Papers by Andrew Nicolaides
Advances in Therapy, Feb 13, 2019
Chronic venous disease (CVD) is widespread, underdiagnosed, and can progress to chronic venous in... more Chronic venous disease (CVD) is widespread, underdiagnosed, and can progress to chronic venous insufficiency and venous ulcers, which can require extensive treatment and hospitalization. These conditions negatively impact patient quality of life and place substantial burdens on healthcare resources. The two main risk factors for CVD are age and obesity. Thus, with the growing prevalence of obesity and the increasing longevity of the population, the burden of CVD is expected to increase dramatically in the coming decades. Appropriate lifestyle changes and care, which may include treatment with venoactive drugs, can slow disease progression, improve quality of life, and are likely to reduce healthcare costs. Physicians should be aware of this growing problem and of the effective treatments available for CVD. We recommend the accompanying short summaries from a symposium held at the recent European Venous Forum as a means for our colleagues to learn more about the burden and suffering associated with CVD. Funding: Servier.
Advances in Therapy, Aug 11, 2022
The importance of chronic venous disease (CVD), as a cause of reduced quality of life and increas... more The importance of chronic venous disease (CVD), as a cause of reduced quality of life and increased costs to healthcare systems, is expected to rise in parallel with population aging and the increasing prevalence of obesity. Venoactive drugs (VADs) are frequently used to treat the symptoms and signs of CVD. The most commonly used and widely studied VAD, micronised purified flavonoid fraction (MPFF), is effective at all stages of CVD, and has been shown to significantly reduce leg pain, leg heaviness and swelling, as well as ankle oedema and functional discomfort, in clinical trials. Recently, experiments employing animal models of CVD have demonstrated that MPFF has anti-inflammatory and venotonic effects at the microvalve level, and a pilot clinical study in patients with CVD has provided support for these findings. Collectively, these results suggest that early initiation of MPFF treatment may have the potential to favourably alter the clinical course of the disease, although further clinical data are required to confirm these findings. International guidelines on CVD management strongly recommend MPFF to reduce symptoms and improve quality of life. Studies are now needed to investigate the impact of long-term treatment on disease progression.
Phlebolymphology, 2009
Because the venous system is in many respects more complex than the arterial system, because chro... more Because the venous system is in many respects more complex than the arterial system, because chronic venous disease (CVD) is common in Western populations, and because both specialists and general practitioners have to deal with this disease, there is a need for practical support regarding CVD management in daily practice. This article summarizes the most recent guidelines regarding the place of venoactive drugs (VADs) such as Daflon 500 mg in the management of this disease. In addition, it makes suggestions regarding expected improvements in future guideline documents.
Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 2006
Stroke is the third leading cause of death in the western world and the major cause of disability... more Stroke is the third leading cause of death in the western world and the major cause of disability in adults. The type and stenosis of extracranial carotid artery disease is often responsible for ischemic strokes, transient ischemic attacks (TIAs) or amaurosis fugax (AF). The identification and grading of stenosis can be done using gray scale ultrasound scans. The appearance of B-scan pictures containing various granular structures makes the use of texture analysis techniques suitable for computer assisted tissue characterization purposes. The objective of this study is to investigate the usefulness of variogram analysis in the assessment of ultrasound plague morphology. The variogram estimates the variance of random fields, from arbitrary samples in space. We explore stationary random field models based on the variogram, which can be applied in ultrasound plaque imaging leading to a Computer Aided Diagnosis (CAD) system for the early detection of symptomatic atherosclerotic plaques. Non-parametric tests on the variogram coefficients show that the coefficients coming from symptomatic versus asymptomatic plaques come from distinct distributions. Furthermore, we show significant improvement in class separation, when a log point-transformation is applied to the images, prior to variogram estimation. Model fitting using least squares is explored for anisotropic variograms along specific directions. Comparative classification results, show that variogram coefficients can be used for the early detection of symptomatic cases, and also exhibit the largest class distances between symptomatic and asymptomatic plaque images, as compared to over 60 other texture features, used in the literature.
Journal of Endovascular Therapy, 2001
ICAROS (Imaging in Carotid Angioplasties and Risk Of Stroke) is a multicenter international regis... more ICAROS (Imaging in Carotid Angioplasties and Risk Of Stroke) is a multicenter international registry of carotid artery stenting designed to determine the criteria for identifying patients at higher or lower risk of periprocedural stroke and restenosis at 1 year. The aim of the registry is to improve patient selection and consequently reduce the risk of cerebral embolization during carotid stenting. The registry is open to all interventionists performing carotid stenting, and the participants are free to apply their own endovascular techniques and devices, including cerebral protection mechanisms. All cerebral ischemic events following the procedure will be reported. Follow-up surveillance to 1 year will include periodic duplex scanning and neurological examinations. Echographic plaque images will be standardized for comparison, processed for echodensity, and analyzed by computer at the Registry Center. Correlation will be investigated between the echographic index (gray-scale median) and the risk of embolism and outcome of carotid stenting.
Current Medical Research and Opinion, 2000
International Angiology, 2023
Centre for Cardiometabolic and Vascular Science, Department of Medicine, University College Londo... more Centre for Cardiometabolic and Vascular Science, Department of Medicine, University College London, London W1CE 6JF, U.K. Centre for Rheumatology Research and Centre for Adolescent Rheumatology Versus Arthritis, Department of Medicine, University College London, London W1CE 6JF, U.K. Scicross AB, Skövde, Sweden Vascular Screening and Diagnostic Centre, Weymouth Street, London, UK St Georges London/Nicosia Medical School, University of Nicosia, Cyprus
International angiology : a journal of the International Union of Angiology, Jun 1, 2018
Due to the evolving field of medicine, new research may, in due course, modify the recommendation... more Due to the evolving field of medicine, new research may, in due course, modify the recommendations presented in this document. At the time of publication, every attempt has been made to ensure that the information provided is up to date and accurate. It is the responsibility of the treating physician to determine the best treatment for the patient. The authors, committee members, editors, and publishers cannot be held responsible for any legal issues that may arise from the citation of this statement. Rules of evidence Management of patients with chronic venous disorders has been traditionally undertaken subjectively among physicians, often resulting in less than optimal strategies. In this document, a systematic approach has been developed with recommendations based upon cumulative evidence from the literature. Levels of evidence and grades of recommendation range from Level I and Grade A to Level III and Grade C. Level I evidence and Grade A recommendations derive from scientifically sound randomized clinical trials in which the results are clear-cut. Level II evidence and Grade B recommendations derive from clinical studies in which the results among trials often point to inconsistencies. Level III evidence and Grade C recommendations result from poorly designed trials or from small case series. 1, 2 Meta-analysis Meta-analyses are included in the present document but there should be caution as to their possible abuse. Certain studies may be included in a meta-analysis carelessly without sufficiently understanding of substantive issues, ignoring relevant variables, using heterogenous findings or interpreting results with a bias. 3 It has been demonstrated that the outcomes of 12 large randomized controlled trials were not predicted accurately 35% of the time by the meta-analyses published previously on the same topics. 4 PART I PATHOPHYSIOLOGY AND INVESTIGATION Pathophysiology Changes in superficial and deep veins Varicose veins are a common manifestation of CVD and are believed to result from abnormal dis
Surgery, 1996
This study was conducted to investigate with color flow duplex imaging the patterns and the exten... more This study was conducted to investigate with color flow duplex imaging the patterns and the extent of venous valvular incompetence in recurrent varicose vein disease. One hundred thirty-four limbs of 123 unselected patients who arrived in the outpatient clinic with residual or recurrent varicose veins after undergoing an operation were included. Limbs with history of compression sclerotherapy before or after the operation were excluded. The long (LSV) and short saphenous vein (SSV) systems in all limbs were examined with color flow duplex imaging for detection of the sites and the extent of reflux. Various patterns of recurrent valvular reflux were seen in both the LSV and SSV systems. Reflux confined to saphenofemoral junction alone or associated with reflux in the LSV system was seen in 29% of the limbs. Reflux in the whole LSV system was very common after saphenofemoral junction ligation was performed (chi-squared test, p&amp;amp;lt;0.01). Most of the limbs (53%) with recurrence in the LSV system had incompetent perforating veins. Incompetent perforators in the thigh were more common after ligation (23%) than stripping (10%), but this finding was not true in the calf. After saphenopopliteal junction ligation was performed, the more common pattern was the reflux in the SSV (75%), whereas after SSV stripping was performed, it was the reflux in the SSV tributaries (64%). Multiple patterns of reflux develop in recurrent varicose veins. Precise mapping of the reflux and identification of the possible causes are required to instigate appropriate treatment. Color flow duplex imaging is an efficient noninvasive diagnostic technique to identify venous reflux.
International angiology : a journal of the International Union of Angiology, 2008
In moderate to high-risk general surgical patients, the cost effectiveness of mechanical prophyla... more In moderate to high-risk general surgical patients, the cost effectiveness of mechanical prophylaxis for venous thromboembolism (VTE) is uncertain. Therefore, we determined the costs and savings of intermittent pneumatic compression (IPC) plus graduated compression stockings (GCS). Postoperative VTE events in the absence of prophylaxis, efficacy of prophylaxis and costs of prophylaxis have been obtained from the English literature and Medicare 2004 reimbursement schedule. In 1000 moderate to high risk general surgical patients, in the absence of prophylaxis, the cost of investigating and treating 72 patients with clinical suspicion of DVT and 32 with PE is calculated to be $263,779. This corresponds to a cost of $263 per surgical patient. The cost of IPC combined with TED stockings in 1000 similar patients would be $66 760, and the cost of diagnosis and treatment of the reduced numbers (69% reduction) of clinical VTE is $ 83,574 making a total of $150 344. This means a saving of $13...
Ultrasound and Carotid Bifurcation Atherosclerosis, 2011
ABSTRACT In the 1970s and 1980s, angiography was the standard method used for grading internal ca... more ABSTRACT In the 1970s and 1980s, angiography was the standard method used for grading internal carotid artery stenosis. With the introduction of ultrasound in the 1980s and early 1990s, angiography became the gold standard used for the development of duplex velocity criteria for different grades of stenosis.
The main criterion currently used to assess stroke risk due to atheroma of the carotid bifurcatio... more The main criterion currently used to assess stroke risk due to atheroma of the carotid bifurcation is the degree of stenosis. Although the benefit of carotid endarterectomy in stroke prevention has been demonstrated by prospective randomised trials, this benefit is moderate. Other risk factors have been suggested, such as ultrasonic carotid plaque characterisation, which may help in the identification of a high risk subgroup which will derive the maximum benefit from carotid endarterectomy. This paper reviews the literature on the clinical importance of carotid plaque characterization on histopathological and ultrasonographic grounds, and underlines the potential of objective quantitative assessment of carotid plaque echodensity in the identification of a high risk group for stroke.
Journal of Vascular Surgery, 2010
Objectives: The aim was to determine the diagnostic value of a juxtaluminal black (hypoechoic) ar... more Objectives: The aim was to determine the diagnostic value of a juxtaluminal black (hypoechoic) area without a visible echogenic cap (JBA) in ultrasonic images of internal carotid artery plaques. Methods: Ultrasonic images of plaques from 324 patients with asymptomatic (n ؍ 139) and symptomatic (n ؍ 185) internal carotid 50% to 99% stenosis in relation to the bulb (European Carotid Surgery Trial) referred for duplex scanning were studied. The JBA in mm 2 and the gray-scale median (GSM) were obtained after image normalization. Cutoff points for GSM and JBA (combined highest sensitivity with highest specificity) were determined from receiver operator characteristic (ROC) curves. Results: JBA > 8 mm 2 was associated with a high prevalence of symptomatic plaques in all grades of stenosis. In a multiple logistic regression model, increasing stenosis (mild, moderate, severe), GSM < 15 and JBA > 8 mm 2 were independent predictors of the presence of hemispheric symptoms. This model could identify a high-risk group of 188 plaques that contained 142 (77%) of the 185 symptomatic plaques (odds ratio [OR], 6.7; 95% confidence interval [CI], 4.08-10.91), (P < .001), (sensitivity: 77%; specificity 66%; positive predictive value 75%; negative predictive value 68%). Conclusions: The results of this study indicate the diagnostic value and for the first time suggest a cutoff point of 8 mm 2 for JBA. This cutoff point needs to be validated in other groups and then applied to prospective studies of asymptomatic patients.
Rheumatology, 2021
Objectives Patients with SLE have an increased risk of developing cardiovascular disease (CVD). M... more Objectives Patients with SLE have an increased risk of developing cardiovascular disease (CVD). Multiple studies have shown that these patients have increased numbers of carotid plaques and greater intima-media thickness (IMT) than healthy controls. Measures such as total plaque area (TPA) and plaque echogenicity may be more sensitive and more relevant to cardiovascular risk than presence of plaque and IMT alone. Our objective was to produce the first report of TPA and echogenicity in a population of patients with SLE. Methods One hundred patients with SLE and no history of clinical CVD were recruited. Clinical, serological and treatment variables were recorded and serum was tested for antibodies to apolipoprotein A-1 and high-density lipoprotein. Both carotid and both femoral artery bifurcations of each patient were scanned to determine IMT, TPA and echogenicity of plaques. Univariable and multivariable statistical analyses were carried out to define factors associated with each of...
Computers in Biology and Medicine, 2021
COVID-19 has infected 77.4 million people worldwide and has caused 1.7 million fatalities as of D... more COVID-19 has infected 77.4 million people worldwide and has caused 1.7 million fatalities as of December 21, 2020. The primary cause of death due to COVID-19 is Acute Respiratory Distress Syndrome (ARDS). According to the World Health Organization (WHO), people who are at least 60 years old or have comorbidities that have primarily been targeted are at the highest risk from SARS-CoV-2. Medical imaging provides a non-invasive, touch-free, and relatively safer alternative tool for diagnosis during the current ongoing pandemic. Artificial intelligence (AI) scientists are developing several intelligent computer-aided diagnosis (CAD) tools in multiple imaging modalities, i.e., lung computed tomography (CT), chest X-rays, and lung ultrasounds. These AI tools assist the pulmonary and critical care clinicians through (a) faster detection of the presence of a virus, (b) classifying pneumonia types, and (c) measuring the severity of viral damage in COVID-19-infected patients. Thus, it is of the utmost importance to fully understand the requirements of for a fast and successful, and timely lung scans analysis. This narrative review first presents the pathological layout of the lungs in the COVID-19 scenario, followed by understanding and then explains the comorbid statistical distributions in the ARDS framework. The novelty of this review is the approach to classifying the AI models as per the by school of thought (SoTs), exhibiting based on segregation of techniques and their characteristics. The study also discusses the identification of AI models and its extension from non-ARDS lungs (pre-COVID-19) to ARDS lungs (post-COVID-19). Furthermore, it also presents AI workflow considerations of for medical imaging modalities in the COVID-19 framework. Finally, clinical AI design considerations will be discussed. We conclude that the design of the current existing AI models can be improved by considering comorbidity as an independent factor. Furthermore, ARDS post-processing clinical systems must involve include (i) the clinical validation and verification of AI-models, (ii) reliability and stability criteria, and (iii) easily adaptable, and (iv) generalization assessments of AI systems for their use in pulmonary, critical care, and radiological settings.
Angiology, 2020
The objectives of this study are to (1) examine the “10-year cardiovascular risk” in the common c... more The objectives of this study are to (1) examine the “10-year cardiovascular risk” in the common carotid artery (CCA) versus carotid bulb using an integrated calculator called “AtheroEdge Composite Risk Score 2.0” (AECRS2.0) and (2) evaluate the performance of AECRS2.0 against “conventional cardiovascular risk calculators.” These objectives are met by measuring (1) image-based phenotypes and AECRS2.0 score computation and (2) performance evaluation of AECRS2.0 against 12 conventional cardiovascular risk calculators. The Asian–Indian cohort (n = 379) with type 2 diabetes mellitus (T2DM), chronic kidney disease (CKD), or hypertension were retrospectively analyzed by acquiring the 1516 carotid ultrasound scans (mean age: 55 ± 10.1 years, 67% males, ∼92% with T2DM, ∼83% with CKD [stage 1-5], and 87.5% with hypertension [stage 1-2]). The carotid bulb showed a higher 10-year cardiovascular risk compared to the CCA by 18% ( P < .0001). Patients with T2DM and/or CKD also followed a simila...
Journal of Medical Systems, 2020
This study developed an office-based cardiovascular risk calculator using a machine learning (ML)... more This study developed an office-based cardiovascular risk calculator using a machine learning (ML) algorithm that utilized a focused carotid ultrasound. The design of this study was divided into three steps. The first step involved collecting 18 officebased biomarkers consisting of six clinical risk factors (age, sex, body mass index, systolic blood pressure, diastolic blood pressure, and smoking) and 12 carotid ultrasound image-based phenotypes. The second step consisted of the design of an ML-based cardiovascular risk calculator-called "AtheroEdge Composite Risk Score 2.0" (AECRS2.0 ML) for risk stratification, considering chronic kidney disease (CKD) as the surrogate endpoint of cardiovascular disease. The last step consisted of comparing AECRS2.0 ML against the currently utilized office-based CVD calculators, namely the Framingham risk score (FRS) and the World Health Organization (WHO) risk scores. A cohort of 379 Asian-Indian patients with type-2 diabetes mellitus, hypertension, and chronic kidney disease (stage 1 to 5) were recruited for this cross-sectional study. From this retrospective cohort, 758 ultrasound scan images were acquired from the far walls of the left and right common carotid arteries [mean age = 55 ± 10.8 years, 67.28% males, 91.82% diabetic, 86.54% hypertensive, and 83.11% with CKD]. The mean office-based cardiovascular risk estimates using FRS and WHO calculators were 26% and 19%, respectively. AECRS2.0 ML demonstrated a better risk stratification ability having a higher area-under-the-curve against FRS and WHO by~30% (0.871 vs. 0.669) and2 0% (0.871 vs. 0.727), respectively. The office-based machine-learning cardiovascular risk-stratification tool (AECRS2.0 ML) shows superior performance compared to currently available conventional cardiovascular risk calculators.
Computer methods and programs in biomedicine, 2018
Accurate, reliable, efficient, and precise measurements of the lumen geometry of the common carot... more Accurate, reliable, efficient, and precise measurements of the lumen geometry of the common carotid artery (CCA) are important for (a) managing the progression/regression of atherosclerotic build-up and (b) the risk of stroke. The image-based degree of stenosis in the carotid artery and the plaque burden can be predicted using the automated carotid lumen diameter (LD)/inter-adventitial diameter (IAD) measurements from B-mode ultrasound images. The objective of this review is to present the state-of-the-art methods and systems for the measurement of LD/IAD in CCA based on automated or semi-automated strategies. Further, the performance of these systems is compared based on various metrics for its measurements. The automated algorithms proposed for the segmentation of carotid lumen are broadly classified into two different categories as: region-based and boundary-based. These techniques are discussed in detail specifying their pros and cons. Further, we discuss the challenges encounte...
Journal for Vascular Ultrasound, 2018
Currently, carotid intima-media thickness (cIMT) and geometric total plaque area (gTPA) are compu... more Currently, carotid intima-media thickness (cIMT) and geometric total plaque area (gTPA) are computed manually and thus are tedious and prone to interobserver and intraobserver variabilities. This study presents an intelligence-based automated deep learning (DL)–based technique for carotid wall interface detection, cIMT, and lumen diameter (LD) measurements, followed by a 3D cylindrical approach for TPA measurement. The observers were used for manual tracings of which were then used for the design of two DL-based systems. The DL boundaries for inner lumen wall and outer interadventitial borders were used for computing the cIMT and LD. Using cylindrical approach, we computed the gTPA. Furthermore, we compute the 10-year image-based cIMT and gTPA, using the progression rates. A total of 396 B-mode ultrasound right and left common carotid artery images were taken from 203 patients. The mean cIMT and gTPA using DL1 and DL2 is 0.91 mm, 20.52 mm2 and 0.88 mm, 19.44 mm2, respectively. The c...
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Papers by Andrew Nicolaides