nitinol and Vascular-Diseases

to describe the physical properties of shape-memory alloys and the surgical, scientific and commercial applications of nitinol, in particular.. a Medline, Internet and library search with contributions from commerce to describe the alloy's structure, behaviour and biocompatibility, and design for devices constructed from nitinol.. nitinol has the properties of thermal shape memory and superelasticity that make it ideal for many vascular and general surgical prostheses and disposables, and for various commercial applications.. further research into shape-memory alloys from scientific and commercial groups should widen their use in vascular and endovascular surgery.

Topics: Alloys; Biocompatible Materials; Blood Vessel Prosthesis Implantation; Humans; Prosthesis Design; Stents; Vascular Diseases

Early recurrent stenosis of the cephalic arch in autogenous arteriovenous access for hemodialysis is a common problem that requires stenting to prevent thrombosis. Because the results of stenting are unsatisfactory, we compared the efficacy of stent grafts with bare stents in these patients.. All patients who presented with recurrent cephalic arch stenosis >50% within 3 months of successful balloon angioplasty were randomized to have angioplasty and stenting with either a bare nitinol stent or a stent graft. Outcome was assessed by angiography 3 months later. Restenosis was defined as >50% narrowing of the stent lumen or of the vessel margin up to 0.5 cm adjacent to the stent. There were no exclusions.. This report includes data on the outcome of 25 consecutive patients with recurrent cephalic arch stenosis who were treated from April to August 2006. At 3 months, three patients had died and one had undergone a renal transplant. The 21 patients who had angiography at 3 months had patent stents. Restenosis rates were seven of 10 (70%) in the bare stent group and two of 11 (18%) in the stent graft group (P = .024). Life-table analysis at 3 and 6 months showed that primary patency was 82% in the stent graft group and 39% in the bare stent group. One-year primary patency was 32% in the stent graft group and 0% in the bare stent group (P = .0023). During a mean follow-up of 13.7 months, nine patients died, four in the bare stent group and five in the stent graft group. Two patients in the stent graft group had received a renal transplant. The number of interventions per patient-year was 1.9 in the bare stent group and 0.9 in the stent graft group (P = .02).. The use of stent grafts in angioplasty for recurrent cephalic arch stenosis significantly improved short-term restenosis rates and long-term patency compared with the use of bare stents. The significant improvement that emerged during the study caused accrual of patients to be halted for ethical reasons. This study altered our usage of stents for venous stenoses in arteriovenous accesses by eliminating bare nitinol stents in favor of stent grafts.

Topics: Adult; Aged; Aged, 80 and over; Alloys; Angioplasty; Arteriovenous Shunt, Surgical; Blood Vessel Prosthesis; Brachiocephalic Veins; Constriction, Pathologic; Female; Follow-Up Studies; Humans; Kidney Failure, Chronic; Male; Middle Aged; Prospective Studies; Recurrence; Renal Dialysis; Stents; Treatment Outcome; Ultrasonography, Doppler; Vascular Diseases

The StarClose Vascular Closure System is a femoral access site closure technology that uses a flexible nitinol clip to complete a circumferential, extravascular arteriotomy close. The Clip CLosure In Percutaneous Procedures study was initiated to study the safety and efficacy of the StarClose device in subjects undergoing diagnostic and interventional catheterization procedures.. A total of 17 U.S. sites enrolled 596 subjects, with 483 subjects randomized at a 2:1 ratio to receive StarClose or standard compression of the arteriotomy after the percutaneous procedure. The study included roll-in (n = 113), diagnostic (n = 208), and interventional (n = 275) arms with a primary safety endpoint of major vascular complications through 30 days and a primary efficacy endpoint of postprocedure time to hemostasis.. The results of the diagnostic StarClose cohort have been reported separately. Results for the interventional arm revealed major vascular complications occurring in 1.1% of StarClose subjects (2/184) and 1.1% in manual compression subjects (1/91; P = 1.00). No infections were seen in either cohort. Minor complications in the StarClose interventional group occurred at a rate of 4.3% (8/184) and with compression at 9.9% (9/91; P = 0.107). Pseudoaneurysm or arteriovenous fistula was not seen with StarClose. With StarClose, procedural success was 100% (136/136) for the diagnostic group and 98.9% (181/183) in the interventional group. Device success for the treatment group was 86.8%. In the interventional cohort, 87.3% (158/181) of StarClose subjects reported a pain scale of 0-3 compared with 93.3% (84/90) in the compression group, which was not statistically different.. The clinical results of this study demonstrate that the StarClose Vascular Closure System is noninferior to manual compression with respect to the primary safety endpoint of major vascular events in subjects who undergo percutaneous interventional procedures. StarClose significantly reduced time to hemostasis, ambulation, and dischargeability when compared with compression.

Topics: Aged; Alloys; Cardiac Catheterization; Equipment Design; Equipment Safety; Female; Femoral Artery; Follow-Up Studies; Hemostasis; Hemostatic Techniques; Humans; Male; Middle Aged; Postoperative Complications; Prospective Studies; Surgical Instruments; Treatment Outcome; United States; Vascular Diseases

A number of dedicated self expanding nitinol stents have been developed for use in the venous system, with both open cell (OC) and closed cell (CC) designs available. Data comparing these different designs are lacking. The objective of this study was to evaluate outcomes in patients treated with open and closed cells for unilateral chronic iliac vein obstruction.. A single centre retrospective cohort study was conducted, including all patients treated with a dedicated nitinol venous stent between 2014 and 2019. Stent patency and details of re-interventions (including lysis, venoplasty, reinforcement, extension, arteriovenous fistula formation) were examined in the first post-operative year. Subgroup analysis described outcomes for patients treated with OC and CC stents ending above the inguinal ligament and those who required extension into the common femoral vein. Cox regression analysis was used to identify factors associated with loss of primary patency.. A total of 207 patients were included (OC 100 patients, CC 107 patients). There was no significant difference between the groups for age (OC 42 years, CC 44 years); gender (OC and CC 67% female); presence of post-thrombotic lesions (OC 71%, CC 73%); stenting across the inguinal ligament (OC 58%, CC 56%), or presence of inflow disease (OC 49%, CC 47%). Primary and cumulative patency at 12 months were similar between groups (primary: OC 63%, CC 65%; cumulative: OC 93%, CC 90%). Patients with a CC stent across the inguinal ligament had a greater risk of needing multiple re-interventions at one year compared with those with an OC stent (odds ratio 2.84, 95% confidence interval [CI] 1.16 - 6.9) but overall, the only factor significantly associated with loss of primary patency was inflow vessel disease (hazard ratio 3.39, 95% CI 1.73 - 6.62, p < .001).. OC and CC dedicated nitinol venous stents were observed to perform similarly in terms of patency and symptom improvement at one year. Disease of the inflow vessels was the most important factor associated with a loss of stent patency irrespective of stent design.

Topics: Adult; Alloys; Female; Humans; Iliac Vein; Lasers; Male; Retrospective Studies; Stents; Treatment Outcome; Vascular Diseases; Vascular Patency

To assess the midterm patency and long-term safety of placement of a dedicated venous stent (Vici Venous Stent System) for the treatment of venous lesions of the iliofemoral outflow tract.. Patients with unilateral obstructive disease of the iliofemoral veins and a Clinical, Etiological, Anatomical, Pathophysiological class of 3 or higher or a Venous Clinical Severity Score of 2 or greater were enrolled in this prospective, multicenter, single-arm study at 23 sites in the United States and Europe. The patients were followed up for 36 months after the index procedure for the assessment of patency and up to 60 months for the assessment of safety. The clinical outcomes in 11 patients with a stent fracture were assessed.. A total of 200 patients enrolled in 2 cohorts (ie, feasibility cohort, n = 30; pivotal cohort, n = 170) were combined for this analysis. The overall 36-month primary patency rate was 71.7% (86/120), and the 36-month primary patency rate was 96.4% (27/28) for the nonthrombotic group and 64.1% (59/92) for the postthrombotic group. The freedom from major adverse events was 81.2% (53/65) through 60 months. The 60-month Kaplan-Meier estimate of freedom from target vessel revascularization (TVR) was 84.3%. In 9 of the 11 patients who had a stent fracture (1 patient with nonthrombotic etiology and 10 patients with postthrombotic etiology) identified at 12 months, the stents extended into the common femoral vein. The TVR rates and clinical outcomes were similar between patients with and without a stent fracture.. The results of the VIRTUS study demonstrated good midterm patency and long-term safety following the placement of a dedicated venous stent for iliofemoral obstruction.

Topics: Endovascular Procedures; Humans; Iliac Vein; Prospective Studies; Retrospective Studies; Stents; Time Factors; Treatment Outcome; Vascular Diseases; Vascular Patency

To compare the double mesh nitinol stent (DNS) versus the self-expanding stent-graft (SES) in recurrent/resistant cephalic vein arch stenosis in dialysis fistulae.. 17 cases with recurrent/resistant stenosis of the cephalic vein arch treated with a DNS were compared retrospectively with 18 cases treated with an SES. Stenting was performed either for significant recoil post-angioplasty with high-pressure balloons or in recurrent stenoses. Patients were followed up with Doppler ultrasound in our vascular access surveillance programme. Primary and assisted primary patency rates at 3, 6 and 12 months were estimated by Kaplan-Meier analysis.. Both stents showed 100% technical success immediately post-stenting, defined as residual stenosis < 30%. 3, 6 and 12 month primary patency of the DNS was 82.4%, 69.7% and 28.1% versus 88.9%, 77.8% and 72.2% for the SES. The DNS had a mean primary patency of 242.4 days compared to 896.3 days for the SES (p = 0.021). 12 month assisted primary patency was 88.2% (DNS) and 100% (SES). The DNS had a mean assisted primary patency of 812 days compared to 1390.3 days for the SES, though this did not reach statistical significance. No stent fractures were identified at 2 years in either group.. Both stents had 100% technical success with no stent fractures. SES showed statistically significant higher primary patency. Assisted primary patency was also higher, though this did not reach statistical significance.

Topics: Aged; Alloys; Arteriovenous Shunt, Surgical; Brachiocephalic Veins; Constriction, Pathologic; Equipment Design; Female; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Recurrence; Renal Dialysis; Retrospective Studies; Stents; Surgical Mesh; Treatment Outcome; Ultrasonography, Doppler; Vascular Diseases

Topics: Alloys; Angioplasty, Balloon; Constriction, Pathologic; Graft Occlusion, Vascular; Humans; Iliac Vein; Liver Transplantation; Male; Mesenteric Veins; Portal Vein; Prosthesis Design; Self Expandable Metallic Stents; Treatment Failure; Vascular Diseases; Vascular Grafting; Vascular Patency; Young Adult

To report safety and efficacy of a skip stent technique using nitinol stents in patients with chronic bilateral iliocaval venous occlusions.. A retrospective analysis of 48 consecutive patients (32 men; mean age, 40.7 years; age range, 18-68 years) with chronic bilateral iliocaval obstructions treated using a nonoverlapping stent technique was conducted at a single center. None of the patients had May-Thurner syndrome. Iliocaval confluence was treated by deploying a nitinol stent in inferior vena cava (IVC) and a nitinol stent in each common iliac vein close to the caval stent. Patency of stents was assessed by duplex US at 2 weeks, 3 months, and 6 months and yearly thereafter.. Recanalization and stent reconstruction was technically successful in 47 (98%) patients. The sinus-XL venous stent was used to treat IVC (95 [100%]). Common iliac and external iliac veins were treated with sinus-Venous and VENOVO stents (80 [83%] and 16 [17%] limbs, respectively). External iliac and common femoral veins were treated with sinus-Venous and VENOVO stents (83 [92%] and 7 [18%] limbs, respectively). Early thrombosis (< 30 days) of the iliac vein with stent occurred in 2 limbs. Cumulative primary, assisted primary, and secondary patency rates at 30 months were 74%, 83%, and 97%.. Findings of this study suggest that leaving a skipped lesion at the level of iliocaval confluence may not adversely affect stent patency. Patency rates were comparable with other reported techniques of stent reconstruction at the level of iliocaval confluence.

Topics: Adolescent; Adult; Aged; Alloys; Chronic Disease; Constriction, Pathologic; Endovascular Procedures; Female; Humans; Iliac Vein; Male; Middle Aged; Retrospective Studies; Self Expandable Metallic Stents; Time Factors; Treatment Outcome; Vascular Diseases; Vascular Patency; Vena Cava, Inferior; Young Adult

Endovascular treatment is indicated for the treatment of symptomatic thoracic central vein obstruction (TCVO) but is limited by high rates of restenosis and the need for re-intervention. The aim was to assess the safety and mid-term patency of a novel dedicated venous stent for the treatment of TCVO of benign aetiology.. This was a prospective single centre observational study of 20 patients (median age 65 years, 50% male) referred for the treatment of symptomatic chronic (>three months duration) TCVO between May 2016 and January 2018. Balloon angioplasty with implantation of a self expanding nitinol stent (Vici, Boston Scientific, Marlborough, MA, USA) was performed in all patients. Clinical records including demographics, aetiologies and types of TCVO, and procedural details were recorded. Patients were followed up clinically at one, six, and 12 months. Primary and assisted primary patency were reported.. All 20 lesions were total occlusions, of which 55% (n = 11) were de novo, 10% (n = 2) peri-stent restenosis, and 35% (n = 7) in-stent re-occlusion. The aetiology of TCVO was predominantly (95%) because of multiple or prolonged central venous line insertion. The procedural success rate was 90% (18/20) with no procedural complications. The median follow up was 13.5 months. Primary patency was 100% at 6 months. One patient required re-intervention for stent in segment restenosis at 7 months. The assisted primary patency rate was 100% at 12 months.. Endovascular treatment of benign TCVO with the novel dedicated venous stent was safe and effective in relieving obstructive symptoms with excellent one year patency rates.

Topics: Aged; Alloys; Chronic Disease; Constriction, Pathologic; Endovascular Procedures; Female; Humans; Male; Middle Aged; Phlebography; Prospective Studies; Registries; Risk Factors; Self Expandable Metallic Stents; Thorax; Time Factors; Treatment Outcome; Vascular Diseases; Vascular Patency; Veins

The Amplatzer vascular plugs (AVPs), including AVP 4, have excellent occlusion; however, insufficient embolization or recanalization may occasionally occur. This study aimed to evaluate the feasibility and effectiveness of internal coil packing method to insert microcoils into the AVP 4 using an experimental vascular model. The insertion of a 1.7 F microcatheter through the nitinol mesh of the AVP 4 was not possible. Only 0.010-inch electrolytic detachable microcoils could be inserted through catheter tips in contact with nitinol mesh. The internal coil packing of the AVP 4 may be accomplished by inserting 0.010-inch microcoils into the AVP 4 in cases of continued perfusion or recanalization with required short-segment embolization.

Topics: Alloys; Prosthesis Design; Septal Occluder Device; Vascular Diseases

Since the introduction of various endovascular graft materials such as expanded polytetrafluoroethylene (e-PTFE) and Dacron

Topics: Alloys; Animals; Blood Vessel Prosthesis; Cattle; Cell Line; Endothelial Cells; Materials Testing; Membranes, Artificial; Models, Cardiovascular; Myocytes, Smooth Muscle; Silk; Vascular Diseases

The article is dedicated to outstanding Soviet and Russian interventional radiologist, Professor I. Kh. Rabkin and his priorities in the development of roentgenoendovascular methods of diagnosis and treatment of arterial and venous diseases. Virtually simultaneously with American surgeons, I. Kh. Rabkin not only worked out anew method of intravascular stenting of arteries with spirals made of shape-memory metal ( nitinol) but was the first in the world who in 1984 successfully stented the external iliac artery in a 56-year-old male patient with stage IV limb ischaemia.

Topics: Alloys; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; History, 20th Century; Humans; Inventions; Professional Practice; Radiography, Interventional; Russia; Stents; Vascular Diseases

The purpose of this prospective registry was to evaluate the safety and efficacy, at 1 year, of the use of drug-eluting balloons (DEB) for the treatment of superficial femoral artery (SFA) in-stent restenosis (ISR).. The use of the self-expanding nitinol stent has improved the patency rate of SFA after percutaneous transluminal angioplasty (PTA). As the population with SFA stenting continues to increase, occurrence of ISR has become a serious problem. The use of DEB has showed promising results in reducing restenosis recurrence in coronary stents.. From December 2009 to December 2010, 39 consecutive patients underwent PTA of SFA-ISR in our institution. All patients underwent conventional SFA PTA and final post-dilation with paclitaxel-eluting balloons (IN.PACT, Medtronic, Minneapolis, Minnesota). Patients were evaluated up to 12 months.. Technical and procedural success was achieved in every patient. No in-hospital major adverse cardiac and cerebrovascular events occurred. At 1 year, 1 patient died due to heart failure. Primary endpoint, primary patency rate at 12 months, was obtained in 92.1% (35 patients). At 1 year, patients were asymptomatic for claudication, and duplex assessment demonstrated lack of recurrent restenosis (100% rate of Secondary patency). The presence of an occlusive restenosis at the time of treatment was not associated with an increased restenosis rate, when compared with non-occlusive restenosis, at 1 year.. The data suggest that adjunctive use of DEB for the treatment of SFA-ISR represents a potentially safe and effective therapeutic strategy. These data should be considered hypothesis-generating to design a randomized trial.

Topics: Aged; Alloys; Angioplasty; Coronary Restenosis; Drug-Eluting Stents; Female; Femoral Artery; Humans; Male; Middle Aged; Prospective Studies; Registries; Stents; Treatment Outcome; Vascular Diseases; Vascular Patency

Topics: Adult; Aged; Aged, 80 and over; Alloys; Angioplasty; Arteriovenous Shunt, Surgical; Blood Vessel Prosthesis; Brachiocephalic Veins; Constriction, Pathologic; Female; Graft Occlusion, Vascular; Humans; Kidney Failure, Chronic; Male; Middle Aged; Recurrence; Renal Dialysis; Stents; Treatment Outcome; Ultrasonography, Doppler; Vascular Diseases; Vascular Patency

Nitinol, a nickel-titanium alloy, is a valuable material in the construction of interventional endoluminal devices because of its biocompatibility, super elasticity, high resiliency and shape memory. The possibility of nickel toxicity has been raised with devices constructed of Nitinol. Our investigation examines the long-term corrosive behavior of this alloy in experimental and biological environments.. We performed three levels of study. Microscopic examination was made of 64 devices of various sizes, randomly selected from 240 Amplatzer Septal Occluders that had been exposed to saline solution at 37 degrees C for fourteen months. All samples were studied by electron microscopy ranging from 50 to 5000 times magnification. We also studied microscopically 3 Amplatzer devices explanted 18-36 months after implantation in dogs, and 2 Amplatzer Septal Occluders removed from patients 18 months (cardiac transplant) and 19 months (died of causes unrelated to device placement) after implantation, which were examined grossly and by electron microscopy up to 5000 times magnification. We then measured the levels of nickel in the blood using inductive plasma mass spectroscopy in 19 patients with implanted Amplatzer devices, making measurements before and 6 months after implantation.. Electron microscopy showed an intact titanium oxide layer with no evidence of corrosion in vitro and in vivo. One explanted device in direct contact with the platinum leads of a pacemaker for eighteen months showed minor pitting of the titanium oxide layer believed to be galvanic in nature. No wire fractures were found in vitro after cycle testing with 400 million cycles, nor in devices taken from the animals and humans. Biochemical studies showed no significant elevation of levels of nickel levels after implantation.. Nitinol wire of Amplatzer septal occlusion devices is resistant to corrosion when exposed to physiologic saline solution, and in experimental animals as well as humans. A device in contact with a platinum pacemaker electrode developed minimal pitting of the titanium oxide layer, believed to be galvanic in nature and of no structural or clinical significance. There is no increase of concentrations of nickel in the blood of patients who have received Amplatzer nitinol devices. These favorable testing results reveal that nickel-titanium is an inert, corrosion resistant alloy.

Topics: Adolescent; Adult; Alloys; Animals; Balloon Occlusion; Child; Child, Preschool; Corrosion; Disease Models, Animal; Dogs; Equipment Failure; Humans; Male; Models, Biological; Postoperative Complications; Time Factors; Vascular Diseases