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Thrombosis and embolism from cardiac chambers and infected valves
Insights
Anticoagulation effectively reduces embolism risk in acute myocardial infarction and dilated cardiomyopathy. However, it is generally not recommended for chronic left ventricular aneurysm or native valve endocarditis.
Area of Science:
- Cardiology
- Thrombosis and Embolism
Background:
- Cardiac conditions like myocardial infarction, aneurysm, cardiomyopathy, endocarditis, and atrial fibrillation carry a risk of embolism.
- Warfarin-based anticoagulation is effective in some cases, but the role of antiplatelet agents is not well-established.
- Mural thrombus is a common factor in thromboembolism for myocardial infarction, aneurysm, and cardiomyopathy, detectable via echocardiography and scintigraphy.
Purpose of the Study:
- To review the role of antithrombotic therapy in various cardiac conditions associated with embolic risk.
- To clarify the indications and contraindications for anticoagulation and antiplatelet agents in these conditions.
Main Methods:
- Review of existing evidence on anticoagulation and antiplatelet therapy in specific cardiac conditions.
- Analysis of embolic risk factors and diagnostic modalities for mural thrombus.
- Evaluation of treatment strategies based on condition, risk, and potential complications.
Main Results:
- Moderate-intensity anticoagulation reduces embolism in extensive myocardial infarction; discontinuation after 8-12 weeks is usually safe.
- Anticoagulation is generally inappropriate for chronic left ventricular aneurysm due to low embolic risk.
- Dilated cardiomyopathy carries a high embolic risk, often warranting moderate-intensity anticoagulation.
- Anticoagulation is not recommended for native valve endocarditis due to high hemorrhage risk and unclear efficacy.
- Anticoagulant therapy should be continued cautiously in prosthetic valve endocarditis due to high embolic risk and cerebral hemorrhage risk.
- Nonvalvular atrial fibrillation requires further trials to determine antithrombotic therapy needs for different patient subsets.
Conclusions:
- Antithrombotic therapy decisions must be individualized based on the specific cardiac condition and embolic risk.
- Anticoagulation is beneficial in acute myocardial infarction and dilated cardiomyopathy but not typically indicated for chronic left ventricular aneurysm or native valve endocarditis.
- Further research is needed to establish optimal antithrombotic strategies for nonvalvular atrial fibrillation and other complex cardiac scenarios.
Abstract:
In a number of cardiac conditions (acute myocardial infarction, chronic left ventricular aneurysm, dilated cardiomyopathy, infective endocarditis and atrial fibrillation in the absence of valvular disease), the risk of embolism gives cause for concern. Although anticoagulation with warfarin (Coumadin)-derivatives has been shown to be effective in some of these situations, there is no evidence regarding the role of antiplatelet agents. The common factor in the thromboembolic potential of acute myocardial infarction, chronic left ventricular aneurysm and dilated cardiomyopathy is mural thrombus. This can be detected by two-dimensional echocardiography and indium-111 platelet scintigraphy. Although of value in elucidating the natural history of mural thrombus, in most cases, management is not substantially aided by these investigations. In patients with extensive myocardial infarction, particularly anterior infarction, moderate intensity anticoagulation started soon after hospital admission reduces the rate of embolism. After 8 to 12 weeks, embolic risk is low so that anticoagulants can usually be discontinued. Patients with chronic left ventricular aneurysm have a low incidence of embolism; anticoagulation is, therefore, inappropriate. Dilated cardiomyopathy is associated with a high risk of embolism; moderate intensity anticoagulation may be advisable in many such cases. Little information is available regarding the incidence of thromboembolism or the role of antithrombotic therapy in the patient with a diffusely dilated left ventricle due to ischemic heart disease. In native valve infective endocarditis, the risk of hemorrhage is high, and the efficacy of conventional anticoagulants unclear; thus, anticoagulation should not be instituted for the cardiac condition as such. However, in prosthetic valve endocarditis, the risk of embolism seems to be very high, and anticoagulant therapy should be continued, but with great care because there is a substantial risk of cerebral hemorrhage. Atrial fibrillation in patients with valvular heart disease is dealt with in a previous review. Patients with nonvalvular atrial fibrillation are at varying risk of embolism, depending on the etiology of the arrhythmia; trials of antithrombotic therapy are needed for the various subsets of patients. In most elderly patients, the etiology is not known, and their stroke risk is high. The risk of embolism in younger patients with idiopathic atrial fibrillation is so low as to make any antithrombotic therapy unnecessary.(ABSTRACT TRUNCATED AT 400 WORDS)