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Biomedical subjects

Barry T Katzen

Publications and source records attributed to Barry T Katzen.

At least 19 recordsLinked to original sources
PubMed2006

Carotid stenting with distal protection in high surgical risk patients: the BEACH trial 30 day results.

BACKGROUND: The BEACH trial evaluated the outcomes of carotid artery stent placement with distal emboli protection, using the Carotid Wallstent and the FilterWire EX/EZ(TM), in patients at high surgical risk for carotid endarterectomy (CEA). METHODS: We enrolled 747 patients at high surgical risk for CEA due to prespecified anatomical criteria and/or medical comorbidities. The trial included both symptomatic (>50% carotid artery stenosis) as well as asymptomatic (>80% carotid artery stenosis) high surgical risk patients. Three groups of patients were included in the trial. The Roll-in (R) group (n = 189/747, [25%]) included up to nine patients per site for familiarization of the device and protocol; the Pivotal (P) group (n = 480/747, [65%]) was intended for presentation to the FDA for consideration of device approval; and a Bilateral (B) registry group (n = 78/747, [10%]) was included because of the need to treat patients with bilateral carotid artery disease. In the 480 Pivotal patients, anatomic criteria represented the most frequent high-risk surgical category for enrollment (58.8%), followed by prior CEA (34.2%), multivessel (>or=2) coronary artery disease (21.7%), and contralateral carotid occlusion (18.1%). RESULTS: The technical success rate for stent deployment and FilterWire EX/EZ deployment and retrieval was 98.2%. The mean postprocedure angiographic diameter stenosis in the Pivotal group was reduced to 10.8%, while the overall procedure success rate (<50% residual diameter stenosis) after stent deployment was 98%. The 30 day composite major adverse event (MAE) rate for the entire cohort of 747 patients (i.e. inclusive of all 3 groups) was 5.8% (all death = 1.5%, all stroke = 4.4%, and all myocardial infarction (MI) = 1.0%). In subgroup analysis, there was no significant difference in the MAE rate between the three groups (P = 5.8%, R = 6.9%, B = 2.6%, P = 0.42). CONCLUSION: The similarity in periprocedural event rates for the Pivotal and Roll-in groups suggests a flat learning curve for experienced operators using this carotid stent system. The similarity in event rates for the Bilateral group, when compared with the Roll-in and Pivotal groups, suggests that staged sequential treatment of bilateral stenoses may be performed at the same risk as for unilateral lesions. The 30-day safety of this stent and distal emboli protection system is encouraging and compares favorably with other carotid stent trials in high surgical risk patients.

Aged↗
PubMed2005

Past, present, and future endograft devices.

Since the original descriptions of endovascular grafts for treatment of aneurysms, a number of devices and approaches have been developed. The following is a discussion summarizing the number of devices which have been developed and used in patients, as well as chosen the directions of this technology. The diversity of approach from an engineering and materials point of view speaks of the fact that opportunity exists for continued development in the future.

Aortic Aneurysm, Abdominal↗
PubMed2005

Bivalirudin as an anticoagulation agent: safety and efficacy in peripheral interventions.

PURPOSE: Traditionally, unfractionated heparin is used to prevent thrombotic complications in peripheral interventions. The purpose of this study is to evaluate the use of bivalirudin as the anticoagulant agent for peripheral interventions. MATERIALS AND METHODS: A retrospective analysis of 108 patients who underwent 110 peripheral interventions between January 2002 and January 2004 and received bivalirudin as the sole anticoagulation agent was conducted at Baptist Cardiac and Vascular Institute. Interventions were performed in the following areas: iliac, femoropopliteal, and distal (n = 55), carotid (n = 31), vertebral (n = 1), renal (n = 14), aorta (n = 7), and subclavian (n = 2). The following procedural and clinical endpoints were examined: death, requirement of urgent surgery or surgery during the same admission, urgent percutaneous revascularization in the same treated vessel, thrombotic or embolic events, bleeding events, and groin complications. RESULTS: A total of 266 lesions were dilated in 185 arteries. There were no procedural mortalities, procedural success was 99.1%, and the complication rate was 3.6%. There was one embolic stroke (0.9%), one thrombosis (0.9%), and two groin hematomas (1.8%). No patient required urgent surgery or reintervention in the same treated vessel. No complications were noted at 7 days after the procedure. There were two interventions by postprocedure day 30: toe amputation and groin debridement. CONCLUSION: Bivalirudin is a safe alternative to unfractionated heparin as the anticoagulation agent in peripheral interventions. This study shows that the complication profile is comparable to other bivalirudin studies. Bivalirudin is effective, easy to use, and is associated with few bleeding complications.

Aged↗
PubMed2005

Feasibility trial of carotid stenting with and without an embolus protection device.

PURPOSE: To evaluate the feasibility of stenting and cerebral protection in patients with carotid bifurcation disease. METHODS: Carotid stenting with self-expanding nitinol stents was evaluated in 261 patients (157 men; mean age 70.9+/-9.7 years, range 41-90) treated at 33 clinical sites. Among these patients, 141 (54.3%) were symptomatic, and 71 (27.2%) had postendarterectomy restenotic lesions. An embolus protection device became available in the latter third of the study. The primary endpoint of the study was the 30-day composite occurrence of major adverse clinical events (all deaths, strokes, or myocardial infarctions [MI]). At 1 year, the endpoint included all deaths, strokes, or MIs at 30 days, plus all deaths or ipsilateral strokes between 31 days and 1 year. RESULTS: SMART stents were placed in 147 (56%) patients and Precise stents in 107 (41%); 7 (3%) patients were treated with non-study stents. Lesion success, defined as <30% postprocedural residual stenosis, was achieved in 249 (95%). An AngioGuard filter was used in 85 patients; of 90 filters employed, 78 (87%) were successfully deployed and retrieved. Visible material was noted in 42 (54%) retrieved filters. One (0.4%) stent thrombosis occurred at <30 days, and no restenotic lesions >80% were noted in up to 1 year of follow-up. At 30 days, stroke occurred in 16 (6.1%) patients, MI in 1 (0.4%), and 2 (0.8%) patients died. The 30-day rate of stroke, MI, or death was 6.9%. Major ipsilateral stroke occurred in 4 (1.5%) patients between 0 and 30 days; no new major ipsilateral strokes were noted up to 1 year. By Kaplan-Meier analysis, the 1-year risk of stroke, MI, or death was 10.9%+/-2.0%. The 1-year risk of major ipsilateral stroke was significantly lower in patients treated with embolus protection devices (0.0% versus 2.3%, p=0.05). CONCLUSIONS: The use of nitinol self-expanding stents in the carotid position appears to be a safe and efficacious alternative for the treatment of carotid bifurcation disease. The addition of embolus protection devices may diminish the risk of postprocedural major ipsilateral strokes.

Adult↗
PubMed2004

Protected carotid-artery stenting versus endarterectomy in high-risk patients.

BACKGROUND: Carotid endarterectomy is more effective than medical management in the prevention of stroke in patients with severe symptomatic or asymptomatic atherosclerotic carotid-artery stenosis. Stenting with the use of an emboli-protection device is a less invasive revascularization strategy than endarterectomy in carotid-artery disease. METHODS: We conducted a randomized trial comparing carotid-artery stenting with the use of an emboli-protection device to endarterectomy in 334 patients with coexisting conditions that potentially increased the risk posed by endarterectomy and who had either a symptomatic carotid-artery stenosis of at least 50 percent of the luminal diameter or an asymptomatic stenosis of at least 80 percent. The primary end point of the study was the cumulative incidence of a major cardiovascular event at 1 year--a composite of death, stroke, or myocardial infarction within 30 days after the intervention or death or ipsilateral stroke between 31 days and 1 year. The study was designed to test the hypothesis that the less invasive strategy, stenting, was not inferior to endarterectomy. RESULTS: The primary end point occurred in 20 patients randomly assigned to undergo carotid-artery stenting with an emboli-protection device (cumulative incidence, 12.2 percent) and in 32 patients randomly assigned to undergo endarterectomy (cumulative incidence, 20.1 percent; absolute difference, -7.9 percentage points; 95 percent confidence interval, -16.4 to 0.7 percentage points; P=0.004 for noninferiority, and P=0.053 for superiority). At one year, carotid revascularization was repeated in fewer patients who had received stents than in those who had undergone endarterectomy (cumulative incidence, 0.6 percent vs. 4.3 percent; P=0.04). CONCLUSIONS: Among patients with severe carotid-artery stenosis and coexisting conditions, carotid stenting with the use of an emboli-protection device is not inferior to carotid endarterectomy.

Adult↗
PubMed2004

Advances in vascular brachytherapy over the last 10 years: focus on femoropopliteal applications.

Restenosis and the need for repeated interventions after percutaneous transluminal angioplasty (PTA) remain major drawbacks limiting a widespread application of this minimally invasive technique in the femoropopliteal segment. During the last decade, vascular brachytherapy (BT) emerged as a promising, novel technology with the potential to reduce the rates of restenosis. Meanwhile, several randomized controlled trials have suggested beneficial short and midterm effects of BT in the femoropopliteal arteries. However, despite substantial advances, many questions remain regarding the utility of vascular BT and its dissemination as a practical tool to prevent restenosis. The risk of complications, such as late stent thrombosis, edge effect, catch-up late restenosis, and potential aneurysm formation, as well as the logistical issues associated with the use of this technology in the catheterization laboratory, are delaying the acceptance of BT for routine use. This article reviews the developments of BT for restenosis prevention during the past decade, focusing on implications for peripheral endovascular treatment.

Angioplasty, Balloon↗
PubMed2003

Five-year interim comparison of the Guidant bifurcated endograft with open repair of abdominal aortic aneurysm.

OBJECTIVE: This study was undertaken to compare 1-year and 5-year results of endovascular repair of abdominal aortic aneurysm (AAA) with the Guidant/EVT bifurcated graft system with results of open repair. METHODS: This was a prospective, nonrandomized, concurrent controlled study that compared results of endovascular versus open repair of AAA. The Phase II study with the EGS delivery system included 268 patients in 18 US medical centers; and the Phase III trial with the Ancure delivery system incuded 305 patients in 21 US institutions. Data were internally and externally audited and subjected to periodic review by the US Food and Drug Administration. The control group of 111 patients were excluded from endovascular repair with a tube graft because of anatomic considerations, but were otherwise comparable to the experimental group. Patients in the control group underwent conventional open surgical repair concurrently with patients who underwent EGS repair in 18 US institutions. RESULTS: Five hundred thirty-one of 573 patients (92.7%) underwent successful implantation of the Guidant/EVT bifurcated endograft. The combined major morbidity and mortality in the endograft group was 28.8%, compared with 44.1% in the open control group. Additional benefits in the endograft group included shorter hospital stay (2 days vs 6 days), less surgical blood loss (400 mL vs 800 mL), and less intensive care unit use (33% vs 94%). These early results are reported on an intent-to-treat basis; in all patients an attempt was made to treat with the endovascular graft, including those patients in whom conversion to standard open repair was necessary during the primary procedure. Three hundred nineteen patients were selected for long-term follow-up to 5 years, on the basis of date of implantation; ie, patients with the earliest implantations were followed up for 5 years. The primary purpose of long-term follow-up was to obtain data on long-term efficacy of the graft; thus only patients in whom implantation was successful were selected. No patient has experienced an aneurysm rupture to date. Survival (Kaplan- Meier method) in the experimental group was 68.1%, compared with 77.2% in the control group (P = NS). At 60 months, 74.4% of patients (32 of 43) were free of endoleak. There were no type I or type III endoleaks remaining. Aneurysm sac diameter decreased or remained stable in 97.6% of patients (41 of 42) and increased in only 1 patient. During the course of long-term follow-up, post-procedural conversion to open repair was required in only 9 patients (2.8%). CONCLUSION: The EVT/Guidant bifurcated graft is effective in preventing AAA rupture, and long-term survival is comparable to that with open repair.

Aged↗
PubMed2003

Delayed aortic aneurysm enlargement due to endotension after endovascular abdominal aortic aneurysm repair.

Abdominal aortic aneurysm (AAA) enlarges after successful endovascular repair, because of persistent blood flow within the aneurysm sac, or endoleak. In the absence of detectable endoleak, AAA may still expand, in part because of persistent pressurization within the excluded aneurysm, or endotension. We report three patients who underwent successful endovascular AAA repair in whom postoperative surveillance showed aneurysm regression, yet delayed AAA enlargement without demonstrable endoleak developed in all three patients. Endotension was confirmed in all three patients at elective open conversion. Our study underscores the significance of endotension as a mechanism of delayed aneurysm enlargement after successful endovascular AAA repair.

Aged↗
PubMed2003

In vitro evaluation of a retrievable low-profile nitinol vena cava filter.

PURPOSE: To evaluate the clot-trapping ability, stability, and migration of a new low-profile, retrievable inferior vena cava (IVC) filter in an in-vitro model. MATERIALS AND METHODS: The SafeFlo IVC filter consists of two superelastic nitinol wires that form a double-ring platform and spiral filter. The filter is collapsed into a 5-6-F catheter and delivered into the IVC model. The in-vitro model closely simulates the physical parameters of flow in the human IVC. Human blood clots of 2-mm and 4-mm diameters and 3-cm lengths were injected into the flow system in sets of five clots. Filter delivery and retrieval were performed in every series. Filtration was evaluated in IVC models of 20-mm and 24-mm lumen diameter in vertical and horizontal positions. Stability and migration of the filter were evaluated by direct vision of maintenance of position and shape before and after clot trapping. RESULTS: Filter delivery and retrieval were straightforward and repeatable in a total of 20 procedures. The filters maintained shape and position throughout the study. A total of 248 clots were injected and 225 (90.7%) were trapped. The individual tests in horizontal and vertical positions with either clot size demonstrated trapping rates of 85.7%-97.1%. CONCLUSIONS: The SafeFlo IVC filter is a stable and effective filter in an in-vitro model. The filter design is amenable to simple delivery and retrieval.

Alloys↗
PubMed2003

Implications of problematic access in transluminal endografting of abdominal aortic aneurysm.

PURPOSE: Despite careful preoperative assessment, problematic access to the abdominal aorta for transluminal endografting (TE) of abdominal aortic aneurysm (AAA) is sometimes encountered. This study identifies preoperative risk factors predictive of problematic access and determines the impact of problematic access on outcomes. MATERIALS AND METHODS: Three hundred twenty-one consecutive TE procedures for AAA were divided into two groups: group A, which had access problems (n = 74), and group B, which had none (n = 247). RESULTS: Logistic regression analysis of risk factors showed that (i) a pulmonary risk score of 3 (P <.001; odds ratio, 11.2), (ii) a hyperlipidemia score of 3 (P =.004; odds ratio, 2.6), and (iii) a small body (short height with low weight, P =.003; odds ratio, of 4.2) were independent risk factors for problematic access. Outcomes compared included rates of perioperative mortality, aborted procedure, surgical conversion, major complication, limb complication, and endoleak. The perioperative mortality rate was higher in group A (6.8% vs 1.2%; P =.018) and procedures were more likely to be aborted in patients in group A (12.2% vs 0%; P <.001). Rates of surgical conversion, major complication, and limb complication were not different between the two groups. The endoleak rate was higher in group B (10.8% vs 26.7%; P =.004). Logistic regression analysis showed that problematic access was an independent risk factor (P =.004; odds ratio, 12.0) for perioperative mortality. CONCLUSIONS: Moderate to severe chronic obstructive pulmonary disease and hyperlipidemia, both risk factors for atherosclerosis, were related to problematic access in this series. Small body size was another factor related to problematic access. Problematic access was an independent risk factor for perioperative mortality.

Aged↗
PubMed2003

Cutting balloon to treat carotid in-stent stenosis: technical note.

Carotid artery in-stent stenosis, a possible long-term complication of carotid angioplasty and stenting, is currently treated by inflation of a non-compliant angioplasty balloon. Better initial results and less recurrence of stenosis have been documented in the coronary literature with the use of the Cutting Balloon (CB, Boston Scientific Interventional Technologies, San Diego, California) for angioplasty, in comparison with traditional balloon angioplasty. We report our collective experience with the use of the CB to treat carotid in-stent stenosis in three patients. Excellent angiographic and clinical results were achieved. No complications occurred. The lesions in two patients were successfully treated with the CB alone; adjunctive stent placement was required in a third patient. Our experience demonstrates the feasibility and safety of the CB for the treatment of carotid in-stent stenosis in three patients. Due to the less traumatic nature of this balloon, its use may result in a lower occurrence of in-stent stenosis as compared to a conventional angioplasty balloon. To our knowledge, this is the first report of the use of the CB for carotid in-stent stenosis.

Adult↗
PubMed2002

The future of catheter-based angiography: implications for the vascular interventionalist.

Based on the assumptions mentioned previously, the author makes the following predictions regarding catheter-based angiography and related procedures: 1. Most diagnostic angiography will be performed with noninvasive methods. In the peripheral circulation. MRA will be the predominant method, with CTA having an important role in aortic imaging and coronary imaging. MRA will have increased use for elective diagnosis and in clinical emergencies. 2. Catheter-based angiography will have an important role as an adjunct or preliminary procedure related to interventions. This is significant for planning catheter development and functionality of future angiographic equipment. 3. The need for angiographic equipment will continue to grow despite this decrease in diagnostic application, as a result of increase in interventional therapy. This increase in therapy will be a result of a variety of factors, including aging population, early diagnosis, and increasing acceptance of less invasive therapy. 4. Interventionists should be considering and planning for vascular imaging devices--MRA, CTA, and US--to be included as part of the interventional sections and the workload. 5. Cardiovascular imaging should be a clinical imaging specialty, with patient interaction at the time of imaging. 6. These changes should be embraced by vascular interventionalists, who should incorporate these tools into their clinical practice. 7. The changes, if they occur as predicted, will create significant problems in training skilled interventionists who will not have the foundation of diagnostic angiography on which to build complex endovascular skills.

Angiography↗