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Artigo em Inglês | MEDLINE | ID: mdl-30878425


OBJECTIVES: The aim of the present long-term study was to assess the incidence and mode of valve hemodynamic deterioration (VHD) of bioprosthetic aortic valves, as well as associated factors. BACKGROUND: Modern definitions of bioprosthetic valve deterioration recommend the use of echocardiography for the assessment of transprosthetic gradients and valvular regurgitation. METHODS: A total of 466 consecutive patients (mean age 73.5 ± 7.5 years, 56.0% women) underwent surgical bioprosthetic aortic valve replacement between 1994 and 2014. Clinical assessment, transthoracic echocardiography, and laboratory testing were performed at baseline and follow-up. VHD was defined as mean transprosthetic gradient ≥30 mm Hg and/or at least moderate valvular regurgitation on echocardiography. Patient-prosthesis mismatch was defined as an effective orifice area indexed to body surface area ≤0.8 cm2/m2. RESULTS: Patients were followed for a median of 112.3 months (interquartile range: 57.7 to 147.7 months). Among patients with complete follow-up (n = 383), 70 subjects (18.3%; 4.8% per valve-year) developed VHD after a median of 32.4 months (interquartile range: 12.9 to 87.2 months; stenosis, n = 45; regurgitation, n = 16; both, n = 9). Factors associated with VHD by multivariate regression analysis were serum creatinine >2.1 mg/dl (hazard ratio [HR]: 4.143; 95% confidence interval [CI]: 1.740 to 9.866; p = 0.001), porcine tissue valves (HR: 2.241; 95% CI: 1.356 to 3.706; p = 0.002), arterial hypertension (HR: 3.022; 95% CI: 1.424 to 6.410; p = 0.004), and patient-prosthesis mismatch (HR: 1.931; 95% CI: 1.102 to 3.384; p = 0.022). By Kaplan-Meier analysis, elderly subjects showed faster development of VHD (age <70 years, 133.5 months [95% CI: 116.2 to 150.8 months]; 70 to 80 years, 129.1 months [95% CI: 112.4 to 145.7 months]; >80 years, 100.3 months [95% CI: 63.6 to 136.9 months]; p = 0.023). By multivariate Cox regression, age, diabetes, concomitant coronary artery bypass grafting, creatinine, and VHD (p < 0.05) were significantly associated with mortality. CONCLUSIONS: On the basis of echocardiography, every fifth patient developed VHD after surgical bioprosthetic heart valve replacement. VHD was associated with renal impairment, the use of porcine tissue valves, arterial hypertension, and patient-prosthesis mismatch. Patients younger than 70 years were not affected by faster VHD.

JACC Cardiovasc Imaging ; 12(2): 225-232, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30553685


OBJECTIVES: Decision making in severe aortic stenosis (AS) requires a comprehensive pre-operative evaluation of the risk-to-benefit ratio. The aim of this study was to assess whether certain pre-operative symptoms are associated with outcome after surgical aortic valve replacement (SAVR). BACKGROUND: The cardinal symptoms of AS indicating a need for intervention are angina, symptoms of heart failure, and syncope. Nevertheless, it remains unknown whether the presence of these more advanced symptoms conveys an increased risk after SAVR and whether the detection of early symptoms in patients with asymptomatic AS should be emphasized more in routine clinical practice. METHODS: A total of 625 patients with isolated severe AS undergoing elective SAVR were prospectively enrolled in this long-term observational study. RESULTS: Patients experiencing syncope had significantly smaller left ventricular diameters (p = 0.02), left atrial diameters (p = 0.043), right ventricular diameters (p = 0.04), and right atrial diameters (p = 0.001), smaller aortic valve areas (p = 0.048), and lower indexed stroke volumes (p = 0.043) compared with patients without syncope. Syncope conveyed an increased risk for mortality after SAVR that persisted after multivariate adjustment for a bootstrap-selected confounder model, with an adjusted hazard ratio of 2.27 (95% confidence interval: 1.04 to 4.95; p = 0.04) for 1-year short-term mortality and an adjusted hazard ratio of 2.11 (95% confidence interval: 1.39 to 3.21; p < 0.001) for 10-year long-term mortality. In contrast, pre-operative dyspnea, angina, and reduced left ventricular function were not significantly associated with outcomes. CONCLUSIONS: This long-term observational study in a large contemporary cohort of patients with AS for the first time demonstrates that syncope represents an underestimated threat in aortic stenosis, associated with poor prognosis after SAVR. Importantly, other primary indications for SAVR (i.e., dyspnea, angina, and decreased left ventricular function) were associated with significantly better post-operative outcomes than syncope. Patients experiencing syncope displayed a specific pathophysiologic phenotype characterized by a smaller aortic valve area, smaller cardiac cavities, and lower stroke volumes.

J Environ Manage ; 151: 416-26, 2015 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-25602695


Lake eutrophication is a critical issue in the interplay of water supply, environmental management, and ecosystem conservation. Integrated sensing, monitoring, and modeling for a holistic lake water quality assessment with respect to multiple constituents is in acute need. The aim of this paper is to develop an integrated algorithm for data fusion and mining of satellite remote sensing images to generate daily estimates of some water quality parameters of interest, such as chlorophyll a concentrations and water transparency, to be applied for the assessment of the hypertrophic Albufera de Valencia. The Albufera de Valencia is the largest freshwater lake in Spain, which can often present values of chlorophyll a concentration over 200 mg m(-3) and values of transparency (Secchi Disk, SD) as low as 20 cm. Remote sensing data from Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat Thematic Mapper (TM) and Enhance Thematic Mapper (ETM+) images were fused to carry out an integrative near-real time water quality assessment on a daily basis. Landsat images are useful to study the spatial variability of the water quality parameters, due to its spatial resolution of 30 m, in comparison to the low spatial resolution (250/500 m) of MODIS. While Landsat offers a high spatial resolution, the low temporal resolution of 16 days is a significant drawback to achieve a near real-time monitoring system. This gap may be bridged by using MODIS images that have a high temporal resolution of 1 day, in spite of its low spatial resolution. Synthetic Landsat images were fused for dates with no Landsat overpass over the study area. Finally, with a suite of ground truth data, a few genetic programming (GP) models were derived to estimate the water quality using the fused surface reflectance data as inputs. The GP model for chlorophyll a estimation yielded a R(2) of 0.94, with a Root Mean Square Error (RMSE) = 8 mg m(-3), and the GP model for water transparency estimation using Secchi disk showed a R(2) of 0.89, with an RMSE = 4 cm. With this effort, the spatiotemporal variations of water transparency and chlorophyll a concentrations may be assessed simultaneously on a daily basis throughout the lake for environmental management.

Lagos/química , Qualidade da Água/normas , Abastecimento de Água/normas , Mineração de Dados , Ecossistema , Monitoramento Ambiental/métodos , Astronave , Espanha