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This complaint was found during a recent clinical evaluation review/literature search of this device.The citation is as follows: hada, y., fujii, h., shimizu, m., yamawake, n., & nishizaki, m.(2017).Effectiveness of bare metal stent implantation for the treatment of coronary artery aneurysm: a multimodality imaging evaluation.Internal medicine.Doi:10.2169/internalmedicine.8532-16.Complaint conclusion: as reported in the literature publication by hada et al effectiveness of bare metal stent implantation for the treatment of coronary artery aneurysm: a multimodality imaging evaluation, intern med.(b)(6) 2017, in (b)(6) 2007, a (b)(6) man was admitted with effort angina.The patients¿ coronary risk factors were hypertension, dyslipidemia, obesity and smoking.The patient had undergone bare metal stent (bms) implantation (bx velocity: 3.5 in diameter, 28 mm in length) for proximal left anterior descending artery (lad) 2 years previously.Coronary angiography (cag) revealed severe stenosis of the mid lad.Intravascular ultrasound (ivus) revealed severe negative remodeling at the culprit lesion of the mid lad.The patient underwent ses implantation (cypher: 3.5 mm in diameter, 23 mm in length) for the mid lad.Ivus after ses implantation revealed well-expanded stent struts without incomplete stent apposition.Follow-up cag was performed 9 months after ses implantation.Peri-stent contrast staining (pss) was observed in the ses.Control of hypertension was poor; therefore, the patients¿ blood pressure was reduced more strictly.Cag performed at 46 months after ses implantation showed contrast staining outside the stent struts was more marked and met the classic definition of caa.Ivus and optical coherence tomography (oct) revealed incomplete stent apposition and stent fracture at the caa.However, in the bms, an oct examination revealed complete stent apposition.Non-obstructive coronary angioscopy (cas) revealed the fractured edge of the ses at the caa.The fracture had occurred in a joint of the ses.The stent strut was fully visible and not covered by neointima (grade 0 neointimal coverage).In contrast, complete neointimal coverage was observed in the bms site and proximal edge of the ses site (grade 2 neointimal coverage).No thrombus was detected in the ses.When we performed cag at 81 months after ses implantation, the caa had expanded to more than twice the size of the reference vessel diameter.The patient therefore underwent bms implantation (3.5 mm in diameter, 26 mm in length) to cover the caa.Fortunately, the flow of the large diagonal branch was maintained after stenting.Follow-up cag was performed at 91 months after ses implantation (10 months after the use of bms to treat caa).Regression of the aneurysm was observed.Oct revealed vessel wall dilatation and malapposed stent struts.However, the size of the caa had diminished, and a very thin layer of endothelium was visible on the struts.The patient continued taking 100 mg/day of aspirin and 75 mg/day of clopidogrel.The patient was free from cardiac events throughout the follow-up period.The product was not returned for analysis.No lot number was provided therefore a product history record (phr) review could not be generated.The reported ¿stent under-expanded¿ and ¿stent fractured - in patient¿ could not be confirmed as the devices were not returned for analysis.The exact cause could not be determined.The likely cause of the peri-stent staining is the incomplete apposition of the cypher stent when implanted.According to a review article ¿stents are more likely to fracture in the presence of the following factors: balloon or stent overexpansion, as it may theoretically weaken the stent struts; stent overlap, which results in localized rigidity creating hinge points that deform the stent leading to fracture; stent length: longer stents may be subjected to higher radial forces; inappropriate handling of stent; stenting technique: an example of stenting technique that might cause stent fracture is crush technique.A case has been reported of stent strut fracture in a bifurcation lesion treated with crush stenting, resulting in restenosis.Anatomic and pathologic factors which include the following: tortuous and highly angulated vessel; long lesions; change in vessel angulation after stent implantation, which can create a significant distortion force; complex lesions, as it was more frequent in the complex lesion subset of chronic total occlusion; stent location, as it is more common in right coronary artery (rca) and saphenous graft locations as these vessels are dynamic during cardiac contractions.Stents in these locations may be subjected to repetitive distorting forces, as some segments of these vessels have more flexion points during the cardiac cycle.Repetitive cardiac contraction exposes the stent to compression, torsion, kinking, elongation, bending, and shear stress, which can cause fracture from mechanical fatigue.The points of stent fractures are usually located at hinges subjected to either medial or shear forces created by non-uniform vessel anatomy.According to the instructions for use, although this not a risk mitigation ¿before opening, carefully inspect the stent delivery system package, and check for damage to the sterile barrier.Prior to using the device, carefully remove the system from the package and inspect it for bends, kinks, and other damage.Do not use the device if any damage to the packaging is noted.Under fluoroscopic visualization, inflate the balloon to at least the nominal pressure to deploy the stent, but do not exceed the labeled rated burst pressure of 16 atm (1621 kpa).Optimal expansion requires the stent to be in full contact with the artery wall, with the stent internal diameter matching the size of the reference vessel diameter.Stent wall contact should be verified through routine angiography or intravascular ultrasound.Fully cover the entire lesion and balloon treated area (including dissections) with the cypher stent, allowing for adequate stent coverage into healthy tissue proximal and distal to the lesion.Confirm that the stent is adequately expanded by angiographic injection through the guiding catheter.All efforts should be taken to assure that the stent is not under-dilated.If the deployed stent size is still inadequate with respect to vessel diameter, or if full contact with the vessel wall is not achieved, a larger balloon may be used to expand the stent further.The stent may be further expanded using a low profile, high pressure, and non-compliant balloon catheter.If this is required, the stented segment should be recrossed carefully with a prolapsed guidewire to avoid dislodging the stent.The balloon should be centered within the stent and should not extend outside of the stented region.¿ the reported ¿in-stent coronary artery restenosis¿ and the reported ¿effort angina¿ could not be confirmed as the devices were not returned for analysis.The exact cause could not be determined.Angina pectoris and/or chest pain are symptoms of cardiac ischemia generally related to a coronary artery vessel obstruction and/or vasospasm.Subsequently here is a potential link between the reported ¿in-stent coronary artery restenosis¿ and the reported ¿effort angina¿.As no lot number, catalogue code or other product information was supplied a phr could not be completed.The information available does not suggest a design or manufacturing related cause for the reported event; therefore, no corrective/preventive action will be taken at this time.
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As reported in the literature publication by hada et al effectiveness of bare metal stent implantation for the treatment of coronary artery aneurysm: a multimodality imaging evaluation, intern med.(b)(6) 2017, in (b)(6) 2007, a (b)(6) man was admitted with effort angina.The patients¿ coronary risk factors were hypertension, dyslipidemia, obesity and smoking.The patient had undergone bare metal stent (bms) implantation (bx velocity: 3.5 in diameter, 28 mm in length) for proximal left anterior descending artery (lad) 2 years previously.Coronary angiography (cag) revealed severe stenosis of the mid lad (fig.1a).Intravascular ultrasound (ivus) revealed severe negative remodeling at the culprit lesion of the mid lad.The patient underwent ses implantation (cypher: 3.5 mm in diameter, 23 mm in length) for the mid lad (fig.1b).Ivus after ses implantation revealed well-expanded stent struts without incomplete stent apposition.Follow-up cag was performed 9 months after ses implantation.Peri-stent contrast staining (pss) was observed in the ses (fig.1c).Control of hypertension was poor; therefore, the patients¿ blood pressure was reduced more strictly.Cag performed at 46 months after ses implantation showed contrast staining outside the stent struts was more marked and met the classic definition of caa (fig.1d).Ivus and optical coherence tomography (oct) revealed incomplete stent apposition (fig.2a, c) and stent fracture at the caa (fig.2b, d).However, in the bms, an oct examination revealed complete stent apposition (fig.2e).Non-obstructive coronary angioscopy (cas) revealed the fractured edge of the ses at the caa (fig.3a, b).The fracture had occurred in a joint of the ses.The stent strut was fully visible and not covered by neointima (grade 0 neointimal coverage).In contrast, complete neointimal coverage was observed in the bms site and proximal edge of the ses site (grade 2 neointimal coverage) (fig.3a, b and c).No thrombus was detected in the ses.When we performed cag at 81 months after ses implantation, the caa had expanded to more than twice the size of the reference vessel diameter (fig.4a).The patient therefore underwent bms implantation (3.5 mm in diameter, 26 mm in length) to cover the caa.Fortunately, the flow of the large diagonal branch was maintained after stenting.Follow-up cag was performed at 91 months after ses implantation (10 months after the use of bms to treat caa).Regression of the aneurysm was observed (fig.4b).Oct revealed vessel wall dilatation and malapposed stent struts (fig.5a, c).However, the size of the caa had diminished, and a very thin layer of endothelium was visible on the struts (fig.5b, c).The patient continued taking 100 mg/day of aspirin and 75 mg/day of clopidogrel.The patient was free from cardiac events throughout the follow-up period.
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