ABSTRACT
BACKGROUND: Measurement of fractional flow reserve (FFR) is the gold standard for determining the physiologic significance of coronary artery stenosis, but newer software programs can calculate the FFR from 2-dimensional angiography images. METHODS: A retrospective analysis was conducted using the records of patients with intermediate coronary stenoses who had undergone adenosine FFR (aFFR). To calculate the computed FFR, a software program used simulated coronary blood flow using computational geometry constructed using at least 2 patient-specific angiographic images. Two cardiologists reviewed the angiograms and determined the computational FFR independently. Intraobserver variability was measured using κ analysis and the intraclass correlation coefficient. The correlation coefficient and Bland-Altman plots were used to assess the agreement between the calculated FFR and the aFFR. RESULTS: A total of 146 patients were included, with 95 men and 51 women, with a mean (SD) age of 61.1 (9.5) y. The mean (SD) aFFR was 0.847 (0.072), and 41 patients (27.0%) had an aFFR of 0.80 or less. There was a strong intraobserver correlation between the computational FFRs (r = 0.808; P < .001; κ = 0.806; P < .001). There was also a strong correlation between aFFR and computational FFR (r = 0.820; P < .001) and good agreement on the Bland-Altman plot. The computational FFR had a high sensitivity (95.1%) and specificity (90.1%) for detecting an aFFR of 0.80 or less. CONCLUSION: A novel software program provides a feasible method of calculating FFR from coronary angiography images without resorting to pharmacologically induced hyperemia.
Subject(s)
Coronary Stenosis , Fractional Flow Reserve, Myocardial , Male , Humans , Female , Coronary Angiography/methods , Fractional Flow Reserve, Myocardial/physiology , Retrospective Studies , Coronary Stenosis/diagnostic imaging , Hemodynamics , Predictive Value of Tests , Coronary Vessels/diagnostic imaging , Severity of Illness IndexABSTRACT
BACKGROUND: Fractional flow reserve (FFR) is a gold standard to assess the impact of stenosis on the blood flow. The FFR method enhances diagnostic accuracy, lessens the need for stenting, and reduces costs. However, FFR is used in less than 10% of percutaneous coronary intervention (PCI) procedures because it needs pressure wires to measure the distal and proximal pressures and adenosine to create hyperemic conditions. Pressure-wire-based FFR measurement is, therefore, expensive and invasive. OBJECTIVE: This study aims to introduce a new approach on the basis of 3D coronary angiography and the Thrombolysis in Myocardial Infarction (TIMI) frame count for fast computation of FFR in patients with coronary artery disease. MATERIAL AND METHODS: In this simulation study, we herein introduce Non-Invasive Flow Ratio drawing upon CFD to measure FFR based on coronary angiography images with less run time. In this study, 3D geometry was created based on coronary angiography images. The mean volumetric flow rate was calculated using the TIMI frame count. FFR calculated based on CFD was compared with pressure-wire-based FFR and NiFR was calculated in 85 patients. RESULTS: The NiFR (r = 0.738, P< 0.001) exhibited a strong correlation with pressure-wire-based FFR. The result indicated that FFR was higher than 0.8 in the arteries with non-signif-icant stenosis and lower than 0.8 in the arter-ies with significant stenosis. CONCLUSION: The computational simulation of FFR and hemodynamic parameters such as pressure drop is a safe, efficient, and cost-effective method to evaluate the severity of coronary stenosis.
