Imaging is Everything: What The Clinician Needs To Know

Basic Science Track: Current understanding of high-risk atherosclerosis-160003

Vienna, Austria, 4 September 2007:

In recent years, the concept of multimodality imaging has emerged coincident with advances in the newer technologies of Cardiac Magnetic Resonance (CMR) and Coronary Computed Tomography (CCT). It has become clear that the field of cardiovascular imaging, in general, is enjoying major growth and technological advances. Multimodality and 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.

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 HRP (High Risk Plaque) study will approach this challenge clinically and economically with a multimodility approach. Specifically, 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 (aged 60-80). The sociodemographics of the study population aims to mirror the US population as a whole with approximately 69% percent of the cohort will be white, 12% percent African-American, 13% percent Hispanic, 4% percent Asian, predominantly of Chinese descent and 2% other (U.S. 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 conducted.

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?