Impact of Plaque Eccentricity on the Diagnostic Performance of Murray-Law Based Quantitative Flow Ratio Computed From...

Murray-law based quantitative flow ratio (μFR) enables rapid fractional flow reserve (FFR) computation from invasive coronary angiography (ICA) using a single projection, but the influence of plaque eccentricity on its diagnostic accuracy remains unclear.

To investigate whether eccentric plaque impacts the diagnostic accuracy of single-view μFR.

We performed a blinded analysis of the prospective CAREER trial database, enrolling patients with 30%-90% diameter stenosis on coronary computed tomography angiography (CCTA) who underwent μFR and FFR assessments within 30 days. ICA were acquired using standardized, protocol-specified projections. CCTA images were analyzed using dedicated software and co-registered with ICA. For each μFR-identified lesion, plaque eccentricity index (PEI) and lumen asymmetry index (LAI) were computed across all cross-sections and averaged to yield PEI and LAI per-vessel. Vessels were classified as having eccentric/concentric plaques using median PEI, and subclassified as having asymmetric/symmetric lumens using median LAI.

Among 231 vessels (201 patients), median μFR and FFR were 0.84 and 0.83, respectively. PEI and LAI moderately correlated (ρ = 0.46, p < 0.001). Limits of agreement between μFR and FFR were wider in eccentric versus concentric plaques (standard deviation 0.08 vs. 0.06; p = 0.003), mainly driven by presence of asymmetric lumens (standard deviation 0.09 vs. 0.06 in symmetric lumens; p = 0.029). μFR had comparable AUC for predicting FFR ≤ 0.80 between concentric plaques and eccentric plaques with symmetric lumens (0.94 vs. 0.95; p = 0.909).

The diagnostic accuracy of single-view μFR, derived from standardized angiographic projections, was moderately affected by eccentric plaques, with the effect primarily attributable to asymmetric lumens.