Paradoxical changes of coronary computed tomography derived fractional flow reserve

Area of Science:

• Cardiovascular Imaging
• Interventional Cardiology
• Computational Fluid Dynamics

Background:

• Computed tomography derived fractional flow reserve (FFR_CT) is a non-invasive tool for diagnosing coronary artery disease.
• Understanding factors influencing FFR_CT values is crucial for accurate stenosis assessment.
• Large ramus arteries (RAM) represent a specific coronary anatomy that may influence hemodynamic measurements.

Observation:

• A study of 1335 outpatients with suspected coronary artery disease analyzed FFR_CT.
• Only four patients exhibited a reverse increase of FFR_CT from proximal to distal segments.
• All patients with reverse FFR_CT increase had a large ramus artery (RAM).

Findings:

• The bifurcation angle was significantly higher in patients with reverse FFR_CT increase and RAM (106.0 ± 15.8°) compared to those with normal FFR_CT and RAM (82.6 ± 21.7°) or normal FFR_CT without RAM (66.9 ± 21.1°).
• Vessel length, lumen volume, plaque volume, and left ventricular mass were not significantly different between groups.
• A wider bifurcation angle in RAM may be associated with atypical FFR_CT patterns.

Implications:

• This suggests that anatomical variations, specifically the bifurcation angle in RAM, can influence FFR_CT interpretation.
• Clinicians should consider the impact of RAM anatomy on FFR_CT results to avoid misdiagnosis.
• Further research is warranted to validate these findings and explore the underlying mechanisms.