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Infection as a risk factor for infarction and atherosclerosis
1Second Department of Medicine, Helsinki University Central Hospital, Finland.
Abstract:
A growing amount of clinical and experimental evidence suggests a link between infection and atherosclerotic diseases including both myocardial and cerebral infarction. A prime example is a greatly increased risk of stroke in septicaemic patients with and without endocarditis. Controlled clinical studies have recently shown, however, that certain other milder bacterial infections are also a risk factor for infarction. A preceding febrile respiratory infection was a major risk factor for stroke in young and middle aged patients. In patients with acute myocardial infarction Chlamydia pneumoniae and dental infections seem to be risk factors according to one controlled clinical study. Several possible mechanisms could explain the observed association of infection and infarction. For instance, infection causes a hypercoagulable state which increases the risk of thrombosis. In addition, infection has profound and harmful effects on prostaglandin and lipid metabolism. Infection may also have some role in the atherosclerotic process itself by inducing damage and inflammation in vascular endothelium in the presence of hypercholesterolemia. So far, however, little clinical evidence is available to suggest that by controlling infection the risk of infarction or development of atherosclerotic lesions might be reduced except in patients with endocarditis, where the risk of thromboembolic complications rapidly diminished when the infection is controlled with antimicrobial therapy.
Insights
Infections, including respiratory and dental, increase the risk of stroke and myocardial infarction. Controlling infections, particularly endocarditis, may reduce associated thromboembolic complications.
Area of Science:
- Cardiovascular Medicine
- Infectious Diseases
- Pathology
Background:
- Growing evidence links infections to atherosclerotic diseases like myocardial and cerebral infarction.
- Septicemia and endocarditis significantly elevate stroke risk.
- Milder bacterial infections, such as febrile respiratory infections and Chlamydia pneumoniae, are also identified as infarction risk factors.
Purpose of the Study:
- To explore the association between various infections and the risk of atherosclerotic events.
- To investigate potential mechanisms linking infection to infarction.
- To assess the impact of infection control on infarction risk and atherosclerotic lesion development.
Main Methods:
- Review of clinical and experimental evidence.
- Analysis of controlled clinical studies identifying risk factors for stroke and myocardial infarction.
- Examination of proposed pathogenetic mechanisms.
Main Results:
- Febrile respiratory infections are a major stroke risk factor in younger and middle-aged individuals.
- Chlamydia pneumoniae and dental infections are implicated as risk factors for acute myocardial infarction.
- Infection can promote thrombosis, alter lipid/prostaglandin metabolism, and induce vascular inflammation.
Conclusions:
- Infections are linked to increased risk of infarction and atherosclerosis.
- Mechanisms include hypercoagulability, metabolic disturbances, and endothelial inflammation.
- Controlling infection may reduce infarction risk, notably in endocarditis patients where thromboembolic complications diminish with antimicrobial therapy.