Progressive stenosis of a popliteal artery stent graft by laminated thrombus

We present a case of failed popliteal artery aneurysm repair using a Viabahn stent graft (W. L. Gore & Associates, Flagstaff, Ariz) due to laminated thrombus formation. A 75-year-old man presented with a symptomatic popliteal artery aneurysm. He was treated with a Viabahn stent graft. On follow-up, the patient complained of lower extremity claudication, and duplex ultrasound examination showed a focal intrastent stenosis. A computed tomography scan showed a significant stenosis within the stent graft, at the level of the knee joint creases. The patient underwent superficial femoral artery to distal popliteal surgery. This case report aims to expand on the mechanism of stent graft failure in popliteal aneurysms

Outcome Benefit of Arterial Duplex Stent Imaging After Superficial Femoral Artery Stent Implantation

INTRODUCTION: In-stent stenosis is a frequent complication of superficial femoral artery (SFA) endovascular intervention and can lead to stent occlusion and/or symptom recurrence. Arterial duplex stent imaging can be used in the surveillance for recurrent stenosis, however, its uniform application is controversial. In this study, we aim to determine, in patients undergoing SFA stent implantation, whether surveillance with arterial duplex stent imaging yielded a better outcome than those with only ankle-brachial index (ABI) follow-up. METHODS: We performed a retrospective analysis of all patients undergoing SFA stent implantation for occlusive disease at a tertiary care referral center between 2009 and 2016. The patients were divided into those with arterial duplex stent imaging (ADSI group) and those with ankle brachial index follow-up only (ABI group). Life table analysis was performed, comparing stent patency, major adverse limb event, limb salvage, and mortality between groups. RESULTS: Two hundred forty-eight patients with SFA stent implantation were included: 160 into ADSI; 88 into ABI. Groups were homogenous regarding clinical indication (claudication/critical limb ischemia ADSI 39/61% vs ABI 38/62%; P = 0.982) and TASC classification (TASC A/B/C/D for ADSI 17/45/16/22% and ABI 21/43/16/20%; P = 0.874). Primary patency was similar between groups at 12/36/56 months: ADSI (65/43/32%) vs ABI (69/34/34%) (P = 0.770), whereas ADSI patients showed an improved assisted primary patency (84/68/54%) vs ABI (76/38/38%; P = 0.008) and secondary patency. There was a greater freedom from major adverse limb event in the ADSI group (91/76/64%) vs the ABI group (79/46/46%) (P \u3c 0.001) at 12/36/56 months follow-up. Arterial duplex stent imaging patients were more likely to undergo an endovascular procedure as their initial post-SFA stent implantation intervention (P = 0.001) whereas ABI patients were more likely to undergo an amputation (P \u3c 0.001). CONCLUSIONS: In SFA stent implantation, patients with arterial duplex stent imaging follow-up demonstrate an advantage in assisted-primary patency and secondary patency and are more likely to undergo an endovascular re-intervention. These factors likely effected a decrease in major adverse limb events, indicating the benefit of a more universal adoption of post-SFA stent implantation follow-up arterial duplex stent imaging

Long-term in vivo degradation behavior and near-implant distribution of resorbed elements for magnesium alloys WZ21 and ZX50

We report on the long-term effects of degrading magnesium implants on bone tissue in a growing rat skeleton using continuous in vivo micro-Computed Tomography, histological staining and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Two different magnesium alloys—one rapidly degrading (ZX50) and one slowly degrading (WZ21)—were used to evaluate the bone response and distribution of released Mg and Y ions in the femur of male Sprague-Dawley rats. Regardless of whether the alloy degrades rapidly or slowly, we found that bone recovers restitutio ad integrum after complete degradation of the magnesium implant. The degradation of the Mg alloys generates a significant increase in Mg concentration in the cortical bone near the remaining implant parts, but the Mg accumulation disappears after the implant degrades completely. The degradation of the Y-containing alloy WZ21 leads to Y enrichment in adjacent bone tissues and in newly formed bone inside the medullary space. Locally high Y concentrations suggest migration not only of Y ions but also of Y-containing intermetallic particles. However, after the full degradation of the implant the Y-enrichment disappears almost completely. Hydrogen gas formation and ion release during implant degradation did not harm bone regeneration in our samples.ISSN:1742-7061ISSN:1878-756