| BackgroundWith the development of society and the improvement of the quality of life, The prevalence of coronary heart disease (CHD) become higher,and how to diagnosis CHD attracts more and more attention of people and physician. So that the accurate estimation of coronary lesions is very important in coronary heart disease diagnosis and treatment. Coronary angiography (CAG) can demonstrate narrow degree of coronary vascular cavity. For a long time, CAG has long been considered "gold standard"in CHD diagnosis and treatment. However, this technique can only provide the lumen of the two-dimensional image displaying wall plaques and vascular remodeling, while with the restrictions of the projection angle.Thus, CAG may have underestimated the severity of coronary artery stenosis, not even the correct diagnosis of lesions are some inevitable defects existing in the evaluation of coronary artery disease. While the emergence of intravascular ultrasound imaging technology (IVUS) make up for the above defects.High-frequency ultrasound probe inserted into the coronary artery, through real-time ultrasound imaging can fully display the cross-sectional images of the coronary artery.The IVUS not only can display vessel wall, but also can display the coronary lumen, plaque size, plaque composition and plaque morphology much more clearly.It is an important guiding role in the diagnosis and treatment of coronary lesions.So the IVUS have been said"biopsy". In recent years, the study found that acute coronary syndrome (ACS) occurs in the coronary artery with mild to moderate stenosis in patients with intermediate lesions.Acute myocardial infarction coronary angiography showed that65%patients with coronary artery diameter stenosis is less than50%and85%patients with coronary artery internal diameter stenosis is less than70%. It is indicating that atherosclerosis (AS) is a stable and unstable periods alternating nonlinear process.This process depends on the stability of the plaque rather than plaque size. Stable plaques don’t produce any symptoms or only angina pectoris,while the vulnerable plaque can lead to sudden cardiac death and the occurrence of ACS. The vulnerable plaque rupture and thrombosis is the main pathogenesis of ACS.Many studies show that the majority of patients with coronary artery disease exist one or more risk factors,however, traditional risk factors can not explain all of sudden coronary event.so more and more scholars look for other risk factors, many researchers focused on the inflammatory factors involved in the occurrence of coronary emergencies, so far the inflammation has been recognized as the main factors in AS the occurrence and progression.A variety of inflammatory factors involved in atherosclerotic plaque formation and progress. CD36, Fractalkine and lipoprotein related phospholipids enzyme A2(LP-PLA2)were proved to be involved in the occurrence and development of plaque instability. In this study, we found that between severe lesion group and intermediate lesion group, the plaque characteristics of IVUS and the inflammation factors levels of CD36is different.It is proved that intermediate lesion plaque is vulnerabe, the IVUS may provide help for the diagnosis and further treatment of coronary lesions.Objective1. To elucidate the clinical application value of intravascular ultrasound(IVUS) in assessing intermediate lesions2. To elucidate the relationship between serum levels of fractalkine, CD36and LP-PLA2and severity of coronary artery atherosclerosis.MethodsOne hundred and twenty patients with unstable angina underwent coronary angiography. Then the patients were divided into two groups:severe lesion group (lumen diameter stenosis greater than70%, including40patients), and the intermediate lesion group (lumen diameter stenosis50%-70%, including80patients). The two groups patients were treated with the Boston scientific production the iLab type intravascular ultrasound to check for lesions. The intravascular ultrasound probe is3.2F and frequency is40MHz. The0.014-inch guidance steel wire sent to the far end vascular lesions, after that we insert IVUS detector along the wire guided in imaging guidance to narrow distal part vessel. Then pull back IVUS detector to measure each index, such as the external elastic membrane area (EEMA), lumen area (LA), plaque area (PA), plaque burden (PB), and vascular remodeling index. IVUS were performed in all patients to analysis the coronary lesions. According to the formula to calculate the eccentric index (EI), plaque burden (PB) and remodeling index (RI):EI=(Dmax-Dmin)/Dmax, PB=PA/EEMA x100%, RI=EEMA (pathologic part)/EEMA (average proximal and distal reference vessel). According to typical angina symptoms and the change of ECG,It is showed that lesions are ischemic target blood vessels (namely the criminal blood vessels), IVUS display plaque burden≥70%. Patients confirming to the above standard were conducted with the coronary interventional therapy, otherwise did not receive the interventional therapy. Under aseptic conditions5ml venous blood was extracted, serum samples was preserved in-80℃in the refrigerator for application. Concentrations of CD36, fractalkine and LP-PLA2were measured by means of ELISA.Group data were analyzed with the use of SPSS17.0for windows. The measurement data with conform to the normal distribution are expressed as mean±D.Data which do not accord with normal distribution data were analyzed using the parametric test Mann-Whitney inspection.The Count data were analyzed using chi-square test, A value of P<0.05was considered statistically significant.Results1. The two groups demostrated no significant difference about the age, gender, smoking history, family history and high cholesterol. The hypertension, diabetes, and neutrophil cell ratios of intermediate lesions were lower than those of the severe lesions group (P<0.05) 2. The lipid plaque number of severe lesions group was significantly less than that of the intermediate lesions group (P<0.01); The calcified plaque and mixed plaque number were more than those of the intermediate lesions group (P<0.05).3. Patients with severe lesions had significantly larger external elastic membrane area (EEMA), plaque area (PA) and plaque burden(PB) than those of patients with intermediate lesions (P<0.05)4. According to the results in IVUS display plaque burden≥70%were intervented treatment.The external elastic membrane area (EEMA), lumen area (LA), plaque area (PA), plaque burden (PB), and eccentric index (EI), remodeling index (RI) were larger than those of the non-intervention group (P<0.05).5. Serum CD36level in the intermediate lesions guroup is lower than that of the severe lesions group (P<0.05); There is no significant difference between fractalkine and LP-PLA2.(P>0.05).ConclusionsIn this study, through the comparative study by IVUS and serology tests between the intermediate lesions and severe lesions.we found that,the intermediate lesions of patients with unstable angina have a typical vulnerable plaque characteristics, and IVUS can guide coronary intervention of intermediate lesions. CD36can be used as the evaluation of coronary artery atherosclerotic plaque vulnerability index. |
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