Résumé
Objective To assess the relationship between plaque burden (PB) and area strain (AS) by intravascular ultrasonic elastography (IVUSE).Methods Forty purebred New Zealand rabbits were fed with a high-cholesterol diet.And the abdominal aorta endothelium was balloon-injured after 2 weeks.At the end of the 12th week,2 plaques with moderate echo from each rabbit were chosen for in situ imaging,and 2 consecutive frames near the end-diastole images in situ were used to construct an IVUS elastogram.Cross-sectional external elastic membrane area (EEMare),lumen area (Lumenarea),plaque area (PA),PB,external elastic membrane volume (EEMvolume),lumen volume (Lumenvolume),plaque volume (PV),plaque volume burden (PVB),maximal plaque thickness (Tmax) and minimal plaque thickness (Tmin),eccentric index (EI),remodeling index (RI) and AS were measured and calculated,respectively.According to the PB,the plaques were divided into low PB group (PB≤40 ％) and high PB group (PB＞ 40 ％).The differences of all above parameters between the two groups were compared,and the relationship between the plaque morphological and mechanical parameters were analyzed.Results PA,PV,PB,PVB,Tmin,Tmax,Lumenarea,Lumenvolume and EI were different between the 2 groups (all P＜0.01).On stepwise multiple regression analysis,the regression equation were built,(Y)=-6.921+10.430X1 +12.207X2((Y):AS,X1:EI,X2:PB,R2 =0.272,P＜0.001).After eliminating the effect of EI on the AS,the lower PB group had obviously smaller AS than higher PB group (P =0.010).Conclusion The PB has effect on plaque mechanical stability.The plaques with higher burden are more vulnerable than those with lower burden.
Résumé
Objective To assess the relationship between plaque burden (PB) and area strain (AS) by intravascular ultrasonic elastography (IVUSE).Methods Forty purebred New Zealand rabbits were fed with a high-cholesterol diet.And the abdominal aorta endothelium was balloon-injured after 2 weeks.At the end of the 12th week,2 plaques with moderate echo from each rabbit were chosen for in situ imaging,and 2 consecutive frames near the end-diastole images in situ were used to construct an IVUS elastogram.Cross-sectional external elastic membrane area (EEMare),lumen area (Lumenarea),plaque area (PA),PB,external elastic membrane volume (EEMvolume),lumen volume (Lumenvolume),plaque volume (PV),plaque volume burden (PVB),maximal plaque thickness (Tmax) and minimal plaque thickness (Tmin),eccentric index (EI),remodeling index (RI) and AS were measured and calculated,respectively.According to the PB,the plaques were divided into low PB group (PB≤40 ％) and high PB group (PB＞ 40 ％).The differences of all above parameters between the two groups were compared,and the relationship between the plaque morphological and mechanical parameters were analyzed.Results PA,PV,PB,PVB,Tmin,Tmax,Lumenarea,Lumenvolume and EI were different between the 2 groups (all P＜0.01).On stepwise multiple regression analysis,the regression equation were built,(Y)=-6.921+10.430X1 +12.207X2((Y):AS,X1:EI,X2:PB,R2 =0.272,P＜0.001).After eliminating the effect of EI on the AS,the lower PB group had obviously smaller AS than higher PB group (P =0.010).Conclusion The PB has effect on plaque mechanical stability.The plaques with higher burden are more vulnerable than those with lower burden.
Résumé
Objective To assess the relationships between area strain (AS) and eccentric index (EI) of atherosclerotic plaques as seen by intravascular ultrasonic elastography (IVUSE),and to reveal the effect of EI on the plaques stability.Methods Forty purebred New Zealand rabbits were fed with a high-cholesterol diet;the abdominal aorta endothelium was balloon-injured after 2 weeks;at the end of week 12,2 plaques with moderate echo from each rabbit were chosen for in situ imaging,and 2 consecutive frames near the end-diastole images in situ were used to construct an IVUS elastogram.Results The eccentric plaques showed significantly greater area stain (AS) than the centripetal plaques [4.77(2.92,8.01)% vs 3.27(2.15,4.82)%,P=0.029] with smaller plaque area and plaque burden (P<0.05).The plaque AS was positively correlated with EI (r=0.392,P=0.003).The eccentric plaques showed significantly greater AS in the shoulder than in body [4.98(3.17,8.48)% vs 4.64(2.51,5.92)%,P=0.008].Conclusions The EI is one of influential factors on plaque AS.Eccentric plaques may be more vulnerable than centripetal plaques,especially in the shoulder of eccentric plaques which have greater AS than their body.