| Objectives: Using IVUS, we aimed to study the plaque morphology and distribution as well as composition and their effects on interventional treatment, understand the pathologic basis of acute coronary syndrom, evaluate the value of IVUS guided stent implantation, and investigate the factors related to in-stent restenosis. Methods:( 1)113 patients (male 78, mean age 63+12 years) underwent coronary artery angiography(CAG) and IVUS examinations. The target lesion location from angiography was the left anterior descending artery(LAD) in 68 patients, left circumflex artery in 13 and right cooronary artery in 32. Among them only 98 patients recieved stent implantation and 54 stented patients were performed follow up CAG and IVUS after six months. (2)After angiography and aditional administration of heparin(3000U), a 0.014-in, guide wire was passed over the target lesion and IVUS imaging catheter was introduced over the guidewire to about 10mm beyond the target lesion. WUS imaging was performed using a 2.9-3.5 Fr monorail system with 30-MHz mechanical transducer-tipped catheter( Boston Scientific Corporation, Boston,Massachasetts). All images were obtained with a manual or automatic pullback system at 0.5mm/s. Pullback was started from a position about 10mm distal to target lesion to aorto-ostial junction. On-line quantitative measurements were made during diastole stage and off-line measurements were performed from a 1/2-inch high resolution Super VHS videotape(Sony, Tokyo, Japan) which recorded the æ¡°v? EVAtft~A~ Abstract PIUS images simultaneously. LVUS studies were performed after administration of 0.2mg of intracoronary nitroglycerin. 6 segments were identified and analyzed: 1 .the proximal reference segment, 2.the target lesion, 3. the proximal body of the stent, 4. the distal body of the stent, 5. the distal reference segment,. 6.the left main coronary artery. Results:(l) 101 (89%) proximal reference segments , 103 (91%) distal reference segments and 51(63%) left main coronary artery segments which presented normal in angiography were abnormal from PIUS, and their percent cross-sectional narrowing were 45.9% ?12.9%, 39.2 ? 13.3% and 40.6?18.3%, respectively. (2) PIUS showed that 58(51%) target lesions were eccentric, among them 17 lesions(29%) had residual nondiseased vessel wall. Compared with target lesions, 186 non-target lesions(73%) presented eccentric and 72(39%) of them had residual nondiseased vessel wall(P<0.0 1). Among 113 high grade stenosis segments, 58 (51%) segments were consided to be positive remodeling and 21(19%) segments were consided to be negative remodeling, the others were consided to be no significant remodeling. (3) IVUS detected 65 (58%)target lesions calcification, which was only superficial in 35(54%), only deep ml 1(17%), and mixed in 19(29%). The mean calcium arc of target lesions was 112?060 . Compared to target lesions, 59(29%) reference lesions had calcification which showed only superficial in 41(70%), only deep in 6(10%), and mixed in 12(20%). The mean calcium arc of reference lesions measured 68 ?65 0 (P<0.0 1 ).However, fluoroscopy only found 20(18%) target lesions calcification(P<0.01 versus IVUS). (4) Compared with patients with stable angina, 48(84%) patients with unstable angina and 30(88%) patients with acute myocardial infarction had soft plaque(P<0.01) and 6(1 1...
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