Concept of the computer model

The patient’s physiological status can be described by a computer model, with two important consequences:

  1. The model can provide quantitative measures that are able to characterise the physiological status and contribute to diagnosis.

  2. Changes in the components of the system, or of the ‘forces’ on the system, are reflected in physiological changes that can be predicted by operation of the model. The effects of prospective interventions can be simulated.

It is assumed that there is an association between the physiological status and the biological response, including for example the modelling and remodelling of the heart under the loads that it generates and to which it is subjected.

This biological response might be described by specific pathways and mechanistic models, or it might be evaluated in terms of individual propensity to particular outcomes based on population studies.

The computational models at the core of this project are a series of published compartmental models that describe the distribution of flow and pressure in the cardiovascular system, combined with anatomically accurate models based on 3D and 4D imaging of the patient.

Specifically for the diagnosis of heart valve disease and for valve interventional planning it is important to be able to assess the pressure gradient across the valves, any leaks through the valves (the focus is on mitral and aortic valves) and their contribution to the loads on the chambers of heart and its effectiveness in supplying blood to the circulation.

It should be emphasised that the novelty of this proposal lies not in the computational models (the partners have strong established expertise in all aspects of these models) but in the combination of these models with the heterogeneous clinical and population data.

Multi-level circulation model

The model is fundamentally multilevel.

The region of the valve is described in anatomical detail, based on the medical image of the patient.

The circulation is described in terms of compartmental electrical analogue models that are able to represent the variations of pressure and flow throughout the system as a function of the compliance and impedance of the vessels.

The figure indicates which of the anatomical elements is represented by each part. A specific implementation of the digital patient that includes all data, measured or derived, that is relevant to this patient, and to this disease process, will be developed.