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PubMed2000

Evolving trends in interventional device use and outcomes: results from the National Cardiovascular Network Database.

BACKGROUND: Although multiple new coronary interventional devices have been approved for marketing in the United States, use of these technologies in general clinical practice and their associated outcomes have not been reported. METHODS AND RESULTS: Using the National Cardiovascular Network's Coronary Interventional Database, we examined temporal trends in the use and outcomes of coronary stents, lasers, directional atherectomy, and rotational atherectomy devices at 12 US hospitals between January 1994 and December 1997 (n = 76,904). Over this period, the percentage of cases involving coronary stents rose more than 12-fold (from 5.4% in 1994 to 69.0% in 1997). In contrast, use of atherectomy-type devices declined significantly. Device selection was strongly influenced by the patient's coronary anatomy and procedural indication, but less by age, sex, or race. Device use also varied significantly among individual centers (4-fold variation among sites in stent use and 6-fold variation in atherectomy use) even after adjusting for patient characteristics. Although overall mortality rates were unchanged during this 4-year period, procedural success rates have improved and complication rates have declined significantly. Lengths of postprocedure hospital stay also fell significantly for all patients undergoing coronary intervention in this time period. CONCLUSIONS: Percutaneous interventional strategies are rapidly changing with the explosive growth of coronary stent use and the decline in use of atherectomy devices. Patient outcomes, including complication rates and postprocedure lengths of stay, have also improved as the new interventional strategies have been refined in clinical practice.

Angioplasty, Balloon, Coronary↗
PubMed1991

Pacing for tachydysrhythmias.

Advances in cardiac electrophysiology have clarified some of the mechanisms of tachydysrhythmias and have characterized tachycardias that are amenable to pace termination. Tachydysrhythmias most likely to be terminated by pacing techniques tend to be slow, re-entrant tachycardias. Although single extrastimulation can be effective, its yield is relatively low. Delivery of multiple extrastimuli or burst pacing are more effective than single extrastimulation at the expense of a higher risk of tachycardia acceleration or transformation of the rhythm to fibrillation. The use of pacing for the termination of tachydysrhythmias has primarily been limited to the acute care setting, although permanently implantable antitachycardia pacemakers are being used in increasing numbers. While these devices have been approved by the Food and Drug Administration (FDA) for the treatment of supraventricular tachydysrhythmias, their use to treat ventricular tachydysrhythmias has produced mixed results and remains investigational. In some cases of sustained ventricular tachycardia, automatic cardioverter/defibrillators have been implanted along with antitachycardia pacemakers to provide high-energy shock back-up in case of tachycardia acceleration by the pacemaker. Soon, devices will be available which will combine, in a single unit, antitachycardia pacing and high-energy cardioversion/defibrillation.

Cardiac Pacing, Artificial↗
PubMed2003

Medical devices; reclassification of the knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis and the knee joint femorotibial (unicompartmental) metal/polymer porous-coated uncemented prosthesis. Final rule.

The Food and Drug Administration (FDA) is announcing that it has reclassified two fixed-bearing knee joint prostheses, the knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis, which is intended to be implanted to replace a knee joint, and the knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis, which is intended to be implanted to replace part of a knee joint. FDA has reclassified the devices from class III (premarket approval) into class II (special controls). The special control that will apply is a guidance document entitled "Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prostheses; Guidance for Industry and FDA." The agency is reclassifying these devices into class II because special controls, in addition to general controls, will provide reasonable assurance of the safety and effectiveness of the devices, and there is sufficient information to establish special controls. The agency is also announcing that it has issued an order in the form of a letter to the Orthopedic Surgical Manufacturers Association (OSMA) reclassifying the devices.

Device Approval↗
PubMed2005

Early-response biological dosimetry--recommended countermeasure enhancements for mass-casualty radiological incidents and terrorism.

The effective medical management of a suspected acute radiation overexposure incident necessitates recording dynamic medical data, measuring appropriate radiation bioassays, and estimating dose from dosimeters and radioactivity assessments in order to provide diagnostic information to the treating physician and a dose assessment for personnel radiation protection records. The accepted generic multiparameter and early-response approach includes measuring radioactivity and monitoring the exposed individual; observing and recording prodromal signs/symptoms and erythema; obtaining complete blood counts with white blood cell differential; sampling blood for the chromosome-aberration cytogenetic bioassay using the "gold standard" dicentric assay (translocation assay for long times after exposure) for dose assessment; bioassay sampling, if appropriate, to determine radioactivity contamination; and using other available dosimetry approaches. In the event of a radiological mass-casualty incident, current national resources need to be enhanced to provide suitable dose assessment and medical triage and diagnoses. This capability should be broadly based and include stockpiling reagents and devices; establishing deployable (i.e., hematology and biodosimetry) laboratories and reference (i.e., cytogenetic biodosimetry, radiation bioassay) laboratories; networking qualified reference radioactivity-counting bioassay laboratories, cytogenetic biodosimetry, and deployable hematology laboratories with the medical responder community and national radiation protection program; and researching efforts to identify novel radiation biomarkers and develop applied biological dosimetry assays monitored with clinical, deployable, and hand-held analytical systems. These research and applied science efforts should ultimately contribute towards approved, regulated biodosimetry devices or diagnostic tests integrated into a national radioprotection program.

Chromosome Aberrations↗
PubMed2004

The Zenith AAA endovascular graft.

The Zenith endovascular graft is the culmination of a worldwide collaboration of experts whose experience and developments were compiled, resulting in an endovascular prosthesis designed to treat infrarenal abdominal aortic aneurysms. The device is made of stainless steel, self-expanding Z-stents and polyester fabric. It has an uncovered stent with barbs (for fixation) that extend into the suprarenal aorta and is modular in design and allows for disparity in the length and diameter of the iliac arteries that are incorporated into the repair. A prospective study contrasting endovascular and open surgical patients was completed in 2002 and resulted in US Food and Drug Administration approval of the device for commercial sale within the USA. Although long-term data from the trial are still being evaluated, the worldwide experience with this device and its predicate devices has allowed for certain conclusions to be made with respect to performance expectations and aneurysm sac behavior. The periprocedural mortality in healthy patients with anatomy meeting the device instructions for use should be under 2%. The expected risk of endoleak (mostly Type II) was 7.4% at 12 months and 5.4% at 24 months. Migration (based on the reporting standards for endovascular aneurysm repair recommended by the vascular surgical societies, published in the Journal of Vascular Surgery in 2001) was not seen in any patients over 12 months. The majority of the aneurysms shrink at 1 and 2 years, and any patient exhibiting aneurysm growth had a detectable cause and required treatment. Coupled with European and Australian data, including several device explants, the device integrity issues are limited to barb separation (which has about a 2% incidence and appears incidental in the US trial) and suprarenal stent detachment (six cases detected worldwide). In order to address the latter problem, a design alteration was implemented with a double suture attachment, significantly increasing the tensile strength of the device. No separations have been noted since the change instituted at the conclusion of the US trial.

Angioplasty↗
PubMed2004

Stent graft treatment for abdominal aortic aneurysm repair: recent developments in therapy.

PURPOSE OF REVIEW: Minimally invasive endovascular techniques for the treatment of abdominal aortic aneurysms have significantly reduced the morbidity of these procedures compared with standard surgical repair. In addition, patients with extensive comorbid medical illnesses in whom standard operative repair is contraindicated may be successfully treated using endovascular means. RECENT FINDINGS: Recently, several important developments have significantly advanced this area of treatment. The Food and Drug Administration has approved four endovascular stent grafts for the treatment of abdominal aortic aneurysms: the Medtronic AneuRx, the W.L. Gore Excluder, the Cook Zenith, and the Guidant Ancure. The Zenith received approval for marketing in 2003 and has gained relatively wide use, in part because of its ability to treat aneurysms with relatively large-diameter implantations zones. Also in 2003, Guidant Corporation withdrew the Ancure graft from marketing and distribution. The withdrawal was influenced by difficulties encountered using the graft's delivery system and improper reporting to the Food and Drug Administration. Enrollment has also been recently completed for the phase II Food and Drug Administration trials of the Medtronic Talent graft and the Cordis Fortron graft. These devices have been approved for use in the European Union and are awaiting Food and Drug Administration panel meeting in the United States. Several significant advances have also occurred recently in stent graft research and development. Of particular significance has been the initiation of the phase I trial of the Trivascular Enovus graft. Deployment of the Trivascular graft may be accomplished through a delivery system that is considerably reduced in profile. The potential for percutaneous application of the graft may be available in the future. In selecting the specific stent graft to be used for endovascular abdominal aortic aneurysm repair, the specific graft characteristics must be considered, particularly with regard to the individual patient's anatomic and physiologic characteristics. Comparative analysis of the several of the various stent grafts has been performed. Results have varied with regard to the need for secondary interventions, aneurysm sac size reduction, and the occurrence of continued perfusion of the aneurysm sac. In addition, the indications for use of endovascular grafts compared with standard open surgery have not yet been fully defined. SUMMARY: This article describes the general principles of use for endovascular devices for the repair of abdominal aortic aneurysms. It details the features and results for the devices in current use, and highlights the recent developments in stent graft treatment of abdominal aortic aneurysms.

Aortic Aneurysm, Abdominal↗
PubMed1978

Mechanical circulatory support: evolving perspectives.

Mechanical circulatory support of the failing circulation is an emerging discipline. Prototype circulatory support services have been established in a few institutions but are spreading15. Intra-aortic balloon pumping, developmental only a decade ago, is now widespread. Pneumatically-actuated intra and extracorporeal left ventricular assist devices, federally-approved for clinical trials only 2 yrs ago, show encouraging early results. Efforts in West Germany, Austria, Switzerland, Russia and Japan are underway and a spirit of cooperation exists. There is a need to clarify and quantitate indications and timing for deployment, prior to the onset of multiple organ failure. Electrically and nuclear-activated LVAD's16--18 are being developed. Clarification of projected patient populations are needed and the role of the right heart in left ventricular assist device function requires further investigation. There is a need to define a reasonable clinical role for the much discussed and rather elusive total artificial heart. Many problems remain with actuation, energy conversion, percutaneous leads, compliance devices and biomaterials. The challenges are many and welcomed.

Assisted Circulation↗
PubMed2006

The Thoratec Implantable Ventricular Assist Device (IVAD): initial clinical experience.

BACKGROUND: The Thoratec Implantable Ventricular Assist Device (IVAD) is the only FDA-approved intracorporeal biventricular cardiac assist device. It is a titanium-coated version of its predecessor, the Paracorporeal Ventricular Assist Device (PVAD). The blood pump is compatible with the portable TLC-II driver, making home discharge feasible. METHODS: Nine consecutive patients were implanted with the IVAD from June 2005 through March 2006. The indications for support were acute heart failure in 6 cases and chronic heart failure in 3 cases. All patients were managed with maximal medical therapies including intravenous inotropic drugs prior to implant. RESULTS: All patients survived the surgical implant. Six patients were considered successful: 3 patients discharged to home and subsequently received transplantation, 2 are awaiting transplantation (1 at home and 1 in-house), and 1 patient was successfully explanted. Three patients expired postoperatively because of multiple organ system failure (2 patients) and pulmonary hemorrhage (1 patient). There were no device malfunctions. There was 1 localized driveline site infection and 1 thromboembolic event with partial visual loss. CONCLUSIONS: The IVAD is a unique device capable of providing uni- or bi-ventricular support for either acute or chronic heart failure conditions. Its versatility permits bridge to transplant or recovery options. Home discharge is feasible.

Adult↗
PubMedDate not supplied

Cochlear implant candidacy and surgical considerations.

Numerous changes continue to occur in regard to cochlear implant candidacy. In general, these have been accompanied by concomitant and satisfactory changes in surgical techniques. Together, this has advanced the utility and safety of cochlear implantation. Most devices are now approved for use in patients with severe to profound rather the prior requirement of a bilateral profound loss. In addition, studies have begun utilizing short electrode arrays for shallow insertion in patients with considerable low frequency residual hearing. This technique will allow the recipient to continue to use acoustically amplified hearing for the low frequencies simultaneously with a cochlear implant for the high frequencies. New hardware, such as the behind-the-ear speech processors, require modification of existing implant surgery. Similarly, the new perimodiolar electrodes require special insertion techniques. Bilateral implantation clearly requires modification of the surgical techniques used for unilateral implantation. The surgery remains mostly the same, but takes almost twice as long, and requires some modification since at a certain point, when the first device is in contact with the body, the monopolar cautery may no longer be used. Research has already begun on the development of the totally implantable cochlear implant (TICI). This will clearly require a modification of the surgical technique currently used for the present semi-implantable devices. In addition to surgically burying the components of the present cochlear implant, we will also have to develop techniques for implanting a rechargeable power supply and a microphone for the TICI. The latter will be a challenge, since it must be placed where it is capable of great sensitivity, yet not exposed to interference or the risk of extrusion. The advances in design of, and indications for, cochlear implants have been matched by improvements in surgical techniques and decrease in complications. The resulting improvements in safety and efficacy have further encouraged the use of these devices. We anticipate further changes in the foreseeable future, for which there will likely be surgical problems to solve.

Age Factors↗
PubMed1985

Guidance for the emergency use of unapproved medical devices; availability--FDA. Notice.

The Food and Drug Administration (FDA) is announcing guidance, developed by FDA's Center for Devices and Radiological Health (CDRH), with respect to those emergency situations in which the agency would not object to a physician's using a potentially life-saving medical device for a use for which the device ordinarily is required to have, but does not have, an approved application for premarket approval or an investigational device exemption. The guidance is contained in a document entitled "guidance for the Emergency Use of Unapproved Medical Devices."

Emergencies↗
PubMed1998

The Clarion Multi-Strategy Cochlear Implant--surgical technique, complications, and results: a single institutional experience.

OBJECTIVE: This study aimed to review a single institution's experience with Clarion Multi-Strategy Cochlear Implant with respect to surgical technique, surgical complications, and rehabilitative outcome. STUDY DESIGN: This study was a review of patients implanted with the Clarion Multi-Strategy Cochlear Implant. SETTING: The setting was a tertiary referral center with care delivered in the inpatient and outpatient environment. PATIENTS: The first 37 patients were implanted under an Investigational Device Exemption as part of the Food and Drug Administration (FDA) clinical trial of the Clarion implant. Subsequent patients were implanted after the device received FDA approval. Patients met the following criteria for implantation: 18 years of age or older, psychological and emotional stability, profound postlingual deafness without evidence of middle ear disease, one cochlea at least partially patent, and marginal or no benefit from conventional hearing aids. INTERVENTION: Patients received implantation with the Clarion Multi-Strategy Cochlear Implant. MAIN OUTCOME MEASURES: Measured were presence or absence of surgical complications and auditory performance with open- and closed-set word and sentence recognition testing. RESULTS: A total of 47 patients have been implanted. Three patients have suffered complications: two cases of delayed-onset facial palsy both resolved with steroid therapy and one case of internal cochlear stimulator migration required refixation. Significant improvement in speech understanding has been seen in the majority of patients who were implanted within the first 6 months of device use. Specifically, at 6 months, scores on CID (Central Institute for the Deaf) sentences (implant alone) improved from a preoperative mean of 9% to a mean of 72%, and scores on the NU-6 (Northwestern University) monosyllabic word test increased from a preoperative mean of 3% (range, 0-20%) to a mean of 32% (range, 0-70%). More than two thirds (68%) of the adults were able to understand at least 50% of sentences over the telephone, and half were able to understand at least 75% of the sentence material. CONCLUSIONS: The authors' institutional experience with the Clarion Multi-Strategy Cochlear Implant shows minimal surgical morbidity and significant improvement on all open-set test measures of sentence and word recognition.

Adult↗
PubMed2005

Randomized evaluation of the TriActiv balloon-protection flush and extraction system for the treatment of saphenous vein graft disease.

OBJECTIVES: The Protection During Saphenous Vein Graft Intervention to Prevent Distal Embolization (PRIDE) study compared outcomes with the TriActiv System (Kensey Nash Corp., Exton, Pennsylvania), a balloon-protection flush and extraction device, with an embolic protection group during treatment of saphenous venous grafts (SVGs). BACKGROUND: Treatment of SVGs with embolic protection reduces adverse cardiac events. METHODS: We conducted a prospective trial randomizing 631 patients with coronary ischemia and lesions in SVGs to embolic protection with the TriActiv System or control group (Guardwire System [Medtronic AVE, Santa Rosa, California] or Filterwire EX [Boston Scientific Corp., Maple Grove, Minnesota]). RESULTS: The incidence of major adverse cardiac events at 30 days was 11.2% for the TriActiv group and 10.1% for the control group (relative risk = 1.1%; 95% confidence interval 0.67 to 1.76; p = 0.65; p = 0.02 for non-inferiority). Safety and efficacy end points were similar between groups except that patients randomized to the TriActiv System had more hemorrhagic complications (10.9% vs. 5.4%; p = 0.01). CONCLUSIONS: The TriActiv System was not inferior to approved embolic protection devices for the treatment of diseased SVGs.

Adult↗
PubMedDate not supplied

The development of in vitro biocompatibility tests for the evaluation of intraocular biomaterials.

Recent developments in ocular implant technology require the in vitro evaluation of ocular compatibility in early stage development programs. This requires an understanding and appreciation of the biological interactions which occur in the ocular environment and their relevance with respect to the clinical complications associated with surgical implantation of devices. This paper describes the development of a series of clinically reflective in vitro assays for assessing the potential ocular compatibility of novel intraocular lens materials. Staphylococcus epidermidis attachment, fibrinogen adsorption, mouse embryo fibroblast 3T3 adhesion and proliferation, primary rabbit lens cell adhesion, human peripheral blood macrophage adhesion and granulocyte activation tests were employed to evaluate two widely used intraocular biomaterials poly(methyl methacrylate) (PMMA) and silicone, and a novel biomimetic phosphorylcholine-based coating (PC). The performance of these materials in the in vitro assays was compared to their ability to reduce postoperative inflammation in vivo in a rabbit model. The results demonstrated that the in vitro assays described here are predictive of in vivo ocular compatibility. These assays offer a more relevant means of assessing the ocular compatibility of biomaterials than those presently required by the authorities for regulatory approval of medical devices and implants.

Journal Article↗
PubMed2003

Evaluation of a novel 2 mm internal diameter stainless steel saphenous vein to coronary artery connector: laboratory studies of on-pump and off-pump revascularization.

OBJECTIVE: A second generation, 'easy-load', 2 mm internal diameter (ID), stainless steel, distal anastomotic device has been developed, and design improvements facilitate rapid connector loading with minimal magnification. The reduced size should allow application to most distal coronary vessels currently grafted. This technology may be useful in off-pump and minimally invasive surgical approaches to coronary revascularization. METHODS: Two distinct models were used to evaluate the distal connector. In the first model, a single saphenous vein graft (SVG)-to-LAD procedure (n=18) was used to evaluate long-term patency of the 2 mm ID, stainless steel, distal connector in a chronic canine model. Cardiopulmonary bypass was initiated through an anterolateral thoracotomy. Aortosaphenous vein anastomoses were created using suture. In the second model, an acute off-pump feasibility study of SVG-to-LAD bypass fashioned with both proximal and distal connectors (n=15) was conducted. Aortosaphenous vein anastomoses were performed using a FDA approved vascular connector. Device loading and deployment times, graft blood flow following native LAD ligation, and device-related complications were compared. In the chronic model, the grafts were examined by angiography and gross and microscopic examination at animal sacrifice. RESULTS: All 33 animals survived the procedures. All grafts were widely patent after a minimum 30 (n=8), 90 (n=5), and 180 days (n=5) in the chronic model. Distal graft loading and deployment times, graft blood flow rates, and device-related complications were similar in both procedures. In the off-pump feasibility study, total grafting time including loading and deployment was 10:54+/-2:54 min. CONCLUSIONS: Sutureless SVG-to-coronary artery bypass is feasible, rapid, and reproducible with on- and off-pump surgical techniques using a 2 mm ID, stainless steel, distal connector. In this model, early graft patency was 100% with either procedure, and grafts performed on-pump were widely patent at 30, 90, and 180 days. Few device-related complications occurred, each easily managed without compromising graft integrity, and the incidence of events was similar whether on- or off-pump techniques were employed. This or similar technologies may become an important addition to the management of coronary artery disease, particularly in off-pump or minimally invasive approaches.

Anastomosis, Surgical↗
PubMed1997

Semi-implantable middle ear electromagnetic hearing device for sensorineural hearing loss.

A semi-implantable middle ear electromagnetic hearing device (SIMEHD) is proposed for limited clinical trial in adult patients to evaluate the implantable hearing device for moderate to severe sensorineural hearing loss. Food and Drug Administration (FDA) investigational device exemption (IDE) approval has been granted (May 1996) for clinical trials. The implant unit has been evaluated acutely and chronically in animals (cats) with excellent results. Five cats undergoing chronic implantation were allowed to survive an average of 9.6 months, showing that the SIMEHD is biocompatible, functional and without untoward complications. All implant units recovered from the cats were functional, except for wire breakage of the internal antenna. A new antenna was redesigned for human implantation. The SIMEHD system consists of an external and internal unit. The external unit consists of a microphone, audio amplifier, modulator, radio frequency (RF) amplifier, antenna and battery. The internal unit is composed of a receiving antenna, hybrid electronic circuit, air core driving coil, and a target magnet cemented to the incus. All materials in contact with the body are biocompatible and expected to survive indefinitely. The implant unit is miniaturized and manufactured with existing fabrication technology by our industrial collaborator, Wilson Greatbatch, Ltd. The specific aims and major tasks of the proposed research are: a) to evaluate reliability, safety and efficacy of the SIMEHD system in a selected group of patients diagnosed with sensorineural hearing loss, due mainly to presbycusis or aging of the inner ear; and b) to obtain objective and subjective evaluation of audiologic and psychoacoustic performance as compared to the acoustic hearing aid. This paper describes the design, illustrates the actual device (newest prototype) and details the technique for surgical implantation in the attic and mastoid antrum in humans.

Adult↗
PubMed1998

Medical devices; investigational device exemptions--FDA. Final rule.

The Food and Drug Administration (FDA) is amending the Investigational Device Exemptions (IDE) regulation. The regulatory changes are intended to reflect amendments to the Federal Food, Drug, and Cosmetic Act (the act) by the FDA Modernization Act of 1997 (FDAMA). These amendments provide that the sponsor of an IDE may modify the device and/or clinical protocol, without approval of a new application or supplemental application, if the modifications meet certain criteria and if notice is provided to FDA within 5 days of making the change. The rule also defines the credible information to be used by sponsors to determine if the criteria are met.

Clinical Protocols↗
PubMed1998

Medical devices; investigational device exemptions--FDA. Proposed rule.

The Food and Drug Administration (FDA) is proposing to amend the Investigational Device Exemptions (IDE) regulation. The proposed regulatory changes are intended to reflect amendments to the Federal Food, Drug, and Cosmetic Act (the act) by the FDA Modernization Act of 1997 (FDAMA). These amendments provide that the sponsor of an IDE may modify the device and/or clinical protocol, without approval of a new application or supplemental application, if the modifications meet certain criteria and if notice is provided to FDA within 5 days of making the change. The proposed rule also defines the credible information to be used by sponsors to determine if the criteria are met.

Clinical Protocols↗
PubMed2002

Mechanical thrombectomy devices for the treatment of peripheral arterial occlusions.

The changing landscape of thrombolytic drugs used for treating peripheral occlusive disease has spurred increasing use of mechanical thrombectomy devices (MTDs). These devices comprise a variety of tools intended to remove, fragment, or disperse thrombus in veins, arteries, or bypass grafts. Although most devices are U.S. Food and Drug Administration approved for use in occluded hemodialysis access grafts, only one, the AngioJet device, is currently approved for use in peripheral arterial applications. Nevertheless, most devices have been used for this off-label application, and clinical centers have published their results. This article reviews the distinguishing features of current mechanical thrombectomy devices, as well as the currently available literature reporting on their use in peripheral arterial occlusions.

Arterial Occlusive Diseases↗