[Comparison of Diagnostic Values of Instantaneous Wave-Free R atio and Fractional Flow R eserve With Noninvasive Methods for Evaluating Myocardial Ischemia in Assessment of the Functional Significance of Intermediate Coronary Stenoses in Patients With Chronic Ischemic Heart Disease].

OBJECTIVE: To compare the diagnostic accuracy of instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) with noninvasive methods in assessment of the functional significance of moderate coronary stenoses in patients with chronic ischemic heart disease (IHD).

METHODS: We included in this study 50 patients with chronic or suspected IHD and moderate coronary stenoses (50-70%; 74 stenoses). Values of iFR and FFR were determined within 10 days after noninvasive stress tests (combination of stress-echo and SPECT). The values of iFR and FFR were compared with the results of noninvasive methods by ROC-analysis. Coronary artery stenosis was considered functionally important if at least one of noninvasive tests (stress-echo or SPECT) demonstrated positive result.

RESULTS: The results of noninvasive stress-tests were positive in 14 patients (28%). ROC area under the curve (AUC) for iFR - 0.961±0.019 (95%CI 0.888-0.992). The best cut-off point for iFR is 0.92 (sensitivity 100, specificity 84%). ROC AUC for FFR - 0.893±0.041 (95%CI 0.79-0.96). The best cut-off point for FFR is 0.81 (sensitivity 100% and specificity 69%). There was no significant difference between iFR and FFR ROC-curves (р=0.0845).

CONCLUSION: The values of iFR and FFR have equivalent agreement with the results of noninvasive tests commonly used to detect myocardial ischemia in patients with moderate coronary stenoses.