A Prospective Analysis on the Expansion Rates of Abdominal Aortic Aneurysms

Summary

Participation Requirements

Description

Abdominal aortic aneurysm (AAA) is an asymptomatic problem until rupture occurs, causing excruciating pain and sudden death. It is diagnosed typically by ultrasound when the aortic diameter is ? 3.0 cm and an aortic diameter ? 5.5 cm generally requires surgical repair to prevent rupture. A normal ao...

Abdominal aortic aneurysm (AAA) is an asymptomatic problem until rupture occurs, causing excruciating pain and sudden death. It is diagnosed typically by ultrasound when the aortic diameter is ? 3.0 cm and an aortic diameter ? 5.5 cm generally requires surgical repair to prevent rupture. A normal aorta is 2.0 cm in diameter. For patients with small AAA (3.0-5.4 cm) serial imaging studies is recommended along with risk factor modification. However, follow up ultrasound protocols are difficult to follow, resulting in many patients with expanding AAA not being detected until too late. To streamline and better identify patients with small AAAs at risk for expansion, the investigators look to RhoA as a possible biomarker. The investigators will recruit within a 3-year period a total of 200 subjects diagnosed with small AAA 3.0-5.4 cm diameter from the VA Northern California Health Care System. All subjects enrolled will already have a baseline aortic diameter established at the time of initial AAA screening or diagnostic imaging. The investigators expect the follow up ultrasound measurement for this study will be at least 1 to 5 years after their baseline ultrasound study. The follow up evaluation will then assess expansion rates of the aorta. Stable aorta subjects will have an expansion rate of less than 0.2 cm/year and expanding aorta subjects will have an expansion rate ? 0.2 cm/year as based on preliminary data. After the ultrasound, 30 ml of blood will be drawn into heparinized tubes and undergo blood analysis for the RhoA protein in monocytes. All patients will be notified of the possible need to return back for either clinical reason: AAA greater than 5.5 cm or research protocol reasons: inadequate monocyte collection or changing clinical data requirements. Cardiovascular risk factors will also be collected. All collected data between stable and expanding AAA groups will then be compared for analysis. If biological or clinical risk factors are identified as reliable biomarkers for AAA expansion, then AAA screening programs could be modified to increase screening yield and improve surveillance for small AAAs. Additionally, novel diagnostic techniques could be developed to better identify small AAA patients at risk for surgery.

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