Pulse pressure, blood flow, and atherosclerosis

Comparison of Parameters for Assessment of Carotid Stiffness and Their Association with Carotid Atherosclerosis in Rural Australian Adults: A Pilot Study

Carotid stiffness has been associated with the development and progression of carotid artery disease and is an independent factor for stroke and dementia. There has also been a lack of comparison of different ultrasound-derived carotid stiffness parameters and their association with carotid atherosclerosis. This pilot study aimed to investigate the associations between carotid stiffness parameters (derived via ultrasound echo tracking) and the presence of carotid plaques in Australian rural adults. In cross-sectional analyses, we assessed forty-six subjects (68 ± 9 years; mean ± SD) who underwent carotid ultrasound examinations. Carotid stiffness was assessed by a noninvasive echo-tracking method, measuring and comparing multiple carotid stiffness parameters, including stroke change in diameter (ΔD), stroke change in lumen area (ΔA), β- stiffness index, pulse wave velocity beta (PWV-β), compliance coefficient (CC), distensibility coefficient (DC), Young's elastic modulus (YEM), Peterson elastic modulus (Ep), and strain. Carotid atherosclerosis was assessed bilaterally by the presence of plaques in the common and internal carotid arteries, while carotid stiffness was assessed at the right common carotid artery. β-stiffness index, PWV-β, and Ep were significantly higher (p = 0.006, p = 0.004, p = 0.02, respectively), whilst ΔD, CC, DC, and strain were lower among subjects with carotid plaques (p = 0.036, p = 0.032, p = 0.01, p = 0.02, respectively) comparing to subjects without carotid plaques. YEM and ΔA did not significantly differ among the groups. Carotid plaques were associated with age, history of stroke, coronary artery disease, and previous coronary interventions. These results suggest that unilateral carotid stiffness is associated with the presence of carotid plaques.

Mechanisms of the Osteogenic Switch of Smooth Muscle Cells in Vascular Calcification: WNT Signaling, BMPs, Mechanotransduction, and EndMT

Characterized by the hardening of arteries, vascular calcification is the deposition of hydroxyapatite crystals in the arterial tissue. Calcification is now understood to be a cell-regulated process involving the phenotypic transition of vascular smooth muscle cells into osteoblast-like cells. There are various pathways of initiation and mechanisms behind vascular calcification, but this literature review highlights the wingless-related integration site (WNT) pathway, along with bone morphogenic proteins (BMPs) and mechanical strain. The process mirrors that of bone formation and remodeling, as an increase in mechanical stress causes osteogenesis. Observing the similarities between the two may aid in the development of a deeper understanding of calcification. Both are thought to be regulated by the WNT signaling cascade and bone morphogenetic protein signaling and can also be activated in response to stress. In a pro-calcific environment, integrins and cadherins of vascular smooth muscle cells respond to a mechanical stimulus, activating cellular signaling pathways, ultimately resulting in gene regulation that promotes calcification of the vascular extracellular matrix (ECM). The endothelium is also thought to contribute to vascular calcification via endothelial to mesenchymal transition, creating greater cell plasticity. Each of these factors contributes to calcification, leading to increased cardiovascular mortality in patients, especially those suffering from other conditions, such as diabetes and kidney failure. Developing a better understanding of the mechanisms behind calcification may lead to the development of a potential treatment in the future.

Brachial pulse pressure is associated with the presence and extent of coronary artery disease in stable angina patients: a cross-sectional study

Background

Previous epidemiological evidence has identified many risk factors for coronary artery disease (CAD). Pulse pressure (PP) was reported to be associated with CAD. However, more attention was paid to aortic PP than to brachial PP. This cross-sectional study aimed to investigate the direct relationship between brachial PP and the presence and extent of CAD in stable angina patients.

Methods

We recruited a total of 1118 consecutive patients with stable chest pain suspected of CAD. After screening with exclusion criteria, 654 patients were finally included in our study. Every patient underwent both blood pressure measurement and selective coronary angiography. Univariate and multivariate analysis were performed to analyze the association between PP and the presence and extent of CAD.

Results

This study revealed that brachial PP was an independent correlate of multivessel CAD. In multivariate generalized linear regression model, increasing brachial PP (per 1 mmHg) were associated with the increased number of diseased vessels (β = 0.01, SE = 0.00, P < 0.0001). Binary logistic regression analysis further confirmed this association. The risk of multivessel CAD increased significantly in patients with brachial PP ≥ 60 mmHg (OR = 1.69, 95% CI = 1.14–2.48, P = 0.0084) and as per 1 mmHg increased in brachial PP (OR = 1.02, 95% CI = 1.01–1.03, P = 0.0002), independent of age, gender, body mass index (BMI), smoking, diabetes, hypercholesterolemia and creatinine (Cr). This association was still of statistical significance in subgroup analysis of hypertension and diabetes.

Conclusion

Increasing brachial PP was significantly and independently associated with increased risk of multivessel coronary disease in stable angina patients. The association of brachial PP with CAD was more pronounced in hypertension group than in non-hypertension one.

Arterial Stiffness is Independently Associated with Severity of Carotid Siphon Calcifications in Community-Dwelling Older Adults: The Atahualpa Project

BACKGROUND

Knowledge on the association between arterial stiffness and intracranial atherosclerosis is limited. Here, we aimed to assess whether the aortic pulse wave velocity (PWV)-used as a surrogate of arterial stiffness-might independently predict severity of carotid siphon calcifications (CSCs), used as a marker of atherosclerosis.

METHODS

Of 437 Atahualpa residents aged 60 years or older, 300 (69%) underwent head computed tomography (CT) (for CSC assessment), brain magnetic resonance imaging (for identification of neuroimaging signatures of cerebral small vessel disease [SVD]), and aortic PWV determinations (for arterial stiffness estimation). Ordinal logistic regression models were constructed to predict severity of CSC (as the dependent variable) according to levels of aortic PWV after adjusting for demographics, cardiovascular risk factors, and neuroimaging signatures of SVD.

RESULTS

Grade 1 CSC were noticed in 120 (40%) subjects, grade 2 in 84 (28%), grade 3 in 73 (24%), and grade 4 in 23 (8%). The mean PWV was 10.4 ± 1.8 m/s, which increased from 9.8 ± 1.3 to 11.1 ± 2.1 m/s in individuals with grades 1 and 4 CSC, respectively (P <.001). The most parsimonious ordinal logistic regression model adjusted for relevant confounders showed a significant association between aortic PWV and severity of CSC. In this model, a change of 1 unit of aortic PWV increased the odds of CSC severity by 1.22 (95% confidence interval 1.07-1.39; P = .004).

CONCLUSIONS

The monotonically increased odds of aortic PWV among subjects with different grades of CSC, suggest that aortic PWV may be a marker for identifying candidates for CT screening in the search of CSC.

The Role of Brachial Pulse Pressure as an Indicator of Intracranial Atherosclerosis: The Atahualpa Project

INTRODUCTION

Carotid siphon calcifications (CSC) are an important imaging marker of systemic atherosclerosis. Routine assessment of asymptomatic CSC may allow the implementation of intervention strategies before catastrophic cerebrovascular events occur.

AIM

To assess whether brachial PP determinations might independently predicts the presence and severity of CSC in community-dwelling adults.

METHODS

All Atahualpa residents aged ≥40 years were invited for the practice of a non-enhanced CT scan of the head, and those who signed the informed consent and had no contraindications for this exam were enrolled. The brachial PP was calculated by subtracting the mean diastolic pressure from the mean systolic pressure obtained from three different readings with individuals in the sitting position.

RESULTS

Of 830 eligible candidates, 663 (80%) were included. The mean brachial PP was 56.4 ± 19.9 mmHg; 182 persons (27.4%) had PP levels >65 mmHg. CT revealed Grade 1 CSC in 356 (54%), Grade 2 in 141 (21%), Grade 3 in 128 (19%), and Grade 4 in 38 (6%) subjects. Predictive margins of PP (delta method) were significantly lower in individuals with Grade 1 CSC than in the other groups. In the best adjusted linear model, PP levels increased up to 11.7 mmHg as the severity of CSC increased (β 11.71; 95% C.I. 5.36-18.08: p < 0.001).

CONCLUSION

This study provides evidence on the relationship between brachial PP levels and intracranial atherosclerosis. Calculation of the PP may be used for detecting candidates for CT screening, reducing costs during population-based surveys, particularly in remote areas.

Relationship between sum of the four limbs' pulse pressure and brachial-ankle pulse wave velocity and atherosclerosis risk factors in Chinese adults

The aim of the present study was to analyze the relationship between the sum of the four limbs' pulse pressure (Sum-PP) and brachial-ankle pulse wave velocity (baPWV) and atherosclerosis risk factors and evaluate the feasibility of Sum-PP in diagnosing atherosclerosis systemically. For the purpose, a cross-sectional study was conducted on the basis of medical information of 20748 adults who had a health examination in our hospital. Both Sum-PP and baPWV exhibited significant variations among different human populations grouped by gender, smoking, drinking, and age. Interestingly, Sum-PP had similar varying tendency with baPWV in different populations. And further study in different populations showed that Sum-PP was significantly positively related to baPWV. We also investigated the relationship between Sum-PP, baPWV, and cardiovascular risk factors, respectively. We found that both Sum-PP and baPWV had significant positive correlation with atherosclerosis risk factors while both of them were negatively related to HDL-c. In addition, there was a significant close correlation between Sum-PP and baPWV in the whole population (r = 0.4616, P < 0.0001). Thus, Sum-PP is closely related to baPWV and is of important value for clinical diagnosis of atherosclerosis.