Self-expanding Endoprosthesis Research Articles

Treatment with a self-expanding endoprosthesis in patients with stenosis or occlusion at the arteriovenous graft: 6-Month outcomes of a post-marketing surveillance study.

To assess 6-month safety and efficacy of a self-expanding stent graft placement to treat stenotic or thrombosed synthetic arteriovenous access graft at the venous anastomoses. This prospective, multicenter, post-market surveillance study assessed the GORE® VIABAHN® Endoprosthesis (stent graft) in Japanese patients with stenotic or thrombosed vascular access grafts. Key efficacy and safety outcomes were primary patency (PP) and secondary patency (SP) of the target lesion and the vascular access circuit, repeat interventions, technical and clinical success, incidence of adverse and serious adverse events, and device deficiencies through 6 months. The 103 enrolled patients (mean age 71.8 years; 57.3% female) had stent grafts placed in the venous anastomosis of arteriovenous access grafts (on-label). The majority of lesions were stenotic (77.1%) and located in the upper arm (91.4%). Mean lesion length was 42.9 ± 23.6 mm and diameter was 6.7 ± 1.9 mm; 28 patients (27.2%) had elephant trunk placements. Technical and clinical success rates were 100%. At 6 months, Kaplan-Meier estimates of target lesion and circuit PP were 75.1% (95% CI: 65.2, 82.6) and 66.8% (95% CI: 56.4, 75.3), and SP rates were 93.8% (95% CI: 86.7, 97.2) and 93.8% (95% CI: 86.7, 97.2), respectively. Mean cumulative number of reinterventions (0.36; 95% CI: 0.20, 0.51) and incidence of device- or procedure-related adverse events were low (⩽3%). No device deficiencies were reported. The 6-month outcomes of the self-expanding stent graft to treat thrombosed venous anastomoses of synthetic hemodialysis vascular access grafts with stenosis demonstrated safety and effectiveness.

Intraluminal endoscopy in diagnosis and treatment of fluid collections in acute pancreatitis

To improve treatment outcomes in patients with acute pancreatitis through a differentiated approach to transluminal drainage. There were 1074 patients with acute pancreatitis between January 2018 and December 2021 at the Sklifosovsky Research Institute for Emergency Care. EUS was used as a final diagnostic method to determine localization, dimensions, shape and contours of fluid collections. We also assessed content, presence or absence of a capsule and connection with pancreatic ductal system, possibility of intraluminal drainage under EUS control. A plastic stent with rounded ends was installed if homogeneous hypo- and anechoic cavity with clear even contours was detected. The same measure was applied in case of aspiration of serous or serous-hemorrhagic fluid. The indication for installation of covered self-expanding endoprosthesis was inhomogeneous anechoic fluid collection with hyperechoic inclusions (sequesters) and cloudy purulent content. Patients with necrotic forms underwent insertion of a cystonasal drainage tube 7Fr for sanitation of the cavity with 0.05% aqueous chlorhexidine solution. Endoscopic sequestrectomy was performed every 24-48 hours. Stent was removed in 6 (for encapsulated peripancreatic fluid collections) or 1 month (for other types of fluid collections) after discharge. According to the EUS data, endoscopic TLD was performed in 63 (46%) out of 136 patients with fluid collections. Among 63 patients with TLD, connection with pancreatic ductal system was found in 5 (7.9%) patients. These ones underwent pancreaticoduodenal stenting. Twenty-two patients underwent elective sequestrectomy after stenting of necrotic types of fluid collections with fully covered self-expanding stents. Additional percutaneous drainage was required in 11 (45.8%) of 24 patients. Complicated postoperative period was observed in 4 (6.3%) patients with acute necrotic fluid collections (bleeding from the area of pancreatogenic destruction). Four (6.3%) patients died. Autopsy revealed resolution of purulent-inflammatory process in all patients. Intraluminal surgery is possible not only for homogeneous delimited fluid collections, but also for advanced lesions including infected destructions. This approach allows us to consider endoscopic intraluminal drainage as the final minimally invasive method of surgical treatment of pancreatic necrosis. Its effectiveness is up to 45.8%.

Endovascular Treatment of Coarctation of the Aorta with a Self-Expanding Endoprosthesis: How I Do It Using the Braile Dominus® Coarctation Aorta Device

The coarctation of the aorta is a relatively highly prevalent congenital heart disease and may be diagnosed as an underline cause of hypertension in adolescents and adults. The gold standard treatment for coarctation of the aorta in these patients is being replaced - from open surgery to endovascular therapy. Some prostheses have been developed to treat the coarctation with less acute and chronic complications. The Dominus® Coarctation Aorta (Braile Biomédica) is the first self-expandable prosthesis created specifically to treat coarctation of the aorta, reducing possible acute complications, like aortic rupture or aortic dissection. Here, we discuss the step-by-step method for using this prosthesis.

Endoscopic management of esophageal perforation caused by calibrating bougie during laparoscopic sleeve gastrectomy

Background: Laparoscopic Sleeve Gastrectomy (LSG) is one of the most used surgical techniques for the treatment of morbid obesity. The esophageal perforation (EP) secondary to the use of calibrating bougie is a rare complication.Case presentation: A 43-year-old woman with a body mass index (BMI) of 54 kg/m2 underwent LSG. During the use of a calibrating bougie, a distal EP occurred, but it became evident only during the second day after the surgery. The patient was hospitalized in Intensive Care Unit because of respiratory failure and her clinical conditions did not permit a safe surgical treatment. The EP was treated successfully by endoscopic conservative approach with a double-covered self-expanding endoprosthesis (SEMS).Results: The esophageal calibrating bougie, often placed by an anaesthesiologist, is undoubtedly useful during the learning curve of the surgeon to ensure a correct sleeve size; however, it may result in severe and difficult-to-treat iatrogenic lesions.Conclusions: Managing the complications through conservative endoscopy is possible, but in order to support these patients, the immediate availability of an intensive care unit is essential. We underline the importance of a dedicated team of surgeons and anaesthesiologists and a multidisciplinary team to treat major complications in bariatric surgery.

OPTIONS FOR CLOSURE OF RETRO-DUODENAL PERFORATION AFTER ENDOSCOPIC PAPILLOSPHINCTEROTOMY WITH A SELF-EXPENDING STENT

Aim. To explore the possibility for a temporary compression of the perforation hole by endobiliary stenting in close proximity of papillotomy anastomosis. Materials and methods. On the basis of clinical observations, two stenting technologies were compared experimentally in case of retro-duodenal perforation development through the pockets of hepaticopancreatic ampulla and in trial cannulation after the pre-scattering: self-expanding endoprosthesis and tight frame stenting with several plastic stents. Results. Closure of the perforation is provided due to a self-expanding stent, when it occurs in 2mm from papillotomy anastomosis. In case of perforation through the pockets of the ampoule of the major duodenal papilla both tight stenting and self-expanding stenting provide a tight closure. Conclusion. In case of retro-duodenal perforation during trial cannulation after the pre-dissection of hepaticopancreatic ampulla, the tight closure of the perforation at a distance of no more than 2 mm. from papillotomy anastomosis is provided by stenting self-expanding endoprosthesis. In case retro-duodenal perforation through the pockets of the ampulla of the Major duodenal papilla occurs, both methods (tight stenting and stenting by a self-expanding stent) ensure tight closure of the perforation.

17 URETEROCALICOSTOMY FOR THE TREATMENT OF SELECT CASES OF URETEROPELVIC JUNCTION OBSTRUCTION

INTRODUCTION AND OBJECTIVES: Hydronephrosis can be a serious complication of aortic reconstructive surgery, presenting in early or late postoperative period. The incidence and treatment tactics for this infrequent complication are still debated in literature. Our study tries to answer these questions. METHODS: 450 patients following aortofemoral and aortoiliac reconstruction were included. There were 382 (84.9%) males and 68 (15.1%) females with a median age of 65.7 8.3 years. Patients were investigated preoperatively and at 1 week, 3, 6 and 12 months after vascular surgery. Two urologists performed clinical and ultrasound examination, intravenous pyelograms assessment. Patients with preoperatively diagnosed urological pathology were not included into this study. RESULTS: We revealed unilateral hydronephrosis in 8.0% (36/ 450) of patients. 83.3% (30/36) of them had a history of aortic aneurysm resection with aortofemoral bypass grafting and 16.7% (6/36) underwent aortofemoral bypass only (p 0.05). There were 44.4% (16/36) patients with mild obstruction and 55.6% (20/36) patients with extensive ureteral strictures. The mild asymptomatic obstruction resolved spontaneously following 1 month of observation. Patients with late (6–12 months) obstruction developed ureteral strictures and required for active management. They underwent ureterolysis and ureteral resection with ureteroureterostomy. Four of them developed stricture relapse postoperatively. Intraureteral metallic self-expanding endoprosthesis placement was performed to eliminate the obstruction in 3 cases. One patient with obliteration of ureter underwent subcutaneus nephrovesical bypass. CONCLUSIONS: Ureteral obstruction can be a serious complication of reconstructive aortic surgery. This especially concerns to aneurysms of abdominal aorta and patients with graft complications. Early mild asymptomatic obstruction may resolve spontaneously or require ureteral stenting. Late hydronephrosis may contribute to retroperitoneal fibrosis associated with periureteral inflammatory process and extensive ureteral strictures. Intraureteral metallic self-expanding endoprosthesis or subcutaneus nephrovesical bypass placement can be appropriate in patients with contraindications to open reconstructive surgery.

Aortic Neck Dilatation and Endograft Migration Are Correlated With Self-Expanding Endografts

To compare self-expanding and balloon-expandable stent-grafts in terms of aortic neck dilatation and endograft migration. Two-hundred and forty-two patients (178 men; mean age 68 years, range 56-91) underwent elective endovascular repair of abdominal aortic aneurysm. Two-hundred self-expanding (115 Excluder, 48 Endologix, 23 Vanguard, 10 Anaconda, and 4 Talent) and 42 balloon-expandable (Lifepath) endografts were used. All patients underwent contrast-enhanced computed tomography (CT) prior to the intervention, at 1, 3, and 6 months after the procedure, and annually thereafter. Comparison was made between the first and the last follow-up CT scans. Fifty-five (27.5%) of the 200 patients treated with self-expanding endografts had aortic neck dilatation compared to only 3 (7.1%) of the 42 patients treated with balloon-expandable endografts (p = 0.023). Forty-nine (24.5%) patients in the self-expanding group versus only 3 (7.1%) patients of the balloon-expandable group presented with endograft migration (p = 0.034); all had dilated necks. The difference between the means of neck dilatation for the Lifepath balloon-expandable stent-graft and the Excluder self-expanding endoprosthesis was statistically significant (p = 0.011, 95% CI 0.07 to 0.91). Aortic neck dilatation following endovascular AAA repair appears to be correlated with self-expanding endografts, which may contribute to a higher incidence of graft migration compared to that occurring with balloon-expandable endografts.

Neurophysiological monitoring during thoracoabdominal aortic endovascular stent graft implantation☆

The aim of this study was to evaluate the benefit of neurophysiological monitoring during thoracic and thoracoabdominal endovascular stent graft implantation. The spinal cords of 21 patients undergoing endovascular stent graft implantation on the thoracic and thoracoabdominal aorta were monitored with transcranial motor-evoked potentials (tcMEP) and somatosensory-evoked potentials (SSEP). All patients underwent mild systemic hypothermia (34-35 degrees C), constant cerebrospinal fluid (CSF) pressure and vital parameter monitoring. If CSF pressure exceeded 15 mmHg, CSF-drainage was carried out. Three of the 21 patients (14%) exhibited short-term loss of tcMEP and SSEP after the deployment of the self-expanding endoprosthesis. We observed an intraoperative recovery of the evoked potentials in all cases. CSF-drainage was necessary in three of them. One patient, whose potentials were stable intraoperatively, developed paraparesis 3 weeks after the intervention. Neurophysiological monitoring has proved to be an ideal monitoring method to detect spinal cord ischemia during thoracic and thoracoabdominal endovascular stent graft implantation. Due to the advantages of endovascular therapy (no aortic cross-clamping, continuous distal perfusion, and no reperfusion injury), changes in potentials were seldom observed.

Biocompatibility studies of the Anaconda stent-graft and observations of nitinol corrosion resistance.

To validate the deployment, in vivo performance, biostability, and healing capacity of the Anaconda self-expanding endoprosthesis in a canine aortic aneurysm model. Aneurysms were surgically created in 12 dogs by sewing a woven polyester patch onto the anterior side of the thoracic or abdominal aorta. Anaconda prostheses were implanted transfemorally for prescheduled periods (1 or 3 months). Aneurysm exclusion and stent-graft patency were monitored angiographically. Healing was assessed with histological analysis and scanning electron microscopy (SEM). Textile analysis determined the physical and chemical stability of the woven polyester material, while the biostability of the nitinol wires was evaluated with SEM and spectroscopy. All prostheses were intact at explantation. After 1 month, endothelial-like cells were migrating in a discontinuous manner both proximally and distally over the internal collagenous pannus at the device-host boundary. After 3 months, endothelialization had reached the midsections of the devices, with a thicker collagenous internal capsule. Patches of endothelial-like cells were sharing the luminal surface with thrombotic deposits. However, the wall of the device at the level of the aneurysm was generally poorly healed, with multiple thrombi scattered irregularly over the luminal surface. The polyester fabric was intact except for some filaments that were ruptured adjacent to the sutures and some abrasion caused by the nitinol wires. No evidence of corrosion was found on the nitinol stents. This Anaconda stent-graft has demonstrated its ability to exclude arterial aneurysms. The device used in this study was an experimental prototype, and the manufacturer has incorporated new immobilization features into the model for clinical use. The constituent materials appear to be suitable in terms of biocompatibility, biofunctionality, and short-term durability.

Primary stenting of focal atherosclerotic infrarenal aortic stenoses: long-term results in 13 patients and a literature review.

We conducted this study to investigate the value of primary stent implantation for the endovascular treatment of focal atherosclerotic stenoses of the infrarenal abdominal aorta. The data of 13 patients with a localized complex infrarenal aortic stenosis who underwent primary stenting was retrospectively evaluated. The patients (6 females, 7 males) had a mean age of 57.3 +/- 9.1 years (mean +/- SD). In all patients, the aortic diameter was measured on CT sections, and a self-expanding endoprosthesis was primarily implanted followed by dilatation with single or double balloons. In 3 patients, additional distal stenoses were also endovascularly treated. The procedure was technically successful in all patients. No complications occurred except for 2 minor groin hematomas. During the 43 +/- 23 months (mean +/- SD) follow-up (range: 12-96 months), all stented aortic segments remained patent. Clinical patency was lost in 4 patients, which was due to atherosclerosis or restenosis distal to the aorta. In view of the excellent early and long-term results, we believe that primary stenting should be considered the first line treatment in properly selected patients with focal atherosclerotic infrarenal stenoses of the abdominal aorta.

Endovascular treatment of thoracic disease: patient selection and a proposal of a risk score

Background. Although selection criteria and subgroup analysis are still in the early developmental stages, endovascular treatment of aortic disease has become an alternative to surgery for many patients.Methods. From November 1996 to November 1999, 49 patients were treated with a self-expandable endoprosthesis at our institution. Most patients had acute aortic dissections. Thirteen of these patients did not follow the anatomic selection protocol. We retrospectively analyzed these patients to compare our numerical risk score (which includes clinical and anatomic criteria) between groups with or without success and between groups that followed the anatomic protocol (P) or did not follow the anatomic protocol (E [exception]).Results. Success rates were similar in groups P and E, although mortality rates were higher in group E. Patients from group E had longer procedures and required multiple stents more frequently. The proposed risk score was able to differentiate between groups with or without success, as well as between groups P and E.Conclusions. In order to reduce mortality and morbidity rates, careful selection criteria must be followed when treating patients endovascularly. Although it is time- consuming, using objective criteria can help select patients for endovascular treatment. We propose that patients with a risk score higher than 11 should only undergo percutaneous treatment when they have an unacceptably high surgical risk, and even so only after a detailed discussion of the risks.

Expandable thermal-shaped memory metal esophageal stent: experiences with a new nitinol stent in 129 patients

For most patients with advanced esophagogastric cancer, the only suitable treatment is palliative. 1 Even after surgical resection, approximately 20% of patients have further dysphagia due to tumor recurrence or a stricture at the anastomosis. 2 Surgery and radiation therapy are not commonly used as palliative procedures in China because of high morbidity and mortality rates and the need for prolonged hospitalization. Although laser therapy itself has a low rate of perforation, dilation of the esophagus is necessary before treatment in about 30% of the cases and is associated with a perforation rate of6% to 8%.4 Endoscopic placement of a covered or uncovered expandable esophageal metallic stent tube is a relatively new peroral intubation procedure that increasingly is being used for palliative treatment of esophagogastric strictures.We report our initial experience with a newly developed memory metal self-expanding endoprosthesis made of nitinol in a consecutive series of 129 patients with malignant or benign esophageal obstruction.

Use of an Expandable Ultraflex Stent in the Treatment of Malignant Rectal Stricture

Obstructive colorectal cancer is usually an indication for surgical intervention. For patients with metastatic disease, medical contraindications, or those who refuse surgery, palliation by nonoperative means is necessary. The advent of expandable metallic stents may allow for speedy palliation. We have treated one patient with unresectable colon cancer with a new selfexpanding endoprosthesis made of nitinol (Ultraflex, Microvasive, Watertown, MA, U.S.A.).

Intraureteral Metallic Self-Expanding Endoprosthesis (Wallstent) in the Treatment of Difficult Ureteral Strictures

Intractable and recurrent ureteral stricture presents a continuous challenge to the urologist. We report on 5 patients with severe ureteral stricture who were successfully treated with self-expanding metallic stents. Ureteral stricture occurred at ureteroileal anastomotic sites after neoplasm resection in 2 cases, multiple upper ureteral strictures were related to multiple surgical procedures for correction of bladder exstrophy in 1 and a ureteral kink developed in 1. Treatment with transluminal balloon dilation provided poor results but self-expanding metallic stents were used successfully with no major complications. In the last patient the stent and the overlying ureter were removed due to recurrent reflux; the gross and histological ureteral changes are discussed in detail. The technical approach is described, alternative therapeutic options are considered and pertinent literature is reviewed.

Angioplasty of the terminal aorta: follow-up of 20 patients treated by PTA or PTA with stents

Twenty patients with distal aortic stenosis were treated by PTA for intermittent claudication and, in 3, ‘blue toe’ syndrome. Additionally, a self-expandable endoprosthesis (stent) was inserted into the aorta in three of the patients. The overall primary success rate (including those with a stent) was 100% with all patients becoming free of symptoms. Mean arm-ankle pressure difference decreased from 48 mmHg to 9 mmHg ( P < 0.01). During a median follow-up period of 15 months no patient had recurrence of claudication, embolism, or deterioration of the non-invasive parameters. Thus, PTA seems suitable for treating stenoses of the abdominal aorta, even in the presence of distal micro-embolization. Balloon dilatation, with the addition of stents in resistant cases, offers a valuable alternative to surgery in distal aortic stenosis.

Wallstent self-expanding endoprosthesis in high-risk patients — An alternative to prostatectomy

Wallstent self-expanding endoprosthesis in high-risk patients — An alternative to prostatectomy