US study to determine if imaging can detect subclinical cardiovascular
!8 September 2007
One of the most challenging aspects of cardiovascular
imaging is going to be how to detect subclinical atherothrombosis disease in
order to address earlier management. The High Risk Plaque (HRP) study will
approach this challenge clinically and economically with a multimodality
In recent years, the concept of multimodality imaging has emerged at the
same time as advances in the newer technologies of cardiac magnetic
resonance (CMR) and coronary computed tomography (CCT).
hybrid imaging yielding fused images of the heart and blood vessels use
several of the imaging technologies simultaneously, such as with PET-CT and
SPECT-CT. Within this context, the clinician has to be aware of this rapidly
evolving field and to adhere to updated guidelines.
The HRP BioImage Study
is a study of the characteristics of subclinical cardiovascular disease, as
measured by imaging modalities, circulating biomarker measurements, and risk
factors that predict progression to overt clinical cardiovascular disease,
in a diverse, population-based sample of 7,300 men (aged 55-80) and women
The study population aims to mirror the sociodemographics of the US
population as a whole, with approximately 69% percent of the cohort being
white, 12% percent African-American, 13% percent Hispanic, 4% percent Asian,
predominantly of Chinese descent, and 2% other (US Census Bureau: 2000).
The cohort will be recruited from the Humana Health Plan membership
represented in three major US markets: Chicago, IL, Louisville, KY and
Southern FL. Of the 7300 participants, 6000 will be characterized with
respect to their Framingham risk score and various imaging features
including carotid and coronary calcification, carotid intimal-medial wall
thickness and presence of echogenic lucencies and lower extremity vascular
insufficiency as determined by the ankle brachial index.
Blood samples will be assayed for putative biochemical risk factors using
both an unsupervised proteomic and metabolomic profiling of plasma and
targeted assays for particular analytes. In addition, samples will be banked
for additional follow-on studies.
Participants will be followed for identification and characterization of
cardiovascular disease events, including acute myocardial infarction and
other forms of coronary heart disease (CHD), and stroke; mortality; and for
cardiovascular disease interventions. The remaining 1,300 subjects will be
evaluated and followed in a similar manner except no imaging studies will be
The study will be conducted using an innovative infrastructure
and method of participant recruitment and enrollment. Mobile laboratories
containing the imaging equipment will travel to the three markets included
in the study. Participants will be recruited based on claims monitoring to
pre-determine eligibility. The baseline examinations of the 7300
participants will occur over a 12-month period.
Based on particular findings, (CACS, IMT, ABI and presence of aortic
aneurysm), approximately 2,000 participants of the 6,000 imaging cohort will
be referred for higher resolution imaging modalities to better characterize
their arterial disease. This additional imaging will also be conducted on
the mobile laboratories and occur during the same 12-month period.
Participants will be contacted every 6 months throughout the 3 year study to
assess cardiovascular events, clinical morbidity and mortality, and to
obtain additional blood samples.
In summary, A critical issue for the
clinician and for society is the following: can imaging technology detect
subclinical cardiovascular disease and, as a result, fostering earlier
management to promote health and at a lower cost?
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