Arterial Tortuosity

svMorph: Interactive Geometry-Editing Tools for Virtual Patient-Specific Vascular Anatomies

We propose svMorph, a framework for interactive virtual sculpting of patient-specific vascular anatomic models. Our framework includes three tools for the creation of tortuosity, aneurysms, and stenoses in tubular vascular geometries. These shape edits are performed via geometric operations on the surface mesh and vessel centerline curves of the input model. The tortuosity tool also uses the physics-based Oriented Particles method, coupled with linear blend skinning, to achieve smooth, elastic-like deformations. Our tools can be applied separately or in combination to produce simulation-suitable morphed models. They are also compatible with popular vascular modeling software, such as simvascular. To illustrate our tools, we morph several image-based, patient-specific models to create a range of shape changes and simulate the resulting hemodynamics via three-dimensional, computational fluid dynamics. We also demonstrate the ability to quickly estimate the hemodynamic effects of the shape changes via the automated generation of associated zero-dimensional lumped-parameter models.

HTAD patient pathway: Strategy for diagnostic work-up of patients and families with (suspected) heritable thoracic aortic diseases (HTAD). A statement from the HTAD working group of VASCERN

Heritable thoracic aortic diseases (HTAD) are rare pathologies associated with thoracic aortic aneurysms and dissection, which can be syndromic or non-syndromic. They may result from genetic defects. Associated genes identified to date are classified into those encoding components of the (a) extracellular matrix (b) TGFβ pathway and (c) smooth muscle contractile mechanism. Timely diagnosis allows for prompt aortic surveillance and prophylactic surgery, hence improving life expectancy and reducing maternal complications as well as providing reassurance to family members when a diagnosis is ruled out. This document is an expert opinion reflecting strategies put forward by medical experts and patient representatives involved in the HTAD Rare Disease Working Group of VASCERN. It aims to provide a patient pathway that improves patient care by diminishing time to diagnosis, facilitating the establishment of a correct diagnosis using molecular genetics when possible, excluding the diagnosis in unaffected persons through appropriate family screening and avoiding overuse of resources. It is being recommended that patients are referred to an expert centre for further evaluation if they meet at least one of the following criteria: (1) thoracic aortic dissection (<70 years if hypertensive; all ages if non-hypertensive), (2) thoracic aortic aneurysm (all adults with Z score >3.5 or 2.5-3.5 if non-hypertensive or hypertensive and <60 years; all children with Z score >3), (3) family history of HTAD with/without a pathogenic variant in a gene linked to HTAD, (4) ectopia lentis without other obvious explanation and (5) a systemic score of >5 in adults and >3 in children. Aortic imaging primarily relies on transthoracic echocardiography with magnetic resonance imaging or computed tomography as needed. Genetic testing should be considered in those with a high suspicion of underlying genetic aortopathy. Though panels vary among centers, for patients with thoracic aortic aneurysm or dissection or systemic features these should include genes with a definitive or strong association to HTAD. Genetic cascade screening and serial aortic imaging should be considered for family screening and follow-up. In conclusion, the implementation of these strategies should help standardise the diagnostic work-up and follow-up of patients with suspected HTAD and the screening of their relatives.

Association between the Angle of the Left Subclavian Artery and Procedural Time for Percutaneous Coronary Intervention in Patients with Acute Coronary Syndrome

Background

The effect of left subclavian artery tortuosity during percutaneous coronary intervention (PCI) in patients with acute coronary syndrome (ACS) remains unclear.

Methods

Of 245 ACS patients (from November 2019 and May 2021), 79 who underwent PCI via a left radial approach (LRA) were included. We measured the angle of the left subclavian artery in the coronal view on CT imaging as an indicator of the tortuosity and investigated the association between that angle and the clinical variables and procedural time.

Results

Patients with a left subclavian artery angle of a median of <70 degrees (severe tortuosity) were older (75.4 ± 11.7 vs. 62.9 ± 12.3 years, P < 0.001) and had a higher prevalence of female sex (42.1% vs. 14.6%, P=0.007), hypertension (94.7% vs. 75.6%, P=0.02), and subclavian artery calcification (73.7% vs. 34.2%, P < 0.001) than those with that ≥70 degrees. The left subclavian artery angle correlated negatively with the sheath cannulation to the first balloon time (ρ = -0.51, P < 0.001) and total procedural time (ρ = -0.32, P=0.004). A multiple linear regression analysis revealed that the natural log transformation of the sheath insertion to first balloon time was associated with a subclavian artery angle of <70 degrees (β = 0.45, P < 0.001).

Conclusion

Our study showed that lower left subclavian artery angles as a marker of the tortuosity via the LRA were strongly associated with a longer sheath insertion to balloon time and subsequent entire procedure time during the PCI.

Effect of Blood Transfusion on Cerebral Hemodynamics and Vascular Topology Described by Computational Fluid Dynamics in Sickle Cell Disease Patients

The main objective of this study was to demonstrate that computational fluid dynamics (CFD) modeling can be used to study the contribution of covert and overt vascular architecture to the risk for cerebrovascular disease in sickle cell disease (SCD) and to determine the mechanisms of response to therapy such as chronic red blood cell (cRBC) transfusions. We analyzed baseline (screening), pre-randomization and study exit magnetic resonance angiogram (MRA) images from 10 (5 each from the transfusion and observation arms) pediatric sickle SCD participants in the silent cerebral infarct transfusion (SIT) trial using CFD modeling. We reconstructed the intracranial portion of the internal carotid artery and branches and extracted the geometry using 3D Slicer. We cut specific portions of the large intracranial artery to include segments of the internal carotid, middle, anterior, and posterior cerebral arteries such that the vessel segment analyzed extended from the intracranial beginning of the internal carotid artery up to immediately after (~0.25 inches) the middle cerebral artery branching point. Cut models were imported into Ansys 2021R2/2022R1 and laminar and time-dependent flow simulation was performed. Change in time averaged mean velocity, wall shear stress, and vessel tortuosity were compared between the observation and cRBC arms. We did not observe a correlation between time averaged mean velocity (TAMV) and mean transcranial Doppler (TCD) velocity at study entry. There was also no difference in change in time average mean velocity, wall shear stress (WSS), and vessel tortuosity between the observation and cRBC transfusion arms. WSS and TAMV were abnormal for 2 (developed TIA) out of the 3 participants (one participant had silent cerebral infarctions) that developed neurovascular outcomes. CFD approaches allow for the evaluation of vascular topology and hemodynamics in SCD using MRA images. In this proof of principle study, we show that CFD could be a useful tool and we intend to carry out future studies with a larger sample to enable more robust conclusions.

Tortuosity of parent artery predicts in-stent stenosis after pipeline flow-diverter stenting for internal carotid artery aneurysms

Background and purpose

The relationship between the tortuosity of the parent artery and treatment outcomes is not well established. We investigate the association between parent artery tortuosity and flow diverter (FD) treatment outcomes in patients with internal carotid artery aneurysms in this study.

Methods

A retrospective review study was conducted to identify all patients with internal carotid artery aneurysms who were implanted with Pipeline embolization device (PED) between 2016 and 2020. The relationship between parent artery tortuosity and aneurysm complete occlusion (CO) and in-stent stenosis (ISS) was analyzed. The mathematical parameters “Curvature”, “torsion”, and “DM” extracted from the parent artery were utilized to quantify the parent artery tortuosity. A vascular narrowing of greater than 25% was categorized as ISS. Logistic regression analysis was used to identify significant independent predictors. Furthermore, we compared the performance of four machine learning algorithms and Logistic Regression model in predicting ISS.

Results

This research included 62 patients who with internal carotid artery aneurysms. In 49 (79%) cases, follow-up angiography (mean follow-up duration 11.7 ±7.3 months) revealed CO of the aneurysm. ISS was detected in 22 (35.5%) cases. According to univariate analysis, parent artery tortuosity and other variables were not associated with CO (p > 0.1). Maximum curvature (OR = 1.084; 95% CI, 1.008–1.165; p = 0.03) and DM (OR = 0.01; 95% CI, 0–0.488; p = 0.02) exhibited strong independent associations with ISS in multivariate analysis. The SVM model is superior to the conventional Logistic Regression model and the other models in predicting ISS.

Conclusions

The tortuosity of the parent artery may affect the treatment outcome of FD stenting. We found that parent artery tortuosity was associated with ISS, but not with aneurysm complete occlusion following PED stenting for internal carotid artery aneurysms in this study. Parent arteries with higher maximum curvature and lower DM were more likely to develop ISS.

Incidence, kinetics, and risk factors for intra- and extracranial cerebral arteriopathies in a newborn sickle cell disease cohort early assessed by transcranial and cervical color Doppler ultrasound

The risk of stroke in children with sickle cell disease (SCD) is detected by abnormal intracranial arterial time-averaged mean of maximum velocities (TAMVs ≥200 cm/s). Recently, extracranial internal carotid artery (eICA) arteriopathy has been reported, and a cross-sectional study showed that eICA-TAMVs ≥160 cm/s are significantly associated with eICA kinkings and stenosis. The cumulative incidence of and predictive risk factors for intracranial arteriopathy are well described in sickle cell anemia (SCA=SS/Sβ0) but are lacking for SC/Sβ+ children, as is the cumulative incidence of eICA arteriopathy. We report a prospective longitudinal cohort study including 493 children with SCD (398 SCA, 95 SC/Sβ+), all assessed by transcranial and cervical color Doppler ultrasound. Cerebral MRI/MRA data were available in 375 children with SCD and neck MRA in 365 children. eICA kinkings were defined as eICA tortuosities on neck MRA, with an internal acute angle between the two adjacent segments <90°. The median follow-up was 10.6 years. The cumulative incidence of kinkings was significantly lower in SC/Sβ+ children than in children with SCA, and no SC/Sβ+ child developed intra- or extracranial stenotic arteriopathy. The 10-year KM estimate of cumulative incidence (95% CI) for eICA-TAMVs ≥160 cm/s revealed its development in the 2nd year of life in children with SCA, reaching a plateau of 17.4% (13.2–21.6%) by about 10 years of age, while the plateau for eICA stenosis was 12.3% (8.3–16.3%). eICA assessment identified 13.5% (9.3–17.7%) patients at risk of stroke who were not detected by transcranial color Doppler ultrasound. We also show, for the first time, that in addition to a congenital origin, eICA kinkings sin patients with SCD can develop progressively with aging as a function of eICA-TAMVs, themselves related to anemia severity. Ongoing hydroxyurea treatment was significantly associated with a lower risk of abnormal intracranial arteriopathy and eICA kinkings. After adjustment with hydroxyurea, baseline low hemoglobin, high reticulocyte, and WBC counts remained independent risk factors for intracranial arteriopathy, while low hemoglobin and SEN β-haplotype number were independent risk factors for extracranial arteriopathy. The association between extracranial arteriopathy and SEN β-haplotype number suggested a genetic link between the ethnic origin and incidence of eICA kinkings. This prospective cohort study shows the importance of systematically assessing the eICA and of recording biological parameters during the 2nd year of life before any intensive therapy to predict the risk of cerebral arteriopathy and treat patients with severe baseline anemia.

Toward a Better Understanding of Sex- and Gender-Related Differences in Endovascular Stroke Treatment: A Scientific Statement From the American Heart Association/American Stroke Association

There are many unknowns when it comes to the role of sex in the pathophysiology and management of acute ischemic stroke. This is particularly true for endovascular treatment (EVT). It has only recently been established as standard of care; therefore, data are even more scarce and conflicting compared with other areas of acute stroke. Assessing the role of sex and gender as isolated variables is challenging because they are closely intertwined with each other, as well as with patients' cultural, ethnic, and social backgrounds. Nevertheless, a better understanding of sex- and gender-related differences in EVT is important to develop strategies that can ultimately improve individualized outcome for both men and women. Disregarding patient sex and gender and pursuing a one-size-fits-all strategy may lead to suboptimal or even harmful treatment practices. This scientific statement is meant to outline knowledge gaps and unmet needs for future research on the role of sex and gender in EVT for acute ischemic stroke. It also provides a pragmatic road map for researchers who aim to investigate sex- and gender-related differences in EVT and for clinicians who wish to improve clinical care of their patients undergoing EVT by accounting for sex- and gender-specific factors. Although most EVT studies, including those that form the basis of this scientific statement, report patient sex rather than gender, open questions on gender-specific EVT differences are also discussed.

Anatomic factors contributing to external iliac artery endofibrosis in high performance athletes

INTRODUCTION

External iliac artery endofibrosis (EIAE) classically presents in cyclists with intimal thickening of the affected arteries. We investigated possible anatomical predisposing factors including psoas muscle hypertrophy, arterial tortuosity, inguinal ligament compression, and arterial kinking via case-control comparison of symptomatic and contralateral limbs.

METHODS

All patients with unilateral EIAE treated surgically at our institution were reviewed. Each patient's symptomatic side was compared with their contralateral side using paired t-tests. Psoas hypertrophy was quantified by transverse cross-sectional area (CSA) at L4, L5, and S1 vertebral levels, and inguinal ligament compression was measured as anterior-posterior distance between inguinal ligament and underlying bone. Tortuosity index for diseased segments and arterial kinking were measured on TeraRecon.

RESULTS

Of 33 patients operated on for EIAE from 2004-2021, 27 with available imaging presented with unilateral disease, more commonly left-sided (63%). Most (96%) had external iliac involvement and 26% had ≥2 segments affected: 19% common iliac artery, 15% common femoral artery. The symptomatic limb had greater mean L5 psoas CSA (1450 mm² vs. 1396 mm², mean difference 54 mm², P=0.039). There were no significant differences in L4 or S1 psoas hypertrophy, tortuosity, inguinal ligament compression, or arterial kinking. 63% underwent patch angioplasty and 85% underwent additional inguinal ligament release. 84% reported postoperative satisfaction, which was associated with greater difference in psoas hypertrophy at L4 (p=0.022).

CONCLUSIONS

Psoas muscle hypertrophy is most pronounced at L5 and is associated with symptomatic EIAE. Preferential hypertrophy of the affected side correlates with improved outcomes, suggesting psoas muscle hypertrophy as a marker of disease severity.

Altered Mitochondrial Opa1-Related Fusion in Mouse Promotes Endothelial Cell Dysfunction and Atherosclerosis

Flow (shear stress)-mediated dilation (FMD) of resistance arteries is a rapid endothelial response involved in tissue perfusion. FMD is reduced early in cardiovascular diseases, generating a major risk factor for atherosclerosis. As alteration of mitochondrial fusion reduces endothelial cells’ (ECs) sprouting and angiogenesis, we investigated its role in ECs responses to flow. Opa1 silencing reduced ECs (HUVECs) migration and flow-mediated elongation. In isolated perfused resistance arteries, FMD was reduced in Opa1^+/− mice, a model of the human disease due to Opa1 haplo-insufficiency, and in mice with an EC specific Opa1 knock-out (EC-Opa1). Reducing mitochondrial oxidative stress restored FMD in EC-Opa1 mice. In isolated perfused kidneys from EC-Opa1 mice, flow induced a greater pressure, less ATP, and more H₂O₂ production, compared to control mice. Opa1 expression and mitochondrial length were reduced in ECs submitted in vitro to disturbed flow and in vivo in the atheroprone zone of the mouse aortic cross. Aortic lipid deposition was greater in Ldlr^−/--Opa1^+/- and in Ldlr^−/--EC-Opa1 mice than in control mice fed with a high-fat diet. In conclusion, we found that reduction in mitochondrial fusion in mouse ECs altered the dilator response to shear stress due to excessive superoxide production and induced greater atherosclerosis development.

An Alternative Methodology to Compute the Geometric Tortuosity in 2D Porous Media Using the A-Star Pathfinding Algorithm

Geometric tortuosity is an essential characteristic to consider when studying a porous medium’s morphology. Knowing the material’s tortuosity allows us to understand and estimate the different diffusion transport properties of the analyzed material. Geometric tortuosity is useful to compute parameters, such as the effective diffusion coefficient, inertial factor, and diffusibility, which are commonly found in porous media materials. This study proposes an alternative method to estimate the geometric tortuosity of digitally created two-dimensional porous media. The porous microstructure is generated by using the PoreSpy library of Python and converted to a binary matrix for the computation of the parameters involved in this work. As a first step, porous media are digitally generated with porosity values from 0.5 to 0.9; then, the geometric tortuosity is determined using the A-star algorithm. This approach, commonly used in pathfinding problems, improves the use of computational resources and complies with the theory found in the literature. Based on the obtained results, the best geometric tortuosity–porosity correlations are proposed. The selection of the best correlation considers the coefficient of determination value (99.7%) with a confidence interval of 95%.

Wall Shear Stress Alteration: a Local Risk Factor of Atherosclerosis

PURPOSE OF REVIEW

Wall shear stress describes the mechanical influence of blood flow on the arterial wall. In this review, we discuss the role of the wall shear stress in the development of atherosclerosis and its complications.

RECENT FINDINGS

Areas with chronically low, oscillating wall shear stress are most prone to plaque development and include outer bifurcation walls and inner walls of arches. In some diseases, patients have lower wall shear stress even in straight arterial segments; also, these findings were associated with atherosclerosis. High wall shear stress develops in the distal part (shoulder) of a stenosis and contributes to plaque destabilization. Wall shear stress changes are involved in the development of atherosclerosis. They are not fully understood yet and act in concert with tangential wall stress.

Accuracy of vascular tortuosity measures using computational modelling

Severe coronary tortuosity has previously been linked to low shear stresses at the luminal surface, yet this relationship is not fully understood. Several previous studies considered different tortuosity metrics when exploring its impact of on the wall shear stress (WSS), which has likely contributed to the ambiguous findings in the literature. Here, we aim to analyze different tortuosity metrics to determine a benchmark for the highest correlating metric with low time-averaged WSS (TAWSS). Using Computed Tomography Coronary Angiogram (CTCA) data from 127 patients without coronary artery disease, we applied all previously used tortuosity metrics to the left main coronary artery bifurcation, and to its left anterior descending and left circumflex branches, before modelling their TAWSS using computational fluid dynamics (CFD). The tortuosity measures included tortuosity index, average absolute-curvature, root-mean-squared (RMS) curvature, and average squared-derivative-curvature. Each tortuosity measure was then correlated with the percentage of vessel area that showed a < 0.4 Pa TAWSS, a threshold associated with altered endothelial cell cytoarchitecture and potentially higher disease risk. Our results showed a stronger correlation between curvature-based versus non-curvature-based tortuosity measures and low TAWSS, with the average-absolute-curvature showing the highest coefficient of determination across all left main branches (p < 0.001), followed by the average-squared-derivative-curvature (p = 0.001), and RMS-curvature (p = 0.002). The tortuosity index, the most widely used measure in literature, showed no significant correlation to low TAWSS (p = 0.86). We thus recommend the use of average-absolute-curvature as a tortuosity measure for future studies.

Relation Between Coronary Tortuosity and Vasomotor Dysfunction in Patients Without Obstructed Coronaries?

Background: A large proportion of patients with angina and no obstructive coronary artery disease (ANOCA) has underlying coronary vasomotor dysfunction (CVDys), which can be diagnosed by a coronary function test (CFT). Coronary tortuosity is a common angiographic finding during the CFT. Yet, no data exist on the association between vasomotor dysfunction and coronary tortuosity.

Aim: To investigate the association between CVDys and coronary tortuosity in patients with ANOCA

Methods: All consecutive ANOCA patients who underwent clinically indicated CFT between February 2019 and November 2020 were included. CFT included acetylcholine spasm testing to diagnose epicardial or microvascular spasm, and adenosine testing to diagnose microvascular dysfunction (MVD). MVD was defined as an index of microvascular resistance (IMR) ≥ 25 and/or coronary flow reserve (CFR) <2.0. Coronary tortuosity, was scored (no, mild, moderate or severe) based on the angles of the curvatures in the left anterior descending (LAD) artery on angiography.

Results: In total, 228 patients were included (86% female, mean age 56 ± 9 years). We found coronary artery spasm in 81% of patients and MVD in 45% of patients (15%: abnormal CFR, 30%: abnormal IMR). There were 73 patients with no tortuosity, 114 with mild tortuosity, 41 with moderate tortuosity, and no patients with severe tortuosity. No differences were found in cardiovascular risk factors or medical history, and the prevalence of CVDys did not differ between the no tortuosity, mild tortuosity and moderate tortuosity group (82, 82, and 85%, respectively).

Conclusion: In this study, CVDys was not associated with coronary tortuosity. Future experimental and clinical studies on the complex interplay between coronary tortuosity, wall shear stress, endothelial dysfunction and coronary flow are warranted.

Increased intracranial arterial tortuosity is associated with worse cardiovascular outcome in patients with Loeys-Dietz syndrome

The aim of our study was to evaluate the association between intracranial arterial tortuosity and cardiovascular outcome in patients with Loeys-Dietz syndrome (LDS). We performed a retrospective analysis of all patients with genetically confirmed LDS who underwent at least one brain MRA at our institution (n = 32); demographic and clinical features were evaluated in relation to the tortuosity of intracranial arteries as measured by tortuosity index (TI), which was calculated using the formula: [(centerline length) / (straight-line length)-1] × 100. Receiver operating characteristic curve analysis for intracranial TI and the binary end point of aortic surgery showed vertebrobasilar TI (VBTI) to be the best classifier among the examined arterial segments (AUC = 0.822). Patients with higher VBTI showed a greater incidence of aortic surgery (p < 0.001) and underwent more surgical and endovascular procedures (p = 0.006), with a higher rate of operations (p = 0.002). Kaplan-Meier analysis showed a significantly longer surgery-free survival in patients with lower arterial tortuosity (p < 0.001). At multivariate analysis, higher VBTI was associated with an increased risk of surgery (p < 0.001), which was independent of gene mutation and patient age. Increased VBTI is a marker of adverse cardiovascular outcome in patients with LDS, which can be easily measured on brain MRA, and may be useful in the management of this heterogeneous patient population.

Prediction of radial crossover in acute coronary syndromes: derivation and validation of the MATRIX score

BACKGROUND

The radial artery is recommended by international guidelines as the default vascular access in patients with acute coronary syndromes (ACS) managed invasively. However, crossover from radial to femoral access is required in 4-10% of cases and has been associated with worse outcomes. No standardised algorithm exists to predict the risk of radial crossover.

AIMS

We sought to derive and externally validate a risk score to predict radial crossover in patients with ACS managed invasively.

METHODS

The derivation cohort consisted of 4,197 patients with ACS undergoing invasive management via the randomly allocated radial access from the MATRIX trial. Using logistic regression, we selected predictors of radial crossover and developed a numerical risk score. External validation was accomplished among 3,451 and 491 ACS patients managed invasively and randomised to radial access from the RIVAL and RIFLE-STEACS trials, respectively.

RESULTS

The MATRIX score (age, height, smoking, renal failure, prior coronary artery bypass grafting, ST-segment elevation myocardial infarction, Killip class, radial expertise) showed a c-index for radial crossover of 0.71 (95% CI: 0.67-0.75) in the derivation cohort. Discrimination ability was modest in the RIVAL (c-index: 0.64; 95% CI: 0.59-0.67) and RIFLE-STEACS (c-index: 0.66; 95% CI: 0.57-0.75) cohorts. A cut-off of ≥41 points was selected to identify patients at high risk of radial crossover.

CONCLUSIONS

The MATRIX score is a simple eight-item risk score which provides a standardised tool for the prediction of radial crossover among patients with ACS managed invasively. This tool can assist operators in anticipating and better addressing difficulties related to transradial procedures, potentially improving outcomes.

Venous tortuosity as a novel biomarker of rupture risk in arteriovenous malformations: ARI score

BACKGROUND

Risk of rupture in arteriovenous malformations (AVMs) varies considerably among series. Hemodynamic factors, especially within the venous side of the circuit, seem to be responsible but are not yet well defined. We analyzed tortuosity in the draining vein as a potential new marker of rupture in AVMs, and propose a simple index to predict AVM bleeding.

METHODS

A retrospective analysis of the venous angioarchitecture of brain AVMs was carried out at our center from 2013 to 2021, with special attention to venous tortuosity. After univariate analysis, the features of interest were combined to construct several predictive models using multivariate logistic regression. The best model proposed was the new AVM rupture index (ARI), which was then validated in an independent cohort.

RESULTS

68 AVMs were included in the first step and 32 in the validation cohort. Venous tortuosity, expressed as at least one curve >180°, was a significant predictor of rupture (p=0.023). The proposed bleeding index consisted of: venous tortuosity (any curve of >180°), single draining vein, and paraventricular/infratentorial location. It seems to be a robust evaluation tool, with an area under the receiver operating characteristic (AUROC) curve of 0.806 (95% CI 0.714 to 0.899), consistently replicated in the independent sample (AUROC 0.759 (95% CI 0.607 to 0.911)), and with an inter-rater kappa coefficient of 0.81 .

CONCLUSIONS

Venous tortuosity may serve as a predictor of bleeding in AVMs that warrants further investigation. This likely new marker was one of the three elements of the proposed ARI. ARI outperformed the predictive accuracy of previous scores, and remained consistent in an independent cohort.

Treatment with the Prolyl Hydroxylase Inhibitor JNJ Promotes Abdominal Aortic Aneurysm Progression in Diabetic Mice

OBJECTIVE

Prolyl hydroxylase domain containing proteins (PHD) rigorously regulate intracellular hypoxia inducible factor-1 (HIF-1) protein expression and activity. Diabetes impairs PHD activity and attenuates abdominal aortic aneurysm (AAA) progression. The extent to which dysregulated PHD activity contributes to diabetes mediated AAA suppression remains undetermined.

METHODS

AAAs were induced in diabetic and non-diabetic male C57BL/6J mice via intra-aortic elastase infusion. A PHD inhibitor (JNJ-42041935, aka "JNJ", 150 mmol/kg) or vehicle alone was administered daily starting one day prior to AAA induction for 14 days. Influences on AAA progression was assessed via ultrasonography and histopathology. Expression of aortic HIF-1α, three of its target genes and macrophage derived mediators were assayed via quantitative reverse transcription polymerase chain reaction. Aneurysmal sections from AAA patients with and without diabetes (two patients in each group) were immunostained for HIF-1α and vascular endothelial growth factor (VEGF)-A.

RESULTS

Expression of HIF-1α target genes (erythropoietin, VEGF-A, and glucose transporter-1) was reduced by 45% - 95% in experimental diabetic aortas. Diameter enlargement was similarly limited, as were mural elastin degradation, leukocyte infiltration, and neo-angiogenesis (reduced capillary density and length) on histopathology. Pre-treatment with JNJ prior to AAA initiation augmented aortic HIF-1α target gene expression and aneurysm progression in diabetic mice, along with macrophage VEGF-A and matrix metalloproteinase 2 mRNA expression. No differences were noted in HIF-1α or VEGF-A expression on aortic immunohistochemical staining of human aortic tissue as a function of diabetes status.

CONCLUSION

Small molecule PHD inhibitor treatment reduces or offsets impairment of experimental AAA progression in hyperglycemic mice, highlighting the potential contribution of dysregulated PHD activity to diabetes mediated aneurysm suppression.

Outcomes of Mechanical Thrombectomy for Patients With Stroke Presenting With Low Alberta Stroke Program Early Computed Tomography Score in the Early and Extended Window

IMPORTANCE

Limited data are available about the outcomes of mechanical thrombectomy (MT) for real-world patients with stroke presenting with a large core infarct.

OBJECTIVE

To investigate the safety and effectiveness of MT for patients with large vessel occlusion and an Alberta Stroke Program Early Computed Tomography Score (ASPECTS) of 2 to 5.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used data from the Stroke Thrombectomy and Aneurysm Registry (STAR), which combines the prospectively maintained databases of 28 thrombectomy-capable stroke centers in the US, Europe, and Asia. The study included 2345 patients presenting with an occlusion in the internal carotid artery or M1 segment of the middle cerebral artery from January 1, 2016, to December 31, 2020. Patients were followed up for 90 days after intervention. The ASPECTS is a 10-point scoring system based on the extent of early ischemic changes on the baseline noncontrasted computed tomography scan, with a score of 10 indicating normal and a score of 0 indicating ischemic changes in all of the regions included in the score.

EXPOSURE

All patients underwent MT in one of the included centers.

MAIN OUTCOMES AND MEASURES

A multivariable regression model was used to assess factors associated with a favorable 90-day outcome (modified Rankin Scale score of 0-2), including interaction terms between an ASPECTS of 2 to 5 and receiving MT in the extended window (6-24 hours from symptom onset).

RESULTS

A total of 2345 patients who underwent MT were included (1175 women [50.1%]; median age, 72 years [IQR, 60-80 years]; 2132 patients [90.9%] had an ASPECTS of ≥6, and 213 patients [9.1%] had an ASPECTS of 2-5). At 90 days, 47 of the 213 patients (22.1%) with an ASPECTS of 2 to 5 had a modified Rankin Scale score of 0 to 2 (25.6% [45 of 176] of patients who underwent successful recanalization [modified Thrombolysis in Cerebral Ischemia score ≥2B] vs 5.4% [2 of 37] of patients who underwent unsuccessful recanalization; P = .007). Having a low ASPECTS (odds ratio, 0.60; 95% CI, 0.38-0.85; P = .002) and presenting in the extended window (odds ratio, 0.69; 95% CI, 0.55-0.88; P = .001) were associated with worse 90-day outcome after controlling for potential confounders, without significant interaction between these 2 factors (P = .64).

CONCLUSIONS AND RELEVANCE

In this cohort study, more than 1 in 5 patients presenting with an ASPECTS of 2 to 5 achieved 90-day functional independence after MT. A favorable outcome was nearly 5 times more likely for patients with low ASPECTS who had successful recanalization. The association of a low ASPECTS with 90-day outcomes did not differ for patients presenting in the early vs extended MT window.

Prevalence and Disease Spectrum of Extracoronary Arterial Abnormalities in Spontaneous Coronary Artery Dissection

Question

What is the prevalence of fibromuscular dysplasia, aneurysms, dissection, and tortuosity in extracoronary arteries of patients who developed a spontaneous coronary artery dissection (SCAD)?

Findings

In this case series including 173 patients with SCAD, using magnetic resonance angiography with blinded interpretation of the findings, 32% of the patients had fibromuscular dysplasia, 8% had aneurysms, and 2% had dissections; the prevalence of arterial tortuosity was similar in cases and controls. Extracoronary vascular events over a median 5-year follow-up were rare.

Meaning

The findings of this blinded analysis suggest that, in patients with SCAD, severe multivessel fibromuscular dysplasia, aneurysms, and dissections are infrequent and seldom associated with clinically evident vascular events.

Importance

Spontaneous coronary artery dissection (SCAD) has been associated with fibromuscular dysplasia (FMD) and other extracoronary arterial abnormalities. However, the prevalence, severity, and clinical relevance of these abnormalities remain unclear.

Objective

To assess the prevalence and spectrum of FMD and other extracoronary arterial abnormalities in patients with SCAD vs controls.

Design, Setting, and Participants

This case series included 173 patients with angiographically confirmed SCAD enrolled between January 1, 2015, and December 31, 2019. Imaging of extracoronary arterial beds was performed by magnetic resonance angiography (MRA). Forty-one healthy individuals were recruited to serve as controls for blinded interpretation of MRA findings. Patients were recruited from the UK national SCAD registry, which enrolls throughout the UK by referral from the primary care physician or patient self-referral through an online portal. Participants attended the national SCAD referral center for assessment and MRA.

Exposures

Both patients with SCAD and healthy controls underwent head-to-pelvis MRA (median time between SCAD event and MRA, 1 [IQR, 1-3] year).

Main Outcome and Measures

The diagnosis of FMD, arterial dissections, and aneurysms was established according to the International FMD Consensus. Arterial tortuosity was assessed both qualitatively (presence or absence of an S curve) and quantitatively (number of curves ≥45%; tortuosity index).

Results

Of the 173 patients with SCAD, 167 were women (96.5%); mean (SD) age at diagnosis was 44.5 (7.9) years. The prevalence of FMD was 31.8% (55 patients); 16 patients (29.1% of patients with FMD) had involvement of multiple vascular beds. Thirteen patients (7.5%) had extracoronary aneurysms and 3 patients (1.7%) had dissections. The prevalence and degree of arterial tortuosity were similar in patients and controls. In 43 patients imaged with both computed tomographic angiography and MRA, the identification of clinically significant remote arteriopathies was similar. Over a median 5-year follow-up, there were 2 noncardiovascular-associated deaths and 35 recurrent myocardial infarctions, but there were no primary extracoronary vascular events.

Conclusions and Relevance

In this case series with blinded analysis of patients with SCAD, severe multivessel FMD, aneurysms, and dissections were infrequent. The findings of this study suggest that, although brain-to-pelvis imaging allows detection of remote arteriopathies that may require follow-up, extracoronary vascular events appear to be rare.

Tortuosity Index Calculations in Retinal Images: Some Criticalities Arising from Commonly Used Approaches

A growing body of research in retinal imaging is recently considering vascular tortuosity measures or indexes, with definitions and methods mostly derived from cardiovascular research. However, retinal microvasculature has its own peculiarities that must be considered in order to produce reliable measurements. This study analyzed and compared various derived metrics (e.g., TI, TI_avg, TI*CV) across four existing computational workflows. Specifically, the implementation of the models on two critical OCT images highlighted main pitfalls of the methods, which may fail in reliably differentiating a highly tortuous image from a normal one. A tentative, encouraging approach to mitigate the issue on the same OCT exemplificative images is described in the paper, based on the suggested index TI*CV.

Comparative Study of Human and Murine Aortic Biomechanics and Hemodynamics in Vascular Aging

Introduction: Aging has many effects on the cardiovascular system, including changes in structure (aortic composition, and thus stiffening) and function (increased proximal blood pressure, and thus cardiac afterload). Mouse models are often used to gain insight into vascular aging and mechanisms of disease as they allow invasive assessments that are impractical in humans. Translation of results from murine models to humans can be limited, however, due to species-specific anatomical, biomechanical, and hemodynamic differences. In this study, we built fluid-solid-interaction (FSI) models of the aorta, informed by biomechanical and imaging data, to compare wall mechanics and hemodynamics in humans and mice at two equivalent ages: young and older adults. Methods: For the humans, 3-D computational models were created using wall property data from the literature as well as patient-specific magnetic resonance imaging (MRI) and non-invasive hemodynamic data; for the mice, comparable models were created using population-based properties and hemodynamics as well as subject-specific anatomies. Global aortic hemodynamics and wall stiffness were compared between humans and mice across age groups. Results: For young adult subjects, we found differences between species in pulse pressure amplification, compliance and resistance distribution, and aortic stiffness gradient. We also found differences in response to aging between species. Generally, the human spatial gradients of stiffness and pulse pressure across the aorta diminished with age, while they increased for the mice. Conclusion: These results highlight key differences in vascular aging between human and mice, and it is important to acknowledge these when using mouse models for cardiovascular research.

A clinical perspective on endovascular stroke treatment biomechanics

Acute ischemic stroke (AIS) is caused by blockage of an arterial blood vessel in the brain by a thrombus, which interrupts oxygen supply to the brain parenchyma. The goal of endovascular stroke treatment (mechanical thrombectomy) is to restore blood flow as quickly and completely as possible. There are numerous factors that influence endovascular treatment success. They can be broadly grouped into a) factors related to blood vessels, b) factors related to the thrombus, c) factors related to endovascular treatment technique and tools and d) operator-related factors. While blood vessel and tgthro thrombus-related factors are mostly non-modifiable in the acute setting, operator and technique-related factors can be modified, and extensive research is currently being done to investigate the complex interplay of all these variables, and to optimize the modifiable factors to the maximum possible extent. In this review, we will describe these factors and how they interact with each other in detail, and outline some of their practical implications. We will conclude with a short summary and outlook on future directions for optimizing endovascular treatment success.

Retinal arteriolar tortuosity and fractal dimension are associated with long-term cardiovascular outcomes in people with type 2 diabetes

AIMS/HYPOTHESIS

Our aim was to determine whether quantitative retinal traits in people with type 2 diabetes are independently associated with incident major cardiovascular events including CHD and stroke.

METHODS

A total of 1066 men and women with type 2 diabetes, aged 65-74 years, were followed up over 8 years in the population-based Edinburgh Type 2 Diabetes Study. Using retinal photographs taken at baseline and specialist software, a number of quantitative retinal traits were measured, including arteriolar and venular widths and tortuosity as well as fractal dimension (a measure of the branching pattern complexity of the retinal vasculature network). Incident CHD events occurring during follow-up included fatal and non-fatal myocardial infarction, first episodes of angina and coronary interventions for CHD. Incident cerebrovascular events included fatal and non-fatal stroke or transient ischaemic attack. Cox proportional hazard regression analyses were performed to identify the association of the retinal traits with cardiovascular events in the population with retinal data available (n = 1028).

RESULTS

A total of 200 participants had an incident cardiovascular event (139 CHD and 61 cerebrovascular events). Following adjustment for age and sex, arteriolar tortuosity and fractal dimension were associated with cerebrovascular events (HR 1.27 [95% CI 1.02, 1.58] and HR 0.74 [95% CI 0.57, 0.95], respectively), including with stroke alone (HR 1.30 [95% CI 1.01, 1.66] and HR 0.73 [95% CI 0.56, 0.97], respectively). These associations persisted after further adjustment for established cardiovascular risk factors (HR 1.26 [95% CI 1.01, 1.58] and HR 0.73 [95% CI 0.56, 0.94], respectively). Associations generally reduced in strength after a final adjustment for the presence of diabetic retinopathy, but the association of fractal dimension with incident cerebrovascular events and stroke retained statistical significance (HR 0.73 [95% CI 0.57, 0.95] and HR 0.72 [95% CI 0.54, 0.97], respectively). Associations of retinal traits with CHD were generally weak and showed no evidence of statistical significance.

CONCLUSIONS/INTERPRETATION

Arteriolar tortuosity and fractal dimension were associated with incident cerebrovascular events, independent of a wide range of traditional cardiovascular risk factors including diabetic retinopathy. These findings suggest potential for measurements of early retinal vasculature change to aid in the identification of people with type 2 diabetes who are at increased risk from stroke.

Application of covered stent graft in the treatment of complex carotid artery lesions: A single center experience

PURPOSE

To assess the clinical efficiency and imaging outcome of applying covered stent grafts for the treatment of complex carotid artery lesions.

METHOD

A total of 39 consecutive patients with carotid artery lesions treated with covered stent grafts at our institution from December 2016 to December 2019 were reviewed. Two kinds of stent including self-expandable covered stent (Viabahn; W. L. Gore & Associates) and balloon-expandable covered stent (Willis; Microport) were applied. The angiograms immediately after the procedure, perioperative complications, and follow-up outcomes were recorded.

RESULT

Based on imaging features, 11 patients exhibited pseudoaneurysms, 23 patients had blood blister-like aneurysms (BBAs), and five patients were carotid cavernous fistulas. A total of 40 stent implantations were performed, including nine Viabahn stents and 31 Willis stents. Two patients received double implants of Willis stents. Stent failed to perform for one patient due to tortuous parent artery. The angiography reports immediately after the procedure showed that the lesions in 36 patients were completely occluded, whereas two patients had minimal endoleaks. With respect to the occurrence of procedural complications, an aneurysm ruptured during the procedure in one case, which resulted in CCF, and acute in-stent thrombosis occurred in another case. Clinical and angiographic follow-up (11.2±2.4 months) sessions were conducted for 38 patients and a complete lesion exclusion was achieved in 36 patients. The minimal endoleak persisted in one patient and another patient experienced recurrence with stent migration, leading to ipsilateral blepharoptosis. However, none of the patients developed hemorrhage or ischemia and in-stent stenosis was not observed.

CONCLUSION

Covered stent grafts appear to be a safe and feasible for the treatment of complex carotid artery lesions. Despite the potential for stent delivery failure as well as endoleak and procedure-related complications, covered stent grafts should be considered when selecting the optimal treatment strategy.

Comparison of Swine and Human Computational Hemodynamics Models for the Study of Coronary Atherosclerosis

Coronary atherosclerosis is a leading cause of illness and death in Western World and its mechanisms are still non completely understood. Several animal models have been used to 1) study coronary atherosclerosis natural history and 2) propose predictive tools for this disease, that is asymptomatic for a long time, aiming for a direct translation of their findings to human coronary arteries. Among them, swine models are largely used due to the observed anatomical and pathophysiological similarities to humans. However, a direct comparison between swine and human models in terms of coronary hemodynamics, known to influence atherosclerotic onset/development, is still lacking. In this context, we performed a detailed comparative analysis between swine- and human-specific computational hemodynamic models of coronary arteries. The analysis involved several near-wall and intravascular flow descriptors, previously emerged as markers of coronary atherosclerosis initiation/progression, as well as anatomical features. To do that, non-culprit coronary arteries (18 right–RCA, 18 left anterior descending–LAD, 13 left circumflex–LCX coronary artery) from patients presenting with acute coronary syndrome were imaged by intravascular ultrasound and coronary computed tomography angiography. Similarly, the three main coronary arteries of ten adult mini-pigs were also imaged (10 RCA, 10 LAD, 10 LCX). The geometries of the imaged coronary arteries were reconstructed (49 human, 30 swine), and computational fluid dynamic simulations were performed by imposing individualized boundary conditions. Overall, no relevant differences in 1) wall shear stress-based quantities, 2) intravascular hemodynamics (in terms of helical flow features), and 3) anatomical features emerged between human- and swine-specific models. The findings of this study strongly support the use of swine-specific computational models to study and characterize the hemodynamic features linked to coronary atherosclerosis, sustaining the reliability of their translation to human vascular disease.

Constrained Mixture Models of Soft Tissue Growth and Remodeling - Twenty Years After

Soft biological tissues compromise diverse cell types and extracellular matrix constituents, each of which can possess individual natural configurations, material properties, and rates of turnover. For this reason, mixture-based models of growth (changes in mass) and remodeling (change in microstructure) are well-suited for studying tissue adaptations, disease progression, and responses to injury or clinical intervention. Such approaches also can be used to design improved tissue engineered constructs to repair, replace, or regenerate tissues. Focusing on blood vessels as archetypes of soft tissues, this paper reviews a constrained mixture theory introduced twenty years ago and explores its usage since by contrasting simulations of diverse vascular conditions. The discussion is framed within the concept of mechanical homeostasis, with consideration of solid-fluid interactions, inflammation, and cell signaling highlighting both past accomplishments and future opportunities as we seek to understand better the evolving composition, geometry, and material behaviors of soft tissues under complex conditions.

Cerebrovascular phenotypes in mouse models of Alzheimer's disease

Alzheimer's disease (AD) is a devastating neurological degenerative disorder and is the most common cause of dementia in the elderly. Clinically, AD manifests with memory and cognitive decline associated with deposition of hallmark amyloid beta (Aβ) plaques and neurofibrillary tangles (NFTs). Although the mechanisms underlying AD remains unclear, two hypotheses have been proposed. The established amyloid hypothesis states that Aβ accumulation is the basis of AD and leads to formation of NFTs. In contrast, the two-hit vascular hypothesis suggests that early vascular damage leads to increased accumulation of Aβ deposits in the brain. Multiple studies have reported significant morphological changes of the cerebrovasculature which can result in severe functional deficits. In this review, we delve into known structural and functional vascular alterations in various mouse models of AD and the cellular and molecular constituents that influence these changes to further disease progression. Many studies shed light on the direct impact of Aβ on the cerebrovasculature and how it is disrupted during the progression of AD. However, more research directed towards an improved understanding of how the cerebrovasculature is modified over the time course of AD is needed prior to developing future interventional strategies.

MRI-Based Investigation of Association Between Cerebrovascular Structural Alteration and White Matter Hyperintensity Induced by High Blood Pressure

BACKGROUND

High blood pressure (BP) is a common risk factor for cerebral small vessel disease including white matter hyperintensity (WMH). Whether increased BP exacerbates WMH by impacting cerebral vascular morphologies remains poorly studied.

PURPOSE

To determine the relationships among high BP, cerebrovascular morphologies, and WMH in elderly individuals.

STUDY TYPE

Cohort.

SUBJECTS

Eight hundred sixty-three participants (54.2% female) from the Taizhou Imaging Study without clinical evidence of neurologic disorders were included in the analyses.

FIELD STRENGTH/SEQUENCE

3.0 T; time-of-flight magnetic resonance angiography (TOF MRA); T2 fluid-attenuated inversion recovery (FLAIR); T1 magnetization-prepared rapid gradient-echo; gradient echo T2*-weighted; diffusion tensor imaging; pulsed arterial spin labeling.

ASSESSMENT

Cerebrovascular morphologic measurements were quantified based on the TOF MRA images, including vessel density, radius, tortuosity, and branch number. WMH lesion volumes (WMHV) and WMH lesion counts (WMHC) were calculated automatically based on the T2 FLAIR images.

STATISTICAL TESTS

Multivariable linear regression analysis and path analysis with a linear single-mediator model were employed. A P value <0.05 was considered statistically significant.

RESULTS

Higher BP, especially diastolic BP, was significantly correlated with lower cerebrovascular density (β = -104) and lower branch numbers (β = -0.02). Although decreased tortuosity (β = -1.25) and increased radius (β = 93.8) were correlated with BP, no significant relationship of tortuosity (β = -4.6 × 10^-4 , P = 0.58) or radius (β = 0.03, P = 0.08) with BP in small vessels was found. The proportion of small vessels decreased as BP increased (SBP: β = -6.6 × 10^-4 ; DBP: β = -9.0 × 10^-4 ). Similarly, increased WMHV and WMHC were associated with decreased vessel density (volumes: β = -24, counts: β = -127), decreased tortuosity (volumes: β = -0.08, counts: β = -0.53), and increased radius (volumes: β = 12.6, counts: β = 86.6). Path analyses suggested an association between high BP and WMHs that were mediated by cerebrovascular morphologic changes.

DATA CONCLUSION

Structural alterations of cerebral vessels induced by high BP are correlated with WMH. This result suggested that elevated BP might be one of the pathophysiological mechanisms involving in the co-occurrence of cerebrovascular alteration and small vessel disease.

LEVEL OF EVIDENCE

1 Technical Efficacy Stage: 1.

Oxidative Stress Mediates Vascular Tortuosity

Vascular tortuosity is associated with various disorders and is being increasingly detected through advances in imaging techniques. The underlying mechanisms for vascular tortuosity, however, remain unclear. Here, we tested the hypothesis that oxidative stress mediates the generation of tortuous vessels. We used the bilateral common carotid artery (CCA) ligation model to induce vascular tortuosity. Both young and adult rats showed basilar artery tortuous morphological changes one month after bilateral CCA ligation. These tortuous changes were permanent but more pronounced in the adult rats. Microarray and real-time PCR analysis revealed that these tortuous changes were accompanied by the induction of oxidative stress-related genes. Moreover, the indicated model in rabbits showed that tortuous morphological changes to the basilar artery were suppressed by antioxidant treatment. These results are highly suggestive of the significance of oxidative stress in the development of vascular tortuosity. Although further studies will be needed to elucidate the possible mechanisms by which oxidative stress enhances vascular tortuosity, our study also points toward possible prophylaxis and treatment for vascular tortuosity.

Percutaneous treatment of acute axillary artery occlusion after percutaneous coronary intervention: A case report

The JR guide catheter is preferred for operability; however, we should pay more attention to the guide catheter in the case of radial artery approach with severe vessel tortuosity especially in patients with hypertension or in older female patients.

How Cerebral Vessel Tortuosity Affects Development and Recurrence of Aneurysm: Outer Curvature versus Bifurcation Type

Background and Purpose

Previous studies have assessed the relationship between cerebral vessel tortuosity and intracranial aneurysm (IA) based on two-dimensional brain image analysis. We evaluated the relationship between cerebral vessel tortuosity and IA according to the hemodynamic location using three-dimensional (3D) analysis and studied the effect of tortuosity on the recurrence of treated IA.

Methods

We collected clinical and imaging data from patients with IA and disease-free controls. IAs were categorized into outer curvature and bifurcation types. Computerized analysis of the images provided information on the length of the arterial segment and tortuosity of the cerebral arteries in 3D space.

Results

Data from 95 patients with IA and 95 controls were analyzed. Regarding parent vessel tortuosity index (TI; P<0.01), average TI (P<0.01), basilar artery (BA; P=0.02), left posterior cerebral artery (P=0.03), both vertebral arteries (VAs; P<0.01), and right internal carotid artery (P<0.01), there was a significant difference only in the outer curvature type compared with the control group. The outer curvature type was analyzed, and the occurrence of an IA was associated with increased TI of the parent vessel, average, BA, right middle cerebral artery, and both VAs in the logistic regression analysis. However, in all aneurysm cases, recanalization of the treated aneurysm was inversely associated with increased TI of the parent vessels.

Conclusions

TIs of intracranial arteries are associated with the occurrence of IA, especially in the outer curvature type. IAs with a high TI in the parent vessel showed good outcomes with endovascular treatment.

Prevalence of Cervical Artery Abnormalities on CTA in Patients with Spontaneous Coronary Artery Dissection: Fibromuscular Dysplasia, Dissection, Aneurysm, and Tortuosity

BACKGROUND AND PURPOSE

Little is known about associations between spontaneous coronary artery dissection and cervical artery abnormalities. This study sought to assess the prevalence of cervical artery abnormalities among patients with spontaneous coronary artery dissection.

MATERIALS AND METHODS

A retrospective analysis was completed of patients who underwent CTA neck imaging as part of arterial assessment following the diagnosis of spontaneous coronary artery dissection. The internal carotid and vertebral arteries were evaluated for the presence of fibromuscular dysplasia, dissection and/or pseudoaneurysm, ectasia and/or aneurysmal dilation, atherosclerosis, and webs. Carotid tortuosity was categorized into kinks, loops, coils, and retrojugular and/or retropharyngeal carotid courses; vertebral tortuosity was classified by subjective analysis of severity.

RESULTS

Two hundred fourteen patients were included in the final cohort, of whom 205 (95.8%) were women; the average age was 54.4 years. Fibromuscular dysplasia was the most frequently observed abnormality (83 patients; 38.8%), followed by dissections and/or pseudoaneurysms (n = 28; 13.1%), ectasia and/or aneurysmal dilation (n = 22; 10.3%), and carotid webs (n = 10; 4.7%). At least 1 type of carotid tortuosity was present in 99 patients (46.3%). The majority (n = 185; 86.4%) of patients had no carotid atherosclerosis; and 26 (12.2%) had mild; 3 (1.4%), moderate; and 0, severe carotid atherosclerosis.

CONCLUSIONS

The most common abnormality in the cervical artery vasculature of patients with spontaneous coronary artery dissection is fibromuscular dysplasia. Cervical dissections were higher than previously reported but were not observed in most patients.

Increased tortuosity of bilateral distal internal carotid artery is associated with white matter hyperintensities

BACKGROUND

Although the pathophysiology of white matter hyperintensities remains unclear, we can recently explore the possible relationship with white matter hyperintensities by using quantitative parameter.

PURPOSE

To demonstrate the relationship between bilateral distal internal carotid arterial tortuosity and total brain white matter hyperintensities volume in elderly individuals.

MATERIAL AND METHODS

A total of 345 patients (age > 65 years) with brain magnetic resonance (MR) examinations were retrospectively included (44.1% men; mean age = 72.1 ± 6.25 years; 55.9% ≥ 70 years). We measured the Tortuosity Index (TI) of the bilateral distal internal carotid artery and basilar artery on MR angiography imaging, and white matter hyperintensities volume on fluid-attenuated inversion recovery MR sequence. Multiple linear regression was used to assess the association of the TI with quantitatively derived brain white matter hyperintensity volume, after adjusting for demographics (age, sex), vascular risk factors (hypertension, diabetes, heart disease), and vessel diameters, total intracranial volume (TIV).

RESULTS

Increased tortuosity of bilateral distal internal carotid artery was associated with greater burden of white matter hyperintensity volume (right: β = 11.223, P = 0.016; left: β = 20.701, P < 0.001). This relationship was independent of age and hypertension, both of which have been considered the strongest risk factors for white matter hyperintensities.

CONCLUSION

Our results suggest that tortuosity of the bilateral distal internal carotid artery is associated with white matter hyperintensities, independent of age and hypertension.

Does Carotid Artery Tortuosity Play a Role in Stroke?

PURPOSE

To explore the association between carotid artery length and tortuosity, and the occurrence of stroke.

MATERIAL AND METHODS

In this retrospective study, IRB approved, 411 consecutive patients (males: 245; median age: 56 ± 12 years, age range: 21-93 years) with anterior circulation ischemic stroke were included. Only patients that underwent CTA within 7 days were considered and stroke caused by cardiac embolism and thoracic aorta embolism were excluded. For each patient, both carotid arteries were considered, and the ICA, CCA-ICA length and tortuosity were calculated. Inter-observer analysis was quantified with the Bland-Altman test. Mann-Whitney test and logistic regression analysis were also calculated to test the association between length and tortuosity with the occurrence of stroke.

RESULTS

In the final analysis, 166 patients (males: 72; median age: 54 ± 12 years, age range: 24-89 years) with anterior circulation ischemic stroke that were admitted to our hospital between February 2008 and December 2013 were included. The results showed a good concordance for the length of the vessels with a mean variation of 0.7% and 0.5% for CCA-ICA and ICA length respectively an for the tortuosity with a mean variation of 0.2% and -0.4% for CCA-ICA and ICA respectively. The analysis shows a statistically significant association between the tortuosity index of the ICA and CCA-ICA sides with stroke (P value = 0.0001 in both cases) and these findings were confirmed also with the logistic regression analysis.

CONCLUSION

Results of this study suggest that tortuosity index is associated with the presence of stroke whereas the length of the carotid arteries does not play a significant role.

Elastic fibers during aging and disease

Elastic fibers are essential constituents of the extracellular matrix of higher vertebrates and endow several tissues and organs including lungs, skin and blood vessels with elasticity and resilience. During the human lifespan, elastic fibers are exposed to a variety of enzymatic, chemical and biophysical influences, and accumulate damage due to their low turnover. Aging of elastin and elastic fibers involves enzymatic degradation, oxidative damage, glycation, calcification, aspartic acid racemization, binding of lipids and lipid peroxidation products, carbamylation and mechanical fatigue. These processes can trigger an impairment or loss of elastic fiber function and are associated with severe pathologies. There are different inherited or acquired pathological conditions, which influence the structure and function of elastic fibers and microfibrils predominantly in the cardiorespiratory system and skin. Inherited elastic-fiber pathologies have a direct or indirect impact on elastic-fiber formation due to mutations in the fibrillin genes (fibrillinopathies), in the elastin gene (elastinopathies) or in genes encoding proteins that are associated with microfibrils or elastic fibers. Acquired elastic-fiber pathologies appear age-related or as a result of multiple factors impairing tissue homeostasis. This review gives an overview on the fate of elastic fibers over the human lifespan in health and disease.

Recurrent spontaneous coronary artery dissection

Introduction: Spontaneous coronary artery dissection (SCAD) is a cause of non-atherosclerotic acute coronary syndrome and sudden cardiac death that predominantly impacts young and middle-aged women. In addition to the challenges of acute SCAD including arrhythmias, heart failure, and recurrent chest pain, de novo recurrent SCAD occurs in 5-29% of patients. Recurrent SCAD presents both a psychological burden and a significant cardiac risk to patients. Research regarding SCAD recurrence risk has been growing and can guide providers and patients alike.Areas covered: This review provides up-to-date information about many aspects of SCAD with a focus on SCAD recurrence. PubMed articles were reviewed through October 2020, with particular focus on clinical studies and original research. The resulting literature was scrutinized for information on SCAD recurrence. SCAD-associated conditions, genetic data, clinical characteristics, medications, and aspects of post-SCAD care are summarized.Expert Opinion: SCAD recurrence poses a concerning risk for patients with SCAD. Conditions such as hypertension and severe coronary tortuosity may be associated with recurrence. More research is needed to further elucidate risk factors for recurrence and clarify interventions, such as beta blocker therapy, that may reduce recurrence risk.

Treatment and Predictors of Recurrent Internal Carotid Artery In-Stent Restenosis

PURPOSE

We aimed to examine the effectiveness of different therapeutic options for and to identify the possible risk factors of recurrent internal carotid artery (ICA) in-stent restenosis (ISR).

METHODS

Forty-six ICA ISRs, which were reintervened at least once, were retrospectively analyzed regarding clinical and imaging characteristics, as well as invasive treatment type (percutaneous transluminal angioplasty [PTA] with a plain balloon, PTA with a drug-eluting balloon [DEB], re-stenting) used.

RESULTS

The median follow-up was 29.5 months (IQR, 8.5-52.8 months) in patients who underwent reintervention for ICA ISR. Stent occlusion occurred in 3 patients (6.5%). One ISR recurrence was noted in 10 patients (21.7%); reintervention was carried out in 7 cases (7/10 [70%]; PTA, N = 5; PTA with a DEB, N = 1; re-stenting, N = 1), while 3 patients (3/10; 30%) received best medical treatment. Two ISR recurrences were observed in 3 patients (6.5%); all of them underwent reintervention (PTA, N = 1; PTA with a DEB, N = 2). Three ISR recurrences were seen in 1 patient (2.2%), who was treated with PTA. No recurrence was observed in those patients, who had DEB treatment. Multiple logistic regression analysis revealed statin therapy to be a protective factor against recurrent ISR (OR, 0.17; 95% CI, 0.03-0.84; P = .029).

CONCLUSION

Our study suggests that PTA with a DEB is the most effective for the treatment of recurrent ISR, and confirms the importance of statin use in patients who have had a carotid reintervention.

Association of Tortuous Common Carotid Artery with Abnormal Distribution of the Ansa Cervicalis: A Case Report

In the current study, we display a rare association of an aberrant innervation of the sternocleidomastoid muscle by the ansa cervicalis (AC) with a tortuous common carotid artery (TCCA). In specific, in a male cadaver we observed on the right side of the cervical region, a nerval branch of remarkable size originating from the most distal part of the AC's superior root and after piercing the superior belly of the omohyoid muscle innervated the distal portion of the sternocleidomastoid muscle. Furthermore, we noticed a tortuous course of the initial part of the right common carotid artery. We discuss the surgical significance of the awareness of AC's variations during neurotisation of the recurrent laryngeal nerve in cases of its damage, as well as the importance of aberrant innervation of the sternocleidomastoid muscle by AC for the preservation of muscle's functionality after accessory nerve's damage. Furthermore, we highlight the fact, that the knowledge of the relatively uncommon variant, such as TCCA is crucial for the physician in order to proceed more effectively in differential diagnosis of a palpable mass of the anterior cervical region or deal with symptoms such as dyspnea, dysphagia or symptoms of cerebrovascular insufficiency.

Neonatal Arterial Tortuosity and Adult Aortic Aneurysm-Is There a Missing Link?-A Case Report

We report a novel case of a full term newborn with non-immune fetal hydrops and arterial tortuosity mimicking a double aortic arch, and cranial fractures in the immediate neonatal period. The infant had no classic features of neonatal arterial tortuosity syndrome or Loeys Dietz syndrome apart from bilateral inguinal hernia. He also had skeletal manifestations in the form of fractures in the neonatal period without any trauma during birth and without clinical evidence of Osteogenesis Imperfecta. A heterozygous missense variant of uncertain significance was detected in MYH11 gene which is increasingly recognized to be belonging to the familial/hereditary thoracic aneurysm and aortic dissection group of disorders. Fetal hydrops as an association with arterial tortuosity has not been reported in the literature. We hypothesize the possible mechanism behind developing fetal hydrops in this case and discuss the genetic and phenotypic heterogeneity of the Familial Thoracic Aortic Aneurysm and Dissection (FTAAD) group of conditions highlighting the unique phenotypic and genotypic presentations. We recommend a high index of suspicion and vigilance in the early detection of such potentially lethal conditions with sequelae also in adulthood.

Mechanics-driven mechanobiological mechanisms of arterial tortuosity

Arterial tortuosity manifests in many conditions, including hypertension, genetic mutations predisposing to thoracic aortopathy, and vascular aging. Despite evidence that tortuosity disrupts efficient blood flow and that it may be an important clinical biomarker, underlying mechanisms remain poorly understood but are widely appreciated to be largely biomechanical. Many previous studies suggested that tortuosity may arise via an elastic structural buckling instability, but the novel experimental-computational approach used here suggests that tortuosity arises from mechanosensitive, cell-mediated responses to local aberrations in the microstructural integrity of the arterial wall. In particular, computations informed by multimodality imaging show that aberrations in elastic fiber integrity, collagen alignment, and collagen turnover can lead to a progressive loss of structural stability that entrenches during the development of tortuosity. Interpreted in this way, microstructural defects or irregularities of the arterial wall initiate the condition and hypertension is a confounding factor.

Increased arterial stiffness in males with abdominal aortic aneurysm

Background

Abdominal aortic aneurysm (AAA), a localized dilatation of the abdominal aorta, has a prevalence of about 1.5%–3% among 65‐ to 70‐year‐old males in Europe. AAA confers an increased risk of developing major cardiovascular events in addition to the risk of aneurysm rupture. The aim of this study was to evaluate whether the arterial wall distensibility is altered in subjects with AAA.

Methods

Two hundred and eighty‐four male subjects (182 with AAA and 102 controls) were enrolled in the study. Arterial wall distensibility was evaluated using non‐invasive applanation tonometry to measure regional pulse wave velocity between the carotid and femoral arteries and the carotid and radial arteries. In addition, blood pressure was measured, and the pulse pressure waveform was analysed.

Results

Higher aortic augmentation index (25.1% versus 20.6%; p < .001) and higher aortic pulse wave velocity (12.3 m/s versus 10.9 m/s; p < .001) were demonstrated in the AAA cohort. The slightly higher arm pulse wave velocity in the AAA group (9.4 m/s versus 9.1 m/s; p < .05) was abolished after adjusting for mean arterial blood pressure.

Conclusions

Males with AAA have decreased aortic wall distensibility and enhanced reflection waves in central aorta during systole. These results imply that increased arterial wall stiffness may be a contributing factor to the overall higher cardiovascular risk seen in patients with AAA.

Intracranial Arterial Tortuosity in Marfan Syndrome and Loeys-Dietz Syndrome: Tortuosity Index Evaluation Is Useful in the Differential Diagnosis

BACKGROUND AND PURPOSE

The association of arterial tortuosity and connective tissue diseases is widely reported in the literature, but only a few studies were based on a quantitative evaluation of this arterial phenotype, and none of the latter examined the intracranial vasculature. The aim of this study was to evaluate the degree of intracranial arterial tortuosity in patients with Marfan syndrome and those with Loeys-Dietz syndrome, and to assess its usefulness in the differential diagnosis.

MATERIALS AND METHODS

We performed a retrospective analysis of 68 patients with genetically confirmed Marfan syndrome (n = 36) or Loeys-Dietz syndrome (n = 32), who underwent at least 1 MRA of the brain at our institution. Fifty-two controls were randomly selected among patients who presented with headache and without any known comorbidity. Tortuosity indexes of 4 intracranial arterial segments were measured on a 3D volume-rendered angiogram by using the following formula: [Formula: see text].

RESULTS

Both Marfan syndrome and Loeys-Dietz syndrome showed a significantly higher tortuosity index compared with controls in all examined vessels. The tortuosity index of the vertebrobasilar system showed an excellent interrater reliability (intraclass correlation coefficient, 0.99) and was the strongest independent predictor of Loeys-Dietz syndrome in patients with connective tissue disease (P = .002), with a 97% specificity for this pathology when its value was > 60.

CONCLUSIONS

The tortuosity index of intracranial arteries is an easily calculated and highly reproducible measure, which shows a high specificity for Marfan syndrome and Loeys-Dietz syndrome and may be useful in differentiating these 2 entities.

Tortuous ulnar artery presenting as left distal forearm mass

Knowledge of anatomic variation in vasculature is critical to safe medical intervention as conduits vary in morphology, architecture, and course. Tortuosity is a common anatomic variant in certain arterial beds; however, its prevalence in ulnar arteries is not well documented in the literature. Here we report two cases of tortuous ulnar arteries in patients being evaluated for upper extremity hemodialysis access.

Image-based scaling laws for somatic growth and pulmonary artery morphometry from infancy to adulthood

Pulmonary artery (PA) morphometry has been extensively explored in adults, with particular focus on intra-acinar arteries. However, scaling law relationships for length and diameter of extensive preacinar PAs by age have not been previously reported for in vivo human data. To understand preacinar PA growth spanning children to adults, we performed morphometric analyses of all PAs visible in the computed tomography (CT) and magnetic resonance (MR) images from a healthy subject cohort [n = 16; age: 1-51 yr; body surface area (BSA): 0.49-2.01 m²]. Subject-specific anatomic PA models were constructed from CT and MR images, and morphometric information-diameter, length, tortuosity, bifurcation angle, and connectivity-was extracted and sorted into diameter-defined Strahler orders. Validation of Murray's law, describing optimal scaling exponents of radii for branching vessels, was performed to determine how closely PAs conform to this classical relationship. Using regression analyses of vessel diameters and lengths against orders and patient metrics (BSA, age, height), we found that diameters increased exponentially with order and allometrically with patient metrics. Length increased allometrically with patient metrics, albeit weakly. The average tortuosity index of all vessels was 0.026 ± 0.024, average bifurcation angle was 28.2 ± 15.1°, and average Murray's law exponent was 2.92 ± 1.07. We report a set of scaling laws for vessel diameter and length, along with other morphometric information. These provide an initial understanding of healthy structural preacinar PA development with age, which can be used for computational modeling studies and comparison with diseased PA anatomy.NEW & NOTEWORTHY Pulmonary artery (PA) morphometry studies to date have focused primarily on large arteries and intra-acinar arteries in either adults or children, neglecting preacinar arteries in both populations. Our study is the first to quantify in vivo preacinar PA morphometry changes spanning infants to adults. For preacinar arteries > 1 mm in diameter, we identify scaling laws for vessel diameters and lengths with patient metrics of growth and establish a healthy PA morphometry baseline for most preacinar PAs.