endovascular stents
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Author(s):  
Joel Scott ◽  
Darrel Doman ◽  
Clifton Johnston

Stent migration due to haemodynamic drag remains the primary cause of type I endoleak, potentially leading to aneurysm rupture. The prevalence of migration and endoleak can be partially attributed to deficiencies in stent-graft radial spring design and a lack in understanding of the mechanical properties of endovascular stents. A converged finite element model of a custom radial extensometer was developed, fit, and validated using experimental results for bare stent wire (”uncovered”) with outer diameter of 12 mm stent. During stent constriction to 50 % of the original cross- sectional area, a comparison of experimental and modeled results produced an r2 value of 0.946, a standard error of 0.099 N, and a mean percent error of 1.69 %. This validated finite element model can be used to analyze the mechanisms responsible for radial force generation in 316L stainless steel self-expanding endovascular stents, as well as to evaluate new stent designs.


Medicina ◽  
2021 ◽  
Vol 57 (6) ◽  
pp. 620
Author(s):  
Muzammil H. Syed ◽  
Mark Wheatcroft ◽  
Danny Marcuzzi ◽  
Hooman Hennessey ◽  
Mohammad Qadura

The aim of this paper is to share our experience in managing a patient with Klebsiella pneumoniae mycotic abdominal aortic aneurysm who was also infected with COVID-19. A 69-year-old male was transferred to our hospital for the management of an infra-renal mycotic abdominal aortic aneurysm. During his hospital course, the patient contracted severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). He was intubated due to respiratory distress. Over a short period, his mycotic aneurysm increased in size from 2.5 cm to 3.9 cm. An emergency repair of his expanding aneurysm was achieved using our previously described protocol of coating endovascular stents with rifampin. The patient was managed with a rifampin-coated endovascular stent graft without any major complications. Postoperatively, the patient did not demonstrate any neurological deficits nor any vascular compromise. He remained afebrile during his postoperative course and was extubated sometime thereafter. He was then transferred to the ward for additional monitoring prior to his discharge to a rehab hospital while being on long-term antibiotics. During his hospital stay, he was monitored with serial ultrasounds to ensure the absence of abscess formation, aortic aneurysm growth or graft endoleak. At 6 weeks after stent graft placement, he underwent a CT scan, which showed a patent stent graft, with a residual sac size of 2.5 cm without any evidence of abscess or endoleak. Over a follow-up period of 180 days, the patient remained asymptomatic while remaining on long-term antibiotics. Thus, in patients whose surgical risk is prohibitive, endovascular stent grafts can be used as a bridge to definitive surgical management.


2021 ◽  
Vol 12 (2) ◽  
pp. 33
Author(s):  
Raluca Ion ◽  
Gaëtan Cabon ◽  
Doina-Margareta Gordin ◽  
Elena Ionica ◽  
Thierry Gloriant ◽  
...  

Titanium alloys are widely used for biomedical applications due to their good biocompatibility. Nevertheless, they cannot be used for balloon expandable stents due to a lack of ductility compared to cobalt-chromium (Co-Cr) alloys and stainless steels. In this study, a new highly deformable Ti-16Nb-8Mo alloy was designed for such an application. However, the biological performance of a stent material is strongly influenced by the effect exerted on the behavior of endothelial cells. Therefore, the cellular responses of human umbilical vein endothelial cells (HUVECs), including morphological characteristics, cell viability and proliferation, and functional markers expression, were investigated to evaluate the biocompatibility of the alloy in the present study. The in vitro results demonstrated the suitability of this alloy for use as endovascular stents.


2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
K Daga ◽  
B Chua ◽  
M Taneja

Abstract Spontaneous renal artery dissection and acute renal infarcts are rare occurrences and often misdiagnosed in clinical practice. We present four male patients, between 30-50 years of age, who have no underlying cardiac conditions, hypertension, or diabetes mellitus. They presented with abdominal/loin/flank pain due to spontaneous renal artery dissection and were all treated with endovascular stenting. Two patients had renal artery fibromuscular dysplasia, confirmed by CT angiogram, a rare pathology which is reported in literature to mostly affect women. All four patients recovered fully from the operation, with no post-operative complications noted. These patients were post-operatively managed medically with anti-platelet therapy for two years and did not experience any post-procedural complications at their 24-month follow up. Classically visceral artery dissection can be managed by anti-platelet therapy alone, however fibromuscular dysplasia can cause spontaneous dissection with renal infarcts and this requires urgent treatment with endovascular stents. Further research is needed on the post-procedural medical management guidelines.


2021 ◽  
Vol 12 ◽  
Author(s):  
Wei Wei ◽  
Chong Song ◽  
Xuqin Li ◽  
Dianshi Jin

Objective: To investigate the clinical value of CT perfusion (CTP) imaging in vertebral artery stenosis stenting, so as to provide the basis for preoperative and postoperative evaluation. Ninety-seven patients with vertebral artery stenosis were accepted for endovascular stenting between Jan 2016 and Jan 2020. CT angiography, Digital Subtraction Angiography, and CTP were performed pre-operation and post-operation. The cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transmit time (MTT) between the health and affected sides were analyzed statistically, and the imaging results pre- and post-operation were evaluated. The stenosis was relieved by endovascular stents in all 97 patients without serious complications. The abnormal perfusion was observed in 66 patients (68%). The differences in CBF and MTT between the diseased side and healthy side were statistically significant (P < 0.05). Compared with the preoperative imaging, the postoperative CTP was improved in 59 patients (89%). The differences in CBF and MTT between pre-operation and post-operation were statistically significant (P < 0.05). But there was no significant difference in CBV. CTP can sensitively reflect the perfusion of brain, and can also be used for preoperative and postoperative evaluation of vertebral artery stenting. It may be helpful as an adequate indicator of vertebral artery stenosis stent surgery.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yutaro Kato ◽  
Atsushi Sugioka ◽  
Masayuki Kojima ◽  
Junichi Yoshikawa ◽  
Yoshinao Tanahashi ◽  
...  

Abstract Background Acute obstruction of the hepatic vein (HV) or the portal vein (PV), particularly when it occurs during liver surgery, is potentially fatal unless repaired swiftly. As surgical interventions for this problem are technically demanding and potentially unsuccessful, other treatment options are needed. Case presentation We report two cases of acute, surgically uncorrectable HV or PV obstruction during liver resection or living donor liver transplantation (LDLT), which was successfully treated with urgent intraoperative placement of endovascular stents using interventional radiology (IVR). In Case 1, a patient with colonic liver metastases underwent a non-anatomic partial hepatectomy of the segments 4 and 8 with middle hepatic vein (MHV) resection. Additionally, the patient underwent an extended right posterior sectionectomy with right hepatic vein (RHV) resection for tumors involving RHV. Reconstruction of the MHV was needed to avoid HV congestion of the anterior section of the liver. The MHV was firstly reconstructed by an end-to-end anastomosis between the MHV and RHV resected stumps. However, the reconstruction failed to retain the HV outflow and the anterior section became congested. Serial trials of surgical revisions including re-anastomosis, vein graft interposition and vein graft patch-plasty on the anastomotic wall failed to recover the HV outflow. In Case 2, a pediatric patient with biliary atresia underwent an LDLT and developed an intractable PV obstruction during surgery. Re-anastomosis with vein graft interposition failed to restore the PV flow and elongated warm ischemic time became critical. In both cases, the misalignment in HV or PV reconstruction was likely to have caused flow obstruction, and various types of surgical interventions failed to recover the venous flow. In both cases, an urgent IVR-directed placement of self-expandable metallic stents (SEMS) restored the HV or PV perfusion quickly and effectively, and saved the patients from developing critical conditions. Furthermore, in Cases 1 and 2, the SEMS placed were patent for a sufficient period of time (32 and 44 months, respectively). Conclusions The IVR-directed, urgent, intraoperative endovascular stenting is a safe and efficient treatment tool that serves to resolve the potentially fatal acute HV or PV obstruction that occurs in the middle of liver surgery.


2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Sushma Krishna ◽  
Sumanth Kaiwar ◽  
AmrithlalA Mascarenhas ◽  
Adarsh Raghurama

2021 ◽  
Vol Volume 16 ◽  
pp. 213-221
Author(s):  
Franz Wegner ◽  
Anselm von Gladiss ◽  
Julian Haegele ◽  
Ulrike Grzyska ◽  
Malte Maria Sieren ◽  
...  

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