Home About us Contact
|
Home About us Contact | ||
|
|
||
Implantation Procedure (implantation + procedure)
Selected AbstractsGene therapy for haemophilia,yes, but,with non-viral vectors?HAEMOPHILIA, Issue 3 2009A. LIRAS Summary., High-purity plasma-derived and recombinant factors are currently safe and efficient treatment for haemophilia. The mid-term future of haemophilia treatment will involve the use of modified recombinant factors to achieve advantages such as decreased immunogenicity in inhibitor formation and enhanced efficacy as a result of their longer half-life. In the long-term, gene therapy and cell therapy strategies will have to be considered. Achievements in cell therapy to date have been using embryonic stem cells and hepatic sinusoidal endothelial cells. Current gene therapy strategies for haemophilia are based on gene transfer using adeno-associated viruses and non-viral vectors. Gene therapy for haemophilia is justified because it is a chronic disease and because a very regular factor infusion is required that may involve fatal risks and because it is very expensive. Haemophilia is a very good candidate for use of gene therapy protocols because it is a monogenic disease, and even low expression is able to achieve reversion from a severe to a moderate phenotype. The current trends in haemophilia using adeno-associated viral vectors are safe but also involve immunogenicity problems. The other alternatives are non-viral vectors. There have been in recent years relevant advances in non-viral transfection that raise hope for considering this possibility. Several research groups are opting for this experimental alternative. An expression over 5%, representing a moderate phenotype, for a few months with a high safety, regarding vector, transfected cells, and implantation procedure, would already be a great success. This may represent an intermediate protocol in which the expression levels and times obtained are lower and shorter respectively as compared to viral vectors, but which provide a potential greater patient safety. This may more readily win acceptance among both patients and haematologists because fatal events in the past due to HIV/HCV infection may constrain the implementation of viruses as vectors. [source] Toward an Implantable Wireless Cardiac Monitoring Platform Integrated with an FDA-Approved Cardiovascular StentJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 5 2009ERIC Y. CHOW Ph.D. Continuous monitoring of blood pressure from a minimally invasive device in the pulmonary artery can serve as a diagnostic and early warning system for cardiac health. The foremost challenge in such a device is the wireless transfer of data and power from within the blood vessel to an external device while maintaining unrestricted flow through the artery. We present a miniaturized system, which is attached to the outer surface of a regular or drug-eluting FDA-approved stent. When expanded, the stent maintains a patent vessel lumen while allowing contact between the electronic sensors and the blood supply. The stent-based antenna can be used for both wireless telemetry and power transfer for the implanted electronics. Using the stent platform as both a radiating antenna and a structural support allows us to take advantage of an FDA-approved device whose safety and surgical procedure are well established. The electronics package has been reduced to an area of less than 1 mm2, with a thickness under 300 ,m. A minimally invasive implantation procedure allows the delivery of the stent-based implant in nearly any major vessel of the body. This article describes an initial prototype with two stents configured as a single dipole, a 2.4-GHz transmitter microchip, and a battery, and validates transcutaneous transmission through ex vivo and in vivo porcine studies. The results demonstrate the feasibility of a stent-based wireless platform for continuous monitoring of blood pressure. [source] Spinal Cord Stimulation for the Treatment of Chronic Pain in Patients with Lumbar Spinal StenosisNEUROMODULATION, Issue 4 2010Amedeo Costantini MD Objective:, Chronic back and leg pain associated with lumbar spinal stenosis (LSS) is common in the elderly. Surgical decompression is usually performed when conservative treatments fail. We present an evaluation of the long-term outcome of patients suffering from symptomatic LSS treated with spinal cord stimulation (SCS). Materials and Methods:, Data were collected prospectively in three independent registries in three European centers. Pooled data were analyzed retrospectively. Changes in pain intensity, functional status, and analgesic medication were compared at baseline and at the last available follow-up. Demographic data as well as details regarding the implantation procedure and any adverse events were systematically recorded. Results:, Data were recorded in 69 patients with a mean follow-up period of 27 months. All patients showed clinically and statistically significant improvement in pain relief, the visual analog scale decreasing from 7.4 ± 2.3 to 2.8 ± 2.4 (p < 0.05). The use of analgesic medication decreased and the functional status improved. Conclusion:, Spinal cord stimulation seems to be effective in the treatment of patients suffering from chronic pain associated with LSS. Being less invasive and reversible, SCS should be considered before surgical decompression, particularly in patients with increased risks associated with back surgery. [source] Implantable Cardioverter Defibrillator-Related Complications in the Pediatric PopulationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2009MAULLY J. SHAH M.B.B.S. Background: The recognition that implantable cardioverter-defibrillator (ICD) therapy in children can prolong life coupled with the development of smaller devices and transvenous lead technology has increased the number of ICDs implanted in children and young adults. Methods: ICD complications in the pediatric population are reviewed. Results: ICD complications in the pediatric population include those related to the implantation procedure, the ICD system, as well as psychosocial issues. Inappropriate ICD therapy and ICD lead failures are the most frequent complications. Conclusion: Identifying complications is the prerequisite for advances in ICD technology and effective management strategies need to be developed to avoid their recurrence. [source] Clinical Predictors of Defibrillation Thresholds with an Active Pectoral Pulse Generator Lead SystemPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2002DENICE M. HODGSON HODGSON, D.M., et al.: Clinical Predictors of Defibrillation Thresholds with an Active Pectoral Pulse Generator Lead System. Active pectoral pulse generators are used routinely for initial ICD placement because they reduce DFTs and simplify the implantation procedure. Despite the common use of these systems, little is known regarding the clinical predictors of defibrillation efficacy with active pulse generator lead configurations. Such predictors would be helpful to identify patients likely to require higher output devices or more complicated implantations. This was a prospective evaluation of DFT using a uniform testing protocol in 102 consecutive patients with an active pectoral can and dual coil transvenous lead. For each patient, the DFT was measured with a step-down protocol. In addition, 34 parameters were assessed including standard clinical echocardiographic and radiographic measures. Multivariate stepwise regression analysis was performed to identify independent predictors of the DFT. The mean DFT was 9.3 ± 4.6 J and 93% (95/102) of patients had a DFT , 15 J. The QRS duration, interventricular septum thickness, left ventricular mass, and mass index were significant but weak (R < 0.3) univariate predictors of DFT. The left ventricular mass was the only independent predictor by multivariate analysis, but this parameter accounted for < 5% of the variability of DFT measured (adjusted R2= 0.047, P = 0.017). The authors concluded that an acceptable DFT (< 15 J) is observed in > 90% of patients with this dual coil and active pectoral can lead system. Clinical factors are of limited use for predicting DFTs and identifying those patients who will have high thresholds. [source] Vascular closure staples reduce intimal hyperplasia in prosthesis implantationANZ JOURNAL OF SURGERY, Issue 12 2002Wayne J. Hawthorne Background: Vascular surgery, like the various other surgical specialities, has seen an increasing demand toward faster and more minimally invasive procedures. One such need is to create a reliable vascular anastomosis that is faster, easier and less damaging to the tissue. The vascular closure staples (VCS*) device provides such characteristics but, to date, no studies have investigated its effectiveness in reducing intimal hyperplasia when used for vascular prosthesis implantation. The present study evaluated its effectiveness compared with suturing of a graft in vascular prosthesis implantation. Methods: Twelve female Merino sheep underwent gelatin sealed Dacron patch graft implantation into the left and right common carotid artery. Grafts were randomly allocated so that one carotid artery and graft was anastomosed using sutures and the other with VCS*. The two techniques were compared for operation time, clip/suture numbers and blood loss during the implantation procedure. After a 4-week period, the sheep were killed and the grafts were harvested for intimal hyperplasia (IH) assessment. Results: There was a significant reduction in the amount of IH seen in the VCS* group (mean ± SD: 0.278 ± 0.079 mm2/mm) when compared with the sutured group (0.575 ± 0.331 mm2/mm) (P < 0.05). There was also significant reduction in anastomosis time (mean ± SD: 14 ± 4.4 min) and fewer points of contact (23 ± 1.4) using the VCS* compared with suturing (22 ± 3.2 min, P < 0.01; 27 ± 3.3, P < 0.05, respectively). Conclusions: In this model, the VCS* shows several distinct advantages over suturing with significant time saving at operation and, most importantly, the reduction of IH seen at 1 month. [source] Investigation of particular surgical steps in epiretinal prostheses implantation procedure in pigsACTA OPHTHALMOLOGICA, Issue 2009D IVASTINOVIC Purpose Proliferative vitreoretinopathy (PVR) is known a known complication of implantation of epiretinal prostheses in porcine eyes using our combined surgical procedure of vitrectomy, lensectomy, large scleral incision and retinal tack insertion. The aim of the present experimental study is to investigate the intraocular reaction to particular parts of the epiretinal prostheses implantation procedure in pigs. Methods 15 pigs were divided into 3 groups. Group 1 (n=6) underwent vitrectomy, lensectomy, insertion of inactive epiretinal prosthesis through a scleral incision and fixation to the posterior pole with a retinal tack. In group 2 (n=5) vitrectomy, scleral incision and retinal tack insertion were performed. Group 3 (n=4) received vitrectomy, scleral incision and insertion of a shortened prosthesis into the vitreous cavity. The follow up was 4 weeks. Results PVR was observed in all eyes of group 1 and in one eye of the group 3 with unintentional perforation of the lens capsule by the shortened implant. In all other eyes funduscopy revealed no clinical pathology. Conclusion Our results indicate that lensectomy is the key stimulus for PVR in porcine eyes while other steps of the implantation procedure are well tolerated. Though pigs do not seem to be a reactive animal model, lens manipulation should be avoided in the surgical procedure for the implantation of retinal prostheses. [source] Stent implantation in variant angina refractory to medical treatmentCLINICAL CARDIOLOGY, Issue 12 2006Dr Vicens Martí M.D. Abstract Background Vasospastic angina usually responds well to medical treatment. Hypothesis The present study describes our experience in patients who received a coronary stent because of recurrent variant angina refractory to medical treatment and evaluates stent implantation as an alternative treatment. Materials and methods Between March 1998 and February 2005, recurrent variant angina was diagnosed in 22 patients admitted to our coronary care unit. Of these, five patients (22.7%), were refractory to pharmacologic treatment. Coronary angiography and coronary stents were indicated. Clinical follow-up was 29 ± 6 months. Results Stenting was performed during diagnostic coronary angiography in two patients. In the other three patients, the stent was implanted 24,48 h later. We observed coronary spasm recurrences proximal or distal to the stent in four patients,two during the stent implantation procedure and the other two in the coronary care unit within 48 h post angioplasty. Three patients where treated with additional stenting and the fourth patient improved with pharmacologic treatment. During follow-up three patients remained asymptomatic. The fourth patient had diffuse in-stent restenosis in the third month, and the fifth patient showed a de novo lesion in the treated segment 2 years later. Conclusions Stent implantation in patients with recurrent variant angina refractory to medical treatment may be an alternative treatment in carefully selected, clinically unstable patients. Spasm recurrences may occur in other segments of the treated artery, probably due to the diffuse nature of the disease. Immediate and continued surveillance is recommended because of the risk of adverse clinical events. Copyright © 2006 Wiley Periodicals, Inc. Wiley Periodicals, Inc. [source] | ||||||||||