Subclinical coronary atherosclerosis ups risk for myocardial infarction

Subclinical, obstructive coronary atherosclerosis contributes to a more than eightfold increase in the risk for myocardial infarction among asymptomatic individuals, a study has shown.

A total of 9,533 asymptomatic persons aged 40 years or older with no known ischaemic heart disease in Denmark were included in this prospective observational cohort study. The investigators assessed subclinical coronary atherosclerosis using coronary computed tomography angiography conducted blinded to both treatment and outcomes.

Coronary atherosclerosis was described based on luminal obstruction (nonobstructive or obstructive; ≥50-percent luminal stenosis) and extent (nonextensive or extensive; one-third or more of the coronary tree). Myocardial infarction was the primary outcome, and a composite of death or myocardial infarction served as secondary outcome.

Of the participants, 5,114 (54 percent) had no subclinical coronary atherosclerosis, 3,483 (36 percent) had nonobstructive disease, and 936 (10 percent) had obstructive disease. Over a median 3.5 years of follow-up, 193 persons died and 71 had myocardial infarction.

Individuals with obstructive (adjusted relative risk [aRR], 9.19, 95 percent confidence interval [CI], 4.49‒18.11) and extensive disease (aRR, 7.65, 95 percent CI, 3.53‒16.57) were at greater risk for myocardial infarction. Those with obstructive-extensive subclinical coronary atherosclerosis (aRR, 12.48, 95 percent CI, 5.50‒28.12) or obstructive-nonextensive disease (aRR, 8.28, 95 percent CI, 3.75‒18.32) had the highest risk for myocardial infarction.

In addition, a higher risk for the composite endpoint of death or myocardial infarction was observed in participants with extensive disease, irrespective of the degree of obstruction: nonobstructive-extensive (aRR, 2.70, 95 percent CI, 1.72‒4.25) and obstructive-extensive (aRR, 3.15, 95 percent CI, 2.05‒4.83).

Notably, the study was limited by the inclusion of mostly White persons.