents in the subclavian vein and patients with upper arm stents. The secondary patency rates of the upper arm stents were 73% after 6, 12, and 18 months. Conclusions: Percutaneous placement of Dacron-covered stents is a safe and effective procedure for salvage of a dialysis fistula. First results are promising, with a tendency to prolongation of the time interval between reinterventions.     

An Experimental Study of Endovascular Stenting with Special Reference to the Effects on the Aortic Vasa Vasorum

Purpose: To evaluate the effects of bare stents and covered stents on the aortic wall, especially the vasa vasorum. Methods: Eight bare stents and nine covered stents were placed in the infrarenal aorta of nine dogs. The dogs were euthanized at 4–45 weeks after stent placement. The vasa vasorum was evaluated by microstereoscopy with vascular casting, and the histopathology of the aortic wall was examined by light microscopy. Results: In the unstented normal aorta, vasa vasorum nourished the adventitia and the outer media, and the intima and inner media were avascular. In the stented segment, vascular dilatation and proliferation of vasa vasorum, medial atrophy, and intimal hyperplasia were observed, more prominent for covered stents than for bare stents. Conclusion: Intravascular stent placement caused not only medial atrophy and intimal hyperplasia but also proliferation of the vasa vasorum, probably due to hypoxia in the aortic wall. Received: 0/00/00/Accepted: 0/00/00     

Determination of stent stenosis: An in vivo experimental comparison of intravascular ultrasound and angiography with histology

Purpose: To compare intravascular ultrasound (IVUS) and angiography with histology in determining the degree of stent stenosis in an in vivo experiment. Methods: In 16 sheep, a total of 64 stents were implanted into the external iliac arteries. Two stents were inserted on either side. Patency was followed by angiography and IVUS. Four types of stent were used: two Dacron-covered (Cragg Endopro and heparinized Cragg Endopro) and two non-covered (Cragg and Memotherm stents). Eight animals were killed after 1 month, eight others after 6 months. Histological sections were prepared from the stented vessels. Measurements of the patent and total stent diameters determined by IVUS, angiography, and histology were compared. Results: Correlation between IVUS and angiography was 0.75, between IVUS and histology 0.77, and between angiography and histology 0.85. A mean stent stenosis of 17 ± 11% (range 0–51%) was found on angiography, of 10 ± 11% (0–46%) on IVUS, and of 20 ± 11% (4%–49%) on histology. In comparison with histology, IVUS underestimated the degree of stenosis by 10 ± 8%, and angiography underestimated it by 3 ± 6%. Resolution of IVUS was calculated to be about 0.35 mm and that of angiography to be about 0.15 mm. Conclusion: Under experimental conditions, IVUS was not superior to angiography in determining the degree of stent stenosis in long-segment stenoses of iliac artery stents, when measurements were correlated with histology. Angiography is sufficient for following the patency of iliac artery stents.     

Patency and reintervention rates during routine TIPSS surveillance

Purpose: To assess the medium-term outcome of transjugular intrahepatic portosystemic stent shunts (TIPSS) by measuring the incidence of shunt obstruction or failure during routine surveillance and the number of interventions performed. Methods:This is a retrospective study covering a 4-year period, from 1992 to 1996, during which 102 TIPSS procedures were performed. Indications for treatment were variceal bleeding (76%) and refractory ascites (24%). Follow-up protocol after TIPSS included transfemoral or transjugular portal venography and measurement of portosystemic pressure gradient (PPG) at 3 months, 12 months, and then at yearly intervals. The results of the first 155 venograms on 62 patients (mean follow-up 14 months) have been reviewed and Kaplan-Meier analysis performed. Results: One hundred and thirty-seven of 155 (88%) examinations showed patent shunts. Fifty-six of 137 (41%) of the patent TIPSS had elevated PPG with signs of stenosis. The majority (41/56) of shunt stenoses with elevated pressure gradients were related to neointimal hyperplasia in the hepatic venous aspect of the shunt. Interventions used to reduce the pressure gradient or to restore patency included: angioplasty (62/102 interventions), additional stents (21/102), a second TIPSS procedure (2/102), and thrombolysis or thrombectomy (4/102). The primary patency rate was 66% at 1 year (52% at 2 years). Primary assisted patency was 72% at 1 year (58% at 2 years). Secondary patency was 86% at 1 year (63% at 2 years). Conclusion: The majority of TIPSS shunts will remain patent when regular portal venography, with appropriate intervention, is undertaken. Although there is a high reintervention rate this mainly takes the form of balloon angioplasty.     

Recurrent TIPS failure associated with biliary fistulae: Treatment with PTFE-covered stents

Purpose: To evaluate the efficacy of covered stents for the treatment of transjugular intrahepatic portosystemic shunt (TIPS) obstruction in human subjects with identified or suspected biliary fistulae. Methods: Five patients were treated for early failure of TIPS revisions. All had mid-shunt thrombus, and four of these had demonstrable biliary fistulae. Three patients also propagated thrombus into the native portal venous system and required thrombolysis. TIPS were revised in four patients using a custom-made polytetrafluoroethylene (PTFE)-covered Wallstent, and in one patient using a custom-made PTFE-covered Gianturco Z-stent. Results: All identified biliary fistulae were successfully sealed. All five patients maintained patency and function of the TIPS during follow-up ranging from 2 days to 21 months (mean 8.4 months). No patient has required additional revision. Thrombosis of the native portal venous system was treated with partial success by mechanical thrombolysis. Conclusion: Early and recurrent failure of TIPS with mid-shunt thrombosis, which may be associated with biliary fistulae, can be successfully treated using covered stents. Stent-graft revision appears to be safe, effective, and potentially durable.