REVIEW | doi:10.20944/preprints202304.1112.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: pulmonary stenosis; aortic stenosis; aortic coarctation; balloon valvuloplasty; balloon angioplasty; infundibular stenosis; right ventricular filling; aortic remodeling
Online: 28 April 2023 (04:48:14 CEST)
While investigating the outcomes of balloon dilatation procedures in patients with congenital obstructive lesions of the heart, several parallel observations have been made. The purpose of this review is to present these observations/phenomena/innovations related to balloon dilatation of pulmonary stenosis (PS), aortic stenosis (AS), and aortic coarctation (AC). In subjects who had balloon pulmonary valvuloplasty (BPV), development of infundibular obstruction, electrocardiographic (ECG) changes, changes in right ventricular filling, role of balloon/annulus ratios on the results of BPV, and double balloon vs. single balloon BPV will be reviewed. In patients who had balloon aortic valvuloplasty (BAV), causes of aortic insufficiency and trans-umbilical venous approach for BAV will be tackled. In children who had balloon angioplasty (BA) of AC, aortic remodeling and biophysical response after BA of AC will be discussed.
CASE REPORT | doi:10.20944/preprints202307.0460.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: Osteopetrosis; Pyloric stenosis; Familial
Online: 7 July 2023 (05:10:19 CEST)
Osteopetrosis incidence is less than 1:200,000 birth in most populations (Worth, 1963) . It's more common in consanguineous people as it's unusual in two members of the same family. The defined treatment for Osteopetrosis is Hematopoietic stem cell transplantation (HSCT). With a 73% five years disease-free survival in donors. The incidence of Hypertrophic pyloric stenosis is 1 in 300–900 newborns. Hypertrophic pyloric stenosis is due to hypertrophy of the smooth muscle of the pyloric sphincter. The classic age of occurrence is the first few months of life, and the classic presentation is non-bilious projectile vomiting after feeding. We reported a four family members with Osteopetrosis and Pyloric stenosis and their three cousins with Osteopetrosis, which is a very rare presentation and association.
REVIEW | doi:10.20944/preprints202305.0209.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: diagnosis; secondary prevention; complications; abdominal aortic aneurysm; carotid stenosis; lower extremity arterial disease; popliteal artery aneurysm; renal artery stenosis; subclavian artery stenosis
Online: 4 May 2023 (07:21:59 CEST)
Middle-aged adults can start to be affected by some arterial diseases, such as abdominal aortic or popliteal artery aneurysms, lower extremity arterial disease, internal carotid or renal artery or subclavian artery stenosis. These vasculopathies are often paucisymptomatic before manifesting themselves with dramatic complications. Therefore, early detection of peripheral artery disease (PAD) and aneurysmal disease is fundamental to reduce the risk of major adverse cardiovascular and limb events. Furthermore, PAD carries a high correlation with silent coronary artery disease (CAD). This study focuses on the most common PADs and aneurysmal diseases, in the attempt to summarize some key points which should selectively drive screen. Since it is evident how we are not in the human and economic possibilities to instrumentally screening wide populations, deep knowledge of semeiotics and careful anamnesis must play a central role in our daily activity as physician. The presence of some risk factors for atherosclerosis, or an already known history of CAD, can raise the clinical suspecion of PAD or aneurysmal disease after a careful clinical history and a deep physical examination. The clinical suspicion must then be confirmed by a first-level ultrasound investigation and, if so, adequate treatments can be adopted to prevent dreadful complications.
ARTICLE | doi:10.20944/preprints202307.1540.v1
Subject: Medicine And Pharmacology, Veterinary Medicine Keywords: Congenital; Colonic Agenesis; Stenosis; Canine; Feline
Online: 24 July 2023 (09:30:00 CEST)
Congenital diseases of the large intestine have scarcely been reported and mostly include fistula, atresia, or colonic duplication. Cases of partial colonic agenesis have rarely been described. The purpose of this study was to report a cohort of dogs and cats diagnosed with partial colonic agenesis. The colon was measured during colonoscopy or contrast-radiography and compared to the average length described in the literature. Six dogs and 17 cats were retrospectively included. Depending on the case, partial colonic agenesis could represent an incidental finding or the likeliest cause of clinical signs. Diarrhea was reported in most cases, and no specific clinical or biological abnormality was observed. Median age of presentation was variable and long asymptomatic periods were common. Abdominal ultrasound was useful and identified a short colon in 14/17 cats but only in one dog. Endoscopy was useful to confirm the diagnosis and to identify associated lesions and complications. Among others, colonic stenosis was reported in 8/9 cases that had lifelong clinical signs and the shortest colon length. This anatomical abnormality could promote chronic inflammation that might generate fibrosis and ultimately stenosis.
REVIEW | doi:10.20944/preprints202107.0384.v2
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: miRNAs; valvular heart diseases; aortic stenosis; calcification; mitral valve prolapse, aortic valve defect; vectors; delivery systems; nanoparticles
Online: 8 November 2021 (14:25:40 CET)
miRNAs have recently attracted investigators' interest as regulators of valvular diseases pathogenesis, diagnostic biomarkers, and therapeutical targets. Evidence from in-vivo and in-vitro studies demonstrated stimulatory or inhibitory roles in mitral valve prolapse development, aortic leaflet fusion, and calcification pathways, specifically osteoblastic differentiation and transcription factors modulation. Tissue expression assessment and comparison between physiological and pathological phenotypes of different disease entities, including mitral valve prolapse and mitral chordae tendineae rupture, emerged as the best strategies to address miRNAs over or under-representation and thus, their impact on pathogeneses. In this review, we discuss the fundamental intra- and intercellular signals regulated by miRNAs leading to defects in mitral and aortic valves, congenital heart diseases, and the possible therapeutic strategies targeting them. These miRNAs inhibitors comprise of antisense oligonucleotides and sponge vectors. The miRNA mimics, miRNA expression vectors, and small molecules are instead possible practical strategies to increase specific miRNA activity. Advantages and technical limitations of these new drugs, including instability and complex pharmacokinetics, are also presented. Novel delivery strategies, such as nanoparticles and liposomes, are described to improve knowledge on future personalized treatment directions.
ARTICLE | doi:10.20944/preprints202301.0276.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: FFR; Blood Flow Simulation; SimVascular; coronal stenosis; cCTA
Online: 16 January 2023 (08:29:37 CET)
A novel physiologically based algorithm (PBA) for fast CFD computation of Flow Fractional Reserve (FFR) in Coronary Artery Trees (CATs) is proposed and developed, which, unlike traditional methods, is based on the extension of the Murray’s law for blood vessels at the outlets and extra inlet conditions prescribed alternatively and iteratively. The PBA is then implemented in both SimVascular and Ansys CFD for testing and validation. For validation purpose, 3D models of CATs are built by using their CT images and computational meshes generated for mesh convergence study. Results obtained are then compared with Invasive Coronary Angiographic (ICA) data for validation and evaluation of its accuracy and computational efficiency. It is found that discrepancies between experimental and calculated values of pressure and flow rate at the inlet were less than 0.1% at the end of the 10th round of iteration or less. Further validation shows that the difference between estimated and experimental FFR agree with each other with a maximum difference of 1.62% after convergence is achieved. The PBA is found to be a robust patient-specific and physiologically sound method that can be a good alternative to the existing Lumped Parameter Model (LPM) which is based on empirical scaling correlations using limited population-averaged data and requires nonlinear iterative computation for convergence.
ARTICLE | doi:10.20944/preprints202309.0376.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: Cervical spine; dynamic MRI; foraminal stenosis; kinetic MRI; Spurling test
Online: 6 September 2023 (14:31:16 CEST)
Diagnosing cervical foraminal stenosis with intermittent arm radiculopathy is chal-lenging due to discrepancies between MRI findings and symptoms. This can be attributed to the fact that MRI images are often obtained in a relaxed supine position. This study aims to evaluate the feasibility of the Dynamic MRI Compression System (DMRICS) and to assess possible changes in cervical foramina, with both quantitative measurements and qualitative grading systems, with MRI during a simulated Spurling test. Ten patients (5 women and 5 men, ages 29-45) with previously confirmed cervical foraminal stenosis underwent MRI scans using DMRICS. MRIs were acquired in both relaxed and provoked states. A radiologist assessed 30 foramina (C4-C7) on the symptomatic side in both patient positions. Quantitative and qualitative measures were performed including the Numeric Rating Scale (NRS) and the Park and Kim grading systems. The provoked state induced concordant neck and arm pain in 9 of 10 patients. Significant shifts in Park and Kim fo-raminal gradings were noted: 13 of 27 Park gradings and 9 of 27 Kim gradings escalated post-provocation. No quantitative changes were observed. This pilot study indicates that the DMRICS device has potential to improve diagnostic accuracy for cervical radicu-lopathy, demonstrating induced cervical foraminal changes during a simulated Spurling test while performing MRI.
ARTICLE | doi:10.20944/preprints202307.1588.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: bicuspid aortic valve; computed tomography; aortic regurgitation; aortic stenosis; aortopathy
Online: 24 July 2023 (10:47:53 CEST)
(1) Background: To identify the association between the presence or absence of raphe and aortic valve dysfunction as well as the presence of aortopathy in patients with bicuspid aortic valve (BAV); (2) Methods: This retrospective study enrolled 312 participants (mean [SD] age, 52.7 [14.3] years; 227 men [72.8%]) with BAV. The BAVs were divided into those with presence (raphe+) or absence (raphe-) of raphe. Valvular function was classified as normal, aortic regurgitation (AR), or aortic stenosis (AS) using TTE. The pattern of BAV aortopathy was determined by the presence of dilatation at the sinus of Valsalva and the middle ascending aorta using CCT.; (3) Results: BAVs with raphe+ had a higher prevalence of AR (148 [79.5%] vs. 48 [37.8%], P < .001) but a lower prevalence of AS (90 [48.6%] vs. 99 [78.0%], P < .001) compared with those with raphe-. The types of BAV aortopathy were significantly different (P = 0.021) according to those with BAV-raphe+ and BAV-raphe-.; (4) Conclusions: The presence of a raphe was significantly associated with a higher prevalence of AR but a lower prevalence of AS and combined dilatation of the aortic root and middle ascending aorta. The presence of raphe was an independent determinant of AR.
REVIEW | doi:10.20944/preprints202306.1863.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: atherosclerosis; stroke; carotid; stenosis; biomarker; plaque; lipid; inflammation; IL-6
Online: 27 June 2023 (11:00:33 CEST)
Intracranial and extracranial large artery atherosclerosis (LAA) are a main cause of ischemic stroke. Biomarkers may aid in the diagnosis of LAA and help to stratify patients´ risk of stroke. We performed a narrative review of the literature mainly published in the last five years with the aim of identifying biomarkers associated either with intracranial or extracranial LAA in humans. Several potential biomarkers of LAA mainly related to lipid pathways and inflammation have been studied. Diagnostic biomarkers of LAA were evaluated by measuring biomarkers levels in patients with LAA stroke and other stroke etiologies. Some biomarkers were associated with prognosis of LAA stroke as evaluated by the modified Rankin score. Increased levels of IL-6 and have been associated with the risk of progression of the atherosclerotic disease. Overall, in most studies, the results were not externally validated. External validation of these results is needed. In the future, biomarkers could be useful for the selection of patients for clinical trials. To adopt these biomarkers in clinical practice we will need robust multicentric studies proving their reproduci-bility and a clear practical applicability for their use.
ARTICLE | doi:10.20944/preprints202306.0550.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: Global sagittal balance; Transforaminal epidural steroids injections; Lumbar spinal stenosis
Online: 7 June 2023 (12:10:35 CEST)
Patients' functional adaptation to pain can affect global sagittal alignment. This study evaluated the short-term spinal sagittal alignment change after Transforaminal Epidural Steroid Injection (TFESI) in lumbar spinal stenosis patients. Patients with lumbar spinal stenosis who underwent TFESI were retrospectively examined. Clinical outcomes were Visual Analog Scale (VAS) and Oswestry Disability Index (ODI). Before and two weeks after the intervention, whole spine lateral standing view radiographs were taken. Radiographic parameters, e.g., Sagittal Vertical Axis (SVA), C2C7 Cobb, Thoracic Kyphosis (TK), Lumbar Lordosis (LL), Pelvic Incidence (PI), Pelvic Tilt (PT), Sacral Slope (SS), and Lumbopelvic Mismatch (PI-LL), were measured. Ninety-nine patients (mean age 64.3 ± 9.2 years) were included in this study. Both VAS and ODI outcomes were statistically improved after two weeks of intervention. Radiographic parameters showed that SVA, PT, and PI-LL mismatch were significantly decreased, while C2C7 Cobb, TK, SS, and LL were significantly increased after the intervention. SVA was improved by 29.81% (52.76 ± 52.22 mm to 37.03 ± 41.07 mm, P < 0.001). PT was also decreased significantly from 28.71° ± 10.22° to 23.84° ± 9.96° (P < 0.001). Transforaminal Epidural Steroid Injection (TFESI) significantly improves VAS, ODI, and global sagittal parameters in lumbar spinal stenosis patients.
ARTICLE | doi:10.20944/preprints202303.0127.v1
Subject: Computer Science And Mathematics, Applied Mathematics Keywords: inite element method; Stenosis; Bifurcation; Wall shear stress; Elastic walls
Online: 7 March 2023 (07:32:27 CET)
The buildup of plaque in the arteries characterizes atherosclerosis, which causes the walls of the arteries to thicken, the lumen to narrow, and the wall to thin in certain areas. These changes can lead to alterations in blood flow, potentially resulting in aneurysms and heart attacks if left untreated. This paper presents a phenomenological model to explain the mechanics of plaque rupture in stenosed bifurcated elastic arteries. The model considers the interaction between the plaque and artery wall, blood flow, mechanical properties of the artery wall and plaque, and hemodynamic forces in the system. Using the Navier-Stokes equations to describe blood flow and elastic properties of artery walls, our study shows that blood flow can become turbulent, leading to backflow, vortices, and possible stagnation. Certain regions can become highly vulnerable and result in elevated heat transfer between blood and arterial walls, which can lead to the rupture of the plaque cap. The study focuses on blood flow features such as velocity profiles and wall displacement on fluid-structure interaction, which are consistent with the literature. Finally, we calculate the wall shear stress (WSS) for minimum and maximum times while considering elastic walls. Our findings may provide valuable insights into the mechanisms of plaque rupture and inform the development of improved diagnostic and therapeutic approaches.
CASE REPORT | doi:10.20944/preprints202309.0091.v1
Subject: Medicine And Pharmacology, Pulmonary And Respiratory Medicine Keywords: idiopathic pulmonary arterial hypertension; epoprostenol; prostaglandin I₂; giant goiter; airway stenosis
Online: 5 September 2023 (10:28:08 CEST)
It has been reported that prostaglandin I2, such as epoprostenol, develops Grave's disease. A 34-year-old woman was diagnosed with idiopathic pulmonary arterial hypertension and started receiving continuous intravenous epoprostenol. Three years after starting epoprostenol, she started complaining of neck swelling and was diagnosed with Grave’s disease. Thyroid function was controlled by thiamazole and levothyroxine. Nevertheless, her thyroid gland enlargement worsened as epoprostenol dose was titrated. After 23 years of treatment with epoprostenol, she suddenly experienced respiratory failure with a giant goiter leading to airway stenosis and passed away. The autopsy confirmed a giant goiter associated with hyperthyroidism and airway stenosis. We experienced a case of idiopathic pulmonary hypertension with a giant goiter and airway stenosis after long-term intravenous epoprostenol therapy.
REVIEW | doi:10.20944/preprints202308.0404.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: aortic stenosis, cancer, valve replacement, cardio-oncology, transcatheter valve implantation, radiation therapy
Online: 4 August 2023 (11:44:10 CEST)
Aortic valve stenosis and malignancy frequently coexist and share the same risk factors as atherosclerotic disease. Data reporting the prognosis of patients with severe aortic stenosis and cancer are limited. Tailoring the correct and most optimal care for cancer patients with severe aortic stenosis is complex. Cancer patients may be further disadvantaged by aortic stenosis if it interferes with their treatment by increasing the risk associated with oncologic surgery and compounding the risks associated with cardiotoxicity and heart failure (HF). Nowadays, several therapeutic options are available for aortic valve stenosis (surgical valve replacement , transcatheter valve implantation, balloon valvuloplasty, or medical therapy), but in presence of malignancy, the use of one of these versus the others should be decided on a case-by-case approach, depending on cancer stage and associated treatment, expected outcome, comorbidities and after an accurate physical examination and Doppler-echocardiography which are the key tools for diagnosing and evaluating aortic stenosis. The current review considers the available data on the association between aortic stenosis and cancer, and therapeutic options.
ARTICLE | doi:10.20944/preprints202305.2019.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: aortic stenosis; transcatheter aortic valve replacement; age; surgical risk; low-intermediate risk
Online: 29 May 2023 (14:36:38 CEST)
Background: Current European guidelines support transcatheter aortic valve implantation (TA-VI) in intermediate to low-risk patients ≥75 years-old but its prognostic relevance is unknown. Methods: Intermediate-to-low-risk (Society of Thoracic Surgeon score <8%) patients enrolled in the HORSE registry were included. We compared the population with less versus more than 75 years old. The primary endpoint was all-cause mortality. Results: A total of 2685 patients were included, 280 (8.6%) <75 and 2405 ≥75 years. Through a mean follow-up of 437 ± 381 days, 198 (8.2%) and 23 (8.2%) patients died in the two arms, without statistically significant differences (log-rank p=0.925). At Cox regression analysis, age did not predict the occurrence of all-cause death, neither as a continuous variable (HR 1.01, 95% CI 0.99-1.04, p=0.294) nor dichotomizing according to the prespecified cutoff of 75 years (HR 0.97, 95% CI 0.63-1.51p=0.924). Time-to-event ROC curves showed low accuracy of age to predict all-cause mortality (area under the curve of 0.54 for both 1-year and 2-year outcomes). Conclusions: TAVI has comparable benefits across age strata in intermediate-to-low risk patients. The age cut-off suggested by current guidelines is not predictive of the risk of adverse events during hospital stay, neither of all-cause mortality through a mid-term follow-up.
ARTICLE | doi:10.20944/preprints202301.0201.v1
Subject: Biology And Life Sciences, Biophysics Keywords: FFR, Blood Flow Simulation, coronal stenosis, Coronary Computed Tomography Angiography (CCTA), OpenFOAM
Online: 11 January 2023 (11:56:16 CET)
A novel physiologically based algorithm (PBA) for the computation of fractional flow reserve (FFR) in coronary artery trees (CATs) using computational fluid dynamics (CFD) is proposed and developed. The PBA is based on the extension of Murray's law and additional inlet conditions prescribed iteratively, and is implemented in OpenFOAM for testing and validation. 3D models of CATs are created using CT scans and computational meshes, and the results are compared to in-vasive coronary angiographic (ICA) data to validate the accuracy and effectiveness of the PBA. The discrepancy between calculated and experimental FFR is within 2.33-5.26% in steady-state and transient simulations, respectively, when convergence is reached. The PBA is a reliable and physiologically sound technique compared to the current lumped parameter model (LPM), which is based on empirical scaling correlations and requires nonlinear iterative computing for conver-gence. The accuracy of the PBA method is further confirmed using the FDA nozzle, which demonstrates good alignment with CFD-validated values.
ARTICLE | doi:10.20944/preprints202309.0921.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Atherogenic Index of Plasma; Coronary artery disease; Cardiovascular risk factor; Coronary artery stenosis
Online: 13 September 2023 (15:49:51 CEST)
Aims: Chronic coronary syndrome is associated with several risk factors, such as dyslipidemia and hypertension. AIP has been demonstrated to be a biochemical risk factor for coronary artery disease (CAD). This study aimed to determine whether AIP is an effective parameter for estimating obstructive CAD. Methods and Results: A total of 345 patients (mean age 62,2±10,3; 63% male) who underwent coronary angiography were included in this study. Obstructive CAD is defined as having one or more vessels with a stenosis of≥50%. Depending on the presence of obstructive CAD, all patients were divided into two groups. The AIP was significantly higher in the obstructive coronary artery group (AIP; 0,49±0,26 vs. 0,58±0,27, p=0,002). In univariate analysis, AIP was significantly associated with obstructive coronary artery disease [OD:3,74 (CI95% 1,62-8,64), P=0,020]. The AIP was further adjusted for confounding risk factors in three multivariate analysis models. Therefore, all three models showed a significant association. According to ROC analysis, 0.49 is the cut-off value for AIP, and a value above 0.49 indicates 50% coronary artery stenosis Conclusions: AIP may be used in the assessment of cardiovascular risk in patients with stable angina pectoris, and it may also be used to estimate obstructive CAD.
ARTICLE | doi:10.20944/preprints202306.0310.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: exercise training; aortic stenosis; heart failure; isolated papillary muscle; isolated cardiomyocyte; calcium handling.
Online: 5 June 2023 (10:47:28 CEST)
Aerobic exercise training (AET) has been used in the management of heart disease. AET may, totally or partially, restore the activity and/or expression of proteins that regulate calcium (Ca2+) handling, optimize intracellular Ca2+ flow, and attenuate cardiac functional impairment in failing hearts. However, the literature presents conflicting data regarding the effects of AET on Ca2+ transit and cardiac function in rats with heart failure resulting from aortic stenosis. The objective of this study was to evaluate the effects of AET on calcium handling and cardiac function in rats with heart failure due to aortic stenosis. Wistar rats were distributed into two groups: control (Sham; n= 61) and aortic stenosis (AoS; n= 44). After 18 weeks, the groups were redistributed into: non-exposed to exercise training (Sham, n = 28 and AoS, n = 22) and trained (Sham-ET, n = 33 and AoS-ET, n = 22) for 10 weeks. Treadmill exercise training was performed with a velocity equivalent to the lactate threshold. Echocardiogram, isolated papillary muscle, and isolated cardiomyocyte analyzed cardiac function. During isolated papillary muscle assay and isolated cardimyocyte was evaluated Ca2+. The expression of regulatory proteins of diastolic Ca2+ was analyzed via Western Blot. AET attenuated the diastolic dysfunction and benefited the systolic function. AoS-ET animals presented better response to post-rest contraction, and SERCA2a and L-type Ca2+ channels blocked than the AoS. Furthermore, AET was able to improve aspects of the mechanical function and the responsiveness of the myofilaments to the Ca2+ of the AoS-ET animals. AoS animals presented alteration in the protein expression of the SERCA2a and NCX, and AET restored SERCA2a and NCX levels near normal values. Therefore, AET increased SERCA2a activity, improved the cellular Ca2+ influx mechanism, and increased myofilament responsiveness to Ca2+, attenuating cardiac dysfunction at cellular, tissue, and chamber levels in animals with aortic stenosis and heart failure.
ARTICLE | doi:10.20944/preprints202303.0117.v1
Subject: Computer Science And Mathematics, Computational Mathematics Keywords: Bifurcation; Elastic walls; Finite element method; Stenosis; Wall shear stress; Mag-netic field
Online: 7 March 2023 (02:03:46 CET)
To investigate the impact of a magnetic field on plaque development in a stenotic bifurcated artery, a finite element method is utilized. The blood flow is modelled as a stable, incompressible, Newtonian, biomagnetic, and laminar fluid. Furthermore, the arterial wall is assumed to be linear elastic. The Arbitrary Lagrangian Eulerian (ALE) method is employed to describe the hemodynamic flow in a bifurcated artery under the influence of an asymmetric magnetic field, taking into account two-way fluid-structure interaction coupling. A stable $P_2P_1$ finite element pair discretizes a nonlinear system of partial differential equations that requires a solution. The Newton-Raphson method is utilized to find a solution to the resulting nonlinear algebraic equation system. Numerical modelling is used to simulate the presence of magnetic fields, and the resulting displacement, velocity magnitude, pressure, and wall shear stresses are shown for a range of Reynolds numbers ($Re = 500$, $1000$, $1500$, and $2000$). The results of the numerical analysis demonstrate that the presence of a magnetic field has a significant effect not only on the magnitude of displacement but also on the velocity of the flow. The application of a magnetic field reduces flow separation, extends the recirculation area near the stenosis, and increases wall shear stress.
REVIEW | doi:10.20944/preprints202112.0465.v1
Subject: Medicine And Pharmacology, Surgery Keywords: Anal stenosis; hemorrhoidectomy; diamond flap; house advancement flap; rhomboid flap; Y-V flap
Online: 29 December 2021 (12:18:26 CET)
Anal stenosis, which develops as a result of aggressive excisional hemorrhoidectomy, especially with the stoutly use of advanced technologies (LigaSure, Ultrasonic Dissector, Laser, etc.), has become common, causing significant deterioration in the patient's quality of life. Although non-surgical treatment is effective for mild anal stenosis, surgical reconstruction is unavoidable for moderate to severe anal stenosis that causes distressing, severe anal pain, and inability to defecate. The problem in anal stenosis, unlike anal fissure, is that the skin does not stretch as a result of chronic fibrosis due to surgery. Therefore, the application of lateral internal sphincterotomy does not provide satisfactory results in the treatment of anal stenosis. Surgical treatment methods are based on the use of flaps of different shapes and sizes to reconstruct the anal caliber and flexibility. This article aims to review the functional results, postoperative care, and complications of these methods.
ARTICLE | doi:10.20944/preprints202108.0026.v1
Subject: Computer Science And Mathematics, Algebra And Number Theory Keywords: 1D haemodynamics, stenosis, systole variations, coronary circulation, tachycardia, boundary conditions, FFR, CFR, iFR.
Online: 2 August 2021 (12:08:24 CEST)
Haemodynamic indices are widely used in clinical practice for deciding on a particular type of treatment. Low quality of the CT data and tachycardia complicate interpretation of the measured or simulated values. In this work, we present a novel approach for evaluating resistances in terminal coronary arteries. Using 14 measurements from 10 patients, we show that this algorithm retains the accuracy of 1D haemodynamic simulations in less detailed (truncated) geometric models of coronary networks. We also apply the variable systole fraction model to study the effect of elevated heart rate on the values of FFR, CFR and iFR. We conclude that tachycardia may produce both overestimation or underestimation of coronary stenosis significance.
ARTICLE | doi:10.20944/preprints201812.0338.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: severe aortic stenosis; longitudinal axis strain; late gadolinium enhancement; cardiac magnetic resonance imaging
Online: 28 December 2018 (07:12:57 CET)
To analyze the predictive ability and incremental value of left ventricular longitudinal axis strain (LAS) and late gadolinium enhancement (LGE) using standard cardiovascular magnetic resonance (CMR) imaging for the diagnosis and prognosis of severe aortic stenosis (AS) in patients with an indication for aortic valve replacement. We conducted a prospective study on 128 patients with severe AS and 52 volunteers. The evaluation protocol included standard biochemistry tests, novel biomarkers of myocardial fibrosis, 12-lead electrocardiograms and 24-hour Holter, the 6-minute walk test and extensive echocardiographic and CMR imaging studies. Outcomes were defined as the composite of major cardiovascular events (MACEs). Among AS patients, most (n = 17, 77.2%) of those who exhibited LGE at CMR imaging had MACEs during follow-up. Kaplan-Meier curves for event-free survival showed a significantly higher rate of MACEs in patients with LGE (p < 0.01) and decreased LAS (p < 0.001). In Cox regression analysis, only reduced LAS [hazard ratio 1.33, 95%CI (1.01 to 1.74), p < 0.01] and the presence of LGE [hazard ratio 11.3, 95%CI (1.82 to 70.0), p < 0.01] were independent predictors for MACEs. The predictive value increased if both LGE and reduced LAS were added to LVEF. None of the biomarkers of increased collagen turnover exhibited any predictive value for MACEs. LAS by CMR is an independent predictor of outcomes in patients with AS and provides incremental value beyond the assessment of LVEF and the presence of LGE.
ARTICLE | doi:10.20944/preprints202304.0046.v2
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: Lumbar spinal stenosis; Spinal decompression; Minimally invasive surgery; Mini-open; Disc herniation; Post-decompression; Instability
Online: 19 June 2023 (15:17:06 CEST)
BackgroundIndex level disc herniation following lumbar spinal decompression is somewhat overlooked as postoperative complication, resulting in return of symptoms. It is proposed that the combination of local instability and degenerated disc is more likely to result in disc herniation. There is no literature comparing post-decompression disc herniation rates between different techniques. This study compares the postoperative disc herniation rates of the "mini-open" laminectomy versus the tubular system decompression.MethodsIn a retrospective comparative study, 563 patient files who underwent primary lumbar spinal decompression, were reviewed and divided into two groups, distinguished by surgical technique. Demographic, clinical, and postoperative data were collected and compared using independent two-tailed t-test and Fisher's exact test with significance set at p<0.05. Primary outcome: comparison of post-decompression surgery, index level, disc herniation occurrence between two surgical techniques.ResultsPostoperative index level disc herniation was significantly lower in the minimally invasive surgery group with 2 cases (0.8%) versus 19 cases (5.8%) in the "mini-open" group [p=0.002]. Disc herniation following single level and multi-level operations were also significantly lower in the minimally invasive group compared with the "mini-open" group (2 versus 11 and 0 versus 8 respectively; p<0.05).ConclusionPostoperative index level disc herniation following lumbar spinal decompression occurs in 3.7% of surgeries. Minimally invasive surgery is found to result in less herniations then "mini-open".
ARTICLE | doi:10.20944/preprints202206.0230.v1
Subject: Medicine And Pharmacology, Hematology Keywords: COVID-19; carotid stenosis; abdominal aortic aneurysm; chronic limb-threatening ischemia; amputation; deep venous thrombosis
Online: 16 June 2022 (04:40:54 CEST)
Background: To investigate the effects of the COVID-19 lockdowns on the vasculopathic population. Methods: The Divisions of Vascular Surgery of the southern Italian peninsula joined this multicenter retrospective study conducted through cross-sectional survey. Each received a 13-point questionnaire, investigating the hospitalization rate of vascular patients in the first 11 months of the COVID-19 pandemic and in the preceding 11 months. Results: 27 out of 29 Centers were enrolled. April-December 2020 (7092 patients) vs 2019 (9161 patients): post-EVAR surveillance, treatment for Rutherford category 3 peripheral arterial disease, and asymptomatic carotid stenosis revascularization significantly decreased [1484 (16.2%) vs 1014 (14.3%), p=0.0009; 1401 (15.29%) vs 959 (13.52%), p=0.0006; and 1558 (17.01%) vs 934 (13.17%), p<0.0001, respectively]; while revascularization or major amputations for chronic limb-threatening ischemia, and urgent revascularization for symptomatic carotid stenosis significantly increased [1204 (16.98%) vs 1245 (13.59%), p<0.0001; 355 (5.01%) vs 358 (3.91%), p=0.0007; and 153 (2.16%) vs 140 (1.53%), p=0.0009, respectively]. Conclusions: The suspension of elective activities during the COVID-19 pandemic caused a significant reduction in asymptomatic carotid stenosis revascularization, treatment for Rutherford 3 peripheral arterial disease, post-EVAR surveillance. Contestually, we observed a significant increase in urgent revascularization for symptomatic carotid stenosis, and revascularization or major amputations for chronic limb-threatening ischemia.
ARTICLE | doi:10.20944/preprints202004.0107.v1
Subject: Engineering, Control And Systems Engineering Keywords: Discrete Multiphysics Modelling; Smoothed Particle Hydrodynamics; Lattice Spring Model; Particle-base method; Aortic Valve; Calcification; Stenosis
Online: 7 April 2020 (13:33:02 CEST)
This study proposes a 3D particle-base (discrete) multiphysics approach for modelling calcification in the aortic valve. Different stages of calcification (from mild to severe) were simulated, and their effect on the cardiac output assessed. The cardiac flow rate decreases with the level of calcification. In particular, there is a critical level of calcification below which the flow rate decreases dramatically. Mechanical stress on the membrane is also calculated. The results show that, as calcification progresses, spots of high mechanical stress appear. Firstly, they concentrate in the regions connecting two leaflets; when severe calcification is reached, then they extend to the area at the basis of the valve.
REVIEW | doi:10.20944/preprints202306.0559.v1
Subject: Medicine And Pharmacology, Otolaryngology Keywords: Bone conduction; Cartilage conduction; Hearing device; Amplification; Aural atresia; Canal stenosis; Conductive hearing loss; Chronic otitis media
Online: 7 June 2023 (13:22:41 CEST)
A relatively loud sound is audible when a vibrator is attached to the aural cartilage. This form of conduction is referred to as cartilage conduction (CC). In Japan, a new type of hearing aid has been developed using CC and is available in clinical practice since 2017. A clinical study conducted prior to its launch demonstrated its benefits, particularly in patients with aural atresia who were unable to use air-conduction hearing aids. Several studies have been published on the benefits of CC hearing aids since their introduction in clinical practice. Most of the patients included in these studies had canal stenosis or aural atresia, and the purchase rates of CC hearing aids in these patients were relatively high. However, the number of patients with open ears was small, with overall poor results in the trials, with the exception in patients with continuous otorrhea. CC hearing aids are considered a good option for compensating hearing loss in ears with canal stenosis or atresia in both bilateral and unilateral cases. However, CC hearing aids are not currently considered the first choice for patients with an open ear,.
REVIEW | doi:10.20944/preprints202108.0439.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: extracellular matrix; glycosaminoglycans; inflammatory bowel disease; ulcerative colitis; Crohn´s disease; fibrosis; stenosis; magnetic resonance imaging; elastography; histopathology
Online: 23 August 2021 (13:20:23 CEST)
Work from the last years indicate that the extracellular matrix (ECM) plays a direct role in vari-ous cellular processes including proliferation, migration and differentiation. Besides homeostat-ic processes, its regulatory function in inflammation becomes more and more evident. In in-flammation like inflammatory bowel disease, the ECM composition is constantly remodeled which can result in a structuring of fistulizing disease course. Thus, tracking early ECM changes might bear the potential to predict the disease course. In this review, we will provide an over-view of relevant diagnostic methods focusing on ECM changes.
ARTICLE | doi:10.20944/preprints202307.0214.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: 3D printing; accuracy; calcification; cardiovascular disease; computed tomography; coronary artery disease; coronary stenosis; micro-computed tomography; plaque; synchrotron radiation
Online: 4 July 2023 (11:15:11 CEST)
Synchrotron radiation computed tomography (SRCT) allows more accurate calcified plaque and coronary stenosis assessment as a result of its superior spatial resolution, however, typical micro-computed tomography (micro-CT) systems have even higher resolution. The purpose of this study was to compare performance of high-resolution micro-CT with SRCT in the assessment of calcified plaques and a previously published dataset of coronary stenosis assessment. This experimental study involved micro-CT scanning of three-dimensional printed coronary artery models with calcification in situ used in our previously published SRCT study on coronary stenosis assessment. Measurements of coronary stenosis utilizing both modalities were compared using a paired sample t-test. The degrees of stenosis measured on all but one micro-CT dataset were statistically significantly lower than the corresponding SRCT measurements reported in our previous paper (p<0.0005-0.05). This indicates that the superior spatial resolution of micro-CT was able to further reduce over-estimation of stenosis caused by extensive calcification of coronary arteries and hence false positive results. This study shows that high-resolution micro-CT outperforms SRCT in both calcified plaque and coronary stenosis assessment. This finding will become clinically important for cardiovascular event prediction and enable reclassification of individuals with low and intermediate risk into appropriate risk categories when the technical challenges of micro-CT in clinical practice such as the small field of view and demanding on image processing power are addressed.