Abstract 17126: Comparison of Wave-free Ratio with Fractional Flow Reserve in Patients with Diabetes Mellitus and with Prior Myocardial Infarction
Background: The instantaneous wave-free ratio (iFR) is adenosine-independent pressure-derived index, reported as a new method to evaluate coronary stenosis severity. Although previous studies reported the cut-off value of iFR was 0.86- 0.93, it is unclear whether or not it is applicable for the patients with diabetes mellitus (DM) and/or those with prior myocardial infraction (MI) in whom possible microvascular damage may exist.
Purpose: To evaluate of usefulness of iFR, and determine optimal cut-off value of iFR in patients with DM and prior MI.
Method: A total of 60 patients (80 stenosis) were assessed from November 2012 to December 2013. Of these, 25 patients (33stenosis; 41.2%) had DM and 23 (24 stenosis; 31.2%) had prior MI. Intracoronary pressure and flow velocity were measured distal to the stenosis at rest and during adenosine-mediated hyperemia. iFR was calculated and averaged using three heart beats,as a ratio of distal to proximal coronary pressures over the wave-free period in diastole.
Results: Vessel distribution was as follows, LAD (58%), LCX (19%) and RCA (23%). There was a strong correlation between iFR and fractional flow reserve (FFR) in all patients (r=0.76;P<0.001). Similar trends were observed in those with DM (r=0.77; P<0.001)and prior MI (r=0.83; P<0.001). Using the established FFR cut off threshold of 0.8 to define a positive result, area under the curve (AUC) of iFR in Receiver-operating characteristic curve analysis showed 0.87 (all patients), 0.96 (DM patients) and 0.90 (prior MI patients). The optimal cut-off value for iFR was 0.89 with a sensitivity of 78.1% (DM 92.3%, prior MI 78.6%) and a specificity of 91.7% (DM 82.5%, prior MI 100%).
Conclusion: iFR is a reliable index to assess the coronary stenosis in patients with DM and/or prior MI. The cut-off value of 0.89 in iFR is equivalent of 0.8 in FFR.
Author Disclosures: T. Ikeda: None. M. Ueno: None. S. Ikuta: None. T. Nakamura: None. K. Kobuke: None. Y. Iwanaga: None. S. Miyazaki: None.
- © 2014 by American Heart Association, Inc.