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At least 433 records · Page 24Linked to original sources
PubMed2006

Current status of carotid artery stenting.

This Clinical Update summarizes the results of larger case series, industry-sponsored registries, and randomized trials of carotid artery stenting (CAS). In >20 case series that studied >24,000 patients undergoing CAS, 51% of patients were symptomatic, most procedures (97%) resulted in successful stent deployment, and 30-day stroke rates varied from 1% to 8%, with a trend toward lower rates as experience and embolic protection device (EPD) use increased. In 12 industry-sponsored registries (none were published in peer-reviewed journals), 30-day stroke rates varied from 2% to 7%, and 30-day combined adverse events, including stroke, death, and myocardial infarction, were 3% to 9%. More than 12 randomized trials comparing CAS and carotid endarterectomy (CEA) have been initiated since 1998. Results have varied over time, depending on the population studied and the technology used. However, the largest and most recent results of the completed SAPPHIRE trial in high-risk patients undergoing CAS with the use of EPDs demonstrated that CAS is at least not inferior to CEA, with a 1-year combined adverse event rate of 12% for CAS and 20% for CEA (P = .05). Other ongoing trials will address not only whether CAS could be superior to CEA in high-risk patients but also, more importantly, whether CAS is beneficial in other subgroups, such as low-risk and asymptomatic patients.

Angioplasty↗
PubMed2006

Sheath-assisted controlled deployment technique for Excluder bifurcated main body.

The W. L. Gore Excluder bifurcated device uses a single-action deployment mechanism with an expanded polytetrafluoroethylene string that is stitched to an outer jacket constraining the nitinol self-expanding stent-graft. Under certain anatomic conditions of the proximal neck, the deployment angle of the proximal stent-graft can be difficult to predict and result in the device being seated caudal to the intended landing site just below the lowermost renal artery. This article describes a technique of controlled deployment of the Excluder device where the top of the main bifurcated device is "flowered" by slowly pulling the deployment string while being buttressed by an introducer sheath to prevent premature deployment and allow longitudinal positioning of the device. This technique could be used when a more gradual deployment of the Excluder device is desired in angulated or short proximal necks.

Angioplasty↗
PubMed2005

The Bryan cervical disc system.

In May 2002, an Investigational Device Exemption (IDE) was granted by the US Food and Drug Administration (FDA) for clinical evaluation of the Bryan Cervical Disc System. The trial was designed to demonstrate equivalence with anterior discectomy and interbody fusion with plate fixation. Trial enrollment of over 500 patients was completed in 2004, and 2-year follow-up data are currently being collected and analyzed in preparation for submission to the FDA. This article describes the Bryan prosthesis, reviews several preclinical and clinical studies, and reports on the IDE study.

Animals↗
PubMed2005

Interim results of the United States investigational device study of the Ophtec capsular tension ring.

PURPOSE: To evaluate the safety and efficacy of the Ophtec capsular tension ring (CTR) in providing capsular support during and/or after cataract extraction in cases of a weak or partially broken ciliary zonule. DESIGN: Phase III multicenter, nonrandomized, investigational device study. PARTICIPANTS: Twelve investigators at 9 sites enrolled 224 subjects and placed 255 CTRs. METHODS: Capsular tension rings were placed in patients who were found to have a weakened or partially broken ciliary zonule comprising <34% of the circumference of the lens capsule. Two CTR models were evaluated, with noncompressed diameters of 12 mm and 13 mm. Patients were examined preoperatively, intraoperatively, and postoperatively at day 1 and months 1, 3, 6, and 12. MAIN OUTCOME MEASURES: Rate of successful stabilization of the capsular bag and intraocular lens (IOL) centration, complications, and adverse events. RESULTS: Interim results from this ongoing study indicate that immediately after surgery 98.8% of IOLs were centered and 1.2% of the IOLs implanted (3/251) were not centered. Subsequently, the prevalence of decentered IOLs was 1.7% (4/236) 3 months after surgery, 3.8% (8/211) 6 months after surgery, and 2.3% (4/172) 12 months after surgery. The primary complication was posterior capsular opacification, which is unlikely to be a complication of CTR insertion. Neodymium:yttrium-aluminum-garnet laser capsulotomies have been performed in 12.8% of eyes by 12 months (22/172). CONCLUSIONS: Ophtec CTR models 275 and 276 safely provided capsular support during and after cataract surgery in cases where the zonule was weak or partially broken.

Adult↗
PubMed2004

Resorption rate and biocompatibility characteristics of two polyester ventilation tubes in a guinea pig model.

OBJECTIVES: Determine the resorption rate and biocompatibility characteristics of 2 polyester ventilation tubes, and to determine whether soap and water exposure accelerates polyester tube degradation. STUDY DESIGN AND SETTING: 50/50 poly (D, L-lactide-co-glycolide; PLGA-50) and poly (L-lactide; PLA) polymers were placed into the tympanic membranes of Hartley pigmented guinea pigs. Integrity of the tubes was determined by weekly otoscopic examination. Biocompatibility was assessed by comparing auditory brainstem response (ABR) thresholds and by examining tympanic membrane changes following tube resorption. Shah minigrommet ventilation tubes were used as controls. In the second portion of this study, implanted PLGA-50 and PLA tubes were exposed weekly to a mixture of soap and water (1:5) until complete resorption was observed. Biocompatibility was assessed by periodic ABR testing and tympanic membrane examination. RESULTS: The PLA tubes remained in the tympanic membrane for a longer period (63.2 +/- 19.3 days) than the PLGA-50 (18.8 +/- 8.1 days). The tympanic membrane and resorbable tube interface demonstrated equivalent findings for auditory thresholds and tissue histopathology at the implant site compared to nonresorbable controls. The resorption behavior was not altered by exposure to soap and water. Tympanic membranes of all animals following tube degradation and soap water exposure were intact with minimal scarring and no signs of persistent foreign body response. The histological analysis showed that implantation of resorbable tubes was not accompanied by secondary infection with otorrhea through the tube, did not result in a permanent perforation or dislocation of the tube into the middle ear cavity, and was not followed by excess tympanosclerosis or localized or diffuse membrane atrophy. CONCLUSIONS AND SIGNIFICANCE: Resorbable polyester pressure equalization tubes demonstrate predictable resorption behavior and similar biocompatibility characteristics when compared with nonresorbable Shah minigrommet ventilation tubes. Exposure to soap water does not accelerate polyester tube degradation nor change the host tissue response during the indwelling period or after complete resorption. The data suggests that resorbable ventilation tubes are substantially equivalent to other FDA-approved tympanostomy devices with regard to safety and biocompatibility in the guinea pig model examined and may provide improved clinical performance by combining this approach with sustained release technology. EBM RATING: B-2.

Animals↗
PubMedDate not supplied

Disc arthroplasty: lessons learned from total joint arthroplasty.

BACKGROUND CONTEXT: With the rapid emergence of new disc arthroplasty designs and ongoing clinical trials, there is great anticipation among clinicians. Inevitably there will be challenges associated with adoption of this new technology. Potential lessons learned from the extensive experience with extremity arthroplasty may predict some of the perils and pitfalls associated with motion-preserving devices in spinal applications. PURPOSE: To review the extremity total joint literature for lessons that may be transferable to disc arthroplasty and anticipate predictable problems that will occur. STUDY DESIGN/SETTING: A literature review and conjectural analysis of key lessons learned from the experience of extremity total joint arthroplasty and anterior lumbar interbody fusion devices with subsequent application of these lessons to disc arthroplasty in the lumbar spine. METHODS: Limited data are available on disc arthroplasty. RESULTS: Particular areas of controversy and uncertainty exist. The ongoing US Food and Drug Administration Investigational Device Exemption clinical trials may provide additional insight into these questions. CONCLUSIONS: Complications will occur. These will be approach related, device related and patient-selection related. Studying the experience of extremity joint arthroplasty may accelerate the learning curve for lumbar disc arthroplasty.

Arthroplasty, Replacement↗
PubMed1996

Compatibility of a nonthoracotomy lead system with a biphasic implantable cardioverter-defibrillator. Cadence-Endotak 60-Series IDE investigators.

This prospective multicenter study was conducted under the Food and Drug Administration Investigational Device Exemption to evaluate the safety and efficacy of the combination of the Cadence implantable defibrillator (Ventritex, Inc.) and 60-series Endotak C leads (Cardiac Pacemakers, Inc.). Implantation was attempted in 148 patients with hemodynamically compromising ventricular tachycardia or fibrillation (VF), or with pace-terminable ventricular tachycardia. The system was successfully implanted in 97% of patients, with 96% of implants in a transvenous-lead-alone configuration. At implantation, the defibrillation threshold was 455 +/- 94 V (14 +/- 6 J) for lead-alone patients and 532 +/- 40 V (19 +/- 3 J) for those requiring a subcutaneous patch. VF conversion efficacy was reconfirmed in patients who underwent a 3-month chronic induction study. The system successfully detected all 763 induced arrhythmias and terminated 99.5% of them; after system modification, successful conversion was demonstrated in the 2 patients who initially had induced episodes requiring external defibrillation (1 lead revision; 1 reprogramming). All spontaneous episodes were terminated with an implantable-cardioverter defibrillator. Postshock VF redetection times were significantly shorter than initial detection times (4.5 +/- 1.8 seconds detection, 2.1 +/- 0.7 seconds redetection; p<0.0001). During an 8-month mean follow-up (range 1 to 31 months), 2 unwitnessed deaths were classified as sudden cardiac deaths, and 11 patients experienced a total of 12 complications, none of which was associated with the Cadence-Endotak combination.

Adult↗
PubMed2003

The initial experience with the ATS Medical mechanical cardiac valve prosthesis.

BACKGROUND: From May 1994 through October 2000, a total of 1,146 patients underwent valve replacement with the ATS Medical mechanical cardiac valve prosthesis under a study protocol approved by international ethics committees (non-United States participants) or under a United States Food and Drug Administration-approved Investigational Device Exemption study. The study took place at 19 domestic and three international centers. METHODS: As required by the Food and Drug Administration's Heart Valve Guidance Document, only isolated implants were included in the study (double-valve implants were excluded), with operative and follow-up data collected from each center. RESULTS: Aortic valve replacement (AVR) was conducted in 801 patients (309 with coronary bypass) and mitral valve replacement (MVR) in 345 patients (78 with coronary bypass). Overall operative (< or = 30 days post implant) mortality was 2.1% (17 AVR = 2.1%, 7 MVR = 2.0%), 7 of which (AVR = 4, MVR = 3) were valve related. In 2,086 patient-years (1,459 AVR patient-years, 627 MVR patient-years) of follow-up, there were an additional 50 patient deaths of these, 18 were valve related, 9 due to anticoagulant related bleeding, 5 sudden/unexplained, and 1 each after stroke, thrombosis, prosthetic valve endocarditis, and thromboembolism. Late (>30 days post implant) valve-related complications included: transient and chronic thromboembolism (27 AVR (linearized rate 1.85%/patient-year) and 20 MVR (3.19%/patient-year), of which 11/47 (0.53%/patient-year) had chronic deficits, thrombosis (1 AVR = 0.07%/patient-year and 4 MVR = 0.64%/patient-year), paravalvular leak (10 AVR = 0.69%/patient-year and 8 MVR = 1.28%/patient-year), anticoagulant related hemorrhage (34 AVR = 2.33%/patient-year and 8 MVR = 1.28%/patient-year), prosthetic valve endocarditis (3 AVR = 0.21%/patient-year and 2 MVR = 0.32%/patient-year), and structural valve failure or dysfunction (0%). Echocardiographic gradients were proportional to valve size and did not significantly change over the follow-up period. CONCLUSIONS: This study documented the ATS Medical mechanical cardiac valve prosthesis to be a valuable addition to the surgeon's armamentarium in the treatment of cardiac valvular disease.

Aged↗
PubMed2005

Enteryx implantation for GERD: expanded multicenter trial results and interim postapproval follow-up to 24 months.

BACKGROUND: Enteryx implantation in the esophagus is an alternative therapy for patients with proton pump inhibitor (PPI) dependent GERD. Although this treatment resulted in highly significant improvement at 6 and 12 months, longer follow-up is needed to more fully assess the durability of these positive effects. METHODS: An open-label, international clinical trial was conducted in 144 PPI-dependent patients with GERD with follow-up at 6 and 12 months. In addition, the durability and the safety of the treatment were assessed for 24 months in 64 patients enrolled in a postapproval study. The primary study outcome measure was usage of PPI. Secondary outcomes in the multicenter trial were GERD health-related quality of life (GERD-HRQL) symptom score and esophageal acid exposure. RESULTS: At 12 months, PPI use was reduced > or =50% in 84%: 95% confidence interval (CI) [76%, 90%] and was eliminated in 73%: 95% CI[64%, 81%] of evaluable patients (intent-to-treat analysis 78%: 95% CI[70%, 84%] and 68%: 95% CI[60%, 76%], respectively). A GERD-HRQL < or =11 was attained in 78%: 95% CI[69%, 85%] of evaluable patients. Esophageal acid exposure (total time pH <4) was reduced by 31%: 95% CI[17%, 43%]. At 24 months, a > or =50% or greater reduction in PPI use was achieved in 72%: 95% CI[59%, 82%] and PPI use was eliminated in 67%: 95% CI[54%, 78%] of patients. CONCLUSIONS: This investigation provides evidence for sustained effectiveness and safety of implantation of Enteryx in the esophagus in PPI-dependent patients with GERD.

Belgium↗
PubMed2003

Improvement of the reliability of ceramic hip joint implants.

The aim of this article is to present the optimization of a proof test procedure of ceramic hip joint ball heads. The proof test rejects defective samples in the production line before being implanted into human body. Thereby on every ceramic ball head a static load is applied, which is somewhat higher than the maximum physiological load. The magnitude of the applied load should not damage the samples which are free of flaws in the high stress area. The configuration of the proof test influences the stress distribution in the ball head, which should be similar to the physiological case. To determine the stress distribution, a non-linear finite element (FE) analysis was performed and the results were validated by measurements. With an iterative approach based on FE calculations the proof test configuration was optimized in such a way that the stress distribution in the ball head is similar to the stress distribution in vivo. In this study all ball heads showed very high fatigue resistance after being proof tested and fulfilled the requirements of the FDA (Food and Drug Administration, USA) described in the Guidance Document for the Preparation of Premarket Notifications for Ceramic Ball Hip System. The probability of a fracture of an implanted ceramic ball head can be decreased by the presented optimized proof test procedure. Latter can thus improve the reliability of ceramic hip joint ball heads. The study was supported by the KTI (Commission for Technology and Innovation, Switzerland).

Computer-Aided Design↗
PubMed1994

Implementation of ST-segment criteria in clinical monitoring devices. Implications of criteria from field trials and the federal regulatory process.

Manufacturers are challenged with providing ST-segment monitoring devices in a timely manner that meet the needs of clinicians and that satisfy the purview of the Federal Drug Administration (FDA) Office of Device Evaluation. The initial challenge is to explain the intended use for the product; are clinicians using the monitoring device to view measured ST-segment values or are they attempting to detect ischemic changes? A device that has only been tested by the manufacturer for its accuracy in detecting ST level changes may only be used for that purpose. A "field trial" of several months at clinical sites is typically conducted to confirm the accuracy of the St-segment measurement and to validate the device's "ease of use." If the monitoring device is intended for detecting ischemic changes, it must be clinically tested to demonstrate this capability. A "clinical trial" to detect ischemic changes could start to approach the scope and time one might expect for the clinical testing of a drug. Alarming for an ST-segment level change provides a dilemma for manufacturers. The FDA has questioned the rationale for providing ST alarms. The question comes from the position that ST-segment level changes have a low positive predictive accuracy for detecting "ischemia" (implications: clinical trial, etc.) and that many ST-segment level changes are not clinically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Device Approval↗
PubMed2001

Implantable middle ear hearing devices: Food and Drug Administration review process.

This article presents an overview of the role of the Food and Drug Administration in reviewing new devices and then explains this process in some detail as it applies to implantable middle ear hearing devices. The role of the Food and Drug Administration is to protect the patient and physician by reviewing devices for safety and effectiveness before they are made available for general use.

Device Approval↗