Date of Award

January 2012

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

John A. Elefteriades

Subject Area(s)

Medicine

Abstract

Previous evaluation of total aortic calcium score suggests that mutations promoting ascending aortic aneurysm development may protect against atherosclerosis. However, calcium score is a late indicator for atherosclerosis. We evaluated carotid intima media thickness (IMT), an earlier indicator, to assess the degree of atherosclerosis in ascending aortic aneurysm patients compared to controls.

Images of the right and left common carotid arteries were obtained in 52 patients with ascending aortic aneurysms and 29 controls using a Sonosite MicroMaxx portable ultrasound. The IMT was measured with Sonosite Sonocalc IMT software, a computer based algorithm with manual override. Six IMT measurements were obtained for each patient (right and left proximal, mid, and distal common carotid arteries) by a single observer and averaged. A multiple linear regression analysis was applied to test for an association between aneurysm and carotid IMT.

Patients with ascending aortic aneurysms had 0.131mm lower carotid IMT values compared to patients in the control group (p = 0.0002) independent of risk factors for atherosclerosis (age, BMI, gender, family history, smoking, dyslipidemia, race, diabetes, HTN). Age increased the IMT significantly by 0.005mm (p = 0.0003) per year. There was no significant difference in age between the two groups. BMI, male gender, positive family history, dyslipidemia, diabetes, and HTN also increased the IMT, but were not statistically significant.

This investigation provides further evidence that ascending aortic aneurysm provides protection against atherosclerosis, supporting the idea that pro-aneurysmal genetic mutations are also anti-atherogenic - a "silver lining" in the cloud of aneurysm disease.

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