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Purpose: To retrospectively evaluate the safety and effectiveness of the Covera stent graft (SG) for the treatment of dysfunctional or thrombosed arteriovenous grafts (AVGs)., Materials and Methods: Within 29 months (February 2016-August 2018), 79 patients underwent Covera SG placement in the authors' department for the treatment of dysfunctional AVGs. Data were available for 64 patients who underwent 64 procedures, using 64 devices. Minimum follow-up was 6 months, unless reintervention occurred. Mean follow-up was 277 days (6-923 days). Treatment characteristics were 51 cases with venous-graft anastomosis (VGA) stenosis (79.7%), 13 cases of puncture zone stenosis (20.3%), 14 cases of in SG stenosis (21.9%), 8 cases of pseudoaneurysm treatment (12.5%) (1 treatment area might have had more than 1 characteristic). Thirty-six patients presented with thrombosis (56.2%), and 31 of 64 case were de novo treatment areas (48.4%). Primary outcome measurements were technical success and post-intervention primary patency (PIPP) at 6 months, whereas secondary outcome measurements included factors influencing primary outcome., Results: Technical success was 100%. Median PIPP was 336 days, and 73.6% of treatment areas were patent at 6 months. There were no significant differences in terms of PIPP when de novo treatment areas were compared with restenotic areas (519 vs. 320 days, respectively; P = .1); patients who presented with versus those who presented without thrombosis (320 vs. 583 days, respectively; P = .07); puncture zone stenosis or elsewhere (329 vs. 686 days, respectively; P = .52); and VGA stenosis or elsewhere (336 vs. 335 days, respectively; P = .9)., Conclusions: Use of the Covera SG for AVG treatment was safe and effective in every type of treatment area presented in this retrospective analysis., (Copyright © 2019 SIR. Published by Elsevier Inc. All rights reserved.)

Background: A well-established method to preserve failing synthetic arteriovenous grafts (AVGs) dialysis accesses is percutaneous transluminal angioplasty (PTA). Nevertheless, the one-year primary patency rate following PTA is approximately 25%. This study was designed to compare the angiographic and clinical outcomes following stent-graft insertion versus angioplasty and/or bare metal stenting (BMS) of recurrently failing AVGs, because of anastomotic and/or venous outflow stenoses., Methods: Self-expanding stent-grafts were deployed for the treatment of failing AVGs in case of recurrent stenosis after treatment with conventional angioplasty or bail-out BMS. Regular angiographic follow-up was scheduled every two months the first six months and every three months thereafter. Data from previous procedures on the same treatment site were retrieved from our database. Primary patency was defined as a functioning graft with a patent treatment site without angiographic restenosis >50% and without any subsequent repeat procedures. Outcome data were analyzed by Kaplan-Meier analysis., Results: In total, 35 patients previously treated with angioplasty and/or BMS for the treatment of recurrent significant AVG stenosis (group PTA), underwent stent-graft placement of the same treatment site (group SG). Of those, 20 patients had undergone angioplasty and 15 bail-out BMS. Mean lesion length was 4.8±1.7cm. Primary patency was significantly improved in the SG group (Hazard Ratio [HR] = 0.2 [95% CI= 0.11-0.36], P=.0001) by log-rank test. The estimated six and 12-month patency rates were 76.9% vs. 25.7%, and 61.4% vs. 8.6% for groups SG and PTA respectively, (P<.0001)., Conclusions: Stent-graft placement significantly improves primary patency of anastomotic and venous outflow stenoses in recurrently failing prosthetic arteriovenous grafts.

Despite immediate open surgery, aortoenteric fistula (AEF) remains a highly lethal condition. Endovascular management is widely employed, although there is no agreement on its role as a definite treatment or, because of a high incidence of recurrent bleeding and sepsis, as a bridge to open repair. Two cases of secondary AEFs after distant elective abdominal aortic aneurysm repair are presented. The first patient was a 76-year-old man and the second one a 70-year-old man. Both patients presented with hematemesis, had no signs of sepsis and were successfully managed with endovascular surgery, using aortic cuff extenders. Postoperative course was uneventful for both patients who were discharged on long-term antibiotics. However, during follow-up the first patient was readmitted four times; twice due to infection (at 2 and 6 months, respectively) and twice due to recurrent bleeding (at 5 and 9 months, respectively). The last episode of bleeding was managed with axillobifemoral bypass grafting, removal of the prostheses and closure of the aortic stump and the duodenal defect, but the patient died on the 5th postoperative day from multiple organ failure. The second patient remained asymptomatic until the 16th postoperative month when he developed lumbar spine osteomyelitis as a direct extension of graft infection and was deemed inoperable due to multiple comorbidities. Endovascular management of AEF can achieve satisfactory short-term results. Due to the high rate of recurrent bleeding and sepsis it should be used as a temporary measure and a bridge to open repair, whenever this is feasible.

Purpose: Ureteral patency in malignant ureteral obstruction cases is a therapeutic challenge. We report our long-term experience with palliative treatment for extrinsic malignant ureteral obstruction with percutaneous placement of metal mesh stents., Materials and Methods: From January 1996 to December 2005, 90 patients with a mean age of 59 years (range 35 to 80) with ureteral obstruction due to extrinsic ureteral compression and/or encasement by primary or metastatic tumors, or retroperitoneal lymphadenopathy underwent implantation of self-expandable metal mesh stents. A total of 119 ureters were managed. Followup included urinalysis, blood biochemistry tests and transabdominal ultrasound or intravenous urography., Results: The technical success rate of percutaneous antegrade insertion of ureteral self-expandable metal mesh stents was 100%. Renal biochemistry normalized and hydronephrosis gradually resolved 1 to 2 weeks after stent insertion. Median followup was 15 months (range 8 to 38). Hyperplastic reaction and/or encrustation, or tumor ingrowth developed in 45 stents. Secondary intervention, such as repeat balloon dilation and coaxial stenting, was done to improve patency. Migration was observed in 13 metal stents. The primary and secondary patency rates during followup were 51.2% and 62.1%, respectively. A double pigtail or external-internal stent was inserted in 45 cases in which secondary interventions did not ensure patency., Conclusions: Internal drainage of extrinsic malignant ureteral obstruction with metal mesh stents provides long-term decompression of the upper urinary tract in select cases. Certain problems limit the application of metal mesh stents in the ureter. Further studies are warranted to identify independent predictors of ureteral patency after the application of metal stents for malignant obstruction.

Background and Purpose: Recent reports concerning coronary, carotid, and femoral vasculature have proposed the use of drug-eluting metal stents (MS) to improve clinical and angiographic outcomes. Based on these reports, we used paclitaxel-eluting MS within an animal renal artery lumen and compared the results with those using a bare-metal stent., Materials and Methods: The experimental model in this study was the female pig renal artery. Ten pigs with weights ranging from 25 to 30 kg were used. Twenty stents were placed, two in each animal. The MS placement was randomly performed in either the right or left renal artery of each animal. In 10 arteries, a 3.5 x 18 mm R-stent (group A) was placed; in the remaining 10 arteries, a 3 x 32 mm paclitaxel-eluting coronary stent (T-stent, group B) was inserted. Patency was estimated with the use of digital subtraction angiography, CT angiography, and virtual endoscopy at 24 hours and 1 month poststent placement., Results: The positioning of the MS was successful in all cases. The initial angiographic result was maintained 24 hours after the intervention. No stent migration was seen, except for one paclitaxel stent that was acutely occluded. The one-month patency rate, as demonstrated by angiography, CT angiography, and virtual endoscopy, was 70% (8 arteries) in group A and 90% (9 arteries) in group B. The thickness of the endothelium and of the muscular coat was statistically significantly less in group B compared with group A (P = 0.0352 and P = 0.0046, respectively)., Conclusion: These preliminary experimental study results suggest that the paclitaxel-eluting MS is more efficient than the bare-metal stent when used within the pig renal artery. Further experimental and clinical studies are necessary to validate our preliminary encouraging results.

Purpose: To report the midterm (30%, or flow-limiting dissection). Patients were followed up with regular clinical evaluation, and digital subtraction angiography was scheduled at 6 months and 1 year. Life-table analysis and Kaplan-Meier plotting of angiographic and clinical variables were performed. Cox proportional-hazards regression analysis was employed to adjust for various covariates and search for independent adverse predictors of angiographic and clinical outcome., Results: Infrapopliteal procedures were performed in 29 patients with 32 limbs with CLI; 79.3% of the patients had diabetes and 34.5% had renal disease. A total of 62 coronary PES were deployed in 50 below-knee lesions (mean stent-implanted length, 25.51 mm+/-12.16). Technical success rate was 100%. The 1-year mortality rate was 16.9%, and the limb salvage rate was 88.5%. The 1-year angiographic in-stent primary patency rate was 30.0%, whereas the incidence of in-stent binary (>50%) restenosis was 77.4%. The 1-year incidence of clinically driven repeat interventions was 30.5%. The Cox model calculated renal disease as the only independent predictor of decreased primary patency and increased repeat intervention events. Initial occlusions also adversely affected primary patency., Conclusions: Infrapopliteal PES achieved acceptable clinical results in CLI, even though they failed to inhibit vascular restenosis and decrease the need for repeat interventions. Renal disease and initial occlusions are adverse prognostic factors for infrapopliteal endovascular procedures.

Objective: The purpose of the present study is to compare the standard bare metal stents (BMS) with the Paclitaxel-Drug Eluting Stent (DES) in the ureter of a pig model., Materials and Methods: We report on an experimental study with ten female pigs weighing between 25 and 30 kg. The stents were randomly placed in either the right or left ureter in each of 10 study animals, for a total of 20 stented ureters. Ten ureters were stented with an R-Stent (Orbus Medical Technologies, Hoevelaken Netherlands), and ten with a Paclitaxel-Eluting Coronary Stent (Boston Scientific, Natick, MA, USA). Patency was measured by radiograph of the nephrostomy tract, intravenous urography and virtual endoscopy at 24 hours and 21 days after the initial procedure, respectively., Results: Free flow of urine through the stents into the bladder was documented in all stented ureters 24 hours after stent insertion by radiograph of the nephrostomy tract. At the 21 day follow-up examination, 5 R-Stents were found to be completely occluded and two partially stenosed, whereas no occluded stent was detected in the Paclitaxel-DES group. Pathology examination of the stents at 21 days follow-up showed that the obstructed R-Stents generated severe inflammation with metaplasia of the urothelium. The Paclitaxel-Eluting MS generated a mild inflammatory response within the ureteral lumen at the site of the stent, without hindering ureteral patency. R-stents proved to develop more hyperplasia compared to the Paclitaxel-Eluting MS., Conclusions: Paclitaxel-DES, when compared with the standard R- Stent BMS, generated less inflammation and/or hyperplasia of the surrounding tissues, thus maintaining ureteral patency. Long-term animal trials are required to further validate our results.