On the relationship between competitive flow and FFT analysis of the flow waves in the left internal mammary artery graft in the process of CABG

Abstract

BackgroundDuring coronary artery bypass grafting (CABG), the ratio of powers of the fundamental frequency and its first harmonic (F0/H1) in fast Fourier transformation (FFT) analysis of the graft’s flow waves has been used in the field of evaluation of the patency in anastomosis. But there is no report about using the FFT method to evaluate the magnitude of competitive flow. This study is aiming at exploring the relationship between competitive flow and FFT analysis of the flow waves in left internal mammary artery (LIMA) graft, and finding a new method to evaluate the magnitude of competitive flow.MethodsAt first, establishing the CABG multiscale models of different stenosis in left anterior descending artery (LAD) to get different magnitude of competitive flows. Then, calculating the models by ANSYS-CFX and getting the flow waves in LIMA. Finally, analyzing the flow waves by FFT method and comparing the FFT results with the magnitude of competitive flow.ResultsThere is no relationship between competitive flow and F0/H1. As for F0/H2 and F0/H3, they both increase with the reduction of the stenosis in LAD. But the increase of F0/H3 is not obviously enough and it can’t identify the significant competitive flow clearly, so it can’t be used as the evaluation index. It is found that F0/H2 increases obviously with the increase of the competitive flow and can identify the significant competitive flow.ConclusionThe FFT method can be used in the evaluation of competitive flow and the F0/H2 is the ideal index. High F0/H2 refers to the significant competitive flow. This method can be used during CABG to avoid the risk of competitive flow.

Transit time flow measurement in arterial grafts

“…A less commonly used TTFM parameter is the fast Fourier transform (FFT) ratio which is based on the analysis of the blood flow curve on TTFM. The major benefit of using FFT to predict patency is that it is relatively “resistant” to competitive flow compared to the other TTFM parameters, both in a multiscale modal [ 18 ] and in clinical data [ 19 ]. Of note, TTFM values are affected by blood pressure during the measurement – there is a direct correlation between blood pressure and flow.…”

Effects of Fractional Flow Reserve on Coronary Artery Bypass Graft Flow to Left Anterior Descending Artery

“…Harmonics exist at frequencies that are multiplies of the fundamental frequency and are described in terms of an amplitude and phase. 13,14 Postoperative Evaluation For postoperative graft evaluation, every patient underwent cardiac imaging with MSCTA approximately 2 months after CABG as a routine checkup, using a β-blocker and isosorbide mononitrate to ensure the adequacy of images. In addition, every patient routinely underwent adenosine stress and rest myocardial perfusion scintigraphy approximately 2 months after CABG, using adenosine infused at a rate of 0.14 mg/kg/min for 6 min and 111-148 MBq of Thallium-201 administered 3 min before the end of the adenosine infusion.…”

Preface: Computational and experimental methods for biological research: cardiovascular diseases and beyond

“…Effectiveness of stents and grafts were studied in [18, 22, 23]. Gu et al [21] studied the effect of captopril on the performance of the control strategies of BJUT-II VAD.…”