198 resultados para Ischaemia
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Treatment of dialysis access-related hand ischaemia with preservation of the access remains an issue. We report the case of a patient presenting critical hand ischaemia 2 years after proximalisation of a distal radio-cephalic fistula with preservation of the original access. After valvulotomy, the distal cephalic vein was used as in situ bypass and directly anastomosed to the distal brachial artery, providing a direct flow to the hand. This procedure relieved the hand ischaemia without sacrificing the functioning fistula. Six months later, the fistula and bypass were still patent, showing that flow reversal of a previous fistula can be an efficient strategy to correct dialysis access-related hand ischaemia in selected cases.
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Spinal cord ischaemia is rare in childhood and information on clinical presentation and outcome is scarce.
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Toll-like receptors (TLRs) are key receptors of the innate immune system which are expressed on immune and nonimmune cells. They are activated by both pathogen-associated molecular patterns and endogenous ligands. Activation of TLRs culminates in the release of proinflammatory cytokines, chemokines, and apoptosis. Ischaemia and ischaemia/reperfusion (I/R) injury are associated with significant inflammation and tissue damage. There is emerging evidence to suggest that TLRs are involved in mediating ischaemia-induced damage in several organs. Critical limb ischaemia (CLI) is the most severe form of peripheral arterial disease (PAD) and is associated with skeletal muscle damage and tissue loss; however its pathophysiology is poorly understood. This paper will underline the evidence implicating TLRs in the pathophysiology of cerebral, renal, hepatic, myocardial, and skeletal muscle ischaemia and I/R injury and discuss preliminary data that alludes to the potential role of TLRs in the pathophysiology of skeletal muscle damage in CLI.
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Patients with critical limb ischaemia (CLI) are usually elderly and suffer from several co-morbidities. The goal of surveillance after both endovascular and surgical revascularization for CLI is not only the protection of re-established distal perfusion and sustained ambulation but also the reduction of systemic atherothrombotic risk and mortality by ensuring continued best medical care. However, preferred format and rhythm of structured follow-up programs have remained controversial, mainly because of lack of compelling evidence. This review aims to summarize and to appraise available information critically. Thereby, it underlines the importance of systematic surveillance after both surgical and endovascular revascularization for CLI. Recent European guidelines are considered and areas of uncertainty are highlighted and discussed. According to currently available literature and recent guidelines, the early duplex scan is justified in all patients undergoing endovascular or surgical distal revascularization for CLI. There is no best level evidence supporting continued long term duplex surveillance of revascularizations with normal findings at early duplex scan, whereas those patients with abnormal early duplex scan or high risk revacularization are likely to benefit from continued duplex surveillance. Regular clinical follow-up is suggested and clinical deterioration should trigger duplex scanning to ensure revascularization patency.
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Endovascular therapy is a rapidly evolving field for the treatment of patients with peripheral arterial disease, and a magnitude of studies reporting on various modern revascularization concepts have been recently published. Thus, studies assessing the efficacy of endovascular therapy of peripheral arteries do not operate with uniformly defined endpoints, rendering a direct comparison of studies difficult. The purpose of this consensus statement is to highlight differences in the terminology used in the current literature and to propose some standardized criteria that must be considered when reporting results of endovascular revascularization for chronic ischaemia of lower limb arteries.
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AIMS: To determine the effect of anti-ischaemic drug therapy on long-term outcomes of asymptomatic patients without coronary artery disease (CAD) history but silent exercise ST-depression. METHODS AND RESULTS: In a randomized multicentre trial, 263 of 522 asymptomatic subjects without CAD but at least one CAD risk factor in whom silent ischaemia by exercise ECG was confirmed by stress imaging were asked to participate. The 54 (21%) consenting patients were randomized to anti-anginal drug therapy in addition to risk factor control (MED, n = 26) or risk factor control-only (RFC, n = 28). They were followed yearly for 11.2 +/- 2.2 years. During 483 patient-years, cardiac death, non-fatal myocardial infarction, or acute coronary syndrome requiring hospitalization or revascularization occurred in 3 (12%) of MED vs. 17 (61%) of RFC patients (P < 0.001). In addition, MED patients had consistently lower rates of exercise-induced ischaemia during follow-up, and left ventricular ejection fraction remained unchanged (-0.7%, P = 0.597) in contrast to RFC patients in whom it decreased over time (-6.0%, P = 0.006). CONCLUSION: Anti-ischaemic drug therapy and aspirin seem to reduce cardiac events in subjects with asymptomatic ischaemia type I. In such patients, exercise-induced ST-segment depression should be verified by stress imaging; if silent ischaemia is documented, anti-ischaemic drug therapy and aspirin should be considered.
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The prevention of ischaemia and the adequate restitution of blood flow to ischaemic tissue are pivotal to halt the progression of cellular injury associated with decreased oxygen and nutrient supply. Accordingly, the search for novel strategies which aim at preventing ischaemia-reperfusion-induced tissue damage is still of major interest in flap surgery. Preconditioning represents an elegant approach to render the tissue more resistant against deleterious ischaemic insults. For many decades, 'surgical delay' has been the standard method of tissue preconditioning. During the last 10 years, ischaemic preconditioning was added to the repertoire of plastic surgeons to protect flaps from ischaemic necrosis. The invasiveness and expenditure of time of these procedures, however, have always been major drawbacks, hindering a wide distribution in clinical practice. Consequently, the motivation has all along been to further refine and simplify protective strategies. Recent experimental studies have now shown that efficient protection from ischaemic necrosis can also be achieved by remote preconditioning or pretreatment with chemical agents and growth factors, which mimic the action of surgical delay and ischaemic preconditioning. In addition, the local application of unspecific stressors, including both heating and cooling, have been shown to effectively improve flap microcirculation and, thus, tissue survival. In view of successful translational research, it is now time that the efficacy of these novel preconditioning procedures is proven in prospective randomised clinical trials.
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AIMS: Intravascular inflammatory events during ischaemia/reperfusion injury following coronary angioplasty alter and denudate the endothelium of its natural anticoagulant heparan sulfate proteoglycan (HSPG) layer, contributing to myocardial tissue damage. We propose that locally targeted cytoprotection of ischaemic myocardium with the glycosaminoglycan analogue dextran sulfate (DXS, MW 5000) may protect damaged tissue from reperfusion injury by functional restoration of HSPG. METHODS AND RESULTS: In a closed chest porcine model of acute myocardial ischaemia/reperfusion injury (60 min ischaemia, 120 min reperfusion), DXS was administered intracoronarily into the area at risk 5 min prior to reperfusion. Despite similar areas at risk in both groups (39+/-8% and 42+/-9% of left ventricular mass), DXS significantly decreased myocardial infarct size from 61+/-12% of the area at risk for vehicle controls to 39+/-14%. Cardioprotection correlated with reduced cardiac enzyme release creatine kinase (CK-MB, troponin-I). DXS abrogated myocardial complement deposition and substantially decreased vascular expression of pro-coagulant tissue factor in ischaemic myocardium. DXS binding, detected using fluorescein-labelled agent, localized to ischaemically damaged blood vessels/myocardium and correlated with reduced vascular staining of HSPG. CONCLUSION: The significant cardioprotection obtained through targeted cytoprotection of ischaemic tissue prior to reperfusion in this model of acute myocardial infarction suggests a possible role for the local modulation of vascular inflammation by glycosaminoglycan analogues as a novel therapy to reduce reperfusion injury.
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OBJECTIVE This study tested the hypotheses that intermittent coronary sinus occlusion (iCSO) reduces myocardial ischaemia, and that the amount of ischaemia reduction is related to coronary collateral function. DESIGN Prospective case-control study with intraindividual comparison of myocardial ischaemia during two 2-min coronary artery balloon occlusions with and without simultaneous iCSO by a balloon-tipped catheter. SETTING University Hospital. PATIENTS 35 patients with chronic stable coronary artery disease. INTERVENTION 2-min iCSO. MAIN OUTCOME MEASURES Myocardial ischaemia as assessed by intracoronary (i.c.) ECG ST shift at 2 min of coronary artery balloon occlusion. Collateral flow index (CFI) without iCSO, that is, the ratio between mean distal coronary occlusive (Poccl) and mean aortic pressure (Pao) both minus central venous pressure. RESULTS I.c. ECG ST segment shift (elevation in all) at the end of the procedure with iCSO versus without iCSO was 1.33±1.25 mV versus 1.85±1.45 mV, p<0.0001. Regression analysis showed that the degree of i.c. ECG ST shift reduction during iCSO was related to CFI, best fitting a Lorentzian function (r(2)=0.61). Ischaemia reduction with iCSO was greatest at a CFI of 0.05-0.20, whereas in the low and high CFI range the effect of iCSO was absent. CONCLUSIONS ICSO reduces myocardial ischaemia in patients with chronic coronary artery disease. Ischaemia reduction by iCSO depends on coronary collateral function. A minimal degree of collateral function is necessary to render iCSO effective. ICSO cannot manifest an effect when collateral function prevents ischaemia in the first place.
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AIMS To investigate a pressure-controlled intermittent coronary sinus occlusion (PICSO) system in an ischaemia/reperfusion model. METHODS AND RESULTS We randomly assigned 18 pigs subjected to 60 minutes ischaemia by left anterior descending (LAD) coronary artery balloon occlusion to PICSO (n=12, groups A and B) or to controls (n=6, group C). PICSO started 10 minutes before (group A), or 10 minutes after (group B) reperfusion and was maintained for 180 minutes. A continuous drop of distal LAD pressure was observed in group C. At 180 minutes of reperfusion, LAD diastolic pressure was significantly lower in group C compared to groups A and B (p=0.02). LAD mean pressure was significantly less than the systemic arterial mean pressure in group C (p=0.02), and the diastolic flow slope was flat, compared to groups A and B (p=0.03). IgG and IgM antibody deposition was significantly higher in ischaemic compared to non-ischaemic tissue in group C (p<0.05). Significantly more haemorrhagic lesions were seen in the ischaemic myocardium of group C, compared to groups A and B (p=0.002). The necrotic area differed non-significantly among groups. CONCLUSIONS PICSO was safe and effective in improving coronary perfusion pressure and reducing antibody deposition consistent with reduced microvascular obstruction and ischaemia/reperfusion injury.
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INTRODUCTION Acute leg ischaemia (ALI) is a common vascular emergency for which new minimally invasive treatment options were introduced in the 1990s. The aim of this study was to determine recent hospital trends for ALI in England and to assess whether the introduction of the new treatment modalities had affected management. METHODS Routine hospital data covering ALI were provided by Hospital Episode Statistics for the years 2000 to 2011 and mortality data were obtained from the Office for National Statistics. All data were age standardised, reported per 100,000 of the population, and stratified by age band (60-74 years and ≥75 years) and sex. RESULTS Hospital admissions have risen significantly from 60.3 to 94.3 per 100,000 of the population, with an average annual increase of 6.2% since 2003 (p<0.001). The rise was greater in the older age group (from 79.9 to 134.4 vs 49.3 to 73.0) and yet procedures for ALI have shown a significant decrease since 2000 from 14.3 to 12.4 per 100,000 (p=0.013), independent of age and sex. Open embolectomy of the femoral artery remains the most common procedure and the proportion of endovascular interventions showed only a small increase. Only a few deaths were attributed to ALI (range: 95-150 deaths per year). CONCLUSIONS Hospital workload for ALI has increased, particularly since 2003, but this trend does not appear to have translated into increased endovascular or surgical activity.