Image-based FFR_Angio During Coronary Catheterization

Background: Fractional flow reserve (FFR) is a lesion-specific, physiological index determining the hemodynamic severity of coronary lesions.

Method: We have developed an image-based FFR technology based solely on already-available angiographic images. The algorithms estimate the functional significance of a coronary lesion by classifying the dynamic characteristics of the vessel as well as the patient’s hemodynamic information. An FFR measurement is provided for each segment of the coronary tree (Figure).

A validation study was performed in order to assess the diagnostic performance of the image-based FFR in comparison to invasive-FFR. Each lesion, indicated for invasive FFR measurement, was analyzed with the image-based technique, taking several views into consideration. The three dimensional shape of the vessels was used to initiate the flow analysis, and the FFR index at the exact location of the wire tip was compared to the pressure-based measurement.

Results: Invasive FFR index was measured during diagnostic cardiac catheterization and image-based FFR was calculated at the exact location of the invasive measurement. 122 lesions were analyzed and the image-based FFR demonstrated good correlation (r=0.85) to the conventional invasive method. The Bland-Altman analysis indicates that the 95% limits of agreement between the two methods ranged from -9% to 7%.

Conclusions: Calculation of FFR values from the coronary angiogram only, without the need of a pressure guide wire nor of any hyperemic stimulus, could have immense advantages in daily clinical practice. Our image-based FFR technology can detect the coronary physiology for `real time` diagnostic. This technology may reduce time and cost of the coronary diagnosis, enabling a comprehensive decision support system for the physician.