The ABSORB Bioresorbable Scaffold Below the Knee (BTK) Study

Study Overview
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Brief Summary
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ABSORB BTK Study: A prospective, multicenter, controlled clinical evaluation of the use of a bioresorbable drug eluting stent in the arterial vasculature below the knee

Detailed Description
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The aim of this study is to evaluate the performance of a bioresorbable vascular scaffold (BVS) coated with the drug Everolimus. This will be used to treat short length blockages of up to 55mm (5.5cm) in arteries below the knee. This will be performed to treat patients who have severe leg pain or have developed skin ulcers or gangrene which are not healing due to insufficent blood supply. The ABSORB Everolimus Eluting Bioresorbable Vascular Scaffold works on similar principles of drug eluting stents which have been used for a considerable time in treating blocked arteries. However this product consists of a scaffold coated with a drug so rather than leaving a metallic stent in the blood vessel, this product primarily delivers the drug, gives mechanical support to the blood vessel and once it is no longer needed the scaffold absorbs into the body leaving no permanent metallic implant. This same device has been used safely and effectively in the arteries which supply the heart both in clinical trials and current practice and has also been evaluated in the leg arteries in a single-centre pilot study. This study aims to evaluate it's use in a larger number of patients in multiple centres and compare that to a historical control group of metal drug eluting stents. The study will evaluate both ultrasound and angiographic derived patency in those arteries out to a 36 month follow-up time point. This data will be collected in patients who fulfill the inclusion criteria and who are then treated and followed over time.

Official Title
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ABSORB BTK Study: A Prospective, Multi-center, Controlled Clinical Evaluation of the Use of a Bioresorbable Drug Eluting Stent (Absorb, Abbott Vascular) in the Arterial Vasculature Below the Knee

Conditions
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Ischemia, Peripheral Arterial Disease (PTA, Arterial Occlusive Diseases

Intervention / Treatment
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* Device: Absorb Bioresorbable Vascular Scaffold


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Stenotic (> 50%) or occlusive atherosclerotic disease of the distal popliteal or infrapopliteal arteries A maximum of two focal target lesions in one or more distal popliteal or infrapopliteal vessels Length of lesion is maximally 55 mm, allowing maximally 2 stents to be implanted Reference vessel diameter should be 2.5 mm-4 mm Symptomatic critical limb ischemia (Rutherford 3, 4, 5) Subject is able to take at least one type of thienopyridine (e.g. clopidogrel) and acetylsalicylic acid The patient must be > 18 years of age Life-expectancy of more than 12 months The patient has no child bearing potential or negative serum pregnancy test within 7 days of the index procedure The patient must be willing and able to return to the appropriate follow-up times for the duration of the study The patient must provide written patient informed consent that is approved by the ethics committee Exclusion Criteria: Patient refusing treatment The reference segment diameter is not suitable for available stent design. Unsuccessfully treated (>30% residual stenosis) proximal inflow limiting arterial stenosis Untreatable lesion located at the distal outflow arteries More than two infrapopliteal lesions in the same limb Previously implanted stent(s) or PTA at the same lesion site Lesion location requiring kissing stent procedure Lesion lies within or adjacent to an aneurysm Inflow-limiting arterial lesions left untreated The patient has a known allergy to heparin, Aspirin or other anticoagulant/anti-platelet therapies or a bleeding diatheses or is unable, or unwilling, to tolerate such therapies. The patient takes Phenprocoumon (Marcumar). The patient has a history of prior life-threatening contrast media reaction. The patient is currently enrolled in another investigational device or drug trial. The patient is currently breast-feeding, pregnant or intends to become pregnant. The patient is mentally ill or retarded. Subject has received a heart transplant or any other organ transplant or is on a waiting list for any organ transplant Subject is receiving or scheduled to receive anticancer therapy for malignancy within 30 days prior to or after the procedure Subject is receiving immunosuppression therapy, or has known serious immunosuppressive disease (e.g., human immunodeficiency virus), or has severe autoimmune disease that requires chronic immunosuppressive therapy (e.g., systemic lupus erythematosus, etc.) The patient should also not receive inhibitors of CYP3A (such as Itraconazole, and Erythromycin), or inducers of CYP3A (Cytochrome P450 3A4) (such as Rifampin) within 90 days following the procedure. Subject is receiving or is scheduled to receive chronic anticoagulation therapy (e.g., heparin, coumadin) Use of alternative therapy (e.g. atherectomy, cutting balloon, laser, radiation therapy) as part of the index procedure

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Bioresorbable Vascular Scaffold<br>Absorb Bioresorbable Vascular Scaffold | Device: Absorb Bioresorbable Vascular Scaffold<br>* Absorb Bioresorbable Vascular Scaffold<br>* Other names: BVS;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Angiographic patency | Freedom from angiographic binary in-scaffold restenosis (>50% stenosis) | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Technical success | Technical success defined as the ability to cross and dilate the lesion to achieve residual angiographic stenosis no greater than 30% and residual stenosis less than 50% by duplex ultrasound (US) imaging. | Procedure | 
| Haemodynamic primary, assisted primary and secondary patency | Haemodynamic primary, assisted primary and secondary patency as assessed by ultrasound | 1 month | 
| Haemodynamic primary, assisted primary and secondary patency | Haemodynamic primary, assisted primary and secondary patency as assessed by ultrasound | 6 months | 
| Haemodynamic primary, assisted primary and secondary patency | Haemodynamic primary, assisted primary and secondary patency as assessed by ultrasound | 12 months | 
| Haemodynamic primary, assisted primary and secondary patency | Haemodynamic primary, assisted primary and secondary patency as assessed by ultrasound | 24 months | 
| Haemodynamic primary, assisted primary and secondary patency | Haemodynamic primary, assisted primary and secondary patency as assessed by ultrasound | 36 months | 
| Limb salvage rate (LSR) | Limb salvage defined as 1 minus major amputation rate (major amputation is defined as at or above ankle, as opposed to minor amputation being at or below metatarsus preserving functionality of foot) | 12 months | 
| Target lesion revascularization (TLR) | Target lesion revascularization (TLR) is defined as a repeat intervention to maintain or re-establish patency within the region of the treated arterial vessel plus 5 mm proximal and distal to the treated lesion edge | 12 months | 
| Rutherford Category | Clinical success defined as an improvement of Rutherford classification of one class or more as compared to the pre-procedure Rutherford classification | 12 months | 
| Adverse clinical events | Clinical events defined as fatal, life-threatening, or judged to be severe by the investigator; resulted in persistent or significant disability; necessitated surgical or percutaneous intervention; or required prolonged hospitalization | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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angioplasty, stents, polymers, absorbable implants