Should Acute MI Patients Receive Dual Antiplatelet Therapy
Should Acute MI Patients Receive Dual Antiplatelet Therapy
Thrombolytic therapy in the management of acute myocardial infarction (MI) shows true evidence of benefit. Administration of a thrombolytic saves about 30 lives per 1,000 in those presenting within six hours of symptom onset but only 20 lives per 1,000 when patients receive treatment between six and 12 hours after symptom onset. After 12 hours there appears to be only a small and statistically uncertain benefit.
The aim in thrombolysis should be to increase the number of patients who achieve TIMI grade 3 flow as soon as possible after the occlusive event. Additional benefit in improving thrombolysis, particularly in reducing 30-day mortality, has been shown by adding the antiplatelet agent, aspirin, to thrombolytic therapy. The addition of a second antiplatelet agent, such as clopidogrel, has been shown to be of benefit in other, less immediately severe atherothrombotic manifestations (unstable angina and non-ST-elevation MI) and looks to be a promising development in the management of acute ST-elevation MI. The potential advantages of dual antiplatelet therapy in this setting, investigated in the recently published CLARITY study, are discussed.
More than a quarter of a million people each year in the UK suffer a myocardial infarction (MI). Many die within the first two hours and at least half have succumbed within a month. Even for those who survive the first month, there is an above average risk of dying within the next five to 10 years, from recurrent MI or other problems related to the underlying cause. Acute MI is essentially a thrombotic event with the development of occlusive clot following the disruption of the atheromatous plaque. The key to optimal initial management of acute MI is to ensure that the blood flow is reinstated to the affected, infarcting myocardium, using treatments that dissolve clot. The introduction of thrombolytic therapy in the 1980s was a major step forward in the management of these patients, reducing mortality to between 10 and 20%. However, a substantial number of patients receiving fibrinolytic therapy do not achieve adequate reperfusion and, even in those whose arteries are unblocked, reocclusion can occur. In these patients, the long-term mortality risk is doubled.
Abstract and Introduction
Abstract
Thrombolytic therapy in the management of acute myocardial infarction (MI) shows true evidence of benefit. Administration of a thrombolytic saves about 30 lives per 1,000 in those presenting within six hours of symptom onset but only 20 lives per 1,000 when patients receive treatment between six and 12 hours after symptom onset. After 12 hours there appears to be only a small and statistically uncertain benefit.
The aim in thrombolysis should be to increase the number of patients who achieve TIMI grade 3 flow as soon as possible after the occlusive event. Additional benefit in improving thrombolysis, particularly in reducing 30-day mortality, has been shown by adding the antiplatelet agent, aspirin, to thrombolytic therapy. The addition of a second antiplatelet agent, such as clopidogrel, has been shown to be of benefit in other, less immediately severe atherothrombotic manifestations (unstable angina and non-ST-elevation MI) and looks to be a promising development in the management of acute ST-elevation MI. The potential advantages of dual antiplatelet therapy in this setting, investigated in the recently published CLARITY study, are discussed.
Introduction
More than a quarter of a million people each year in the UK suffer a myocardial infarction (MI). Many die within the first two hours and at least half have succumbed within a month. Even for those who survive the first month, there is an above average risk of dying within the next five to 10 years, from recurrent MI or other problems related to the underlying cause. Acute MI is essentially a thrombotic event with the development of occlusive clot following the disruption of the atheromatous plaque. The key to optimal initial management of acute MI is to ensure that the blood flow is reinstated to the affected, infarcting myocardium, using treatments that dissolve clot. The introduction of thrombolytic therapy in the 1980s was a major step forward in the management of these patients, reducing mortality to between 10 and 20%. However, a substantial number of patients receiving fibrinolytic therapy do not achieve adequate reperfusion and, even in those whose arteries are unblocked, reocclusion can occur. In these patients, the long-term mortality risk is doubled.
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