A novel endovascular clip system for the treatment of intracranial aneurysms: technology, concept, and initial experimental results. Laboratory investigation.

OBJECT: The authors describe a novel device for the endovascular treatment of intracranial aneurysms, the endovascular clip system (eCLIPs). Descriptions of the device and its delivery system as well as the results of flow model tests and the treatment of experimental aneurysms are provided. METHODS: The eCLIPs comprises a flexible hybrid implantable device (an anchor and a covered leaf) and a balloon catheter delivery system, designed to be positioned and activated in the parent vessel in such a way that the covered portion will abut the aneurysm neck. The eCLIPs was subjected to testing in glass, elastomeric, and cadaveric flow models to determine its navigability, orientation, and activation compared with commercially available stents. In a second experiment, 8 carotid artery sidewall aneurysms in swine were treated using eCLIPs. The degree of occlusion was observed on angiography immediately following and 30 days after device activation, and a histological analysis was performed at 30 days. RESULTS: The device could navigate tortuous glass models and human cadaveric vessels. Compared with commercially available stents, the eCLIPs performed well. It could be navigated, oriented, and activated easily and reliably. With regard to the 8 porcine experimental aneurysms, immediate postactivation angiograms confirmed complete occlusion of 4 lesions and near occlusion of the other 4. Angiographic follow-up at 30 days postactivation showed occlusion of all 8 aneurysms and patency of all parent vessels. Histopathological analysis revealed aneurysm healing, with smooth-muscle cells growing across the lesion neck to allow reendothelialization. CONCLUSIONS: Aneurysm occlusion with a single extrasaccular endovascular device has potential advantages. The authors believe that eCLIPs may prove to be a useful tool in the endovascular treatment of cerebral aneurysms. The system should reduce risks associated with coiling, procedure time, costs, and radiation exposure. The device satisfactorily occluded 8 experimental sidewall aneurysms. The observed healing pattern is similar to that seen after microsurgical clipping.

Physiological remodeling of bifurcation aneurysms: preclinical results of the eCLIPs device.

OBJECTIVE Intracranial bifurcation aneurysms are complex lesions for which current therapy, including simple coiling, balloon- or stent-assisted coiling, coil retention, or intrasaccular devices, is inadequate. Thromboembolic complications due to a large burden of intraluminal metal, impedance of access to side branches, and a high recurrence rate, due largely to the unmitigated high-pressure flow into the aneurysm (water hammer effect), are among the limitations imposed by current therapy. The authors describe herein a novel device, eCLIPs, and its use in a preclinical laboratory study that suggests the device's design and functional features may overcome many of these limitations. METHODS A preclinical model of wide-necked bifurcation aneurysms in rabbits was used to assess functional features and efficacy of aneurysm occlusion by the eCLIPs device. RESULTS The eCLIPs device, in bridging the aneurysm neck, allows coil retention, disrupts flow away from the aneurysm, leaves the main vessel and side branches unencumbered by intraluminal metal, and serves as a platform for endothelial growth across the neck, excluding the aneurysm from the circulation. CONCLUSIONS The eCLIPs device permits physiological remodeling of the bifurcation.

Percutaneous aortic valve implantation retrograde from the femoral artery.

BACKGROUND: Percutaneous aortic valve implantation by an antegrade transvenous approach has been described but is problematic. Retrograde prosthetic aortic valve implantation via the femoral artery has potential advantages. Percutaneous prosthetic aortic valve implantation via the femoral arterial approach is described and the initial experience reported. METHODS AND RESULTS: The valve prosthesis is constructed from a stainless steel stent with an attached trileaflet equine pericardial valve and a fabric cuff. After routine aortic balloon valvuloplasty, a 22F or 24F sheath is advanced from the femoral artery to the aorta. A steerable, deflectable catheter facilitates manipulation of the prosthesis around the aortic arch and through the stenotic valve. Rapid ventricular pacing is used to reduce cardiac output while the delivery balloon is inflated to deploy the prosthesis within the annulus. Percutaneous aortic prosthetic valve implantation was attempted in 18 patients (aged 81+/-6 years) in whom surgical risk was deemed excessive because of comorbidities. Iliac arterial injury, seen in the first 2 patients, did not recur after improvement in screening and access site management. Implantation was successful in 14 patients. After successful implantation, the aortic valve area increased from 0.6+/-0.2 to 1.6+/-0.4 cm2. There were no intraprocedural deaths. At follow-up of 75+/-55 days, 16 patients (89%) remained alive. CONCLUSIONS: This initial experience suggests that percutaneous transarterial aortic valve implantation is feasible in selected high-risk patients with satisfactory short-term outcomes.

Role of preliminary registry data in development of a clinical trial for an innovative device: a small but integral piece of a health policy initiative.

Establishing a national health policy at a macro level involves the integration of a series of health initiatives across a spectrum of activities, including clinical care. Evaluation of the safety and efficacy of a new medical device ultimately evolves to testing in humans. The pathway to a formal prospective clinical trial includes a stepwise appreciation of pre-clinical data and detailed analysis of data obtained from preliminary registries, where information about appropriate patient selection and use of the device is obtained. Evaluation of procedural and follow-up efficacy and safety data in a preliminary series of cases, chosen to simulate published data, allows the design and conduct of clinical trials that are required to verify preliminary observations, closing the loop on one aspect of modifying health policy decisions.

Percutaneous aortic valve implantation: a case report.

The present case demonstrates the percutaneous implantation of a bioprosthetic valve in a patient with severe aortic stenosis. An 85-year-old man with significant comorbidities was determined to be at unacceptable risk with traditional surgical valve replacement. Percutaneous aortic valve implantation was performed, was successful and uncomplicated, with significant clinical and hemodynamic improvement. Currently, this procedure is an option only for symptomatic patients who are not appropriate candidates for surgical valve replacement.

A training paradigm to enhance performance and safe use of an innovative neuroendovascular device.

Training has been important to facilitate the safe use of new devices designed to repair vascular structures. This paper outlines the generic elements of a training program for vascular devices and uses as an example the actual training requirements for a novel device developed for the treatment of bifurcation intracranial aneurysms. Critical elements of the program include awareness of the clinical problem, technical features of device, case selection, and use of a simulator. Formal proctoring, evaluation of the training, and recording the clinical outcomes complement these elements. Interventional physicians should embrace the merits of a training module to improve the user experience, and vendors, physicians, and patients alike should be aligned in the goal of device training to improve its success rate and minimize complications of the procedure.

The profile of cardiac patients with renal artery stenosis.

OBJECTIVES: We examined the prevalence and severity of renal artery stenosis (RAS) in patients undergoing cardiac catheterization who were deemed at risk for RAS based on clinical or laboratory criteria for study entry, but who had not previously been suspected of having RAS. BACKGROUND: The diagnosis of atherosclerotic RAS remains problematic because its clinical manifestations are nonspecific. METHODS: Consecutive patients undergoing non-emergent cardiac catheterization at a single institution during a 12-month period were evaluated using standardized clinical, laboratory, and angiographic criteria. Patients exhibiting at least one of four predefined selection criteria (severe hypertension, unexplained renal dysfunction, acute pulmonary edema with hypertension, or severe atherosclerosis) were prospectively registered and underwent coincident diagnostic renal angiography. RESULTS: Renal angiography was performed in 851 patients and was diagnostic in 837. Angiographically evident renal atherosclerosis was present in 39% of the population, with RAS > or =50% in 120 (14.3%) and severe stenosis (> or =70%) in 61 (7.3%). Severe stenosis was present in 48 (7%) patients with severe atherosclerosis, 38 (16%) with renal dysfunction, 25 (9%) with hypertension, and 2 (22%) with acute pulmonary edema with hypertension. The prevalence was higher in those exhibiting multiple selection criteria. In a multivariate model, severe RAS was associated with age, female gender, reduced creatinine clearance, increased systolic blood pressure, and peripheral or carotid artery disease. CONCLUSIONS: In a population at risk of, but not previously suspected of having RAS, severe RAS is associated with simple and readily determined clinical and laboratory patient characteristics. These data facilitate focused application of diagnostic renal angiography.

Six-month angiographic and 12-month clinical follow-up of MultiLink long (25 to 35 mm) stents for long coronary narrowings in patients with angina pectoris.

There are limited prospective angiographic data on stent deployment for long coronary lesions. This multicenter prospective study enrolled 120 patients with a single de novo stenosis >20 mm in length, in a native vessel > or =3 mm diameter, suitable for a MultiLink stent 25 to 35 mm in length with additional stent deployment if required. Quantitative angiography before and immediately after stenting and at 6-month follow-up assessed restenosis for the complete lesion and for 5-mm segments of the stented and adjacent nonstented vessel. By 1 year, myocardial infarction had occurred in 3% and target vessel repeat revascularization in 12% of patients. The mean stented length (35.8 +/- 14.6 mm) closely matched mean lesion length (30.1 +/- 13.5 mm). Restenosis to > or =50% diameter loss occurred in 32% of patients, but to > or =70% in only 8%. Of the 147 segments (5 mm in length) with baseline stenosis <25%, only 3 patients (2%) developed restenosis of > or =50%, and only in 1 of these was it > or =70%. Stenting of long narrowings is associated with good clinical outcome and a low rate of severe restenosis. Mildly diseased segments of long lesions covered by a stent rarely became severely narrowed and had negligible influence on the overall restenosis rate. These data support a strategy of full lesion coverage by stent deployment.

Abbreviated infusion of eptifibatide after successful coronary intervention The BRIEF-PCI (Brief Infusion of Eptifibatide Following Percutaneous Coronary Intervention) randomized trial.

OBJECTIVES: The purpose of this study was to assess whether the early discontinuation of eptifibatide infusion in nonemergent percutaneous coronary intervention (PCI) is associated with a higher frequency of periprocedural ischemic myonecrosis. BACKGROUND: The recommended regimen for eptifibatide is a double bolus followed by an infusion for 18 h. It is not known whether the infusion can be shortened if the PCI is uncomplicated. METHODS: We enrolled 624 patients with stable angina, acute coronary syndrome, or recent ST-segment elevation myocardial infarction (>48 h) who underwent successful coronary stenting and received eptifibatide. Patients were randomly assigned to receive either an 18-h infusion or an abbreviated infusion of <2 h. The primary end point was the incidence of periprocedural myonecrosis defined as troponin-I elevation >0.26 microg/l. Secondary end points included death, myocardial infarction, urgent target vessel revascularization at 30 days, and in-hospital major bleeding using the REPLACE-2 (Randomized Evaluation in PCI Linking Angiomax to Reduced Clinical Events) trial criteria. RESULTS: The incidence of periprocedural myonecrosis was 30.1% in the <2-h group versus 28.3% in the 18-h group (mean difference: 1.8%; upper bound of 95% confidence interval: 7.8%; p < 0.012 for noninferiority). The 30-day incidence of myocardial infarction, death, and target vessel revascularization was similar in both groups (p = NS). Major bleeding was less frequent in the <2-h group (1.0% vs. 4.2%, p = 0.02). CONCLUSIONS: After uncomplicated PCI, eptifibatide infusion can be abbreviated safely to <2 h. It is not inferior to the standard 18-h infusion in preventing ischemic outcome, and it may be associated with less major bleeding. (Brief Infusion of Eptifibatide Following Percutaneous Coronary Intervention [BRIEF PCI]; NCT00111566).

Procedural efficacy and complications of X-Sizer thrombectomy in de novo and stented lesions.

Angiographic thrombus is associated with poorer procedural and clinical outcomes. We report our experience with the X-Sizer thrombectomy device (EndiCOR Medical) from March 2001 to December 2002. Indications for use in 44 patients (33 male; mean age, 60) included myocardial infarction (27), unstable angina (6), periprocedural thrombosis (2), acute (< 24 hr) stent thrombosis (1), and subacute (> 24 hr) stent thrombosis (8). Three cases involved vein grafts. Deployment was successful in 42/44. Difficulty traversing the stent occurred in 5/9 cases of in-stent thrombosis. Median TIMI flow increased from 1 to 2 (P = 0.01) postthrombectomy. Median final TIMI flow was 3. Complications included dissection (1), perforation, device jam on stent (1), disruption of a covered stent (1), distal macro-embolization (4), and transient no-reflow (5). The X-Sizer thrombectomy device improves TIMI flow but does not always prevent distal embolization. Care is needed when treating in-stent thrombosis.