Modelling of the in-stent thrombus formation by dissipative particle dynamics.

BACKGROUND: Stent implantation is a highly efficacious intervention for the treatment of coronary atherosclerosis. Nevertheless, stent thrombosis and other post-operative complications persist, and the underlying mechanism of adverse event remains elusive. METHODS: In the present study, a dissipative particle dynamics model was formulated to simulate the motion, adhesion, activation, and aggregation of platelets, with the aim of elucidating the mechanisms of in-stent thrombosis. FINDINGS: The findings suggest that stent thrombosis arises from a complex interplay of multiple factors, including endothelial injury resulting from stent implantation and alterations in the hemodynamic milieu. Furthermore, the results suggest a noteworthy association between in-stent thrombosis and both the length of the endothelial injured site and the degree of stent malposition. Specifically, the incidence of stent thrombosis appears to rise in tandem with the extent of the injured site, while moderate stent malposition is more likely to result in in-stent thrombosis compared to severe or minor malposition. INTERPRETATION: This study offers novel research avenues for investigating the plasticity mechanism of stent thrombosis, while also facilitating the clinical prediction of stent thrombosis formation and the development of more precise treatment strategies.

Influence of stent strut and its associated injury on thrombus formation: A dissipative particle dynamics study.

Vascular stent intervention is a pivotal treatment for coronary atherosclerosis, though in-stent thrombosis remains a significant postoperative complication with an unclear underlying mechanism. This study utilized dissipated particle dynamics analysis to investigate the impact of stent and its injury on platelet behavior. The findings suggest that thrombus formation upstream of the stent is mainly initiated by upstream arterial injury, which leads to increased platelet accumulation and activation in that area. While thrombosis downstream of the stent is more directly influenced by the stent itself. The morphology and size of in-stent thrombosis can vary significantly due to the different contributions of the stent and underlying injuries. Additionally, the volume of in-stent thrombosis is affected by the extent of the injury and the viscosity of platelets, showing a notable increase in volume with the lengthening of the injury area and rise in platelet viscosity. This study provides a novel theoretical framework for optimizing stent placement strategies and structural designs by examining the effects of stent struts and associated injuries on thrombus formation.

[Influence of diet behaviors on height among children and adolescents in China: a multiple level analysis].

OBJECTIVE: To categorize growth and development stages among children and adolescents based on height, and to explore the influences of diet behaviors on height during different growth and development stages. METHODS: Children and adolescents (7 to 18 years) with normal weights were selected using "Reference Norm for Screening Overweight and Obesity in Chinese Child and Adolescent" set up by WGOC in 2003 and "Reference Norm for Screening Underweight in Chinese Child and Adolescent" from the "2010 National Physical Fitness and Health Surveillance" data, and the variables of height and diet behaviors sorted. The growth and development stages were categorized using the hierachical cluster analysis, and the multilevel model was used to analyze influences of diet behaviors on height at different growth and development stages. RESULTS: Basis on height, there were 4 growth and development stages among the children and adolescents. In the boys, growth and development stages included Pre-GSS (growth spurt stage, GSS) including 7 to 10 years, GSS (11 to 12 years), Post-GSS (13 to 14 years), and growth stability stage (15 to 18 years); in the girls, the stages included the fast velocity GS (growth stage, GS) including 7 to 10 years, GS (11 to 12 years), Post-GS (13 to 15 years), and growth stability stage (16 to 18 years). The results of the multilevel model showed that the students' height in the urban areas were higher than in the rural areas (P<0.01), and the trend of difference between the urban and rural areas with the different growth stages was a parabola shape, the highest differences were 3.36 cm and 3.23 cm in the GSS and the fast velocity GS, respectively. There were significant influences of breakfast on height during the Pre-GSS and the fast velocity GS (P<0.01), and increased 0.40 cm and 0.57 cm, respectively. Excluding the stablility growth stage in the girls, drinking milk increased significantly height during the different growth stages (P<0.01), and the increases were gradual downtrend with the growth stages, the highest increase was 0.91 cm and 0.94 cm in Pre-GSS and the fast velocity GS, respectively. Eating eggs increased significantly height during all the growth stages (P<0.01), and the increases were the gradual uptrend with different growth stages. There were interaction effects among breakfast, drinking milk and eating eggs during the different growth stages, which was the gradual downtrend. CONCLUSION: Breakfast and drinking milk are conducive to growth during early adolescence, and the effect of eating eggs on growth is gradual uptrend with different growth stages.

[The association between body mass index, waist circumference with body fat percent, and abdominal fat rate in overweight and obese pupils].

OBJECTIVE: To study the association between body mass index(BMI), waist circumference (WC) with body fat percent, and abdominal fat rate in overweight and obese pupils. METHODS: Using convenience sampling, two primary schools of Dongcheng district in Beijing were selected in May 2010. A total of 162 overweight and obese pupils graded from 2 to 5 who met the criteria of overweight and obese were recruited based on the physical exam record of the school medical department in April. Their physical measurements were taken to measure body fat percent (PBF), abdominal fat rate and visceral fat level and BMI was calculated.Independent-sample t test and Wilcoxon rank sum test were applied to analyze the gender differences. Correlation analysis was used to explore the association between the indexes of fat distribution (PBF, abdominal fat rate and visceral fat level) and BMI and WC.Univariate regression analysis was conducted to determine the variance of three indexes of fat distribution explained by the independent variables. RESULTS: The PBF of overweight and obese pupils was (43.62 ± 2.98) %, the abdominal fat rate of them was (28.06 ± 6.02)%, the visceral fat level of them was 7.51 ± 3.43, BMI was (23.41 ± 2.83) kg/m(2). WC, PBF and abdominal fat rate were (78.57 ± 7.76) cm, (42.36 ± 2.56) % and (26.47 ± 5.39) % in boys and (73.34 ± 7.22) cm, (45.88 ± 2.26) %, (30.92 ± 6.07) % in girls. The difference in gender was significant (t values were -4.218, 8.751, 4.811, respectively, all P values <0.01). The visceral fat level of boys and girls were 8.86 ± 3.42 and 5.09 ± 1.70, with significant difference (Z = -7.08, P < 0.01). The correlation between PBF and BMI and the variance of PBF explained by BMI (r = 0.563, R(2) = 31.7%) were stronger than them with WC (r = 0.402, R(2) = 16.1%) (P < 0.01). The correlation between visceral fat levels and WC and the variance of visceral fat level explained by WC (r = 0.723, R(2) = 57.3%) were higher than them with BMI (r = 0.621, R(2) = 41.7%) (P < 0.01). CONCLUSION: The correlation and prediction ability of BMI and body fat percent were stronger than WC, while the correlation and prediction ability of WC and visceral fat were higher than BMI.

Effect of exercise rehabilitation on hemodynamic performance after carotid artery stenting: a numerical study.

A high in-stent restenosis rate and thrombosis have compromised clinical benefits after vascular stent placement. Exercise rehabilitation after stenting emerges as a promising and practical therapeutic strategy to improve the clinical performance of this therapy, although it remains controversial. The present study aimed to explore the impact of exercise training on hemodynamic performance after vascular stent implantation. Different 3-dimensional computational models based on the patient-specific carotids were constructed to calculate hemodynamic parameters, including flow velocity, time-averaged wall shear (TAWSS), oscillatory shear index (OSI) and relative residence time (RRT). The results demonstrated that exercise training increased TAWSS but decreased OSI and RRT in some cases after the intervention, and high-intensity exercise further suppressed the adverse blood flow. However, exercise training remarkably reduced TAWSS and elevated OSI and RRT in patients with mild stenosis at upstream of stented segment. Additionally, we discovered that the hemodynamic environment change induced by exercise training was not significant compared to the stent position in some cases. Exercise had a less beneficial impact on the disturbed blood flow after the distal common carotid artery (CCA) stenting. These findings highlighted that exercise-induced hemodynamic changes differ under different conditions. The exercise training for the intervention patients should only be performed after a comprehensive vascular function assessment.

Trends in blood pressure and body mass index among Chinese children and adolescents from 2005 to 2010.

BACKGROUND: The prevalence of obesity, based on body mass index (BMI), among Chinese children and adolescents has increased for decades, but the relationship between trends in blood pressure (BP) and increasing BMI has not been studied. METHODS: BMI and BP measurements of 391,982 children aged 7-17 years were obtained from surveys in 2005 and 2010. The mean change and 95% confidence intervals (CIs) of BP were calculated, and the association between BMI and BP was assessed by using analysis of covariance and direct adjustment with the BMI distribution of 2005 survey. RESULTS: The mean systolic BP (SBP) and diastolic BP (DBP) increased 1.5 mm Hg (95% CI = 1.4-1.7 mm Hg) and 1.1 mm Hg (95%CI = 1.1-1.2 mm Hg) for boys and 1.2 mm Hg (95% CI = 1.1-1.3 mm Hg) and 1.0 mm Hg (95% CI = 1.0-1.1 mm Hg) for girls from 2005 to 2010, respectively. After adjustment for BMI, SBP and DBP in 2010 were 0.8mm Hg (95% CI = 0.8-0.9mm Hg) and 0.8mm Hg (95% CI = 0.7-0.8mm Hg) higher than in 2005, respectively (all P < 0.01). With adjustment for difference in BMI distribution in 2005 and 2010, the mean increase of SBP decreased by 40.5% and that of DBP by 26.9%. CONCLUSIONS: BP among Chinese children and adolescents was on the rise from 2005 to 2010, which was consistent with the hypothesis that the rise in BP was in part attributable to the rise in BMI.