Meta-Analysis Highlights Potential Utility of CCT-FFR in Stable CAD Management

The clinical implications of CCT-derived fractional flow reserve (FFRct) in managing stable coronary artery disease (CAD) continue to be a subject of ongoing discussion. To further elucidate the potential benefits of incorporating this non-invasive modality into our diagnostic armamentarium, a meta-analysis was conducted comparing outcomes in patients with suspected stable CAD undergoing FFRct as a first-line strategy versus conventional non-urgent cardiovascular testing guided by clinical assessment.

This analysis encompassed five studies (three randomized controlled trials and two observational studies), representing a total of 5,282 patients. The studies compared two distinct diagnostic and management strategies:

• CCT-FFR as a first strategy: In this approach, patients initially underwent Coronary Computed Tomography Angiography (CCTA). CCTA is a non-invasive imaging technique that uses X-rays and contrast dye to visualize the coronary arteries. If CCTA revealed the presence of coronary artery stenosis (narrowing), further analysis was often performed to calculate the fractional flow reserve derived from CCTA (FFRct). FFRct is a computational technique that uses CCTA images to estimate how much a stenosis limiting blood flow to the heart muscle. This functional information helps determine the physiological significance of the stenosis. Management decisions, such as whether to pursue invasive coronary angiography or revascularization (e.g., PCI or CABG), were then guided by the CCTA and, when performed, the FFRct results.

• Non-urgent cardiovascular testing after a clinical judgment (Control Group): This strategy involved a more traditional approach to evaluating patients with suspected stable CAD. Patients underwent a clinical assessment, including a review of their symptoms, risk factors, and medical history. Based on this assessment, physicians selected appropriate non-invasive or invasive diagnostic tests. These tests could include:

  • Exercise stress testing: To evaluate heart function during physical exertion.

  • Nuclear stress testing (SPECT): To assess blood flow to the heart muscle.

  • Stress echocardiography: To assess heart function and wall motion during stress.

  • Invasive coronary angiography (ICA): A procedure in which a catheter is inserted into the coronary arteries to visualize them with X-rays.

The choice and sequence of these tests were determined by the physician's clinical judgment, following established guidelines.

Of the total patients, 2604 underwent CCT-FFR as the initial strategy, while 2678 patients comprised the control group, receiving standard clinical assessment and subsequent non-invasive or invasive testing as deemed appropriate. Quantitative synthesis of the data revealed the following key findings:

• Reduced Invasive Coronary Angiography (ICA) Rates: The CCT-FFR strategy was associated with a significant reduction in the overall rate of ICA (OR 1.57, 95% CI 1.36–1.81, p < 0.001).

• Lower Rates of Non-Obstructive CAD on ICA: Notably, the likelihood of undergoing ICA and demonstrating no obstructive CAD was substantially lower in the CCT-FFR group (OR 6.63, 95% CI 4.79–9.16, p < 0.001).

• Increased Rates of Coronary Revascularization: Conversely, patients in the CCT-FFR arm underwent coronary revascularization more frequently compared to the control group (OR 0.48, 95% CI 0.38–0.62, p < 0.001).

• Comparable 1-Year Major Adverse Cardiac Events (MACE): Despite the differential rates of subsequent procedures, there was no statistically significant difference in the incidence of 1-year MACE between the two strategies (OR 1.11, 95% CI 0.86–1.44, p = 0.42). Similarly, rates of nonfatal myocardial infarction (OR 0.73, 95% CI 0.41–1.33, p = 0.31), all-cause mortality (OR 1.29, 95% CI 0.47–3.54, p = 0.63), and unplanned revascularization for angina (OR 0.99, 95% CI 0.65–1.49, p = 0.95) were comparable between the groups.

Conclusion:

This meta-analysis suggests that in the management of stable CAD, an initial strategy incorporating CCT-FFR is associated with lower overall rates of ICA and a reduced likelihood of ICA demonstrating non-obstructive disease. Furthermore, this approach appears to facilitate higher rates of coronary revascularization. However, it is important to note that these differences did not translate into a statistically significant difference in 1-year clinical outcomes, as assessed by MACE.

These findings warrant careful consideration as we strive to optimize diagnostic pathways for patients with stable CAD. While CCT-FFR demonstrates potential for reducing unnecessary invasive procedures and potentially guiding more targeted revascularization, further investigation into its long-term clinical impact and cost-effectiveness is warranted.

Key Take-Home Points:

• CCT-FFR as an initial strategy in stable CAD management is associated with fewer overall ICAs.

• The use of CCT-FFR leads to a lower likelihood of ICAs revealing no significant blockages.

• CCT-FFR appears to result in higher rates of coronary revascularization.

• Despite these differences in procedures, 1-year rates of MACE, MI, mortality, and unplanned revascularization were similar between the CCT-FFR and standard care groups.

• While CCT-FFR shows promise in refining diagnostic pathways and potentially guiding treatment, its long-term clinical impact requires further study.