nitinol and Aortic-Diseases

In this article we wanted to present an overview of the latest study results, in vitro and in vivo, of the Covered Endovascular Reconstruction of the Aortic Bifurcation or CERAB technique and the C-CERAB or Chimney CERAB for the endovascular treatment of either extensive occlusive aortoiliac or iuxtarenal disease with preservation of visceral arteries; in combination with tips and tricks to facilitate recanalization and revascularization. A review was performed of the literature of the last 5 years regarding the endovascular treatment of aortoiliac and iuxtarenal TASC II C& D lesions with covered balloon expandable stents. Furthermore we did a retrospective analysis of our most special techniques to achieve a successful interventional recanalization of these challenging lesions. Both the in vitro and the in vivo studies pointed out that there exists an important benefit of the CERAB configuration with excellent patency rates at one and two years in combination with very low mortality and morbidity, when compared to other techniques. Also the C-CERAB variant seems to be a feasible and safe option; 100% technical success; to deal with iuxtarenal or extensive aortic occlusive disease together with the safeguarding of visceral arteries. The CERAB and C-CERAB techniques may change the treatment algorithm of extensive aortoiliac occlusive disease in the near future and appears to be a safe and feasible alternative with promising results, together with a more anatomical and physiological reconstruction of the aortic bifurcation, being a valid alternative for surgery and/or kissing stents. A few critical issues still need to be solved, such as cost-effectiveness, patient selection, fine-tuning of the technique and defining the optimal medical support.

Topics: Alloys; Aorta, Abdominal; Aortic Diseases; Arterial Occlusive Diseases; Blood Vessel Prosthesis Implantation; Cost-Benefit Analysis; Endovascular Procedures; Equipment Design; Humans; Iliac Artery; In Vitro Techniques; Patient Selection; Stents; Vascular Patency

Coral reef aorta (CRA) is a rare condition, characterised by rock-hard calcification of the juxta-renal and supra-renal aorta with luminal encroachment causing significant stenosis of the aorta and its branches. It usually presents as resistant hypertension, renal dysfunction, mesenteric ischaemia, limb claudication or embolic manifestations. Although surgical thrombo-endarterectomy along with bypass graft to the affected visceral arteries remains the cornerstone of treatment, it is associated with considerable mortality and morbidity, especially in patients with pre-existing comorbidities. Here we report an elderly female of resistant hypertension, who had successful endovascular aortic stenting using a non-graft self-expanding stent. Her blood pressure dramatically improved following endovascular management. In comparison to the conventional surgical approach, endovascular stenting can be an alternative, less invasive approach in selected CRA patients.

Topics: Aged; Alloys; Aortic Diseases; Computed Tomography Angiography; Diabetic Angiopathies; Female; Humans; Hypertension; Stents; Tomography, X-Ray Computed; Treatment Outcome; Vascular Calcification

Objectives Various configurations of kissing stent (KS) configurations exist and patency rates vary. In response the covered endovascular reconstruction of the aortic bifurcation configuration was designed to minimize mismatch and improve outcome. The aim of the current study is to compare geometrical mismatch of kissing stent with the covered endovascular reconstruction of the aortic bifurcation configuration in vivo. Methods Post-operative computed tomographic data and patient demographics from 11 covered endovascular reconstruction of the aortic bifurcation and 11 matched kissing stent patients were included. A free hand region of interest and ellipse fitting method were applied to determine mismatch areas and volumes. Conformation of the stents to the vessel wall was expressed using the D-ratio. Results Patients were mostly treated for Rutherford category 2 and 3 (64%) with a lesion classification of TASC C and D in 82%. Radial mismatch area and volume for the covered endovascular reconstruction of the aortic bifurcation group was significantly lower compared to the kissing stent configuration ( P < 0.05). The D-ratio did not significantly differ between groups. Measurements were performed with good intra-class correlation. There were no significant differences in the post-procedural aortoiliac anatomy. Conclusions The present study shows that radial mismatch exists in vivo and that large differences in mismatch exist, in favour of the covered endovascular reconstruction of the aortic bifurcation configuration. Future research should determine if the decreased radial mismatch results in improved local flow profiles and subsequent clinical outcome.

Topics: Aged; Alloys; Angioplasty, Balloon; Aortic Diseases; Aortography; Computed Tomography Angiography; Endovascular Procedures; Female; Humans; Iliac Artery; Male; Middle Aged; Netherlands; Peripheral Arterial Disease; Prosthesis Design; Self Expandable Metallic Stents; Treatment Outcome

Endovascular therapy for aortoiliac (AI) lesions using stents is widely accepted. However, the long-term outcome of 2 different types of nitinol stents for AI lesions is unknown. The aim of this study was to examine the long-term outcome of the SMART and Luminexx nitinol stents for the treatment of de novo AI lesions.. This study was a multicenter retrospective analysis of a prospectively maintained database. The study enrolled consecutive patients undergoing primary stenting for de novo AI artery stenosis between January 2005 and December 2009. A total of 1503 lesions in 1229 patients treated with SMART or Luminexx primary stenting were enrolled. The primary end point was primary patency, secondary end points were the primary assisted patency, secondary patency, and major adverse limb events (MALEs), which included major amputation and major reintervention. To minimize the differences between the groups, a propensity score matching analysis was performed, and 284 lesions per group were analyzed to identify outcomes.. After the propensity score matching analysis, the lesion length was 60 ± 37 and 57 ± 31 mm (P = .275), and the reference vessel diameter was 8.2 ± 1.5 and 8.3 ± 1.5 mm (P = .482) in the SMART and Luminexx groups, respectively. The primary patency at 3 years was not significantly different between the groups (83.5% vs 82.2%, P = .842, respectively). The assisted primary patency and secondary patency rates were also not significantly different (91.7% vs 93.2%, P = .340, 99.2% vs 98.8%, P = .922). In addition, the MALE rate was not significantly different between the groups (98.3% vs 97.3%, P = .821).. The current data suggest that the use of nitinol stents for the AI artery provided good long-term patency and freedom from MALE for 3 years of follow-up, regardless of whether SMART or Luminexx stents were used.

Topics: Aged; Aged, 80 and over; Alloys; Amputation, Surgical; Aortic Diseases; Arterial Occlusive Diseases; Constriction, Pathologic; Databases, Factual; Endovascular Procedures; Female; Humans; Iliac Artery; Japan; Kaplan-Meier Estimate; Limb Salvage; Logistic Models; Male; Middle Aged; Propensity Score; Prosthesis Design; Recurrence; Retrospective Studies; Risk Factors; Stents; Time Factors; Treatment Outcome; Vascular Patency

To report the bench-top evaluation and initial clinical use of an instrument for on-site fenestration of aortic stent-grafts.. A stainless steel thermal cautery instrument was designed to create circular stent-graft fenestrations from 3 to 10 mm in diameter. Three operators independently bench-tested the instrument on thoracic stent-graft samples to evaluate size, shape, location, and quality of fenestrations created. For clinical use, on-site fenestration was performed 2 days before the endovascular procedure in a sterile room without access to supplemental oxygen. A fenestrator 1 or 2 mm smaller in diameter than the target vessel was used; the edges of the fenestrations were strengthened using flexible radiopaque nitinol wire. The aortic stent-graft was then re-sheathed and sterilized for added safety. Eighteen patients (17 men; mean age 51 years, range 18-80) with a variety of thoracic and juxtarenal pathologies were treated using Zenith TX2, Valiant Captivia, Zenith AAA, and Endurant stent-grafts modified in this manner.. After successful bench testing, the instrument was used to create 34 fenestrations in aortic stent-grafts deployed in the 18 patients. Size and location of fenestrations obtained were as desired. Subsequent catheterization of the fenestration/target vessel and covered stent deployment were successfully achieved in 31 (91%) fenestrations; 2 fenestrations had type III endoleaks and 1 fenestration was unused. There was no perioperative mortality, stroke, embolization, vessel dissection, renal failure, or graft infection. Follow-up to 1 year in the majority of patients has revealed no new fenestration-related problems.. This simple-to-use instrument makes on-site creation of aortic stent-graft fenestrations easy, accurate, and precise. The instrument is inexpensive, robust, and easily sterilized.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Alloys; Aorta, Abdominal; Aorta, Thoracic; Aortic Diseases; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Cautery; Endoleak; Endovascular Procedures; Equipment Design; Feasibility Studies; Female; Humans; Male; Materials Testing; Middle Aged; Prosthesis Design; Stainless Steel; Stents; Time Factors; Treatment Outcome; Young Adult

Thoracic endovascular aortic repair is increasingly becoming the standard treatment of many thoracic aortic pathologies. New reliable and accurate stent grafts are emerging to widen the endovascular treatment options. We report the results of RELAY (Bolton Medical, Barcelona, Spain) in the large RELAY Endovascular Registry for Thoracic Disease (RESTORE) European registry.. RESTORE is a multicenter, prospective European registry involving 22 centers in seven European countries. The RELAY device is composed of a stent graft (self-expanding nitinol stents and a polyester vascular graft) and a delivery device specifically designed for the thoracic aorta. Included were acute and elective patients presenting with a variety of pathologies (aneurysms, dissections, ulcerations, intramural hematomas, pseudoaneurysms) and lesions in different aortic and anatomic locations (ascending, arch, descending and thoracoabdominal).. The registry enrolled 304 patients from April 2005 to January 2009. All-cause mortality at 30 days was 7.2%. Freedom from all cause mortality and freedom from device- and procedure-related mortality at 2 years were 78.5% and 95.9%, respectively. An average of 1.26 graft components were used per patient, with a technical success of 97.7% irrespective of the etiology. Early endoleak rate was 4.6%. Perioperatively, stroke and paraplegia were registered in 1.6% and 2.0%, respectively.. The results of RESTORE support the safety of thoracic endovascular aortic repair with the RELAY stent graft, even in acute and complicated situations. The device was highly efficient in angulated aortic anatomies, with acceptable mortality and a low rate of neurologic complications.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Alloys; Aorta, Thoracic; Aortic Diseases; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Endoleak; Endovascular Procedures; Europe; Female; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Paraplegia; Polyesters; Prospective Studies; Prosthesis Design; Registries; Risk Assessment; Stents; Stroke; Time Factors; Treatment Outcome; Young Adult

The histologic response to self-expanding stent implantation into advanced atherosclerotic lesions has not been systematically investigated. We tested the hypothesis of whether gradual expansion of advanced atherosclerotic plaques by self-expanding stents would be an appropriate method to seal atherosclerotic lesions without causing plaque disruption as is usually observed with balloon-expandable stents.. Twelve New Zealand white rabbits were fed an atherogenic diet (1% cholesterol) followed by arterial denudation and injection of washed autologous erythrocytes. Nitinol self-expanding stents of two different stent designs and strengths (n=12 for SX and n=12 for Micro-SX) were implanted into the previously formed lesions within the abdominal aorta six weeks following injection of erythrocytes. Four weeks following stent implantation, animals were sacrificed, specimens harvested and processed for histology. Histomorphometry was performed on stented and adjacent non-stented regions. Atherosclerotic lesions were composed of foam cells, cholesterol clefts and necrotic plaque. While SX stents showed an unfavourable outcome with respect to vessel remodelling and the percentage of uncovered stent struts, Micro-SX stents had fewer uncovered stent struts, less positive remodelling and less plaque injury.. Nitinol Micro-SX self-expanding stents might be a valuable approach to seal high risk atherosclerotic lesions.

Topics: Alloys; Animals; Aorta, Abdominal; Aortic Diseases; Atherosclerosis; Blood Vessel Prosthesis; Endothelium, Vascular; Prosthesis Design; Rabbits; Stents

Although technological improvements continue to advance the designs of aortic stent grafts, miniaturization of the required delivery systems would allow their application to be available to a wider range of patients and potentially decrease the access difficulties that are encountered. We performed this feasibility study to determine if thin-film NiTi (Nitinol) could be used as a covering for stent grafts ranging from 16 mm to 40 mm in diameter. Specifically, we wished to determine the profile reduction attainable and improve the flexibility of our design.. Using a novel hot-sputter deposition technique, we created sheets of thin-film NiTi (TFN) with a tensile strength of >500 Megapascal (MPa) and thickness of 5-10 microns. TFN was used to cover stents, which were then deployed in vitro. Patterned thin film was fabricated via a lift-off technique; grafts were constructed with stents ranging from 16-40 mm and deployed in a pulsatile flow system from the smallest diameter polymer tubing into which the stent and TFN would fit. The bending/stiffness ratio vs similar sized expanded polytetrafluoroethylene (ePTFE)-covered stents was also determined.. TFN was created in both non-patterned and patterned forms, with a tensile strength of >100 MPa for the latter. We created devices that were successfully deployed via delivery systems half the size of fabric-covered stent grafts (ie, the 16 mm stent graft that originally was delivered via a 16French (F) system was reduced to 8F, and the 40 mm stent graft delivered via a 24F system was reduced to 12F). No migration of the devices was observed with deployment in both straight and curved tubing, which was sized so that the stent grafts were oversized by 20%. Both forms of the thin-film were noted to be more flexible than the same sized ePTFE stent graft, and the patterned graft had an additional 15-30% flexibility vs the non-patterned film.. These in vitro results demonstrate the feasibility of TFN for covering stent grafts designed for placement in the aorta. The delivery profile can be significantly reduced across a wide range of sizes, while the material remained more flexible than ePTFE.

Topics: Alloys; Aortic Diseases; Biomechanical Phenomena; Blood Vessel Prosthesis; Coated Materials, Biocompatible; Feasibility Studies; In Vitro Techniques; Materials Testing; Microscopy, Electron, Scanning; Polytetrafluoroethylene; Prosthesis Design; Pulsatile Flow; Stents; Surface Properties; Tensile Strength

Reducing the negative side effects associated with extracorporeal circulation is the major advantage of off-pump revascularization. However, side clamping of a calcified aorta for proximal anastomoses can cause emboli, resulting in neurologic damage. This problem has been addressed by introducing a mechanical anastomosis device (Symmetry, St Jude Medical) that allows vein-to-aorta anastomosis without manipulating the aorta. This report describes our experience with this device.. Between June 2001 and April 2002, 77 connectors (1.3 per patient) were deployed in 61 patients (51 men and 10 women; mean age, 68 +/- 8.6 years) undergoing off-pump coronary artery bypass grafting or beating-heart revascularization. Intraoperative quality assessment included transit-time flow measurement (Medistim) and indocyanine green-based angiography (Spy, Novadaq).. The surgeons were meticulously trained in loading of the device. No postoperative neurologic deficits were detected. Fifty-three patients had an uneventful course. However, 8 (13.1%) patients with 12 implanted connectors were symptomatic within 8 months (1 day to 8 months). Angiography revealed significant (95%) stenosis or even occlusion of the proximal vein-to-aorta anastomosis at the level of all connectors. Four patients underwent reoperation (2 dilated-stented and 2 treated with drugs).. On the basis of these observations, the routine use of the connector was halted at our institution. At the moment, the use of this therapy is reserved for patients with severely calcified aortas with no technical alternative. Further investigations appear necessary to evaluate the clinical patterns of this otherwise promising technology.

Topics: Aged; Alloys; Anastomosis, Surgical; Aorta; Aortic Diseases; Calcinosis; Coronary Angiography; Coronary Artery Bypass; Equipment Failure; Female; Graft Occlusion, Vascular; Humans; Male; Postoperative Complications; Veins

Metallic stents in small vessels go along with a significant risk of restenosis and reocclusion. Different models of stents and covering materials have been purported to prevent intraluminal neointimal proliferation by cover-based closure of the spaces in the wire mesh.. Tantalum stents covered with polyethylacrylate/polymethylmethacrylate (PEM) were implanted in the infrarenal aorta of six New Zealand white rabbits by aortotomy and compared with eight rabbits treated with uncovered tantalum stents. For deployment, covered and uncovered stents necessitated a 7-French (F) and 5-F sheath, respectively. In addition, nine human patients with arteriosclerotic lesions of the superficial femoral arteries (stenosis > 5 cm or total occlusion) were treated percutaneously with a Dacron-covered nitinol vascular stent via a 9-F sheath. Patients were followed for a mean of 13.5 months, and control angiography was performed after 6 months.. Experimental placement of the tantalum Wiktor stent was feasible technically in all cases. Five of six stents covered with PEM were occluded 3 days after placement despite the intravenous use of heparin and aspirin. In the group with uncovered stents, no area of stenosis greater than 10% was observed. There was a neointimal layer of 89 +/- 68 microns around the stent wires. Stent placement was successful in all patients. In four patients, a hyperergic reaction occurred, resulting in noninfectious periarteriitis. This complication was treated successfully with nonsteroidal antiinflammatory drugs. The primary patency was 50%, and the secondary patency (after application of a second covered stent in two patients) was 63%.. The uncovered stent induces little neointimal proliferation around the stent wires. The insertion of stents covered with PEM into the rabbit aorta was accompanied by a strong thrombotic reaction, despite sufficient anticoagulation. Dacron-covered nitinol stents showed a surprisingly high restenosis rate after 9 months of follow-up. Further research concerning the in vivo properties of new covering materials is mandatory before routine vascular clinical application.

Topics: Aged; Alloys; Animals; Aorta, Abdominal; Aortic Diseases; Arteriosclerosis; Biocompatible Materials; Constriction, Pathologic; Equipment Design; Female; Femoral Artery; Humans; Iliac Artery; Male; Polyethylene Terephthalates; Polymethacrylic Acids; Rabbits; Recurrence; Stents; Tantalum; Thrombosis