bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of vehicle suspension using an adaptive inerter
Authors: Li Panshuo , Lam James , Cheung Kie Chung
Published: March 2015

In this paper, we study the suspension performances with an adaptive inerter under the assumption that the inertance may be adjusted in real-time. A quarter-car model with an inerter installed in parallel with a spring and a damper is considered. First, for a given suspension system, a study of the effects of using a fixed inerter is provided. It shows the difficulty in choosing a fixed inerter to satisfy the vehicle performances at the sprung mass natural frequency without deteriorating significantly at the unsprung mass natural frequency. Then, a state-feedback H2 controller for an active suspension system is designed. The active force is approximated by an inerter with adjustable inertance. Ride quality, suspension deflection and tyre deflection performances are considered independently as the prime objective. Simulation results show that comparing with the passive suspension with fixed inerter, for ride quality and tyre deflection, the suspension with adaptive inerter can achieve improvement at the sprung mass natural frequency at the expense of a relatively small deterioration at the unsprung mass natural frequency. For suspension deflection, a better performance can be achieved at high frequencies with almost no loss of performance at other frequencies. This method is easier to implement in practice than the optimized passive suspension with a fixed inerter, which calls for complicated layout.
Robust fault-tolerant tracking control for a class of nonlinear systems based on position measurements only
Authors: Shen Gang , Zhu Zhen-Cai , Li Xiang , Meng Qiang , Tang Yu , Li Wei , Liu Shan-Zeng
Published: March 2015

The problem of trajectory tracking for a class of nonlinear systems in the presence of un-modeled dynamics, parameter variations and even the actuator faults is investigated in this paper. A novel fault-tolerant control scheme is proposed by combining the nominal model-based controller and time-delay controller, which are adopted to achieve the real-time dynamic compensation and guarantee the robust stability of the controlled systems, respectively. Moreover, high-quality differential signals are unavailable in the presence of disturbances and measurement noise, which limit the performance of closed-loop systems in practice. Therefore, an extended state observer (ESO) is introduced to obtain high-quality differential signal estimations based on position measurements only. Furthermore, the effectiveness of the proposed novel control scheme is verified by testing in the spacecraft attitude tracking system.
Cognitive Dissonance as an Effect of Indulging on Credit
Authors: Dugar Anurag , Shreshtha Mani , Jain Rishabh
Published: March 2015

Indians are known to have high regard for savings, thanks to the age-old pro-saving lessons that are part of the Indian DNA. Till recently, this deep-rooted pro-savings attitude made sure that Indian consumers were uncomfortable with the idea of indulging, and indulging on credit has been a taboo. However, changing lifestyles and exposure to the glamour and thrill of spending are unfastening this grip. If numbers of “active card holders” and “usage of credit” are any indicator, than Indians have started accepting credit as a way of life.

Most of the research work carried out on the subject is restricted to “usage patterns” in different markets and impact of demographic factors and lifestyle on acceptance and usage of credit cards. This study is aimed at finding insights on whether consumers feel that credit cards encourage them to indulge and post-spending there is a higher level of cognitive dissonance. Data, for this study, have been collected from upper-middle-class urban consumers and analyzed through statistical tools to figure out the answers to these questions.

This study can be of immense use for credit card marketers as they can figure out if they have to reduce the cognitive dissonance of the consumers of their credit cards and they will also figure out whether brand positioning based on symbolic benefits would be advantageous or utilitarian value that the brand offers.
Enterprise as a Social System
Authors: Oleksyn Tadeusz
Published: March 2015

An enterprise in satisfying defined social needs and sustaining its position creates a specific social system and is simultaneously submerged in the broader social system in which it operates. Without both of these systems—the internal and the external ones—it could neither exist nor do anything. It is therefore possible to distinguish out of different notions and models of enterprises the model of enterprises perceived as a social system.

This article aims at reflection on this very system and model. It reviews select issues associated with this theme. The purpose is to inspire reflections and to raise questions on the role of enterpsises at an interdisciplinary level.
An Empirical Test of Market Efficiency of Indian Index Options Market Using the Black–Scholes Model and Dynamic Hedging Strategy
Authors: Mohanti Debaditya , Priyan P. K.
Published: March 2015

The purpose of the present study is to provide evidence on the market efficiency of the S&P CNX Nifty index options traded on the National Stock Exchange (NSE) of India, using the Black–Scholes model and dynamic hedging strategy. Till today, a limited literature exists on the market efficiency of the Indian index option by using a dynamic hedging strategy. Thus, an effort has been made in constructing the dynamic hedging strategy to examine whether the violations obtained from the Black–Scholes model can be covered by the costs in setting up the dynamic hedge strategy. The data collected in this study consist of daily closing prices of S&P CNX Nifty index options contracts from 1 April 2008 to 31 March 2012. The results demonstrate that, although the sensitivity analysis of violations with respect to liquidity, time to maturity and moneyness show that the majority of violations in options are exploitable, the proportion of exploitable violations severely falls after considering the transaction cost, as most of the profits were wiped out and showing negative profits. Thus, although the Indian index options market shows traces of inefficiency, in totality, it is suggested that the Indian index options market is efficient as a majority of violations are un-exploitable after incorporating transaction cost.
Translating and Transforming Care
Authors: Gillespie Alex , Moore Helen
Published: March 2015

This article examines how the Disability Living Allowance claim form, used in the United Kingdom to allocate £13 billion of disability benefits, translates and transforms disability and care. Twenty-two people with acquired brain injury and their main informal caregivers ( n = 44) were video-recorded filling in the disability claim form. Participants disagreed on 26% of the questions, revealing two types of problems. Translation problems arose as participants struggled to provide categorical responses to ambiguous questions and were unable to report contextual variability in care needs or divergences of perception. Transformation problems arose as participants resisted the way in which the form positioned them, forcing them to conceptualize their relationship in terms of dependency and burden. The disability claim form co-opts claimants to translate care and disability into bureaucratically predefined categories, and it transforms the care relationship that it purports to document.
Turnout as Consent
Authors: Miles Matthew R.
Published: March 2015

The dominant view assumes that people vote to influence election outcomes. As such, most assume that campaign contact, election competitiveness, and the probability of one’s voting influencing the outcome of an election are the primary forces motivating voter participation. However, some people may view elections as a referendum on system performance and may participate in elections regardless of the electoral outcome. Voting is one means for the public to express their consent to be governed. If so, we should expect higher voter participation in systems that generate public approbation. This article uses a national survey experiment, a cross-national panel of thirty-five advanced democracies, and aggregate voter turnout data to demonstrate that people in systems that control corruption, govern effectively, and have fair judicial processes are more likely to vote. This is because systems that treat people fairly in their day-to-day operations make people feel valued by their political system. Particularly when the probability of changing the composition of government with a single vote is small, voting is a tacit endorsement of the existing regime.
Samuel T. Gladding
Authors: Donovan Kimberly A. , Weigel Daniel J.
Published: March 2015

Samuel Templeman Gladding has established himself as a creative voice and a pillar in the field of marriage, couple, and family (MCF) counseling. In doing so, Dr. Gladding has served the counseling profession, most notably in the specialty of MCF counseling, in a variety of inspiring and innovative ways. The purpose of this article is to summarize the significance of Dr. Gladding’s continuing legacy in the field of MCF counseling by reviewing his many contributions to the profession and by sharing his responses from a recently conducted interview exploring his perspectives on historical and contemporary issues affecting the profession of MCF counseling.
Muscle temperature at the point of filleting—Subsequent effect on storage quality of prerigor filleted raw- and cold-smoked Atlantic salmon
Authors: Lerfall Jørgen , Rotabakk Bjørn Tore
Published: March 2015

The impact of increased muscle temperature at the point of filleting on fillet quality of raw- and cold-smoked Atlantic salmon was investigated. Commercially reared fish (5.65 kg, Kf: 1.23, pH: 7.29, muscle temperature: 6.68 ℃) were killed and immediately tempered in three different containers. Muscle temperatures after filleting (<3 h postmortem) of the three groups were 2.08 ℃ (hereafter named T-2); 9.07 ℃ (hereafter named T-9), and 14.09 ℃ (hereafter named T-14), respectively. The pH after filleting was significantly low for T-14 (6.93) followed by T-9 (7.06) and T-2 (7.22). Raised temperature at point of filleting was found to significantly alter development of rigor mortis, which subsequently affected muscle pH and the reflective properties of the fillet surface during 14 days' ice storage. Of cold-smoked fillets, however, a more distinct effect of raised temperature was observed on visual perception resulting in lighter and more yellowish cold-smoked fillets after 14 days' storage. In addition, raised temperature also affects the development of muscle pH in cold-smoked fillets during refrigerated storage. No effects of raised muscle temperature were found regarding drip loss, water-holding capacity, or fillet firmness either for raw- or cold-smoked fillets throughout the storage period.
The Effects of Discussion and Information on Public Support for Tax and Fee Increases for Transportation
Authors: Yusuf Juita-Elena (Wie) , O’Connell Lenahan
Published: March 2015

This research note compares the effect on willingness to raise taxes and government fees of three common approaches to public consultation: (a) a telephone survey with no information or discussion, (b) a focus group with discussion but no information relating need to the proposed tax or fee, and (c) a focus group with discussion and such information. Our purpose is twofold: (a) illustrate the contribution of pertinent information to public acceptance of tax or fee increases, and (b) suggest a more comprehensive and informative approach to consultation with the public. We do so using the examples of raising the gas tax and vehicle registration fees. The results show that the combination of information and discussion produces the greatest level of support for both revenue enhancing options. Implications for presenting proposals to raise taxes and fees are discussed.
Parametric study on static and dynamic characteristics of bump-type gas foil thrust bearing for oil-free turbomachinery
Authors: Feng Kai , Liu Liang-Jun , Guo Zhi-Yang , Zhao Xue-Yuan
Published: March 2015

Gas foil bearings have bright application prospects in oil-free turbomachinery such as aircraft air cycle machines, compressors, and gas turbines. To extend the applicability of foil bearings to high-speed and heavy-load systems, the axial force produced primarily by the pressure difference between the turbine and compressor sides must be taken into consideration. The thrust disc of the rotor is typically used to sustain the axial force and maintain the attitude of the rotor in a rotor-bearing system. In an analytical model used to predict the performance of gas foil thrust bearings, fluid–structure interaction must be considered because of the coupling effects of hydrodynamic lubrication and the compliance of bearing surface. In this study, a link-spring structural model was employed to calculate the equivalent vertical stiffness of the bump foil. This model exhaustively considered the effect of three factors: flexibility of the bump foil, interactions between bumps and frictional forces at the contact surfaces. In addition, top foil deflection that directly affects film thickness is calculated using a finite-element shell model. The static and dynamic characteristics of gas foil thrust bearings were predicted after solving the steady-state Reynolds equation and two linearized dynamic coefficient equations which were obtained with perturbation method by using finite-difference method. The structural deformation equation was substituted into the Reynolds equations in the calculation process. The calculated static load was compared with the published experimental data, and the results validated the theoretical analysis. Thereafter, the static and dynamic characteristics including impact of rotational speed, initial minimum film thickness and the ratio of the inlet to outlet film thicknesses were analyzed. Parametric studies were also conducted to evaluate the effect of different structural parameters of the bump foil and journal tilting on the static characteristics of gas foil thrust bearings. Because the proposed analytical model is completely algebraic, it can be easily programmed for accurately and effectively investigating the performance of gas foil thrust bearings.
‘A good Irishman should blush every time he sees a penny’: Gender, nationalism and memory in Irish internment camp craftwork, 1916–1923
Authors: Brück Joanna
Published: March 2015

This article explores how the craftwork created in Irish prisons and internment camps in the aftermath of the 1916 Rising through to the end of the Civil War allowed prisoners to negotiate changing concepts of political and social identity. Items such as bone crosses and harps reveal the tensions inherent in discourses of religious identity and cultural nationalism, while the reworking of prison-issue objects illustrates how a sense of personal agency was maintained in a profoundly disempowering context. Macramé handbags and children’s reins gave internees a continued sense of involvement in and control over their homes and relationships, while mantle borders, tea cosies and table centres conjured idealised notions of domesticity. Fundamentally, the creation of such objects allowed prisoners to engage with the troubling and often contradictory experiences of masculinity that lay at the heart of camp life.
The European Commission and the implementation of its legislative programme
Authors: Osnabrügge Moritz
Published: March 2015

This article analyses the circumstances under which the European Commission implements its legislative programme on time. Similar to many national governments the European Commission announces an annual Work Programme, where it identifies important legislation it plans to propose within 12 or 18 months. This study is based on an original dataset of 233 legislative proposals listed in the Work Programme in the period 2005–2012. I show that the Commission implements at least 94% of its legislative programme, where 76% of the proposed legislation is formally introduced within the deadline. The empirical analysis provides evidence that procedural and technical complexity decreases the probability of timely implementation. In addition, proposals listed in Work Programmes that allow for the introduction of some proposals within the extended deadline of 18 months are more likely to be introduced on time. The size of the gridlock interval, as defined in spatial models, does not have a statistically significant effect.
Transcranial Doppler Monitoring in Angioplasty and Stenting of the Carotid Bifurcation
Authors: Ackerstaff R.G.A. ,   Antonius Carotid Endarterectomy, Angioplasty, and Stenting Study Group
Published: March 2015

Purpose:

To assess the impact of cerebral embolism and hemodynamic changes during the successive stages of carotid angioplasty and stenting (CAS) using transcranial Doppler (TCD) monitoring of the middle cerebral artery (MCA).

Methods:

In 297 patients (206 men; mean age 69.9±8.0 years), the association of various TCD emboli and velocity variables with procedure-related death and cerebral events (amaurosis fugax, transient ischemic attacks, and stroke) was evaluated. Baseline patient characteristics (age, sex, preoperative cerebral symptoms, and prior carotid endarterectomy) and their associations with procedure-related cerebral events were also assessed. A distinction was made between adverse events that occurred during CAS and those that happened within 7 days.

Results:

Of the 36 procedure-related retinal and cerebral events, 28 (78%) were encountered intraprocedurally; an additional 6 (2%) events occurred within 7 days after the procedure. Two (0.7%) patients died. At 1 week, the combined minor and major stroke and death rate was 3.7%. Adverse outcome was associated with >4 showers of microemboli at postdilation (odds ratio [OR] 3.2, 95% CI 1.3 to 7.8, p = 0.03), particulate macroemboli (OR 9.1, 95% CI 5.1 to 16.1, p<.001), massive air embolism from ruptured balloons (OR 11.3, 95% CI 7.6 to 16.6, p<0.001), and angioplasty-induced asystole with significant hypotension plus MCA blood flow reduction (OR 3.3, 95% CI 1.4 to 8.3, p = 0.03). Of the patient characteristics, male gender (OR 10.5, 95% CI 1.4 to 75.8, p = 0.02) and preoperative cerebral ischemia (OR 3.3, 95% CI 1.6 to 6.6, p = 0.003) were also related to outcome.

Conclusions:

In CAS, TCD monitoring provides insight into the pathogenesis of procedure-related cerebral events. Microemboli during poststent dilation, particulate macroembolism, massive air embolism, and angioplasty-induced asystole are associated with adverse outcome, as are male gender and prior cerebral ischemia.
Treatment of Axillosubclavian Vein Thrombosis: A Novel Technique for Rapid Removal of Clot Using Low-Dose Thrombolysis
Authors: Arko Frank R. , Cipriano Paul , Lee Eugene , Filis Konstantinos A. , Zarins Christopher K. , Fogarty Thomas J.
Published: March 2015

Purpose:

To report successful combined percutaneous mechanical thrombectomy and pharmacological lysis for axillosubclavian vein thrombosis, with rapid clot removal at a single setting using low-dose thrombolysis.

Case Reports:

Two consecutive patients presented with arm swelling; the diagnosis of axillosubclavian vein thrombosis was confirmed with duplex ultrasound. Both patients were treated percutaneously with the Solera mechanical thrombectomy device, after which 5 mg of tissue plasminogen activator were delivered within ∼10 minutes via the Trellis infusion catheter to remove any residual thrombus. Completion venography and serial duplex ultrasound scans in follow-up demonstrated widely patent axillosubclavian veins with no residual thrombus in both cases.

Conclusions:

Standard treatment of axillosubclavian vein thrombosis may require 12 to 36 hours, with multiple trips to the angiography suite. The novel technique combining mechanical thrombectomy and pharmacological lysis can be performed safely and successfully at a single setting with a small dose of the lytic drug.
Percutaneous Modular Stent-Grafts in the Treatment of Abdominal Aortic Aneurysms
Authors: Lee Do Yun , Kang Sung-Gwon , Choi Donghoon , Lee Gwang Hoon , Maeda Munehiro , Roh Byung Suk , Won Jae Whan , Kim Chang Won , Kim Eun Sang , Song Ho-Young
Published: March 2015

Purpose:

To describe a newly designed bifurcated modular stent-graft and assess the feasibility and safety of its use in the treatment of abdominal aortic aneurysms (AAA).

Methods:

Thirteen patients (10 men; mean age 61.2±16 years, range 57–78) with AAAs underwent treatment with a bifurcated stent-graft consisting of 4 components: an unsupported bifurcated stent-graft, an inner bare stent, and 2 stent-grafts. The system was placed sequentially through a percutaneously introduced 12-F sheath; the preloaded bifurcated main body of the stent-graft was deployed first, followed by the inner bare stent and individual stent-graft limbs through separate 10-F sheaths. Spiral computed tomography (CT) was performed before treatment and at 1 week, 3 months, and then at 6-month intervals.

Results:

The stent-grafts were successfully deployed in all patients, although 3 types of procedure-related adverse events occurred: left limb kinking in 1, postimplantation syndrome (fever, leukocytosis, and decreased platelet count) in 5, and a small access site arteriovenous fistula in 1. Postprocedural angiography and 1-week follow-up CT scanning did not identify any endoleaks. At a mean 9.2±4.6-month follow-up, all devices were intact, with complete exclusion of the aneurysms and no endoleaks.

Conclusions:

This newly designed bifurcated modular stent-graft appears to be effective for percutaneous AAA repair; further investigation is warranted.
Endotension in the Closed Aneurysm Sac during Aortic and Iliac Cross Clamping: Implications of Pressure and Flow Measurements
Authors: Gawenda Michael , Brunkwall Jan
Published: March 2015

Purpose:

To relate the mean and pulse pressures in the cross-clamped aortic aneurysm sac to the systemic pressures during open repair (OR) of abdominal aortic aneurysm (AAA). To correlate the intrasac pressures to the number of bleeding lumbar arteries (LA) and the flow pattern of the inferior mesenteric artery (IMA).

Methods:

In a prospective study of 55 patients (45 men; median age 69 years, range 47–84) undergoing open repair, the IMA flow and the mean pressure in the aneurysm sac (ASPmean) were measured before and after aortic and iliac artery cross clamping. The systemic mean pressure (SPmean) was recorded simultaneously. The aneurysm sac (ASPpulse) and systemic pulse pressures (SPpulse) were calculated, as were the mean pressure ratio (ASPmean/SPmean) and the pulse pressure ratio (ASPpulse/SPpulse). Values are given as the median (range).

Results:

Cross clamping of the proximal aortic neck significantly reduced the mean pressure to 31 mmHg (14–64), with a pressure ratio of 0.39±0.14; the pulse pressure decreased to 0 mmHg (0–13) (p<0.001). Additional cross clamping of the iliac arteries did not alter the pressure levels any further. In the patent IMA (n = 23), an orthograde median flow of 43 mL/min (2–135) was measured; sequential cross clamping of the aorta and iliac arteries reduced the flow to −6 mL/min (–130 to +21) and −3 mL/min (–120 to +22), respectively. There was no correlation between the pressure ratio and IMA patency, its volume flow, or the number of backbleeding lumbar arteries.

Conclusions:

The aneurysm sac is still pressurized with no pulsatility after cross clamping during open AAA repair. The aneurysm mean and pulse pressures did not correlate to the number of backbleeding lumbar arteries. Finally, the pressure ratios did not correlate to the highly variable IMA flow pattern during aortic cross clamping.
Clinical Experience with the OptiMed Sinus Stent in the Peripheral Arteries
Authors: Henry Michel , Henry Isabelle , Klonaris Christos , Hugel Michele
Published: March 2015

Purpose:

To retrospectively evaluate the performance of a new self-expanding nitinol stent in the treatment of lower limb arterial occlusive lesions.

Methods:

The Sinus stent is a flexible, laser-cut device with good radiopacity and radial strength, allowing precise placement via a 7-F introducer, even in tortuous arteries. Over a 3.5-year period, 315 patients (254 men; mean age 64.9±10.8 years, range 39–93) had 403 lower limb lesions treated: 172 iliac (132 stenoses, 40 occlusions), 204 femoral (131 stenoses, 73 occlusions), and 27 popliteal (19 stenoses, 8 occlusions). The majority of patients (272, 86%) were in stage IIb of Fontaine's classification, 31 (10%) in stage III, and 12 (4%) in stage IV. Mean lesion lengths were iliac: 51.9±32.1 mm, femoral: 66.3±51.5 mm, and popliteal: 44.3±27.2 mm. Indications for stenting were 222 postdilation residual stenoses, 125 dissections, and 35 restenoses; 21 lesions were directly stented.

Results:

Immediate technical success was 100%. Clinical success was 98%. The anklebrachial index increased from 0.62±0.12 to 0.91 ±0.14. In 64 lesions, there were 3 early thromboses. Mean follow-up was 16.1 ±9.7 months (range to 40). There were 79 restenotic episodes: 14 iliac, 56 femoral, and 9 popliteal. Primary and secondary patencies for all lesions at 3 years were 72.5%±6.6% and 81.8%±5.9%, respectively. Stenoses demonstrated better patency than occlusions (primary: 78.0%±7.3% versus 60.2%±7.1%, p<0.001; secondary: 86.8%±6.1% versus 71.3%±6.7%, p<0.001). Men had better secondary patency at 3 years (83.7% versus 73.4%, p<0.05). For femoral lesions >8 cm, the results were acceptable for stenoses (66.7% primary and secondary patency at 3 years), but for lengthy occlusions, the restenosis rate was high (50.0% for occlusions versus 25.0% for stenoses, p<0.05).

Conclusions:

Angioplasty with the Sinus stent seems safe and effective in the treatment of peripheral arterial occlusive diseases, giving excellent results at the iliac and common femoral artery levels. Treatment results are better for stenoses than for occlusions. An occlusion length ≤8 cm seems to be the limit for stenting.
The “Y” Stent: A Technique Using Nitinol Stents to Treat Bifurcations
Authors: Sze Daniel Y. , Razavi Mahmood K. , Mitri Ragheed K. , Regala Alan C. , Dake Michael D.
Published: March 2015

Purpose:

To investigate a new method of stent deployment using commercially available self-expanding stents to treat bifurcation lesions, providing complete lesion coverage without obstructing branches.

Methods:

After preliminary in vitro and clinical testing with biliary obstructions, 11 vascular obstructive lesions in 10 patients (7 men; mean age 63 years, range 32–81) were treated by percutaneous Y-shaped stenting. Five patients had iliac arterial stenoses involving the iliac bifurcation; the other 5 patients had 6 central venous obstructions involving branch points. Bifurcated stents were constructed in situ by deploying a nitinol stent extending into one branch and selective balloon fracturing of struts to create a fenestration. A second stent was deployed through the hole, followed by symmetrical fracturing of struts in the second stent to form a Y-shaped configuration.

Results:

All deployments were technically successful and resulted in complete coverage of the bifurcation lesions. Protrusion of fractured stent material into flow lumens was minor as determined by angiography, intravascular ultrasound, and passage of balloons, but it required the stents to be oversized. The lengths and luminal diameters were tailored for each arm of the Y-shaped stents.

Conclusions:

In situ creation of a Y-shaped stent using 2 self-expanding nitinol stents is a feasible option with potential advantages in the treatment of obstructive lesions involving a bifurcation.
Transient Ischemic Attack Due to Early Carotid Stent Thrombosis: Successful Rescue with Rheolytic Thrombectomy and Systemic Abciximab
Authors: Bush Ruth L. , Bhama Jay K. , Lin Peter H. , Lumsden Alan B.
Published: March 2015

Purpose:

To describe a successful neurorescue technique in a patient with generalized seizures followed by hemiparesis immediately after carotid artery stenting (CAS) for a postsurgical restenosis.

Case Report:

A 65-year-old man with a symptomatic recurrent high-grade carotid stenosis after carotid endarterectomy was treated with CAS. The procedure was complicated by sudden transient ischemic attack caused by acute carotid stent thrombosis with clot propagation into the cerebral circulation. Percutaneous mechanical thrombectomy was performed with adjunctive infusion of intravenous abciximab, resulting in complete thrombus dissolution and resolution of neurological symptoms.

Conclusions:

Access to a mechanical thrombectomy device was essential for rapid thrombus extraction, and adjunctive abciximab aided in residual clot dissolution. As a result of this combined method of clot removal, a disastrous outcome was averted.
Follow-up after Endovascular Aortic Aneurysm Repair: The Plain Radiograph Has an Essential Role in Surveillance
Authors: Fearn Shirley , Lawrence-Brown Michael M.D. , Semmens James B. , Hartley David
Published: March 2015

Periodic follow-up is mandatory for patients with aortic stent-grafts. Central to surveillance is the establishment of a baseline against which changes can be detected. Computed tomography (CT) has been the benchmark of follow-up imaging for endografts, but comparison of serial AP and lateral plain radiographs will detect structural alterations that can be missed on CT scans. In this review, we illustrate these common endograft complications and the value of plain radiographs in their detection. We believe that the plain radiograph should be the cornerstone of aortic endograft surveillance. However, a standardized protocol should be used to avoid parallax and positioning errors that affect interpretation.
Frequency, Predictive Factors, and Consequences of Stent-Graft Kink following Endovascular AAA Repair
Authors: Fransen Gerdine A.J. , Desgranges Pascal , Laheij Robert J.F. , Harris Peter L. , Becquemin Jean-Pierre
Published: March 2015

Purpose:

To determine from the EUROSTAR registry the incidence of stent-graft kink, predictive factors for kinking, and the consequences of this complication on graft patency and aneurysm exclusion.

Methods:

From January 1994 to June 2002, 4613 patients who underwent endovascular aneurysm repair were registered in the EUROSTAR registry. Presence of kink was determined according to the information available on the follow-up Case Record Form. The population was divided into those with and without stent-graft kink. Patient characteristics, morphological aneurysm features, team experience, type of device, period of implantation, and outcome were compared between the groups by univariate analysis. Significant factors were subsequently submitted to a multivariate Cox proportional hazard analysis.

Results:

One hundred seventy (3.7%) patients were reported as having a kink of the stent-graft during a mean follow-up of 21 months (range 1–72). Gender, neck angulation, team experience, period of implantation, ASA classification, and device type were independent predictors of kink. The presence of a kink was significantly associated with type I endoleaks (proximal and distal), type III endoleaks (midgraft), graft stenosis, graft limb thrombosis, graft migration, and conversion to open repair. No relationship was found between a decrease in the aneurysm diameter and the occurrence of stent-graft kink.

Conclusions:

Kinks of stent-grafts were infrequent events in the intermediate term. Patients most at risk were women with angulated aortic necks treated by a minimally experienced team. Kinks are potentially damaging events because they may lead to delayed device-related endoleaks, graft stenosis, thrombosis, and conversion to open repair. They appear more closely associated to graft migration than to aneurysm diameter reduction.
Endovascular Stent-Graft Repair of a Complicated Penetrating Ulcer of the Descending Thoracic Aorta: A Word of Caution
Authors: D'Ancona Giuseppe , Bauset Richard , Normand Jean-Pierre , Turcotte Roc , Dagenais François
Published: March 2015

Purpose:

To report a pitfall encountered during stenting of a complicated penetrating ulcer of the descending thoracic aorta.

Case Report:

A 65-year-old man was diagnosed with a complicated penetrating ulcer of the thoracic aorta. A 38-mm Talent endograft was implanted. On balloon dilation of the distal end of the endoprosthesis, the terminal bare stent became distorted and penetrated the aortic wall. A 42-mm endoprosthesis was immediately placed to exclude the aortic perforation. Control aortography demonstrated exclusion of the original proximal aortic ulcer and the distal iatrogenic aortic tear.

Conclusions:

Endoprostheses may present some drawbacks in terms of elasticity and adaptability to tortuous and angulated diseased aortas. Caution is advised in the treatment of penetrating aortic ulcers where the aortic wall is diffusely friable. In this condition, balloon dilation should be limited to the covered portion of the stent-graft to prevent stent distortion and erosion through the aortic wall.
Endoluminal Repair of a Thoracic Arch Aneurysm Using a Scallop-Edged Stent-Graft
Authors: Kruger Allan J. , Holden Andrew H. , Hill Andrew A.
Published: March 2015

Purpose:

To report a new technique of endoluminal thoracic aortic arch aneurysm repair using a scalloped stent-graft.

Case Report:

A 79-year-old man presented with a 7.5-cm thoracic aneurysm involving the inner curve of the aortic arch. Endoluminal repair was performed with a scalloped stent-graft that allowed perfusion of the brachiocephalic (innominate) artery. Preliminary extra-anatomical left common carotid and subclavian artery bypass grafting had been performed to allow coverage of the origins of these vessels.

Conclusions:

The use of fenestrated endoluminal grafts in the aortic arch can be achieved safely and may increase the treatment options for the high-risk patient.
Development of a Branched Stent-Graft for Endovascular Repair of Aortic Arch Aneurysms
Authors: Chuter Timothy A.M. , Buck David G. , Schneider Darren B. , Reilly Linda M. , Messina Louis M.
Published: March 2015

Purpose:

To develop a branched stent-graft for endovascular repair of aortic arch aneurysm.

Methods:

Four different prototypes of a branched aortic stent-graft were inserted into a rubber model of the human aortic arch under fluoroscopic guidance. Each prototype was tested, modified, and tested again through a series of 4 iterations. The first 3 prototypes had multiple short side branches, as docking sites for extensions into the branches of the aortic arch. The last iteration had only 1 short branch for an extension into the distal aorta and 1 long branch for direct perfusion of the innominate artery.

Results:

With every re-design, the prototype aortic stent-graft became shorter, and its insertion site moved to a more proximally located arch artery. Stent-graft insertion, orientation, and extension also became quicker and easier with each change in device design. However, the only system to perform reliably was the last, which was subsequently used to treat a large, symptomatic pseudoaneurysm of the aortic arch in a high-risk patient.

Conclusions:

None of our multibranched systems was simple, safe, or durable enough for insertion into the aortic arch; only an iteration that had a short branch for an extension into the distal aorta and a long branch for direct perfusion of the innominate artery could be deployed without difficulty or delay.
Technological Advances in the Design of Catheters and Devices Used in Renal Artery Interventions: Impact on Complications
Authors: Zeller Thomas , Frank Ulrich , Müller Christian , Bürgelin Karlheinz , Schwarzwälder Uwe , Sinn Lutz , Horn Barbara , Roskamm Helmut , Neumann Franz-Josef
Published: March 2015

Purpose:

To analyze the impact of technical improvements in stent devices and guiding catheters (e.g., reduced device diameter, increased flexibility) on the complication rates associated with percutaneous renal artery interventions.

Methods:

During a 5-year period (1997–2001), 268 consecutive patients (178 men; mean age 67±9 years) had 370 atherosclerotic renal artery stenoses (RAS) ≥70% treated with angioplasty/stenting in 320 procedures. The guiding catheter technique was used routinely until 2000; in 2001, a guiding sheath was used in 29% of cases. From 1997 to 2000, sealing devices were frequently used for sheath removal; during the last year, the sheaths were removed using the Femostop device.

Results:

In 320 interventions, 32 (10%) complications occurred, with a decreasing frequency during the last 2 years (1996/97: 13% [7/53]; 1998: 16% [9/57]; 1999: 15% [11/74]; 2000: 4% [3/70]; 2001: 3% [2/66]). There were 21 (6.6%) local complications, including 4 cases requiring permanent hemodialysis after the intervention and 11 (3.4%) access site complications. No procedure-related death occurred. During the study period, the average sheath diameter was reduced from 8.15±0.76 F to 6.15±0.63 F (p<0.05). Mean procedural time was reduced from 42±13 minutes to 23±11 minutes (p<0.05). The initial heparin dose was reduced from 10,000 to 5000 units.

Conclusions:

In parallel with the use of more flexible catheters and premounted stents of lower profile, the complication rate of renal angioplasty/stenting of atherosclerotic RAS has been reduced significantly during a 5-year period.
Carotid Revascularization Using Endarterectomy or Stenting Systems (CARESS): Phase I Clinical Trial
Authors: McKinlay Sonja ,   CARESS Steering Committee
Published: March 2015

Purpose:

To determine whether carotid stenting with embolic protection is equivalent to carotid endarterectomy (CEA) in a broad risk population of patients with symptomatic and asymptomatic carotid stenosis.

Methods:

A prospective, multicenter Phase I trial was conducted comparing standard CEA to carotid stenting systems (CSS) in patients with symptomatic (≥50%) and asymptomatic (≥75%) carotid stenosis. Patients were enrolled using selection criteria reflective of broad clinical practice. The enrollment ratio at each clinical site was designed to be 2:1 (CEA to CSS) to achieve a planned enrollment of 450 patients: 300 in the CEA arm and 150 in the CSS cohort, which would ensure adequate precision with a coefficient of variation ≤0.35. The primary endpoint for comparison was 30-day all-cause mortality and nonfatal stroke.

Results:

Between April 2001 and December 2002, 14 clinical sites enrolled 439 patients, of which 397 (247 men; mean age 71 years, range 44–89) were treated: 254 with CEA and 143 patients with CSS (ratio 1.8 to 1.0). More than 90% of patients had >75% stenosis; ∼68% of patients were asymptomatic. There were no significant differences in baseline patient characteristics between the treatment groups with the exception of a more frequent history of prior CEA (30% CSS versus 11% for CEA, p<0.0001) and prior carotid stent placement in the CSS group (6% versus 0% for CEA, p = 0.0002). There was no significant difference in the 30-day combined all-cause mortality and stroke rate by Kaplan-Meier estimate between CEA (2%) and CSS (2%). There was no significant difference in the secondary endpoint of combined 30-day all-cause mortality, stroke, and myocardial infarction between CEA (3%) and CSS (2%).

Conclusions:

This study suggests that the 30-day risk of stroke or death following carotid stenting with cerebral protection is equivalent to standard carotid endarterectomy in a broad risk population of patients with carotid stenosis.
Filter Devices for Cerebral Protection during Carotid Angioplasty and Stenting
Authors: Kasirajan Karthikeshwar , Schneider Peter A. , Kent K. Craig
Published: March 2015

The risk of embolization during carotid artery stenting (CAS) has been the foremost reason for the cautious acceptance of this percutaneous alternative to carotid endarterectomy. To address this issue, numerous embolic protection devices are being evaluated as an adjunct to CAS for neuroprotection. Among the 3 main categories of these devices, distal filters, which trap embolic debris while maintaining distal cerebral perfusion, have attracted the most corporate interest. This review focuses on the emerging field of embolic protection filters for use in CAS.
Angioplasty/Stenting of the Superior Mesenteric Artery and Celiac Trunk: Early and Late Outcomes
Authors: AbuRahma Ali F. , Stone Patrick A. , Bates Mark C. , Welch Christine A.
Published: March 2015

Purpose:

To analyze the early results and durability of angioplasty/stenting of the superior mesenteric artery (SMA) and celiac trunk (CT).

Methods:

Twenty-two patients (19 women; mean age 69.2 years, range 52–88) with 24 symptomatic SMA or CT stenotic lesions were treated with dilation/stenting over a recent 4.5-year period. Two patients had lesions in both the SMA and CT treated. Clinical follow-up and duplex exams were done to evaluate long-term patency. Kaplan-Meier life-table analyses estimated the freedom from recurrent stenosis and recurrent symptoms, as well as survival rates.

Results:

The initial technical and clinical success rates were 96% (23/24) and 95% (21/22), respectively, with no perioperative mortality or major morbidity. During a mean follow-up of 26 months (range 1–54), the primary late clinical success rate was 61% (11/18; 4 lost to follow-up), and freedom from recurrent stenosis (≥70%) was 30% (6/20). The freedom from recurrent stenosis at 1, 2, 3, and 4 years were 65%, 47%, 39%, and 13%; freedom from recurrent symptoms was 67% at all 4 intervals. The survival rates were 93%, 93%, 80%, and 53% at 1 to 4 years, respectively.

Conclusions:

Angioplasty/stenting of SMA and CT stenoses has a high initial technical success rate and acceptable early and late clinical outcomes; however, it is associated with a high incidence of late restenosis based on strict Doppler criteria.
Incidence of Renal Infarctions after Endovascular AAA Repair: Relationship to Infrarenal versus Suprarenal Fixation
Authors: Böckler Dittmar , Krauss Martin , Mannsmann Ulrich , Halawa Mustafa , Lange Ralph , Probst Thomas , Raithel Dieter
Published: March 2015

Purpose:

To analyze the incidence and etiology of renal infarctions following endovascular abdominal aortic aneurysm (AAA) repair detected on computed tomography (CT) and determine any association with infrarenal versus suprarenal fixation.

Methods:

Between August 1994 and October 2001, 663 patients (604 men; mean age 68.5 years, range 40–98) underwent endovascular AAA repair with predominately bifurcated (505, 77%) stent-grafts. About a third (202, 30%) of the devices were deployed in a suprarenal position. Contrast-enhanced CT scans were performed on days 10, 90, and 365 after operation and then annually. Two radiologists blinded to procedural details compared the preoperative and postoperative scans to identify renal infarctions from inadvertent renal artery occlusion by the endograft. Only patients with inadvertent infarctions were analyzed relative to endograft fixation position and stent-graft type.

Results:

Mean follow-up was 37 months (range 0.1–75). Overall renal infarction rate was 11.9% (n=79); 23 (3.4%) patients suffered from limited, segmental infarction due to intentional covering of preoperatively diagnosed accessory renal arteries. Unintentional renal ischemia was identified in 56 (8.5%) patients. In this subgroup, 39 (19%) were observed in the 202 patients with suprarenal fixation versus 17 (3.7%) in the 461 stent-grafts positioned infrarenally (RR 3.35, 95% CI 2.20 to 5.04, p < 0.00001). There was a significant correlation between the incidence of infarction and the device type (14.3% for modular grafts versus 5.6% for unibody designs, p = 0.0002). Seventeen (2.6%) patients suffered from unilateral kidney loss, with dialysis required in 2 cases. Creatinine and urea showed no significant postoperative elevation in the overall patient population, but both levels were significantly (p < 0.02) elevated in patients with complete unilateral renal infarcts.

Conclusions:

Transrenal fixation of aortic endografts had a 3-fold higher risk for renal infarction in this large patient population. There is no significant difference for specific endografts, but modular designs were associated with a higher rate of renal infarction. The need to occlude preoperatively diagnosed accessory renal arteries with an endograft should be considered a contraindication for current available devices.
Coil Embolization of Iliac Artery Aneurysms Developing after Abdominal Aortic Aneurysm Repair with a Conventional Bifurcated Graft
Authors: Sakamoto Ichiro , Mori Masakazu , Nishida Akifumi , Fukushima Aya , Sueyoshi Eijun , Hazama Shiro , Eishi Kiyoyuki , Hayashi Kuniaki
Published: March 2015

Purpose:

To evaluate the efficacy of embolizing iliac artery aneurysms (IAAs) developing after abdominal aortic aneurysm (AAA) repair.

Methods:

The records of 6 patients (5 men; mean age 79 years, range 61–87) with unilateral (n = 3) or bilateral (n = 3) IAAs that had developed after AAA repair were reviewed. In all patients, the limbs of the bifurcated graft were anastomosed end-to-end or end-to-side with the external iliac arteries during AAA repair. Before embolization, superior mesenteric artery (SMA) arteriography was done in all patients to evaluate collateral pathways to the inferior mesenteric artery (IMA).

Results:

The unilateral IAAs were treated by proximal and distal embolization. In 2 patients with bilateral IAAs, SMA angiography showed sufficient collateral flow to the IMA, so the aneurysms were treated by proximal embolization and packing. In the other bilateral IAA case, the left 6-cm IAA was treated by proximal and distal embolization, while the contralateral 3-cm IAA was not embolized because angiography demonstrated inadequate collateral flow to the IMA, indicating a possible risk of colon ischemia if both IAAs were embolized. Immediate postprocedural angiography in all patients showed complete exclusion of the IAAs. Mild buttock claudication occurred in 1 patient. There were no episodes of rupture over a mean 46-month follow-up.

Conclusions:

Embolization is a safe and effective alternative to open surgery for the treatment of IAAs that develop after AAA repair. However, before embolization, angiographic evaluation of collateral pathways to the IMA is essential to reduce the risk of colon ischemia.
Internal Iliac Artery Occlusion Using a Stent-Graft Tunnel during Endovascular Aneurysm Repair: A New Alternative to Coil Embolization
Authors: Rajasinghe Hiranya A. , Pigott John P. , Kritpracha Boonprasit , Corbey Mary Jo , Beebe Hugh G.
Published: March 2015

Purpose:

To report a new endovascular technique for internal iliac artery (IIA) occlusion during stent-graft treatment in patients with aortoiliac aneurysm.

Technique:

Stent-grafts measuring 20 to 28 mm in diameter and 37.5 mm long were deployed at the iliac bifurcation to occlude the IIA at its origin. Subsequent deployment of an aortic bifurcation endograft with ipsilateral extension into the external iliac artery was through this iliac stent-graft tunnel. This approach has been used in 5 patients with abdominal aortic aneurysm and common iliac artery aneurysm (n = 4) or isolated iliac artery aneurysm. Proximal IIA occlusion was achieved in all cases with no distal type I endoleak. IIA patency on the side opposite to the tunnel procedure was preserved in each case. No patient described new onset of pelvic ischemic symptoms. Over a mean 10-month follow-up (range 1–12), there was no secondary procedure required for type I endoleak. Three patients had a CIA aneurysm diameter change of −1, −4, and 0 mm at 1 year.

Conclusions:

This new method for IIA occlusion at its origin without coil embolization may prove to be a useful adjunct to endovascular aortoiliac aneurysm repair. The technique is simple, rapid, and may minimize the risk of pelvic ischemia.