Evaluation of the carotid artery using wavelet-based analysis of the pulse wave signal

<p>The use of pulse wave analysis may assist cardiologists in diagnosing patients with vascular diseases. However, it is not common in clinical practice to interpret and analyze pulse wave data and utilize them to detect the abnormalities of the signal. This paper presents a novel approach to the clinical application of pulse waveform analysis using the wavelet technique by decomposing the normal and pathology signal into many levels. The discrete wavelet transform (DWT) decomposes the carotid arterial pulse wave (CAPW) signal, and the continuous wavelet transform (CWT) creates images of the decomposed signal. The wavelet analysis technique in this work aims to strengthen the medical benefits of the pulse wave. The obtained results show a clear difference between the signal and the images of the arterial pathologies in comparison with normal ones. The certain distinct that were achieved are promising but further improvement may be required in the future.</p>

Characterization and validation of a chronic retinal neovascularization rabbit model by evaluating the efficacy of anti-angiogenic and anti-inflammatory drugs

AIM: To establish a rabbit model with chronic condition of retinal neovascularization (RNV) induced by intravitreal (IVT) injection of DL-2-aminoadipic acid (DL-AAA), a retinal glial (Müller) cell toxin, extensive characterization of DL-AAA induced angiographic features and the suitability of the model to evaluate anti-angiogenic and anti-inflammatory therapies for ocular vascular diseases. METHODS: DL-AAA (80 mmol/L) was administered IVT into both eyes of Dutch Belted rabbit. Post DL-AAA delivery, clinical ophthalmic examinations were performed weekly following modified McDonald-Shadduck Scoring System. Color fundus photography, fluorescein angiography (FA), and optical coherence tomography (OCT) procedures were performed every 2 or 4wk until stable retinal vascular leakage was observed. Once stable retinal leakage (12wk post DL-AAA administration) was established, anti-vascular endothelial growth factor (VEGF) (bevacizumab, ranibizumab and aflibercept) and anti-inflammatory (triamcinolone, TAA) drugs were tested for their efficacy after IVT administration. Fluorescein angiograms were scored before and after treatment following a novel grading system, developed for the DL-AAA rabbit model. RESULTS: Post DL-AAA administration, eyes were presented with moderate to severe retinal/choroidal inflammation which was accompanied by intense vitreous flare and presence of inflammatory cells in the vitreous humor. Retinal hemorrhage was restricted to the tips of neo-retinal vessels. FA revealed maximum retinal vascular leakage at 2wk after DL-AAA injection and then persisted as evidenced by stable mean FA scores in weeks 8 and 12. Retinal vascular angiographic and tomographic features were stable and consistent up to 36mo among two different staggers induced for RNV at two different occasions. Day 7, mean FA scores showed that 1 µg/eye of bevacizumab, ranibizumab, aflibercept and 2 µg/eye of TAA suppress 65%, 90%, 100% and 50% retinal vascular leakage, respectively. Day 30, bevacizumab and TAA continued to show 66% and 44% suppression while ranibizumab effect was becoming less effective (68%). In contrast, aflibercept was still able to fully (100%) suppress vascular leakage on day 30. On day 60, bevacizumab, ranibizumab and TAA showed suppression of 7%, 12%, and 9% retinal vascular leakage, respectively, however, aflibercept continued to be more effective showing 50% suppression of vascular leakage. CONCLUSION: The DL-AAA rabbit model mimics RNV angiographic features like RNV and chronic retinal leakage. Based on these features the DL-AAA rabbit model provides an invaluable tool that could be used to test the therapeutic efficacy and duration of action of novel anti-angiogenic formulations, alone or in combination with anti-inflammatory compounds.

Fluid-structure interaction simulation of tissue degradation and its effects on intra-aneurysm hemodynamics

Tissue degradation plays a crucial role in vascular diseases such as atherosclerosis and aneurysms. Computational modeling of vascular hemodynamics incorporating both arterial wall mechanics and tissue degradation has been a challenging task. In this study, we propose a novel finite element method-based approach to model the microscopic degradation of arterial walls and its interaction with blood flow. The model is applied to study the combined effects of pulsatile flow and tissue degradation on the deformation and intra-aneurysm hemodynamics. Our computational analysis reveals that tissue degradation leads to a weakening of the aneurysmal wall, which manifests itself in a larger deformation and a smaller von Mises stress. Moreover, simulation results for different heart rates, blood pressures and aneurysm geometries indicate consistently that, upon tissue degradation, wall shear stress increases near the flow-impingement region and decreases away from it. These findings are discussed in the context of recent reports regarding the role of both high and low wall shear stress for the progression and rupture of aneurysms.

Coronary Artery Stenting Affects Wall Shear Stress Topological Skeleton

Despite the important advancements in the stent technology for the treatment of diseased coronary arteries, major complications still affect the post-operative long-term outcome. The stent-induced flow disturbances, and especially the altered wall shear stress (WSS) profile at the strut level, play an important role in the pathophysiological mechanisms leading to stent thrombosis (ST) and in-stent restenosis (ISR). In this context, the analysis of the WSS topological skeleton is gaining more and more interest by extending the current understanding of the association between local hemodynamics and vascular diseases. The present study aims to analyze the impact that a deployed coronary stent has on the WSS topological skeleton. Computational fluid dynamics simulations were performed in three stented human coronary artery geometries reconstructed from clinical images. The selected cases presented stents with different designs (i.e., two contemporary drug eluting stents and one bioresorbable scaffold) and included regions with stent malapposition or overlapping. A recently proposed Eulerian-based approach was applied to analyze the WSS topological skeleton features. The results highlighted that the presence of single or multiple stents within a coronary artery markedly impacts the WSS topological skeleton. In particular, repetitive patterns of WSS divergence were observed at the luminal surface, highlighting a WSS contraction action proximal to the struts and a WSS expansion action distal to the struts. This WSS action pattern was independent from the stent design. In conclusions, these findings could contribute to a deeper understanding of the hemodynamic-driven processes underlying ST and ISR.

Changes in micro- and central hemodynamic parameters in rats under the action of acetylsalicylic acid and its coordination compounds with metals

Introduction. The cutaneous blood circulation is a representative model both for studying the mechanisms of vascular diseases and for assessing the current state of the central hemodynamics in preclinical researches of various chemical compounds. Aim. The changes in the parameters of cutaneous microcirculation and central hemodynamics (heart rate and blood pressure) were studied in the animals under the action of acetylsalicylic acid and its coordination compounds with cations of cobalt, zinc, nickel and manganese at a dose of 20 mg/kg. Materials and methods. The research was conducted using the laser Doppler flowmetry method on the Lazma-MC device (manufactured by RPE Lazma, Russia) and the NIBP200A system (Biopac Systems, Inc., USA). Results. The study shows that animals develop bradycardia, and microcirculation and central hemodynamics change in two ways after the introduction of acetylsalicylic acid and the tested metal salicylates. These ways are hypotension-related hyperemia (acetylsalicylic acid and cobalt salicylate) and ischemia (zinc, nickel and manganese salicylates) associated with hypertension. Conclusion. The obtained data confirm the cardiotropic activity of new coordination compounds. The data also prove that the generation of the acetylsalicylic acid derivatives allows enhancing it physiological effects, as well as obtaining completely new molecules. The molecules are different from the precursor one and are necessary for the production of effective drugs.

Applications of Artificial Intelligence in Non-cardiac Vascular Diseases: A Bibliographic Analysis

Research output related to artificial intelligence (AI) in vascular diseases has been poorly investigated. The aim of this study was to evaluate scientific publications on AI in non-cardiac vascular diseases. A systematic literature search was conducted using the PubMed database and a combination of keywords and focused on three main vascular diseases (carotid, aortic and peripheral artery diseases). Original articles written in English and published between January 1995 and December 2020 were included. Data extracted included the date of publication, the journal, the identity, number, affiliated country of authors, the topics of research, and the fields of AI. Among 171 articles included, the three most productive countries were USA, China, and United Kingdom. The fields developed within AI included: machine learning (n = 90; 45.0%), vision (n = 45; 22.5%), robotics (n = 42; 21.0%), expert system (n = 15; 7.5%), and natural language processing (n = 8; 4.0%). The applications were mainly new tools for: the treatment (n = 52; 29.1%), prognosis (n = 45; 25.1%), the diagnosis and classification of vascular diseases (n = 38; 21.2%), and imaging segmentation (n = 38; 21.2%). By identifying the main techniques and applications, this study also pointed to the current limitations and may help to better foresee future applications for clinical practice.

A retrospective cohort study on European Reference Network for Rare Vascular Diseases 5 outcome measures for Hereditary Haemorrhagic Telangiectasia in Denmark

Background Hereditary Haemorrhagic Telangiectasia (HHT) is an autosomal dominant disorder characterized by several clinical symptoms including epistaxis, arteriovenous malformations (AVM), and telangiectasia. In 2018, European Reference Network for Rare Vascular Diseases (VASCERN) recommended five outcome measures for HHT-patients to guide health care providers, some with limited experience in treating HHT, and thereby maximizing the number of HHT-patients receiving good care. The outcome measures cover the following aspects: (1) 90% of the patients should receive a pulmonary AVM (PAVM) screening; (2) 90% of the patients should receive written advice on nosebleed; (3) 70% should be assessed for iron deficiency; (4) 100% of the patients should receive written advice on antibiotic (AB) prophylaxis prior to dental and surgical procedures, and (5) 100% of relevant patients should receive written advice on pregnancy. We have introduced the outcome measures as Benchmarks in our HHT-centre and wanted to evaluate the extend of implementation we have achieved. We constantly struggle to secure the best possible treatment of our HHT-patients. Methods The study was a non-interventional retrospective study. Data was collected manually from patient records and from the Danish HHT-database. Results A total of 180 HHT-patients were included, all diagnosed in the period from January 1st, 2016, to December 31st, 2020. All patients were screened for PAVM. We could confirm that 66% of patients who had epistaxis received thoroughly advice. Assessment for iron deficiency was performed in 80% of the adult patients. Thoroughly advice on AB prophylaxis was documented in 75%. Thoroughly advice on pregnancy was documented in 80% of female patients 15–45 years of age. There were no significant differences over time for any of the outcome measures. Conclusions The Danish HHT-centre reached the target threshold for outcome measures 1 and 3. It could not be documented that the target thresholds for outcome measures 2, 4, and 5 were achieved. As information and education are a very important part of HHT care, focus on and documentation that all patients receive the relevant advice must be a priority in order to ensure best care.

Temporal Artery Vascular Diseases

In the presence of temporal arteritis, clinicians often refer to the diagnosis of giant cell arteritis (GCA). However, differential diagnoses should also be evoked because other types of vascular diseases, vasculitis or not, may affect the temporal artery. Among vasculitis, Anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis is probably the most common, and typically affects the peri-adventitial small vessel of the temporal artery and sometimes mimics giant cell arteritis, however, other symptoms are frequently associated and more specific of ANCA-associated vasculitis prompt a search for ANCA. The Immunoglobulin G4-related disease (IgG4-RD) can cause temporal arteritis as well. Some infections can also affect the temporal artery, primarily an infection caused by the varicella-zoster virus (VZV), which has an arterial tropism that may play a role in triggering giant cell arteritis. Drugs, mainly checkpoint inhibitors that are used to treat cancer, can also trigger giant cell arteritis. Furthermore, the temporal artery can be affected by diseases other than vasculitis such as atherosclerosis, calcyphilaxis, aneurysm, or arteriovenous fistula. In this review, these different diseases affecting the temporal artery are described.