Device Size (device + size)

Distribution by Scientific Domains

Selected Abstracts

Transcatheter Intracardiac Echocardiography-Assisted Closure of Interatrial Shunts: Complications and Midterm Follow-Up

Gianluca Rigatelli M.D.
Objective: It has been suggested that intracardiac echocardiography (ICE) improves the safety and effectiveness of transcatheter device-based closure of interatrial shunts, but the impact of this technique on midterm follow-up is unknown. We sought to prospectively evaluate midterm follow-up results of ICE-aided transcatheter closure of interatrial shunts in adults. Methods: Over a 48-month period, we prospectively enrolled 140 consecutive patients (mean age 43 ± 15. 5 years, 98 females) who had been referred to our center for catheter-based closure of interatrial shunts. All patients were screened with transesophageal echocardiography (TEE) before the operation. Patients who met the inclusion criteria underwent ICE study and attempted closure. Immediate success rates, predischarge occlusion rates, complication rates, as well as fluoroscopy and procedural times, patients' radiological exposure, midterm complication rates, and midterm occlusion rates were evaluated. Results: One hundred patients out of 140 (71.4%) underwent an attempt at transcatheter closure. After ICE study and measurements, the TEE-planned device type and size was changed in 31 patients with patent foramen ovale whereas the TEE-planned device size was changed in 41 patients with atrial septal defect (globally 72%). Procedural success rate, predischarge occlusion rate, and complication rate were 99, 90.7, and 12%, respectively. On mean follow-up of 36.6 ± 14.8 months the follow-up occlusion rate was 96.5%. No aortic erosion or device thrombosis was observed. Conclusions: ICE-guided interatrial shunt transcatheter closure is safe and effective and appears to have excellent midterm results thus avoiding the complications caused by device oversizing, such as aortic erosion and device thrombosis. [source]

Figulla ASD Occluder versus Amplatzer Septal Occluder: A Comparative Study on Validation of a Novel Device for Percutaneous Closure of Atrial Septal Defects

Objectives: Occlutech Figulla ASD Occluder (FSO) is an alternative device to Amplatzer Septal Occluder (ASO) with some structural innovations including increased flexibility, minimizing the amount of material implanted, and absence of the left atrial clamp. We aimed to report our experiences with FSO and compare the outcomes of this novel device versus ASO. Interventions: Between December 2005 and February 2009, 75 patients diagnosed with secundum atrial septal defects underwent transcatheter closure. The FSO device was used in 33 patients, and the ASO was used in 42. Results: Patient characteristics, stretch size of the defect, device left disc size, procedure, and fluoroscopy time were similar between the groups. However, the difference between device waist size and stretched diameter of the defect was significantly higher, and device delivery sheath was significantly larger in FSO group and device left disc size was significantly lower in the FSO group. In all subjects, the residual shunt was small to trivial during follow-up and the reduction in prevalence of residual shunt with time was similar in both groups (P = 0.68). We found no differences in complication rate between the two devices; however, device embolization to the pulmonary bifurcation in one patient was recorded as major complication in FSO device group. Conclusions: Both devices are clinically safe and effective in ASD closure. FSO device has similar outcomes when compared to ASO device. Difficulties in selecting the correct device size in larger defects and larger venous sheath requirement need to be evaluated in further studies. [source]

Optical characterization of GaN microcavity fabricated by wet etching

C.-Y. Lu
Abstract We report a novel technique to fabricate gallium nitride (GaN) microcavities by combining the methods of photo-enhanced wet chemical oxidation and crystallographic etching. Such GaN microcavities exhibit mirror-like vertical facets composing of {1100}GaN and various gemoetry of hexagonal, trigonal and cylindrical shapes. The emission spectra of the GaN micro-cavities are found in resonance with the whispering gallery (WG) modes when pumped with a 266 nm Nd:YAG laser. The signatures of GaN microcavities were further characterized by an increase of the WG mode spacing with the reduced device size and suppression of the side mode emission intensity with pump intensity. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Catheter-based closure of atrial septal defects in the oval fossa with the Amplatzer® device in patients in their first or second year of life,

G. Fischer MD
Abstract Objective: To assess feasibility, safety, and efficacy of the use of Amplatzer® occluders in closure of atrial septal defects (ASD) in children in the first 2 years of life. Background: Although scattered reports on such closure have been published, no agreement consists on the policy. Methods: In 654 patients of all ages, closure was achieved in 632 (96.6%). Data were analyzed retrospectively in all 71 children where an attempt had been made to close the ASD before their second birthday. Results: Median age and body weight were 17.2 months (range 3.9,23.8) and 10.0 kg (range 3.8,14.5), respectively. Median fluoroscopy time was 13.6 min and median device size 15 mm. Successful closure was achieved in 68 children (95.8%). Three times the procedure was aborted: in one, the device repeatedly straddled the septum; in the other two, a small left atrium restricted the movement of the left-sided disc. One device embolized and was reimplanted after retrieval. One infant with multiple disorders died 6 days after closure from acute sepsis probably unrelated to the procedure. No other complications occurred. Only trivial shunts closing with time were registered during follow-up. Symptomatic patients profited markedly from closure. Conclusion: The results and complications of ASD closure with the Amplatzer® device in patients in their first 2 years of life compare favorably with procedures in older patients, provided that the size of the septum and the dimensions in the left atrium are taken into consideration when selecting the size of the device. © 2009 Wiley-Liss, Inc. [source]

Transcatheter closure of perimembranous ventricular septal defects using the amplatzer membranous VSD occluder: Immediate and midterm results of an international registry

Ralf Holzer MD
Abstract Objective: To report the immediate and midterm results of transcatheter closure of perimembranous ventricular septal defect (PmVSD) using the Amplatzer membranous VSD occluder (AMVSD). Methods: Between April 2002 and August 2004, 100 patients underwent an attempt of percutaneous device closure of PmVSD using the AMVSD in 24 international centers. The median age was 9.0 years (0.7,58 years) and the median weight was 27.5 kg (7,121 kg). Results: A device was successfully deployed in 93/100 (93%) patients. Reasons for procedural failure were an increased gradient across the left ventricle outflow tract in one patient, aortic regurgitation in 2 patients, and inability to securely position the device in 4 patients. The median VSD size by TEE was 7.0 mm (1.5,13 mm), median device size 10 mm (4,16 mm) and median fluoroscopy time 22.1 min (8.9,96.0 min). Weight below 10 kg (P = 0.0392), inlet extension of the VSD (P = 0.0139) and aortic cusp prolapse into the VSD (P = 0.0084) were significantly associated with a lower procedural success. Patients have been followed up for a median of 182 days (1,763 days). There were no procedure-related deaths. Complications were encountered in 29/100 (29%) patients, including rhythm or conduction anomalies in 13 patients (two with complete heart block requiring permanent pacemaker implantation), new or increased aortic (9 patients) or tricuspid (9 patients) regurgitation, most of which were classified as trivial or mild. Patients with a weight below 10 kg had a significantly higher incidence of adverse events than patients with a weight above 10 kg (58.3% versus 25.0%, P = 0.0285). Immediately after device release complete closure of the defect was present in 54/93 (58.1%) patients, increasing to 46/55 (83.6%) patients at 6-months follow-up (P = 0.0012). Left ventricle end-diastolic diameter decreased from a median of 44 mm prior to device closure to a median of 39 mm at 6-months postprocedure (P = 0.0015). Conclusion: Closure of PmVSDs using the AMVSD occluder is safe and effective. However, longer follow-up period is warranted prior to the wide spread use of this device. © 2006 Wiley-Liss, Inc. [source]

Use of balloon pull-through technique to assist in CardioSEAL device closure of patent foramen ovale

Kavitha Chintala MD
Abstract CardioSEAL device closure of patent foramen ovale (PFO) has been advocated for the treatment of patients with cryptogenic stroke. Using the standard delivery technique, partial deployment of the CardioSEAL device can occur, especially in patients with a thick septum secundum and/or long PFO tunnel. We hypothesized that using a left atrial-to-right atrial balloon pull-through to make the septum primum incompetent would result in improved final device position regardless of septal thickness or tunnel length. Catheterization reports, cineangiograms, and transesophageal echocardiograms of 51 patients who underwent CardioSEAL device closure of PFO between March 2000 and August 2002 were retrospectively reviewed. Group 1 (n = 21) included patients with CardioSEAL placement using the standard technique and group 2 (n = 30) included patients with CardioSEAL placement using the balloon pull-through technique. There were no differences between the groups in terms of age (43.6 vs. 45.3 years; P = NS), weight (83.3 vs. 89.9 kg; P = NS), septum secundum thickness (6.4 vs. 7.0 mm; P = NS), PFO tunnel length (15.5 vs. 13.1 mm; P = NS), or device size. In group 1, 4/21 (19%) had partial deployment of the CardioSEAL device, while in group 2, no partial CardioSEAL deployment (0/30) was observed. No complications were associated with the balloon pull-through technique. We conclude that the left atrial-to-right atrial balloon pull-through technique is safe and may allow for better final position of the CardioSEAL device during PFO closure. Catheter Cardiovasc Interv 2003;60:101,106. © 2003 Wiley,Liss, Inc. [source]

Transcatheter closure of very large (, 25 mm) atrial septal defects using the Amplatzer septal occluder

Bhava Ramalingam Jawahar Kannan MD
Abstract Between June 1999 and September 2002, 45 patients (age, 34 ± 13 years; mean shunt ratio, 2.6 ± 0.6) underwent transcatheter atrial septal defect (ASD) closure at our institution with the Amplatzer septal occluder (mean device size, 31.4 ± 3 mm). Patients were selected by transesophageal echocardiography. The mean ASD dimension was 25.3 ± 3.7 mm and 33 (73%) patients had deficient anterior rim. Specific procedural details included the use of 13 or 14 Fr introducer sheaths and the right upper pulmonary vein approach if the conventional approach failed. There were two procedural failures, with device embolization in both (surgical retrieval in one, catheter retrieval in one). During follow-up (3,30 months; median, 16 months), one patient (59 years) with previous atrial flutter had pulmonary embolism and was managed with anticoagulation. Two patients developed symptomatic atrial flutter. Fluoroscopy time was 31.6 ± 19.5 min for the first 22 cases and 19.6 ± 11.4 min for the rest (P = 0.04). Transcatheter closure of large ASDs is technically feasible but careful long-term follow-up is needed to document its safety. Cathet Cardiovasc Intervent 2003;59:522,527. © 2003 Wiley-Liss, Inc. [source]

Textured Microstructure and Dielectric Properties Relationship of BaNd2Ti5O14 Thick Films Prepared by Electrophoretic Deposition

Zhi Fu
Abstract An alternative approach to tailor the temperature coefficient of permittivity (TC,r) of high Q dielectric BaO,Re2O3,TiO2 (Re: rare earth elements) thick films is presented. 10- to 80-µm-thick BaNd2Ti5O14 (BNT) films are fabricated by electrophoretic deposition on Pt foils under different processing conditions. Observed anisotropic grain growth is facilitated by constrained sintering. The increase of the sintering temperature increases markedly the aspect ratio of the grains, decreases the dielectric permittivity and TC,r changes from ,114 to +12,ppm °C,1. By controlling the sintering temperature, near-zero TC,r, high Q thick films can be fabricated with 45,<,,r,<,70. These findings are of technological relevance since they demonstrate that control of substrate constraint and sintering conditions can be used to control grain anisotropy and thus microwave properties of the BaO,Re2O3,TiO2. The thick films facilitate scaling to small device sizes for high frequency operation. Similar observations are expected in other microwave systems thus opening further technological opportunities. [source]

Mixing in Sub-micron Ducts

E.B. Nauman
Abstract This paper considers a class of fluidic devices, anticipated to become important in the near future, where characteristic channel dimensions are in the range 0.1 to 1.0 microns. Typical current applications of microfluidics have device sizes of 10 to 100 micron, this is sufficiently small to force laminar flow but not so small that molecular diffusion is a dominant factor. In the smaller devices contemplated here, diffusion is important and existing mixing strategies and correlations are no longer applicable. Novel results and interesting complexities are discussed for reactive, single and two phase flows in sub-micron channels. [source]