Comparison of 3-dimensional and 2-dimensional quantitative coronary angiography and intravascular ultrasound for functional assessment of coronary lesions

Background: Three-dimensional quantitative coronary angiography (3D-QCA) reportedly allows more accurate delineation of true vessel geometry when compared with standard two-dimensional (2D) QCA and has been validated by intravascular ultrasound (IVUS). This study sought to compare diagnostic efficiency of 2D- and 3D-QCA, and IVUS in identifying hemodynamically significant coronary stenoses as determined by fractional flow reserve (FFR).

Methods: Forty-two lesions in 40 patients were assessed by FFR, IVUS, and 2D- and 3D-QCA. Correlations between FFR values and anatomical parameters obtained by 2D- and 3D-QCA and IVUS were analyzed. The receiver operating characteristic (ROC) curves were used to compare the diagnostic accuracy of the parameters for predicting FFR≤0.80.

Results: Mean FFR value was 0.75±0.13. FFR≤0.80 was observed in 28 lesions (67%). Of IVUS measurements, minimum lumen area (MLA) well correlated with FFR values (r=0.71, p<0.001). Of 3D- and 2D-QCA measurements, minimum lumen diameter (MLD) correlated best with FFR values (r=0.79, p<0.01; r=0.68, p<0.01, respectively), followed by MLA (r=0.76, p<0.01; r=0.67, p<0.01, respectively). The area under the ROC curve for 3D-QCA MLD was greater than those for 2D-QCA MLD (p=0.03) and 2D-QCA MLA (p=0.03). On the other hand, the AUC for 3D-QCA MLD, 3D-QCA MLA, and IVUS MLA were not significantly different.

Conclusions: 3D-QCA is more useful than 2D-QCA and possibly comparable to IVUS in the assessment of functional stenosis severity. When FFR is not available, 3D-QCA MLA and MLD may assist in the assessment of functional severity of intermediate lesions.