Anticoagulant Therapy in Acute Coronary Syndrome

Abstract

The term acute coronary syndrome( ACS) is used to cover a group of clinical symptoms compatible with acute myocardial ischemia that result from coronary artery diseases.These include unstable angina (UA) and the closely related non–ST-segment elevation myocardial infarction (NSTEMI), which are associated with an increased risk of death and myocardial infarction (MI); and ST-segment elevation myocardial infarction (STEMI). The course of recovery in (ACS) involves spontaneous, mechanical, or pharmacologic thrombolysis. Clotlysis is associated with hypercoagulability, as thrombin molecules are exposed during the process. This sets the stage for recurrent thrombosis and possible vessel reocclusion. For this reason, anticoagulant therapy is critical during the acute phase of treatment. In patients with non-ST elevation acute coronary syndrome (ACS), which includes unstable angina and non-ST elevation myocardial infarction (NSTEMI) anticoagulant therapy is made for patients irrespective of whether an invasive or a conservative approach is taken. Anticoagulant therapy should be given as soon as possible after diagnosis and should be given in conjunction with recommended antiplatelet therapy.For patients managed with an early invasive strategy (angiography within 4 to 48 hours), suggestion with bivalirudin or unfractionated (UFH) as opposed to enoxaparin or to fondaparinux When fondaparinux is chosen, (UFH) (or bivalirudin) should be given before percutaneous coronary intervention. For patients who will be referred to the catheterization laboratory within four hours (usually due to patient instability for reasons such as refractory angina, heart failure, arrhythmia, or hemodynamic instability), suggestion with (UFH) or bivalirudin as opposed to fondaparinux or enoxaparin. For patients in whom a conservative (non-invasive) strategy is planned,recommend either fondaparinux or enoxaparin in preference to either unfractionated heparin or bivalirudin . The choice between fondaparinux and enoxaparin should be guided by issues of cost and local practice. For patients at higher risk of bleeding , fondaparinux is suggested. All patients with ST-elevation myocardial infarction (STEMI) should receive anticoagulation. Irrespective of the reperfusion strategy, anticoagulant therapy should be given as soon as possible after diagnosis. In addition, all patients with (STEMI) should receive dual antiplatelet therapy. For all patients treated with primary percutaneous coronary intervention, anticoagulant therapy is recommended. Recommendation with either bivalirudin (with provisional glycoprotein [GP] IIb/IIIa inhibitor incases of ischemic complications or large thrombus burden) or a heparin (and planned GP IIb/IIIa inhibitor) in preference to fondaparinux. ` Suggestion with bivalirudin in preference to a heparin (used in conjunction with a GP IIb/IIIa inhibitor). This recommendation takes into account the opposing outcomes of major bleeding and stent thrombosis, as well as equivalent or better mortality with bivalirudin. For patients in whom bivalirudin will not be chosen, enoxaparin, is a reasonable alternative to (UFH) for patients undergoing( PCI) . ` For patientstreated with fibrinolytic therapy, anticoagulant therapy is recommended . For patients not at high risk of bleeding, suggesstion using enoxaparin as opposed to( UFH), fondaparinux, or bivalirudin. For those patients in whom (PCI) is possible or likely after fibrinolytic therapy, (UFH) is a reasonable choice. For patients at high risk of a bleeding complication and who are not likely to require (PCI), suggestion with fondaparinux as opposed to enoxaparin or (UFH).