Infections Associated with Coronary Artery Disease Risk
Several chronic infections pose a significant risk for coronary artery disease, with the strongest evidence supporting Helicobacter pylori, Chlamydia pneumoniae, and cytomegalovirus, while acute infections like influenza and HIV also increase cardiovascular risk. 1
Chronic Infections with Strong Evidence
Bacterial Infections
Helicobacter pylori demonstrates a strong association with atherosclerosis and coronary artery disease, though the relationship may be partially confounded by traditional risk factors 1, 2, 3
Chlamydia pneumoniae shows the strongest evidence among bacterial infections, with the organism identified directly in atherosclerotic coronary plaques and elevated antibody levels correlating with increased coronary events 1, 4, 2
- Periodontal bacterial DNA (P. gingivalis, A. actinomycetemcomitans, P. intermedia, T. forsythensis) was detected in 60% of atherosclerotic coronary arteries but absent in non-atherosclerotic internal mammary arteries 4
- The combined effect of high Chlamydia pneumoniae antibodies with elevated hs-CRP (≥2 mg/L) increases coronary risk 5.4-fold compared to those with low antibody levels and low CRP 5
Periodontal infections (chronic periodontitis) contribute to coronary artery disease risk, likely through cumulative infectious burden rather than as a single causative agent 1, 6
Viral Infections
Cytomegalovirus (CMV) demonstrates strong association with atherosclerosis, detected in 66.7% of atherosclerotic coronary arteries and 46.7% of non-atherosclerotic vessels 1, 4, 2, 3
Herpes simplex virus type 1 (HSV-1) significantly increases coronary risk, particularly when combined with elevated inflammation markers—subjects with high HSV-1 antibodies and high CRP show a 25.4-fold increased risk 5
HIV infection increases coronary artery disease risk beyond traditional cardiovascular risk factors, with women experiencing up to twice the risk compared to men 1
SARS-CoV-2 (COVID-19) is associated with cardiovascular complications, though long-term coronary artery disease risk remains under investigation 1
Acute Infections
- Influenza increases short-term cardiovascular risk through mechanisms including procoagulant acute-phase reactant induction and atherosclerotic plaque destabilization 1
- Hospitalization for acute infection represents a short-term stroke and cardiovascular risk factor 1
- Antiviral treatment within 2 days of influenza diagnosis reduces stroke/TIA risk by 28% (HR 0.72,95% CI 0.62-0.82) over 6 months 1
- Annual influenza vaccination reduces stroke risk by 65% (HR 0.35,95% CI 0.27-0.45) in adults >65 years 1
Cumulative Infectious Burden Concept
Multiple simultaneous chronic infections (infectious burden) may be more important than any single pathogen in promoting atherosclerosis—the combined effect of H. pylori gastric infection, C. pneumoniae bronchitis, and periodontitis likely exceeds individual contributions 1, 6
The joint effect of HSV-1 and Chlamydia pneumoniae infections is nearly additive, with each increasing risk independently of the other 5
Critical Clinical Caveat
Despite strong epidemiological associations, randomized trials of antibiotic therapy have consistently failed to demonstrate benefit in preventing cardiovascular endpoints, including in secondary prevention of coronary disease. 1 This suggests that while infections may contribute to atherosclerosis initiation or progression, eradicating established infections does not reverse cardiovascular risk.
Inflammation as the Common Pathway
Chronic infections promote atherosclerosis through inflammatory mechanisms rather than direct vascular damage 1
The effect of chronic infections is amplified in patients with elevated inflammatory markers—high hs-CRP (≥2 mg/L) combined with high infectious antibody titers substantially increases coronary risk compared to either factor alone 5
Patients with chronic inflammatory diseases (rheumatoid arthritis, systemic lupus erythematosus) should be considered at increased stroke and coronary risk (Class I, Level of Evidence B) 1