5,502 research outputs found
Elective repair of abdominal aortic aneurysm: the evidence is in but the jury may still be out
info:eu-repo/semantics/publishedVersio
A multicriteria evaluation system for large real estate investments
As an economic engine of contemporary societies, the real estate market needs to be carefully analyzed in terms of both urban management and private or public investment. Information on this market’s behavior can facilitate the identification of turning points in societies’ economic history. Analysts should focus not only on conditioning variables and other important determinants of relevance to investment evaluations but also on the impacts of each variable or factor. Measuring these effects is a key activity in decision-making processes. Given real estate’s growing importance to sustainable economic growth, this study concentrates on creating a multicriteria model for evaluating large real estate investments. A constructivist, process-oriented approach was applied in group work sessions held with a panel of experts with experience in dealing with this issue. These specialists structured the problem of evaluating large real estate investments using value-focused thinking (VFT) and cognitive mapping. The best-worst method (BWM) was then applied to calculate trade-offs among decision criteria and calibrate the evaluation system. The results were presented to and validated by a representative of Instituto da Habitação e da Reabilitação Urbana (Institute for Housing and Urban Rehabilitation), who identified the advantages and limitations of the proposed model, and suggested possible improvements.info:eu-repo/semantics/publishedVersio
Tax Reforms and Network Effects
This paper investigates the effects of a tax reform that eliminates tax rate heterogeneity and cumulative taxation using a general equilibrium model with multiple sectors with market power. Industries are connected through input-output linkages, and changes in taxation are not confined within industries. We calibrate the model to Brazil, a country with a highly distorted tax system. The revenue-neutral tax reform generates gains of 7.8% of GDP and 1.9% of welfare. Just eliminating VAT rate dispersion leads to a 5.9% increase in GDP. Due to propagation effects, in 10 sectors direct taxes increased but output and profits did not fall
Has Carotid Intima-Media Thickness Prognostic Impact in Patients with High Cardiovascular Risk? A Long-Term Cohort Study
BACKGROUND:
Carotid intima-media thickness (CIMT) is an established surrogate marker for cardiovascular events in patients with intermediate risk. In patients with high cardiovascular risk or established cardiovascular disease, the impact of CMIT measurement on risk stratification for future events is less clear. Our objective was to evaluate the impact of CIMT on the occurrence of cardiovascular events in a cohort of individuals with high cardiovascular risk, in long-term follow-up.
METHODS:
We analyzed 296 individuals, mean follow-up of 6.9 ± 2.2 years. Individuals were divided into tertiles according to CIMT. Tertiles were compared in terms of baseline characteristics and outcomes during follow-up-all-cause mortality and composite outcome (mortality, acute coronary syndromes, coronary revascularization, stroke/transient ischemic attack, heart failure, or cardiovascular admission).
RESULTS:
Our population had a mean age of 65 ± 9 years at the beginning of the study, 55% males. Patients with higher CIMT showed a trend for higher cardiovascular mortality (P = 0.084) and for the composite outcome (P = 0.049). A CIMT ≥ 0.85 mm was also associated with higher rate of events; however, CIMT was not an independent predictor of outcome after adjustment for age and gender. CIMT assessment was useful in patients with hypertension, hyperlipidemia, and metabolic syndrome and in nondiabetic patients. For the composite outcome, it was also useful in females, smokers, and in patients without coronary artery disease.
CONCLUSIONS:
Patients with higher CIMT have worst outcome, but this was mainly driven by age and gender. CIMT is useful as a prognostic marker in specific subsets of patients.info:eu-repo/semantics/publishedVersio
Prognostic Value of a New Cardiopulmonary Exercise Testing Parameter in Chronic Heart Failure: Oxygen Uptake Efficiency at Peak Exercise - Comparison with Oxygen Uptake Efficiency Slope
INTRODUCTION: A growing body of evidence shows the prognostic value of oxygen uptake efficiency slope (OUES), a cardiopulmonary exercise test (CPET) parameter derived from the logarithmic relationship between O(2) consumption (VO(2)) and minute ventilation (VE) in patients with chronic heart failure (CHF).
OBJECTIVE: To evaluate the prognostic value of a new CPET parameter - peak oxygen uptake efficiency (POUE) - and to compare it with OUES in patients with CHF.
METHODS: We prospectively studied 206 consecutive patients with stable CHF due to dilated cardiomyopathy - 153 male, aged 53.3±13.0 years, 35.4% of ischemic etiology, left ventricular ejection fraction 27.7±8.0%, 81.1% in sinus rhythm, 97.1% receiving ACE-Is or ARBs, 78.2% beta-blockers and 60.2% spironolactone - who performed a first maximal symptom-limited treadmill CPET, using the modified Bruce protocol. In 33% of patients an cardioverter-defibrillator (ICD) or cardiac resynchronization therapy device (CRT-D) was implanted during follow-up. Peak VO(2), percentage of predicted peak VO(2), VE/VCO(2) slope, OUES and POUE were analyzed. OUES was calculated using the formula VO(2) (l/min) = OUES (log(10)VE) + b. POUE was calculated as pVO(2) (l/min) / log(10)peakVE (l/min). Correlation coefficients between the studied parameters were obtained. The prognosis of each variable adjusted for age was evaluated through Cox proportional hazard models and R2 percent (R2%) and V index (V6) were used as measures of the predictive accuracy of events of each of these variables. Receiver operating characteristic (ROC) curves from logistic regression models were used to determine the cut-offs for OUES and POUE.
RESULTS: pVO(2): 20.5±5.9; percentage of predicted peak VO(2): 68.6±18.2; VE/VCO(2) slope: 30.6±8.3; OUES: 1.85±0.61; POUE: 0.88±0.27. During a mean follow-up of 33.1±14.8 months, 45 (21.8%) patients died, 10 (4.9%) underwent urgent heart transplantation and in three patients (1.5%) a left ventricular assist device was implanted. All variables proved to be independent predictors of this combined event; however, VE/VCO2 slope was most strongly associated with events (HR 11.14). In this population, POUE was associated with a higher risk of events than OUES (HR 9.61 vs. 7.01), and was also a better predictor of events (R2: 28.91 vs. 22.37).
CONCLUSION: POUE was more strongly associated with death, urgent heart transplantation and implantation of a left ventricular assist device and proved to be a better predictor of events than OUES. These results suggest that this new parameter can increase the prognostic value of CPET in patients with CHF
Thoracic Fluid Content. A Possible Determinant of Ventilatory Efficiency in Patients with Heart Failure
A eficácia ventilatória, avaliada por prova de esforço cardiorrespiratória (PECR), tem um importante valor prognóstico em doentes (dts) com insuficiência cardÃaca crónica (ICC) por disfunção sistólica ventricular esquerda (DSVE). Os seus determinantes mantêm-se, contudo, controversos.
Objectivo: Investigar a eventual correlação entre parâmetros de eficácia ventilatória, obtidos por PECR, e o valor do fluido torácico total (FTT), avaliado por bioimpedância eléctrica torácica (BET), em dts com ICC por DSVE.
Métodos: Estudámos 120 dts com ICC por DSVE, referenciados ao nosso laboratório para
PECR — 76% do sexo masculino, idade 52,1 ± 12,1 anos, 37% de etiologia isquémica, fracção de ejecção ventricular esquerda 27,6 ± 7,9%, 83% em ritmo sinusal, 96% sob iECA e/ou ARAII, 79% sob beta-bloqueante e 20% tratados com dispositivo de ressincronização cardÃaca. Os dts efectuaram PECR, em tapete rolante, protocolo de Bruce modificado,sendo considerados para análise, como parâmetro de capacidade funcional, o consumo de oxigénio de pico (VO2p) e, como parâmetros de eficácia ventilatória, o declive (d) da relação entre ventilação minuto(VE) e produção de CO2 (VCO2) e o valor do VE/VCO2 no limiar anaeróbico (LANA). Os estudos
por BET, média de 20 minutos de aquisição, foram efectuados após 15 minutos de repouso, em posição supina, imediatamente antes das PECR, sendo analisado o valor do FTT.
Resultados: O valor do FTT variou entre 20,6 e 45,8 kOhm−1, média = 32,2, DP = 5,7, mediana = 32,7, o de VO2p entre 8,9 e 40,6 ml/kg/min, média = 21,0, DP = 6,2, mediana = 20,2, o do dVE/VCO2 entre 19,8 e 60,7, média = 30,7, DP = 7,9, mediana = 29,1 e o do VE/VCO2 no LANA entre 21 e 62,média = 33,1, DP = 7,5, mediana = 31,5. Por regressão linear, o FTT não se correlacionou com o VO2p — r = 0,05, p = 0,58 — mas apresentou correlação com os parâmetros de eficácia ventilatória analisados: r = 0,20, p = 0,032, r² = 0,04 com dVE/VCO2 e r = 0,25, p = 0,009, r² = 0.06 com VE/VCO2 no LANA.
Conclusão: O FTT correlaciona-se com os parâmetros de eficácia ventilatória, avaliados por PECR, em dts com ICC por DSVE, o que indica que poderá ser um dos seus determinantes
Left Atrial Volume: an Old Echocardiographic Measure with Renewed Prognostic Significance: a Study in Patients with Dilated Cardiomyopathy
Recentemente, surgiram alguns trabalhos que
ressaltaram a importância do cálculo do
volume da aurÃcula esquerda (VAE) como um
marcador de eventos cardÃacos adversos. Foi
objectivo deste estudo avaliar a importância
prognóstica deste parâmetro em doentes (dts)
com deficiente função ventricular esquerda e
correlacioná-lo com outros parâmetros
clássicos de prognóstico – consumo de O2
(VO2 max) e pro-BNP (pBNP).
Métodos: Analisou-se o volume da aurÃcula
esquerda (VAE) por método de Simpson, numa população de 35 dts com cardiopatia dilatada (idiopática e isquémica) com fracção de ejecção (FE) 31±9,6% doentes (dts) eram de sexo masculino e a média de idades foi de
50,5±10,5 anos. Toda a população efectuou
estudos de ecocardiografia convencional
(incluindo avaliação por M-mode, bidimensional e Doppler), prova cardiorespiratória (VO2max) e doseamento de
pro-BNP. O tempo médio de seguimento foi de
24 ± 4 meses, tendo-se considerado como
eventos cardÃacos (EC): internamento por
insuficiência cardÃaca, transplante e morte.
Resultados: Dos parâmetros da ecocardiografia
- o diâmetro da AE foi de 46,6±5,7mm, as dimensões do VE em diástole – 73,5±10mm e
em sÃstole -58,9±11mm, a média da fracção
de ejecção foi de 31±9,6%, o VAE foi de
78,6±33 ml, os volumes do VE foram de
214±82ml em diástole e de 153±75ml em
sÃstole, 15 dts tinham padrão restritivo de
enchimento ventricular (E/A>2), a média da
área (Doppler cor) da insuficiência mitral foi de 4±3,3cm2, 14 dts tinham E/E’>15. O VO2
max médio foi de 20±5,8ml/kg/min e o pro-BNP de 3146±4629pg/mL. Para além da correlação de outros parâmetros clássicos ecocardiográficos com o prognóstico (volumes
VE, FE e E/E’), o VAE e o volume indexado
da AE (VAE/SC) mostraram uma correlação
com o prognóstico (EC) com r=0,4 (p=0,02)
que não se verificou para o diâmetro da AE
(p=ns). Em relação à tolerância ao esforço,
houve uma correlação inversa entre o diâmetro, o volume e o volume indexado da
AE e o VO2max, com maior significado
estatÃstico para o VAE e VAE/SC com
r=-0,48, p=0,008. Quanto ao pro-BNP, quer o
diâmetro, quer o VAE (ou volume indexado)
tiverem o mesmo nÃvel de significado
estatÃstico (r=0,43; p=0,02). O valor predictivo de eventos (curvas ROC) para o VAE foi de 70ml e de 37ml/m2 para o VAE/m2.
Conclusão: O volume da aurÃcula esquerda/volume indexado é um parâmetro
ecocardiográfico com significado prognóstico
em dts com deficiente função ventricular
esquerda, correlacionando-se com a tolerância
ao esforço e pro-BNP
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