The ultrasonic characteristics of angiographical normal left main coronary artery observing with intravascular ultrasound

Objective To investigate the ultrasonic characteristics of angiographical normal left main (LM) branch of coronary artery observing with intravaseular ultrasound(IVUS). Methods Seventy-six patients whose coronary angiogram showed the lesions restricted only in left anterior descending (LAD) branch or left cireumflex(LCX) branch and no lesion was found in LM branch were enrolled and IVUS was performed. The plaque burden was measured and the quality of atherosclerosis was identified in lesion site of LAD or LCX by IVUS. Meanwhile,the absence or existence of lesions in LM was identified,and the quality of lesions was analyzed if it showing those existed lesions. The diameter and area of lumen in left main were measured and diameter and area of vessel were also measured. The plaque burden were measured for those who atheroselerosis existed in LM. Results IVUS showed 28 cases completely normal, 12 cases with intimal membrance hyperplesia,36 cases with plaque and 2 cases with intimal membrance flap in patients which LM was angiographically normal. Among those there were 30 eccentric plaques and 6 concentric plaques. For 36 patients whose lesions existed in LM observed by IVUS,there were 25 cases (69.4%) with soft plaque,4 eases (11.1%) with fibrous plaque,2 cases (5.6%) with calcific plaque,5 cases (13.9%)with mixed plaque. IVUS showed lumen diameter was (5.32±0.68)mm and lumen area was (23.34±5.27)mm2 for female patients; and lumen diameter was (5.90±0.50)mm and lumen area was (27.75±4.47)mm2 for male patients. The difference had significane when comparing lumen diameter and lumen area between male and female patients (P=0.042 and P=0.048, respectively). Vessel diameter was (5.90±0.47)mm and vessel area was (27.58±4.21)mm2 in patients with intimal membrance hyperplesia; lumen diameter was (4.39±0.54)mm and lumen area was (17.45±5.23)mm2,vessel diameter was (5.99±0.67)mm and vessel area was(26.61±6.27)mm2 n patients with atherosclerotic plaque.Diameter stenosis percentage was(26.17±7.87)%and plaque burden was(34.79±9.37)%in LM.Conclusions IVUS can find those lesions in LM which CAG cannot detect and identify the quality and severity of lesion precisely. Key words: Endosonography; Microbubbles; Coronary arteriosclerosis; Coronary angiography