11. A federated platform for cardiovascular simulation services

Rosa M. Badia, Pablo J. Blanco, Carlos Diaz, Antônio Tadeu A. Gomes, Daniele Lezzi, Alfonso Santiago, Mariano Vazquez
Focus area: 
Federated cloud infrastructures for research and science. EU-Brazil Cooperation
Who stands to benefit and how: 
The implementation of the cardiovascular simulation platform has impact on several stakeholders including cardiologists and researchers who collaborate with them to provide advanced modelling solutions. Cardiologists will benefit from a set of tools that allow to obtain a better understanding of the phenomena involved in the interaction between the cardiac dynamics and systemic conditionsthrough the simulation of different scenarios. On the other side the researchers will benefit from the extension of the capabilities of two existing modellers: Alya Red and ADAN, to create new models with increased scientific relevance. Future uptake of the simulation environment includes the integration within the Hemodynamic Modelling Laboratory (HeMoLab), which is an online tool for the simulation of the human cardiovascular system developed by LNCC, and within a BigData visualization tool developed by the Computer Applications in Science and Engineering (CASE) department at BSC.
Focus of your position paper: 
The heartbeat is a phenomenon that involves several scales and different problems that are tightly coupled. This means that diverse orders of magnitude are linked, from the microscopic cell arrangement into a spatial description, to the macroscopic shape of the cardiac chambers. Also, different types of physical problems are involved: the propagation of the electrical stimuli in the cardiac myocites; the contraction of these cells that produces the deformation of the macroscopic geometry; and the effect of this contraction in the fluid contained on the chambers including the reciprocal force of the fluid against the walls of the cavity. Thus, we can say that the heartbeat is an electromechanical phenomenon in which the mechanical part involves a fluid-structure interaction (FSI) problem. In turn, the circulation of blood in the arteries is also an FSI problem resulting from the pumping effect of the cardiac muscle driving the blood flow through deformable vessels. Because of the scales involved, this becomes a wave propagation problem in which pressure and flow waveforms travel throughout the system. EUBrazilCC leverages the integration of heterogeneous supercomputing and virtualized infrastructures with the orchestration, through the components integrated in the platform, of two simulation codes from Brazil and Spain, addressing the two complementary problems of Cardiac Electromechanical Modelling and Arterial Blood Flow Modelling. The simulation platform for the cardiac model is Alya, which is BSC’s in-house simulation tool. Alya System is a Computational Mechanics code with two main features. Firstly, it is specially designed for running with high efficiency standards in large-scale supercomputing facilities. Secondly, it is capable of solving different physics in a coupled way, each one with its own modelling characteristics: fluids, solids, electrical activity and others. LNCC has developed an Anatomically-Detailed Arterial Network (ADAN) model starting from anatomical data and physiological concepts in order to perform cutting-edge cardiovascular research supported by modelling of physical phenomena and simulation-based techniques. Among other features, ADAN incorporates, in the definition of the vascular topology, most of the arteries which are acknowledged in the medical and anatomical literature for an average male. The integrated simulation environment includes two deployment scenarios on the Federated EUbrazil-Cloud Connect infrastructure: the execution of parametric runs on a cloud infrastructure and the execution of coupled runs of high definition simulations on distributed HPC resources. For the cloud implementation, an application has been developed using the BSC COMPSs Programming Framework, to orchestrate the execution of the AlyaADAN coupled simulator. High definition runs use HPC resources at BSC and LNCC coordinated by the CSGrid middleware, and the coupling is obtained through a connector in the cloud that regulates information flow between the two models over the network and across organization boundaries. The mc2 platform provides a common user interface for these different types of runs. Without the Infrastructure developed within the EUBrazil Cloud Connect project, the described scenarios could never have been realized. The architecture used for the parametric studies is essential to understand the physiological behavior of the intrinsic processes of the heartbeat. Also, the distributed high definition runs of Alya and ADAN will led to the most complex and complete model of the cardiovascular system to this moment.