A parallel fully-coupled fluid-structure interaction simulation of a cerebral aneurysm

A parallel fully-coupled approach has been developed for the fluid-structure interaction problem in a cerebral artery with aneurysm. An Arbitrary Lagrangian-Eulerian formulation based on the side-centered unstructured finite volume method [2] is employed for the governing incompressible Navier-Stokes equations and the classical Galerkin finite element formulation is used to discretize the constitutive law for the Saint VenantKirchhoff material in a Lagrangian frame for the solid domain. A special attention is given to construct an algorithm with exact fluid mass/volume conservation while obeying the global discrete geometric conservation law (DGCL). The resulting large-scale algebraic linear equations are solved using a one-level restricted additive Schwarz preconditioner with a block-incomplete factorization within each partitioned sub-domains. The parallel implementation of the present fully coupled unstructured fluid-structure solver is based on the PETSc library for improving the efficiency of the parallel algorithm. The proposed numerical algorithm is applied to a complicated problem involving unsteady pulsatile blood flow in a cerebral artery with aneurysm as a realistic fluid-structure interaction problem encountered in biomechanics

Serum levels of TNF-α and osteoprotegerin and bone mineral density in patients with Behçet’s Disease

Objectives: Osteoporosis is commonly developed due tonatural course of Behçet’s disease (BD) and therapeuticagents. It was aimed to investigate levels of osteoprotegerinand TNF-α (tumor necrosis factor), and bone mineral density(BMD) and correlation between them in BD.Materials and methods: The study included two groupsas the study and the control group. Serum levels of TNF-α,osteoprotegerin, osteocalcine, erythrocyte sedimentation rate(ESR), C-reactive protein (CRP), and urinary creatinine anddeoxypyridinoline along with BMD level were evaluated andcompared. Correlation between TNF-α and osteoprotegerinlevel was investigated.Results: The study enrolled 41 BD patients and 36 agedmatchedcontrol subjects. Mean age was 42.26±11.64 and41.66±70.99, in the study and control groups, respectively.There was no significant difference in body mass index(BMI) of subjects between groups (p>0.05). Level of TNF-α(p<0.001), deoxypyridinoline (p<0.001) and osteocalcine(p=0.041) was significantly higher in the study group comparedto the control group. Osteoprotegerin was lower inBD patients, but the difference was not significant (p>0.05).Urinary deoxypyridinoline/ urinary creatinine ratio in patientswith BD was significantly higher than those in control group(p=0.030). Patients had significantly lower BMD comparfedto the control group, except L2-L4 vertebral area (p<0.001,p<0.001, p=0.035, p<0.001, p=0.012, p<0.001, p<0.001 andp=0.111, respectively). No correlation was found betweenTNF-α and osteoprotegerin.Conclusions: The present study indicated that TNF-α andBMD was negatively correlated with each other and TNF-αhad an effect on osteoporotic process in patients with BD.Osteoprotegerin level was not decreased, and not correlatedwith TNF-α.Key words: Behçet’s disease, osteoprotegerin, TNF-α, osteocalcin

Acute effects of cardiac resynchronization therapy on arterial distensibility and serum norepinephrine levels in advanced heart failure

Background: Cardiac resynchronization therapy (CRT) has become an accepted method fortreating refractory heart failure (HF). Arterial distensibility is an index of arterial stiffnessand a surrogate marker for atherosclerosis. The present study aims to assess the acute effects of ventricular resynchronization therapy with biventricular stimulation on arterial distensibility, echocardiographic parameters and serum norepinephrine levels in patients with drugrefractory HF.Methods: Fourteen cardiac HF patients (53.6 ± 9.1; 39–67 years, 7 woman) were enrolled for CRT. Patients had an advanced cardiac HF (NYHA III–IV functional class) due to non-ischemic dilated cardiomyopathy, with a left ventricular ejection fraction (LVEF) &lt; 35% and QRS duration ≥ 120 ms. Blood samples for norepinephrine and B-type natriuretic peptidewere collected before 24 h biventricular implantation and after 48 h of CRT. Transthoracic echocardiography was used to evaluate arterial distensibility and cardiovascular condition.Results: Although systolic blood pressure, diastolic blood pressure, LV end-diastolic diameter, LV end-systolic diameter, serum B-type natriuretic peptide, and serum norepinephrine levels significantly decreased after CRT implantation; EF and aortic distensibility significantly increased (p &lt; 0.05). There was no significance in the hemodynamic and echocardiographic values, norepinephrine and B-type natriuretic peptide levels in pre- and post-CRT between man and woman.Conclusions: The major findings of this study are that in patients with cardiac HF in acute period, after implantation of CRT serum norepinephrine levels decrease and the arterial distensibility improves

Increased P-wave dispersion in patients with newly diagnosed lichen planus

OBJECTIVE: Lichen planus is a chronic inflammatory autoimmune mucocutaneous disease. Recent research has emphasized the strong association between inflammation and both P-wave dispersion and dyslipidemia. The difference between the maximum and minimum P-wave durations on an electrocardiogram is defined as P-wave dispersion. The prolongation of P-wave dispersion has been demonstrated to be an independent risk factor for developing atrial fibrillation. The aim of this study was to investigate P-wave dispersion in patients with lichen planus. METHODS: Fifty-eight patients with lichen planus and 37 age- and gender-matched healthy controls were included in this study. We obtained electrocardiographic recordings from all participants and used them to calculate the P-wave variables. We also assessed the levels of highly sensitive C-reactive protein, which is an inflammatory marker, and the lipid levels for each group. The results were reported as the means ± standard deviations and percentages. RESULTS: The P-wave dispersion was significantly higher in lichen planus patients than in the control group. Additionally, highly sensitive C-reactive protein, LDL cholesterol, and triglyceride levels were significantly higher in lichen planus patients compared to the controls. There was a significant positive correlation between highly sensitive C-reactive protein and P-wave dispersion (r = 0.549,

Determinants of high sensitivity troponin T concentration in chronic stable patients with heart failure: Ischemic heart failure versus non-ischemic dilated cardiomyopathy

Background: Cardiac troponin T is a marker of myocardial injury, especially when measured by means of the high-sensitivity assay (hs-cTnT). The echocardiographic and clinical predictors of hs-cTnT may be different in ischemic heart failure (IHF) and non-ischemic dilated cardiomyopathy (DCM).Methods: Sixty consecutive patients (19 female, 41 male; mean age 56.3 ± 13.9 years) with stable congestive heart failure (33 patient with IHF and 27 patients with DCM), with New York Heart Association functional class I–II symptoms, and left ventricular ejection fraction &lt; 40% were included.Results: In patients with IHF peak early mitral inflow velocity (E), E/peak early diastolic mitral annular tissue Doppler velocity (Em) lateral, peak systolic mitral annular tissue Doppler velocity (Sm) lateral and logBNP were univariate predictors of hs-cTnT above median. But only E/Em lateral was an independent predictor of hs-cTnT above median (p = 0.04, HR: 1.2,CI: 1–1.4). In patients with DCM; left atrial volume index, male sex, Sm lateral and global longitudinal strain (LV-GLS) were included in multivariate model and LV-GLS was detected to be an independent predictor for hs-cTnT above median (p &lt; 0.05, HR: 0.7, CI: 0.4–1.0).Conclusions: While LV-GLS is an independent predictor of hs-cTnT concentrations in patients with DCM, E/Em lateral predicted hs-TnT concentrations in patients with IHF

A simplified acute kidney injury predictor following transcatheter aortic valve implantation: ACEF score

Background: Transcatheter aortic valve implantation (TAVI) is an effective, less invasive treatment alternative for symptomatic severe aortic stenosis (AS). Acute kidney injury (AKI) following TAVI is a common complication and is associated with worse outcomes. The age, creatinine, ejection fraction (ACEF) score is a simple scoring method, including only three parameters: age, creatinine, and ejection fraction (EF). The score was well established in predicting AKI after coronary interventions.Aims: We aimed to evaluate whether this simple scoring method, ACEF, may predict a development of AKI in patients who underwent TAVI.Methods: A total of 173 consecutive patients with symptomatic severe AS who underwent TAVI were included retrospectively. The primary endpoint of the study was the development of AKI. Study population was divided into two groups according to the presence of AKI. The ACEF score was calculated with the formula: age/EF + 1 (if baseline creatinine &gt;2 mg/dl).Results: Twenty-nine patients developed AKI. The median (interquartile range) ACEF score was 1.36 (1.20–1.58). The ACEF score was found to be an independent predictor of AKI (P &lt;0.001). The ACEF score ≥1.36 predicted AKI development with a sensitivity of 96.6% and specificity of 58.8%. Moreover, hypertension, hemoglobin levels, contrast volume, and aortic valve area (AVA) were found to be independent predictors of AKI.Conclusions: Our study revealed that the ACEF score was an independent predictor of AKI. A simple and objective score might be very useful in predicting AKI development in patients undergoing TAVI