Multiscale - Patient-Specific Artery and Atherogenesis Models

In this work, we present a platform for the development of multiscale patient-specific artery and atherogenesis models. The platform, called ARTool, integrates technologies of 3-D image reconstruction from various image modalities, blood flow and biological models of mass transfer, plaque characterization, and plaque growth. Patient images are acquired for the development of the 3-D model of the patient specific arteries. Then, blood flow ismodeled within the arterial models for the calculation of the wall shear stress distribution (WSS). WSS is combined with other patient-specific parameters for the development of the plaque progression models. Real-time simulation can be performed for same cases in grid environment. The platform is evaluated using both animal and human data

Patient-specific simulation of coronary artery pressure measurements: An in vivo three-dimensional validation study in humans

Copyrigh

Panvascular disease – Diagnosis and management

Panvascular disease (PVD) increases significantly the risk for cardiovascular events (myocardial infarction, stroke and cardiovascular death); the more sites affected, the greater the risk of a major cardiac event. Despite its high incidence and severe cardiovascular prognosis, PVD has still not been well studied. History of risk factors and co-morbidities, as well as a detailed physical examination, are mandatory in the initial screening and diagnostic work-up. The ankle-brachial index and various non-invasive imaging methods such as duplex ultrasound, computed tomography or magnetic resonance angiography are used for the diagnosis of atherosclerosis in various vascular beds, while digital subtraction angiography is currently used almost exclusively in association with endovascular procedures. Appropriate utilization of techniques is based on international guidelines and a multidisciplinary discussion for each case. Management of a patient diagnosed with PVD can be very complex. Secondary preventive measures and aggressive medical treatment are needed to reduce excess cardiovascular risk. Whether routine screening for atherosclerosis at various sites in the arterial tree in all or selected patients may alter treatment to improve outcome in these patients has not been shown. In the lack of hard evidence, individualized decision-making is needed with the collaboration of many specialties in a multidisciplinary approach. In general, the more symptomatic lesion or the lesion with the strongest prognostic impact should be treated first. In selected cases combined interventions can be done. Perioperative cardiovascular complications are common in patients with PVD, thus preoperative targeted screening may be needed. Clinical studies are needed to identify more effective approaches to diagnose and treat these patients. A single trial performed so far failed to demonstrate a panvascular screening in patients with severe coronary artery disease. Meanwhile, a multidisciplinary team is often needed to optimize short- and long-term prognosis. © 201

Effect of the insulin sensitizers metformin and pioglitazone on endothelial function in young women with polycystic ovary syndrome: A prospective randomized study

Objective: To compare the effect of two different insulin sensitizers, metformin and pioglitazone, on endothelial function in women with polycystic ovary syndrome (PCOS). Design: Prospective randomized study. Setting: University Hospital endocrinology outpatient clinic. Patient(s): Young women with PCOS (aged 23.3 ± 4.9 years). Intervention(s): Patients were assigned randomly to no treatment (n = 14), metformin 850 mg two times per day (n = 15), and pioglitazone 30 mg daily (n = 14) for 6 months. Healthy age- and body mass index-matched women served as controls (n = 14). Main Outcome Measure(s): Brachial artery flow-mediated dilation was studied at baseline and 6 months. Result(s): Women with PCOS had higher insulin resistance and hyperandrogenism indices and lower flow-mediated dilation compared with controls. The three groups of women with PCOS did not differ at baseline. No differences were observed at follow-up in women who received no treatment. Metformin and pioglitazone improved flow-mediated dilation to a similar extent, restoring it to normal values at 6 months. Both insulin sensitizers induced favorable changes in insulin resistance and hyperandrogenism indices in women with PCOS. Independent predictors of flow-mediated dilation improvement at 6 months were treatment with insulin sensitizers and reduction in insulin resistance. Conclusion(s): In young women with PCOS, treatment with metformin or pioglitazone for 6 months induces a similar beneficial effect on endothelial function; this may be partially attributed to an improvement in insulin resistance. Further research is needed to investigate whether treatment with insulin sensitizers in women with PCOS also reduces cardiovascular risk. © 2011 American Society for Reproductive Medicine, Published by Elsevier Inc

Remote sensing natural time analysis of heartbeat data by means of a portable photoplethysmography device

Very recent work reported that patients can monitor their heartbeat at home and specify their heart conditions by means of a millimetre wave radar, but there exist serious limitations because the radar sensor is sensitive to significant body motions that cause Doppler frequency shifts. Such limitations do not exist when using a recently constructed portable photoplethysmography (PPG) electronic device, which gives results comparable with a standard electrocardiogram (ECG). Since all portable modern devices such as smart phones tablets etc support Bluetooth communication that allows easy and direct communication with our PPG device, it may give us remote sensing heart related information. Applying natural time analysis to data simultaneously collected with an ECG system and a PPG device and using two complexity measures quantifying the entropy change in natural time under time reversal, a distinction is achieved between healthy (H) individuals and congestive heart failure (CHF) patients. Employing a support vector machine classifier for CHF discrimination to a total of 99 individuals (including 67 CHF), we obtained 97.7% sensitivity. In a follow up study challenging results are obtained since during the subsequent period six individuals died, who remarkably obeyed additional complexity measures that may distinguish sudden cardiac death individuals from CHF. © 2020 Informa UK Limited, trading as Taylor & Francis Group

A prototype photoplethysmography electronic device that distinguishes congestive heart failure from healthy individuals by applying natural time analysis

In this paper, a prototype photoplethysmography (PPG) electronic device is presented for the distinction of individuals with congestive heart failure (CHF) from the healthy (H) by applying the concept of Natural Time Analysis (NTA). Data were collected simultaneously with a conventional three-electrode electrocardiography (ECG) system and our prototype PPG electronic device from H and CHF volunteers at the 2nd Department of Cardiology, Medical School of Ioannina, Greece. Statistical analysis of the results show a clear separation of CHF from H subjects by means of NTA for both the conventional ECG system and our PPG prototype system, with a clearly better distinction for the second one which additionally inherits the advantages of a low-cost portable device. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Association of QRS narrowing with response to cardiac resynchronization therapy—a systematic review and meta-analysis of observational studies

Prolonged QRS duration, which reflects a higher degree of mechanical dysynchrony, is a predictor of response to CRT. However, the association of QRS narrowing after biventricular pacing with CRT response rates is not clear. Our aim was to conduct a systematic review and meta-analysis on the association between QRS narrowing after cardiac resynchronization therapy (CRT) and clinical and echocardiographic response to CRT in patients with heart failure. Two independent investigators searched MedLine and EMBASE databases through July 2018 without any limitations. Studies providing estimates (continuous data) on the association of QRS shortening with either clinical (defined as New York Heart Association (NYHA) reduction ≥ 1) or echocardiographic (defined as left ventricular end-systolic volume (LVESV) reduction ≥ 15%) response to CRT were finally included in the quantitative synthesis. We included 32 studies (14 studies (1274 patients mean age 64 years old, males 79.3%) using clinical CRT response and 18 studies (1270 patients, mean age 64 years old, males 69.1%) using echocardiographic CRT response). A significant association between QRS narrowing and shorter attained QRS duration with clinical and echocardiographic CRT response was observed. The observed association was independent of the timing of QRS width measurement after CRT implantation. Acute and late improvement of electrical dysynchrony as depicted by QRS narrowing following biventricular pacing is associated with clinical and echocardiographic response to CRT. However, large prospective studies are needed to further examine our findings. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

Impact of ranolazine on ventricular arrhythmias – a systematic review

Ranolazine is a new medication for the treatment of refractory angina. However, except its anti-anginal properties, it has been found to act as an anti-arrhythmic. The aim of our systematic review is to present the existing data about the impact of ranolazine in ventricular arrhythmias. We searched MEDLINE and Cochrane databases as well clinicaltrials.gov until September 1, 2017 to find all studies (clinical trials, observational studies, case reports/series) reported data about the impact of ranolazine in ventricular arrhythmias. Our search revealed 14 studies (3 clinical trials, 2 observational studies, 8 case reports, 1 case series). These data reported a beneficial impact of ranolazine in ventricular tachycardia/fibrillation, premature ventricular beats, and ICD interventions in different clinical settings. The existing data highlight the anti-arrhythmic properties of ranolazine in ventricular arrhythmias. © 2018 The Authors

Patient-specific computational modeling of subendothelial LDL accumulation in a stenosed right coronary artery: Effect of hemodynamic and biological factors

Atherosclerosis is a systemic disease with local manifestations. Low-density lipoprotein (LDL) accumulation in the subendothelial layer is one of the hallmarks of atherosclerosis onset and ignites plaque development and progression. Blood flow-induced endothelial shear stress (ESS) is causally related to the heterogenic distribution of atherosclerotic lesions and critically affects LDL deposition in the vessel wall. In this work we modeled blood flow and LDL transport in the coronary arterial wall and investigated the influence of several hemodynamic and biological factors that may regulate LDL accumulation. We used a three-dimensional model of a stenosed right coronary artery reconstructed from angiographic and intravascular ultrasound patient data. We also reconstructed a second model after restoring the patency of the stenosed lumen to its nondiseased state to assess the effect of the stenosis on LDL accumulation. Furthermore, we implemented a new model for LDL penetration across the endothelial membrane, assuming that endothelial permeability depends on the local lumen LDL concentration. The results showed that the presence of the stenosis had a dramatic effect on the local ESS distribution and LDL accumulation along the artery, and areas of increased LDL accumulation were observed in the downstream region where flow recirculation and low ESS were present. Of the studied factors influencing LDL accumulation, 1) hypertension, 2) increased endothelial permeability (a surrogate of endothelial dysfunction), and 3) increased serum LDL levels, especially when the new model of variable endothelial permeability was applied, had the largest effects, thereby supporting their role as major cardiovascular risk factors