PRESENT AND FUTURE OF NUCLEAR CARDIOLOGY AND CARDIAC CT IN CAD: VALUE-BASED IMAGING
Daniel S. Berman, M.D., Cedars Sinai Medical Center, Los Angeles, CA, USA
The future use SPECT or PET, and cardiac CT will be based on their providing value by improving quality (e.g., reducing events) or decreasing costs. For prevention, coronary calcium scanning can provide value, guiding management more effectively than risk factors or other biomarkers. In patients with suspected CAD, CCTA is emerging as a potential first test of choice, based on its high sensitivity and specificity and strong prognostic value. In patients with acute chest pain, four randomized clinical trials have demonstrated that CCTA reduces time to diagnosis and safely increases rates of discharge from the emergency department, while saving or not increasing cost. In patients with known CAD or with extensive coronary calcification, CCTA is less useful, and SPECT myocardial perfusion imaging (MPI) has been shown to reduce admissions and costs. In the patient with stable symptoms and a low-intermediate likelihood of CAD, CCTA is playing an increasing role as the first diagnostic test. A normal CCTA examination has a “warranty” of at least 7 years, with almost no cardiac deaths over this period. While management of the patient with normal, non-obstructive or critically obstructed proximal vessels is clear, management of patients with lower-risk stenosis is not. In patients with a low-intermediate likelihood of CAD, CCTA likely will reduce costs with little effect on outcomes. In patients with a high likelihood of CAD, anatomic assessment by CCTA may be associated with increased costs and little effect on outcomes, thus not providing value. SPECT and PET MPI are most likely to have value in patients with a high likelihood of CAD, by decreasing revascularization in patients with no/minimal ischemia; however, in patients with low-intermediate/intermediate likelihood of CAD, MPI tests will likely increase costs and not affect outcomes. With both modalities, combined anatomic/physiologic assessment will expand their value and decrease layered testing.