Our story
CircAdapt began as a teaching tool: a way to help engineering and medical students develop an intuitive understanding of how the heart and circulation function as a single system. In this representation, the cardiovascular system has been composed of interacting building blocks: cardiac chambers, blood vessels, valves, and microvascular beds. Central to its development was the one-fibre model, introduced by Theo Arts in 1991, which describes how a cardiac chamber generates pressure and volume from the mechanical behaviour of a single representative muscle fibre. CircAdapt subsequently incorporated a physiological homeostatic principle: cardiac and vascular tissues adapt their geometry and mass to the mechanical load they carry, causing the model to self-organise. This adaptive principle gives the platform both its name and its distinctive character within the family of closed-loop cardiovascular models.
What began in the classroom grew into a primary research instrument. Under Joost Lumens and Tammo Delhaas, and with Theo Arts remaining closely involved, the model expanded in scope and depth, finding application across a wide range of cardiac diseases and their effects on cardiac function and on the circulation as a whole. Within the Department of Biomedical Engineering at CARIM, Maastricht University, it matured into a comprehensive research model capable of simulating complex physiological and pathophysiological scenarios across the entire cardiovascular system.
Where we are today
Nick van Osta has developed CircAdapt into a modular platform, in which cardiovascular models are assembled from interchangeable modules. This work marks the transition of CircAdapt from a single model into a true framework: a structured, documented, and extensible computational environment, developed with reference to verification and validation principles from ASME V&V40, that external academic researchers can adopt, scrutinise, and build upon. This transition is essential, as it makes the knowledge and modelling capabilities embedded in CircAdapt accessible and reusable beyond the originating group, rather than remaining confined to it. The same underlying model is available in two forms: pyCircAdapt, a Python package for in silico research, and CircAdaptUI, a graphical interface for teaching and exploration that requires no programming.
This modular architecture makes the platform extensible, and it continues to evolve under the joint coordination of Joost Lumens and Nick van Osta. New modules are in active development as CircAdapt advances with the field towards more detailed simulations, broader educational use, and patient-specific modelling.
Open science
CircAdapt reflects an open and transparent approach to science: its methods and source code are open to inspection, reproduction, and extension by the research community. Developed at the CARIM Cardiovascular Research Institute Maastricht of Maastricht University, it is an academic platform rather than a commercial product, with no vendor, subscription, or paywall. CircAdaptUI can be downloaded at no cost, and the framework source code is available to registered academic researchers under the CircAdapt Framework licence, a tailored academic-use licence that permits use for research and education with attribution. The scientific foundation of CircAdapt is documented in our key publications.
Why choose CircAdapt?
Academic Foundation
Developed and maintained by cardiovascular researchers at the Cardiovascular Research Institute Maastricht (CARIM) of Maastricht University
Physiology-Based
Grounded in fundamental physiological principles rather than simplified empirical relationships
Multi-scale Integration
Seamlessly connects tissue, organ, and system-level cardiovascular function
Validated Approach
Based on methods published in peer-reviewed scientific literature
Open Science
Freely available, open-source resources that advance scientific collaboration
Active Development
Continuously improved through academic research and collaboration
Mission
To advance cardiovascular research and education by providing open, physiology-based simulation tools that deepen understanding of cardiac and circulatory function in health and disease.
Vision
To establish physiology-based computational modelling and simulation as an integral instrument of cardiovascular research, education, and clinical reasoning. A distinctive feature of the CircAdapt viewpoint is parsimony: for any given research question, we seek the minimal model complexity (i.e., the smallest number of parameters) that preserves physiological validity across the widest possible range of conditions. This pursuit of parsimony is what gives CircAdapt both its interpretability and its broad applicability. In CircAdapt, simplicity is the sophistication.