| Objective1.Based on the results of coronary angiography,to investigate the distribution and clinical characteristics of myocardial bridges(MB)among pilots,and explore the relationship between myocardial bridges and clinical characteristics and its significance in aviation health and safety.2.To explore the application value of fractional flow reserve based on artificial intelligence deep learning(CT-FFR)in evaluating coronary hemodynamic changes of isolated myocardial bridge.Method1.Pilots underwent coronary artery angiography were retrospectively included from January 2010 to January 2020,and screened out pilots diagnosed with MB.Collect the general baseline data,flight data,clinical examination results and other indicators of the study subjects.Pilots were divided into 2 groups(MB group and non-MB group)according to the presence or absence of myocardial bridge in the left anterior descending coronary artery,compared the incidence of coronary atherosclerosis between the two groups,and used logistic regression model to analyze the risk factors of atherosclerosis.According to the conclusions of aeromedical evaluation,the pilots with MB were divided into flight qualified group and temporary flight unqualified group,and compared the difference of the clinical characteristics between the two groups.2.A collection of 41 patients with CCTA-confirmed isolated MB of the middle anterior descending coronary artery were retrospectively included in this study.According to the rate of the systolic stenosis rate of mural coronary artery(MCA),they were divided into2 groups,group A:stenosis rata≥50%,a total of 16 cases;group A:stenosis rata<50%,a total of 16 cases.The anatomical parameters of MB were measured.CT-FFR values were measured at three points(a:the proximal MCA,b:the MCA,c:the distal MCA)by DEEPVESSEL FFR software,and any MCA CT-FFR value≤0.80 is outliers.the differences in the anatomical parameters of MB and CT-FFR values were compared between the two groups.Result1.A total of 84 segments of myocardial bridge disease were detected in 79 pilots with MB.all located in the left coronary artery system,of which 62 cases occurred in the middle left anterior descending artery,accounting for 73.81%.2.Among the 79 patients with MB,30 had clinical manifestations of myocardial ischemia to varying degrees(1 had a myocardial infarction).The examination results showed that35 cases had positive treadmill exercise and 34 cases had abnormal ST-T ECG.3.The initial detection age of myocardial bridges of pilots was concentrated between 38-43 years old,and the detection age of combat crews were detected earlier than non-combat crews.4.28 cases of pilots with atherosclerotic lesions in MB group,including 26 cases of proximal myocardial bridge,2 cases of mural coronary artery segment,and 44 cases of pilots with atherosclerotic lesions in non-MB group,there is a statistical significance between the 2 groups(p=0.031);MB(OR=3.25,95%CI:1.56-6.81,P=0.002)and age of detection(OR=1.16,95%CI:1.09-1.22,P<0.001)are the risk factors that cause atherosclerosis.5.Of 79 pilots with MB,49 cases were qualified for flight,27 cases were temporarily unqualified,and 3 cases were unqualified.There were significant statistical difference in treadmill exercise results and myocardial ischemia symptoms between the qualified and temporarily unqualified groups(P<0.05).6.The median diameter area of the diastolic MCA segment in patients is 5.20mm~2,and the reference diameter area is(7.09±2.62)mm~2,there is a statistical difference between the two(P=0.003);The median diameter area of the systolic MCA segment is 2.80mm~2,and the reference pipe diameter area is(6.66±2.45)mm~2,there is a significant statistical difference between the two(P=0.000).The diastolic CT-FFR values of patients with MB at positions a,b,and c were 0.94(0.94,0.95),0.90(0.89,0.91)and 0.85(0.83,0.86),respectively;CT-FFR values at the 3 positions during systole were 0.95(0,94,0.95),0.89(0.87,0.90)and 0.84(0.81,0.86);The difference in CT-FFR values at different positions in both diastolic phase and systolic phase was statistically significant(P<0.001).7.The CT-FFR values decreased from diastolic phase to systolic phase in group A as well as group B(P>0.05).In diastolic phase,there was no significant difference in CT-FFR values at the three positions in group A and group B(P>0.05);A significant CT-FFR difference in position c was only found during systole between group A and group B(P=0.036),and there was no CT-FFR difference in position a and b.Conclusion1.Myocardial bridge is a common cause of abnormal treadmill movement of pilots.It usually occurs in the middle left anterior descending artery.2.Patients with myocardial bridge are prone to complicated with proximal atherosclerotic lesions,and may be secondary to myocardial ischemia symptoms,or even myocardial infarction,which requires the attention of aviation workers.3.MB can cause abnormal CT-FFR value in the distal MCA.4.The FFR based on artificial intelligence deep learning technology can be used to evaluate the changes in coronary hemodynamics of the myocardial bridge,and CT-FFR value can be used as an important basis for flight adaptability evaluation. |
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