Vascular Reconstruction is one of the most challenging areas of surgery, the surgeon has to create a completely watertight reconstruction without any narrowing or deformity that will restore normal flow characteristics, even at high pressures. Nowhere is this more challenging than in neonatal heart surgery where babies born with aortic arch narrowing or underdevelopment are one of the commonest life-threatening cardiovascular conditions.

Reconstruction not only has to recreate normal anatomy but also allow for subsequent growth and development.

Until now, surgical reconstruction depended on the surgeon's subjective assessment of the anatomy and a best estimate of patch shaping and design. New engineering techniques have enabled us to create 3D printed models of real hearts and then recreate the actual surgery on these models using a variety of engineered patches and different surgical techniques. These reconstructed models can now be placed in flow-testing rigs and undergo 4-dimensional flow imaging to provide high-fidelity velocity and shear force analysis that allow for precision design of the ideal geometry to give optimal flow.

This project will combine the skills of the largest team of neonatal heart surgeons in Canada, working with cardiac imaging experts, physicists and biomechanical engineers who are recognized as the world leaders in 3D printing technologies for congenital heart disease. Using a series of rigorous repeated tests and different designs we will define the ideal techniques and patch shapes and then translate this to real cases where a precision-shaped personalized patch can be created for each individual. Following up these babies as they grow with precision 3D scanning will show how these vessels are growing. Our mathematics-driven approach will make the surgery easier, shorter and more efficient. It will also provide more consistent surgical results among surgeons.

Aortic arch reconstruction complications can be prevented or minimalized by personalizing the surgical technique and patch through mathematical computer modeling and 3D printing.

This is a feasibility study on the use of graphical 3D printing and flow modelling in the creation of personalized patch templates for the Norwood procedure and aortic arch reconstruction.

Patients undergoing the Norwood procedure as part of standard of care will be approached for consent. Patients who consent to the study will undergo a pre-operative contrast CT scan to design simulation models and to identify the most ideal aortic arch configuration. 3D printing of the sterilizable template will be done after computer-aided design of bespoke surgical patches and will be based on pre-operative imaging and simulation. The sterilizable patch template will be used by the surgeon as a guide to fashioning the precise size and shape of the patch.

A research CT scan will be done post-operatively, prior to patient discharge. The post-op CT scan will be used to create a 3D printed model of the reconstructed aortic arch, This 3D printed model will then undergo 4D MRI scanning as part of the analysis.

Patients will be monitored and followed closely post-surgery. They will be assessed by routine post-operative tests including standard of care imaging at 4-6 months after surgery.

Clinical outcome assessment at 6-12 months after surgery will be measured.

This data will be compared to surgical outcomes of a historical cohort of patients who had traditional patches.

Inclusion Criteria:

• Newborns, 0-2 months of age
• Requiring a Norwood procedure and aortic arch reconstruction
• Consent provided

Exclusion Criteria:

• Consent not provided
• Contraindications to contrast CT scans (allergy to contrast, kidney disease)
• Any condition or diagnosis, that could in the opinion of the Principal Investigator or delegate interfere with the participant's ability to comply with the study, might confound the interpretation of the study results, or put the participant at risk