CT iFR/FFR Will Make Coronary Angiography Unnecessary

1.1  /  IAGS 2019
Session 1: Coronary Session 1 – Elective PCI
CT iFR/FFR Will Make Coronary Angiography Unnecessary
Problem Presenter: George S. Hanzel, MD

Statement of the problem or issue

More than 50% of patients undergoing invasive angiography are found to have non-obstructive coronary artery disease (CAD). Stress imaging modalities have sensitivity and specificity of 70%-80%, respectively. Although coronary CT angiography (CTA) has a high sensitivity, the specificity is quite low. Coronary CTA/FFR_CT provides both anatomical and physiological data and has been shown to be superior to SPECT and PET stress testing for assessment of ischemia. A modest-sized study has demonstrated an impressive 80% reduction in the need for invasive angiography compared with standard care. Importantly, this was coupled with an extremely low rate of major adverse cardiac events (MACE) in those in whom angiography was deferred. Thus, CTA/FFR_CT is poised to become the new “gate keeper” to the cath lab.

Gaps in knowledge

Despite its excellent diagnostic performance, the adoption of CTA/FFR_CT has been slow in the United States, as well as most of the rest of the world. Some issues are mundane, such as variable reimbursement policies, and control of CTA by radiology. However, it must be acknowledged that the current data regarding outcomes and the reduction in invasive angiography are based on a small number of modestly-sized trials of stable chest pain patients. Additionally, there is a paucity of data on acute chest pain patients. 

Possible solutions and future directions

Additional randomized trials, as well as real-world registries, are required to confirm early studies of stable chest pain patients to verify the reported substantial reduction in rates of invasive angiography by CTA/FFR_CT. These studies should also assess long-term MACE and the possible subsequent need for invasive angiography and PCI in patients in whom angiography was deferred. Studies also need to be performed in the important subgroup of acute chest pain patients, in whom it may also be important to move beyond just lesion-specific ischemia and incorporate plaque characterization as well as novel CTA indices to evaluate plaque vulnerability. The utility of these adjunctive indices will need to be studied. In those patients who do undergo invasive angiography, CTA/FFR_CT can be used for PCI planning. Whether PCI planning with “virtual stenting” actually adds value to the PCI procedure will need to be determined. Cost-effectiveness analyses need to be performed. From a practical standpoint, cardiologists will need to partner with radiologists to develop viable CTA/FFR_CT programs and work with insurance carriers to secure reimbursement in order to bring this technology into mainstream clinical care.