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Detalhes

Detalhes

  • Nome

    Argentina Leite
  • Cargo

    Investigador Colaborador Externo
  • Desde

    01 janeiro 2014
  • Nacionalidade

    Portugal
  • Contactos

    +351222094106
    argentina.leite@inesctec.pt
Publicações

2022

How can we predict the kidney graft failure of Portuguese patients?

Autores
Cerqueira, S; Campelos, MR; Leite, A; Pires, EJS; Pereira, LT; Diniz, H; Sampaio, S; Figueiredo, A; Alve, R;

Publicação
REVISTA DE NEFROLOGIA DIALISIS Y TRASPLANTE

Abstract
Background: The gap between offer and need for a kidney transplant (KT) has been increasing. The Kidney Donor Profile Index (KDPI) is a measure of organ quality and allows estimation of graft survival, but could not apply to all populations. Knowledge of our kidney donor and recipient population is vital to adjust transplant strategies. Methods: We performed a retrospective evaluation of donors and recipients of KT regarding two kidney transplant units: Centro Hospitalar Universitario de Coimbra, CHUC (Coimbra, Portugal) and Centro Hospitalar Universitario de Sao Joao, CHUSJ (Porto, Portugal), between 2013 and 2018. We then did statistical analysis and modeling, correlating these KT outcomes with donor and recipient characteristics, including KDPI. Artificial intelligence methods were performed to determine the best predictors of graft survival. Results: We analyzed a total of 808 kidney donors and 829 recipients of KT. The association between KDPI and graft dysfunction was only moderate. The decision tree machine learning algorithm proved to be better at predicting graft failure than artificial neural networks. Multinomial logistic regression revealed recipient age as an important prognostic factor for graft loss. Conclusions: In this Portuguese cohort, KDPI was not a good measure of KT survival, although it correlated with GFR 1 year post-transplant. The decision tree proved to be the best algorithm to predict graft failure. Age of the recipient was the most important predictor of graft dysfunction.

2021

Effects of inlet velocity profile on the hemodynamics of the abdominal aorta bifurcation

Autores
Soares, AA; Carvalho, FA; Leite, A;

Publicação
JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING

Abstract
In this paper, a numerical study is conducted to investigate the influence of imposed inlet velocity profile on the hemodynamics in the region of the abdominal aorta bifurcation, for a patient specific. The influences of two different inflow velocity profiles on the hemodynamics of the abdominal aorta bifurcation have been investigated. The simulations were carried out under the same conditions changing only the shape of the inlet velocity profile in abdominal aorta. The simulations were performed with a parabolic profile (PP) and a uniform profile (UP) to quantify the hemodynamic differences between them, in the arterial regions, that is, in the upstream bifurcation, in the bifurcation and downstream bifurcation in each of the common iliac arteries. The results reported provide fundamental knowledge to a better understand of the inflow velocity profiles influence in the hemodynamics of the abdominal aorta bifurcation, such as the distribution of the velocity, pressure and wall shear stress (WSS), as well as the distribution of the stress hemodynamic descriptors on the artery wall. The results highlighted that the influence of the inlet velocity profiles in the time-averaged wall shear stress (AWSS) and relative residence time (RRT) is not significant after the abdominal aorta bifurcation. In general, for the hemodynamic descriptors studied, the correlation between the results obtained with the two velocity profiles reaches values close to 1 in the iliac arteries, in contrast to the abdominal region, where the correlation is less than 0.6.

2021

Automatic Fall Detection Using Long Short-Term Memory Network

Autores
Magalhaes, C; Ribeiro, J; Leite, A; Pires, EJS; Pavao, J;

Publicação
ADVANCES IN COMPUTATIONAL INTELLIGENCE, IWANN 2021, PT I

Abstract
Falls, especially in the elderly, are one of the main factors of hospitalization. Time-consuming intervention can be fatal or cause irreversible damages to the victims. On the other hand, there is currently a significant amount of smart clothing equipped with various sensors, particularly gyroscopes and accelerometers, which can be used to detect accidents. The creation of a tool that automatically detects eventual falls allows helping the victims as soon as possible. This works focuses in the automatic fall detection from sensors signals using long short-term memory networks. To train and test this approach, the Sisfall dataset is used, which considers the simulation of 23 adults and 15 older people. These simulations are based on everyday activities and the falls that may result from their execution. The results indicate that the procedure provides an accuracy score of 97.1% on the test set.

2021

Wall Shear Stress-Based Hemodynamic Descriptors in the Abdominal Aorta Bifurcation: Analysis of a Case Study

Autores
Soares, AA; Carvalho, FA; Leite, A;

Publicação
JOURNAL OF APPLIED FLUID MECHANICS

Abstract
The knowledge of hemodynamic behaviour in the abdominal aorta artery bifurcation is of great importance for the early diagnosis of several cardiovascular diseases common in this bifurcation. The work developed focuses on a case study of hemodynamic in the abdominal aorta artery bifurcation, based on a realistic 3D geometric model reconstructed from 2D medical images of a real patient. Hemodynamic quantities based on the wall shear stress (WSS) of the abdominal aorta bifurcation are analysed and is presented an alternative analysis of the well-established stress hemodynamic descriptors to identify specific zones of the artery with a higher probability of developing cardiovascular diseases. The individual analysis of different zones of the artery allowed to obtain information that can remain masked when whole artery is considered as a single zone. The reported results provide a correlation between the analysed stress hemodynamic descriptors and the area of the wall artery. Then, the aim of this work is the identification of regions at the luminal surface subject to atherosusceptible WSS phenotypes. For the patient studied, the analysis presented allowed the identification of the patient's propensity to develop atherosclerosis, according to the hemodynamic descriptors time-averaged WSS (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT). Thus, this work offers a new way of looking to the stress hemodynamic descriptors.

2021

Classification of cardiovascular signals

Autores
Saraiva T.; Leite A.; Solteiro Pires E.J.; Faria R.;

Publicação
2021 IEEE Latin American Conference on Computational Intelligence, LA-CCI 2021

Abstract
Congestive heart failure (CHF) is a severe condition that affects the pumping power of your cardiac muscle. In this work, long-term memory (LSTM) and Bidirectional LSTM (BiLSTM) networks were used to identify congestive heart failure human beings using datasets from the PhysioNET. Two approaches were adopted, the first considers beating signals directly to feed the LSTM networks, and the second one used features signals extracted from the beating signals. The BiLSTM considering features signals obtain the best results reaching an accuracy of 90%.

Teses
supervisionadas

2017

Hemodinâmica da bifurcação da Artéria Aorta Abdominal: Análise de indices hemodinâmicos

Autor
Filipa Daniela Alves Carvalho

Instituição
UTAD

2017

Estudo de sinais de ECG de indivíduos sujeitos a situações de stress

Autor
Pedro Mauricio Pimenta Sampaio

Instituição
UTAD

2017

Análise da variabilidade da frequência cardíaca em indivíduos saudáveis e doentes

Autor
Cristina Monteiro Pinto

Instituição
UTAD

2017

Análise da variabilidade da frequência cardíaca usando métodos não lineares

Autor
Hugo Machado

Instituição
UTAD

2016

Influência dos harmónicos de Fourier do batimento cardíaco na hemodinâmica da bifurcação da Artéria Aorta Abdominal

Autor
Filipa Daniela Alves Carvalho

Instituição
UTAD