Arterial System Research Articles

Reappraisal of arterial anatomy of thumb.

The nomenclature of arteries supplying the thumb and its sources arteries differs between the studies. This makes difficulty in understanding the irrigation pattern to the thumb. The main purpose of this study was to identify the proper digital arteries supplying the thumb on its radial and ulnar side from both the palmar and dorsal aspect. Also this study aimed to trace its source and classify with proper definition with the review of blood supply to thumb. Dissection was carried out in 55 hands form 28 freshly embalmed adult human cadavers of both genders. The proper digital arteries to the thumb and its source arteries were carefully traced and defined. Thumb receives its dominant blood supply mostly from its palmar side. The ulnar palmar digital artery was seen in all the dissected hand (100.0%) whereas; the radial palmar digital artery was present in 53 hands (96.4%). The radial dorsal digital artery and ulnar dorsal digital artery were observed in only 10.0% and 7.3%. The most common source of both the palmar digital arteries to thumb was from first palmar metacarpal artery (FPMA). In majority of the hands, in addition to the radial or ulnar palmar digital arteries from the FPMA, there were also additional palmar digital arteries arising from the superficial palmar arterial system. The universal naming of the proper digital arteries to the thumb as well as its source arteries is mandatory for the proper understanding of normal as well as variant arterial anatomy of thumb.

Endovascular Management of Spontaneous Indirect Carotid- Cavernous Fistula

Carotid cavernous fistulas (CCF) are abnormal communications inducing shunting of blood between the carotid arterial system and the cavernous sinus (CS), resulting in flow reversal in the veins draining through the CS.1 CCFs can be classified as spontaneous or traumatic according to the etiology and direct or indirect (dural) according to the anatomical features2. The authors have dealt a case of a spontaneous indirect Carotid-Cavernous Fistula in a young male of 30 on the right side. The patient presented with headache and bulging of right eye. On examination there was pulsatile proptosis on the right side with conjunctival congestion. CT angiography revealed CCF on the right side with dilated, tortuous right ophthalmic and common facial vein. DSA revealed indirect Carotid-Cavernous Fistula fed by right middle meningeal artery (MMA), accessory meningeal artery and branch of right ophthalmic artery(OA) drained by right ophthalmic vein with abnormal communication via right common facial vein. Patient underwent transarterial embolization with ONYXR . DSA revealed total obliteration of fistula. Headache subsided and proptosis reduced immediately after embolization on procedure table with intact neurology. Almost two months down the follow up revealed complete recovery of proptosis and conjunctival congestion with no further headache. Bang. J Neurosurgery 2022; 11(2): 128-133

Successful Endovascular Management of a Massive Hemoptysis due to a Rare Oncological Giant Pulmonary Artery Pseudoaneurysm

Massive hemoptysis represents a distressing and life-threatening condition: 95% of cases originate from the bronchial artery system, with pulmonary arteries accounting for 6%–11% of cases. The most common etiology of hemoptysis from the pulmonary artery system is represented by pulmonary artery pseudoaneurysms (PAPs). PAPs are defined as the focal dilation of a pulmonary artery branch, involving only the adventice, with a higher risk of rupture than a true aneurysm. It constitutes a rare finding, often underdiagnosed by radiologists. However, PAPs can be life-threatening if undiagnosed due to a high mortality rate (50%). They frequently occur in patients affected by erosive inflammatory processes and necrotising infections of the lung or heart, but other etiological factors include trauma, vasculitis, neoplasia, pulmonary hypertension and Hughes–Stovin Syndrome. PAPs due to oncologic etiologies are rare. Among oncologic etiologies, the most frequent are represented by primary lung cancer rather than metastases. Today, CT angiography represents the imaging modality of choice; not only to establish diagnosis, but if performed with an appropriate timing of intravenous contrast, it also helps to plan therapy with an endovascular approach. In fact, endovascular treatment is the preferred therapeutic approach in managing hemoptysis due to PAPs, since a surgical approach is associated with a high risk of morbidity and mortality, especially in patients who are poor surgical candidates. In this article we report the case of massive hemoptysis due to an unusual giant PAP of the posterior lower branch of the right pulmonary artery, in a patient affected by pulmonary colliquated and confluent metastases, successfully treated by endovascular embolisation.

Change in instantaneous wave-free ratio in the donor artery in multivessel coronary disease: a case report

Patients with multivessel coronary artery disease require an individual approach when choosing tactics for myocardial revascularization. In some cases, additional methods for assessing the stenosis significance should be used, such as measuring the fractional or instantaneous wave-free ratio, in order to decide on the most optimal and safe management of a patient. The article presents a case report of a change in the functional significance of stenosis of the left anterior descending artery (donor artery) after endovascular treatment in the right coronary and circumflex artery systems in a patient with three-vessel coronary disease and diabetes.

Are the Variations of the Vascular System in Neurology Underestimated ?

Abstract The spinal cord issues affect dogs and cats very commonly. The right diagnostics, therapy, and patient’s managements are challenging for almost all veterinarians. There exist many vascular anomalies such as: the vertebral arteries ectasia, hypoplasia and subclavian steal syndrome. These anomalies affect the patient’s neurological status directly. The modern diagnostic approaches (Computed Tomography [CT], and Magnetic Resonance Imaging [MRI]) help with the diagnosis of the vascular abnormalities of the spinal cord and various other vascular anomalies. The cervical part of the spinal cord is supplied with the spinal branches from the vertebral arteries. The vertebral arteries as the first branches arise separately from the subclavian artery and they exit the thoracic aperture and enter into the transverse foramen of the sixth cervical vertebra. The arterial system of dogs was studied in 14 dogs (carcasses), the average age of which was 7 years. The carcasses were divided into two groups: 11 dogs were studied by the corrosion casting method (Duracryl Plus) and 3 dogs were studied by contrast radiography (Urografin 76 %). We confirmed the standard origin and course of the left vertebral for all but one case. The right vertebral artery originated as an independent branch in 57.14 % of the cases; in the rest of them, we reported on the variability in origin and formation of inconstant branches. The formation of anastomoses was reported also. Our work contributed new information about the thoracic and cervical arterial system in dogs.

S-17-01 Dietary and inhalation exposure to nano- and microplastic particles: potential implications for human health

The ascending branch of the aorta is one of the most stressed organ of the arterial system. We aim to design a biomechanical model for analysing the aorta dynamics under a shock. The model includes the aorta layers and the influence of the blood pressure. We undertake a three-dimensional modal analysis of the coupled aorta–blood system. We determine in the present work the coupled natural frequencies and the modes shapes of the system of the aorta and blood. Three models are presented in this study: three-layers model, two-layers model and one layer model. For the analytical solving a potential technique is used to obtain a general solution for an aorta domain. The finite element model is then validated by these original analytical solutions. The results from the proposed method are in good agreement with numerical solutions.

Crisis, Feminism, and Existentialism: Re-reading El-Saadawi’s Memoirs of a Woman Doctor in COVID -19 times

In her Memoirs of a Woman Doctor, Dr. Nawal El-Saadawi, an Egyptian physician, writer and feminist, describes the development of her existential questions as a human being and a doctor throughout her life changes and the interaction with her socio-cultural patriarchal context. Following a crisis in her professional identity, Dr. El-Saadawi questions the meaning of doctoring, the doctor-patient relationship, and life as well as the absurdity of death and alienation. A young woman died while giving birth to her first child, and Dr. El-Saadawi's failure to save the woman's life changed her self-positioning in relation to medicine and the sanctity of science. This experience caused her to sanctify human beings and the humanity of doctors, rather than sanctifying their knowledge only, and created an acute awareness of the link between her body, mind and soul. She writes “The focus of the struggle inside me widened out from masculinity and femininity to embrace humankind as a whole. Human beings appeared to be insignificant creatures in spite of their muscles, their brain cells and the complexity of their arterial and nervous systems. A small microbe, invisible to the naked eye, could be breathed in through the nose and eat away at the cells of the lungs. An unidentifiable virus could strike at random and make the cells of the liver or spleen or any other part of the body multiply at a crazy rate and devour everything around them […] I found my feet taking me in a completely new direction.” (p. 21). In the end, she finds relief for her soul in her love for a musician and attributes music to rescuing her from darkness. Drawing on content-thematic analysis of the memoirs, in this presentation I make an analogy between the crisis that Dr. El-Saadawi experienced, and the potential crises that health care providers (HCPs) faced during their work in the first stages of the COVID-19 pandemic. Through the existential and philosophical questions suggested by Dr. El-Saadawi, in this presentation, I suggest that we look behind the scenes of the ICU and think in-depth about healthcare providers' existential experiences during the COVID-19 outbreak - a global crisis that can be very personal for the HCPs. We will discuss how the crisis and facing death on daily basis could influence healthcare providers' existential and philosophical perceptions, when they are unable to control a virus and save lives.

Features of treatment of chronic brain ischemia in young patients with arterial hypertension

Actuality: Increasing the frequency of hypertension among the young population is a socially significant problem. The insidiousness of hypertension in young people is that it has the character of a disease with few symptoms. Since hypertension plays one of the main roles in the pathogenesis of chronic disorders of cerebral blood circulation, including both arterial and venous systems, the search for pathogenetically determined medicinal approaches to the elimination of cerebrovascular disorders, especially at a young age, continues. The purpose of the study: to study the effectiveness, tolerability and safety of the combination of Flego and Cognitium in young patients with chronic cerebral ischemia (CMI) on the background of hypertension. Methods: clinical-neurological, psychodiagnostic (asthenic state scale (ASS), anxiety scores according to the Spielberger-Hanin scale and Beck depression scale, Montreal scale of cognitive function assessment (MoCA)), ultrasound examination, general scale of clinical impression, statistical. Results: 52 patients (28 men and 24 women) at a young age with AMI on the background of hypertension were examined. The median age of the examined patients was (37.7 ± 4.6) years; among them, 23 patients suffered from hypertension of the 1st century. and 29 patients with hypertension of the second stage. Patients were randomly divided into two groups - the first - 23 (44.2%) patients (received only hypotensive drugs), the second - 29 (55.8%) patients (in addition to the standard hypotensive therapy received a combination of Phlego and Cognitium). Dynamic monitoring of patients after 2 months of treatment did not show significant changes in the distribution structure of objective clinical and neurological symptoms. However, positive dynamics of indicators of cognitive functions and the psychoemotional state of the subjects were observed, as well as a statistically significant decrease in the blood flow rate in the direct sinus at the end of the 2-month course using the combination of Phlego and Cognitium (decreased from 36.27±2.84 cm/s to 25.65±1.47 cm/s.). Conclusions: The introduction of the combination of Phlego and Cognitium into the treatment of young patients with arterial hypertension and chronic brain ischemia had a positive effect on the subjective state, on indicators of asthenia, emotional and cognitive state of the patients. A significant positive effect was noted in the dynamics of venous blood flow indicators (speed of blood flow in the direct sinus). Such treatment was well tolerated by patients, had few side effects and was combined with other drugs

Clinical analysis of the communicating artery between the dorsal and plantar aspects of the foot

Purpose: One of the treatment methods for critical limb ischemia is percutaneous transluminal angioplasty (PTA). In severe cases, however, multiple vessels are blocked, including the main vessels of the lower extremities. This study aimed to determine whether wound healing and symptom relief occurred depending on whether the communicating artery was patent after PTA.Methods: In total, 120 patients (120 lower extremities) who underwent PTA from January 2016 to February 2018 were followed up for 6 months.Results: Out of 87 patients who had wounds, 34 had a patent communicating artery and 53 had a non-patent communicating artery. Out of 34 patients who had wounds but a patent communicating artery, 29 completely healed within 6 months. Among the 53 patients who had wounds and a non-patent communicating artery, 16 totally healed within 6 months, and 37 did not heal within 6 months. In the indirect revascularization group, 18 of 21 patients with complete wound healing within 6 months in the indirect revascularization group had a patent communicating artery.Conclusion: If only indirect revascularization is possible, it is important to ensure the patency of the communicating vessels that link the pedal and plantar arterial systems.

CT Angiographic Study on the Variations of the Hepatic Arteries in the Living Liver Donors of the South Indian Population.

Living liver donor transplantation is the last option for the end stage liver diseases. The variations in the hepatic artery of the liver donor may lead to poor outcome, or may end with major post-operative complications such as hepatic artery thrombosis. To prevent the post-operative complications and to increase the success rate of the liver transplant surgeries, CT evaluation of the hepatic arteries is essential. Thus, the present study was aimed to study the variations of the hepatic arteries in the living liver donors. A total of 200 CT angiograms were collected from the department of Radiology from August 2018 to December 2021, and the evaluation was carried out in the Department of Anatomy, Deccan College of Medical Sciences, Hyderabad. All the CT angiograms were studied for the variations of hepatic arterial system, and the observed variations were noted and the incidence was calculated. The normal anatomy was observed in 62.5% liver donors and 37.55% of liver donors showed variations in hepatic arterial pattern. The incidence of the replaced left hepatic retry, replaced right artery, replaced left along with replaced right hepatic artery was observed as 11.5%, 9.5% and 3% respectively. The incidence of left and right accessory hepatic arteries was 7% and 4% respectively and the replaced right hepatic artery with accessory left hepatic artery was observed in 1.5% cases. The variations observed in the hepatic arterial pattern observed in this study could be helpful to the surgeons, while planning and selecting the suitable liver donors and also may minimise the risk and increase the success rate.Â

This Month in Anesthesiology

This Month in Anesthesiology

Mortality of older persons with and without abnormalities in the physical examination of arterial system

BackgroundAnkle-brachial index (ABI) is a screening tool for peripheral arterial disease (PAD). However, persons with normal ABI may still exhibit abnormalities in the physical examination of arterial system (PHEA).ObjectiveIn older persons from the PolSenior study, we aimed to assess the risk of total mortality associated with abnormalities in PHEA in the context of dichotomised ABI.MethodsWe used data from the PolSenior survey and matched them with mortality information from the Polish Census Bureau. We obtained sociodemographic, medical history, and lifestyle data. The PHEA by a geriatrician included carotid, femoral, popliteal, posterior tibial and the dorsalis pedis arterial pulses, and auscultation of aorta, carotid, femoral, and renal arteries. Ankle-brachial index was tibial to brachial SBP ratio. We plotted the stratified Kaplan–Meier curves and used Cox’s regression to assess the unadjusted and adjusted influence of PHEA result on time to death.ResultsThe mean (standard deviation, SD) age of 852 persons (46.7% women) was 74.7 (10.6) years. In the ABI < 0.9 group, the PHEA was not associated with mortality. However, in the ABI ≥ 0.9 group, both in unadjusted and adjusted (RHR; 95% CI: 1.08; 1.02–1.16, p = 0.01) Cox regression, PHEA greater by 1 score was associated with mortality. Presence of 4 or more PHEA abnormalities was raising the risk in the ABI ≥ 0.9 group to the level associated with ABI < 0.9.ConclusionsIn the older persons with normal ABI, the greater number of abnormalities during physical examination of arteries may be indicative of higher risk of death.

A fluid-structure interaction model accounting arterial vessels as a key part of the blood-flow engine for the analysis of cardiovascular diseases

According to the classical Windkessel model, the heart is the only power source for blood flow, while the arterial system is assumed to be an elastic chamber that acts as a channel and buffer for blood circulation. In this paper we show that in addition to the power provided by the heart for blood circulation, strain energy stored in deformed arterial vessels in vivo can be transformed into mechanical work to propel blood flow. A quantitative relationship between the strain energy increment and functional (systolic, diastolic, mean and pulse blood pressure) and structural (stiffness, diameter and wall thickness) parameters of the aorta is described. In addition, details of blood flow across the aorta remain unclear due to changes in functional and other physiological parameters. Based on the arterial strain energy and fluid-structure interaction theory, the relationship between physiological parameters and blood supply to organs was studied, and a corresponding mathematical model was developed. The findings provided a new understanding about blood-flow circulation, that is, cardiac output allows blood to enter the aorta at an initial rate, and then strain energy stored in the elastic arteries pushes blood toward distal organs and tissues. Organ blood supply is a key factor in cardio-cerebrovascular diseases (CCVD), which are caused by changes in blood supply in combination with multiple physiological parameters. Also, some physiological parameters are affected by changes in blood supply, and vice versa. The model can explain the pathophysiological mechanisms of chronic diseases such as CCVD and hypertension among others, and the results are in good agreement with epidemiological studies of CCVD.

A cadaveric study on variation in branching pattern of common carotid artery

Carotid arterial system are vessels of head and neck region. Comprehensive understanding on its branching configuration is of considerable importance to avoid accidental injury during surgical interventions. Common carotid artery (CCA) usually bifurcates into external carotid artery (ECA) and internal carotid artery (ICA) at level of upper border of thyroid cartilage. Normally ECA lies anteromedial to ICA at its commencement and provides branches, but ICA does not provide any branches in neck. In this case, right CCA bifurcated above cricoid cartilage and divided into two branches of equal diameter in a middle-aged female cadaver. Medial one does not provide any branch and it appeared pale. It continued upward, entered carotid canal and it was confirmed as ICA. The ECA was found lateral to right ICA both in its origin and course. ECA provided lingual, facial and occipital branches. Superior thyroid artery was not identified, and it might be accidently damaged during dissection. It was noticed ECA was a content of carotid sheath. Vagus nerve first found between IJV and CCA and subsequently located between IJV and ECA. Third aortic arch contributed to development of CCA, leading part of ICA and entire part of ECA. Remaining part of ICA was developed from cranial portion of dorsal aorta. Therefore, any embryological deficiency in third aortic arch, dorsal aorta or changes inside of origin of ECA may lead to alteration in position of these vessels. Understanding vascular anatomy of neck is vital in precise interpretation of radiological images and neck surgeries.

DeepPAD: Detection of Peripheral Arterial Disease Using Deep Learning

Peripheral arterial disease (PAD) is a common circulatory disease caused by the deposition of fatty plaque on the arterial wall. Early detection and treatment of PAD are essential in preventing further cardiovascular and health complications. It was recently shown that PAD can be detected using an oscillometric device by characterizing the peripheral arterial system at different externally applied cuff pressures. However, the extraction of the complex relationship between the pattern of the oscillometric waveforms and the presence of PAD remained challenging. This study proposes a novel deep learning approach for the detection of PAD by capturing the peripheral arterial system behavior at different cuff pressures. The periodic pattern of the oscillometric pulses and their variations as a function of cuff pressure were modeled using a deep recurrent neural network based on the bidirectional long short-term memory and attention mechanism. The proposed model was evaluated by analyzing the raw oscillometric pulses as well as statistical features on data collected from 33 individuals (14 PAD and 19 normal). The results show a high accuracy of up to 94.8%, a sensitivity of up to 90.0%, and a specificity of up to 97.4% in detecting PAD. The proposed method provides new opportunities for noninvasive cardiovascular screening and early detection of PAD using the oscillometric principle.

Evaluation of Middle Cerebral Artery Symmetry: A Pilot Study for Clinical Application in Mechanical Thrombectomy

Endovascular mechanical thrombectomy (MT) has now evolved to become the standard treatment for acute ischemic stroke due to large vessel occlusion. Arterial perforation is a potential complication of MT, and the risk of this event during blind crossing the occlusion site has been elucidated. The intracranial arterial system shows morphological structural symmetry, so we investigated the utility of the bilateral symmetry of the proximal middle cerebral artery (MCA) as a preprocedural evaluation to predict hidden running course distal to the thrombus. This study retrospectively analyzed 191 consecutive patients (mean age, 67.5±15.5years; 100 women) who underwent time-of-flight-magnetic resonance angiography in our institution. Four landmarks of the MCA were assessed: division pattern, early branching pattern, length, and course pattern. Each geometric property was compared between cerebral hemispheres. Frequencies of symmetry and symmetry breaking were assessed. In 91% (bifurcation type, 87%; trifurcation type, 4%), branching patterns of the left and right M1 were symmetrical. Early frontal and/or temporal branches were observed in 31%, and the presence/absence of early branches was symmetrical in 70% cases. In 19%, M1 was classified as short M1, and classifications were identical between hemispheres in 74%. Running course of the M1 was symmetrical in 63%. Two or more parameters were symmetrical in 181 cases (95%). The symmetry of bilateral M1-2 structures was demonstrated in most cases from the perspectives of 4 parameters. The MCA symmetry can predict the running course of the MCA before crossing the occlusion site and shows potential benefits for neurointerventionalists.

Kounis Syndrome: A Novel Review

Kounis syndrome is characterised by a group of symptoms that manifests as unstable vasospastic or non-vasospastic angina secondary to a hypersensitivity reaction. It was first described by Kounis and Zavras in 1991 as the concurrence of an allergic response with an anaphylactic or anaphylactoid reaction and coronary artery spasm or even myocardial infarction. Since then, this condition has evolved to include a number of mast cell activation disorders associated with acute coronary syndrome. There are many triggering factors, including reactions to multiple medications, exposure to radiological contrast media, poison ivy, bee stings, shellfish, and coronary stents. In addition to coronary arterial involvement, Kounis syndrome comprises other arterial systems with similar physiologies, such as mesenteric and cerebral circulation resulting in ischemia / infraction of the vital organs. The Incidence of this condition is difficult to establish owing to the number of potential instigating factors and its relatively infrequent documentation in the literature. Anaphylaxis rarely manifests as a vasospastic acute coronary syndrome with or without the presence of underlying coronary artery disease. The variability in the underlying pathogenesis produces a wide clinical spectrum of this syndrome. Kounis syndrome is not just a single organ but also a complex multisystem and multiorgan arterial clinical conditions, it affects the coronary, mesenteric, and cerebral arteries and is accompanied by allergy hypersensitivity anaphylaxis involving Skin , respiratory system and vascular system in the context of anaesthesia, surgery, radiology ,oncology or even dental and psychiatric medicine , further it has significantly influences both morbidity and mortality. Kounis syndrome is caused by inflammatory mediators released during allergic insults, post inflammatory cell activation and interactions via multi directional stimuli. A platelet subset of 20% with high and low affinity IgE surface receptors is also involved in this process.

Peri-adventitial smooth muscle – inheritance of the iliac arterial system?

The histo-morphology of the arterial walls is typically made of 3 distinct layers or tunics designated as intima, media and adventitia. Based on the composition of the media, the arteries are classified into elastic and muscular types. The common iliac artery is an elastic artery, whereas its branches, the external and internal iliac arteries are muscular arteries. In this study, the presence of smooth muscle bundles outside the adventitia was noted in 93 samples taken from the iliac arterial system and the reasons for their presence have been hypothesized.

Dynamic vascular optical spectroscopy for monitoring peripheral arterial disease patients undergoing a surgical intervention

Peripheral arterial disease (PAD) patients experience a reduction in blood supply to the extremities caused by an accumulation of plaque in their arterial system. In advanced stages of PAD, surgical intervention is often required to reopen arteries and restore limb perfusion to avoid necrosis and amputations. To determine the success of an intervention, it is necessary to confirm that reperfusion was achieved after the intervention in areas of the foot that lacked perfusion before the intervention. The standard procedure to obtain this information is to perform repeated X-ray angiography. However, this approach requires a relatively high radiation dose and the extensive use of contrast agents. To overcome these issues, our lab has developed a system that uses dynamic vascular optical spectroscopy (DVOS) to monitor perfusion in the foot in real-time before, during, and after an intervention. In the explorative study presented in this paper, we monitored ten patients undergoing revascularization surgery. We found that there is a clear change in the DVOS signal in cases when reperfusion to affected areas in the foot is established. It was also possible to assess the effects that balloon inflations and deflations and contrast agent injections had on the downstream vasculature of the patients.

Influence of right coronary artery motion, flow pulsatility and non-Newtonian rheology on wall shear stress metrics.

The patchy distribution of atherosclerosis within the arterial system is consistent with a controlling influence of hemodynamic wall shear stress (WSS). Patterns of low, oscillatory and transverse WSS have been invoked to explain the distribution of disease in the aorta. Disease of coronary arteries has greater clinical importance but blood flow in these vessels may be complicated by their movement during the cardiac cycle. Previous studies have shown that time average WSS is little affected by the dynamic geometry, and that oscillatory shear is influenced more. Here we additionally investigate effects on transverse WSS. We also investigate the influence of non-Newtonian blood rheology as it can influence vortical structure, on which transverse WSS depends; Carreau-Yasuda models were used. WSS metrics were derived from numerical simulations of blood flow in a model of a moving right coronary artery which, together with a subject-specific inflow waveform, was obtained by MR imaging of a healthy human subject in a previous study. The results confirmed that time average WSS was little affected by dynamic motion and that oscillatory WSS was more affected. They additionally showed that transverse WSS and its non-dimensional analogue, the Cross Flow Index, were affected still further. This appeared to reflect time-varying vortical structures caused by the changes in curvature. The influence of non-Newtonian rheology was significant with some physiologically realistic parameter values, and hence may be important in certain subjects. Dynamic geometry and non-Newtonian rheology should be incorporated into models designed to produce maps of transverse WSS in coronary arteries.