Objective: To explore the application value of quantitative flow ratio (QFR) in the hemodynamic evaluation of myocardial bridge and to preliminarily evaluate the correlation and related influencing factors between deformation quantitative flow ratio (D-QFR) and QFR. Methods: This is a cross-sectional study. Patients with CAG-confirmed simple myocardial bridge of the middle anterior descending coronary artery from June 2012 to June 2022 at the Air Force Medical Center were retrospectively included in this study. Systolic stenosis of mural coronary arteries (MCA) and myocardial bridge length were measured using quantitative coronary angiography. The patients were divided into mild stenosis group (<50% systolic stenosis) and moderate-to-severe stenosis group (≥50% systolic stenosis) according to the Nobel grading criteria. At different time periods (systolic and diastolic), the QFR values were measured at 3 locations (1 to 2 cm before the MCA entrance, the middle segment of the MCA, and 1 to 2 cm after the MCA exit), denoted as QFRa, QFRb, and QFRc, respectively, and the D-QFR values, incorporating vessel deformation information, were recorded. The MCA distal QFR≤0.8 in either stage was defined as an abnormal QFR value. QFR values were compared between the two groups at different locations and within each group. Factors associated with abnormal QFR values were analysed using multifactorial logistic regression. Spearman rank correlation analysis was used to examine the correlation between D-QFR values and systolic and diastolic QFR values.Multiple linear regression was used to analyse the factors associated with D-QFR. Results: A total of 83 patients were enrolled, including 58 males, aged (57.1±13.1) years. There were 48 cases in the mild stenosis group and 35 cases in the moderate-to-severe stenosis group, and the differences in systolic and diastolic QFRb and QFRc values between the two groups were statistically significant (all P<0.05). Within-group comparisons showed the values of QFRb and QFRc in the systolic phase were lower than those in the diastolic phase; QFRb and QFRc were both lower than QFRa during the same period (all P<0.05). Multifactorial logistic regression analysis showed that MCA systolic stenosis (OR=1.225, 95%CI 1.093-1.372, P<0.001) was an influential factor for abnormal QFR. D-QFR values were positively correlated with both systolic and diastolic QFR values (correlation coefficients were 0.849 and 0.675, respectively, both P<0.01). Multiple linear regression analysis showed that D-QFR values were negatively correlated with age (β=-0.208, P=0.029), systolic stenosis (β=-0.500, P<0.001), and myocardial bridge length (β=-0.211, P=0.036). Conclusions: The QFR values in middle and distal of myocardial bridge decrease. The systolic stenosis rate of myocardial bridge is an important factor affecting QFR value. D-QFR is positively correlated with both systolic and diastolic QFR values. Age, myocardial bridge systolic stenosis rate and length are factors influencing the D-QFR values.
目的： 探讨新一代定量血流分数（QFR）在心肌桥血流动力学评估中的应用价值以及初步探索形变定量血流分数（D-QFR）与QFR的相关性及相关因素。 方法： 本研究为横断面研究。入选2012年6月至2022年6月于空军特色医学中心行冠状动脉造影检查提示单纯性心肌桥患者。采用定量冠状动脉造影测量心肌桥收缩期狭窄率及心肌桥长度。根据Nobel分级标准，将患者分为轻度狭窄组（收缩期狭窄率<50%）和中重度狭窄组（收缩期狭窄率≥50%），测量不同时相（包括收缩期和舒张期）3个位置（MCA入口前1~2 cm、MCA中间段、MCA出口后1~2 cm）的QFR数值，分别记作QFRa、QFRb、QFRc，并且记录加入血管形变信息分析的D-QFR值。将任一时相壁冠状动脉远端QFR≤0.8定义为QFR值异常。比较两组不同位置以及各组内不同位置、不同时相QFR值。采用多因素logistic回归分析QFR值异常的相关因素。采用Spearman秩相关分析D-QFR值与收缩期及舒张期QFR值的相关性。采用多元线性回归分析D-QFR的相关因素。 结果： 共入选83例患者，其中男性58例，年龄（57.1±13.1）岁。轻度狭窄组48例，中重度狭窄组35例，两组收缩期及舒张期QFRb、QFRc值差异均有统计学意义（P均<0.05）。组内比较结果显示，QFRb、QFRc在收缩期的测值均低于舒张期；QFRb及QFRc均低于同期的QFRa（P均<0.05）。多因素logistic回归分析结果显示，心肌桥收缩期狭窄率（OR=1.225，95%CI 1.093~1.372，P<0.001）为QFR异常的相关因素。D-QFR值与收缩期及舒张期QFR值均呈正相关（相关系数分别为0.849、0.675，P均<0.001）。多元线性回归分析结果显示D-QFR值与年龄（β=-0.208，P=0.029）、收缩期狭窄率（β=-0.500，P<0.001）及心肌桥长度（β=-0.211，P=0.036）均呈负相关。 结论： 心肌桥中远端的QFR值下降；心肌桥收缩期狭窄率为QFR值异常的重要相关因素。D-QFR与收缩期及舒张期QFR值均呈正相关；患者的年龄、收缩期狭窄率及心肌桥长度均是D-QFR值的相关因素。.