Background
The agreement between single-projection Murray-based quantitative flow ratio (
μ
QFR) and conventional three-dimensional quantitative flow ratio (3D-QFR) has not been reported hitherto.
Methods
Patients from a multinational database were randomly selected for the study of agreement, according to sample size calculation. Both conventional 3D-QFR and
μ
QFR were analyzed for all available arteries at a central corelab by independent analysts, blinded to each other’s results.
Results
Ninety-eight coronary arteries from 35 patients were finally analyzed. Median 3D-QFR was 0.82 (interquartile range 0.78–0.87). The intraclass correlation coefficient for the absolute agreement between 3D-QFR and
μ
QFR was 0.996 (95% confidence interval [CI]: 0.993–0.997); Lin’s coefficient 0.996 (95% CI: 0.993–0.997), without constant or proportional bias (intercept = 0 and slope = 1 in orthogonal regression). As dichotomous variable, there was absolute agreement between
μ
QFR and 3D-QFR, resulting in no single false positive or negative. Kappa index was 1 and the diagnostic accuracy 100%.
Conclusions
μ
QFR using a single angiographic projection showed almost perfect agreement with standard 3D-QFR. These results encourage the interchangeable use of
μ
QFR and 3D-QFR, which can be interesting to improve QFR feasibility in retrospective studies, wherein appropriate double angiographic projections might be challenging to obtain.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.