Feasibility of FiberNet® embolic protection system in patients undergoing angioplasty for atherosclerotic renal artery stenosis.

OBJECTIVE: To evaluate the procedural safety and filter efficiency of Lumen Biomedical FiberNet® embolic protection system in conjunction with primary stenting of ostial atherosclerotic renal artery lesions. BACKGROUND: There is limited data regarding the utility of distal embolic protection devices in renal artery angioplasty and stenting. METHODS: Patients with angiographically severe (≥70%) renal artery stenosis were prospectively enrolled if one or more inclusion criteria met: resistant hypertension, progressive chronic kidney disease, unexplained heart failure, or flash pulmonary edema. Patients underwent renal artery angioplasty and stenting with utilization of the Lumen Biomedical FiberNet® EPS. The protection devices and aspirate were analyzed for degree of atheromatous particles. Procedural safety and clinical outcomes were assessed through 6 months. RESULTS: Twenty patients were prospectively enrolled at five centers; average age 73.8 (±9.5) years, mean baseline eGFR 60.8 cm(3) min(-1). Twenty-five renal artery stenting procedures were performed. Device and procedural success were achieved in 100% of cases. All patients tolerated the procedure without any adverse events. Embolic debris was captured in all cases. Debris analysis of the distal protection system displayed an average post procedure atheroma area of 51.31 mm(2). There was no clinical evidence of peripheral atheroembolization through 30-days follow-up. No subjects progressed to temporary or permanent renal replacement therapy. Favorable trends in blood pressure control were observed at 6 months. CONCLUSION: The Lumen Biomedical FiberNet® embolic protection system is a safe and feasible method to prevent atheroembolization associated with angioplasty and stenting of renal artery ostial lesions.

Carotid artery revascularization in high surgical risk patients with the NexStent and the Filterwire EX/EZ: 1-year results in the CABERNET trial.

OBJECTIVE: The multicenter, single-arm CABERNET trial evaluated outcomes in high-surgical-risk patients with carotid artery stenosis treated with the NexStent plus FilterWire EX/EZ Emboli Protection System. BACKGROUND: For patients at high surgical risk, carotid artery stenting (CAS) offers a less invasive alternative to carotid endarterectomy (CEA). METHODS: The trial enrolled 454 high-surgical-risk patients with carotid stenosis by angiography > or = 50% for symptomatic patients and > or = 60% for asymptomatic patients. The comparator primary endpoint was the 1-year major adverse event (MAE, defined as any death, stroke, or myocardial infarction [MI]) rate. It was compared with a proportionally weighted objective performance criterion (OPC) of 12.1% representative of published CEA results in similar patients plus a prespecified noninferiority margin (delta) of 4%. A second primary endpoint was the composite rate of 30-day MAE plus late (31-365 days) ipsilateral stroke. RESULTS: Symptoms of carotid stenosis were present in 24.2% of patients; 36.6% of patients were considered high-surgical-risk due to comorbid risk factors and 63.4% due to anatomic risk factors. The rate of 30-day MAE plus late ipsilateral stroke was 4.7% (20/438). The comparator primary endpoint of 1-year MAE was 11.6% (51/438) and was noninferior to the OPC of 12.1% (95% upper confidence interval of 14.5% versus OPC plus delta of 16.1%, P = 0.005). Late ipsilateral stroke was 0.7% and target vessel revascularization at 1 year was 2.4%. CONCLUSIONS: The CABERNET trial demonstrates that CAS with NexStent and FilterWire is noninferior to (equivalent or better than) traditional CEA at 1 year in high-surgical-risk patients based on historical controls.

Carotid artery revascularization in high-surgical-risk patients using the Carotid WALLSTENT and FilterWire EX/EZ: 1-year outcomes in the BEACH Pivotal Group.

OBJECTIVES: The multicenter, single-arm BEACH (Boston Scientific EPI: A Carotid Stenting Trial for High-Risk Surgical Patients) evaluated outcomes in high-surgical-risk patients with carotid artery stenosis treated with the Carotid WALLSTENT plus FilterWire EX/EZ Emboli Protection System (Boston Scientific, Natick, Massachusetts). BACKGROUND: Carotid artery stent (CAS) placement offers a less invasive alternative for high-risk surgical carotid endarterectomy (CEA) patients. METHODS: The trial enrolled 480 pivotal patients who were candidates for carotid revascularization but considered high surgical risk due to pre-specified anatomic criteria and/or medical comorbidities. The primary end point (all stroke, death, or Q-wave myocardial infarction [MI] through 30 days; non-Q-wave MI through 24 h; and ipsilateral stroke or neurologic death through 1 year) was compared with a proportionally weighted objective performance criterion (OPC) of 12.6% for published surgical endarterectomy results in similar patients, plus a pre-specified noninferiority margin of 4%. RESULTS: Among pivotal patients, 41.2% were at high surgical risk due to comorbid risk factors, and 58.8% due to anatomic risk factors; 76.7% were asymptomatic with flow-limiting carotid stenosis >80%. At 1 year, the composite primary end point occurred in 8.9% (40 of 447), with a repeat revascularization rate of 4.7%. With an upper 95% confidence limit of 11.5% for the primary composite end point, the BEACH trial results met the pre-specified criteria for noninferiority relative to the calculated OPC plus noninferiority margin (16.6%) for historical surgical CEA outcomes in similar patients (p < 0.0001 for noninferiority). CONCLUSIONS: The BEACH trial results demonstrate that CAS with the WALLSTENT plus FilterWire embolic protection is non-inferior (equivalent or better than) to CEA at 1-year in high-surgical-risk patients.

Cryoplasty for the treatment of femoropopliteal arterial disease: extended follow-up results.

PURPOSE: To report the findings from a multicenter study of patients treated with cryoplasty who were then followed for an average of > 2 years post-treatment. METHODS: Extended clinical follow-up was obtained for 70 patients (45 men; mean age 70.5 +/- 8.8 years) who originally received cryoplasty therapy to treat symptoms of intermittent claudication as part of a multicenter investigational device exemption (IDE) study. For all subjects, cryoplasty was used to treat stenoses or occlusions < or = 10 cm in the femoropopliteal arteries. The original IDE study protocol enrolled 102 patients with a primary endpoint of target lesion patency at 9 months post-treatment. This collection of additional longer term follow-up data was initiated 2.5 years after the onset of study enrollment. RESULTS: Extended clinical follow-up ranged from 11 to 41 months (mean 31). The clinical patency rate (freedom from target lesion revascularization) calculated by the Kaplan-Meier method was 83.2% after the original follow-up period of 300 days. After > 3 years (1253 days), the clinical patency rate was well maintained at 75.0%. CONCLUSIONS: Long-term data indicate that cryoplasty is a durable therapy, with relatively low long-term restenosis rates compared to other endovascular treatment approaches.

Cryoplasty for the treatment of femoropopliteal arterial disease: results of a prospective, multicenter registry.

PURPOSE: Despite suboptimal results, angioplasty of femoropopliteal arterial lesions has been a mainstay of endovascular therapy for many years. The recent introduction of cryoplasty marks a potential advance in the ability to effectively treat peripheral arterial atherosclerotic stenoses. This article presents the results of a prospective, multicenter trial that evaluated the efficacy of cryoplasty for femoropopliteal disease. MATERIALS AND METHODS: One hundred two patients with claudication and lesions of the superficial femoral and popliteal arteries of no greater than 10 cm were studied. All patients were treated with a primary strategy of stand-alone cryoplasty with use of the PolarCath cryoplasty system. The primary endpoints of the study were acute technical success and clinical patency at 9 months. Technical success was defined as the ability to achieve residual angiographic stenosis no greater than 30% and residual stenosis less than 50% by duplex ultrasound (US) imaging. Clinical patency was defined as freedom from target lesion revascularization within 9 months. Primary patency was defined by a duplex US systolic velocity ratio no greater than 2.0. RESULTS: A total of 102 patients were enrolled at 16 centers. Of those treated, 31% had diabetes and 31% were active cigarette smokers. The majority of the lesions were confined to the superficial femoral artery (84.3%) and 14.7% presented with total occlusions. The mean vessel diameter treated was 5.5 mm +/- 0.5, the mean stenosis diameter was 87% +/- 10%, and the mean lesion length was 4.7 cm +/- 2.6. The technical success rate was 85.3% with a mean residual stenosis after cryoplasty of 11.2% +/- 11.2% (P < .05 vs baseline). Clinical patency in this group was 82.2%, as only 16 patients required target lesion revascularization during the 9-month surveillance period. Primary patency determined by duplex US was 70.1%. CONCLUSIONS: Cryoplasty demonstrated a high degree of acute angiographic success and a low frequency of target lesion revascularization. The patency rate observed compares favorably to that previously documented with conventional angioplasty.

In vitro evaluation of vascular endothelial and smooth muscle cell survival and apoptosis in response to hypothermia and freezing.

The success of endovascular techniques such as balloon angioplasty and stenting in the treatment of atherosclerotic vascular disease has been limited by an aggressive proliferative response leading to neointimal hyperplasia and re-stenosis. A new endovascular therapy combining cold treatment with balloon dilation has been proposed to prevent arterial re-stenosis. In order to evaluate the potential of this application, studies were conducted investigating the effects of hypothermia and freezing on human arteries at the cellular level. Cultured arterial endothelial cells and smooth muscle cells were chilled or frozen under controlled thermal conditions. The viability response of the cells was measured with a variety of assays quantifying necrosis, apoptosis, and cell proliferation. These data establish correlations between thermal conditions and the extent and nature of arterial freezing injury. Arterial smooth muscle cells were found to be susceptible to freeze-induced apoptosis in a temperature range of -5 to -15 degrees C. Endovascular cryotherapy designed to induce apoptosis in arterial smooth muscle cells may limit neointimal formation and thereby improve the durability of conventional angioplasty.

The clinical application of cryoplasty for infrainguinal peripheral arterial disease.

Interventional outcomes for peripheral arterial disease of the lower extremity have long suffered from suboptimal patency rates. Many drugs and devices have been studied in an attempt to alter the aggressive neointimal response witnessed in infra-inguinal vessels with little success. Cryoplasty, a recent entrant into the endovascular arena, combines the time-tested mechanics of percutaneous transluminal angioplasty with the biologically favorable effects of cryotherapy. Cryoplasty specifically targets infra-inguinal lesions and minimizes neointimal proliferation via induction of apoptosis in the cell lines that contribute to restenosis. In addition, the mechanistic effects on the architecture of the vessel wall and the plaque itself have been found to reduce the likelihood of significant dissection following cryoplasty as compared with those expected with percutaneous transluminal angioplasty. Several clinical trials have demonstrated the efficacy of cryoplasty in patients with superficial femoral and popliteal arterial disease, as well as in critical limb ischemia patients with tibioperoneal arterial disease. Current clinical applications in the lower extremity will be reviewed along with technical tips for device use and opportunities for device synergy with other existing technologies.

Cryoplasty for femoropopliteal arterial disease: late angiographic results of initial human experience.

PURPOSE: A new form of angioplasty, called cryoplasty, was developed to improve the late results typically associated with percutaneous transluminal angioplasty. Cryoplasty combines the dilation force of percutaneous transluminal angioplasty with the delivery of cold thermal energy to the vessel wall. This study reports the authors' early clinical experience with cryoplasty in patients with femoropopliteal disease. MATERIALS AND METHODS: Fifteen patients with femoropopliteal arterial lesions were treated with cryoplasty (CryoVascular Systems, Los Gatos, CA). Cryoplasty was performed at 6 atm of pressure and delivered at -10 degrees C for 60 seconds. The ankle-brachial index (ABI) was measured at baseline, 24 hours after cryoplasty, and at 1 and 3 months during follow-up. Repeated angiography was performed at 6 and 18 months to determine short-term and late primary patency. RESULTS: Cryoplasty was technically successful in 93% of patients (< 30% residual stenosis and less then grade C dissection). ABIs at baseline were 0.64 +/- 0.08 and improved the day after cryoplasty to 0.95 +/- 0.09 (P < .05). ABIs were well maintained at 1 and 3 months with measurements of 0.94 +/- 0.09 and 0.92 +/- 0.10, respectively (P < .05 vs baseline). Baseline angiographic diameter stenosis improved significantly immediately following cryoplasty (86% +/- 12% to 16% +/- 3%; P < .05). Angiography at 6 months revealed 0% binary restenosis and insignificant change in residual stenosis from the acute cryoplasty results (16 +/- 3% vs 21 +/- 5%; P = NS). Late angiographic follow-up at 14 months +/- 4 demonstrated primary patency of 83.3%. CONCLUSION: Cryoplasty was able to achieve substantial dilation of femoropopliteal lesions with well-preserved late angiographic patency. Cryoplasty represents a potential advance in the field of endovascular medicine.