Clinical Trial: A Prospective Analysis on the Expansion Rates of Abdominal Aortic Aneurysms

Study Status: Enrolling by invitation
Recruit Status: Enrolling by invitation
Study Type: Observational

Official Title: A Prospective Analysis on the Expansion Rates of Abdominal Aortic Aneurysms

Brief Summary:

Abdominal aortic aneurysm (AAA) disease is an abnormal bulging of the main abdominal artery, which is the called the abdominal aorta. The purpose of this observational study is to identify whether a blood biomarker protein RhoA can predict which small AAA patients may need surgery in the future.

Participating patients will receive an ultrasound and blood draw. The patients will be divided into expanding and stable aorta groups after determining each patient's aortic expansion rate. The blood RhoA levels and aortic expansion rates between both groups would then be compared to look for any relationships.


Detailed Summary:

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 2-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 expand
Sponsor: VA Northern California Health Care System

Current Primary Outcome: Aortic Expansion Rate [ Time Frame: Immediately after study ultrasound for each subject. The aortic expansion rate is immediately obtained once the study ultrasound measurement of the aortic diameter is verified. ]

Aortic expansion rate (cm/yr) is calculated by taking the difference of aortic growth (cm) divided by the number of days between a patient's screening date and the study date. This rate is then converted into cm/yr.


Original Primary Outcome: Same as current

Current Secondary Outcome: RhoA levels [ Time Frame: From collection of blood to completion of blood analysis. This analysis takes 5-7 days to complete per patient. ]

RhoA levels measured in fluorescent units from patient monocytes will be determined


Original Secondary Outcome: Same as current

Information By: VA Northern California Health Care System

Dates:
Date Received: October 6, 2015
Date Started: September 2015
Date Completion: September 2017
Last Updated: April 18, 2017
Last Verified: April 2017