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The therapy of acute myocardial infarction: current state of the art
1Center of Internal Medicine, Division of Cardiology and Pulmonology, University of Göttingen, FRG.
Insights
Early reperfusion therapy for acute myocardial infarction (AMI) using thrombolytic agents has significantly reduced mortality by dissolving coronary thrombi and salvaging ischemic heart muscle. Intravenous administration proved effective and more accessible than intracoronary methods.
Area of Science:
- Cardiology
- Emergency Medicine
- Pharmacology
Background:
- Traditional acute myocardial infarction (AMI) management focused on rest and supportive care.
- Emerging aggressive treatments for AMI emphasize limiting infarct size and left ventricular dysfunction.
- Early intervention within 3-4 hours of coronary occlusion is critical for salvaging ischemic myocardium.
Purpose of the Study:
- To review the evolution of AMI management, focusing on reperfusion strategies.
- To evaluate the efficacy of thrombolytic agents in dissolving coronary thrombi.
- To compare different routes of thrombolytic administration and their impact on patient outcomes.
Main Methods:
- Review of historical management protocols for AMI.
- Analysis of angiographic findings in early AMI cases revealing obstructive thrombi.
- Evaluation of intracoronary and intravenous thrombolytic therapies, including streptokinase and urokinase.
- Consideration of newer agents like recombinant tissue-type plasminogen activator (rt-PA).
Main Results:
- Coronary thrombi are present in approximately 80% of early AMI cases.
- Intracoronary thrombolysis achieved clot lysis in 80% of cases within 60 minutes.
- Intravenous streptokinase demonstrated a reduction in hospital mortality in large trials (ISAM and GISSI).
- Newer agents aim for targeted thrombolysis with reduced systemic effects, but require further validation.
Conclusions:
- Aggressive reperfusion therapy is key in modern AMI management.
- Intravenous thrombolytic therapy offers a more accessible and effective approach to AMI treatment.
- Ongoing research focuses on developing safer and more targeted thrombolytic agents.
Abstract:
For decades management of acute myocardial infarction (AMI) consisted of bed rest, oxygen, prevention for thromboembolic complications, and treatment of arrhythmias and heart failure. In the last years a more aggressive treatment of AMI has been developed, based on the following three basic principles: (1) Mortality of patients with AMI is determined by the infarct size and the degree of left ventricular dysfunction. (2) The time interval between the onset of coronary occlusion and any intervention to limit infarct size is brief and takes usually not more than three to four hours. (3) After the acute phase of infarction a lot of patients remain at high risk of fatal coronary events, i.e. reinfarctions. The angiographic findings during the first hours of AMI showed in about 80% of patients an obstructive coronary thrombus and led to efforts to dissolve the offending thrombi. The demonstration that coronary thrombi can be lysed in about 80% of cases within 60 minutes after the intracoronary injection of thrombolytic agents (streptokinase or urokinase) has boosted the reperfusion therapy in AMI in the hope that ischemic myocardium might be salvaged. Intracoronary infusion of thrombolytic agents however, can be applied only in a minority of patients with AMI because coronary angiography and a skilled team of investigators are required, therefore a short-time intravenous high dose streptokinase infusion was developed. In the meantime two large double blind randomized trials (ISAM and GISSI) could demonstrate a reduction in hospital mortality in AMI especially by early treatment with intravenous streptokinase. Conventional thrombolytic agents produce a systemic lytic state with the possibility of hemorrhage, therefore recombinant tissuetype plasminogen activator (rt-PA) and two other drugs, acylated streptokinase and pro-urokinase, were developed with the aim of inducing coronary thrombolysis without severe systemic lytic state, but the efficacy of these new drugs remains to be demonstrated in randomized trials versus conventional thrombolytic agents.(ABSTRACT TRUNCATED AT 250 WORDS)