Low Carotid Artery Wall Shear Stress is Associated with Significant Coronary Artery Disease in Patients with Chest Pain

Study on the characteristics of carotid wall shear stress in type 2 diabetes patients based on ultrasound vector flow imaging

Objectives

We aimed to quantitatively analyze wall shear stress (WSS) of the common carotid artery (CCA) and elucidate the relationship between WSS and cardiovascular disease (CVD) in patients with type 2 diabetes mellitus (T2DM) using ultrasound vector flow (V-Flow) imaging.

Methods

A total of 109 T2DM patients were selected as the DM group, while 49 healthy volunteers served as the control group. V-Flow examination of the bilateral CCA was conducted. The maximum wall shear stress (WSSmax) and mean wall shear stress (WSSmean) at the bifurcation, proximal bifurcation and middle segment of the bilateral CCA were obtained.

Results

The DM group showed decreased WSSmean in the middle region and proximal bifurcation of the CCA compared with the control group (p < 0.05). The WSSmean was further decreased in T2DM patients with CVD compared to those without CVD (middle region: 0.71 ± 0.17 Pa vs. 0.84 ± 0.24 Pa, p < 0.05; proximal bifurcation: 0.62 ± 0.22 Pa vs. 0.80 ± 0.21 Pa, p < 0.05). The receiver operating characteristic curve showed that a model combining with age, body mass index and WSSmean at the proximal carotid bifurcation had diagnostic value for detecting CVD in T2DM patients (area under the curve: 0.862, p < 0.05).

Conclusion

WSSmean has potential value for evaluation of atherosclerosis, as well as in detecting the occurrence of CVD in T2DM patients. Ultrasound V-Flow imaging may be an effective tool for non-invasive evaluation of WSS in the clinic.

Evaluating Total Atherosclerosis Burden of Baroreceptor-Resident Arteries after Ischemic Cerebrovascular Disease for Identifying Patients with Heavy Coronary Atherosclerosis Burden

AIM

The carotid sinuses and aortic arch are baroreceptor-resident arteries (BRAs) and atherosclerosis-susceptible sites of brain-supplying arteries, which would impair baroreflex-mediated blood pressure (BP) regulation and prompt coronary atherosclerosis. We sought to determine the relationship between total atherosclerosis burden (TAB) of BRAs and coronary atherosclerosis burden (AB) in patients with ischemic cerebrovascular disease (ICVD) and explore the potential contribution of BP profiles to this relationship.

METHODS

In this cross-sectional analysis of patients with ICVD who simultaneously undertook computed tomography angiography and 24-hour ambulatory BP monitoring, TAB of BRAs was scored based on the atherosclerotic vessel circumference ratio of the carotid sinuses and aortic arch, while the ABs of the intracranial, cervical, aortic, and coronary arteries were scored based on stenosis severity and plaque complexity as routine.

RESULTS

Among the 230 patients analyzed, coronary AB was significantly correlated with TAB of BRAs, independently of, and more tightly than the ABs of the intracranial, cervical, and aortic arteries, and the stenosis- and complexity-based AB of BRA-located arteries (bilateral common and extracranial internal carotid arteries and aortic arch). Both coronary AB and TAB of BRAs were negatively associated with the night-to-day BP dipping ratios, which was quite different from the relationship between intracranial AB and 24-hour BP characteristics. These findings were also true for patients with ICVD without a history of coronary artery disease.

CONCLUSION

Evaluating TAB of BRAs might provide a new link between atherosclerosis of brain- and heart-supplying arteries, connected partially by BP circadian rhythm. It might facilitate identifying patients with ICVD with heavy coronary AB and comprehensively managing vascular risk.

Biomechanical Forces and Atherosclerosis: From Mechanism to Diagnosis and Treatment

The article provides an overview of current views on the role of biomechanical forces in the pathogenesis of atherosclerosis. The importance of biomechanical forces in maintaining vascular homeostasis is considered. We provide descriptions of mechanosensing and mechanotransduction. The roles of wall shear stress and circumferential wall stress in the initiation, progression and destabilization of atherosclerotic plaque are described. The data on the possibilities of assessing biomechanical factors in clinical practice and the clinical significance of this approach are presented. The article concludes with a discussion on current therapeutic approaches based on the modulation of biomechanical forces.

[Carotid Wall Shear Rate as a Marker of Systemic Atherosclerosis and Atherosclerotic Cardiovascular Disease]

AIM

to assess possibility of the use of carotid wall shear rate (WSR) as a marker of systemic atherosclerosis and atherosclerotic cardiovascular disease (ASCVD).

MATERIALS AND METHODS

We included into this study 200 patients with different cardiovascular risk (142 patients already had one or more ASCVD). All patients underwent ultrasound scanning of carotid and lower limb arteries with measurement of the ankle-brachial index. Carotid WSR was determined during ultrasonic scanning of carotid arteries in accordance with the Hagen-Poiseuille law.

RESULTS

Mean WSR value in this cohort of patients was 434±139 s-1. Based on the results of the ROCanalysis, it was found that WSR below the threshold value of 300 s-1 allowed to predict the presence of ASCVD with sensitivity of 97.1 % and specificity of 84.6 %. WSR &lt;300 s-1 was associated with relative risk (RR) of ASCVD presence 11.2 (95 % CI 1.26-99.3, p=0.03), adjusted for factors such as sex, age, smoking, obesity, hypertension, estimated glomerular filtration rate (eGFR), low density lipoprotein cholesterol, and high sensitivity C-reactive protein, carotid intima-media thickness. The model which included carotid WSR, as well as factors such as the presence of type 2 diabetes, obesity, sex, age, eGFR, allowed to diagnose combined atherosclerotic lesions of peripheral arteries with a sensitivity of 73.1 % and a specificity of 90.3 %.

CONCLUSION

Evaluation of the carotid WSR allows to diagnose with satisfactory sensitivity and specificity the presence of combined atherosclerosis of peripheral arteries and ASCVD.

Association between Carotid Wall Shear Rate and Arterial Stiffness in Patients with Hypertension and Atherosclerosis of Peripheral Arteries

Aim

To evaluate carotid wall shear rate (WSR) in association with local and regional vascular stiffness in patients with hypertension (HTN) and atherosclerosis of peripheral arteries and to study the pattern of change of WSR in patients with HTN with increasing severity of peripheral artery atherosclerosis.

Materials and Methods

Study involved 133 patients with HTN, 65 men and 48 women, aged in average 57.9±10.8 years. All patients were divided into four groups in accordance with ultrasound morphologic classification of vessel wall. Duplex scanning of carotid and lower limb arteries was performed. Carotid-femoral (cfPWV) and carotid-radial (crPWV) pulse wave velocity (PWV) were measured. Local carotid stiffness was evaluated by carotid ultrasound.

Results

WSR of patients with plaques without and with hemodynamic disturbance was 416±128 s^-1 and 405±117 s^-1, respectively, which was significantly less than the WSR in patients with intact peripheral arteries - 546±112 s^-1. Decreased carotid WSR was associated with increased crPVW, cfPWV, Peterson's elastic modulus, decreased distensibility, and distensibility coefficient.

Conclusion

In patients with HTN and atherosclerotic lesions of peripheral arteries, it is registered that the carotid WSR decreased with increasing severity of atherosclerosis. Decreased carotid WSR is associated with increased local carotid stiffness, regional vascular stiffness of muscular, and elastic vessels.

Asymptomatic Plaques of Lower Peripheral Arteries and Their Association with Cardiovascular Disease: An Autopsy Study

Aims: Patients with peripheral artery disease (PAD) have a high prevalence of cardiovascular morbidity and mortality; however, majority of patients with PAD are asymptomatic. This study aimed to histologically evaluate whether asymptomatic, lower extremity artery plaques are associated with systemic atherosclerosis and the onset of cardiovascular disease (CVD) events using autopsy cases.

Methods: We histologically investigated the atherosclerotic plaques of the common iliac, common carotid, coronary, and renal arteries from 121 autopsy cases without symptoms of PAD (mean age: 67.6 years; 63% men; 83% non-CVD death). We evaluated the relationship between the degree of iliac artery atherosclerosis and that of other arteries, and also the presence of any CVD, myocardial infarction, stroke, and renal failure.

Results: Advanced atherosclerotic plaques (American Heart Association ≥ 4) were present in 86 (72%) common iliac arteries in these cases. These arteries also showed high frequencies of calcification (66%), intraplaque hemorrhage (42%), and plaque disruption (24%). These advanced lesions were associated with age (≥ 60 years), sex (male), hypertension, diabetes, and smoking habit (all P < 0.05). Additionally, it was significantly associated with CVD (odds ratio, 95% confidence interval; 6.2, 2.2–22), myocardial infarction (6.4, 1.2– 19), stroke (8.7, 1.7 –16), and renal failure/hemodialysis (5.8, 1.1 – 11). Cases with advanced iliac artery plaques had advanced coronary and carotid atherosclerosis.

Conclusion: These results indicate that asymptomatic advanced plaques are frequently observed in common iliac arteries, and are associated with generalized atherosclerosis and CVD events.

Wall Shear Rate Measurement: Validation of a New Method Through Multiphysics Simulations

Wall shear stress is known to affect the vessel endothelial function and to be related to important pathologies like the development of atherosclerosis. It is defined as the product of the blood viscosity by the blood velocity gradient at the wall position, i.e., the wall shear rate (WSR). The WSR measurement is particularly challenging in important cardiovascular sites, like the carotid bifurcation, because of the related complex flow configurations characterized by high spatial and temporal gradients, wall movement, and clutter noise. Moreover, accuracy of any method for WSR measurement can be effectively tested only if reliable gold standard WSR values, considering all the aforementioned disturbing effects, are available. Unfortunately, these requirements are difficult to achieve in a physical phantom, so that the accuracy test of the novel WSR measurement methods was so far limited to straight pipes and/or similar idealistic configurations. In this paper, we propose a new method for WSR measurement and its validation based on a mathematical model of the carotid bifurcation, which, exploiting fluid-structure simulations, is capable of reproducing realistic flow configuration, wall movement, and clutter noise. In particular, the profile near the wall, not directly measurable because affected by clutter, is estimated through a power-law fitting and compared with the gold standard provided by the model. In this condition, the WSR measurements featured an accuracy of ±20 %. A preliminary test on a volunteer confirmed the feasibility of the WSR method for in vivo application.