Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Exergy Analysis of the Heart with a Stenosis in the Arterial Valve

Full text
Author(s):
Roll, Julio Brandao [1] ; Borges, Matheus Leone [2] ; Keutenedjian Mady, Carlos Eduardo [2] ; de Oliveira Junior, Silvio [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Polytech Sch, Av Luciano Gualberto 380, BR-05508010 Sao Paulo - Brazil
[2] Univ Estadual Campinas, Sch Mech Engn, Mendeleyev St 200, BR-13083970 Campinas, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Entropy; v. 21, n. 6 JUN 2019.
Web of Science Citations: 1
Abstract

In the past decade, several articles have proposed the use of an exergy perspective to analyze physiological systems of the human body under different physical conditions. Such a perspective focuses on the exergy transformations and the efficiency of the biological processes. This may aid the medical field in assessments of a patient's physical health by means of an index (exergy efficiency) based on the quality of the energy conversion in a given process within the human heart. As a follow-up, a model was developed to describe the evolution of the transvalvular pressure gradient in the aortic valve as a function of stenosis severity. This model was created using physiological data from 40 patients available in the literature, as well as 32 operating points from different bileaflet aortic valve prosthesis. A linear regression results in values around 14.0 kPa for the pressure gradient in the most severe case, evolving from 1.0 kPa for a healthy scenario. The thermodynamic model assesses the irreversibilities associated with energy conversion processes related to metabolism: exergy destroyed at the valves, exergy increased in the flow, and the power of the heart. Results indicate that destroyed exergy reaches values of 10 W (almost 10% of total basal metabolic rate of the whole body). Exergy efficiency is 15% for a healthy heart, decreasing as a function of the severity of the stenosis to values lower than 5%. (AU)

FAPESP's process: 15/22883-7 - Thermodynamics analysis applied to biological systems
Grantee:Carlos Eduardo Keutenedjian Mady
Support Opportunities: Regular Research Grants