Bacteria in plaque may increase risk for heart attacks

August 29, 2017

In one study researchers looked at 150 individuals with periodontal diseases and found that the total number of periodontal bacteria in subgingival plaques was higher in individuals that have suffered from an acute myocardial infarction (heart attack). The second study found that the same DNA from different kinds of periodontal bacteria in plaque was also in the patients' heart arteries. Researchers believe that these findings may help substantiate what they have long known; if there is a sterile pathway, such as a bloodstream, near a periodontally infected area that the bacteria from this infected area cause inflammation in the gums that opens up pores in the surrounding blood vessels, which enables the bacteria to enter the bloodstream and travel to other parts of the body and cause great harm.

"It is like setting up a garbage dump on the edge of a river. You wouldn't be surprised if the lake downstream ended up polluted with the garbage from the dump," said Vincent J. Iacono, DMD and president of the American Academy of Periodontology. "A patient's bloodstream acts very much like the river in this analogy, in that it carries the bacteria from the periodontal plaques, possibly 'polluting' the arteries of the heart with periodontal bacteria, causing inflammation of the arteries which may lead to a heart attack. This potential effect of periodontal bacteria further supports the need for periodic deep cleanings to enhance overall health and wellbeing."

These studies represent two in a large body of research that investigates the possible link between periodontal diseases and other systemic conditions such as heart disease. "Intervention data is not available to prove a causal relationship between the two. Right now we are currently advising patients that maintaining good periodontal health can only help not hurt," said Iacono.


Cystatin-C is FDA-approved for diagnostic use, but the test is not yet widely available or commonly used in clinical settings. This and other studies have shown that cystatin-C may detect moderate kidney disease at earlier stages, before creatinine levels would rise, enabling identification of a much larger group of people at risk for death and cardiovascular complications.

"Our results show that a normal creatinine is not nearly as reassuring as we used to believe. In persons at a high risk for kidney disease, such as an older person or one with diabetes, hypertension, or cardiovascular disease, a normal creatinine level may be misleading us into thinking that the patient is safe from the cardiovascular effects of kidney disease," said the study's lead author Michael Shlipak, M.D. M.P.H, of University of California at San Francisco.

Dr. Shlipak noted that additional research is needed to determine the exact clinical role for this test, but that it may be most useful in high-risk patients with normal creatinine. Evaluating the mechanisms that underlie this strong association between the kidney and cardiovascular disease would be critical for targeting prevention efforts, he said.

Participants in the Cardiovascular Health Study were aged 65 or older at baseline. Their creatinine and cystatin-C measures were taken in 1992 or 1993 and the average follow-up period was 7.4 years. The study sites were Forsyth County, North Carolina, Sacramento County, California, Washington County, Maryland and the city of Pittsburgh.


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