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Process of prototyping coronary stents from biodegradable Fe-Mn alloys

Hermawan H, Mantovani D

Acta Biomater, 2013 Nov;9(10):8585-92.
PMID: 23665503 DOI: 10.1016/j.actbio.2013.04.027

Biodegradable stents are considered to be a recent innovation, and their feasibility and applicability have been proven in recent years. Research in this area has focused on materials development and biological studies, rather than on how to transform the developed biodegradable materials into the stent itself. Currently available stent technology, the laser cutting-based process, might be adapted to fabricate biodegradable stents. In this work, the fabrication, characterization and testing of biodegradable Fe-Mn stents are described. A standard process for fabricating and testing stainless steel 316L stents was referred to. The influence of process parameters on the physical, metallurgical and mechanical properties of the stents, and the quality of the produced stents, were investigated. It was found that some steps of the standard process such as laser cutting can be directly applied, but changes to parameters are needed for annealing, and alternatives are needed to replace electropolishing.

Matched MeSH terms: Stents*
Fulltext eComment: Trans-pericardial extra-anatomic aortic bypass for coarctation of the aorta

Sachithanandan A, Badmanaban B

Interact Cardiovasc Thorac Surg, 2011 Jul;13(1):100.
PMID: 21697404 DOI: 10.1510/icvts.2010.265264A
Matched MeSH terms: Stents*
Fulltext Subclavian artery stent fracture

Lee CE, Shaiful AY, Hanif H

Med J Malaysia, 2009 Dec;64(4):330-2.
PMID: 20954563 MyJurnal

We report a case of a 52 year-old dentist who had stent implantation for a left subclavian artery stenosis. However, this was later complicated by a stent fracture within one week of stent placement. A chest radiograph showed two pieces of the fractured stent, which was confirmed by computed tomographic angiogram (CTA) of the affected artery. We then discuss the occurrence of stent fractures, which are not uncommon but serious complications of endovascular therapy.

Matched MeSH terms: Stents/adverse effects*
Computed tomography scan for cardiac interventions

Sim KH, Ong TK, Chin SP, Wong M

Indian Heart J, 2007 Mar-Apr;59(2 Suppl B):B25-32.
PMID: 19153433
Matched MeSH terms: Stents*
Fulltext Tracheobronchial stenting is safe and effective in relieving upper airway obstruction

Pang YK, Liam CK, Leow CH, Shyamala P, Zal AR

Med J Malaysia, 2006 Jun;61(2):147-50.
PMID: 16898303 MyJurnal

Many studies have shown that tracheobronchial stenting is effective in relieving respiratory distress secondary to major airway obstruction due to lung or oesophageal cancer. A retrospective review on the benefits and complications of self-expandable metallic stent (SEMS) insertion through flexible bronchoscopy for the palliative treatment of upper airway obstruction in University Malaya Medical Centre was performed. Ten patients underwent this procedure. Relief of dyspnoea was immediate following stent insertion in all patients. Stent migration occurred in one patient and three patients had restenosis of the central airway. We conclude that tracheobronchial stenting via flexible bronchoscopy is feasible and safe.

Matched MeSH terms: Stents*
Fulltext Tracheal stent in the treatment of tracheal stenosis

Dipak S, Prepageran N, Rahmat O, Raman R

Med J Malaysia, 2005 Oct;60(4):498-501.
PMID: 16570716

The use of airway stents for the treatment of benign airway stenosis is increasingly advocated. However, the long-term safety and efficiency of these devices has not been established. We present a case of tracheal stenosis. which persisted despite open surgical and laser correction. The patient required tracheal stent insertion and is currently well with no respiratory difficulty. The use of metallic or silicon intraluminal stent remains appropriate in cases in which there is defined and relative short-term end point of treatment.

Matched MeSH terms: Stents*
Clinical experience in coronary stenting with the Vivant Z Stent

Chee KH, Siaw FS, Chan CG, Chong WP, Imran ZA, Haizal HK, et al.

Int J Clin Pract, 2005 Jun;59(6):628-31.
PMID: 15924588

This single centre study was designed to demonstrate feasibility, safety and efficacy of the Vivant Z stent (PFM AG, Cologne, Germany). Patients with de novo lesion were recruited. Coronary angioplasty was performed with either direct stenting or after balloon predilatation. Repeated angiogram was performed 6 months later or earlier if clinically indicated. Between January to June 2003, a total of 50 patients were recruited (mean age 55.8 +/- 9 years). A total of 52 lesions were stented successfully. Mean reference diameter was 2.77 mm (+/-0.59 SD, range 2.05-4.39 mm) with mean target lesion stenosis of 65.5% (+/-11.6 SD, range 50.1-93.3%). Forty-six lesions (88.5%) were American College of Cardiologist/American Heart Association class B/C types. Direct stenting was performed in 18 (34.6%) lesions. Mean stent diameter was 3.18 mm (+/-0.41 SD, range 2.5-4 mm), and mean stent length was 14.86 mm (+/-2.72 SD, range 9-18 mm). The procedure was complicated in only one case which involved the loss of side branch with no clinical sequelae. All treated lesions achieved Thrombolysis In Myocardial Infarction 3 flow. Mean residual diameter stenosis was 12.2% (+/-7.55 SD, range 0-22.6%) with acute gain of 1.72 mm (+/-0.50 SD, range 0.5-2.8). At 6 months, there was no major adverse cardiovascular event. Repeated angiography after 6 months showed a restenosis rate of 17% (defined as >50% diameter restenosis). Mean late loss was 0.96 mm (+/-0.48 SD) with loss index of 0.61 (+/-0.38 SD). The restenosis rate of those lesions less than 3.0 mm in diameter was 22.2% compared with 6.25% in those lesions more than 3.0 mm in diameter. The Vivant Z stent was shown to be safe and efficacious with low restenosis rate in de novo coronary artery lesion.

Matched MeSH terms: Stents*
Risk factors for augmentation of the flow of blood to the lungs in pulmonary atresia with intact ventricular septum after radiofrequency valvotomy

Alwi M, Kandavello G, Choo KK, Aziz BA, Samion H, Latiff HA

Cardiol Young, 2005 Apr;15(2):141-7.
PMID: 15845156

Some patients with pulmonary atresia with an intact ventricular septum, mild to moderate right ventricular hypoplasia, and a patent infundibulum remain duct dependent on the flow of blood through the arterial duct despite adequate relief of the obstruction within the right ventricular outflow tract. The objective of our study was to review the risk factors for stenting of the patent arterial duct, or construction of a Blalock-Taussig shunt, in the patients with pulmonary atresia and an intact ventricular septum who remain duct-dependent following radiofrequency valvotomy and dilation of the imperforate pulmonary valve. We reviewed the data from 53 patients seen between November 1995 and December 2001. Of the 47 patients who survived, 6 required stenting of the patent arterial duct, while 4 needed construction of a modified Blalock-Taussig shunt to augment the flow of blood to the lungs at a mean of 7 plus or minus 5.7 days following the initial intervention. The remaining 37 patients required no additional procedures. We compared the findings in these two groups. The mean diameter of the tricuspid valve in the patients requiring early reintervention was 8.5 plus or minus 3.7 millimetres, giving a Z-score of -1.1 plus or minus 1.47, whilst those in the group without early reintervention had values of 10.7 plus or minus 2.2 millimetres, giving a Z-score of -0.58 plus or minus 1.18 (p equal to 0.003). No statistically significant differences were found in right ventricular morphology, McGoon ratio, or residual obstruction across the right ventricular outflow tract after decompression of the right ventricle. The diameter of the tricuspid valve, therefore, appears to be the only factor predicting the need for augmentation of flow of blood to the lungs. As just over one-fifth of our survivors required such augmentation, we hypothesize that stenting of the patent arterial duct may be performed as an integral part of primary transcatheter therapy in patients with pulmonary atresia and intact ventricular septum who have moderate right ventricular hypoplasia and a small tricuspid valve.

Matched MeSH terms: Stents*
Modified Activation Technique for Nasal Stent of Nasoalveolar Molding Appliance for Columellar Lengthening in Bilateral Cleft Lip/Palate

Patil PG, Nimbalkar-Patil SP

J Prosthodont, 2018 Jan;27(1):94-97.
PMID: 27002917 DOI: 10.1111/jopr.12464

Bilateral cleft lip/cleft palate is associated with nasal deformities typified by a short columella. The presurgical nasoalveolar molding (NAM) therapy approach includes reduction of the size of the intraoral alveolar cleft as well as positioning of the surrounding deformed soft tissues and cartilages. In a bilateral cleft patient, NAM, along with columellar elongation, eliminates the need for columellar lengthening surgery. Thus the frequent surgical intervention to achieve the desired esthetic results can be avoided. This article proposes a modified activation technique of the nasal stent for a NAM appliance for columellar lengthening in bilateral cleft lip/palate patients. The design highlights relining of the columellar portion of the nasal stent and the wire-bending of the nasal stent to achieve desirable results within the limited span of plasticity of the nasal cartilages. With this technique the vertical taping of the premaxilla to the oral plate can be avoided.

Matched MeSH terms: Stents*
Fulltext Endovascular stent graft repair of aorto-iliac pseudoaneurysms - Hospital Kuala Lumpur experience

Khang NC, Zainal AA

Med J Malaysia, 2016 02;71(1):17-22.
PMID: 27130738

BACKGROUND: This is a single institutional review of aortoiliac pseudoaneurysm of various aetiologies managed with endovascular stent graft repair.

METHODS: From 2009 to 2014, 16 patients had endovascular stent graft inserted for pseudoaneurysm of the thoracic aorta, abdominal aorta and iliac arteries in Hospital Kuala Lumpur. Co-morbidity, causative agents, in-hospital mortality, complications and outcomes were examined.

RESULTS: The average age was 59.1 years (range 36-77). Comorbidities include hypertension, diabetes mellitus, tuberculosis, prior infection and previous open aneurysmal repair. All patients had raised WBC (>10.0x10(9) /L), ESR or Creactive protein on admission while 50% of patients had fever. Blood cultures were positive in 4 patients. All patients were given antibiotics. Only one in-hospital mortality was noted at day-47 post-procedure. Two patients died of aortoenteric fistula at district hospital eight and 16 months later. One patient died of chronic graft infection two years later. One died of unrelated cause. One patient developed type IB endoleak from internal iliac artery two years later and surgical ligation was performed. The average follow up was 15.8 months.

CONCLUSION: Endovascular stent graft repair for pseudoaneurysm is a viable option compared to open surgery. It is less invasive, has lower operative morbidity and fair outcomes. However, some cases may be due to inflammatory aortitis instead of infective pseudoaneurysm, given the frequent culture-negative results. In order to obtain high yield of bacteria culture for infected pseudoaneurysm, open repair with tissue culture is still the main mode of treatment especially for patients with low comorbidity.

Matched MeSH terms: Stents*
Fulltext Transradial coronary angioplasty and stenting--immediate results and 3-month clinical follow-up in the first 50 patients performed at the National Heart Institute

Pillay D, Lam KH, Muda MN, Hamid Z

Med J Malaysia, 2000 Dec;55(4):467-72.
PMID: 11221159

Aim: To explore the safety and feasibility of coronary angioplasty and stenting via the radial artery in a heterogenous group of patients and to report the immediate and 3-month clinical follow-up.
Background: The use of the transradial approach for coronary angiography was first described by Lucien Campeau in 1989. Based on the favorable initial results, this technique has gained widespread acceptance worldwide. Ferdinand Kiemeneij’s work in transradial angioplasty and stenting has taken invasive cardiology into the exciting new era of “minimally invasive coronary intervention”.
Methods and results: Fifty consecutive patients underwent Transradial Percutaneous Transluminal Coronary Angioplasty (PTCA) with or without stenting from mid March 98 – December 98. The right radial approach was utilized in 41 patients (80%) while the left in 9 patients. Ninety percent of the procedures was done on an adhoc basis. Diabetes mellitus was present in 38% of patients. Eighty percent of the patients had unstable angina pectoris and 60% had a prior history of acute myocardial infarction. The commonest vessel involved was the LAD (41%) and type B lesions predominated (54%). PTCA was successful in 96%. One patient had a total LAD occlusion, which could not be wired, and another developed severe spasm during catheter manipulation. The latter ad successful PTCA via the right femoral route Stents were utilized in 57% of patients. The commonest indication for stenting was suboptimal PTCA results (89%) and dissection (14%). There was no stent embolization and all stents were successfully deployed (100%). One patient developed acute stent thrombosis necessitating repeat PTCA and another patient sustained an acute anteroseptal myocardial infarction 5 days post procedure as a result of subacute stent thrombosis and died. Two patients had successful primary PTCA. There was no bleeding or vascular complications. 60% of patients were treated on an outpatient basis. At 3-months follow up 1 patient required CABG’s for disease progression. Three patients had absent radial pulses without adverse consequence. No patient required repeat PTCA at follow up.
Conclusion: In summary, adhoc PTCA and stenting is safe and feasible in our patient population. A study on the cost effectiveness of the procedure compared to conventional femoral PTCA is warranted.

Matched MeSH terms: Stents*
Fulltext Airway stenting for tracheal stenosis

Eng JB, Hooi LN, Ng SH

Med J Malaysia, 1999 Mar;54(1):125-7.
PMID: 10972017

Patients with upper airway obstruction from malignant disease are difficult to manage. A 62 year old patient presented with stridor and was found to have an upper tracheal tumour. Bronchoscopy, dilatation and stenting were performed successfully. The techniques and indications for the use of dynamic airway stent are discussed.

Matched MeSH terms: Stents*
Fulltext Coronary stents in the management of coronary artery disease review of first 100 stents

Ng SC, Sawatt C, Foo LK, Hitam O, Khor PG, Lee YK

Med J Malaysia, 1996 Mar;51(1):75-9.
PMID: 10967983

This is a review of the first 100 coronary stents implanted for the indications of PTCA restenosis, acute or threatened closure and De Novo lesions. The success rates were high and complications rates were low. Subacute stent thrombosis rates were low and stenting for De Novo lesions in > 3.0 mm arteries provide the best short and long term results. Six months restenosis rate was low. Stent assisted high pressure balloon angioplasty is an important advance.

Matched MeSH terms: Stents*
Intravesical stent position as a predictor of quality of life in patients with indwelling ureteral stent

Inn FX, Ahmed N, Hou LG, Abidin ZAZ, Yi LL, Zainuddin ZM

Int Urol Nephrol, 2019 Nov;51(11):1949-1953.
PMID: 31441009 DOI: 10.1007/s11255-019-02262-7

PURPOSE: The internal drainage provided by a ureteral stent helps with the relief and prevention of ureteral obstruction. By definition, correct stent placement is one with a complete loop in both the renal pelvis and bladder. This prevents stent migration proximally or distally despite urinary flow, patient movement, and ureteral peristalsis.
METHODS: We performed a comparative prospective cross-sectional study assessing the impact of intravesical stent position on the quality of life in 46 patients with a ureteral stent. This is done using the Ureteral Stent Symptom Questionnaire (USSQ).
RESULTS: 52.5% of patients had an ipsilateral positioned intravesical stent, while the remaining had their stent positioned contralaterally. Intravesical stent position significantly influenced the quality of life. The USSQ score was worse for the contralateral group. Subscore analysis found that urinary symptoms and body pain index contribute significantly to the morbidity. Majority of patients in the ipsilateral group reported no discomfort as compared to the contralateral group.
CONCLUSIONS: To the best of our knowledge, this is the first study assessing the impact of intravesical stent position on the quality of life in the Asian population. Intravesical stent position has a significant influence on patient's morbidity and quality of life in particular towards their urinary irritative symptoms and body pain. It is imperative to ensure correct distal placement of ureteric stent that does not cross the midline to the contralateral site. We believe that the USSQ should be used in daily clinical practice in assessing the symptoms related to indwelling ureteric stents.

Matched MeSH terms: Stents*
Sonographically guided removal of a double J ureteral stent in an infant

Jutti RC, Subramaniam R, Balsingh D, Qureshi AM

J Clin Ultrasound, 2002 May;30(4):232-5.
PMID: 11981933 DOI: 10.1002/jcu.10062

A 2-month-old male infant with a prenatally diagnosed obstruction of the ureteropelvic junction underwent a dismembered Anderson-Hynes pyeloplasty. A transanastomotic double J ureteral stent was placed between the renal pelvis and the urinary bladder. This report describes the subsequent removal of the double J ureteral stent from the patient's urinary bladder without the aid of a cystoscope: a rigid biopsy forceps was introduced trans-urethrally into the urinary bladder, and the stent was removed with sonographic guidance. Removal of a ureteral stent with sonographic guidance has not been previously reported in infants. This technique may be particularly useful in developing countries, where appropriate-sized cystoscopes and accessories may not be available.

Matched MeSH terms: Stents*
Degradation behavior of biodegradable Fe35Mn alloy stents

Sing NB, Mostavan A, Hamzah E, Mantovani D, Hermawan H

J Biomed Mater Res B Appl Biomater, 2015 Apr;103(3):572-7.
PMID: 24954069 DOI: 10.1002/jbm.b.33242

This article reports a degradation study that was done on stent prototypes made of biodegradable Fe35Mn alloy in a simulated human coronary arterial condition. The stent degradation was observed for a short-term period from 0.5 to 168 h, which simulates the early period of stenting procedure. Potentiodynamic polarization and electrochemical impedance spectroscopy were used to quantify degradation rate and surface property of the stents. Results showed that signs of degradation were visible on both crimped and expanded stents after 1 h of test, mostly located on the stent's curvatures. The degradation rate of stent was higher compared to that of the original alloy, indicating the surface altering effect of stent fabrication processing to degradation. A single oxide layer was formed and detected as a porous structure with capacitive behavior. Expanded stents exhibited lower polarization resistance compared to the nonexpanded ones, indicating the cold work effect of expansion procedure to degradation.

Matched MeSH terms: Stents*
Placement of removable metal biliary stent in post-orthotopic liver transplantation anastomotic stricture

Tee HP, James MW, Kaffes AJ

World J Gastroenterol, 2010 Jul 28;16(28):3597-600.
PMID: 20653071

Postoperative biliary strictures are the most common cause of benign biliary stricture in Western countries, secondary to either operative injury or bile duct anastomotic stricture following orthotopic liver transplantation (OLT). Surgery or endoscopic interventions are the mainstay of treatment for benign biliary strictures. We aim to report the outcome of 2 patients with refractory anastomotic biliary stricture post-OLT, who had successful temporary placement of a prototype removable covered self-expandable metal stent (RCSEMS). These 2 patients (both men, aged 44 and 53 years) were given temporary placement of a prototype RCSEMS (8.5 Fr gauge delivery system, 8 mm x 40 mm stent dimensions) in the common bile duct across the biliary stricture. There was no morbidity associated with stent placement and removal in these 2 cases. Clinical parameters improved after the RCSEMS placement. Long-term biliary patency was achieved in both the patients. No further biliary intervention was required within 14 and 18 mo follow-up after stent removal.

Matched MeSH terms: Stents*
Definite stent thrombosis among Malaysian population: predictors and insights of mechanisms from intracoronary imaging

Lim KC, Yap LB, Amin AN

Med J Malaysia, 2020 09;75(5):472-478.
PMID: 32918412

INTRODUCTION: Stent thrombosis (ST) is an uncommon, but significant complication following angioplasty. We aimed to examine the predictors, clinical outcomes and mechanism of definite ST cases among patients who underwent percutaneous coronary intervention (PCI).
METHODS: This was a retrospective observational registry of 14,935 patients from the year 2011 till 2015. Clinical characteristics, clinical outcome and intracoronary imaging data were recorded in all the patients. The SPSS Statistic version 24 was used for statistical analysis. The Cox regression hazard model was used to report calculate the hazard ratio (HR) with a 95% confidence interval (95%CI). Independent predictors of ST were identified by univariate logistic regression analysis. Variables that showed a statistically significant effect in univariate analyses were entered in a multivariate Cox proportional hazards model. A p-value<0.05 was regarded as significant.
RESULTS: The incidence of definite ST was 0.25% (37 out of 14935 patients). 75% of ST group patients presented with ST elevation myocardial infarction (75% vs. 19.8%, p<0.01). There was higher mortality among patients with ST when compared to the group without ST (Hazard Ratio, HR=10.69, 95%CI: 1.13, 100). Two independent predictors of ST were 1) previous history of acute myocardial infarction (HR=2.36, 95%CI: 1.19, 4.70) and 2) PCI in the context of acute coronary syndrome when compared to elective PCI (HR=37, 95%CI: 15.7, 91.5). Examination of 19 ST cases with intracoronary imaging identified nine cases (47%) of underexpanded stents and five cases (26%) of malopposition of stents.
CONCLUSIONS: ST is associated with high mortality. PCI in acute coronary syndrome setting and a previous history of acute myocardial infarction were significant predictors for ST. Intracoronary imaging identified stent underexpansion and malopposition as common reasons for ST. In cases where the risk of ST is high, the use of intracoronary imaging guided PCI is recommended.

Matched MeSH terms: Stents/adverse effects*
Fulltext Drug-coated balloon treatment in coronary artery disease: Recommendations from an Asia-Pacific Consensus Group

Her AY, Shin ES, Bang LH, Nuruddin AA, Tang Q, Hsieh IC, et al.

Cardiol J, 2021;28(1):136-149.
PMID: 31565793 DOI: 10.5603/CJ.a2019.0093

Coronary artery disease (CAD) is currently the leading cause of death globally, and the prevalence of this disease is growing more rapidly in the Asia-Pacific region than in Western countries. Although the use of metal coronary stents has rapidly increased thanks to the advancement of safety and efficacy of newer generation drug eluting stent (DES), patients are still negatively affected by some the inherent limitations of this type of treatment, such as stent thrombosis or restenosis, including neoatherosclerosis, and the obligatory use of dual antiplatelet therapy (DAPT) with unknown optimal duration. Drug-coated balloon (DCB) treatment is based on a leave-nothing-behind concept and therefore it is not limited by stent thrombosis and long-term DAPT; it directly delivers an anti-proliferative drug which is coated on a balloon after improving coronary blood flow. At present, DCB treatment is recommended as the first-line treatment option in metal stent-related restenosis linked to DES and bare metal stent. For de novo coronary lesions, the application of DCB treatment is extended further, for conditions such as small vessel disease, bifurcation lesions, and chronic total occlusion lesions, and others. Recently, several reports have suggested that fractional flow reserve guided DCB application was safe for larger coronary artery lesions and showed good long-term outcomes. Therefore, the aim of these recommendations of the consensus group was to provide adequate guidelines for patients with CAD based on objective evidence, and to extend the application of DCB to a wider variety of coronary diseases and guide their most effective and correct use in actual clinical practice.

Matched MeSH terms: Drug-Eluting Stents*
Guidezilla guide extension catheter enhances the delivery of bioresorbable vascular scaffold in an anomalous coronary artery

Yew KL

Int J Cardiol, 2016 Nov 15;223:239-241.
PMID: 27541663 DOI: 10.1016/j.ijcard.2016.07.299
Matched MeSH terms: Stents*

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