Introduction:
Quantitative flow ratio (QFR) is a diagnostic modality for functional assessment for intermediate coronary stenosis without the use of pressure wire. QFR is calculated from 3-dimensional quantitative CAG (3D-QCA) using an advanced algorithm that enables fast computation of the pressure drop caused by coronary stenosis.
Hypothesis:
We assessed the usefulness of QFR and the association with an estimated coronary flow velocity (eCFV) for intermediate coronary stenosis.
Methods:
A total of 100 lesions in 80 consecutive patients were assessed Fractional Flow Reserve (FFR) for intermediate coronary stenosis between January 2011 and April 2019. Of these, 97 lesions in 77 patients who underwent QFR were included in this study. Patients were classified into two groups (FFR ≤ 0.80 or FFR > 0.80). QFR and eCFV using contrast were measured by Thrombolysis in Myocardial Infarction (TIMI) frame counts.
Results:
There was no significant differences in target vessels (p = 0.90) and diffuse lesions (p = 0.06) between the two groups (FFR ≤ 0.80 or FFR > 0.80). Mean FFR and QFR values were 0.78 ± 0.12 and 0.77 ± 0.11, respectively. QFR had a good correlation with FFR values (r = 0.86, p < 0.0001). The diagnostic accuracy, sensitivity, and specificity on QFR ≤ 0.80 were 91.8%, 92.7% and 90.5%, respectively. The eCFV of FFR ≤ 0.80 was greater than that of FFR > 0.80 (0.19 ± 0.08 m/s vs. 0.14 ± 0.06 m/s, p<0.001). Figure showed that the eCFV correlated with FFR values (r = -0.29, p < 0.01). Moreover, the eCFV had a high area under the curve (AUC = 0.71, p < 0.01) on Receiver operating characteristics curve (ROC) analysis with FFR ≤ 0.80.
Conclusions:
QFR was useful for the assessment of functional stenosis severity. As eCFV was faster, FFR was lower for intermediate coronary stenosis. The eCFV had a good correlation with FFR and may become one of the evaluations for ischemia.
Effect of one or more co-morbid conditions on diagnostic accuracy of coronary flow velocity reserve for detecting significant left anterior descending coronary stenosis