Lower limb revascularization in patients with heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is a serious complication which occurs in patients treated with heparin. It is estimated that in clinical practice this syndrome can be encountered among 1-3% of patients who receive heparin treatment. This disease is often not diagnosed. The aim of this study was to evaluate the treatment of patients with diagnosed HIT syndrome who were qualified to revascularisation in the course of critical lower limb ischaemia. There were two cases of patients with diagnosed HIT syndrome who were treated in the Department of General and Vascular Surgery in Poznań. The results of revascular treatment of patients with diagnosed HIT syndrome were evaluated retrospectively. In all patients it was possible to perform revascular surgery of lower limbs after introducing an oral anticoagulant. In 2004 it was impossible to treat HIT syndrome with new generation anticoagulants. That is why oral anticoagulant (coumarin) treatment was introduced as a safe method and the only one available in our conditions. It enabled us to perform revascular surgery retaining INR indicator of 1.5-1.7.Małopłytkowość poheparynowa (HIT) jest poważnym powikłaniem występującym u chorych leczonych heparyną. Ocenia się, że w praktyce klinicznej zespół ten pojawia się u 1-3% osób poddanych terapii heparynowej i często jest to schorzenie nierozpoznane. Celem pracy była ocena leczenia chorych z rozpoznanym zespołem HIT, zakwalifikowanych do operacji rewaskularyzacyjnych w przebiegu krytycznego niedokrwienia kończyn dolnych. Przedstawiono przypadki dwóch chorych z rozpoznanym zespołem HIT, leczonych w Klinice Chirurgii Ogólnej i Naczyń w Poznaniu. Retrospektywnie oceniono wyniki leczenia rewaskularyzacyjnego chorych z rozpoznanym zespołem HIT. U wszystkich chorych włączenie doustnego antykoagulantu umożliwiło przeprowadzenie operacji rewaskularyzacyjnej kończyn dolnych. W 2004 roku z powodu braku możliwości leczenia zespołu HIT lekami przeciwkrzepliwymi nowej generacji, zastosowanie doustnych antykoagulantów (acenokumarolu) było metodą bezpieczną i w tym czasie jedynie dostępną w tych warunkach. Pozwoliła ona na przeprowadzenie operacji rewaskularyzacyjnej, przy zachowaniu wskaźnika INR na poziomie 1,5-1,7

Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy

Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86–1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91–1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable. Funding: UK Medical Research Council and Health Technology Assessment Programme

Session 17 Ecophysiology

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Research object as mechanism for ensuring research experiment reproducibility within virtual research environment

A Research Object (RO) is defined as a semantically rich aggregation of resources that bundles together essential information relating to experiments and investigations. This information is not limited merely to the data used and the methods employed to produce and analyze such data, but it may also include the people involved in the investigation as well as other important metadata that describe the characteristics, inter-dependencies, context and dynamics of the aggregated resources. As such, a research object can encapsulate scientific knowledge and provide a mechanism for sharing and discovering assets of reusable research and scientific knowledge within and across relevant communities, and in a way that supports reliability and reproducibility of investigation results. While there are no pre-defined constraints related to the type of resources a research object can contain, the following usually apply in the context of scientific research: data used and results produced; methods employed to produce and analyze data; scientific workflows implementing such methods; provenance and settings; people involved in the investigation; annotations about these resources, which are essential to the understanding and interpretation of the scientific outcomes captured by a research object. The example research object contains a workflow, input data and results, along with a paper that presents the results and links to the investigators responsible. Annotations on each of the resources (and on the research object itself) provide additional information and characterize, e.g. the provenance of the results. Therefore, exploitation of the RO model should be considered as a way to provide additional reliability and reproducibility of the research. The concept of the RO was introduced to the environment created in the EVER-EST project in the form of Virtual Research Environment (VRE). a group of Earth Scientists, who are observing, analyzing and modeling processes that take place on land and see, was examined against their needs and expectations about the possible improvements in their scientific work. The results show that scientist expectations are focused on knowledge sharing and reuse, and new forms of scholarly communications beyond pdf articles as supporting tools of knowledge cross-fertilization between their members. The Research Object concept seems a natural answer for these needs. However, the model, in order to be sufficient and usable, must become a part of the working environment and needs to be integrated with the actual tools. Therefore, great efforts have been undertaken to create a generic, technical solution – VRE , which implements the expected functionalities. In this article we present a concept of the VRE as a tool that takes advantage of the Research Object model in order to integrate and simplify the information exchange, as well as persist, share and discover assets of the reusable research. Moreover, we are presenting example scenarios of the VRE usage in the four different Earth Science domains

Validating the ACGT Oncosimulator with a Grid-Supported Visualisation Environment

The ACGT Oncosimulator is an integrated Grid-based system, under development within a 25-partner European-Japanese project, for patient-specific simulation of the response of a tumour and its surrounding tissue to various forms of therapy. The validation of the simulation code is an activity requiring extensive human-driven visual investigation of the influence of each of the dozens of parameters to the code, initially by comparing results from simulations carried out with different parameter values. This activity requires that users be supported in specifying simulation runs based on chosen parameter-value combinations, submitting the runs for execution on the Grid, then obtaining result visualisations that help in making the necessary comparisons. We report on our development and early use of the OncoRecipeSheet, an environment designed to meet these requirements

Restenosis after carotid endarterectomy: incidence and endovascular management.

Surgical procedures designed to restore vascular patency for a recurrent stenosis following carotid endarterectomy (CEA) are burdened with technical difficulties as well as with the possibility of serious neurological complications. An endovascular approach employing transluminal percutaneous angioplasty and stenting (PTAS) is a promising solution to these problems. We aimed to evaluate the incidence of carotid artery restenosis following CEA, and to evaluate the safety and efficacy of treating post-CEA restenosis with an endovascular technique (PTAS). One hundred and two patients who underwent CEA for symptomatic and asymptomatic stenosis were included in the analysis. Clinical and sonographic follow-up examinations identified carotid artery restenosis in 16 patients, who fulfilled our criteria for endovascular treatment. Carotid PTAS was performed on symptomatic patients with a stenosis over 60% of the artery lumen (n=7) and in asymptomatic patients with a stenosis over 80% (n=9). The post-PTAS patients were evaluated by duplex sonography every three months over a 24 month follow-up period for evidence of restenosis. The cumulative incidence of post-CEA carotid restenosis qualifying for PTAS was 9.3% during an average 12-month follow-up interval. The average time from CEA to carotid PTAS was 11 months. All 16 endovascular procedures were technically successful. All of the carotid arteries were widely patent following PTAS. There were no immediate perioperative complications. One patient died two days after carotid PTAS from a cerebral hemorrhage. Thirteen of the 16 patients remained asymptomatic and had no sonographic evidence of significant restenosis during the 24- month post-PTAS follow-up period. One patient developed a symptomatic 80% restenosis proximal to the stent six months after carotid PTAS. Another patient developed an asymptomatic 60% restenosis proximal to the stent at 24 months. One patient was lost to follow-up. Following CEA, there is a significant risk of developing a symptomatic or high-grade carotid artery restenosis requiring correction. Endovascular treatment (PTAS) of a recurrent stenosis after CEA is a safe and effective alternative to repeat carotid surgery