Impact of coronary tortuosity on coronary blood supply: a patient-specific study

Design of experiment approach to identify the dominant geometrical feature of left coronary artery influencing atherosclerosis

Background and Objective. Coronary artery geometry heavily influences local hemodynamics, potentially leading to atherosclerosis. Consequently, the unique geometrical configuration of an individual by birth can be associated with future risk of atherosclerosis. Although current researches focus on exploring the relationship between local hemodynamics and coronary artery geometry, this study aims to identify the order of influence of the geometrical features through systematic experiments, which can reveal the dominant geometrical feature for future risk assessment.Methods. According to Taguchi's method of design of experiment (DoE), the left main stem (LMS) length (lLMS), curvature (kLMS), diameter (dLMS) and the bifurcation angle between left anterior descending (LAD) and left circumflex (LCx) artery (αLAD-LCx) of two reconstructed patient-specific left coronary arteries (LCA) were varied in three levels to create L9 orthogonal array. Computational fluid dynamic (CFD) simulations with physiological boundary conditions were performed on the resulting eighteen LCA models. Average helicity intensity (h2) and relative atheroprone area (RAA) of near-wall hemodynamic descriptors were analyzed.Results. The proximal LAD (LADproximal) was identified to be the most atheroprone region of the left coronary artery due to higherh2,large RAA of time averaged wall shear stress (TAWSS < 0.4 Pa), oscillatory shear index (OSI ∼ 0.5) and relative residence time (RRT > 4.17 Pa-1). In both patient-specific cases, based onh2and TAWSS,dlmsis the dominant geometric parameter while based on OSI and RRT,αLAD-LCxis the dominant one influencing hemodynamic condition in proximal LAD (p< 0.05). Based on RRT, the rank of the geometrical factors is:αLAD-LCx>dLMS>lLMS>kLMS, indicating thatαLAD-LCxis the most dominant geometrical factor affecting hemodynamics at proximal LAD which may influence atherosclerosis.Conclusion. The proposed identification of the rank of geometrical features of LCA and the dominant feature may assist clinicians in predicting the possibility of atherosclerosis, of an individual, long before it will occur. This study can further be translated to be used to rank the influence of several arterial geometrical features at different arterial locations to explore detailed relationships between the arterial geometrical features and local hemodynamics.

Ultra-Widefield Imaging of the Retinal Macrovasculature in Parkinson Disease Versus Controls With Normal Cognition Using Alpha-Shapes Analysis

Purpose

To investigate retinal vascular characteristics using ultra-widefield (UWF) scanning laser ophthalmoscopy in Parkinson disease (PD).

Methods

Individuals with an expert-confirmed clinical diagnosis of PD and controls with normal cognition without PD underwent Optos California UWF imaging. Patients with diabetes, uncontrolled hypertension, glaucoma, dementia, other movement disorders, or known retinal or optic nerve pathology were excluded. Images were analyzed using Vasculature Assessment and Measurement Platform for Images of the Retina (VAMPIRE-UWF) software, which describes retinal vessel width gradient and tortuosity, provides vascular network fractal dimensions, and conducts alpha-shape analysis to further characterize vascular morphology (complexity, Opαmin; spread, OpA).

Results

In the PD cohort, 53 eyes of 38 subjects were assessed; in the control cohort, 51 eyes of 33 subjects were assessed. Eyes with PD had more tortuous retinal arteries in the superotemporal quadrant (P = 0.043). In eyes with PD, alpha-shape analysis revealed decreased OpA, indicating less retinal vasculature spread compared to controls (P = 0.032). Opαmin was decreased in PD (P = 0.044), suggesting increased vascular network complexity. No differences were observed in fractal dimension in any region of interest.

Conclusions

This pilot study suggests that retinal vasculature assessment on UWF images using alpha-shape analysis reveals differences in retinal vascular network spread and complexity in PD and may be a more sensitive metric compared to fractal dimension.

Translational Relevance

Retinal vasculature assessment using these novel methods may be useful in understanding ocular manifestations of PD and the development of retinal biomarkers.

Predicting severe proximal left anterior descending coronary artery stenosis using proximal left anterior descending coronary artery tortuosity and the angle between the left main and anterior descending coronary arteries: a retrospective cross-sectional study

Background

Coronary bifurcation angles influence plaque initiation in the coronary artery, and changes in blood flow caused by tortuosity in the coronary arteries can reduce blood pressure distal to the tortuous portion of the coronary artery, leading to myocardial ischemia. We aimed to describe two factors (coronary artery tortuosity and bifurcation angle) as one descriptor for the evaluation of proximal left anterior descending coronary artery (LAD) disease.

Methods

We reviewed the medical records of 133 consecutive patients who underwent computed tomography angiography (CTA) for angina symptoms between November 2019 and January 2020. The patients were divided into two groups according to the presence of significant LAD stenosis on CTA (defined as LAD stenosis >50%). The straight length of the vessel was measured using the central luminal line of the flow path, and, calculated using proprietary algorithms in TeraRecon software. We used three-dimensional volume rendering and two-dimensional axial images to measure the left main coronary artery (LM)-LAD angles.

Results

In the univariate analysis, there were significant differences in the linear distance between the endpoints of the 20 mm actual curve of the LAD (d20), cosine value for LM-LAD angle (cosθ) <0.8, age, presence of hypertension or diabetes, and number of pack years [hazard ratio (HR): 2.70, 8.04, 1.05, 3.70, 2.82, and 1.04; P=0.029, P<0.001, P=0.020, P=0.024, P=0.021, and P=0.002, respectively]. However, in the multivariate analysis, the cosθ multiplied by d20 (d20*cosθ) <15.5, presence of hypertension and number of pack years (HR: 11.36, 4.54, and 1.04; P<0.001, P=0.019, and P=0.003, respectively) were predictors of significant proximal LAD stenosis.

Conclusions

As the tortuosity and LM-LAD angle increased (d20 and cosθ decreased, respectively), the chance of proximal LAD lesions formation increased. d20*cosθ might be useful as a predictor of proximal LAD stenosis.

Coronary Tortuosity as a New Phenotype for Ischemia without Coronary Artery Disease

BACKGROUND

Coronary arteries tend to be more tortuous than other arteries and follow the repeated flexion and relaxation movements that occur during the cardiac cycle. Coronary tortuosity (CorT) leads to changes in coronary flow with a reduction in distal perfusion pressure, which could cause myocardial ischemia.

OBJECTIVE

To assess the association between CorT and myocardial ischemia.

METHODS

Between January 2015 and December 2017, 57 patients with angina and nonobstructive coronary artery disease detected by invasive coronary angiography (ICA) were retrospectively enrolled. Angiographic variables were analyzed to assess the presence and degree of tortuosity and correlated with their respective vascular territories on stress myocardial perfusion imaging (MPI). CorT was defined as coronary arteries with three or more bend angles ≤90°, measured during diastole. Statistical significance was determined at the 5% level.

RESULTS

A total of 17 men and 40 women were enrolled (mean age 58.3 years). CorT was observed in 16 patients (28%) and in 24 of 171 arteries. There was a significant association between CorT and ischemia when analyzed per artery (p<0.0001). The angiographic factor most associated with ischemia was the number of bend angles in an epicardial artery measured at systole (p=0.021).

CONCLUSION

This study showed an association of CorT and myocardial ischemia in patients with unobstructed coronary arteries and angina. An increased number of coronary bend angles measured by angiography during systole was related to ischemia.

Relationship between Coronary Artery Tortuosity and Cardiorespiratory Fitness in Patients without Obstructed Coronaries

OBJECTIVE

This study aimed to analyze the relationship between cardiorespiratory fitness (CRF) and the increasing severity of coronary artery tortuosity (CAT) in patients with non-stenosed coronaries.

METHODS

A total of 396 patients who underwent coronary angiography and cardiopulmonary exercise testing (CPET) between August 2020 and July 2021 were included in this single-center retrospective study after excluding patients with significant coronary artery disease (≥50% stenosis). Patients were divided into two groups: no or mild coronary artery tortuosity (N/M-CAT) and moderate to severe coronary artery tortuosity (M/S-CAT) and laboratory electrocardiographic, echocardiographic, and CPET parameters were compared between two groups.

RESULTS

M/S-CAT was found in 46.9% of the study participants, with 66.7% being women. M/S-CAT was significantly associated with advanced age (P=0.014) and females (P=0.001). Diastolic dysfunction parameters, E velocity (P=0.011), and E/A ratio (P=0.004) also revealed significant differences between the M/S-CAT group and N/M-CAT group. VO₂@peak (1.22±0.39 vs. 1.07±0.39, P<0.01) and VO₂@AT (0.77±0.22 vs. 0.71±0.21, P=0.017) were significantly lower in the M/S-CAT group than in the N/M-CAT group. Multivariate logistic regression analysis identified females (OR=0.448; 95% CI, 0.296-0.676; P=0.000) and E/A ratio (OR=0.307; 95% CI, 0.139-0.680; P=0.004) to be independent risk factors of M/S-CAT and showed no association of CPET parameters to M/S-CAT.

CONCLUSION

The results indicate that increasing severity of CAT is strongly associated with female gender and E/A ratio and is not directly correlated with decreasing CRF. Further research with a larger patient population and a longer follow-up time is required to fully comprehend the impact of CAT on CRF.

A Parametric Study of Flushing Conditions for Improvement of Angioscopy Visibility

During an angioscopy operation, a transparent liquid called dextran is sprayed out from a catheter to flush the blood away from the space between the camera and target. Medical doctors usually inject dextran at a constant flow rate. However, they often cannot obtain clear angioscopy visibility because the flushing out of the blood is insufficient. Good flushing conditions producing clear angioscopy visibility will increase the rate of success of angioscopy operations. This study aimed to determine a way to improve the clarity for angioscopy under different values for the parameters of the injection waveform, endoscope position, and catheter angle. We also determined the effect of a stepwise waveform for injecting the dextran only during systole while synchronizing the waveform to the cardiac cycle. To evaluate the visibility of the blood-vessel walls, we performed a computational fluid dynamics (CFD) simulation and calculated the visible area ratio (VAR), representing the ratio of the visible wall area to the total area of the wall at each point in time. Additionally, the normalized integration of the VAR called the area ratio (ARVAR) represents the ratio of the visible wall area as a function of the dextran injection period. The results demonstrate that the ARVAR with a stepped waveform, bottom endoscope, and three-degree-angle catheter results in the highest visibility, around 25 times larger than that under the control conditions: a constant waveform, a center endoscope, and 0 degrees. This set of conditions can improve angioscopy visibility.

Fractional Flow Reserve: Patient Selection and Perspectives

The aim of this review was to discuss the current practice and patient selection for invasive FFR, new techniques to estimate invasive FFR and future of coronary physiology tests. We elaborate on the indication and application of FFR and on the contraindications and concerns in certain patient populations.

Mathematical modeling of plaque progression and associated microenvironment: How far from predicting the fate of atherosclerosis?

Mathematical modeling contributes to pathophysiological research of atherosclerosis by helping to elucidate mechanisms and by providing quantitative predictions that can be validated. In turn, the complexity of atherosclerosis is well suited to quantitative approaches as it provides challenges and opportunities for new developments of modeling. In this review, we summarize the current 'state of the art' on the mathematical modeling of the effects of biomechanical factors and microenvironmental factors on the plaque progression, and its potential help in prediction of plaque development. We begin with models that describe the biomechanical environment inside and outside the plaque and its influence on its growth and rupture. We then discuss mathematical models that describe the dynamic evolution of plaque microenvironmental factors, such as lipid deposition, inflammation, smooth muscle cells migration and intraplaque hemorrhage, followed by studies on plaque growth and progression using these modelling approaches. Moreover, we present several key questions for future research. Mathematical models can complement experimental and clinical studies, but also challenge current paradigms, redefine our understanding of mechanisms driving plaque vulnerability and propose future potential direction in therapy for cardiovascular disease.

Current progress in clinical, molecular, and genetic aspects of adult fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is a non-atherosclerotic vascular disease that may involve medium-sized muscular arteries throughout the body. The majority of FMD patients are women. Although a variety of genetic, mechanical, and hormonal factors play a role in the pathogenesis of FMD, overall, its cause remains poorly understood. It is probable that the pathogenesis of FMD is linked to a combination of genetic and environmental factors. Extensive studies have correlated the arterial lesions of FMD to histopathological findings of arterial fibrosis, cellular hyperplasia, and distortion of the abnormal architecture of the arterial wall. More recently, the vascular phenotype of lesions associated with FMD has been expanded to include arterial aneurysms, dissections, and tortuosity. However, in the absence of a string of beads or focal stenosis, these lesions do not suffice to establish the diagnosis. While FMD most commonly involves renal and cerebrovascular arteries, involvement of most arteries throughout the body has been reported. Increasing evidence highlights that FMD is a systemic arterial disease and that subclinical alterations can be found in non-affected arterial segments. Recent significant progress in FMD-related research which has led to improved understandings of the disease's clinical manifestations, natural history, epidemiology, and genetics. Ongoing work continues to focus on FMD genetics and proteomics, physiological effects of FMD on cardiovascular structure and function, and novel imaging modalities and blood-based biomarkers that can be used to identify subclinical FMD. It is also hoped that the next decade will bring the development of multi-centred and potentially international clinical trials to provide comparative effectiveness data to inform the optimal management of patients with FMD.

Effect of Material and Population on the Delivery of Nanoparticles to an Atherosclerotic Plaque: A Patient-specific In Silico Study

Coronary artery disease (CAD) is the prevalent reason of mortality all around the world. Targeting CAD, specifically atherosclerosis, with controlled delivery of micro and nanoparticles, as drug carriers, is a very proficient approach. In this work, a patient-specific and realistic model of an atherosclerotic plaque in the left anterior descending (LAD) artery was created by image-processing of CT-scan images and implementing a finite-element mesh. Next, a fluid-solid interaction simulation considering the physiological boundary conditions was conducted. By considering the simulated force fields and particle-particle interactions, the correlation between injected particles at each cardiac cycle and the surface density of adhered particles over the atherosclerotic plaque (SDP) were examined. For large particles (800 and 1000 nm) the amount of SDP on the plaque increased significantly when the number of the injected particles became higher. However, by increasing the number of the injected particles, for the larger particles (800 and 1000 nm) the increase in SDP was about 50% greater than that of the smaller ones (400 and 600 nm). Furthermore, for constant number of particles, depending on their size, different trends in SDP were observed. Subsequently, the distribution and adhesion of metal-based nanoparticles including SiO₂, Fe₃O₄, NiO₂, silver and gold with different properties were simulated. The injection of metal particles with medium density among the considered particles resulted in the highest SDP. Remarkably, the affinity, the geometrical features, and the biophysical factors involved in the adhesion outweighed the effect of difference in the density of particles on the SDP. Finally, the consideration of the lift force in the simulations significantly reduced the SDP and consistently decreased the particle residence time in the studied domain.

Coronary flow reserve and microcirculatory resistance in patients with coronary tortuosity and without atherosclerosis

Objective

Coronary tortuosity may affect epicardial coronary arterial blood flow. This study aimed to investigate the effect of coronary tortuosity on coronary flow reserve and the coronary microcirculation in patients without apparent coronary atherosclerosis.

Methods

Prospective patients (n = 8, 3 men, mean age: 58 ± 6.0 years) with coronary tortuosity and without apparent coronary atherosclerosis were enrolled. Coronary tortuosity was defined by the finding of ≥three bends (defined as a ≥45° change in vessel direction) along the main trunk of the left anterior descending artery or left circumflex artery. Coronary flow reserve and the index of microcirculatory resistance were measured by the thermodilution technique.

Results

A total of eight coronary arteries with coronary tortuosity were analyzed. The mean fractional flow reserve was 0.98 ± 0.007. The mean coronary flow reserve was 1.5 ± 0.3, which is much lower than that in the normal coronary artery as reported in the literature. The mean index of microcirculatory resistance was 26.7 ± 2.3, which is much higher than that in the normal coronary artery.

Conclusions

Coronary tortuosity is associated with decreased coronary flow reserve and an increased index of microcirculatory resistance.

Trial registration: This study is registered at the Chinese Clinical Trial Registry, NCT No: ChiCTR2000033671

Assessment of Myocardial Perfusion by Angiographic Methods in Tortuous Coronary Arteries

The relationship between coronary tortuosity (CorT) and tissue-level myocardial perfusion is not clear. We investigated tissue perfusion in myocardial territories supplied by tortuous coronary arteries. Among patients who had undergone coronary angiography, patients with reported CorT, those with ≥1 coronary artery were included in the study group (100 patients). The control group included patients with normal coronary arteries (100 patients). Thrombolysis In Myocardial Infarction frame count (TFC) and myocardial blush grade (MBG) were calculated for each coronary artery. Mean TFC was significantly higher in tortuous right coronary artery (RCA), left anterior descending (LAD) artery, and circumflex (Cx) artery compared to their non-tortuous counterparts (28.81 ± 6.463 vs 21.94 ± 3.328, P = .009; 43.28 ± 5.698 vs 36.17 ± 3.875, P = .006; 29.35 ± 4.111 vs 23.821 ± 2.639; P < .001, respectively). Mean MBG was also significantly lower in tortuous RCA, LAD, and Cx, compared to their normal counterparts (2.78 ± 0.417 vs 2.98 ± 0.155, P < .001; 2.74 ± 0.483 vs 2.97 ± 0.164, P < .001; 2.92 ± 0.277 vs 2.99 ± 0.110, P < .001, respectively). For each tortuous coronary artery, TFC was similar for every MBG category. Tortuous coronary arteries have higher TFC and lower MBG, suggesting impaired epicardial and microvascular coronary flow, when compared to normal coronary arteries.

Coronary tortuosity is negatively correlated with coronary atherosclerosis

Objective

The impact of coronary tortuosity on coronary atherosclerosis remains unclear. This study was performed to determine to the relationship between coronary tortuosity and the presence of coronary atherosclerosis.

Methods

Tortuosity and the presence of coronary atherosclerosis in the main coronary arteries were evaluated. The coronary artery was divided into non-tortuous and tortuous segments. The incidence of coronary atherosclerosis between the two segments was compared.

Results

The prevalence of coronary atherosclerotic stenosis was significantly lower in the tortuous than non-tortuous segment.

Conclusion

The prevalence of coronary atherosclerotic stenosis is lower in the coronary tortuous than non-tortuous segment, indicating that coronary tortuosity might be considered a protective factor for atherosclerosis.

Two-dimensional speckle-tracking echocardiographic evaluation of the longitudinal deformation of the left ventricular myocardium in patients with severe coronary artery tortuosity

PURPOSE

Coronary artery tortuosity (CAT) is an anatomical condition in which epicardial coronary arteries have abnormal curves or spiral courses. Although correlated with higher rates of positive stress test, its effects on the myocardial function remain to be clearly defined.

METHODS

We included in this cross-sectional study and evaluated with 2D speckle-tracking echocardiography 40 consecutive patients admitted to our hospital for selective coronary angiography which showed severe CAT without significant epicardial coronary artery stenosis, and 40 consecutive subjects matched for age, hypertension, and diabetes in whom selective coronary angiography showed neither CAT nor significant epicardial coronary artery stenosis.

RESULTS

Systolic strain, strain rate, and early and late diastolic strain rates were not significantly different between the 2 groups, even after adjustment for potential confounding variables.

CONCLUSION

The 2D speckle-tracking echocardiography-derived indices of longitudinal deformation of the left ventricular myocardium were not significantly different between the patients with severe CAT and controls.

"Lambda-wave" ST-elevation is associated with severe prognosis in stress (takotsubo) cardiomyopathy

BACKGROUND

Persistent ST-segment elevation in acute coronary syndrome is associated with both short and long-term complications. By contrast, there is limited information about ST-elevation and its evolution during takotsubo (stress) cardiomyopathy (TTC).

AIM

To evaluate whether persistent downsloping ST-elevation in the early stages of TTC might correlate with short and long-term clinical events.

METHODS

One-hundred fifty-eight consecutive subjects with TTC were prospectively enrolled and assessed by electrocardiogram. Patients were classified in two groups according to the presence of downsloping ST-elevation ≥5 mm lasting at least 24 hr ("lambda-wave" ST-elevation group vs. without downsloping ST-elevation) in at least one/two contiguous leads.

RESULTS

Five (3.2%) patients, all female with a mean left ventricular ejection fraction 32 ± 5%, were included in the lambda-wave ST-elevation group. These patients were characterized by a higher prevalence of physical stressor (100% vs. 49%, p = 0.04) and higher admission and peak levels of troponin-I levels during hospitalization. Peak of ST-elevation in the lambda-wave ST-elevation group was reached 6 hr after admission and gradually decreased after 24 hr. In-hospital complications were observed in all the patients presenting lambda ST-elevation (100% vs. 23%, p = 0.03, OR: 29.1, p = 0.04); one patient presented endoventricular thrombosis and two died of cardiogenic shock. At long-term follow-up (mean 443 days), adverse events were observed in 80% of patients with lambda-wave ST-elevation (RR of adverse events at follow-up 32, p < 0.01).

CONCLUSION

Persistent downsloping lambda-wave ST-elevation during the acute phase of stress cardiomyopathy may be associated with a higher risk of adverse events at short and long-term follow-up.

Coronary tortuosity is associated with an elevated high-sensitivity C-reactive protein concentration and increased risk of ischemic stroke in hypertensive patients

Objective

The clinical implication of coronary tortuosity is unclear. The present study was conducted to determine the relationships between coronary tortuosity and the high-sensitivity C-reactive protein (hs-CRP) concentration and between coronary tortuosity and cerebrovascular accident in hypertensive patients without coronary artery disease.

Methods

In total, 236 patients with normal coronary angiography findings were categorized into 3 different groups: control participants (n = 58), who had neither hypertension nor coronary tortuosity; patients with hypertension but no coronary tortuosity (H-NCT group, n = 93); and patients with both hypertension and coronary tortuosity (H-CT group, n = 85). The hs-CRP concentration was measured in every patient, and 168 hypertensive patients were followed up for at least 2 years to check for the development of cerebrovascular accident.

Results

The hs-CRP concentration was significantly higher in the H-CT group than in the control and H-NCT groups (4.33 ± 3.15 vs. 1.52 ± 1.31 and 2.31 ± 2.09 mg/L, respectively). The incidence of lacunar infarction was higher in the H-CT than H-NCT group during the follow-up.

Conclusions

Hypertensive patients with coronary tortuosity have a higher serum hs-CRP level concentration and have a higher incidence of lacunar infarction than hypertensive patients without coronary tortuosity.

Relationship between coronary tortuosity and plateletcrit coronary tortuosity and plateletcrit

Background

Coronary tortuosity (CorT) is a common angiographic finding and may be associated with myocardial ischaemia, even without coronary artery disease. Platelets play a crucial role in inflammatory and thrombotic processes and the physiopathology of cardiovascular disease. Larger platelets are more active enzymatically and have higher thrombotic ability compared to smaller platelets. Plateletcrit (PCT) provides complete information on total platelet mass. We aimed to evaluate the relationship between CorT and PCT in patients with chronic stable angina.

Methods

The medical records of consecutive patients who underwent coronary angiography from January 2013 to January 2016 were retrospectively reviewed for CorT. CorT and clinical, echocardiographic, haematological and biochemical parameters were evaluated. Taking into consideration the inclusion criteria, 106 patients with CorT and 108 with normal coronary angiographies (control group) were included in the study. CorT was defined as three fixed bends during both systole and diastole, with each bend ≥ 45°.

Results

The median PCT, mean platelet volume (MPV), platelet:large-cell ratio (P-LCR), neutrophil:lymphocyte ratio (NLR) and platelet:lymphocyte ratio (PLR) of the CorT group were significantly higher than those of the control group (0.26 ± 0.02 vs 0.2 ± 0.03%, p < 0.001; 10.6 ± 0.14 vs 9.6 ± 0.65 fl, p < 0.001; 29.3 ± 6.7 vs 23.4 ± 5.1, p < 0.001; 2.3 ± 1 vs 1.47 ± 0.48, p < 0.001; 1.28 ± 0.5 vs 0.82 ± 0.23, p < 0.001, respectively). The incidence of diabetes mellitus, hypertension and female gender were significantly higher in the CorT group (18.9 vs 1.9%, p < 0.001, 90.6 vs 50%, p < 0.001, 70.8 vs 44.4%, p < 0.001, respectively). Multivariate logistic regression analysis revealed age, hypertension, diabetes mellitus and plateletcrit were independently associated with CorT.

Conclusion

CorT was associated with increased PCT, MPV, P-LCR, NLR and PLR, even in the absence of coronary artery disease. Age, hypertension, diabetes mellitus and plateletcrit were independently associated with CorT.

1-D blood flow modelling in a running human body

In this paper an attempt was made to simulate blood flow in a mobile human arterial network, specifically, in a running human subject. In order to simulate the effect of motion, a previously published immobile 1-D model was modified by including an inertial force term into the momentum equation. To calculate inertial force, gait analysis was performed at different levels of speed. Our results show that motion has a significant effect on the amplitudes of the blood pressure and flow rate but the average values are not effected significantly.

Tortuosity, Recurrent Segments, and Bridging of the Epicardial Coronary Arteries in Patients With the Takotsubo Syndrome

Myocardial bridging (MB) and a long recurrent wraparound left anterior descending artery (wrap-LAD) are coronary anatomic variants that have been recently suggested to be associated with takotsubo syndrome (TS). Until now, coronary artery tortuosity (CAT) has never been investigated in this setting. Our study sought to evaluate the prevalence of the aforementioned anatomic variants in a large population with TS. In this retrospective angiographic study, 109 patients with TS were compared with 109 age- and gender-matched subjects without coronary artery disease, valve heart disease, or cardiomyopathy. CAT was identified by ≥3 consecutive curvatures ≥90° (criteria 1) or by ≥2 consecutive curvatures ≥180° (criteria 2). Wrap-LAD was defined if any part of the vessel outreached the apex of the left ventricle and MB as the presence of a milking effect or a step-up and step-down phenomenon. An anatomic variant was found in 79 patients with TS (72%) and in 48 controls (44%) (p <0.001). CAT in at least 1 vessel (criteria 1: 49% vs 20%, p <0.001; criteria 2: 38% vs 13%, p <0.001), ≥2 vessels (criteria 2: 14% vs 3%, p = 0.005), and wrap-LAD (41% vs 27%, p = 0.02) were significantly more frequent in patients with TS than in controls. The prevalence of MB (9% vs 5%, p = 0.18) did not differ between groups. In conclusion, CAT and wrap-LAD have higher prevalence in patients with TS than in matched controls. These findings could support the hypothesis that anatomic variants might act as potential pathogenic substrates in TS.

Effects of Vessel Tortuosity on Coronary Hemodynamics: An Idealized and Patient-Specific Computational Study

Although coronary tortuosity can influence the hemodynamics of coronary arteries, the relationship between tortuosity and flow has not been thoroughly investigated partly due to the absence of a widely accepted definition of tortuosity and the lack of patient-specific studies that analyze complete coronary trees. Using a computational approach we investigated the effects of tortuosity on coronary flow parameters including pressure drop, wall shear stress, and helical flow strength as measured by helicity intensity. Our analysis considered idealized and patient-specific geometries. Overall results indicate that perfusion pressure decreases with increased tortuosity, but the patient-specific results show that more tortuous vessels have higher physiological wall shear stress values. Differences between the idealized and patient-specific results reveal that an accurate representation of coronary tortuosity must account for all relevant geometric aspects, including curvature imposed by the heart shape. The patient-specific results exhibit a strong correlation between tortuosity and helicity intensity, and the corresponding helical flow contributes directly to the observed increase in wall shear stress. Therefore, helicity intensity may prove helpful in developing a universal parameter to describe tortuosity and assess its impact on patient health. Our data suggest that increased tortuosity could have a deleterious impact via a reduction in coronary perfusion pressure, but the attendant increase in wall shear stress could afford protection against atherosclerosis.

SHEAR-INDUCED PLATELET ACTIVATION IN TORTUOUS CORONARY ARTERY: A NUMERICAL STUDY

High fluid shear stresses (FSSs) were observed in tortuous coronary arteries, especially during the strenuous exercise condition. Whether these high FSSs would enhance the shear-induced platelet activation is still unknown. A computational fluid dynamics (CFD) study was conducted to evaluate the impact of coronary tortuosity (CT) on the shear-induced platelet activation during various conditions. A patient-specific left anterior descending (LAD) coronary artery model (CT model) and the corresponding non tortuous model (nCT model) were reconstructed to perform three-dimensional CFD analysis. Lagrangian particle analysis was performed to further obtain the platelet activation state (PAS) of the platelet-like particles. No significant difference was observed between CT and nCT models on the PAS values reached by the platelet-like particles at all simulated conditions. PAS values for particles within both CT and nCT models were decreased during exercise conditions, as compared to those during the rest condition. These results confirmed that CT could not enhance the platelet activation even with extreme high FSSs existing at bend sections during the strenuous exercise condition, and the results also implied that high FSSs might not be the critical factor leading to the platelet activation during the strenuous exercise for persons without the coronary obstructive.

Association between blood lipid levels and personality traits in young Korean women

Abnormal lipid levels are important etiological factors associated with the development of atherosclerosis and with increased cardiovascular morbidity and mortality. Lipid levels are also influenced by lifestyle and behavioral factors, which suggests that personality traits might be related to abnormal lipid profiles. Studies on personality traits and lipid levels are relatively scarce in Korea. Therefore, the objective of this study was to examine the association between lipid levels and personality traits in young Korean women. A total of 1,701 young Korean women [mean age  = 24.9±4.6 years (range 17-39)] who volunteered for personality trait evaluation were recruited for this study. Lipid levels, including total cholesterol, high density lipoprotein (HDL) cholesterol, and triglyceride, were measured in all subjects after an overnight fast, and a low density lipoprotein (LDL) cholesterol level was calculated. The study population was divided into abnormal and normal lipid level groups according to the clinical criteria. Personality traits were measured using the Revised NEO Personality Inventory for the Five-Factor Model of personality. High neuroticism was associated with low HDL cholesterol levels. Low extraversion and openness were associated with high levels of triglyceride. At the facet level, the association between personality and lipid levels were generally consistent. Angry hostility, self-consciousness, vulnerability to stress, activity, and straightforwardness were associated with HDL cholesterol levels. Activity, positive emotion, aesthetics, actions, and deliberation were associated with triglyceride. When applying clinical criteria, conscientiousness was less likely to have abnormal total cholesterol levels. Our results showed that the women with the low HDL cholesterol levels are like to be more neurotic and the hyperglycemic women are prone to lower extraversion and openness in Korea. Understanding the associations between blood lipid levels and personality traits may have a beneficial effect for the managing of dyslipidemia.