10 Sep Hierarchical VVUQ Strategy

Introducing a Hierarchical VVUQ Strategy for Biodegradable Pulmonary Heart Valve Development

One of the key tasks of the EU-funded SimInSitu project is to establish model credibility for biodegradable heart valves. To achieve this, we implemented a hierarchical VVUQ (Verification, Validation, and Uncertainty Quantification) approach to develop a credible patient-specific in-silico finite element model (FEM). This strategy spans seven levels of complexity, ensuring a robust and reliable model tailored to individual patients.

In today’s post, we will describe the medical device and the Hierarchical VVUQ Approach. Over the coming weeks, we will release a series of blog posts detailing our progress and methodologies:
1 Medical Device and Hierarchical VVUQ Approach: Introducing the pulmonary heart valve device and our hierarchical strategy for establishing model credibility.
2 Material Level: Focusing on the first level of the VVUQ pyramid, discussing material characterization and constitutive modeling.
3 Single Device Component Level: Examining the modeling, verification, and validation of individual device components.
4 Complete Device Level: Detailing the assembly of the complete device and the rigorous testing involved to ensure its functionality and reliability.

Pulmonary Heart Valve Description

A biodegradable pulmonary valve (PV) represents an innovative advancement in medical technology. This surgical heart-valve substitute consists of a conduit and three leaflets, each crafted from distinct scaffold materials using electro-spinning. This process creates a highly porous structure that facilitates biodegradation and native tissue regeneration.
The pulmonary valve is made from a synthetic polymer with a specific architecture. Upon implantation in the human body, it undergoes a biological process known as cell infiltration. During this process, the polymer gradually degrades while simultaneously promoting the generation of new cell tissue. Over the course of one to two years, this scaffold is completely replaced by the patient’s native tissue. Below you can find a pulmonary valve developed by Xeltis, which has been an important SimInSitu driver.

Hierarchical VVUQ Approach

Alongside the technological challenges during the SimInSitu project, we tackled another critical issue: the credibility of in-silico tests.
We used a hierarchical VVUQ approach to build the FEM model bottom-up. There are seven complexity levels worked out in the SimInSitu project, which are shown below. At each complexity level verification, validation, and uncertainty quantification activities were conducted. As described before, in these blog posts we will focus on the first three levels. At the material model level, also calibration activities were conducted. Uncertainty factors that were identified as significant at a lower level were propagated to the higher complexity level and were considered at that stage in the UQ assessment as well. We followed the well-established ASME V&V standards.

Stay tuned for our next post, where we will dive into the material level of the hierarchical VVUQ approach.
Next blog post: Material level Hierarchical VVUQ Strategy