For coronary artery diseases, imaging diagnosis is usually used to guide the treatment. However, it can only reflect the geometric characteristics of the disease but does not determine the hemodynamically significant stenosis. This study was aimed to investigate the relationship between angiographic and functional severity of coronary artery stenosis and to improve the diagnostic value of imaging. 39 patients with 55 stenosis vessels were included in this study. The correlation between FFR and stenosis rate was analyzed with the medical statistical analysis method, and the influence of the position of stenosis and coronary dominant type on the correlation was discussed. By regression analysis, the stenosis rate of left anterior descending artery of right dominant type showed a significant correlation with FFR value (r≈0.79, P < 0.000 1) after grouping with position and the dominant type. Due to the significance of a value of the FFR < 0.80 in determining inducible ischemia, the diagnostic accuracy of myocardial ischemia by the stenosis rate increased from 70.9% to 82.8% after grouping. Sensitivity (from 72.2% to 78.6%) and specificity (from 70.3% to 86.7%) were also significantly improved. This study indicates that the position of stenosis and the coronary dominant type are significant influence factors on the correlation between FFR and stenosis rate. Consideration of these two factors in the diagnosis of myocardial ischemia by imaging will be helpful to improve the effectiveness of diagnosis.
In order to investigate the application of lattice Boltzmann method (LBM) in the numerical simulation of computed tomography angiography-derived fractional flow reserve (FFRCT), an idealized narrowed tube model and two coronary stenosis arterymodels are studied. Based on the open source code library (Palabos), the relative algorithm program in the development environment (Codeblocks) was improved. Through comparing and analyzing the results of FFRCT which is simulated by LBM and finite element analysis software ANSYS, and the feasibility of the numerical simulation of FFRCT by LBM was verified . The results show that the relative error between the results of LBM and finite element analysis software ANSYS is about 1%, which vertifies the feasibility of simulating the coronary FFRCT by LBM. The simulation of this study provides technical support for developing future FFRCT application software, and lays the foundation for the calculation of clinical FFRCT.
New functional evaluation methods for coronary artery lesions have received widespread attention at home and abroad. As a new functional evaluation technique, the clinical value of quantitative flow ratio (QFR) in the accuracy and feasibility of diagnosing myocardial ischemia caused by coronary artery stenosis has been confirmed in many clinical trials. Compared with the traditional gold standard fractional flow reserve (FFR) for diagnosing coronary artery stenosis, QFR has the advantages of simple operation, time-saving and low cost. This article reviews the comparison of the diagnostic accuracy of FFR and QFR and the progress of clinical research, aiming to explore whether QFR may replace FFR as a functional evaluation method of coronary artery disease and guide clinical blood circulation reconstruction.
Coronary artery fractional flow reserve (FFR) is a critical physiological indicator for assessment of impaired blood flow caused by coronary artery stenosis. The wire-based invasive measurement of blood flow pressure gradient across stenosis is the gold standard for clinical measurement of FFR. However, it has the risk of vascular injury and requires the use of vasodilators, increasing the time and overall cost of interventional examination. Coronary imaging is playing an important role in clinical diagnosis of stenotic lesions, evaluation of severity of lesions, and planning of therapies. In recent years, the computation of FFR based on the physiological information of blood flow obtained from routinely collected coronary image data has become a research focus in this field. This technique reduces the cost of physiological assessment of coronary lesions and the use of pressure wires. It is beneficial to strengthen the physiological guidance in interventional therapy. In order to better understand this emerging technique, this paper highlights its implementation principle and diagnostic performance, analyzes practical problems and current challenges in clinical applications, and discusses possible future development.
We reported a 59-year-old male with exertional angina pectoris, and the coronary angiography showed multiple vessel lesions. The initial strategy was coronary artery bypass grafting (CABG). The measurement of quantitative flow ration (QFR) before operation indicated that the posterior descending branch (PD) did not need to be treated. The left circumflex branch (LCX) was small, and the QFR of the left anterior descending branch (LAD) and the first diagonal branch (D1) was<0.8. Therefore, the LAD and D1 were re-vascularized. The operation strategy was changed to on-pump CABG through a small incision, and the final strategy was LIMA-D1-LAD (sequential), fractional flow reserve (FFR) of distal LAD and D1 after CABG were>0.8 by computed tomography FFR. SYNTAX scores after CABG were 20 and the functional SYNTAX scores after CABG were 3, indicating a good prognosis.