Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The vast majority of acute coronary syndrome (ACS) trials conducted over the past two decades support the view that women have persistently higher mortality and morbidity despite the introduction of new medical therapies and devices. Even after adjustment for older age, higher prevalence of diabetes, hypertension, heart failure, smaller vessel size, and late presentation, some studies still point to a persistent sex disadvantage. Even in contemporary practice, women continue to have longer delays in presentation and treatment. Selection bias in unstable angina/non-ST-elevation myocardial infarction (UA/NSTEMI) trials allows inclusion of large numbers of women with clinically insignificant coronary disease and may mistakenly shift results toward apparent benefit of a less aggressive approach. This bias causes further difficulty in determining efficacy and safety of new antithrombotic agents such as direct thrombin inhibitors and glycoprotein IIb/IIa inhibitors across the spectrum of ACS. In trials of UA/NSTEMI, use of objective evidence of ischemia such as elevated troponin levels, would greatly assist the determination of efficacy and benefit in women. Enrollment of more women in clinical trials and timely sex-specific analysis would promote a better understanding of the role of female gender in ACS and would facilitate better care of all patients.
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PMID:Acute coronary syndromes in women: is treatment different? Should it be? 1518 98

Platelet activation and aggregation have become increasingly recognized as the primary processes involved in the cascade that leads to thrombus formation in atherosclerotic vascular disease. Glycoprotein IIb/IIIa receptor inhibitors (GPI) favorably impact thrombus formation and distal embolization by inhibiting the final common pathway of platelet aggregation. Glycoprotein IIb/IIIa inhibitors have been used effectively in a wide variety of clinical scenarios including unstable angina, non-ST segment elevation myocardial infarction, ST segment elevation myocardial infarction, and low and high risk percutaneous coronary interventions with and without intracoronary stenting, however there is limited data regarding the use of these potent antiplatelet agents in the setting of extracardiac vascular disease. This article will review the non-cardiac applications of glycoprotein IIb/IIIa inhibitors in the setting of acute ischemic stroke, carotid and vertebral angioplasty and stenting, acute critical limb ischemia, and percutaneous interventions in peripheral arterial occlusive disease.
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PMID:Noncardiac applications of glycoprotein IIb/IIIa inhibitors. 1527 67

Although the efficacy of glycoprotein IIb/IIIa inhibition in non-ST-elevation acute coronary syndromes is greatest in patients who undergo percutaneous coronary intervention (PCI), it was hypothesized that high-risk patients managed without PCI also benefit. The TIMI risk score was calculated for 1,570 patients randomized to tirofiban plus heparin versus heparin in the Platelet Receptor Inhibition in Ischemic Syndrome Management in Patients Limited by Unstable Signs and Symptoms trial. In high-risk patients (score > or =4) treated without PCI, tirofiban reduced the risk for death, myocardial infarction, and refractory ischemia at 30 days (28.8% vs 21.9%; odds ratio [OR] 0.69, p = 0.04). This benefit was similar in magnitude as that for patients who underwent PCI (32.4% vs 22.2%; OR 0.60, p = 0.06). No benefit was evident in low-risk patients.
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PMID:Usefulness of tirofiban among patients treated without percutaneous coronary intervention (TIMI high risk patients in PRISM-PLUS). 1537 86

Acute ischemic chest pain at rest consistent with unstable angina or non-ST-elevation myocardial infarction is a common problem that may cause death or recurrent myocardial infarction within 30 days unless identified and risk stratified acutely. The latter may be done within 15 minutes by the history, physical exam, and electrocardiogram, and is aided by the measurement of troponin T/I. According to the Agency for Health Care Policy and Research guidelines, low-risk patients can be discharged home and rechecked within 72 hours. Intermediate-risk patients with no ST-segment changes with continuous monitoring and no elevation of troponin should undergo exercise stress testing by electrocardiogram (or nuclear or echocardiographic evaluation if electrocardiogram is non-analyzable). Patients with a negative stress test are low risk (no death or myocardial infarction at 30 days or 6 months) and can be discharged home. Patients with a positive test or who are at high risk according to the Agency for Health Care Policy and Research guidelines should undergo acute invasive testing for possible revascularization. Aspirin and low molecular weight heparin or unfractionated heparin, along with anti-ischemia therapy, is indicated in intermediate- or high-risk patients. The addition of clopidogrel is indicated in these patients, except in those who are potential candidates for coronary artery bypass graft. Platelet glycoprotein IIb/IIIa inhibitors are indicated in high-risk patients likely to undergo percutaneous coronary intervention, should be started early if recurrent ischemia occurs, but are not indicated in lower-risk patients who do not require percutaneous coronary intervention. Intensive secondary prevention should be started before dismissal.
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PMID:Acute coronary syndromes: pathogenesis, acute diagnosis with risk stratification, and treatment. 1553 72

Pharmacologic reperfusion of patients with acute ST segment elevation myocardial infarction is designed to achieve prompt high-quality reperfusion, prevent recurrent ischemia and reinfarction, maintain long-term patency, and to enhance patient survival and quality of life. Because monotherapy with fibrinolytics is by itself unable to achieve all of these objectives, antithrombotic, anti-platelet, and other novel agents are required. We discuss herein the role of unfractionated and enoxaparin, the potential added value of direct thrombin inhibitors, and the importance of aspirin. Despite the promise of glycoprotein IIb/IIIa inhibitors, risks associated with intracranial hemorrhage in the elderly have led to restraint in their application to broad populations. Facilitation of urgent percutaneous coronary intervention with combination reduced-dose fibrinolytic and glycoprotein IIb/IIIa inhibitors remains a promising potential future path. The future is likely to emphasize greater application of the already effective therapies at our disposal and the development of novel anti-platelet and anti-thrombin agents as well as those directed toward inflammation.
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PMID:A marriage of enhancement: fibrinolysis and conjunctive therapy. 1558 23

Acute coronary syndromes (ACS) represent a continuum from unstable angina to non-ST-elevation myocardial infarction. ACS is the preferred diagnostic term for non transmural myocardial infarction. The different forms of ACS share a common anatomic substrate consisting of atherosclerotic plaque rupture or erosion, with variable degrees of thrombus formation and compromised blood flow to viable myocardium. Patients with ACS have a heterogeneous profile of short- and mid-term adverse outcomes and require a tailored approach. Recent major advances in the management of ACS have emphasized the importance of earlier identification of higher-risk patients, whose outcome might be improved by aggressive revascularization. However, during the past several years, numerous studies have shown a significant difference in the prognosis of women and men with ACS. Some reports have concluded that women have a worse prognosis than men after thrombolytic therapy and/or coronary angioplasty with stenting for myocardial reperfusion. The aim of our retrospective study was to determine sex differences in outcomes after early percutaneous intervention (PCI) in high-risk patients with acute coronary syndromes (ACS). A total of 694 consecutive patients (151 women with 233 treated lesions and 543 men with 850 treated lesions) were included. Enrollments were limited to ACS patients judged to be at high risk [unstable angina/non ST-elevation myocardial infarction with recurrent ischemia/dynamic ST segment changes (53.6% vs 52.4%) or post-infarction unstable angina (46.4% vs 47.6%)] who underwent PCI within 24 hours of admission if the coronary anatomy was deemed suitable. The two groups were well matched for clinical and lesion characteristics, except that the women, as in other studies, were older (67.9 +/- 11.3 vs 62.3 +/- 12.3 years) and had a higher prevalence of hypertension. All the lesions were treated by stent implantation, and glycoprotein IIb/IIIa inhibitors were used similarly in the two sexes (27.1% of women, 30.5% of men). The success rates were similar (94% and 93.7%), with a similar incidence of in-hospital MACE (4% vs 3.8%, p = 0.56). After a mean follow-up of 564 +/- 294 days, the two groups had similar rates of mortality (2% vs 3.2%), myocardial infarction (6.7% vs 7.1%) and repeated revascularization (7.2% vs 8.3%). The respective event-free survival rates were 88 +/- 60.3% and 83 +/- 0.3% at 1 year and 87% vs 78 +/- 0.2% at 2 years (p = 0.58). Previous studies have shown increased morbidity and mortality associated with recurrent ischemia and myocardial infarction in women after acute revascularization for ACS. Our study confirms that aggressive revascularization offers a comparable survival benefit in the two sexes. Women with ACS who are at high risk derive the same benefit as men from early angioplasty and coronary stenting of the culprit lesion, with satisfactory in-hospital and mid-term outcomes.
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PMID:[Prognosis after acute coronary syndrome. Lack of difference according to the sex]. 1558 51

1. Ischaemia-reperfusion (IR) injury is an important contributor to tissue damage and has been shown to be attenuated by preconditioning (PC) in some animal models. A recent report has suggested that the forearm can be used for the study of this phenomenon in humans. We aimed to reproduce and further characterize this model. 2. Healthy young adult volunteers (mean (+/-SEM) age 32+/-6 years) were studied on two occasions. During one visit, IR alone was induced by 10 min of upper arm cuff occlusion, whereas on another occasion a PC stimulus (three 3 min cuff inflations) preceded IR. Endothelial function in the ischaemic arm was assessed by measuring arterial flow-mediated dilatation (FMD) and by calculation of forearm blood flow at baseline and 15 and 60 min after IR. Systemic venous blood was sampled from the non-ischaemic arm at baseline, after PC and at 2, 15 and 30 min after IR to assess neutrophil/leucocyte (CD11b) and platelet (bound glycoprotein IIb/IIIa and fibrinogen) activation, as well as numbers of platelet-leucocyte complexes, which were determined by flow cytometry. Because of a lack of measurable effects, the IR experiment was repeated with 20 min ischaemia in six subjects. 3. Five females and eight males completed the study. Flow-mediated dilatation was significantly impaired 30 min after IR (4.1 vs 6.2% at baseline; P<0.05);however, this was not significantly attenuated by ischaemic PC (FMD reduction at 30 min compared with baseline was 2.1+/-0.5% with IR alone and 2.6+/-1.4% with IR after PC; NS). No significant effect was seen on the number of platelet-leucocyte aggregates or on white cell or platelet activation after IR alone or after IR with PC (P>0.6 for all comparisons). Similar results were obtained in six subjects studied subjected to 20 min ischaemia. 4. In conclusion, in healthy young adults, brief periods of skeletal muscle ischaemia lead to arterial endothelial dysfunction, but no significant platelet or white cell activation. Preconditioning does not attenuate this effect on the endothelium. Further experiments with longer ischaemia times and varying PC stimuli may be necessary to produce measurable effects; however, this may prove difficult in conscious human subjects.
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PMID:Reperfusion injury in the human forearm is mild and not attenuated by short-term ischaemic preconditioning. 1573 Apr 40

Inflammation and platelet activation are critical phenomena in the setting of acute coronary syndromes. Platelets may contribute to increase ischemic injury by enhancing the inflammatory response of leukocytes and endothelial myocardial cells. Pharmacological inhibition of platelet activation prevents ischemic complications in patients with coronary diseases. Agents directed against the integrin glycoprotein IIb/IIIa (GP IIb/IIIa) receptor not only inhibit platelet aggregation but also have been demonstrated to limit the inflammatory response in acute coronary syndromes. The question then raised is if the inhibition of platelet activation by other mechanisms than the blockade of GP IIb/IIIa may also exert anti-inflammatory effects. The aim of the present study was to analyze if clopidogrel may exert anti-inflammatory effects during the acute phase of myocardial infarction. A ligature was placed around the left anterior descending coronary artery of New Zealand White rabbits. After 15 min of ischemia, the myocardium was reperfused and the ischemic coronary artery was isolated 24 h after the ischemia. A group of ischemic rabbits was given a single oral dose of clopidogrel (20 mg kg(-1)) just after the arterial occlusion and the animal was recovered. Sham-operated animals served as control. P-selectin expression was significantly increased in infarcted rabbits with respect to control rabbits. Clopidogrel administration reduced P-selectin expression with respect to untreated infarcted rabbits. CD40 ligand and tissue factor expression was increased in the ischemic coronary artery and reduced after clopidogrel administration. Clopidogrel also protected endothelial nitric oxide synthase protein expression in the ischemic coronary artery, a protein that has been found downregulated under inflammatory conditions. In conclusion, inhibition of platelet activation by clopidogrel exerted anti-inflammatory effects on the ischemic coronary artery.
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PMID:Effect of clopidogrel on the expression of inflammatory markers in rabbit ischemic coronary artery. 1604 1

The mechanisms by which T cells contribute to the hepatic inflammation during antigen-independent ischemia/reperfusion (I/R) are not fully understood. We analyzed the recruitment of T cells in the postischemic hepatic microcirculation in vivo and tested the hypothesis that T cells interact with platelets and activate sinusoidal endothelial cells, resulting in microvascular dysfunction followed by tissue injury. Using intravital videofluorescence microscopy, we show in mice that warm hepatic I/R (90/30-140 min) induces accumulation and transendothelial migration of CD4+, but not CD8+ T cells in sinusoids during early reperfusion. Simultaneous visualization of fluorescence-labeled CD4+ T cells and platelets showed that approximately 30% of all accumulated CD4+ T cells were colocalized with platelets, suggesting an interaction between both cell types. Although interactions of CD4+/CD40L-/- T cells with CD40L-/- platelets in wild-type mice were slightly reduced, they were almost absent if CD4+ T cells and platelets were from CD62P-/- mice. CD4 deficiency as well as CD40-CD40L and CD28-B7 disruption attenuated postischemic platelet adherence in the same manner as platelet inactivation with a glycoprotein IIb/IIIa antagonist and reduced neutrophil transmigration, sinusoidal perfusion failure, and transaminase activities. Treatment with an MHC class II antibody, however, did not affect I/R injury. In conclusion, we describe the type, kinetic, and microvascular localization of T cell recruitment in the postischemic liver. CD4+ T cells interact with platelets in postischemic sinusoids, and this interaction is mediated by platelet CD62P. CD4+ T cells activate endothelium, increase I/R-induced platelet adherence and neutrophil migration via CD40-CD40L and CD28-B7-dependent pathways, and aggravate microvascular/hepatocellular injury.
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PMID:CD4+ T cells contribute to postischemic liver injury in mice by interacting with sinusoidal endothelium and platelets. 1644 Mar 42

Coronary ischemia augments inhomogeneity in ventricular repolarization. Decrease in the QT dispersion (QTd) following restoration of coronary blood flow to the ischemic myocardium by successful percutaneous coronary intervention (PCI) is an expected outcome. The purpose of the study was to seek whether glycoprotein IIb/IIIa (GP IIb/IIIa) inhibition has additional beneficial effects on QT dispersion after angiographically successful PCI. The study involved 111 consecutive patients scheduled for elective coronary balloon angioplasty with or without stent implantation. Sixty patients (mean age 58 +/-9) were randomized to receive standard therapy including preprocedural aspirin, ticlopidine, and IV heparin, and 51 patients (mean age 54 +/-10) were randomized to receive additional IV tirofiban infusion before the lesion was crossed with the guidewire. Standard 12-lead simultaneous ECG recordings for the measurement of QTd and corrected QTd (QTcd) (calculated by using Bazett's formula) were obtained before and immediately after the procedure, and at the 6th, and 24th hours. Blood samples for detection of postprocedural myocardial damage (CK-MB and cTn-I) were taken before and immediately after the procedure, at the 6th, 12th, and 24th hours. In total, 128 stenoses were treated with PCI. Seventy of these lesions were in the standard therapy group and 58 in the tirofiban group. QTd and QTcd were not statistically different between the 2 groups before and immediately after the procedure and at the 6th hours, but at the 24th hour QTd and QTcd were significantly longer in the standard therapy group (p=0.047 and p=0.001, respectively). Postprocedural troponin-I elevation (B=0.692, p=0.037), maximum inflation pressure (B=0.182, p=0.001), and previous myocardial infarction (MI) (B=0.885, p=0.004) were defined as the predictors of the final QT dispersion at the 24th hour. QT dispersion significantly decreased after successful percutaneous coronary intervention. GP IIb/IIIa inhibition therapy was not superior by means of recovery of increased QT dispersion during the early hours of the intervention, but it prevented minor myocardial necrosis and provided more long-lasting recovery in QT dispersion as compared with heparin therapy. This impact of GP IIb/IIIa receptor inhibition on QTd may be a possible mechanism by which these drugs reduce cardiovascular events after PCI.
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PMID:Impacts of glycoprotein IIb/IIIa inhibition on QT dispersion after successful percutaneous coronary intervention. 1670 87


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