Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Int Urol Nephrol ; 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358673

RESUMO

PURPOSE: To evaluate the role of urinary hyaluronic acid (HA) as a diagnostic marker in urothelial carcinoma (UCC), squamous cell carcinoma (SCC), and adenocarcinoma (ADC) of urinary bladder and compare it with urine cytology. METHODS: HA was estimated in 170 subjects divided into three groups. Group I: UCC 88 patients, 28 with SCC and 12 with ADC; group II: 34 patients with benign bladder tumors; and group III: 10 healthy bladders. HA was estimated in urine and then readjusted to creatinine (HA/Cr) and protein (HA/Pr) in urine. Urine cytology was evaluated. RESULTS: The mean ± SD level HA was higher in UCC (589 ± 72), SCC (637 ± 45), and ADC (526 ± 30) as compared with benign (476 ± 92) and normal (277 ± 44) groups regardless the grade of tumor (p < 0.0001). A cutoff value of 490 ng/ml was calculated to detect malignancy with sensitivity of 98% and specificity of 66%. PPV, NPV, and ACC were 88.6%, 94.1%, and 90%, respectively. Urine cytology showed sensitivity of, specificity, PPV, NPV, and ACC of 52.6%, 90%, 90.45, 50%, and 65.5%, respectively. HA/Pr and HA/Cr, cutoff values for detection of malignancy were 84.9 and 9.6 but with less predictive values. Histopathological type was the only independent factor affecting level of HA on multivariate analysis, (p = 0.012, Exp (B) 14.98, 95% CI 1.8-121). CONCLUSION: Combination of urinary HA and urine cytology provides reliable marker of bladder cancer.

2.
Interact Cardiovasc Thorac Surg ; 30(1): 39-46, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31873743

RESUMO

OBJECTIVES: Clinical and subclinical leaflet thromboses are increasingly recognized complications following transcatheter aortic valve replacement. Identification of the risk factors is important to mitigate the occurrence of leaflet thrombosis in transcatheter aortic valves (TAVs) and ensure their long-term function. The goal of this study was to determine the effect of incomplete expansion of TAVs on the likelihood of leaflet thrombosis following transcatheter aortic valve replacement. METHODS: Using experimental and computational methods, 3-dimensional unsteady flow fields of 26-mm SAPIEN 3 valves expanded to 3 different diameters (i.e. 26.0 mm, 23.4 mm and 20.8 mm) were determined in patient-specific geometries. The diameters corresponded to 100%, 90% and 80% stent expansion, respectively. To address the potential difference in the likelihood of leaflet thrombosis, blood residence time (i.e. stasis) and viscous shear stress on the surface of TAV leaflets were quantified and compared. RESULTS: The results indicated that TAV underexpansion increased blood stasis on the TAV leaflets. Blood residence time on the surface of the leaflets after 80% and 90% TAV expansion on average was 9.4% and 4.1% more than that of the fully expanded TAV, respectively. In addition, areas of blood stasis time of more than 0.5 s, which are highly prone to platelet activation, increased linearly as the degree of TAV underexpansion increased. CONCLUSIONS: Incomplete expansion of TAVs increases blood stasis on the surface of TAV leaflets. Regions of blood stasis promote platelet activation and thrombotic events. TAV underexpansion can therefore increase the risk of leaflet thrombosis in patients with transcatheter aortic valve replacement.

3.
Minerva Gastroenterol Dietol ; 65(1): 70-76, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30417630

RESUMO

INTRODUCTION: Endoscopic hemostasis in patients with non-variceal bleeding (NVGIB) with standard therapy has improved outcomes. However, persistent bleeding and re-bleeding continues to drive morbidity and mortality. Use of over-the-scope clips (OTSC) is an emerging treatment modality for managing gastrointestinal (GI) bleeding. We performed a systematic review and meta-analysis to evaluate the ability of OTSC to achieve primary hemostasis and re-bleeding rates as primary therapy and rescue endoscopic interventions in patients with NVGIB. EVIDENCE ACQUISITION: We searched articles in PubMed, Ovid Medline In- Process & Other Non-Indexed Citations, Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus from inception to July 2017 using keywords such as "OTSC" and "NVGIB." EVIDENCE SYNTHESIS: A total of 16 studies which involved 475 patients met the inclusion criteria. 288 patients were treated with OTSC as primary therapy while 187 patients were treated with OTSC as rescue therapy. Primary hemostasis rate achieved with primary endoscopic therapy with OTSC was 0.93 (95% CI: 0.89-0.96). Similarly, primary hemostasis rate achieved with rescue endoscopic therapy with OTSC was 0.91 (95% CI: 0.84-0.95). Re-bleeding rates after primary endoscopic therapy with OTSC was 0.21 (95% CI:0.08-0.43) and 0.25 (95% CI:0.17-0.34) with rescue therapy. There was a decreased risk of re-bleeding in patients treated with OTSC as primary therapy versus rescue therapy. RR=0.52 (95% CI: 0.31-0.89). CONCLUSIONS: This meta-analysis demonstrates success on the use of OTSC as primary and rescue therapy in the management of NVGIB. Further trials should clarify the ideal setting for the use of OTSC and assess the cost of these devices as compared to standard therapy.


Assuntos
Endoscopia Gastrointestinal , Hemorragia Gastrointestinal/terapia , Hemostase Endoscópica/instrumentação , Humanos
4.
Ann Biomed Eng ; 47(1): 97-112, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30229500

RESUMO

Computational modeling and simulation has become more common in design and development of bioprosthetic heart valves. To have a reliable computational model, considering accurate mechanical properties of biological soft tissue is one of the most important steps. The goal of this study was to present a non-invasive material characterization framework to determine mechanical propertied of soft tissue employed in bioprosthetic heart valves. Using integrated experimental methods (i.e., digital image correlation measurements and hemodynamic testing in a pulse duplicator system) and numerical methods (i.e., finite element modeling and optimization), three-dimensional anisotropic mechanical properties of leaflets used in two commercially available transcatheter aortic valves (i.e., Edwards SAPIEN 3 and Medtronic CoreValve) were characterized and compared to that of a commonly used and well-examined surgical bioprosthesis (i.e., Carpentier-Edwards PERIMOUNT Magna aortic heart valve). The results of the simulations showed that the highest stress value during one cardiac cycle was at the peak of systole in the three bioprostheses. In addition, in the diastole, the peak of maximum in-plane principal stress was 0.98, 0.96, and 2.95 MPa for the PERIMOUNT Magna, CoreValve, and SAPIEN 3, respectively. Considering leaflet stress distributions, there might be a difference in the long-term durability of different TAV models.


Assuntos
Bioprótese , Próteses Valvulares Cardíacas , Modelos Cardiovasculares , Desenho de Prótese , Humanos
5.
Artif Organs ; 42(11): E357-E368, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30198167

RESUMO

Transcatheter aortic valves provide superior systolic hemodynamic performance in terms of valvular pressure gradient and effective orifice area compared with equivalent size surgical bioprostheses. However, in depth investigation of the flow field structures is of interest to examine the flow field characteristics and provide experimental evidence necessary for validation of computational models. The goal of this study was to compare flow field characteristics of the three most commonly used transcatheter and surgical valves using phase-locked particle image velocimetry (PIV). 26-mm Edwards SAPIEN 3, 26-mm Medtronic CoreValve, and 25-mm Carpentier-Edwards PERIMOUNT Magna were examined in a pulse duplicator with input parameters matching ISO-5840, that is, heart rate of 70 beats/min, cardiac output of 5 L/min, and mean aortic pressure of 100 mm Hg. A 2D PIV system was used to obtain flow velocity and viscous shear stress fields during the entire cardiac cycle. In vitro testing showed that the mean transvalvular pressure gradient was lowest for SAPIEN 3, followed by CoreValve, and PERIMOUNT Magna surgical bioprosthesis. In addition, the viscous shear stress magnitude within the jet boundary layer was higher in PERIMOUNT Magna than CoreValve and SAPIEN 3 at the peak of the flow. However, the measured shear stress values were below the known threshold for platelet activation and red blood damage. Therefore, shear-induced platelet activation is unlikely to take place during systole in the three bioprosthetic heart valves. The PIV measurements can be used for verification and validation of computational simulations.


Assuntos
Próteses Valvulares Cardíacas , Hemodinâmica , Hidrodinâmica , Valva Aórtica/cirurgia , Bioprótese , Simulação por Computador , Humanos , Teste de Materiais , Modelos Cardiovasculares , Desenho de Prótese , Reologia , Estresse Mecânico , Substituição da Valva Aórtica Transcateter
6.
EuroIntervention ; 13(7): 811-819, 2017 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-28485280

RESUMO

AIMS: There is an increasing awareness of leaflet thrombosis following transcatheter aortic valve implantation (TAVI) and valve-in-valve (ViV) procedures. Nevertheless, the predisposing factors affecting transcatheter aortic valve (TAV) thrombosis have remained unclear. This study aimed to quantify the effects of reduced cardiac output (CO) on blood stasis on the TAV leaflets as a permissive factor for valve thrombosis. METHODS AND RESULTS: An idealised computational model representing a TAV was developed in a patient-specific geometry. Three-dimensional flow fields were obtained via a fluid-solid interaction modelling approach at different COs: 5.0, 3.5, 2.0 L/min. Blood residence time (BRT) was subsequently calculated on the leaflets. An association between reduced CO and increased blood stasis on the TAV leaflets was observed. At the end of diastole, larger areas of high BRT (>1.2 s) were observed at the leaflet's fixed edge at low COs. Such areas were calculated to be 2, 8, and 11% of the total surface area of leaflets at CO=5.0, 3.5, and 2.0 L/min, respectively, indicating a ~sixfold increase of BRT on the leaflets from the highest to the lowest CO. CONCLUSIONS: This study indicates an association between reduced CO and increased blood stasis on the TAV leaflets which can be regarded as a precursor of valve thrombosis.


Assuntos
Estenose da Valva Aórtica/cirurgia , Valva Aórtica/cirurgia , Trombose/patologia , Substituição da Valva Aórtica Transcateter , Idoso , Estenose da Valva Aórtica/diagnóstico , Simulação por Computador , Feminino , Próteses Valvulares Cardíacas/efeitos adversos , Humanos , Estresse Mecânico , Trombose/diagnóstico , Trombose/terapia , Substituição da Valva Aórtica Transcateter/métodos
7.
Eur J Cardiothorac Surg ; 51(5): 927-935, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28100471

RESUMO

OBJECTIVES: Leaflet thrombosis following transcatheter aortic valve replacement (TAVR) and valve-in-valve (ViV) procedures has been increasingly recognized. However, the factors affecting the post-TAVR/ViV thrombosis are not fully understood. This study aimed to investigate the effect of the geometric confinement of transcatheter aortic valve (TAV) on blood residence time (BRT) on the TAV leaflets and in turn on the post-TAVR valve thrombosis. METHODS: Two computational models, representing a surgical bioprosthesis and a TAV, were developed to study the effect of the geometric confinement on BRT on the leaflets in ViV setting/TAVR Intra-annular positioning. 3D flow fields were obtained via a one-way fluid-solid interaction modelling approach validated by experimental testing. BRT was compared between the two models by quantification and statistical analysis of the residence time of randomly distributed particles in close proximity of the leaflets. RESULTS: Significantly longer BRT on the leaflets was observed in the TAV compared to the surgical valve during different stages of the cardiac cycle. During forward flow, the mean value of BRT was found to be 39% higher in the TAV compared to the surgical bioprosthesis ( P < 0.0001). During diastole, specifically from end-systole to mid-diastole and from mid-diastole to the beginning of systole, the amount by which the mean BRT was higher for TAV compared to the surgical valve was 150% and 40%, respectively ( P < 0.0005). CONCLUSIONS: The geometric confinement of TAV by the failed bioprosthesis or the calcified native valve increases the BRT on the TAV leaflets. This may act as a permissive factor in valve thrombosis.


Assuntos
Estenose da Valva Aórtica/fisiopatologia , Hemodinâmica/fisiologia , Modelos Cardiovasculares , Trombose/fisiopatologia , Substituição da Valva Aórtica Transcateter/efeitos adversos , Valva Aórtica/fisiopatologia , Valva Aórtica/cirurgia , Próteses Valvulares Cardíacas/efeitos adversos , Humanos
8.
J Mech Behav Biomed Mater ; 62: 33-44, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27173827

RESUMO

Computational modeling has an important role in design and assessment of medical devices. In computational simulations, considering accurate constitutive models is of the utmost importance to capture mechanical response of soft tissue and biomedical materials under physiological loading conditions. Lack of comprehensive three-dimensional constitutive models for soft tissue limits the effectiveness of computational modeling in research and development of medical devices. The aim of this study was to use inverse finite element (FE) analysis to determine three-dimensional mechanical properties of bovine pericardial leaflets of a surgical bioprosthesis under dynamic loading condition. Using inverse parameter estimation, 3D anisotropic Fung model parameters were estimated for the leaflets. The FE simulations were validated using experimental in-vitro measurements, and the impact of different constitutive material models was investigated on leaflet stress distribution. The results of this study showed that the anisotropic Fung model accurately simulated the leaflet deformation and coaptation during valve opening and closing. During systole, the peak stress reached to 3.17MPa at the leaflet boundary while during diastole high stress regions were primarily observed in the commissures with the peak stress of 1.17MPa. In addition, the Rayleigh damping coefficient that was introduced to FE simulations to simulate viscous damping effects of surrounding fluid was determined.


Assuntos
Bioprótese , Próteses Valvulares Cardíacas , Valvas Cardíacas/fisiologia , Animais , Bovinos , Simulação por Computador , Análise de Elementos Finitos , Humanos , Teste de Materiais , Modelos Cardiovasculares , Estresse Mecânico
9.
Angiology ; 64(5): 336-42, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22942129

RESUMO

We estimated the prevalence of cardiovascular disease (CVD) risk and its clinical implications among 1 110 Omani patients with type 2 diabetes mellitus (DM) using 2 different CVD risk tools: the general Framingham risk profile (GFRP) and the joint World Health Organization/International Society of Hypertension (WHO/ISH) risk prediction charts. The GFRP tool identified higher proportion of patients compared with joint WHO/ISH tool at 10-year CVD risk 10% to <20% and at 20% to <30%. At CVD risk ≥30%, both assessment tools identified similar proportions of patients (22% vs 24%; P=.120). Compared with WHO/ISH charts, the GFRP identified almost double the number of men eligible for aspirin treatment at CVD risk thresholds of ≥10% (86% vs 43%). In women, the proportions were, 66% and 45%, respectively. For statins, the figures were, 60% and 37%, for men and 28% and 36%, for women. In conclusion, the GFRP overestimates the number of patients eligible for primary prevention of CVD compared with the joint WHO/ISH method.


Assuntos
Árabes/estatística & dados numéricos , Doenças Cardiovasculares/epidemiologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/etnologia , Indicadores Básicos de Saúde , Adulto , Idoso , Fármacos Cardiovasculares/economia , Fármacos Cardiovasculares/uso terapêutico , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/terapia , Estudos de Coortes , Custos de Medicamentos , Feminino , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/economia , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Masculino , Pessoa de Meia-Idade , Omã/epidemiologia , Padrões de Prática Médica , Prevalência , Fatores de Risco
10.
Oman Med J ; 27(6): 465-70, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23226816

RESUMO

OBJECTIVES: To investigate whether younger patients with type 2 diabetes mellitus have higher glycated hemoglobin A1c (HbA1c) levels compared to older patients, and to determine the factors associated with higher HbA1c levels. METHODS: Data from 1,266 patients from all over Oman were used to obtain the mean HbA1c level, odds ratios (OR), and 95% confidence intervals (CI) from multiple logistic regression models with age groups, sex, duration of diabetes, diabetes treatment, body mass index, estimated glomerular filtration rate (eGFR), tobacco use, and healthcare index as predictors of good (HbA1c <7%) vs. poor (≥7%) glycemic control. RESULTS: Mean HbA1c levels were 8.9, 8.3, and 7.8 in the age groups 20-39, 40-59 and 60+ years, respectively. After controlling for all other covariates, the OR of good glycemic control increased with age, 40-59 years old (OR=1.7; 95% CI 1.1 to 2.6) and 60+ year (OR=2.5; 95% CI 1.6 to 4.0), female gender (OR=1.5; 95% CI 1.2 to 2.0) and in patients with eGFR ≥60 mL/min/1.73 m(2) (OR=1.9; 95% CI 1.1 to 3.3). Longer duration of diabetes (≥5 years) and treatment with oral agents or insulin were inversely related to good glycemic control. CONCLUSION: Younger Omani adults exhibit worse glycemic levels compared to older adults posing a formidable challenge to diabetes care teams.

11.
Open Cardiovasc Med J ; 6: 133-40, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23166566

RESUMO

BACKGROUND: Despite the high burden of type 2 diabetes mellitus (T2DM) in Oman, there are scarce data from a nationally representative sample on the level of glycaemia and other cardiovascular (CVD) risk factor control. OBJECTIVE: To estimate the proportion of patients with T2DM at goal for glycaemia and CVD risk factors using the National Diabetes Guidelines (NDG) and the American Diabetes Association (ADA) clinical care guidelines; and to assess the quality of selected services provided to patients with T2DM. METHODS: A sample of 2,551 patients (47% men) aged ≥20 years with T2DM treated at primary health care centers was selected. Patient characteristics, medical history and treatment were collected from case notes, Diabetes Registers and computer frameworks including the use of the last 3 laboratory investigations results and blood pressure (BP) readings recorded in 2007. RESULTS: The overall mean age of the cohort was 54±13 years with an average median duration of diabetes of 4 (range 2 to 6) years. Over 80% of patients were overweight or obese (body mass index (BMI) of ≥25 Kg/m(2)). Sixty-nine percent were on oral anti-diabetic medication, 52% on anti-hypertensives and 40% on lipid lowering drugs. Thirty percent of patients were at goal for glycosylated haemoglobin level (<7%), 26% for BP (systolic/diastolic <130/80 mmHg), 55% for total cholesterol (<5.2 mmol/l), 4.5% for low-density lipoprotein cholesterol (<1.8 mmol/l), 52% for high-density lipoprotein cholesterol (>1 mmol/l for men, >1.3 mmol/l for women), and 61% for triglycerides (<1.7 mmol/l). Over 37% had micro-albuminuria and 5% had diabetic nephropathy. CONCLUSION: Control of hyperglycaemia and other CVD risk factor appears to be suboptimal in Omani patients with T2DM and need to be addressed in the triad of patient, physician and health system.

12.
Ann Saudi Med ; 30(4): 265-70, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20622342

RESUMO

BACKGROUND AND OBJECTIVES: Oman provides comprehensive care for the detection and management of diabetes during pregnancy with the goal of reducing or eliminating adverse outcomes for mothers and newborns. We assessed the outcome of pregnancies complicated with diabetes as compared to healthy controls. SUBJECTS AND METHODS: A 1-year retrospective review of registry records was conducted on pregnant women with gestational diabetes mellitus (GDM) and pre-gestational diabetes mellitus (PGDM). Of the 5394 women registered, 225 had GDM and 56 had PGDM. Fourteen cases of GDM and 2 cases of PGDM were excluded. For each patient recruited, the next healthy control of the same age and parity was selected. RESULTS: Nearly 80% of diabetic women achieved good glycemic control (hemoglobin A1c <7%). Adjusted for hypertension and body mass index, the risk of macrosomia was three times higher among women with GDM (OR=3.03, 95% CI=1.36-6.75) and up to seven times higher among those with PGDM (OR=7.20, 95% CI=2.30-22.61). A significantly higher risk of cesarean delivery was observed among women with GDM (OR=2.70, 95% CI=1.17-4.03) and PGDM (OR=4.39, 95% CI=1.68-11.49). Admission to the special care baby unit was higher among infants born to mothers with PGDM (OR=5.70, 95% CI=2.40-13.51) and GDM (OR=2.85, 95% CI=1.68-4.83). CONCLUSION: The findings indicate that many of the unfavorable pregnancy outcomes of diabetes for women and infants have not been brought under control despite the comprehensive care provided. Further studies are recommended to evaluate the system of care provided to pregnant women and to identify gaps in achieving the goals of the St. Vincent Declaration.


Assuntos
Cesárea/estatística & dados numéricos , Diabetes Gestacional/fisiopatologia , Macrossomia Fetal/epidemiologia , Resultado da Gravidez , Adulto , Estudos de Casos e Controles , Diabetes Gestacional/terapia , Feminino , Hemoglobina A Glicada/metabolismo , Humanos , Pessoa de Meia-Idade , Omã/epidemiologia , Gravidez , Sistema de Registros , Estudos Retrospectivos , Adulto Jovem
14.
Diabetes Res Clin Pract ; 75(2): 241-5, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16875755

RESUMO

We used two cross-sectional surveys involving 6356 Omanis aged >or= 20 years to estimate the effect of the 1997 American Diabetes Association (ADA) criteria on the prevalence of diabetes mellitus in Oman and develop a validated optimal fasting plasma glucose (FPG) cut-point which best predicts diabetes diagnosed 2-h post oral glucose tolerance test. Applying the 1997 ADA criteria to Oman would underestimate diabetes by 18%. The sensitivity of the ADA criteria was 68.3% (95% CI 64.0-72.4%) and specificity was 98.6% (95% CI 98.2-98.9%). Receiver-operating characteristic (ROC) curve depicted FPG>5.9 mmol/l to best predict 2-h post-load glucose >or=11.1 mmol/l. The area under the ROC curve was 0.95 (95% CI 0.94-0.95%) with no significant difference between obese and non-obese individuals. This cut-point had a sensitivity of 87.5% (95% CI 84.3-90.3%), specificity of 90.8% (95% CI 89.9-91.7%) and likelihood ratio of 9.5. On validation in an independent population, the sensitivity and specificity of the depicted cut-point remained high 84.2% (95% CI 77.0-89.8%) and 80.2% (95% CI 78.0-82.4%) compared to the ADA values 60.4% and 96.6%, respectively. Our study identified a lower cut-point to diagnose diabetes than that suggested by the 1997 ADA criteria.


Assuntos
Diabetes Mellitus/epidemiologia , Jejum , Intolerância à Glucose/epidemiologia , Islamismo , Adulto , Estudos Transversais , Feminino , Inquéritos Epidemiológicos , Humanos , Hiperglicemia/epidemiologia , Masculino , Oriente Médio/epidemiologia , Omã/epidemiologia , Prevalência , Sensibilidade e Especificidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA