Advances in diagnostic imaging with expensive technologies and reimbursement policies that favor illness intervention rather than primary and secondary prevention have resulted in rising costs of health care and more people being deprived of its benefits (Sultz 2004, Bodenheimer 2002).
In the field of coronary artery disease (CAD) are several non-invasive imaging techniques for diagnostic and risk stratification purposes such as echocardiography, perfusion imaging (cardiac stress SPECT - single photon emission computed tomography - and stress PET - positron emission tomography), non-invasive cardiac computed tomography angiography (CTA) and combined perfusion-anatomy (PET-CT) studies. There are an estimated 40 million noninvasive cardiac tests performed each year (Mark DB 2003). For echocardiography and SPECT imaging, reimbursement from Medicare encompasses approximately 30% of all payments, totaling over $1 billion in the year 2000 (ACC 2003). There are, however, basic questions about cardiovascular imaging techniques that need to be addressed: how does technology benefit the patient? It is worth the cost? Is treatment plan enhanced? Is outcome better? Data are necessary for addressing these questions and if appropriate for acceptance among practicing physicians, patients and third party insurers.
The relevance of the proposed study, the CENTURY trial, lies in its original design, testing the impact of stress perfusion imaging by PET coupled with two different intensities of clinical management strategies (standard or comprehensive respectively). This study will examine post-test resource utilization and reduction of cardiovascular risk in patients with known disease or at high risk for CAD.
There will be a total of 1300 men and women enrolled with approximately 650 subjects randomized to one of two treatment arms. Eligible patients must have clinical indications for stress perfusion testing.
Following confirmation of eligibility and provision of signed informed consent, patients will be randomized to one of the two possible treatment strategies. At time of randomization patients will be assigned to "PET guided + comprehensive" versus "standard medical treatment."
Patients of both groups will have a baseline myocardial PET perfusion study to quantify the blood flow to the heart muscle, an electrocardiogram, an exercise treadmill stress test to assess exercise tolerance (fitness), a thorough review of the quality of their diet and a complete blood work covering individual lipid profiles. These tests and assessments will be repeated at 2 years and at 5 years.
In addition, subjects assigned to the standard medical management arm will be managed by current standard care provided by their primary referring physician and will be asked to come for clinic study visits annually for 5 years to document their medical and lifestyle management. The PET scan results will be blinded until the end of the study to the standard of care management group.
Subjects enrolled in the comprehensive medical management arm will have the support of a team of professionals focusing on atherosclerotic risk factor modification that involves recommended treatment to target lipid levels, blood pressure and diabetes control, smoking cessation, very low fat diet and aerobic exercise program. This is in addition to standard current medical therapy as provided by the primary referring physician.
No experimental medication or procedures will be used. Clinic visits for subject's education and consulting in the comprehensive program will be performed five times during the first year and semiannually thereafter.
At the end of the first 5 years, patients in the "comprehensive" medical management arm will be offered an additional 5-year follow-up at the current study location once a year.
The extended follow-up on cardiovascular or other adverse events for the "current standard of care" group will be based on yearly telephone or mail follow-up.
Both groups will have a full consultation visit, exercise treadmill and dipyridamole PET scan at the end of the total 10 years follow-up, replicating the current initial 5-year follow-up visit protocol.
