סמינר מחלקה של עומר טל - ביומכניקה של מסתמי אבי העורקים מסויידים: מודלים חזויים של גדילה וניתוח מכני של תיקון TAVI

21 ביוני 2023, 14:00 - 15:00 
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סמינר מחלקה של עומר טל - ביומכניקה של מסתמי אבי העורקים מסויידים: מודלים חזויים של גדילה וניתוח מכני של תיקון TAVI

 

School of Mechanical Engineering Seminar
Wednesday June 21.6.2023

Wolfson Building of Mechanical Engineering, Room 206

 

Biomechanics of Calcified Aortic Valves:  Predictive Growth Models and Mechanical Analysis of TAVI Repair

 

Omer Tal

 

M.Sc. research under the supervision of Prof. Rami Haj-Ali Tel Aviv University, Department of Mechanical Engineering

 

 

The aortic valve (AV) is one of four heart valves and is the final one encountered by oxygenated blood as it leaves the heart. It is responsible for preventing the backflow of oxygen-rich blood from the aorta into the left ventricle during diastole. Aortic stenosis (AS) is the most prevalent of all valvular heart diseases in developed countries. Roughly 25% of people over 65 have AV thickening and 3% over 75 have severe stenosis. AV calcification refers to the inflammation and remodeling of the extracellular matrix, resulting in the formation of bone-like structures on the valve. Calcified AS is the leading cause of valve replacement in developed nations. More than 50% of patients diagnosed with AS have bicuspid aortic valves (BAV), and their disease progression rate is accelerated compared to patients with a tricuspid aortic valve (TAV). Transcatheter Aortic Valve Implantation (TAVI) is a minimally invasive procedure used to replace a damaged AV without open-heart surgery. Since its introduction in 2002, TAVI has become an increasingly preferred alternative to surgical aortic valve replacement.

This study presents a validation and extension of the theoretical framework of the Reversed Calcification Technique (RCT) previously proposed in our Lab. RCT enables the reconstruction of patient-specific aortic valve calcification progression, aiming to encompass the timeline from initiation to the current state. Notably, this study incorporates a time scale into the RCT theory, transforming it into a robust quantitative method capable of reconstructing calcification morphology and quantifying calcification volume at any relevant time in the past. Two approaches are introduced and rigorously validated. The RCT is utilized to provide a clinically relevant and realistic simulation of calcification growth in bicuspid aortic valves. To assess the impact of calcification distribution on valve biomechanics and transcatheter aortic valve implantation (TAVI) outcomes, finite element analyses are conducted by integrating RCT with a group-specific calcification modeling technique. By dividing the bicuspid aortic valve calcification into regional calcification, precise control over calcification distribution is achieved by manipulating regional calcification growth stages. Multiple valve calcification distributions are simulated with critical parameters, including pre-and post-TAVI valve area, maximal stresses on the valve, and anchoring forces. The extended RCT method is quantitative and capable of predicting the total volume growth of different TAV and BAV patents (n=14) with an average error of 15% from multiple CT over a maximum time interval of 5 years. Combining RCT in BAV to perform TAVI simulations at different calcification stages can serve in the patient-specific design of future repair therapy. This study advances our understanding of calcified bicuspid aortic valves and offers valuable insights for optimizing TAVI procedures.

Join Zoom Meeting https://tau-ac-il.zoom.us/j/86497933118

 

 

 

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