3D printed cardiac phantom for procedural planning of a transcatheter native mitral valve replacement

Abstract

3D printing an anatomically accurate, functional flow loop phantom of a patient’s cardiac vasculature was used to assist in the surgical planning of one of the first native transcatheter mitral valve replacement (TMVR) procedures. CTA scans were acquired from a patient about to undergo the first minimally-invasive native TMVR procedure at the Gates Vascular Institute in Buffalo, NY. A python scripting library, the Vascular Modeling Toolkit (VMTK), was used to segment the 3D geometry of the patient’s cardiac chambers and mitral valve with severe stenosis, calcific in nature. A stereolithographic (STL) mesh was generated and AutoDesk Meshmixer was used to transform the vascular surface into a functioning closed flow loop. A Stratasys Objet 500 Connex3 multi-material printer was used to fabricate the phantom with distinguishable material features of the vasculature and calcified valve. The interventional team performed a mock procedure on the phantom, embedding valve cages in the model and imaging the phantom with a Toshiba Infinix INFX-8000V 5-axis C-arm bi-Plane angiography system. Results After performing the mock-procedure on the cardiac phantom, the cardiologists optimized their transapical surgical approach. The mitral valve stenosis and calcification were clearly visible. The phantom was used to inform the sizing of the valve to be implanted. Conclusion With advances in image processing and 3D printing technology, it is possible to create realistic patient-specific phantoms which can act as a guide for the interventional team. Using 3D printed phantoms as a valve sizing method shows potential as a more informative technique than typical CTA reconstruction alone.

3D printed cardiovascular patient specific phantoms used for clinical validation of a CT-derived FFR diagnostic software

“…The inner lumen was combined to the solid mesh to form a hollow 3D printable vasculature. 1,6,8 The inlets and outlets of the model were finally cut to allow for interior flow immersion (Figure 4d). …”

3D printed abdominal aortic aneurysm phantom for image guided surgical planning with a patient specific fenestrated endovascular graft system

“…The final step was to apply a standard marching cubes algorithm on the zero-level to construct a triangulated surface model of each component, which were individually written out to stereolithographic (STL) files for use in later steps. For a detailed overview of the segmentation methods employed here, please refer to our lab’s prior publication [24] .…”

Cardiothoracic Applications of 3-dimensional Printing

“…As more functionally accurate 3D printing becomes a reality, device testing and minimally invasive procedure simulations will follow. At present we are considering the use of experiments with flow in the printed models under fluoroscopy to help prepare for transcatheter mitral valve replacement [64]. In the future, patient-specific annuloplasty devices and prosthetic heart valves could become a possibility [65].…”