Sentry Bioconvertible Inferior Vena Cava Filter: Study of Stages of Incorporation in an Experimental Ovine Model.

The Sentry inferior vena cava (IVC) filter is designed to provide temporary protection from pulmonary embolism (PE) and then bioconvert to become incorporated in the vessel wall, leaving a patent IVC lumen. Objective. To evaluate the performance and stages of incorporation of the Sentry IVC filter in an ovine model. Methods. Twenty-four bioconvertible devices and 1 control retrievable filter were implanted in the infrarenal IVC of 25 sheep, with extensive daily monitoring and intensive imaging. Vessels and devices were analyzed at early (≤98 days, n = 10) and late (180 ± 30 days, n = 14 study devices, 1 control) termination and necropsy time-points. Results. Deployment success was 100% with all devices confirmed in filtering configuration, there were no filter-related complications, and bioconversion was 100% at termination with vessels widely patent. By 98 days for all early-incorporation analysis animals, the stabilizing cylindrical part of the Sentry frame was incorporated in the vessel wall, and the filter arms were retracted. By 180 days for all late-incorporation analysis animals, the filter arms as well as frames were stably incorporated. Conclusions. Through 180 days, there were no filter-related complications, and the study devices were all bioconverted and stably incorporated, leaving all IVCs patent.

Safety and effectiveness of a polyvinyl alcohol barrier in reducing risks of vascular tissue damage during anterior spinal revision surgery.

STUDY DESIGN: This study was conducted as a controlled, prospective investigation to show the safety and efficacy of a polyvinyl alcohol (PVA) device in a sheep model. OBJECTIVE: To evaluate the ability of a permanent PVA hydrogel barrier to reduce the risk of potential vessel damage during anterior vertebral revision surgery, to provide a nonadhesive barrier at the surgical site, and to create a surgical revision plane of dissection. BACKGROUND: The development of scar tissue and adhesions presents a significant postoperative problem in spine surgery, where adhesion involvement of overlying structures can cause pain, neurovascular complications, and present a difficult surgical environment during revisions. METHODS: The devices were implanted onto the ventral surface of exposed lumbar intervertebral discs using an anterolateral approach. One disc separated from the study site was also exposed to serve as a control. Three sheep each were then evaluated with an explant procedure at 30 and 90 days. Extensive sampling was undertaken to evaluate gross anatomic, micropathologic, and biochemical environments and properties of the device. RESULTS: The structural properties and appearance of the device remained intact at both 30 and 90 days. The material remained flexible, hydrophilic, and soft, without visible resorption or decomposition. The material was well tolerated by the animal, with minimal histologic signs of inflammation or rejection. Tissue planes were easily able to be localized by the surgeon attempting to locate the prior surgical site at the time of resection. CONCLUSIONS: The PVA vessel shield effectively protected the structures overlying the sheep spine during revision, providing a clear dissection plane for resection at repeat surgery. The overlying structures separated from the previous surgical site with no adhesion, and allowed safe separation of adjacent tissues without the use of sharp dissection.

Vasomotor function after paclitaxel-coated balloon post-dilation in porcine coronary stent model.

OBJECTIVES: The purpose of this study was to evaluate endothelial function after post-dilation of bare-metal stents with paclitaxel-coated balloons (PCB) or non-drug-coated balloons (non-DCB) in a porcine model. BACKGROUND: DCB are an attractive alternative to drug-eluting stents because they provide short duration of drug exposure, while potentially inhibiting in-stent restenosis. Drug-eluting stents are associated with impaired endothelial function. It is unknown whether this abnormal vasomotor function is mitigated by reduced duration of drug exposure. METHODS: Thirteen pigs underwent bare-metal stent implantation (arteries, n = 30), followed by post-dilation with either PCB (SeQuent Please, B. Braun Melsungen AG, Berlin, Germany) (n = 17) or non-DCB (n = 13). Five pigs with unstented arteries (n = 14) were controls. Coronary vasomotion was assessed 1 month after stent implantation, using acetylcholine (Ach) and nitroglycerin. Measurements were obtained for distal segments. RESULTS: Angiographic late loss and histological area stenosis were similar between PCB and non-DCB. However, the percentage of diameter change in response to Ach was diminished with PCB (p < 0.05), when compared with either non-DCB or naive arteries. There was no difference between non-DCB and naive arteries. Inflammatory score and intramural fibrin grading were significantly greater in PCB than non-DCB (p < 0.05). Additionally, inflammatory cell infiltration in the stented segments correlated with the degree of percentage of diameter change in response to Ach, at distal regions. CONCLUSIONS: Post-dilation of bare-metal stents with PCB was associated with impaired vasodilatory response to Ach distal to the treated segments. Vasodilatory response after post-dilation with non-DCB was similar to control arteries.