Unstable angina syndromes

GPIIb/IIIa antagonists have to be administered parenterally. They are currently used prophylactically during intracoronary interventions such as percutaneous transluminal revascularization with balloon angioplasty or intracoronary stenting, as well as to treat acute coronary syndromes like unstable angina and acute myocardial infarction. The main complications... 

Acute coronary syndromes most often result from a physical disruption of the fibrous cap, either frank cap fracture or superficial endothelial erosion, allowing the blood to make contact with the thrombogenic material in the lipid core or the subendothelial region of the intima. This contact initiates the formation of a thrombus, which can lead to a sudden and dramatic blockade of blood flow through the affected artery. If the thrombus is nonocclusive or transient, it may either be clinically silent or manifest as symptoms characteristic of unstable angina. Importantly, if collateral vessels have previously formed, for example, due to chronic ischemia produced by multi vessel disease, even total occlusion of one coronary artery may not lead to an acute myocardial infarction. 

O Ischemic heart disease results from an imbalance between myocardial oxygen demand and oxygen supply that is most often due to coronary atherosclerosis. Common clinical manifestations of ischemic heart disease include chronic stable angina and the acute coronary syndromes of unstable angina, non-ST-segment elevation myocardial infarction, and ST-segment elevation myocardial infarction. 

Acute coronary syndromes is a term that includes all clinical syndromes compatible with acute myocardial ischemia resulting from an imbalance between myocardial oxygen demand and supply.3 In contrast to stable angina, an ACS results primarily from diminished myocardial blood flow secondary to an occlusive or partially occlusive coronary artery thrombus. Acute coronary syndromes are classified according to electrocardiogram (ECG) changes into STE ACS (STE MI) or NSTE ACS (NSTE MI and unstable angina) (Fig. 5-1). An STE MI, formerly... 

Acute coronary syndromes Ischemic chest discomfort at rest, most often accompanied by ST-segment elevation, ST-segment depression, or T-wave inversion on the 12-lead electrocardiogram. Furthermore, it is caused by plaque rupture and partial or complete occlusion of the coronary artery by thrombus. Acute coronary syndromes include myocardial infarction and unstable angina. Former terms used to describe types of acute coronary syndromes include Q-wave myocardial infarction, non-Q-wave myocardial infarction, and unstable angina. 

A specific immunoassay for measuring two-chain factor VIIa levels in plasma has been developed to identify activation of factor VII in patients with acute coronary syndromes suchs as myocardial infarction and unstable angina (12). Because regulation of factor VIIa is believed to be mediated by tissue factor pathway inhibitor (TFPI), its measurement is also useful in assessing thombotic and cardio-vasular disorders. Because TFPI is released by heparin, its measurement is also useful in assessing the efficacy of heparin and endothelial cell function (93). 

Acute coronary syndrome For patients with acute coronary syndrome (unstable angina/non-Q-wave Ml) including patients who are to be managed medically and those who are to be managed with percutaneous coronary intervention (with or without stent) or coronary artery bypass graft (CABG), clopidogrel has been shown to decrease the rate of a combined endpoint of cardiovascular death. Ml, or stroke, as well as the rate of a combined endpoint of cardiovascular death. Ml, stroke, or refractory ischemia. 

Drug therapy of acute coronary syndromes including unstable angina and non-Q-wave myocardial infarction includes use of aspirin, heparin and anti-ischaemic drugs and is similar in older patients to other age groups. Activation of platelet thromboxane production in the coronary circulation has been demonstrated in unstable angina. The risk of myocardial infarction or death is reduced by approximately 50% by early aspirin therapy in recommended doses of 160-325 mg per day and continued... 

Safefy and effectiveness have not been established in patients with unstable angina who are not undergoing PTCA or in patients with other acute coronary syndromes... 

Angina pectoris, hypertension, congestive heart failure, acute myocardial ischaemia, acute pulmonary oedema, unstable coronary syndromes especially when associated with elevated filling pressures. Nitrate therapy may exaggerate outflow obstruction in hypertrophic obstructive cardiomyopathy. 

Altman R, Luciardi HL, Muntaner J, etal, Efficacy assessment of meloxicam, a preferential cyclooxygenase-2 inhibitor, in acute coronary syndromes without ST-segment elevation the Nonsteroidal Anti-Inflammatory Drugs in Unstable Angina Treatment-2 (NUT-2) pilot study, Circulation 2002 106 191-195. 

Patients with acute coronary syndromes such as acute myocardial infarction and unstable angina remain at risk for recurrent myocardial ischemia despite therapy with antiplatelet agents and heparin. Although first clinical trials indicate a possible use of oral direct TIs for the prevention of cardiovascular events in patients after acute myocardial infarction, the presently available data are still limited and it has not... 

Acute coronary syndromes (ACS) are a major cause of morbidity and mortality. They are characterized by intracoronary thrombus formation at the site of atherosclerotic plaques. Coronary thrombosis is the underlying mechanism in the transition from stable angina to the unstable angina (UA) syndrome, characterized by embolization of the developed thrombus and atherosclerotic plaque rupture. 

I The Clopidogrel in Unstable angina to prevent Recurrent Events (CURE) Trial Investigators. Effects of clopidogrel in addition to aspirin in patients with acute coronary syndromes without ST-segment elevation, N Engl J Med 2001 345 494-502. 

The FFtAXIS Study Group. Comparison of two treatment durations (6 days and 14 days) of a low molecular weight heparin with a 6-day treatment of unfractionated heparin in the initial management of unstable angina or non-Q-wave myocardial infarction FRAXIS (fraxiparine in acute ischaemic syndrome). Eur Heart J 1999 20 1553-1562. 

To understand the evolution of therapy of the acute coronary syndrome (ACS), which includes unstable angina, acute myocardial infarction, and interventional therapy— percutaneous coronary intervention (PCI), it is most useful to trace the historical events that provided a rationale for the use of anticoagulant and antiplatelet drugs, The focus of this chapter is upon the explosion in knowledge of the physiology of the hemostatic mechanism and will trace the rational development of therapy based upon the pathophysiology of the ACS over the past 40 years. 

Cannon CR Weintraub WS, Demopoulos LA, et al, Comparison of an early invasive and conservative strategies in patients with unstable angina coronary syndromes treated with the glycoprotein llb/llla inhibitortirofiban. N EnglJ Med 2001 344 1879-1887. 

Peters R, Mehta SR, Fox KA, et al. Clopidogrel in unstable angina to prevent recurrent events (CURE) trial investigators. Effects of aspirin dose when used alone or in combination with clopidogrel in patients with acute coronary syndromes observations from the clopidogrel in unstable angina to prevent recurrent events (CURE) study, Circulation 2003 108(14) 1682-1687. 

Platelet aggregation appears to be of pivotal importance in several acute or subacute coronary syndromes acute myocardial infarction (MI), unstable angina (UA), postangioplasty ischemia, and poststent-... 

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