The study of myocardial perfusion and coronary anatomy imaging roles in CAD (SPARC): design, rationale, and baseline patient characteristics of a prospective, multicenter observational registry comparing PET, SPECT, and CTA for resource utilization and clinical outcomes

Objectives To design a multicenter study comparing the prognostic value and post-test resource utilization of PET, CT Coronary Angiography (CTA), and SPECT in clinical practice. Background Although PET, CTA, and SPECT are widely used, their relative clinical- and cost-effectiveness are undefined. Methods The Study of Myocardial Perfusion and Coronary Anatomy Imaging Roles in CAD (SPARC) is a prospective, multicenter, observational registry that has enrolled 3019 patients undergoing clinically referred SPECT, PET, and CTA with the goal of comparing post-test resource utilization and comparative prognostic value. Resource utilization assessment will enroll intermediate-high likelihood patients without prior CAD, while prognostic assessment will include both these patients and patients with prior CAD. Secondary analyses include assessments of diagnostic accuracy, cost, and referral to revascularization. Sites recruited into at least two of the three imaging arms. Except for semi-quantitative interpretation, site protocols will be used for all imaging studies and images forwarded to an image repository. Follow-up for catheterization, revascularization, cardiac death, myocardial infarction, all-cause death and medication use changes will be performed at 90-day, 1, and 2 years. Standard statistical methods will be used to risk-adjust results within and between study arms. SPARC will have >85% power (two-sided test, α = 0.01) to detect a 5% catheterization rate difference at 90 days between the three arms and >90% power to detect a 2% difference in cardiac death, or nonfatal MI within 2 years of the index test. Conclusions SPARC will be the first study comparing outcomes and resource utilization between SPECT, PET, and CTA in daily practice. In addition, the study design offers insights into inter-site and geographic differences in referral patterns and resource utilization.