| Objective To observe the characteristics of left anterior descending(LAD)myocardial bridge(MB)by intravascular ultrasound(IVUS).Methods Fifty patients diagnosed as LAD MB by coronary angiography(CAG)were further examined by IVUS.Location of MB,MB length,MB thickness,area of elastic membrane area(EEMA),lumen area(LA),plaque length,plaque thickness,plaque area(PA),maximum plaque burden(PB),and vascular remodeling index(RI)were measured and analyzed.Results 1.33 MB located at the middle of LAD,17 located at the distal segment of LAD.2.There was a positive correlation between the degree of compression and its stenosis in mural coronary artery(MCA)(r=0.273,p<0.05).There was no correlation between the degree of MCA compression and MB length(r=0.237,p>0.05)or MB thickness(r=0.117,p>0.05).There was no correlation between MB length and thickness(r=0.181,p>0.05).There was no correlation between the degree of MCA compression and anyone of age,LVEF,TG,TC,HDL-C,LDL-C,FBG,HGB,PLT and CREA(p>0.05).3.Male is the independent predict factor of Nobel Classification(p<0.05).4.The plaques located at every segment of LAD.Anyway,the most was detected at MB proximal segment in 50 cases,the number is higher than that of MCA segment(15cases)or MB distal segment(20 cases)(either p<0.05).There was no significance between the plaque numbers of MCA and MB segments(p>0.05).5.Positive vascular remodeling was detected only in the proximal of MB in 17 patients,the difference was significant between the numbers of the proximal and the MCAsegment(0 patient)or MB distal segment(0 patient)(either p<0.05).Negative remodeling was detected in all three segments of LAD,the most was found in the proximal in 22 cases,the number is much higher than that of MCA(10 cases)segment(p<0.05).6.Plaques were detected at MB proximal segment in all 50patients(44 eccentric plaques,6 central plaques).MCA plaques were found in 15patients(all eccentric plaque),and MB distal plaques were diagnosed in 20 cases(all eccentric plaques).The plaque number of the proximal was higher than that of the MCA or MB segment(either p<0.001).Neither eccentric plaque nor central plaque there was a difference during the three segments(p>0.05).7.The EEMA[(19.06±5.926mm~2)vs(6.30±1.995mm~2)],PA [(9.52±3.42mm~2)vs(4.92±2.177mm~2)],PB [(64.37±12.921%)vs(50.07±10.498%)],plaque length[(39.94±13.401mm)vs(8.08±3.719mm)],plaque thickness [(1.43±0.485mm)vs(0.92±0.343mm)] of MB segment were all increased dramatically compared with those of MCA segment(p<0.05).The EEMA [(19.06±5.926mm~2)vs(9.74±4.066mm~2)],PA [(9.52±3.42mm~2)vs(3.55±1.522mm~2)],PB[(64.37±12.921%)vs(44.08±12.889%)],plaque length [(39.94±13.401mm)vs(11.11±6.508mm)],plaque thickness [(1.43±0.485mm)vs(0.76±0.330mm)] of the proximal segment were increased markedly compared with those of the distal segment(p<0.05).There was a significance in the EEMA between the MCA and the distal segments [(6.30±1.995mm~2)vs(9.74±4.066mm~2)],(p<0.05).No statistical difference in PA [(4.92±2.177mm~2)vs(3.55±1.522mm~2)],PB[(50.07±10.498%)vs(44.08±12.889%)],plaque length [(8.08±3.719mm)vs(11.11±6.508mm)],plaque thickness [(0.92±0.343mm)vs(0.76±0.330mm)]between the MCA and the distal segments(p>0.05).There was no difference in LA during the three segments [(5.24±2.365mm~2)vs(4.75±1.985mm~2)vs(4.37±1.435mm~2)],(p>0.05).Conclusions 1.LAD MB locates at the middlemostly.2.MB always results in pathological disorders at the proximal segment of MB.3.Stenosis of the proximal MB is positively correlates with MCA’s contraction.4.Male is a independent predict factor of Nobel Classification. |
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