Coronary artery disease (CAD) remains one of the most common causes of morbidity and mortality. Diagnostic imaging accounts for much of the costs associated with the care of patients with CAD. Although non-invasive functional studies are the initial tests used to evaluate patients with suspected obstructive CAD, studies have shown that they are not always accurate. With the advent of PET/CT scanners, combined functional and anatomical imaging may improve risk stratification, which may lead to improved outcomes and reduced costs.
We will perform a retrospective, randomized blinded analysis to determine whether PET/CTA changes clinical decision making, leading to reduced costs. We will also compare the accuracy of PET/CTA in the diagnosis of obstructive CAD, using x ray angiography as the standard.
Overview: This is a single center study enrolling 64 consecutive patients who have been referred for invasive CA who have had a prior SPECT MPI within 2 months of recruitment. All patients will undergo PET/CTA imaging before scheduled invasive CA or any coronary intervention. For the analysis of diagnostic accuracy, the SPECT and PET/CTA results are compared to the invasive CA results. For the clinical decision-making analysis, the SPECT and PET/CTA studies are separated and randomized into two clinical scenarios: 1) patients with only the SPECT information available, and 2) patients with only the PET/CTA information available. Three cardiologists blinded to the original clinical decisions will determine the "theoretical" management of the patients and answer the following questions:
1) Would you refer the patient to medical management or invasive CA?
2) If referred to invasive CA, do you think that the patient will receive PCI?
3) If the patient receives PCI, in which major coronary artery will the intervention be performed?
After a waiting period of 4 weeks, the cardiologists will be asked to reassess the same questions on a re-randomized set of PET/CTA studies and a re-randomized set of SPECT studies (Blinded Analysis 2). For the cost analysis, current market costs associated with non-invasive and invasive testing will be calculated.
Setting: The study will be performed in the nuclear medicine laboratory at the VAPAHCS. The study site is chosen because the PET/CTA and archived SPECT MPI images are located in this department.
Chart Review and Laboratory Tests: The patient's electronic medical record will be reviewed to assess patients eligibility for the study.
Data Analysis: For data analysis, the study investigators, who will interpret the images and generate the imaging report, will be blinded to the clinical information.
Thirty-six male Caucasian veterans were consecutively recruited. Average age was 60.2 5.1, ranging from 53 to 70 years. All patients underwent PET/CTA procedures within 6 months of their incident SPECT and within 4 weeks of their angiogram. There were no complications. Three physicians trained in nuclear medicine and CT angiography will interpret the images, using computerized software. A report will be generated. Three cardiologists blinded to the original clinical decisions will determine the "theoretical management of patients after reviewing the randomized images. After a waiting period of 4 weeks, the cardiologists will be asked to repeat the management. For the cost analysis, current market costs associated with noninvasive testing will be calculated.
By examining how PET/CTA impact clinical management, we can determine if this will be a useful tool in this patient population. This could change the current standard of care of non invasive imaging of patients with coronary artery disease. This could impact the need for invasive imaging in a subset of patients with coronary artery diisease. We will determine this after the completion of recruitment and analysis of patients.
- Krishnan U, Parekh VI, Nguyen P, Bowling SA, Saint S, Goldberger ZD. A lifetime in the making. Journal of hospital medicine. 2011 May 1; 6(5):304-8.