Elevated TMAO predicts cardiovascular events after acute coronary syndromes

Last Updated: 2017-01-18

By Will Boggs MD

NEW YORK (Reuters Health) - Elevated gut microbiota-dependent trimethylamine N-oxide (TMAO) levels are associated with an increased risk of major adverse cardiac events in acute coronary syndrome (ACS) patients, researchers report.

"Physicians have to know that beyond traditional risk factors novel metabolites from the microbiome affect our body and in turn our health - this is now particularly impressive after ACS," Dr. Thomas F. Luescher from University Hospital Zurich, Switzerland told Reuters Health by email.

Previous research has revealed an association between systemic TMAO levels and cardiovascular risks in a variety of settings, but this relationship has not been examined in individuals with ACS.

Dr. Luescher and colleagues investigated the possible relationship between systemic levels of TMAO and incident major adverse cardiovascular events (MACE, including myocardial infarction, stroke, need for revascularization, or death) and mortality among individuals presenting with ACS at the Cleveland Clinic (n=530) and at University Hospital Zurich (n=1683).

In the Cleveland cohort, the frequency of experiencing a MACE at 30 days and 6 months following presentation increased with increasing quartiles of TMAO levels. Compared with patients in the lowest quartile of TMAO levels, those in the highest quartile were 2.29-fold more likely to experience MACE at 30 days and 2.48-fold more likely to experience MACE at 6 months, according to the January 11th European Heart Journal online report.

The 7-year mortality risk was 3.72-fold higher among patients in the highest quartile of TMAO levels.

Inclusion of TMAO as a variable resulted in a significant improvement in risk estimation over traditional risk factors for 30-day and 6-month MACE, as well as for 7-year mortality.

Results were similar in the subset of patients who were initially negative for troponin T at presentation.

In the Swiss ACS cohort, higher levels of TMAO were significantly associated with higher risks of 1-year MACE and 1-year mortality.

"The fact that the microbiome in our body provides metabolites that affect outcome in ACS beyond current risk factors is certainly important," Dr. Luescher said. "Furthermore, it is of interest that the U.S. patients had higher levels of TMAO than the Swiss ones, possibly due to different diets."

"The importance of our findings is underlined by the modifiable nature of TMAO, both with diet and with potential therapeutics under development, offering new prospects for treatment strategies at both levels of primary and secondary prevention," the researchers conclude.

SOURCE: http://bit.ly/2jM52PZ

Eur Heart J 2017.