A comparison of passive and active wall mechanics between elastic and muscular arteries of juvenile and adult rats

Investigating the relationship between residual stress and micromechanical properties of blood vessels using atomic force microscopy

The magnitude of vascular residual stress, an inherent characteristic exclusive to the vasculature, exhibits a strong correlation with vascular compliance, tensile resistance, vascular rigidity, and vascular remodeling subsequent to vascular transplantation. Vascular residual stress can be quantified by evaluating the magnitude of the opening angle within the vascular ring. For decellularized vessels, the vascular ring's opening angle diminishes, consequently reducing residual stress. The decellularization process induces a laxity in the vascular fiber structure within decellularized vessels. To investigate the interrelation between the magnitude of residual stress and the microstructure as well as mechanical properties of elastin and collagen within blood vessels, this study employed fresh blood vessels, stress-relieved vessels, and sections of decellularized blood vessels. Structural scanning and force map experiments on the surface of the sections were conducted using atomic force microscopy (AFM). The findings revealed well-organized arrangements of elastin and collagen within fresh vessels, wherein the regularity of collagen and elastin exhibited variability as residual stress declined. Furthermore, both stress-relieved and decellularized vessel sections exhibited a reduction in the mean Young's modulus to varying extents in comparison to fresh vessels. The validity of our experimental results was further corroborated through finite element simulations. Hence, residual stress assumes a crucial role in upholding the structural stability of blood vessels, and the intricate association between residual stress and the microstructural and micromechanical properties of blood vessels holds significant implications for comprehending the impact of vascular diseases on vascular structure and advancing the development of biomimetic artificial blood vessels that replicate residual stress. RESEARCH HIGHLIGHTS: In this inquiry, we scrutinized the interconnection amid vascular residual stress and the microscale and nanoscale aspects of vascular structure and mechanical function, employing AFM. We ascertained that residual stress assumes a pivotal role in upholding vascular microstructure and mechanical attributes. The experimental outcomes were subsequently validated through finite element simulation.

Clinical impact of cardiovascular calcifications on stroke incidence in primary prevention: analysis in NADESICO study

The utility of assessment of cardiovascular calcifications for predicting stroke incidence remains unclear. This study assessed the relationship between cardiovascular calcifications including coronary artery calcification (CAC), aortic valve (AVC), and aortic root (ARC) assessed by coronary computed tomography (CT) and stroke incidence in patients with suspected CAD. In this multicenter prospective cohort study, 1187 patients suspected of CAD who underwent coronary CT were enrolled. Cardiovascular events including stroke were documented. Hazard ratio (HR) and confidence interval (CI) were assessed by Cox proportional hazard model adjusted for the Framingham risk score. C statistics for stroke incidence were also examined by models including cardiovascular calcifications. A total of 980 patients (mean age, 65 ± 7 years; females, 45.8%) were assessed by the CAC, AVC, and ARC Agatston scores. During a median follow-up of 4.0 years, 19 patients developed stroke. Cox proportional hazard model showed severe CAC (Agatston score ≥ 90th percentile [580.0 value]) and presence of AVC and ARC were associated with stroke incidence (HR; 10.33 [95% CI; 2.08-51.26], 3.08 [1.19-7.98], and 2.75 [1.03-7.30], respectively). C statistic in the model with CAC and AVC severity for predicting stroke incidence was 0.841 (95% CI; 0.761-0.920), which was superior to the model with CAC alone (0.762 [95% CI; 0.665-0.859], P < 0.01). CAC, AVC, and ARC were associated with stroke incidence in patients suspected of CAD. Assessment of both CAC and AVC may be useful for prediction of stroke incidence.

Novel Payloads to Mitigate Maladaptive Inward Arterial Remodeling in Drug-Coated Balloon Therapy

Drug-coated balloon therapy is a minimally invasive endovascular approach to treat obstructive arterial disease, with increasing utilization in the peripheral circulation due to improved outcomes as compared to alternative interventional modalities. Broader clinical use of drug-coated balloons is limited by an incomplete understanding of device- and patient-specific determinants of treatment efficacy, including late outcomes that are mediated by postinterventional maladaptive inward arterial remodeling. To address this knowledge gap, we propose a predictive mathematical model of pressure-mediated femoral artery remodeling following drug-coated balloon deployment, with account of drug-based modulation of resident vascular cell phenotype and common patient comorbidities, namely, hypertension and endothelial cell dysfunction. Our results elucidate how postinterventional arterial remodeling outcomes are altered by the delivery of a traditional anti-proliferative drug, as well as by codelivery with an anti-contractile drug. Our findings suggest that codelivery of anti-proliferative and anti-contractile drugs could improve patient outcomes following drug-coated balloon therapy, motivating further consideration of novel payloads in next-generation devices.

Myocardial infarction impaired wall mechanics and hemodynamics in peripheral arteries

Myocardial infarction (MI) impaired both cardiac functions and peripheral arteries. The changes in normal and shear stresses in the peripheral artery wall are of importance for understanding the progression of MI-induced heart failure (HF). The aim of the study is to investigate the corresponding changes of normal and shear stresses. The coronary artery ligation was used to induce the MI in Wistar rats. The analysis of wall mechanics and hemodynamics was performed based on in vivo and in vitro measurements. Myocardial infarction increased wall stiffness in elastic carotid and muscular femoral arteries significantly albeit different changes occurred between the two vessels from 3 to 6 weeks postoperatively. Moreover, the hemodynamic analysis showed the gradually deteriorated wall shear stress, oscillatory shear index and relative residence time in the two arteries. This study probably shed light on understanding the interaction between abnormal systemic circulation and peripheral mechanics and hemodynamics during the development of MI-induced HF.