An Apparatus to Measure the Shape Memory Properties of Nitinol Tubes for Medical Applications

Chen, J.T.; Duerig, T.W.; Pelton, Alan R.; Stöckel, D.

doi:10.1051/jp4/1995581247

Cited by 7 publications

(7 citation statements)

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“…Most self-expanding stents are now made of nitinol which is an alloy of nickel and titanium. An important feature of nitinol that is beneficial in the self-expanding design of stents is its thermal shape memory and super-elasticity [10, 36, 42–44]. On the contrary, stiffer balloon-expandable stents have less radial strength and high chances of deformation and fracture [45].…”

Section: Discussionmentioning

confidence: 99%

Systematic Review and Proportional Meta-Analysis of Endarterectomy and Endovascular Therapy with Routine or Selective Stenting for Common Femoral Artery Atherosclerotic Disease

Changal

Syed

Dar

et al. 2019

Journal of Interventional Cardiology

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Introduction. Common femoral endarterectomy (CFE) has been the therapy of choice for common femoral artery atherosclerotic disease (CFA-ASD). In the past, there was inhibition to treat CFA-ASD endovascularly with stents due to fear of stent fracture and compromise of future vascular access site. However, recent advances and new evidence suggest that CFA may no longer be a ‘stent-forbidden zone’. In the light of new evidence, we conducted a meta-analysis to determine the use of endovascular treatment for CFA-ASD and compare it with common femoral endarterectomy in the present era. Methods. Using certain MeSH terms we searched multiple databases for studies done on endovascular and surgical treatment of CFA-ASD in the last two decades. Inclusion criteria were randomized control trials, observational, prospective, or retrospective studies evaluating an endovascular treatment or CFE for CFA-ASD. For comparison, studies were grouped based on the treatment strategy used for CFA-ASD: endovascular treatment with selective stenting (EVT-SS), endovascular treatment with routine stenting (EVT-RS), or common femoral endarterectomy (CFE). Primary patency (PP), target lesion revascularization (TLR), and complications were the outcomes studied. We did proportional meta-analysis using a random-effect model due to heterogeneity among the included studies. If confidence intervals of two results do not overlap, then statistical significance is determined. Results. Twenty-eight studies met inclusion criteria (7 for EVT-RS, 8 for EVT-SS, and 13 for CFE). Total limbs involved were 2914 (306 in EVT-RS, 678 in EVT-SS, and 1930 in CFE). The pooled PP at 1 year was 84% (95% CI 75-92%) for EVT-RS, 78% (95% CI 69-85%) for EVT-SS, and 93% (95% CI 90-96%) for CFE. PP at maximum follow-up in EVT-RS was 83.7% (95% CI 74-91%) and in CFE group was 88.3% (95% CI 81-94%). The pooled target lesion revascularization (TLR) rate at one year was 8% (95% CI 4-13%) for EVT-RS, 19% (95% CI 14-23%) for EVT-SS, and 4.5% (95% CI 1-9%) for CFE. The pooled rate of local complications for EVT-RS was 5% (95% CI 2-10%), for EVT-SS was 7% (95% CI 3 to 12%), and CFE was 22% (95% CI 14-32%). Mortality at maximum follow-up in CFE group was 23.1% (95% CI 14-33%) and EVT-RS was 5.3% (95% CI 1-11%). Conclusion. EVT-RS has comparable one-year PP and TLR as CFE. CFE showed an advantage over EVT-SS for one-year PP. The complication rate is lower in EVT RS and EVT SS compared to CFE. At maximum follow-up, CFE and EVT-RS have similar PP but CFE has a higher mortality. These findings support EVT-RS as a management alternative for CFA-ASD.

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Section: Discussionmentioning

confidence: 99%

Systematic Review and Proportional Meta-Analysis of Endarterectomy and Endovascular Therapy with Routine or Selective Stenting for Common Femoral Artery Atherosclerotic Disease

Changal

Syed

Dar

et al. 2019

Journal of Interventional Cardiology

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“…However, studies that compare BFR and DSC show very similar results as long as the strain is no greater than 2.5%; 16 17 reported As values obtained using the BFR method, but stated that As could not be determined with DSC testing due to the presence of a rhombohedral phase (R phase) on the thermograms. Norwich did not provide transformation temperature values, but stated that the results "from each method agreed within one degree", while the other two studies' reported Af temperatures showed differences ranging from 4 to 6 °C between the test methods.…”

Section: Discussionmentioning

confidence: 99%

Comparison of the transformation temperatures of heat-activated Nickel-Titanium orthodontic archwires by two different techniques

et al. 2016

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Objectives: The purpose of this study was to investigate the suitability of the Bend and Free Recovery (BFR) method as a standard test method to determine the transformation temperatures of heat-activated Ni-Ti orthodontic archwires. This was done by determining the transformation temperatures of two brands of heat-activated Ni-Ti orthodontic archwires using the both the BFR method and the standard method of Differential Scanning Calorimetry (DSC). The values obtained from the two methods were compared with each other and to the manufacturer-listed values. Methods: Forty heat-activated Ni-Ti archwires from both Rocky Mountain Orthodontics (RMO) and Opal Orthodontics (Opal) were tested using BFR and DSC. Round (0.016 inches) and rectangular (0.019 × 0.025 inches) archwires from each manufacturer were tested. The austenite start temperatures (As) and austenite finish temperatures (Af) were recorded. Results: For four of the eight test groups, the BFR method resulted in lower standard deviations than the DSC method, and, overall, the average standard deviation for BFR testing was slightly lower than for DSC testing. Statistically significant differences were seen between the transformation temperatures obtained from the BFR and DSC test methods. However, the Af temperatures obtained from the two methods were remarkably similar with the mean differences ranging from 0.0 to 2.1 °C: Af Opal round (BFR 26.7 °C, DSC 27.6 °C) and rectangular (BFR 27.6 °C, DSC 28.6 °C); Af RMO round (BFR 25.5 °C, DSC 25.5 °C) and rectangular (BFR 28.0 °C, DSC 25.9 °C). Significant differences were observed between the manufacturer-listed transformation temperatures and those obtained with BFR and DSC testing for both manufacturers. Significance: The results of this study suggest that the Bend and Free Recovery method is suitable as a standard method to evaluate the transformation temperatures of heat-activated Ni-Ti orthodontic archwires.

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“…In addition, they are characterized by a pronounced stress hysteresis during loading and deflection. Thus, nitinol stents ret urn to their original shape when the external stress declines (9,10). This an ows for a biased stiffness, meaning that nitinol stents have s ma ll chronic outward forces.…”

Section: • Weightmentioning

confidence: 99%

Physical Properties of Endovascular Stents: An Experimental Comparison

Duda

Wiskirchen

Tepe

et al. 2000

Journal of Vascular and Interventional Radiology

189

116

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An Apparatus to Measure the Shape Memory Properties of Nitinol Tubes for Medical Applications

Cited by 7 publications

References 0 publications

Systematic Review and Proportional Meta-Analysis of Endarterectomy and Endovascular Therapy with Routine or Selective Stenting for Common Femoral Artery Atherosclerotic Disease

Systematic Review and Proportional Meta-Analysis of Endarterectomy and Endovascular Therapy with Routine or Selective Stenting for Common Femoral Artery Atherosclerotic Disease

Comparison of the transformation temperatures of heat-activated Nickel-Titanium orthodontic archwires by two different techniques

Physical Properties of Endovascular Stents: An Experimental Comparison

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