VIRTUAL SIMULATION OF TRANSCATHETER AORTIC VALVE IMPLANTATION Jenna Smetana and Jessica Sider, Swanson School of Engineering THE TAVI PROCEDURE IS FEASIBLE The use of finite element framework and virtual simulation is a breakthrough for the medical world, allowing the TAVI procedure to be conducted at optimal safety and efficiency, which is the ultimate goal of any risky operation. Through the use of these methods, patients have the ability to know exactly what is going to take place during their surgery and how their bodies are going to react. More than ever, TAVI is proving to be an effective alternative to open heart surgery, and the results support a positive outlook on the future of the treatment of aortic stenosis. This picture shows what is expected to happen when the implant is inserted into the aortic root in the case of these two patients. The different colors depict different levels of stress in certain areas. Simulations such as this help doctors to understand how different patients are going to be affected by the TAVI procedure. As the colors in the picture show, different types of patients will experience different complications. WHAT IS AORTIC STENOSIS? The aorta is the largest artery in the body and is the main valve that carries blood out of the heart, through the left ventricle, and to the rest of the body. In aortic stenosis, the aortic valve narrows, and blood flow from the heart is decreased. If the aortic valve does not open fully, the left ventricle is forced to work harder to pump blood out through the valve. This causes the muscles of the left ventricle walls to become thicker and the pressure in the heart will continuously rise. Severe aortic stenosis “can limit the amount of blood that reaches the brain and the rest of the body. When left untreated, as many as fifty percent of patients [suffering] will not survive more than an average of two years after the onset of symptoms. THE TAVI PROCEDURE Replacement of the aortic valve remains an effective treatment, but the complications from open-heart surgery decreased the interest and popularity of this method. The introduction of the TAVI procedure allowed the replacement of the aortic valve in a more successful, less complicated manner. Catheter-based aortic valve implantation has shown promising results in providing treatment options for patients with severe aortic stenosis who are poor open surgical candidates. There are two catheter-based aortic valves that have been used in human trials. The CoreValve and the Edwards Sapien valve have been implanted in the human body through the transapical placement through a direct apical puncture and the retrograde transfemoral approach through the femoral artery STEPS TO SIMULATING THE TAVI PROCEDURE HOW CAN TAVI BE IMPROVED? Safety, reliability, and efficacy are the key issues to address when promoting the TAVI procedure over traditional open-heart surgery. While its procedural risks differ from the original method, improvements for the design of the devices and implantation techniques are required to improve the success rate of TAVI, reduce hospital stay and rehabilitation, and decrease the rate of morbidity among high risk patients. The adopted computational framework to simulate the TAVI procedure can be divided into four main steps: processing of medical images, creation of analysis-suitable models, performance of all the required analyses to reproduce the entire clinical procedure, and post-processing of the simulation result and comparison with follow-up data. Medical imaging involves computed tomography data and 2D echo data. Analysis-suitable should include the aortic sinuses, native leaflets, calcifications, and the prosthetic device. Analysis of the process must include stent crimping, stent expansion, valve mapping, and valve closure. Post- processing will analyze the simulation output and follow-up data. The combination of these steps will provide physicians with a more accurate idea of how the specific patient will respond to the transcatheter aortic valve implantation procedure. STEP DESCRIPTION CREATION OF STENT MODEL CREATION OF THE AORTIC ROOT MODEL net of the stent created with Rhinoceros software v 4.0 geometry obtained from splines of STL file geometry is mirrored and replicated to unfold the geometry of the stent. 3D reconstruction of multi- detector computed tomography (MDCT) and magnetic resonance (MR) imaging of aortic root Two dimensional echocardiography PREPROCEDURAL COMPUTED TOMOGRAPHY provides clinicians with accurate view of whether patient can handle TAVI procedure detects dimensions of aortic root, degree of valve calcification, and morphology of access roots