Transcatheter closure of secundum atrial septal defects with the new self-centering Amplatzer Septal Occluder.
AIMS: The study was set up to find out whether a new self-centering prosthesis for transcatheter closure of secundum atrial septal defects could overcome the disadvantages of previously described devices. METHODS AND RESULTS: Fifty-two consecutive patients with a significant atrial septal defect were considered for transcatheter closure with the Amplatzer Septal Occluder. The device, made of a Nitinol and polyester fabric mesh, provides a different approach to defect occlusion by stenting the atrial septal defect up to a stretched diameter of 26 mm. Three infants whose large defects were demonstrated on a transthoracic echocardiogram were excluded from transcatheter treatment. On transoesophageal echocardiography, 49 defects ranged from 6-26 mm, in one adult the defect measured 28 mm and this patient was excluded from attempted transcatheter closure. At cardiac catheterization in five further patients, devices were not implanted, in two because the stretched diameter exceeded 26 mm and in three the device was withdrawn because it was unstable or compromised the mitral valve. Thus, device closure was performed in 43 patients. At follow-up after 3 months the complete closure rate was 97%. CONCLUSION: The self-centering Amplatzer Septal Occluder is very efficient and user-friendly and offers interventional closure in 83% of an unselected group of patients presented with an atrial septal defect. (+info
New device for closure of muscular ventricular septal defects in a canine model.
BACKGROUND: Repair of muscular ventricular septal defects (MVSDs) has always been challenging to the surgeon. Long-term morbidity and mortality are significantly increased if the defects are closed via left ventriculotomy or if they are associated with other complex congenital anomalies. The purpose of this study was to close MVSDs with the Amplatz ventricular septal defect device. This device is constructed from 0.004-in nitinol wire mesh filled with polyester fibers. It is retrievable, repositionable, self-centering, and of low profile. METHODS AND RESULTS: MVSDs were created with the help of a sharp punch in 10 dogs. The location of the defects was anterior muscular (n=3), midmuscular (n=3), apical (n=3), and inlet muscular (n=1). The diameter of the defects ranged from 6 to 14 mm. All defects were closed in the catheterization laboratory. The device was placed with the help of transesophageal echocardiography and fluoroscopy. A 7F sheath was used to deploy the device from the right ventricular side in 8 and the left ventricular side in 2 dogs. Placement was successful in all animals. The complete closure rate was 30% (3/10) immediately after placement and 100% at 1-week follow-up. Pathological examination of the heart revealed complete endothelialization of the device in dogs killed after 3 months. CONCLUSIONS: The Amplatz ventricular septal defect device appears highly efficacious in closing MVSDs. The advantages include a small delivery sheath, complete retrievability before release, and the fact that it is self-centering and self-expanding, thereby making it an attractive option in smaller children. (+info
Origin of graphitic carbon and pentlandite in matrix olivines in the Allende meteorite.
Matrix olivines in the Allende carbonaceous chondrite are believed to have formed by condensation processes in the primitive solar nebula. However, transmission electron microscope observations of numerous matrix olivines show that they contain abundant, previously unrecognized, nanometer-sized inclusions of pentlandite and poorly graphitized carbon. Neither of these phases would have been stable at the high-temperature conditions required to condense iron-rich olivine in the solar nebula. The presence of these inclusions is consistent with formation of the olivines by parent body processes that involved overgrowth of fine-grained organic materials and sulfides in the precursor matrix materials. (+info
Further experience with transcatheter closure of the patent ductus arteriosus using the Amplatzer duct occluder.
OBJECTIVE: The aim of this study was to report further experience with transcatheter closure of the patent ductus arteriosus (PDA) using the Amplatzer duct occluder (ADO). BACKGROUND: The design of previously used devices is not ideal for this purpose, and their use has been associated with several drawbacks, especially in large PDAs. METHODS: Forty-three patients, aged 0.3 to 33 years (mean 6.4+/-6.7 years), with a moderate to large, type A to E PDA, underwent attempted transcatheter closure using the ADO. The device is a plug-shaped repositionable occluder made of 0.004-in. nitinol wire mesh. It is delivered through a 5F to 6F long sheath. The mean PDA diameter (at the pulmonary end) was 3.9+/-1.2 mm (range 2.2 to 8 mm). All patients had color flow echocardiographic follow-up (6 to 24 months) at 24 h, 1 and 3 months after closure, and at 6-month intervals thereafter. RESULTS: The mean ADO diameter was 6.1+/-1.4 mm (range 4 to 10 mm). Complete angiographic closure was seen in 40 of 43 patients (93%; 95% confidence interval [CI] 85.4% to 100%). The remaining three patients had a trivial angiographic shunt through the ADO. At 24 h, color flow mapping revealed no shunt in all patients. A 9F long sheath was required for repositioning of a misplaced 8-mm device into the pulmonary artery. The mean fluoroscopy time was 7.9+/-1.6 min (range 4.6 to 12 min). There were no complications. No obstruction of the descending aorta or the pulmonary artery branches was noted on Doppler follow-up studies. Neither thromboembolization nor hemolysis or device failure was encountered. CONCLUSIONS: Transcatheter closure using the ADO is an effective and safe therapy for the majority of patients with patency of the arterial duct. Further studies are required to establish long-term results in a larger patient population. (+info
Successful percutaneous endovascular treatment of a ruptured popliteal artery aneurysm.
A rupture of the popliteal artery is a rare but dangerous complication of aneurysmal disease. It accounts for 4% of all popliteal artery aneurysms encountered and threatens the loss of the extremity and, infrequently, is also life-threatening.(1) when this clinical entity is confronted, a prompt operative intervention is indispensable for increasing the chances of limb salvage. We report the first, to our knowledge, successful endovascular treatment of a ruptured popliteal artery aneurysm with a new polytetrafluoroethylene stent-graft in a patient who was unfit for a conventional surgical approach because of his severe pulmonary disease. (+info
Hard metal alveolitis accompanied by rheumatoid arthritis.
Hard metal lung diseases (HML) are rare, and complex to diagnose. We describe the case of a patient with allergic alveolitis accompanied by rheumatoid arthritis. A sharpener of hard metal by trade, our patient was a 45-year-old, nonsmoking Caucasian female who experienced symptoms of cough and phlegm, and dyspnea on exertion. Preliminary lung findings were inspiratory rales in both basal areas, decreased diffusion capacity and a radiological picture resembling sarcoidosis. A high-resolution computed tomography scan indicated patchy alveolitis as well. An open lung biopsy revealed non-necrotizing granulomas consisting of epitheloid cells and surrounded by lymphocytes, plasma cells and a few eosinophils. These cells also occupied the thickened alveolar interstitium. Macrophages in the alveolar spaces, some of them multinuclear, contained dust particles. Hard metal alveolitis is clinically well known and, in this patient, has been described histologically. After the patient had quit working with hard metal and following corticosteroid therapy, pulmonary symptoms and signs were relieved. During this recovery period, however, she contracted rheumatoid arthritis. (+info
Endovascular stenting for carotid artery stenosis: preliminary experience using the shape-memory- alloy-recoverable-technology (SMART) stent.
We describe our initial clinical experience using the newly available self-expanding, Nitinol, shape-memory-, alloy-recoverable-technology (SMART) stent in treating carotid artery occlusive disease. Five stents were used in four carotid arteries in four consecutive patients with carotid stenosis of at least 70%. Technical success (<20% residual stenosis) was achieved in all cases. No procedural complications specifically related to use of the SMART stent were encountered. All patients remained symptom-free, with no evidence of transient ischemic attacks or new strokes during an average follow-up period of 6 months. Excellent performance of the SMART stent for the endovascular treatment of carotid artery stenosis has been shown based on our early experience. Validation with greater numbers and longer-term follow-up is required. The specific technical characteristics, potential advantages, and disadvantages of this stent are discussed and compared with other currently used carotid artery stents. (+info
Nitinol - its use in vascular surgery and other applications.
OBJECTIVES: to describe the physical properties of shape-memory alloys and the surgical, scientific and commercial applications of nitinol, in particular. DESIGN AND METHODS: 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. RESULTS: 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. CONCLUSIONS: further research into shape-memory alloys from scientific and commercial groups should widen their use in vascular and endovascular surgery. (+info