A porcine model of thoracic aortic aneurysms created with a retrievable drug infusion stent graft mirrors human aneurysm pathophysiology.

Objective: Aneurysm pathophysiology remains poorly understood, in part from the disparity of murine models with human physiology and the requirement for invasive aortic exposure to apply agents used to create aneurysm models. A retrievable drug infusion stent graft (RDIS) was developed to isolate the aortic wall intraluminally for drug exposure. We hypothesized that an RDIS could deliver aneurysm-promoting enzymes to create a porcine model of thoracic aneurysms without major surgical exposure.

Gluteal and thigh compartment syndrome after open abdominal aortic aneurysm repair.

Although compartment syndrome (CS) can occur in any myofascial compartment, the thigh and buttock are among the least common. CS is characterized by an increase in pressure of a myofascial compartment that results in a reduction of capillary blood flow and myonecrosis. Although >75% of cases of CS occur after long bone fractures, acute CS can also occur from nontraumatic and vascular etiologies.

A self calibrating, magnetic sensor approach accurately positions an aortic damage control stent in a porcine model.

Objectives: Non-compressible torso hemorrhage remains a high mortality injury, with difficulty mobilizing resources before exsanguination. Previous studies reported on a retrievable stent graft for damage control and morphometric algorithms for rapid placement, yet fluoroscopy is impractical for the austere environment. We hypothesized that magnetic sensors could be used to position stents relative to an external magnet placed on an anatomic landmark, whereas an electromagnet would allow self-calibration to account for environmental noise.

A System to Track Stent Location in the Human Body by Fusing Magnetometer and Accelerometer Measurements.

This paper will introduce a simple locating system to track a stent when it is deployed into a human artery. The stent is proposed to achieve hemostasis for bleeding soldiers on the battlefield, where common surgical imaging equipment such as fluoroscopy systems are not available. In the application of interest, the stent must be guided to the right location to avoid serious complications.

A dumbbell rescue stent graft facilitates clamp-free repair of aortic injury in a porcine model.

Objective: Noncompressible torso hemorrhage is a high-mortality injury. We previously reported improved outcomes with a retrievable rescue stent graft to temporize aortic hemorrhage in a porcine model while maintaining distal perfusion. A limitation was that the original cylindrical stent graft design prohibited simultaneous vascular repair, given the concern for suture ensnarement of the temporary stent.

A prebifurcated axillobifemoral polytetrafluoroethylene graft simplifies carotid to carotid to subclavian bypass.

The use of thoracic endovascular aortic repair for thoracic aortic disease will necessitate cervical debranching in cases involving the proximal arch. We have presented the case of a 57-year-old athletic woman who had developed a type A dissection that extended to the bilateral iliac arteries. After hemiarch repair, she underwent staged cervical debranching with carotid-carotid-subclavian bypass using a prebifurcated axillobifemoral graft and subsequent thoracic endovascular aortic repair.

The anchor point algorithm: A morphometric analysis of anatomic landmarks to guide placement of temporary aortic Rescue stent grafts for noncompressible torso hemorrhage.

Background: Noncompressible hemorrhage remains a high-mortality injury, which requires rapid damage control within minutes to avoid exsanguination. Retrievable stent grafts offer perfusion preserving hemorrhage damage control, and yet algorithms for device selection and positioning are lacking for an anatomically diverse human population. We hypothesized that easily acquired external measurements could be used to rapidly triage patients to receive one of several presized stents and that these metrics may further predict a single target on the aorta by which to optimize both mesenteric perfusion and aortic hemorrhage control.

Extra-Anatomic Bypass and Excision is Superior to Graft Salvage Attempts with Antibiotic Beads to Treat Vascular Graft Infections in the Groin.

Background: This study aimed to determine if conventional extra-anatomic bypass and graft removal versus aggressive attempts at graft preservation have better survival and limb salvage in patients with localized groin wound infections of vascular grafts.

Methods: We conducted a retrospective review of 53 consecutive patients with vascular graft infections presenting in the groin. Treatment groups consisted of group 1 (extra-anatomic bypass and graft excision, n = 22) and group 2 (initial graft preservation attempts with utilization of antibiotic beads, n = 31).

Understanding the Mechanism of Drug Transfer and Retention of Drug-Coated Balloons.

Objective: The purpose of this study was to determine the impact of varying inflation parameters on paclitaxel delivery and retention using a commercially available DCB.

Background: Drug-coated balloons (DCB) have become the standard treatment for peripheral artery disease. Clinical data suggest that varying DCB delivery parameters directly impact patient outcome.

In vitro and In vivo assessment of a novel organ perfusion stent for successful flow separation in donation after cardiac death.

Shortage of healthy donors' organs has appeared as one of the main challenges for organ transplantation. This study focuses on the novel endovascular device development to increase the number of available organs from cardiac death donors. The primary objective of this study is the design validation of a newly developed stent graft for the abdominal organ perfusion with cardiac blood flow isolation.

A retrievable, dual-chamber stent protects against warm ischemia of donor organs in a model of donation after circulatory death.

Background: Ischemic injury during the agonal period of donation after circulatory death donors remains a significant barrier to increasing abdominal transplants. A major obstacle has been the inability to improve visceral perfusion, while at the same time respecting the ethics of the organ donor. A retrievable dual-chamber stentgraft could potentially isolate the organ perfusion from systemic hypotension and hypoxia, without increasing cardiac work or committing the donor.

Assessment of mechanical and biocompatible performance of ultra-large nitinol endovascular devices fabricated via a low-energy laser joining process.

Nitinol is an excellent candidate material for developing various self-expanding endovascular devices due to its unique properties such as superelasticity, biocompatibility and shape memory effect. A low-energy laser joining technique suggests a high potential to create various large diameter Nitinol endovascular devices that contain complex geometries. The primary purpose of the study is to investigate the effects of laser joining process parameters with regard to the mechanical and biocompatible performance of Nitinol stents.

A three-tier Rescue stent improves outcomes over balloon occlusion in a porcine model of noncompressible hemorrhage.

Background: Noncompressible hemorrhage remains a high-mortality injury, and aortic balloon occlusion poses limitations in terms of distal ischemic injury. Our hypothesis was that a retrievable Rescue stent would confer improved outcome over aortic balloon occlusion.

Methods: A three-tier, retrievable stent graft was laser welded from nitinol and polytetrafluoroethylene to provide rapid thoracic and abdominal coverage with an interval bare metal segment to preserve visceral flow.

Comprehensive assessment of mechanical behavior of an extremely long stent graft to control hemorrhage in torso.

Traumatic vascular injuries, resulting from either civilian accidents or wounded soldiers, require new endovascular devices (i.e., stent graft) to rapidly control the excessive internal hemorrhage in torso region.

A novel customizable stent graft that contains a stretchable ePTFE with a laser-welded nitinol stent.

Customizable medical devices have recently attracted attentions both in dental and orthopedic device fields, which can tailor to the patients' anatomy to reduce the length of surgery time and to improve the clinical outcomes. However, development of the patient specific endovascular device still remains challenging due to the limitations in current 3D printing technology, specifically for the stent grafts. Therefore, our group has investigated the feasibility of a highly stretchable expanded-polytetrafluoroethylene (ePTFE) tube as a customizable graft material with the laser-welded nitinol backbone.

Damage control of caval injuries in a porcine model using a retrievable Rescue stent.

Objective: Early hemorrhage control before the operating room is essential to reduce the significant mortality associated with traumatic injuries of the vena cava. Conventional approaches present logistical challenges on the battlefield or in the trauma bay. A retrievable stent graft would allow rapid hemorrhage control in the preoperative setting when endovascular expertise is not immediately available and without committing a patient to the limitations of current permanent stents.

Advances in Materials for Recent Low-Profile Implantable Bioelectronics.

The rapid development of micro/nanofabrication technologies to engineer a variety of materials has enabled new types of bioelectronics for health monitoring and disease diagnostics. In this review, we summarize widely used electronic materials in recent low-profile implantable systems, including traditional metals and semiconductors, soft polymers, biodegradable metals, and organic materials. Silicon-based compounds have represented the traditional materials in medical devices, due to the fully established fabrication processes.

A Review of PMMA Bone Cement and Intra-Cardiac Embolism.

Percutaneous vertebroplasty procedure is of major importance, given the significantly increasing aging population and the higher number of orthopedic procedures related to vertebral compression fractures. Vertebroplasty is a complex technique involving the injection of polymethylmethacrylate (PMMA) into the compressed vertebral body for mechanical stabilization of the fracture. Our understanding and ability to modify these mechanisms through alterations in cement material is rapidly evolving.

A retrievable rescue stent graft and radiofrequency positioning for rapid control of noncompressible hemorrhage.

Background: Noncompressible hemorrhage of the torso remains a challenging surgical dilemma. Stent graft repair requires endovascular expertise, imaging, and inventory that are not available within the critical window of massive hemorrhage. We developed a retrievable stent graft for rapid hemorrhage.

An in vivo pilot study of a microporous thin film nitinol-covered stent to assess the effect of porosity and pore geometry on device interaction with the vessel wall.

Sputter-deposited thin film nitinol constructs with various micropatterns were fabricated to evaluate their effect on the vessel wall in vivo when used as a covering for commercially available stents. Thin film nitinol constructs were used to cover stents and deployed in non-diseased swine arteries. Swine were sacrificed after approximately four weeks and the thin film nitinol-covered stents were removed for histopathologic evaluation.

A novel compartmentalised stent graft to isolate the perfusion of the abdominal organs.

Donation after cardiac death has been adopted to address the critical shortage of donor organs for transplant. Recovery of these organs is hindered by low blood flow that leads to permanent organ injury. We propose a novel approach to isolate the perfusion of the abdominal organs from the systemic malperfusion of the dying donor.

A depleting antibody toward sca-1 mitigates a surge of CD34(+)/c-kit(+) progenitors and reduces vascular restenosis in a murine vascular injury model.

Objective: Vascular restenosis remains a major obstacle to long-term success after vascular intervention. Circulating progenitor cells have been implicated in restenosis, and yet it has remained unclear if these cells, particularly nonendothelial progenitors, have an active role in this pathologic process. We hypothesized that circulating CD34(+)/c-kit(+) progenitors would increase after vascular injury, mirrored by changes in the injury signal, stromal cell-derived factor 1α (sdf1α).

Dual chamber stent prevents organ malperfusion in a model of donation after cardiac death.

Background: The paradigm for donation after cardiac death subjects donor organs to ischemic injury. A dual-chamber organ perfusion stent would maintain organ perfusion without affecting natural cardiac death. A center lumen allows uninterrupted cardiac blood flow, while an external chamber delivers oxygenated blood to the visceral vessels.