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| 14. |
- Govsyeyev, Nicholas, et al.
(författare)
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Rivaroxaban in Patients with Symptomatic Peripheral Artery Disease after Lower Extremity Bypass Surgery with Venous and Prosthetic Conduits
- 2023
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Ingår i: Journal of Vascular Surgery. - : Elsevier. - 0741-5214 .- 1097-6809. ; 77:4, s. 1107-1118.e2
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Patients with peripheral artery disease (PAD) requiring lower extremity revascularization (LER) are at high risk of adverse limb and cardiovascular events. VOYAGER PAD demonstrated that rivaroxaban significantly reduced this risk with an overall favorable net benefit in patients undergoing surgical revascularization; however, the efficacy and safety in those treated by surgical bypass including stratified by bypass conduit (venous or prosthetic) has not been described.METHODS: In the VOYAGER PAD trial, patients with PAD after surgical and endovascular infrainguinal LER were randomized to rivaroxaban 2.5 mg twice daily or placebo and followed for a median of 28 months. The primary endpoint was a composite of acute limb ischemia (ALI), major amputation of vascular etiology, myocardial infarction, ischemic stroke, or cardiovascular death. The principal safety outcome was Thrombolysis in Myocardial Infarction (TIMI) major bleeding. Index procedure details including conduit type (venous or prosthetic) were collected at baseline.RESULTS: Among 6564 randomized, 2185 (33%) underwent surgical LER. Of these, surgical bypass was performed in 1448 (66%), using prosthetic conduit in 773 (53%) and venous in 646 (45%). Adjusting for baseline differences and anatomic factors, the risk for unplanned limb revascularization in the placebo arm was 2.5-fold higher for those receiving prosthetic versus venous conduits (adjHR 2.53, 95% CI 1.65-3.90; p<0.001) while the risk for ALI was 3 times greater (adjHR 3.07, 95% CI 1.84-5.11; p<0.001). Rivaroxaban reduced the primary outcome in patients treated with bypass surgery (HR 0.78, 95% CI 0.62-0.98) with consistent benefits in those receiving venous (HR 0.66, 95% CI 0.49-0.96) and prosthetic (HR 0.87, 95% CI 0.66-1.15) conduits (pinteraction 0.254). In the overall trial, TIMI major bleeding was increased with rivaroxaban; however, numbers in those treated with bypass surgery were low (5 with rivaroxaban, 9 with placebo, HR 0.55, 95% CI 0.18-1.65) and not powered to show statistical significance.CONCLUSIONS: Surgical bypass with prosthetic conduit is associated with significantly higher rates of major adverse limb events relative to venous conduits even after adjusting for patient and anatomic characteristics. Adding rivaroxaban 2.5 mg twice daily to aspirin or dual antiplatelet therapy significantly reduces this risk, increases bleeding, but has a favorable benefit risk in patients treated with bypass surgery and regardless of conduit type. Rivaroxaban should be considered after lower extremity bypass for symptomatic PAD to reduce ischemic complications of the heart, limb, and brain.
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| 15. |
- Hess, C. N., et al.
(författare)
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A Structured Review of Antithrombotic Therapy in Peripheral Artery Disease With a Focus on Revascularization A TASC (InterSociety Consensus for the Management of Peripheral Artery Disease) Initiative
- 2017
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Ingår i: Circulation. - : Ovid Technologies (Wolters Kluwer Health). - 0009-7322 .- 1524-4539. ; 135:25, s. 2534-2555
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Tidskriftsartikel (refereegranskat)abstract
- Peripheral artery disease affects >200 million people worldwide and is associated with significant limb and cardiovascular morbidity and mortality. Limb revascularization is recommended to improve function and quality of life for symptomatic patients with peripheral artery disease with intermittent claudication who have not responded to medical treatment. For patients with critical limb ischemia, the goals of revascularization are to relieve pain, help wound healing, and prevent limb loss. The baseline risk of cardiovascular and limb-related events demonstrated among patients with stable peripheral artery disease is elevated after revascularization and related to atherothrombosis and restenosis. Both of these processes involve platelet activation and the coagulation cascade, forming the basis for the use of antiplatelet and anticoagulant therapies to optimize procedural success and reduce postprocedural cardiovascular risk. Unfortunately, few high-quality, randomized data to support use of these therapies after peripheral artery disease revascularization exist, and much of the rationale for the use of antiplatelet agents after endovascular peripheral revascularization is extrapolated from percutaneous coronary intervention literature. Consequently, guideline recommendations for antithrombotic therapy after lower limb revascularization are inconsistent and not always evidence-based. In this context, the purpose of this structured review is to assess the available randomized data for antithrombotic therapy after peripheral arterial revascularization, with a focus on clinical trial design issues that may affect interpretation of study results, and highlight areas that require further investigation.
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| 16. |
- Hess, Connie N., et al.
(författare)
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A Structured Review of Antithrombotic Therapy in Peripheral Artery Disease with a Focus on Revascularization : A TASC (InterSociety Consensus for the Management of Peripheral Artery Disease) Initiative
- 2017
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Ingår i: Circulation. - 0009-7322. ; 135:25, s. 2534-2555
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Forskningsöversikt (refereegranskat)abstract
- Peripheral artery disease affects >200 million people worldwide and is associated with significant limb and cardiovascular morbidity and mortality. Limb revascularization is recommended to improve function and quality of life for symptomatic patients with peripheral artery disease with intermittent claudication who have not responded to medical treatment. For patients with critical limb ischemia, the goals of revascularization are to relieve pain, help wound healing, and prevent limb loss. The baseline risk of cardiovascular and limb-related events demonstrated among patients with stable peripheral artery disease is elevated after revascularization and related to atherothrombosis and restenosis. Both of these processes involve platelet activation and the coagulation cascade, forming the basis for the use of antiplatelet and anticoagulant therapies to optimize procedural success and reduce postprocedural cardiovascular risk. Unfortunately, few high-quality, randomized data to support use of these therapies after peripheral artery disease revascularization exist, and much of the rationale for the use of antiplatelet agents after endovascular peripheral revascularization is extrapolated from percutaneous coronary intervention literature. Consequently, guideline recommendations for antithrombotic therapy after lower limb revascularization are inconsistent and not always evidence-based. In this context, the purpose of this structured review is to assess the available randomized data for antithrombotic therapy after peripheral arterial revascularization, with a focus on clinical trial design issues that may affect interpretation of study results, and highlight areas that require further investigation.
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| 17. |
- Hess, C. N., et al.
(författare)
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Acute Limb Ischemia in Peripheral Artery Disease Insights From EUCLID
- 2019
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Ingår i: Circulation. - : Ovid Technologies (Wolters Kluwer Health). - 0009-7322 .- 1524-4539. ; 140:7, s. 556-565
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Tidskriftsartikel (refereegranskat)abstract
- Background: Acute limb ischemia (ALI) is an important clinical event and an emerging cardiovascular clinical trial outcome. Risk factors for and outcomes after ALI have not been fully evaluated. Methods: EUCLID (Examining Use of Ticagrelor in Peripheral Artery Disease) randomized patients with peripheral artery disease to ticagrelor versus clopidogrel. Enrollment criteria included an ankle-brachial index <= 0.80 or previous lower extremity revascularization. Patients were grouped according to the primary outcome, postrandomization ALI hospitalization. Baseline factors associated with ALI were identified using Cox proportional hazards modeling. Models with ALI hospitalization as a time-dependent covariate were developed for secondary outcomes of major adverse cardiovascular events (myocardial infarction, cardiovascular death, ischemic stroke), all-cause mortality, and major amputation. Results: Among 13 885 patients, 1.7% (n=232) had 293 ALI hospitalizations (0.8 per 100 patient-years). Patients with versus without ALI were younger and more often had previous peripheral revascularization and lower baseline ankle-brachial index. Treatment during ALI hospitalization included endovascular revascularization (39.2%, n=115), surgical bypass (24.6%, n=72), and major amputation (13.0%, n=38). After multivariable adjustment, any previous peripheral revascularization (Hazard Ratio [HR] 4.7, 95% CI 3.3-6.8, P<0.01), baseline atrial fibrillation (HR 1.8, 95% CI 1.1-3.2, P=0.03), and baseline ankle-brachial index <= 0.60 (HR 1.3 per 0.10 decrease, 95% CI 1.1-1.5, P<0.01) were associated with higher ALI risk. Older age (HR 0.8 per 10-year increase, 95% CI 0.7-1.0, P=0.02) and baseline statin use (HR 0.7, 95% CI 0.5-0.9, P<0.01) were associated with lower risk for ALI. There was no relationship between randomized treatment to ticagrelor or clopidogrel and ALI. Among patients with previous revascularization, surgical versus endovascular procedures performed more than 6 months prior were associated with ALI (adjusted HR 2.63, 95% CI 1.75-3.96). In the overall population, ALI hospitalization was associated with subsequent MACE (adjusted HR 1.4, 95% CI 1.0-2.1, P=0.04), all-cause mortality (adjusted HR 3.3, 95% CI 2.4-4.6, P<0.01), and major amputation (adjusted HR 34.2, 95% CI 9.7-20.8, P<0.01). Conclusions: Previous peripheral revascularization, baseline atrial fibrillation, and lower ankle-brachial index identify peripheral artery disease patients at heightened risk for ALI, an event associated with subsequent cardiovascular and limb-related morbidity and mortality.
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| 18. |
- Khotyaintsev, Yu, V, et al.
(författare)
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Electron Heating by Debye-Scale Turbulence in Guide-Field Reconnection
- 2020
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Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 124:4
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Tidskriftsartikel (refereegranskat)abstract
- We report electrostatic Debye-scale turbulence developing within the diffusion region of asymmetric magnetopause reconnection with amoderate guide field using observations by the Magnetospheric Multiscale mission. We show that Buneman waves and beam modes cause efficient and fast thermalization of the reconnection electron jet by irreversible phase mixing, during which the jet kinetic energy is transferred into thermal energy. Our results show that the reconnection diffusion region in the presence of a moderate guide field is highly turbulent, and that electrostatic turbulence plays an important role in electron heating.
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| 19. |
- Le Contel, O., et al.
(författare)
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Lower Hybrid Drift Waves and Electromagnetic Electron Space-Phase Holes Associated With Dipolarization Fronts and Field-Aligned Currents Observed by the Magnetospheric Multiscale Mission During a Substorm
- 2017
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Ingår i: Journal of Geophysical Research - Space Physics. - : AMER GEOPHYSICAL UNION. - 2169-9380 .- 2169-9402. ; 122:12, s. 12236-12257
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Tidskriftsartikel (refereegranskat)abstract
- We analyze two ion scale dipolarization fronts associated with field-aligned currents detected by the Magnetospheric Multiscale mission during a large substorm on 10 August 2016. The first event corresponds to a fast dawnward flow with an antiparallel current and could be generated by the wake of a previous fast earthward flow. It is associated with intense lower hybrid drift waves detected at the front and propagating dawnward with a perpendicular phase speed close to the electric drift and the ion thermal velocity. The second event corresponds to a flow reversal: from southwward/dawnward to northward/duskward associated with a parallel current consistent with a brief expansion of the plasma sheet before the front crossing and with a smaller lower hybrid drift wave activity. Electromagnetic electron phase-space holes are detected near these low-frequency drift waves during both events. The drift waves could accelerate electrons parallel to the magnetic field and produce the parallel electron drift needed to generate the electron holes. Yet we cannot rule out the possibility that the drift waves are produced by the antiparallel current associated with the fast flows, leaving the source for the electron holes unexplained.
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| 20. |
- Masia, NDE, et al.
(författare)
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Corrosion performance of Ti-Cu alloys targeted for biomedical applications
- 2022
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Ingår i: Suid-Afrikaanse tydskrif vir natuurwetenskap en tegnologie. - : Medpharm Publications. - 0254-3486 .- 2222-4173. ; 40:1, s. 244-250
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Tidskriftsartikel (refereegranskat)abstract
- The Thermo-Calc™ program and TTTI3 database were used to predict the phases in Ti-Cu with 5, 25, and 40 wt% Cu. Based on the predicted results, experimental work was conducted and the Ti-Cu alloys were produced in a button arc furnace, and characterised in the as-cast and the annealed condition (900°C) followed by water quenching. Microstructures and compositions were determined using an electron probe micro-analyser, and the phases were identified by X-ray diffraction. The corrosion performance was measured by potentiodynamic polarisation in a phosphate buffered saline solution at 37 °C at 7.4 pH while purging with nitrogen gas. The Ti-5Cu and Ti-25Cu alloys comprised (αTi) and Ti2Cu phases, the Ti-40Cu alloy comprised Ti2Cu and TiCu. Although the addition of copper decreased the corrosion performance by down to 75%, the corrosion rates were still within the acceptable range (0.02-0.13 mm/y) for biocompatibility of metallic implants. Annealing at 900 °C did not improve the corrosion performance.
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