Combined coronary CT angiography and myocardial perfusion imaging did not alter treatment strategy compared to MPI alone in intermediate and high risk patients

Objectives Stress myocardial perfusion imaging (MPI) is the most common imaging test for patients with suspected or known coronary artery disease (CAD). Several studies have described that combined CCTA, a recently developed method, and MPI has excellent accuracy before revascularization. However, high radiation exposure and cost are major drawbacks, and whether the addition of CCTA to MPI provides incremental information in managing patients with intermediate to high CAD risk remains unclear.

Methods Between August 2009 and September 2010, in 29 patients (age 64.3±11.4 years, 25 males) referred for elective coronary angiography (CAG), combination of CCTA and MPI using 201Tl SPECT were performed. Twelve patients (41.4%) had history of revascularization. The rest of patients included 3 (10.3%) classified as intermediate and 14 (48.3%) as high risk by Framingham risk score. The interval between the first non-invasive test and CAG was 3.3±2.4 months. All patients were followed at least one year after the index imaging test.

Results CAG demonstrated significant CAD (luminal stenosis ≥50%) in 23 patients and 41 vessels. Detecting significant CAD by MPI alone or combined CCTA and MPI in vessel-based analysis had similar diagnostic accuracy (67% vs. 69%, P=NS). Percutaneous coronary intervention (PCI) was performed in 17 patients and coronary artery bypass surgery in one. The remaining 5 patients included one with total occlusion with collaterals, two with PCI failure, and two with medical treatment.

Conclusions In clinical practice, no significant difference of treatment strategy with additional CCTA compared to MPI alone in patients with intermediate-high risk or proven CAD is observed, and MPI alone yields similar 1-year post-test outcome