Different Degrees Of Stenosis Research Articles

The value of whole-brain CT perfusion imaging combined with dynamic CT angiography in the evaluation of pial collateral circulation with middle cerebral artery occlusion.

Middle cerebral artery (MCA) occlusion is extremely common, especially unilateral artery, which can result in a significant incidence of cerebral infarction. To assess the value of whole-brain computed tomography perfusion (CTP) imaging combined with dynamic CT angiography (dCTA) in the evaluation of pial collateral circulation in patients with MCA occlusion. Whole-brain CTP and dCTA images were acquired in 58 patients with unilateral MCA occlusion. All patients were divided into three groups according to the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) collateral score (by CTA). The CTP parameters were analysed, including relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), relative mean transit time (rMTT), and relative time to peak (rTTP). Patients were followed up with the modified Rankin scale (mRS). All cases in this study were confirmed by DSA. The CTP parameters of the MCA blood supply area on the affected side of patients with different degrees of stenosis were significantly different from those on the unaffected side. There are significant differences in the CTP parameters and openings of the Willis circle in patients with different degrees of stenosis. Significant differences were found in the number of patients with good prognosis. Whole-brain CT perfusion combined with dynamic CTA can structurally and functionally evaluate the establishment of pial collateral circulation and its effect on cerebral hemodynamic changes.

Whole-Brain Volume CT Angiography can Effectively Detect Early Ischemic Cerebrovascular Diseases.

To investigate the role of whole-brain volume computed tomography (CT) perfusion in assessing early ischemic cerebrovascular diseases. Seventy-two patients with early ischemic cerebrovascular diseases who had undergone routine CT scan and 320-row volume CT whole-brain perfusion imaging within 8 h after admission were retrospectively enrolled in this one-center case-sectional study. The perfusion parameters of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and dynamic CT angiogram (4D-CTA) were obtained and analyzed. Among 72 patients, 29 cases with 37 cerebral ischemic lesions were found in plain CT scan, whereas 51 cases with 76 lesions were found in whole-brain CT perfusion, with 30.6% more patients being detected. The CBF value was significantly lower in the abnormal than normal corresponding perfusion area in the healthy hemisphere (P<0.05), while the MTT and TTP values were significantly higher in the abnormal than the normal corresponding area (P<0.05). 4D-CTA image suggested that 59 cases had different degrees of stenosis or occlusion, including 11 mild, 18 moderate, 21 severe, and 9 occlusive cases. Four-D-CTA imaging could detect significantly (P<0.05) more patients with abnormal perfusion in severe cerebral vascular stenosis or occlusion than those with no, mild or moderate stenosis (93.33% vs. 16.67%) (P<0.05). The stenosis of intracranial and carotid arteries was positively correlated with MTT and TTP values (P<0.05). Whole-brain volume CT angiography can comprehensively display early cerebral ischemic lesions, cerebral blood perfusion status, and cerebral vascular stenosis, providing valuable information for early detection of ischemic cerebral diseases and appropriate treatment planning.

Blood Flow Acoustics in Carotid Artery

This paper aims to identify and study the blood flow and acoustics characteristics of different degrees of stenosis in the carotid artery. Blood flow will produce acoustics, but the presence of different levels of stenosis are expected to produce different acoustic characteristics. The blood flow and acoustic characteristics are simulated by using computational fluid dynamics software (CFD). Several three-dimensional models of carotid arteries that have different degrees of stenosis are used together with a normal/healthy carotid artery - i.e., 30% and 70% degrees of blockage. The geometry of 30% and 70% stenosed model are computationally generated from a normal carotid artery geometry. In addition, the blood viscosity level was also increased in this study to a value of 0.005 kgms-1 (from the normal viscosity of 0.004 kgms-1) to compare the effect of hyperglycaemia (i.e., diabetes mellitus) that may bring additional complications to blood flow. Pulsatile simulations are used for all cases in order to mimic the exact blood flow condition in which the inlet velocity and outlet pressure change with time. The present study shows that as the degree of stenosis increases at the common carotid artery (CCA), the velocity at the internal carotid artery (ICA) and external carotid artery (ECA) outlet increases. The maximum velocity changes for ICA at the systolic peak from normal to 70% degree of stenosis for carotid artery shows an increase by 8%, while an opposite trend is observed for the maximum velocity changes of ECA at the systolic peak, where a reduction by 3% occurs from normal to 70% degree of stenosis for carotid artery. In terms of viscosity, as the viscosity of the blood increases, the velocity of the blood flow decreases in all geometry carotid arteries and may potentially provide further complications on clinical problems. The acoustic simulation showed that the acoustic power increases by 5% and 20% for carotid artery geometry that has 30% and 70% degree of stenosis, respectively. The present study indicates potential for further developing non-invasive acoustic means to diagnose and measure stenosis in carotid arteries.

A novel molecular communication inspired detection method for the evolution of atherosclerosis

Background and objective: Atherosclerosis is a leading cause of potentially serious cardiovascular diseases such as heart attack, stroke, and peripheral artery disease. Due to the prolonged and non-reversible process of thickening arteries walls, atherosclerosis plaques in the blood vessels are formed that restrict the blood flow. Early detection plays a vital role in minimizing the risk as there is no reliable method to detect the early stage of the disease. This paper proposes a novel atherosclerosis detection method based on the emerging paradigm of molecular communications. The work could pave the way to implement a low-cost and straightforward early detection method of atherosclerosis in the future.Methods: We used COMSOL to model the physical field, coupled the fluid module and the fluid particle tracking module, and mapped the contrast agent into nanoparticles (NPs). The NPs are released at the entrance of the blood vessel and received at the exit of the blood vessel, while NPs are propagating through different arterial stenosis. The arrival probability of NPs is defined as the ratio of the number of NPs that reach the outlet to the total number of released NPs. As a result of atherosclerosis, the arrival probability of Nps is affected by the dynamic flow nature changes, thereby reflecting the arterial stenosis degree. Furthermore, we introduce the multi-release method in this study, which has a similar concept of Inter-symbol interference in traditional communication. This multi-release method leads the overlapping concentrations of NPs remaining in the vessels and enhances the differences of arrival probability in different degrees of stenosis, which increases the chance of more observable results.Results: The assessment of arterial stenosis degree can be from the early stage to the late stage of the disease. To evaluate the arterial stenosis degree, we analyzed the Poincaré maps, representing the arrival probability of NPs at different arterial stenosis. Moreover, we could directly use data to quantify the pathological process at various stages. The difference between the data results obtained through multiple release methods is more prominent than a single-released method.Conclusions: This research proposes a new atherosclerosis detection method based on molecular communication, that is, to evaluate the arterial stenosis degree by modelling and using statistical data of NPs emission and reception in blood vessels. This method can not only use a simple method to detect the early stage of the disease. In addition, we can directly use data to quantify the pathological process of each stage, which is straightforward to assist doctors and may reduce the labour cost of traditional detection.

Doppler Ultrasonography Derived Maximal Systolic Acceleration: Value Determination With Artificially Induced Stenosis.

BackgroundIn diagnosing peripheral arterial disease (PAD), medial arterial calcification (MAC) hampers arterial compression and could lead to unreliable ankle brachial index (ABI), toe brachial index (TBI) and toe pressure (TP). Doppler ultrasonography (DUS) derived maximal systolic acceleration (ACCmax) might be more accurate to diagnose PAD. In an in vitro study, a strong correlation between ACCmax and the severity of stenotic disease was determined. The aim of this study was to investigate the ACCmax in correlation with conventional non-invasive diagnostics in an in vivo setting. Methods: In twelve healthy individuals, an arterial stenosis was mimicked by compression on the common femoral artery by an ultrasounds probe, creating a local stenosis of 50%, 70% and 90%. The ABI, TBI, TP and several DUS parameters (including ACCmax) were assessed at the ankle during these different degrees of stenosis. All DUS parameters were measured separately by two observers to determine the interobserver variability. Results: Overall the ABI, TBI, TP, ACCmax, ACCsys and PSV decreased significantly when the degree of stenosis increased. The ACCmax showed the highest correlation with the degree of stenosis (r −.884), compared to ABI (r −.726), TBI (r −.716) and TP (r −.758). Furthermore, the interobserver variability of ACCmax was excellent, with an intraclass correlation coefficient (ICC) of .97. Conclusion: ACCmax is an accurate non-invasive DUS parameter to diagnose and assess the severity of a mimicked arterial stenosis in healthy individuals. Further prospective assessment of the clinical value of ACCmax and its potential benefits in patients with PAD is needed.

Efficacy and safety of Montgomery T-tube placement for benign complex subglottic tracheal stenosis: a retrospective analysis of 29 cases

Objective: To analyze the efficacy and safety of Montgomery T-tube (T-tube) placement for benign complex subglottic tracheal stenosis. Methods: A retrospective analysis of the clinical data of 29 patients with benign complex subglottic tracheal stenosis receiving T-tube placement in Beijing Tiantan Hospital from May 2015 to December 2019. The causes were postintubation tracheal stenosis [27 cases (93.1%), including 21 cases (72.4%) of tracheal stenosis after tracheotomy, 6 cases (20.7%) of tracheal stenosis after tracheal intubation], cervical post-traumatic tracheal stenosis (1 case, 3.4%) and tuberculous tracheal stenosis (1 case, 3.4%), respectively. Three-dimensional reconstruction of tracheal computerized tomography (CT) and bronchoscopy were used to grade the stenosis according to Cotton-Myer classification system before bronchoscopic intervention. The degree of stenosis was Cotton-Myer grade Ⅱ (7 cases, 24.1%), grade Ⅲ (11 cases, 37.9%) and grade Ⅳ (11 cases, 37.9%), respectively. All cases received placement of T-tubes and follow-up. Fisher's exact test was used for comparison between groups. Results: T-tube placement was performed 39 times in 29 patients. T-tubes were successfully placed for 24 cases (82.8%). The main complication during the operation was tracheal mucosal tear (6 cases, 20.7%), which resolved in all cases within 2 weeks. The main postoperative complication was secretion retention (27 cases, 93.1%), which was relieved after home nebulization treatment in 26 cases; and followed by granulation hyperplasia, especially located in T-tube upper margin (12 cases, 41.4%), of which 8 cases were cured after bronchoscopic intervention. None of the patients had T-tube migration. There were no statistically significant differences in the success rate of T-tube placement and the incidence of major complications in patients with benign complex subglottic tracheal stenosis with different degrees of stenosis. After 18 months to 24 months of follow-up, attempt was made to remove the T-tube in 9 patients but failed in 4 patients. The failure was due to collapse of the airway after the T-tube was removed. Conclusion: T-tube placement is a safe and reliable treatment for benign complex subglottic tracheal stenosis with high efficiency and manageable complications.

Associations between condylar fractures and external auditory canal fracture: A 7-year retrospective study

The study aimed to investigate whether the incidence rate of external auditory canal (EAC) fracture varies among different clinical types of condylar fracture. A retrospective cohort study was conducted in single hospital of China. Eligible patients diagnosed with mandibular condylar fractures were retrospectively reviewed. Among all patients with condylar fractures (318 cases and 437 sides), 45 cases and 59 sides (59/437 sides, 13.5%) were found with EAC fracture, including 17(17/38, 44.7%) sides of sagittal fracture of condyle (Type I), 21(21/59, 35.6%) sides of intracapsular condylar fracture (Type II), 8 (8/306, 2.6%) sides of condylar neck fracture (Type III), and 6 (6/34, 17.7%) sides of condylar base fracture (Type IV). Type III condylar fracture had a significant lower rate of EAC fracture than all other three types (all p<0.001). Type I condylar fracture had a higher rate of EAC fracture compared to Type IV (p=0.014). The incidence rates of EAC fracture in combined Type I+Type II group (38/97, 39.2%) was significantly higher than Type III (8/306,2.6%, p<0.001) and Type IV (6/34,17.7%, p=0.002). A total of 35 sides (27 patients) with combined fractures were followed up for 6 months after treatment, among whom 11 sides (7 patients) were operated for both fractures simultaneously. Neither EAC stenosis nor hearing loss was observed. Meanwhile, for 24 non-operated ears from 20 patients, all EACs showed different degrees of stenosis. In conclusion, oral and maxillofacial surgeons should pay more attention to EAC fracture combined with condylar fracture, especially for patients diagnosed with condylar head fracture. Maxillofacial fractures should be accompanied by early treatment of EAC fractures, in order to prevent EAC stenosis, hearing loss, and other complications.

Effectiveness of Propionyl-L-Carnitine Supplementation on Exercise Performance in Intermittent Claudication: A Systematic Review.

Lower extremity peripheral artery disease (PAD) affects 8.5 million people in the United States and more than 200 million worldwide. The most significant risk factors for PAD are hyperlipidemia, hypertension, diabetes mellitus, chronic kidney disease, and smoking. Intermittent claudication (IC) is the predominant symptom of PAD, but only about 10% of patients with PAD experience IC and are associated with reduced exercise capacity. The pathophysiology of IC is characterized by different degrees of stenosis and obstruction, with a progressive reduction in distal perfusion pressure and blood flow. Supervised exercise therapy is recommended as the initial therapy for IC, but the recommendations for medical treatment of IC vary significantly. Propionyl L-carnitine is an acyl derivative of levocarnitine (L-carnitine) and is indicated for patients with the peripheral arterial occlusive disease. It corrects secondary muscle carnitine deficiency in patients with PAD, significantly improving the walking capacity; its levels increase in serum and muscle. Thus, it is suggested to enhance blood flow and oxygen supply to the muscle tissue via improved endothelial function, thereby reducing hypoxia-induced cellular and biochemical disruptions.

Serum glial fibrillary acidic protein and S100 calcium-binding protein B correlates cerebral vessel reactivity following carotid artery stenting

Using detection markers in serum has the advantages of simplicity, repeatability and the capability. This study combined the use of serum glial fibrillary acidic protein (GFAP) and S100B protein (S100B) with imaging tools to confirm the role of serum biomarkers in evaluating the cerebral vessel reactivity after carotid artery stenting (CAS). After CAS, the serum concentrations of GFAP and S100B increased to the peak at 24 h after operation, and then gradually decreased. The mean flow velocity (MFV) (pre-operation, post-operation, 30 days follow-up: 47.65 ± 17.24 cm/s, 62.37 ± 18.25 cm/s, 70.29 ± 16.89 cm/s; P < 0.05) and pulsatility index (PI) (pre-operation, post-operation, 30 days follow-up: 0.78 ± 0.21, 0.98 ± 0.19, 1.02 ± 0.20; P < 0.05) increased significantly in the ipsilateral middle cerebral artery after CAS. At the 30-day follow-up, the cerebrovascular reserve (CVR) (post-operation, 30 days follow-up: 27.47 ± 12.13 cm/s, 31.92 ± 10.94 cm/s; P < 0.05) improved significantly. In patients with different degrees of stenosis, the more severe the stenosis in the carotid artery, the more obvious the improvement of CVR at the 30 days of follow-up (CVR changes: 11.08 ± 7.95 cm/s, Kendall’s tau-b = 0.645, P < 0.001). And the serum concentrations of GFAP (r = − 0.629, P < 0.0001) and S100B (r = − 0.604, P < 0.0001) correlated negatively with CVR at 30 days after CAS. Therefore, we recommend using the biomarkers GFAP and S100B associated with imaging tools such as transcranial Doppler (TCD) and Magnetic resonance imaging (MRI) to evaluate the cerebral vessel reactivity following CAS.

Digital Subtraction Angiography Contrast Material Transport as a Direct Assessment for Blood Perfusion of Middle Cerebral Artery Stenosis.

Digital subtraction angiography (DSA) is a fluoroscopic technique used extensively in interventional radiology for visualizing blood vessels. It has also been used to evaluate blood perfusion. However, the perfusion obtained in previous techniques was extracted from signal intensity rather than by the transport of contrast material (CM) through blood flow. The main aim of this study is to evaluate the morphological effects on the hemodynamics and the CM concentration in the middle cerebral artery (MCA) stenosis. We proposed a quantitative parameter, i.e., contrast material remaining time (CMRT), to describe the variation in the transport of CM over time. Computational fluid dynamics simulations were performed on both reconstructive synthetic and patient-derived models. In the synthetic models, we evaluated the variation of flow patterns and the transport of CM with different degrees of stenosis and the location of the lesion. It was found that an increase in the degree of stenosis (from 30 to 80%) resulted in a significant increase in CMRT at the anterior cerebral artery (ACA) outlet (p = 0.0238) and a significant decrease in CMRT at the MCA outlet (p = 0.012). The patient-derived models were reconstructed from the pre- and post-interventional DSA images of a patient with MCA stenosis. Both blood flow velocity and CMRT increased at the ACA outlet but decreased at the MCA outlet. The perfusion analysis demonstrated that the perfusion function was improved after interventional surgery. In conclusion, changes in stenotic degree at MCA may lead to apparent differences in the hemodynamic distribution and the transport of CM. CMRT could be a quantitative indicator to evaluate the changes in blood perfusion after the intervention for MCA stenosis.

The impact of hemodynamic factors in a coronary main artery to detect the atherosclerotic severity: Single and multiple sequential stenosis cases

A conventional invasive catheterization procedure is currently used to detect atherosclerotic severity in coronary arteries. However, it is still challenging to measure multiple consecutive stenoses (MCS) in coronary main arteries, a severe condition, by using the invasive method. In this paper, we report important hemodynamic properties such as wall shear stress (WSS) and velocity magnitude (VM) across different luminal areas of coronary stenosis in patient-based right coronary artery models of MCS using pulsatile heart flow simulations. The hemodynamic factors in coronary blood flow simulations of different degrees of stenosis indicated a relationship between the proximal moderate stenosis and distal severe stenosis models. The results show the physical effects of different hemodynamic factors including VM, mean arterial pressure difference, WSS, and virtual fractional flow reserve (vFFR), which allow for predicting the physiological computation in the MCS artery severity conditions. This study identifies the fundamental physics of coronary plaque with MCS and indicates the impact of these factors on vFFR measurements. These findings provide insights into and improvement of the pathophysiological assessment of MCS. The results reveal hemodynamic properties, which can be used to diagnose coronary irregularities using a visualization method.

Frequency of Efficient Circulating Follicular Helper T Cells Correlates with Dyslipidemia and WBC Count in Atherosclerosis.

Background:The significance of cTfh cells and their subsets in atherosclerosis is not well understood. We measured the frequency of cTfh subsets in patients with different degrees of stenosis using flow-cytometry. Methods:Participants included high (≥50%; n = 12) and low (<50%; n = 12) stenosis groups, as well as healthy controls (n = 6). Results: The frequency of CCR7loPD-1hiefficient-cTfh was significantly higher in patients with high stenosis compared to healthy controls (p = 0.003) and correlated with LDL (p = 0.043), cholesterol (p = 0.043), triglyceride (p = 0.019), neutrophil count (p = 0.032), platelet count (p = 0.024), NLR (p = 0.046), and PLR (p = 0.025) in high stenosis group. The frequency of CCR7hiPD-1lo quiescent-cTfh was higher in healthy controls compared to the high-stenosis group (p = 0.001) and positively correlated with HDL (p = 0.046). The frequency of efficient-cTfh cells was correlated with platelet count (p = 0.043), NLR (p = 0.036), and PLR (p P = 0.035) in low-stenosis group, while that of quiescent-cTfh cells was negatively correlated with LDL (p = 0.034), cholesterol (p = 0.047), platelet count (p = 0.032), and PLR (p = 0.041). Conclusion:High percentages of cTfh and efficient-cTfh cells in patients with advanced atherosclerosis and their correlation with dyslipidemia and WBC counts suggests an ongoing cTfh subset deviation, towards efficient phenotype in the milieu of inflammation and altered lipid profile. Efficient cTfh cells have an effector phenotype and could in turn contribute to atherosclerosis progression.

Partial recovery of senescence in circulating follicular helper T cells after Dasatinib treatment

Cellular senescence is an irreversible arrest of cell proliferation triggered by different stimuli, including DNA damage, telomere shortening and oncogenic stress. Senescent cells, by releasing the senescence-associated-secretory-phenotype (SASP), contribute to various diseases pathogenesis. Human atherosclerotic plaque contains cells with multiple markers of senescence that associate with disease severity. We characterized the frequency of senescent cTfh cells and genes expressions before and after treatment with Dasatinib in patients with different degrees of stenosis. Twelve high (≥50%), and twelve low (<50%) stenosis patients and six healthy controls were enrolled. The percentage of senescent CD3+CD4+CXCR5+CD153+CD57+ cells was significantly decreased in Dasatinib treated cells from individuals with low and high stenosis (P = 0.0007 and P = 0.0002, respectively). However, the frequency of total lymphocytes, CD3+ and CD4+ T cells were not significantly different between the groups before and after treatment. The expression levels of P53 (P = 0.0003 and P = 0.0001), P16 (P = 0.0005 and P = 0.0002), p21 (P = 0.0002 and P < 0.0001), SENEX (P = 0.0005 and P < 0.0001) and BCL-2 (P = 0.0005 and P = 0.0002) were decreased in PBMCs of low and high stenosis groups after treatment with Dasatinib, respectively. The percentage of senescent cTfh cells positively correlated with cholesterol (P = 0.034; r = 0.671), C-reactive protein (CRP) (P = 0.029; r = 0.707), Erythrocyte sedimentation rate (ESR) levels (P = 0.030; r = 0.598) and neutrophil counts (P = 0.021; r = 0.799) in patients with high stenosis. The decreased frequency of senescent cTfh cells and the expression levels of senescence genes after Dasatinib treatment in patients with atherosclerosis suggest a role for Dasatinib in partial clearance or rejuvenation of senescent cTfh cells, which may decrease inflammatory mediators and attenuate disease progression.

Near real-time magnetic particle imaging for visual assessment of vascular stenosis in a phantom model.

This study aimed to investigate the potential of magnetic particle imaging (MPI) to quantify artificial stenoses in vessel phantoms in near real-time. Custom-made stenosis phantoms with different degrees of stenosis (0%, 25%, 50%, 75%, and 100%; length 40mm, inner diameter 8mm, Polyoxymethylene) were filled with diluted Ferucarbotran (superparamagnetic iron-oxide nanoparticle (SPION) tracer agent, 500mmol (Fe)/l). A traveling wave MPI scanner (spatial resolution~2mm, gradient strength~1.5T/m, field of view: 65mm length and 29mm diameter, frequencies f1=1050Hz and f2=12150Hz) was used to acquire images of the phantoms (200ms total acquisition time per image, 10 averages). Standardized grey scaling was used for comparability. All measured stenoses (n=80) were graded manually using a dedicated software tool. MPI allowed for accurate visualization of stenoses at a frame rate of 5frames per second. Less severe stenoses were detected more precisely than higher-grade stenoses and came with smaller standard deviations. In particular, the 0%, 25%, 50%, 75%, and 100% stenosis phantom were measured as 3.7±2.7% (mean±standarddeviation), 18.6±1.8%, 52.8±3.7%, 77.8±14.8% and 100±0%. Geometrical distortions occurred around the center of the high-grade stenosis and led to higher standard deviations compared to lower grade stenoses. In the frame of this study the MPI signal depended linearly on the SPION concentration down to 0.05mmol (Fe)/l. Near real-time MPI accurately visualized and quantified different stenosis grades in vascular phantoms.

Numerical study of hemodynamics in a complete coronary bypass with venous and arterial grafts and different degrees of stenosis

Cardiovascular diseases are among the leading causes of death in the world. The coronary blockage is one of most common types of these diseases that in the majority of cases has been treated by bypass surgery. In the bypass surgery, a graft is implemented to alter the blocked coronary and allow the blood supply process. The hemodynamic characteristics of the bypass strongly depend on the geometry and mechanical properties of the graft. In the present study, the fluid-structure interaction (FSI) analysis is conducted to investigate the bypass performance for a thoracic artery as well as a saphenous vein graft. Blood flow introduces a pressure on the walls of the graft which behaves as a hyperelastic material. A complete coronary bypass with stenosis degrees of 70% and 100% is modeled. To consider the nonlinear stress-strain behavior of the grafts, a five parameter Mooney-Rivlin hyperplastic model is implemented for the structural analysis and blood is assumed to behave as a Newtonian fluid. The simulations are performed for a structured grid to solve the governing equations using finite element method (FEM). The results show that wall shear stress (WSS) for saphenous vein is larger than that of thoracic artery while the total deformation of the thoracic artery is larger compared to the saphenous vein. Also, for the venous grafts or lower stenosis degree, the oscillatory shear index (OSI) is higher at both left and right anastomoses meaning that venous grafts as well as lower degree of stenosis are more critical in terms of restenosis.

Analytical Study of Non-Newtonian Reiner–Rivlin Model for Blood flow through Tapered Stenotic Artery

Stenosis, the abnormal narrowing of artery, significantly affects dynamics of blood flow due to increasing resistance to flow of blood. Velocity of blood flow, arterial pressure distribution, wall shear stress and resistance impedance factors are altered at different degree of stenosis. Prior knowledge of flow parameters such as velocity, flow rate, pressure drop in diseased artery is acknowledged to be crucial for preventive and curative medical intervention. The present paper develops the solution of Navier–Stokes equations for conservation of mass and momentum for axis-symmetric steady state case considering constitutive relation for Reiner–Rivlin fluid. Reiner–Rivlin constitutive relation renders the conservation equations non-linear partial differential equations. Few semi-analytical and numerical solutions are found to be reported in literature but no analytical solution. This has motivated the present research to obtain a closed-form solution considering Reiner–Rivlin constitutive relation. Solution yields an expression for axial velocity, which is utilized to obtain pressure gradient, resistance impedance and wall shear stress by considering volumetric flow rate as initial condition. The effect of viscosity, cross viscosity, flow rate, taper angle of artery and degree of stenosis on axial velocity, resistance impedance and wall shear stress are studied.

Abstract 17162: Prediction of Functional Severity of Coronary Bifurcation Lesions by Means of Angiographically-Derived Score

Background: There is uncertainty about relation between clinical and angiographic characteristics and functional significance of bifurcation stenosis. Methods: We analysed patients from FIESTA registry (ClinicalTrials.gov:NCT01724957). Subjects (&gt;18 years) with stable angina, bifurcation lesions with diameter ≥2.5mm and ≤4.5 mm, SB diameter≥2.0 mm were included. We excluded patients with ST-segment elevation myocardial infarction, left main disease, hemodynamic instability. Provisional stenting was the default strategy in all patients. Fractional flow reserve(FFR) was performed using the PrimeWire or PrimeWire Prestige(Volcano Corp., USA). Bifurcation lesion with FFR above 0.80 were deferred from PCI. Results: A total of 171 patients, mean age 67±10 years, 66% males were included in the analysis. Of them 78(46%) had functionally significant bifurcation lesion (FSL) versus 93(54%) with non-significant lesion (nFSL). There were no differences (FSLvs.nFSL) in baseline characteristics: dyslipidemia(88%vs96%), diabetes(44%vs.32%), smoking (52%vs40%), past MI (24%vs15%), previous PCI(54%vs49%), atrial fibrillation (17%vs29%), peripheral artery disease (10%vs9%), renal failure(29%vs31%) –all p&gt;0.05. On logistic-regression analysis independent predictors of functional significance were: SYNTAX score≥11 (OR=5.523,CI:1.666-18.311,p=.005), lesion length≥25mm (OR=21.737,CI:4.963-95.202,p&lt;.001),MV%DS≥55%(OR=9.535,CI:2.508-34.883,p=.001) and MB%DS≥65% (OR=12.927,CI:3.015-55.418,p=.001). We created score for prediction of functional significance of bifurcation lesion with the following parameters: SYNTAX ≥11 gives 1 point, SB BARI≥12%- 1 point, MV%DS ≥55%- 1.5 point, MB%DS≥65%- 2 points, lesion length ≥25 mm – 3 points. The overall performance of the score was excellent with AUC=.960, p&lt;.001. With a cut-off value ≥4.5 points it has sensitivity of 90%, specificity 91%, accuracy 90%, p&lt;.001. Conclusion: Different degree of stenosis in proximal main vessel and distal side branch, lesion length, SB myocardium territory and SYNTAX score are significant predictors of functional severity of bifurcation lesion. A score based on those parameters was developed with excellent discriminatory ability.

Functional subsets of circulating follicular helper T cells in patients with atherosclerosis.

Frequencies of circulating T follicular helper (cTfh) functional subsets vary in autoimmune diseases. We evaluated the frequencies and clinical relevance of functional subsets of cTfhs in patients with different degrees of stenosis. Blood samples were collected from high (≥50%) (n = 12) and low (<50%) stenosis (n = 12) groups and healthy controls (n = 6). Three subsets of cTfh cells including cTfh1 (CXCR3+CCR6‐), cTfh2 (CXCR3‐CCX6‐), and cTfh17 (CXCR3‐CCR6+) were detected by flow cytometry. The frequency of cTfh1 cells was higher in control (p = .0006) and low‐stenosis groups (p = .005) compared to high‐stenosis group. The percentages of cTfh2 and cTfh17 cells were increased in high‐stenosis compared to low‐stenosis (p = .002 and p = .007) and control groups (p = .0004 and p = .0005), respectively. The frequency of cTfh1 cells negatively correlated with cholesterol (p = .040; r = −.44), C‐reactive protein (CRP) (p = .015; r = −.68), erythrocyte sedimentation rate (ESR) (p = .002; r = −.79), neutrophil/lymphocyte ratio (NLR) (p = .028; r = −.67), and cTfh17 (p = .017; r = −.7244) in the high‐stenosis group. The percentages of cTfh2 and cTfh17 cells positively correlated with cholesterol (p = .025; r = .77 and p = .033; r = .71), CRP (p = .030; r = .61 and p = .020; r = .73), ESR (p = .027; r = .69 and p = .029; r = .70), NLR (p = .004; r = .76 and p = .005; r = .74), and with each other (p = .022; r = .7382), respectively, in the high‐stenosis group. The increased frequencies of cTfh2 and cTfh17 subsets and their correlation with laboratory parameters in patients with atherosclerosis may suggest their role in promoting the inflammatory response and atherosclerosis progression.

Correlation between Metabolic Syndrome and Intracranial Versus Extracranial Arteriosclerosis among Chinese Patients with Stroke

We aimed to explore the correlation between metabolic syndrome and intracranial and extra-cranial arteriosclerosis. Overall, 318 over 60-yr-old patients with cerebral infarction or TIA who were examined by digital subtraction angiography (DSA) in our hospital were enrolled in the study. Overall, 192 patients with intracranial and extracranial arteriosclerosis were admitted to the case group (the intracranial and extracranial arteriosclerosis group). Also, 196 patients, suffering from the same condition, were selected from our outpatient clinic and enrolled in the control group. The prevalence of metabolic syndrome was 31.4%. The prevalence of each metabolic syndrome component in the intracranial arteriosclerosis group was higher than those of the extracranial arteriosclerosis and the control groups. The average component values in the intracranial arteriosclerosis group was higher than those observed in other groups. The prevalence rate of metabolic syndrome had no significant difference among different degrees of stenosis for extracranial arteriosclerosis group. There was a remarkable correlation between intracranial arteriosclerosis and metabolic syndrome (P<0.001), while no correlation was detected between extracranial arteriosclerosis and metabolic syndrome (P<0.001). We concluded that metabolic syndrome may increase the prevalence risk of intracranial arteriosclerosis. There was a significant correlation between intracranial arteriosclerosis and metabolic syndrome components including hyperglycemia and hypertension. Also, there was a significant correlation between extracranial arteriosclerosis and metabolic syndrome components including hyperglycemia. We believe that at least three components of metabolic syndrome can obviously increase the risk of intracranial arteriosclerosis.

Clinical value of color Doppler ultrasonography in evaluating the degree of atherosclerotic renal artery stenosis in the elderly by ROC curve analysis

Objective To evaluate the clinical value of color Doppler ultrasonography (CDFI) in evaluating the degree of atherosclerotic renal artery stenosis (ARAS) in the elderly by using ROC curve analysis. Methods From March 2015 to September 2018, 117 patients with ARAS admitted to Anji Branch of the First Affiliated Hospital of Medical College of Zhejiang University were selected.All patients underwent color Doppler ultrasonography and renal artery angiography.Renal artery angiography was used as the gold standard.The diagnostic value of color Doppler ultrasonography for ARAS was analyzed.The changes of color Doppler ultrasonography indicators of renal artery in different degrees of stenosis were compared.The ROC curve was used to analyze the value of color Doppler ultrasound in evaluating the degree of atherosclerotic renal artery stenosis in the elderly. Results Using renal arteriography as the gold standard, the sensitivity of color ultrasonography for ARAS was 82.17% (129/157), and the specificity of diagnosis was 80.52% (62/77). The PSV [(227.59±34.28)cm/s] and EDV [(57.39±6.48)cm/s] in the severe stenosis group were higher than those in the moderate stenosis group [(183.84±41.05) cm/s and (50.29±5.22)cm/s] (t=6.269, 6.506, all P<0.05) and the mild stenosis group [(128.47±52.35)cm/s and (37.52±7.15)cm/s] (t=10.517, 12.813, all P<0.05) and the non-stenosis group [(86.49±28.94)cm/s and (26.48±5.02)cm/s] (t=18.598, 21.971, all P<0.05). The RI in the severe stenosis group[(0.41±0.07)] was lower than that in the moderate stenosis group [(0.47±0.06)] (t=4.966, P<0.05) and the mild stenosis group [(0.52±0.07)] (t=8.496, P<0.05) and the no stenosis group [(0.70±0.11)] (t=17.101, P<0.05). The ROC curve was used to analyze the diagnostic value of color ultrasound parameters for moderate and severe stenosis.The area under the diagnostic curve of PSV, EDV and RI for moderate and severe stenosis was 0.869, 0.932 and 0.937, respectively. Conclusion CDFI plays an important role in the early diagnosis and clinical screening of elderly patients with ARAS.It is helpful to judge the degree of renal artery stenosis and evaluate the condition of the patients.It is non-invasive, simple and inexpensive, and worthy of clinical application. Key words: Ultrasonography, doppler, color; ROC curve; Atherosclerotic renal artery stenosis; Blood flow velocity; End-diastolic flow velocity; Peak velocity ratio; Resistance index; Aged