Abstract:

Objective     To study the correlation between characteristics  of unstable atherosclerotic plaques with intravascular ultrasound (IVUS) and monocyte chemotaxis. Methods     Forty patients with stable angina pectoris (SAP) and forty patients with unstable angina pectoris (UAP) were enrolled into the study. Coronary arteriography (CAG) and IVUS were performed in all patients. IVUS was used to analyze the qualities of the plaques and measure the external elastic membrane (EEM) area, lumen area（LA）, plaque area（PA）and plaque burden (PB%) at both the lesion and the reference segments in the same vessel. The lumen eccentricity index （EI）and remodeling index(RI) were calculated. Peripheral monocyte chemotaxis was assayed by the transwell chamber. Results     Soft lipid plaques were foundin 50% of patients with unstable angina , while the patients with stable angina mainly suffered from fibrous and mixed plaques(55%), and only 17 % soft plaques. There were more eccentric plaques in the unstable than the stable groups(P<0.05), and EEMA, LA, PA and PB in the unstable plaques were larger than those of stable plaques (all P<0.01). A positive remodeling pattern was identified in 68% (27/40) unstable plaques while 75%(30/40) stable plaques showed negative remodeling. The average number of migrated monocytes measured in UAP patients were more than that in patients with SAP(P<0.01). The UAP group showed a higher activity of monocyte chemotaxis ability. PB measured with IVUS correlated well with monocytes chemotaxis(γ=0.52，P<0.01). Conclusions    IVUS can detect unstable atherosclerotic plaques and predict plaque disruption in the early stage of atherosclerosis. Monocyte chemotaxis ability is associated with the stability of atherosclerotic plaques.

Key words: Intravascular ultrasound; Arteriosclerosis; Vulnerable plaque; Chemotaxis