Design and Verification of Shape Memory Polymer Embolization Devices for Peripheral Indications

Polyurethane shape memory polymers (SMPs) have found a variety of uses in the medical industry in the form of self-tightening sutures, suture anchors, ligament fixation devices, vascular stents, and thrombectomy devices. New formulations of polyurethane SMP scaffolds are gaining significant interest for use in vascular embolization procedures. These scaffolds have demonstrated rapid time to occlusion, improved healing, and favorable biocompatibility, and they eliminate the need to implant multiple devices to achieve stable occlusion, significantly reducing procedure times and the total cost of treatment. Described here are various methods used to fabricate SMP scaffolds, indications for SMP scaffold embolization, advantages of using these scaffolds in embolization procedures, results seen in vivo and in vitro to verify the safety and efficacy of the SMP scaffolds, and future directions for SMP scaffolds that will propel the technology to significant use beyond vessel occlusion. The research described in this work resulted in the creation of novel embolic devices that have the potential to drastically reduce the cost of endovascular embolization procedures by reducing the number of devices required for treatment, radiation time, the need for repeat procedures, and the time to complete healing of the treated vessel. These devices also demonstrated resistance to undesired thromboembolism in vitro, while also exerting negligible radial force on the vessel endothelium to minimize the likelihood of vessel rupture or perforation. In vitro verification testing demonstrated that this device appears to be safe and effective for embolization within the peripheral vasculature. This work also represented the first verification of the echogenicity of shape memory polymer foam devices in vitro. In addition, this research solidified the designation of polyurethane shape memory polymer foam as a platform technology that can be combined with other material systems to create shape memory occlusive devices with enhanced fluid uptake and bactericidal properties

Design and Verification of Shape Memory Polymer Embolization Devices for Peripheral Indications

Polyurethane shape memory polymers (SMPs) have found a variety of uses in the medical industry in the form of self-tightening sutures, suture anchors, ligament fixation devices, vascular stents, and thrombectomy devices. New formulations of polyurethane SMP scaffolds are gaining significant interest for use in vascular embolization procedures. These scaffolds have demonstrated rapid time to occlusion, improved healing, and favorable biocompatibility, and they eliminate the need to implant multiple devices to achieve stable occlusion, significantly reducing procedure times and the total cost of treatment. Described here are various methods used to fabricate SMP scaffolds, indications for SMP scaffold embolization, advantages of using these scaffolds in embolization procedures, results seen in vivo and in vitro to verify the safety and efficacy of the SMP scaffolds, and future directions for SMP scaffolds that will propel the technology to significant use beyond vessel occlusion. The research described in this work resulted in the creation of novel embolic devices that have the potential to drastically reduce the cost of endovascular embolization procedures by reducing the number of devices required for treatment, radiation time, the need for repeat procedures, and the time to complete healing of the treated vessel. These devices also demonstrated resistance to undesired thromboembolism in vitro, while also exerting negligible radial force on the vessel endothelium to minimize the likelihood of vessel rupture or perforation. In vitro verification testing demonstrated that this device appears to be safe and effective for embolization within the peripheral vasculature. This work also represented the first verification of the echogenicity of shape memory polymer foam devices in vitro. In addition, this research solidified the designation of polyurethane shape memory polymer foam as a platform technology that can be combined with other material systems to create shape memory occlusive devices with enhanced fluid uptake and bactericidal properties

Volatilization Losses of Granular Formulations of Chlorethoxyfos and Terbufos From Soil

A technique was developed to quantify volatilization losses of chlorethoxyfos and terbufos from soil in laboratory and field studies during 1988 and 1989 at Brookings, South Dakota. In laboratory studies, treatments were arranged in 16 experimental units, which represented four replications of four samples. Treatments included chlorethoxyfos 10G at 1.1 kg/ha and terbufos 15G at 1.1 kg/ha. In field studies, treatments were arranged in a randomized complete block design replicated four times. Treatments included the following: chlorethoxyfos 5GM, banded and in-furrow; and terbufos 15G, banded and in-furrow. Volatilization recovery results indicated that chlorethoxyfos and terbufos were most volatile when applied banded to the soil surface, with more than 75% of total recovery occuring [sic] from initial application to 11 days after application. Soil moisture and soil temperature affected recoveries of the insecticides with a diurnal pattern. Data from concurrent corn rootworm efficacy studies revealed no significant differences in pest control between banded and in-furrow treatments of chlorethoxyfos and terbufos. This suggests then, that the insecticides should be placed in-furrow to reduce volatilization losses. This document contains two manuscripts written for publication in entomological journals. Research for these studies was performed during 1988 and 1989 on the Corn Insects Research project at South Dakota State University

Vascular prosthesis for leak prevention during endovascular aneurysm repair

An embodiment includes a process for treating an abdominal aortic aneurysm (AAA) endoleak with a shape memory polymer (SMP) foam device. First, a bifurcated stent graft is placed within the aneurysm while a micro guidewire is positioned within the aneurysm for future catheter access. Second, after placing the iliac graft extension, a catheter is introduced over wire to deliver embolic foams. Third, embolic foams expand and conform to the aneurysm wall. Fourth, embolic foams create a stable thrombus to prevent endoleak formation by isolating peripheral vessels from the aneurysm volume.U

Vascular prosthesis for leak prevention during endovascular aneurysm repair

An embodiment includes a process for treating an abdominal aortic aneurysm (AAA) endoleak with a shape memory polymer (SMP) foam device. First, a bifurcated stent graft is placed within the aneurysm while a micro guidewire is positioned within the aneurysm for future catheter access. Second, after placing the iliac graft extension, a catheter is introduced over wire to deliver embolic foams. Third, embolic foams expand and conform to the aneurysm wall. Fourth, embolic foams create a stable thrombus to prevent endoleak formation by isolating peripheral vessels from the aneurysm volume.U

Hemorrhage management system

An embodiment includes a wound dressing comprising: a shape memory polymer (SMP) foam, including open cells, having first and second states; and a hydrogel (HG) included within the cells; wherein (a) in a first position a composite, including the SMP foam and the HG, is configured to be located proximate a hemorrhagic tissue with the SMP foam in the first state; (b) in a second position the composite is configured to be expanded to the second state against the hemorrhagic tissue when the SMP foam is plasticized at 37? C. depressing a glass transition temperature (Tg) of the SMP foam to below 25? C. Other embodiments are described herein.U

Hemorrhage management system

An embodiment includes a wound dressing comprising: a shape memory polymer (SMP) foam, including open cells, having first and second states; and a hydrogel (HG) included within the cells; wherein (a) in a first position a composite, including the SMP foam and the HG, is configured to be located proximate a hemorrhagic tissue with the SMP foam in the first state; (b) in a second position the composite is configured to be expanded to the second state against the hemorrhagic tissue when the SMP foam is plasticized at 37? C. depressing a glass transition temperature (Tg) of the SMP foam to below 25? C. Other embodiments are described herein.U

Hemorrage management system

An embodiment includes a wound dressing comprising: a shape memory polymer (SMP) foam, including open cells, having first and second states; and a hydrogel (HG) included within the cells; wherein (a) in a first position a composite, including the SMP foam and the HG, is configured to be located proximate a hemorrhagic tissue with the SMP foam in the first state; (b) in a second position the composite is configured to be expanded to the second state against the hemorrhagic tissue when the SMP foam is plasticized at 37° C. depressing a glass transition temperature (Tg) of the SMP foam to below 25° C. Other embodiments are described herein.U

Hemorrhage management system

An embodiment includes a wound dressing comprising: a shape memory polymer (SMP) foam, including open cells, having first and second states; and a hydrogel (HG) included within the cells; wherein (a) in a first position a composite, including the SMP foam and the HG, is configured to be located proximate a hemorrhagic tissue with the SMP foam in the first state; (b) in a second position the composite is configured to be expanded to the second state against the hemorrhagic tissue when the SMP foam is plasticized at 37 C. depressing a glass transition temperature (Tg) of the SMP foam to below 25 C. Other embodiments are described herein.U