Quantification of effects of mean blood pressure and left ventricular mass on noninvasive fast fractional flow reserve.

Proper inlet boundary conditions are essential for accurate computational fluid dynamics (CFD) modeling. We developed methodology to derive noninvasive FFR_B using CFD and computed tomography coronary angiography (CTCA) images. This study aims to assess the influence of brachial mean blood pressure (MBP) and total coronary inflow on FFR_B computation. Twenty-two patients underwent both CTCA and FFR measurements. Total coronary flow was computed from left ventricular mass (LVM) measured from CTCA. A total of 286 CFD simulations were run by varying MBP and LVM at 70, 80, 90, 100, 110, 120, and 130% of the measured values. FFR_B increased with incrementally higher input values of MBP: 0.78 ± 0.12, 0.80 ± 0.11, 0.82 ± 0.10, 0.84 ± 0.09, 0.85 ± 0.08, 0.86 ± 0.08, and 0.87 ± 0.07, respectively. Conversely, FFR_B decreased with incrementally higher inputs value of LVM: 0.86 ± 0.08, 0.85 ± 0.08, 0.84 ± 0.09, 0.84 ± 0.09, 0.83 ± 0.10, 0.83 ± 0.10, and 0.82 ± 0.10, respectively. Noninvasive FFR_B calculated using measured MBP and LVM on a total of 30 vessels was 0.84 ± 0.09 and correlated well with invasive FFR (0.83 ± 0.09) (r = 0.92, P < 0.001). Positive association was observed between FFR_B and MBP input values (mmHg) and negative association between FFR_B and LVM values (g). Respective slopes were 0.0016 and −0.005, respectively, suggesting potential application of FFR_B in a clinical setting. Inaccurate MBP and LVM inputs differing from patient-specific values could result in misclassification of borderline ischemic lesions. NEW & NOTEWORTHY While brachial mean blood pressure (MBP) and left ventricular mass (LVM) measured from CTCA are the two CFD simulation input parameters, their effects on noninvasive fractional flow reserve (FFR_B) have not been systematically investigated. We demonstrate that inaccurate MBP and LVM inputs differing from patient-specific values could result in misclassification of borderline ischemic lesions. This is important in the clinical application of noninvasive FFR in coronary artery disease diagnosis. [ABSTRACT FROM AUTHOR]