To test the hypothesis that concentration polarization of atherogenic lipids may occur in the arterial system and play an important role in localization of atherosclerosis, we simulated and measured in vitro the luminal surface concentration of low density lipoprotein (LDL) in local stenosis at the distal end of carotid artery by number simulation and laser scanning confocal microscopy, then we designed carotid stenosis model to test the role of LDL concentration polarization in atherogenesis. The in vitro experiment showed that the luminal surface LDL concentration was higher than the bulk concentration as predicted by the concentration polarization theory. The relative luminal surface LDL concentration changed with the flow velocity and ratio of stenosis. The wall concentration of LDL was highest in the round tube with 40% stenosis at the same velocity, while the wall concentration of LDL was higher when Re was 250 than Re was 500 at the same extent of narrowness. The animal experiment also revealed that general atherogenic plaques obviously occurred at the distal end of local stenosis where concentration polarized. The results strongly support our hypothesis that concentration polarization of lipoproteins occurs in local stenosis at the distal end of carotid artery, and this in turn promotes the localization of atherosclerosis which develops in the arterial system.
Animals ; Atherosclerosis ; physiopathology ; Carotid Stenosis ; physiopathology ; Disease Models, Animal ; Lipoproteins, LDL ; metabolism

OBJECTIVETo demonstrate the abnormal intima rotation pattern of the carotid atherosclerosis plaque using velocity vector imaging, and to develop a new method for the clinical mechanical state assessment of the plaque intima.

METHODSThe rotation movement and rotation angle on the serial dynamic ultrasonic short-axis gray scale views of 48 isolated atherosclerosis plaques (i. e., upstream, midstream, and downstream) and nearby reference segments of carotid artery in 46 patients were derived and analyzed using a dedicated velocity vector imaging workstation. The incidence of intima rotation movement and the rotation angle at different sections of the plaque and nearby reference segments before and after the standard grip stress test during systole and diastole respectively were counted and measured.

RESULTSBefore and after the stress test, the intima rotation movement occurred at the majority of the short-axis sections of the plaque and the nearby reference segments during cardiac cycle. Before the stress test, the incidence of intima rotation movement at the upstream section of the plaque during systole was significantly higher than that of reference segment (P = 0.036) The reversal direction of the intima rotation at those sections and reference segment during systole and diastole was demonstrated. After the stress test, the incidence of intima rotation movement at the midstream section of the plaque during diastole was significantly lower than that of reference segment (P = 0.031). The incidence of the intima rotation movement changed at the sections of upstream, midstream, and downstream of the plaque before and after the stress test also were explored (i. e., increased in systole and decreased in diastole) except the reference segment intima.

CONCLUSIONSThe intima rotation movement occurs at the majority of the isolated plaque and nearby reference segment, and the incidences of the intima rotation movement at the plaque is different from that of the reference segment during systole and diastole respectively. The abnormal pattern of intima rotation movement may be used to indicate the unstable mechanical state of the isolated plaque intima.

Carotid Arteries ; diagnostic imaging ; physiopathology ; Carotid Stenosis ; diagnostic imaging ; physiopathology ; Echocardiography, Stress ; Exercise Test ; Humans ; Rotation ; Tunica Intima ; diagnostic imaging ; physiopathology

OBJECTIVETo investigate the relationship between the carotid stenosis (CS) and the pulse pressure (PP) in elderly men with essential hypertension.

METHODSAccording to the Color Doppler Flow Imaging (CDFI), 157 elderly men with essential hypertension and carotid atherosclerosis were divided into five classifications and two groups: CS < 50% group (n = 66) and CS > or = 50% group (n = 91). The blood pressures were measured within one year before the CDFI was taken and clinical data were recorded.

RESULTS(1) The systolic blood pressure (SBP) and the PP in CS > or = 50% group were significantly increased than those in CS < 50% group, while the diastolic blood pressure (DBP) was converse. The independent risk factors of CS > or = 50% were peripheral arterial disease (OR: 4.543, 95%CI: 1.415-14.590) and PP (OR: 1.096, 95% CI: 1.038-1.157). (2) CS classifications positively correlated with PP (r = 0.402, P < 0.01) and fibrinogen (FIB) (r = 0.200, P < 0.05). After adjusting for age, body mass index (BMI), SBP, DBP, total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-c), high density lipoprotein cholesterol (HDL-c), fasting serum glucose (FBG), blood uric acid (UA), D-dimer, amino-terminal pro-brain natriuretic peptide (NT-proBNP), total bilirubin (TBIL) and direct bilirubin (DBIL), multiple regression analysis showed that PP and FIB remained as predisposing risk factors for CS classifications.

CONCLUSIONThe pulse pressure was correlated with carotid stenosis in elderly men with essential hypertension and it was justified for concurrent inhibition of PP in the treatment of high blood pressure.

Aged ; Aged, 80 and over ; Blood Pressure ; Carotid Stenosis ; complications ; diagnostic imaging ; physiopathology ; Humans ; Hypertension ; complications ; physiopathology ; Male ; Middle Aged ; Ultrasonography

OBJECTIVES: The aim of this study was to investigate the association of blood pressure levels with the common carotid artery intima-media thickness (CCA-IMT) and carotid plaques. METHODS: Data were obtained from 2,635 subjects, aged 50 years and over, who participated in the Community Health Survey (a population-based, cross-sectional study) in Dong-gu, Gwangju city between 2007 and 2008. Participants were categorized into three groups according to blood pressure levels; normotensives (<120/80 mmHg), prehypertensives (120-139/80-89 mmHg), and hypertensives (> or =140/90 mmHg). Prehypertensives were further categorized as low prehypertensives (120-129/80-84 mmHg) and high prehypertensives (130-139/85-89 mmHg). Carotid intima-media thickness and plaques were evaluated with a high-resolution B-mode ultrasound. Statistical analyses were performed using chi-square test, ANOVA, and multiple logistic regression. RESULTS: Prehypertensives had significantly greater maximal CCA-IMT values than normotensives, with a multivariate adjusted odds ratio of 1.78 (95% CI=1.36-2.32) for abnormal CCA-IMT (maximal CCA-IMT > or =1.0 mm), and 1.45 (95% CI=1.19-1.77) for carotid plaques. The multivariate adjusted odds ratio of low prehypertensives was 1.64 (95% CI=1.21-2.21) for abnormal CCA-IMT, and 1.30 (95% CI=1.04-1.63) for carotid plaques compared with normotensives. Subject with hypertension had higher frequency of abnormal CCA-IMT (odds ratio, 2.18; 95% CI=1.49-3.18), and carotid plaques (odds ratio, 1.98; 95% CI=1.46-2.67) compared with normotensives after adjustment for other cardiovascular risk factors. CONCLUSIONS: Our results indicate that there is a significant increase in the prevalence of carotid atherosclerosis in subjects with prehypertension (even in low prehypertensives) compared with normotensive subjects. Further studies are required to confirm the benefits and role of carotid ultrasonography in persons with prehypertension.
Aged ; *Blood Pressure ; Carotid Artery Diseases/physiopathology ; Carotid Artery, Common/*pathology/ultrasonography ; Carotid Stenosis/pathology ; Cross-Sectional Studies ; Female ; Humans ; Male ; Middle Aged ; Prevalence ; Tunica Intima/*pathology

OBJECTIVETo investigate the difference in the vulnerability of carotid atherosclerotic plaques in patients with unilateral and bilateral intraplaque hemorrhage (IPH).

METHODSA retrospective analysis was conducted among 44 patients with unilateral IPH (30 cases) or bilateral IPH (14 cases) in the carotid plaques detected by magnetic resonance imaging (MRI) in our hospital between December, 2009 and December, 2012. The age, maximum wall thickness and incidence of fibrous cap rupture were compared between the two groups.

RESULTSCompared with those with unilateral IPH, the patients with bilateral IPHs had a significantly younger age (66.6∓9.4 years vs 73.7∓9.0 years, P=0.027), a significantly greater maximum plaque thickness (6.3∓1.9 mm vs 5.0∓1.3 mm, P=0.035) and a higher incidence of ulcers (50% vs 13.3%, P=0.025). Logistic regression analysis revealed a significant association between bilateral IPHs and the occurrence of ulcer with an odd ratio (OR) of 6.5 (95% confidence interval [CI]: 1.5-28.7, P=0.014). After adjustment for gender in Model 1, bilateral IPHs were still significantly associated with presence of ulcer (OR=5.7, 95%CI: 1.1-29.2, P=0.036). But after adjustment for age (P=0.131) or maximum plaque thickness (P=0.139) in model 2, no significant correlation was found between bilateral IPHs and the presence of ulcer.

CONCLUSIONCompared with patients with unilateral IPH, those with bilateral IPHs are at a younger age and have a greater plaque burden and a higher incidence of fibrous cap rupture, suggesting a greater vulnerability of the carotid plaques in patients with bilateral IPHs.

Aged ; Carotid Arteries ; diagnostic imaging ; Carotid Stenosis ; diagnostic imaging ; physiopathology ; Fibrosis ; Hemorrhage ; diagnostic imaging ; Humans ; Magnetic Resonance Imaging ; Middle Aged ; Odds Ratio ; Plaque, Atherosclerotic ; diagnostic imaging ; Retrospective Studies

OBJECTIVETo evaluate hemodynamic character and surgical effect of stenoses or occlusion of carotid artery system by perfusion-weighted MRI.

METHODSTwenty-one patients with stenoses or occlusion of carotid artery system underwent surgical treatment. Two patients underwent endarterectomy, extracranial-intracranial arterial bypass to 10 patients, and percutaneous stent angioplasty to 9 patients.

RESULTSPreoperative perfusion-weighted magnetic resonance (MR) revealed normal regional cerebral blood flow in all patients, with delayed time to peak in both middle cerebral artery distribution and border zone. Postoperative perfusion-weighted MR revealed normal time to peak in border zone, but abnormal in middle cerebral artery distribution. Evaluated by perfusion-weighted MR, it showed that surgical method can improve the hemodynamic disorder of this kind of disease. The early curative effect of endarterectomy and percutaneous stent angioplasty is better than extracranial-intracranial arterial bypass.

CONCLUSIONSPerfusion-weighted MR is a good method to evaluate hemodynamic character of stenoses or occlusion of carotid artery system. Surgical method is helpful to this kind of disease, and its curative effect can be evaluated impersonally and accurately by this new technique.

Adult ; Aged ; Angioplasty ; Carotid Stenosis ; physiopathology ; surgery ; Cerebrovascular Circulation ; Endarterectomy, Carotid ; Female ; Follow-Up Studies ; Humans ; Magnetic Resonance Angiography ; methods ; Male ; Middle Aged ; Sensitivity and Specificity ; Treatment Outcome

OBJECTIVESTo establish a theoretical model for the tortuosity of internal carotid artery and summarize the hemodynamic rule of blood flow in a tortuous artery. To explore the relationship of cerebral ischemia and tortuous internal carotid artery.

METHODSTaking the internal carotid artery as a prototype, a geometric model of a tortuous artery was constructed according to the normal physiological and anatomical parameters of internal carotid artery. The boundary conditions and calculation conditions of blood flow are proposed. The numerical simulation of the blood flow in the tortuous artery is carried out with finite element method. Hemodynamic parameters of internal carotid artery were measured in 15 cases with the tortuosity of internal carotid artery and in 15 cases of normal control group. Blood pressure was measured by microcatheter connecting a pressure transducer at internal carotid artery, pre-tortuous and post-tortuous artery. The diameter and length of the above artery were measured and calculated by DSA machine.

RESULTSNumerical simulation results indicated pressure drop of blood flow and elongated length of artery is increased with diminution of the angle of tortuous artery. Clinical measurement data disclosed the same trend in the same curve as numerical simulation.

CONCLUSIONThe elongation and tortuosity of internal carotid artery results in decrease of blood pressure in the distal segment of tortuous internal carotid artery, kinking of internal carotid artery may be one of factors related to attack of cerebral ischemia on certain conditions.

Adult ; Aged ; Brain ; blood supply ; Brain Ischemia ; etiology ; physiopathology ; Carotid Artery, Internal ; physiopathology ; Carotid Stenosis ; complications ; physiopathology ; Female ; Finite Element Analysis ; Hemodynamics ; Humans ; Male ; Middle Aged ; Models, Cardiovascular ; Regional Blood Flow

OBJECTIVETo evaluate the validity of different treatment for minimizing the complications caused by hemodynamic changes during stenting angioplasty of carotid stenoses.

METHODSThere was no special measure for 80 of 205 cases during angioplasty. General blood pressure was controlled strictly to normal lower limit for avoiding intracranial reperfusion bleeding and angioplasty was done after elevated heart rate to 80 per minute in the remaining 125 cases.

RESULTSThere were 8.8% complications in 80 cases and no obviously complication occurred in 125 cases controlling hemodynamic changes. Follow-up period from 1 months to 5 years, there was no marked restenosis.

CONCLUSIONRegulating hemodynamic changes should be emphasized for reducing complications and improving the effect of carotid artery stenting.

Aged ; Aged, 80 and over ; Angioplasty, Balloon ; Blood Pressure ; physiology ; Carotid Stenosis ; physiopathology ; therapy ; Female ; Follow-Up Studies ; Heart Rate ; physiology ; Humans ; Male ; Middle Aged ; Monitoring, Intraoperative ; Stents

OBJECTIVETo explore the different effects of systolic blood pressure (SBP) and low density lipoprotein on carotid plaques (LDL-C).

METHODSA total of 101 510 serving and retired workers of a company who participated in the health examination in 2006-2009, 5852 participants were selected as study subjects by stratified random sampling according to the age and sex ratio. These subjects took their health examination in 2010-2011 including the carotid ultrasound. Finally, 5361 eligible participants with complete data were included in the analysis. The detection and weighted rates of carotid plaques were calculated for four groups: normal SBP and LDL-C group (3524 subjects), normal SBP and high LDL-C group (356 subjects), elevated SBP and normal LDL-C group (1308 subjects) and elevated SBP and high LDL-C group (173 subjects). The effects of different baseline SBP and LDL-C on detection rates of the carotid artery plaques were analyzed by logistic regression.

RESULTSThe detection rate of carotid plaques in normal SBP and LDL-C group, normal SBP and high LDL-C group, elevated SBP and normal LDL-C group, elevated SBP and high LDL-C group was 33.7% (1186/3524), 41.3% (147/356), 64.8% (847/1308), 68.8% (119/173) (χ(2) = 425.75, P < 0.05) and the weighted detection rate was 36.0%, 42.0%, 64.5% and 68.3% respectively. For men, the detection rate was 44.2% (877/1985), 51.1% (97/190), 70.6% (657/930), 71.3% (82/115) (χ(2) = 194.02, P < 0.05) and the weighted detection rate was 31.2%, 36.1%, 49.8% and 50.3% respectively. For women, the detection rate was 20.1% (309/1539), 30.1% (50/166), 50.3% (190/378), 63.8% (37/58) (χ(2) = 180.17, P < 0.05) and the weighted detection rate was 30.9%, 46.3%, 70.3%, and 88.1% respectively. After adjusted for other risk factors, the OR (95%CI) value was 1.37 (1.05 - 1.78), 2.05 (1.74 - 2.43) and 2.12 (1.45 - 3.12) for normal SBP and high LDL-C group, elevated SBP and normal LDL-C group and elevated SBP and high LDL-C group respectively compared with normal SBP and LDL-C group.

CONCLUSIONElevated SBP and high LDL-C were risk factors of the carotid artery plaques. Compared with high LDL-C, elevated SBP may add a higher risk for carotid plaques.

Adult ; Aged ; Blood Pressure ; Carotid Stenosis ; blood ; epidemiology ; physiopathology ; Cholesterol, LDL ; blood ; Dyslipidemias ; Female ; Humans ; Male ; Middle Aged ; Risk Factors ; Systole

OBJECTIVESTo explore influencing factors of regional cerebral blood flow (rCBF) in geriatric carotid stenosis, and to analyze changes of rCBF and clinical symptoms after carotid stenting.

METHODSDuring August 2005 and April 2008, 68 geriatric patients of carotid stenosis having SPECT examination in our hospital were retrospectively studied, whose diagnosis was approved by angiography. Correlated rCBF was compared separately in different stenotic degrees of carotid stenosis, in unilateral or bilateral stenosis, accompanied with vertebrobasilar stenosis (VBS) or not, with collateral circulation or not, before and after carotid stenting.

RESULTSWhen patients of unilateral carotid stenosis were grouped by different clinical factors, cases of patients with reduced rCBF were compared using chi(2) test: the P value was 0.046 and 0.020 when comparing group of stenotic degree 90% - 99% with group 70% - 89% and group 50% - 69%; the P value was 0.927 between group accompanied with VBS and group without; the P value was 0.222 between group with collateral circulation and group without. When comparing reduced rCBF cases between unilateral and bilateral carotid stenosis, the P value was 0.046. After carotid stenting, 76% of patients had their rCBF improved, and also the scores of presenting symptoms evaluated by modified Rankin scale were elevated from 1.4 +/- 0.7 on admission to 0.4 +/- 0.3 postoperatively (P < 0.001).

CONCLUSIONSThe research indicates that higher stenotic degree and bilateral carotid stenosis may cause rCBF decrease in geriatric carotid stenosis. Carotid stenting may improve rCBF and change clinical symptoms significantly.

Aged ; Aged, 80 and over ; Brain ; blood supply ; Carotid Stenosis ; physiopathology ; surgery ; Cerebrovascular Circulation ; Female ; Follow-Up Studies ; Humans ; Male ; Regional Blood Flow ; Retrospective Studies ; Stents