Stent design considerations pdf

Strut thickness was the focus of many clinical studies with thicker struts causing. Three hundred ninety patients underwent cas, with 451 vessels treated. Efforts to optimise one characteristic of stent design may have detrimental effects on another. This overview looks at current practices and problems related to stents, along with clinical and economic considerations. This chapter outlines the design components of the axios stent and its delivery system. Much research has been conducted to the pathophysiology and treatment of in stent restenosis. Pdf a stent is a device designed to restore flow through constricted arteries. Lumenapposing metal stents for endoscopic ultrasoundguided drainage of pancreatic fluid collections. The compatibility of bare metal stents is due both to the stent material and design, while des effectiveness is also affected by polymers used for coating and the antiproliferative drugs released.

In press, corrected proof what are corrected proof articles. Important stent design considerations article pdf available in annals of biomedical engineering 442 july 2015 with 165 reads. Enhanced closed cell design the closed cells were redesigned allowing the stent to better expand and contract in vessel tortuosity, optimizing wall apposition 3. Stent design for a percutaneous heart valve a major qualifying project submitted to the faculty of worcester polytechnic institute in partial fulfillment of the. It has found widespread acceptance as a material of choice for medical implants and devices 4.

Boston scientific is a leading developer of advanced stent technologies, and remains committed to high quality standards and collaboration with physicians. Topological and parametric optimization of stent design based on numerical methods. Background the introduction of angioplasty led to the development of a completely new approach to treat cad. They resist outside forces with a significantly higher radial resistive force.

Strut spacing, thickness, luminal protrusion, and malapposition were. Recognize the imaging appearances of ureteral stents and the most common problems associated with them. Layout design of a bistable cardiovascular stent using. The choice of lumen diameter is influenced by several considerations related to local anatomy size and location of target and bowel lumens and therapeutic intent. Material considerations for development of 3d printed. A stent is a device designed to restore flow through constricted arteries. It would be valuable to investigate the deformation of unstented diseased arteries under flexion and then assess the changes when a stent is implanted. Design considerations of the axios stent and electrocautery enhanced delivery system. The biodurability of covering materials for metallic stents in a bile flow phantom bang et. Effects of stent design parameters on normal artery wall mechanics. Improvements have led to improvements in the design and conformation of metallic or resorbable structures, with an adequate balance between trackability and radial force, the development of antiproliferative drugs and the polymers to control release and allow. The pump and circuit were adjusted to generate a pulsatile pressure of 110150 mm hg. Poncet memry corporation, 4065 campbell avenue menlo park, ca 94025 usa tel 650463 3416 fax 650463 3456 email. The axios stent was manufactured in a variety of lumen diameters, ranging from 6 mm to 20 mm.

However, stent platform design and its clinical implications have now. The spaxus stent taewoong medical, gyeonggido, south korea, a novel lumenapposing metal stent, was developed for eusguided drainage procedures and has shown promising technical and clinical success rates for pancreatic fluid collections, bile duct, or gallbladder drainage. In this presentation stent material, cutting techniques, finishing techniques, and inspection techniques are looked into. Vo2, martin meere3, sean mckee1, christopher mccormick4 abstract in this paper we provide the. Hemodynamics in idealized stented coronary arteries. Pdf the ideal stent must fulfil a broad range of technical requirements. Although the use of stents in coronary intervention procedures are adopted worldwide, several patients exhibits instent restenosis isr due to the thick accumulation of vascular tissue after stent being placed 4,6,10,11, lead. Safety of an aspirinalone regimen after intracoronary. These tubular scaffold devices are delivered to the afflicted region and deployed using minimally invasive techniques. A survey of stent designs university of southampton. In this paper we provide the first model of drug elution from polymerfree arterial drugeluting stents.

Complications of ureteral stent placement1 learning objectives for test 1 after reading this article and taking the test, the reader will be able to. Supera stent demonstrated excellent 1 yr patency and 3 yr. Endoscopic ultrasonographyguided gallbladder drainage using lumenapposing metal stents. Jan 06, 2012 selfexpanding nitinol stents material and design considerations. Although the use of stents in coronary intervention procedures are adopted worldwide, several patients exhibits in stent restenosis isr due to the thick accumulation of vascular tissue after stent. Few trial studies have been enumerated in the context of utilization of a ureteral stent symptom questionnaire and various stent models to. Carotid endarterectomy cea is one of the most frequently performed operations in the united states. Stent induced hemodynamic changes in the coronary arteries are associated with higher risk of adverse clinical outcome. Stents may be selfexpanding or balloon expandable and can be made from various materials including stainless steel, elgiloy, tantalum, nitinol or polymers. An overview of superelastic stent design duerig, tolomeo. A stent design pyramid is presented, which breaks the differentiating aspects. The art of stent laser processing abstract precision laser processing of medical stents is a current manufacturing method utilized around the world. This article focuses on the features of stent design.

Design considerations of the novel lumenapposing metal stent. Although iss rates are 1020% in selected patients, we now stent total occlusions, saphenous vein bypass grafts, both angioplasty. Stents must be securely crimped onto the delivery balloon and, in this form, must have a low profile and be sufficiently flexible to facilitate deliverability to the lesion site without distortion or displacement. Given the heterogeneity of presented studies and the data collected, several key design considerations, outlined in table iii, become evident for future studies.

Duda2 1nitinol devices and components, fremont, ca usa 2dept of diagnostic radiology, university of tuebingen, tuebingen, germany summary over 100 different stent designs are currently being marketed or are in evaluation for vascular and nonvascular indications. Some design considerations for polymerfree drugeluting stents. May 12, 2008 the goal of this research was to investigate mathematically design considerations for an improved stent that can reduce these negative effects. Technical considerations for nonclinical assessment of. The generalised model is capable of predicting drug release from a number of polymerfree systems including those that exhibit nanoporous. Hussain bachelor of science university of south carolina, 20 submitted in partial fulfillment of the requirements for the degree of master of science in biomedical engineering college of engineering and computing university of south carolina 2015. Secondary considerations contralateral limb coverage iiv coverage all these require different stent. This was accomplished through the construction of a onedimensional numerical model for the fluid mechanics of the artery that was implemented using fea and a combination of weno and rungekutta methods. The axios stent is made of nitinol wire and is completely covered with a silicone membrane. The distance between the 2 flanges is 10 mm, and the diameters are 10, 15, or 20 mm. Nitinol medical device design considerations philippe p. Applications and practice management considerations.

Material considerations for development of 3d printed bronchial and tracheal stents by nidah m. Download pdf a survey of stent designs structural and diffusional effects of hydroge. Drugeluting stents des were designed to minimise neointimal hyperplasia and reduce repeat revascularisation, but an increased risk of late stent thrombosis st was observed with the first generation of devices. New des have been developed to ensure good acute and longterm results while minimising stent thrombosis rate. Wallflex esophageal stents fully and partially covered self expanding metal stents place your trust in over 20 years of research and development. A numerical and experimental analysis of cardiovascular stent. Dec 08, 2016 the wide range of design considerations for balloon catheters can be can be daunting.

Over 100 different stent designs are currently being marketed or are in evaluation for. These found that strut spacing,14 stent connectors,36 strut peak angle,12 and strut thickness15 were all important hemodynamic considerations in stent design. On august 18, 2015, fda issued the final guidance select updates for nonclinical engineering tests and recommended labeling for intravascular stents and. Pdf the introduction and widespread adoption of drugeluting stents. Current considerations in venous obstruction and stenting. Discuss the characteristics of the ideal ureteral stent. Pdf nitinol nickeltitanium alloys exhibit a combination of properties which make these. Apr 28, 2014 however, stent platform design and its clinical implications have now come back to the fore. Recapturable stent the closed cell design allows for deployment and. The dynamics of venous stent design stephen black consultant vascular surgeon clincial lead for venous and lymphoedema surgery guys and st thomas hospitals london. Hybrid or design is influenced and regulated by several federal, state, and local codes. There has been a great evolution in the development of coronary stents in order to avoid both restenosis and thrombosis. Des are combination products composed of a medicinal products and medical devices and since the medicinal products. Mazzaccaro d, stegher s, muzzarelli l, malacrida g, nano g, the carotid wallstent for the endovascular treatment of carotid artery stenosis, interdisciplinary neurosurg 10.

Now at body temperature, the stent is superelastic. Stents have also been placed to treat fistulas and leaks. Perioperative management of patients with coronary stents. Pdf effects of stent design parameters on normal artery. Tools to assist the multidisciplinary design team include the facility guidelines institute fgi guidelines for design and construction documents and the association of perioperative registered nurses aorn guidelines for perioperative practice. Stent design and placement stent design and materials are critically important, but a thorough discussion of these features is beyond the focus of this article. At its simplest form, a reinforced catheter design is composed of an inner liner layer, a central reinforcing layer, and an outer polymeric overlayer. Jul 16, 2015 stent induced hemodynamic changes in the coronary arteries are associated with higher risk of adverse clinical outcome. Backgroundstent thrombosis is an infrequent complication of intracoronary stenting that often has devastating clinical.

The first metallic stent, used by canfield and norton in 1933, was made of silver. Selfexpanding nitinol stents material and design considerations. The generalised model is capable of predicting the drug release from a number of polymerfree systems including those that exhibit nanoporous, nanotubular and smooth surfaces. Design considerations for studies of the biomechanical environment of the femoropopliteal arteries farzana ansari, ms,a lindsay k.

After deployment, they position themselves against the vessel wall with a low, chronic outward force. Nitinol nickeltitanium alloys exhibit a combination of properties which make these alloys particularly suited for selfexpanding stents. The design allows for better flexibility and maneuverability. Kink and crush resistance are directly proportional to superelasticity therefore one must ensure that the application or design fit well within the superelastic temperature range. Design considerations for studies of the biomechanical environment of the femoropopliteal arteries farzana ansari. The stent is dumbbell shaped in order to oppose and anchor the gastrointestinal lumen to the wall of the drain. The ideal stent must fulfil a broad range of technical requirements. This new stent has an open cell design composed of parallel struts of laser cut 316l stainless steel.

We derive analytical solutions which allow us to easily determine the important parameters that control the drug. Pdf long and short of optimal stent design researchgate. Design considerations for studies of the biomechanical. Technical considerations for nonclinical assessment of medical. Finally, the longer the stent length, the more prone the stent is to clogging. The shortcomings of tubular stents when applied off label for eusguided transluminal applications inspired the development of the lumenapposing metal stent lams. Stents must have sufficient radial strength to prop the diseased artery open. Stent design is a highly complex engineering task that must take into account a multitude of performance requirements. Clearly this has important implications to recoil that. Pdf some design considerations for polymerfree drug. Some of these properties cannot be found in engineering materials used for stents presently. Drug eluting stents des have turned up as a potential solution for restenosis.

For example, scheinert et al3 reported an from the department of mechanical engineering, university of california. The purpose of this study was to evaluate the impact of stent design on wall shear stress wss, time average wss, and wss gradient wssg, in idealized stent geometries using computational fluid dynamics. Stent design has markedly improved over the last 22 years since the first bms was fda approved while there were differences in early stent design and performance, current bms and des are all quite good specific clinical scenarios require specific stentsensure you are familiar with what is on your shelf. Rajah g, narayanan s, rangelcastilla l, update on flow diverters for the endovascular management of cerebral aneurysms, neurosurg focus 42.

The design was performed in collaboration with nitinol stent manufacturers. Nitinol stents are manufactured to a size slightly larger than the target vessel size and delivered constrained in a delivery system. This has occurred for numerous reasons, but has primarily been driven by the need for modern stents to perform well in increasingly demanding clinical scenarios. Catheter design guidelines from teleflex medical oem. Openversus closedcell stent comparison serves as a good example of a chief analysis because it is entirely possible to design an opencell stent with a cell size smaller than that of a closedcell stent, thus rendering the distinction near meaningless. Pdf hemodynamics in idealized stented coronary arteries. Prevention and management of longitudinal deformation.

Murphy, md the use of iliac vein stents for the treatment of iliofemoral or iliocaval obstruction has revolutionized the treatment of patients with chronic venous disease. Stent design for a percutaneous heart valve worcester. The developments in cardiovascular stent design over the last 30 years have been truly. The first types of stents used were bare metal stents bmss, composed of a variety of metals andor alloys such as stainless steel, cobaltchromium and tantalum for balloonexpandable stents, or nitinol nickeltitanium alloy for selfexpanding stents 5. Design considerations of the novel lumenapposing metal stents nitis spaxus. Design considerations of the axios stent and electrocautery. Design considerations of the novel lumenapposing metal. Many of the engineering considerations in stent design were adopted to improve the global acceptability of the device, rather than making a stent design for a speci. Some design considerations for polymerfree drugeluting. Suffice it to say that various metals, silicone, polyester, and mixed hybrid materials have been used. Aug 14, 2018 carotid artery stenting cas is a minimally invasive technique for treating carotid artery disease. The following illustrations show a comparison of conventional design versus a design that incorporates planning principles and consideration for the natural site features.

The most common indication for stenting is lumen recanalization to relieve an obstruction due to a malignant or benign stricture. Inner layer liners when selecting a liner material, it is essential to consider both the benefits of a material and its design considerations. Nonclinical engineering tests and recommended labeling. Tools considered include lasers, optics, positioning systems, and cnc programs. The supera stent is known for the excellence of its clinical outcomes during percutaneous transluminal angioplasty pta procedures, since this peripheral stent has been studied in more than 2,000 patients and 17 studies worldwide. Conventional luminal stents are tubular in form, conceived for coaxial placement within a lumen. Design considerations such as strut thickness, cell design and mechanical properties have been steadily. Stent positioning marker a fluoroscopic guide helps provide precise deployment at the aneurysm neck 2. Medicine and engineering intersection personalization of. This article explains the fundamental mechanism of shape memory and superelasticity, and how they relate to the characteristic performance of self. Design considerations of the novel lumenapposing metal stent nitis spaxus.

Selection of coronary stents journal of the american. This article explains the fundamental mechanism of shape memory and. Material considerations nitinol is an alloy composed of 55 w. Depending on the application, stents are required to have a very high fatigue life ten years of heart beat cycles equals approximately 400. This article explains the fundamental mechanism of shape memory and superelasticity, and how they relate to the characteristic performance of selfexpanding. Vo2, martin meere3, sean mckee1, christopher mccormick4. The wide range of design considerations for balloon catheters can be can be daunting. Vob, martin meerec, sean mckeea, christopher mccormickd a department of mathematics and statistics, university of strathclyde, glasgow g1 1xh, uk bmacsi, department of mathematics and statistics, university of limerick, limerick, ireland. The various design considerations include but are not limited to stress due to tissue interaction, hemodynamic performance, mechanical behavior, and drug delivery in the. In clinical practice, the operator must decide which stent is most appropriate for the patient. The newest generation of drugeluting stents and beyond. Carotid endarterectomy cea has been shown to reduce the incidence of stroke in patients with symptomatic and asymptomatic carotid stenosis.

This range is highly sensitive to heat treatment conditions. An experienced contract manufacturing organization that specializes in the design, development, and manufacturing of balloon catheters can help guide you through the process of bringing your innovative technology to market. Therapy may include specific extralumenal interventions including direct endoscopy. Poncet memry corporation, 4065 campbell avenue menlo park, ca 94025 usa.