A novel unembalmed human cadaveric limb model for assessing conformational changes in self-expanding nitinol stents in the popliteal artery.

OBJECTIVE: To develop an unembalmed human cadaveric lower limb model as a more realistic environment for testing self-expanding nitinol stents. We studied conformational changes and strain induced by knee flexion in nitinol stents deployed in the popliteal artery (PA). METHODS: One Lifestent® each was deployed into one limb of four cadavers (control group), while the contralateral leg received a different stent (Absolute®, Protégé Everflex®, Supera®, and Gore Viabahn®). The limbs were mounted on a quasi-static knee rig (QKR) and X-ray imaging was performed at pre-defined knee flexion angles. A least-squares solution to the equation of a circle was used to assess radius of curvature at flexion points (FP), and nominal strain was calculated for each stented artery. RESULTS: There were differences but also some similarities in conformational changes seen in the various stents. Knee flexion produced at least two FP in all stents. The mean radius of curvature decreased with increasing degrees of flexion but more so in distal (main) than proximal (accessory) FP (22 mm vs. 11 mm) in all stents. Supera® stent had the greatest relative radii of curvatures, and Absolute® stent had the highest strain value in comparison to the contralateral PA as the control group. CONCLUSION: This study describes a novel human cadaveric limb model for testing self-expanding nitinol stents implanted in the PA. Several parameters of conformational change in the stented PA such as FP formation, FP translocation and strain induced by axial compression were described. These may be useful for developing new stents for the PA location.

A nationwide analysis of 30-day readmissions related to critical limb ischemia.

Objectives There is paucity of information regarding critical limb ischemia-related readmission rates in patients admitted with critical limb ischemia. We studied 30-day critical limb ischemia-related readmission rate, its predictors, and clinical outcomes using a nationwide real-world dataset. Methods We did a secondary analysis of the 2013 Nationwide Readmissions Database. We included all patients with a primary diagnosis of extremity rest pain, ulceration, and gangrene secondary to peripheral arterial disease. From this group, all patients readmitted with similar diagnosis within 30 days were recorded. Results Of the total 25,111 index hospitalization for critical limb ischemia, 1270 (5%) were readmitted with a primary diagnosis of critical limb ischemia within 30 days. The readmission rate was highest (9.5%) for the group that did not have any intervention (revascularization or major amputation) and was lowest for surgical revascularization and major amputation groups (2.6% and 1.3%, P value <0.001 for all groups). Severity of critical limb ischemia at index admission was associated with a significantly higher rate of 30-day readmission. Critical limb ischemia-related readmission was associated with a higher rate of major amputation (29.6% vs. 16.2%, P<0.001), a lower rate of any revascularization procedure (46% vs. 62.6%, P<0.001), and a higher likelihood of discharge to a skilled nursing facility (43.2% vs. 32.2%, P<0.001) compared to index hospitalization. Conclusions In patients with primary diagnosis of critical limb ischemia, 30-day critical limb ischemia-related readmission rate was affected by initial management strategy and the severity of critical limb ischemia. Readmission was associated with a significantly higher rate of amputation, increased length of stay, and a more frequent discharge to an alternate care facility than index admission and thus may serve as a useful quality of care metric in critical limb ischemia patients.

Progression of external and internal carotid artery stenosis is associated with a higher risk of ischemic neurologic events in patients with asymptomatic carotid artery stenosis.

A small percentage of patients with asymptomatic carotid artery stenosis (ACAS) who are on optimal medical management do go on to develop ischemic stroke or transient ischemic attacks (IS/TIA). Several diagnostic tools have been studied to identify those patients who are at increased risk. However, most of these diagnostic tools are not available for routine clinical use or are resource intensive. We performed a retrospective study to assess the incremental value of external carotid artery stenosis progression (ECASP) along with internal carotid artery stenosis progression (ICASP) in predicting risk of ipsilateral IS/TIA in a cohort of patients with ACAS. We conducted a retrospective analysis of patients with ACAS who had at least two serial duplex ultrasounds (DUS) at our center. A total of 356 patients (712 carotid arteries) were included in the study (mean age 74.7±9 years, 49.2% male) with a mean follow-up of 60.7±32.7 months. In univariate analysis, concurrent progression of ICA and ECA stenosis on the same side arteries was associated with a very significant increased risk of ipsilateral IS/TIA (14.7% vs 4.6%, p<0.001). Also, multivariable regression analysis showed that concurrent ECA/ICA progression was an independent predictor of IS/TIA (OR=3.6, 95% CI 1.64-7.8; p=0.001). ECASP along with ICASP is significantly associated with increased risk of ipsilateral IS/TIA and provides incremental risk stratification over that provided by ICASP alone. The ECA is routinely evaluated in clinical practice, and it could serve as an additional marker for identifying higher risk patients with ACAS.

Treatment of Angio-Seal® Vascular Closure Device-Induced Acute Femoral Artery Occlusion with SilverHawk® Directional Atherectomy.

Vascular closure devices provide a safe and cost-effective method to achieve rapid hemostasis and early ambulation after angiographic procedures. Rarely, they can result in arterial injury with resultant stenosis or acute arterial closure requiring open surgical intervention. We report an Angio-Seal® vascular closure device-induced acute arterial closure successfully treated percutaneously with the SilverHawk® plaque excision system. This report discusses the possible mechanisms of Angio-Seal® induced arterial occlusion and various percutaneous options for treatment.

Percutaneous treatment of severe diffuse stenosis in heavily calcified infrarenal abdominal aorta using iliac extender endoprosthesis: a case series.

Severe, concentric calcific stenosis of the infrarenal abdominal aorta (IAA) is an uncommon but technically challenging problem. In diffuse, heavily calcific lesions are generally not treated with balloon expandable or self-expanding stents. There is concern of aortic rupture, incomplete apposition, and underexpansion. Such lesions are mostly treated with aortobifemoral or extra-anatomic bypass surgery. Using three case examples, we describe the feasibility of endovascular treatment for severely calcific IAA with use of iliac extender limbs of commercially available aortic stent grafts and discuss the role of preprocedural CT scan in case planning.