Ascending thoracic aortic aneurysms protect against myocardial infarctions

Abstract

There has been increasing evidence that ascending thoracic aortic aneurysms (TAAs) protect against atherosclerosis. However, there have been no studies examining the relationship between ascending TAAs and clinical endpoints of atherosclerosis, such as stroke or peripheral arterial disease. In this study, we aim to characterize the relationship between TAAs and a specific clinical endpoint of atherosclerosis, myocardial infarction (MI). We compared prevalence of coronary artery disease (CAD) and MIs in 487 patients who underwent surgical repair for ascending TAAs to 500 control patients who did not have an ascending TAA. Multivariate binary logistic regression was used to calculate the odds of having MI if a patient had an ascending TAA versus any of several MI risk factors. There was a significantly lower prevalence of CAD and MI in the ascending TAA group than in the control TAA group. The odds of having a MI if a patient had a MI risk factor were all > 1 (more likely to have a MI), with the lowest statistically significant odds ratio being 1.54 (age; p = 0.001) and the highest being 14.9 (family history of MI; p < 0.001). The odds ratio of having a MI if a patient had an ascending TAA, however, was near 0 at 0.05 (p < 0.001). This study provides evidence that ascending TAAs protect against MIs, adding further support to the hypothesis that ascending TAAs protect against atherosclerotic disease.

Keywords: acute coronary syndrome; aneurysm; atherosclerosis; cardiovascular risk factors; coronary artery; infarction; myocardial infarction.

Fig. 1

Prevalence of coronary artery disease and myocardial infarctions. There was a significantly lower prevalence of CAD and MIs in the aneurysm group than in the control group. There were 61 patients in the aneurysm group who had CAD (p < 0.001) versus 140 in the control group. There were 11 patients in the aneurysm group who have had a MI versus 83 in the control group (p < 0.001). CAD, coronary artery disease; MI, myocardial infarction.

Fig. 2

Likelihood of having a myocardial infarction. The odds ratio of having a MI when a patient had an ascending TAA versus MI risk factors. Age is in 10-year intervals and BMI is in 10-unit intervals. Note the drastic difference in odds ratios when a patient had an ascending TAA compared with when a patient had a MI risk factor. *Statistically significant (p <0.05). BMI, body mass index; MI, myocardial infarction; TAA, thoracic aortic aneurysm.