Computational Modeling for Surgical Reconstruction of Aortic Valve by Using Autologous Pericardium

Yong Feng,Huifeng Zhang,Yuqi Cao,Shengzhang Wang,Lai Wei,Bing Jia,Wenshuo Wang

doi:10.1109/access.2020.2997605

Abstract

The objective of this study was to evaluate the clinical effectiveness of surgical reconstruction of aortic valve using autologous pericardium, and the hemodynamic impact of matching the circumferential direction of the trimmed leaflet to inherent fiber orientation of the pericardium during surgery. A patient specific aortic valve model was built based on CTA data. The reconstructive surgery was carried out on the model following normal operating procedures. FSI simulation was performed to analyze the hemodynamic characteristics among the diseased model, normal model and three operative models with different misaligned angles between the circumferential direction of the substitute and inherent fiber orientation. The differences of EOA, velocity distribution, stress and strain on leaflets, and the valve deformation between the five models were compared and analyzed. The results showed that reconstructive surgery helps enlarge EOA, reduce abnormity of leaflet motion and blood ejection compared to diseased model. There was no significant difference between operative models with different misaligned angles in terms of leaflet motion and flow pattern, but as the misaligned angle increased, greater strain and deformation were observed on leaflets during the diastolic period. The present study demonstrated the instant clinical effectiveness of the reconstructive surgery of aortic valve by the improvement of EOA and flow pattern, and suggested that during the operation it may be unnecessary to match the circumferential direction of the substitute to inherent fiber orientation of the pericardium since the hemodynamic characteristics were insensitive to the fiber alignment, but the strain and deformation increment on the substitutes during diastolic period still raised concern about their durability.

Highlights

The aortic root comprises of three important structures, namely aortic sinus, leaflet, and aortic annulus
The present study reported an application of using immersed boundary method and computational simulation to study the effectiveness of the surgical reconstruction of aortic valve by using autologous pericardium, as well as potential improvement for the operative techniques
The instant clinical effectiveness of the reconstructive surgery of aortic valve got verified by comparison of kinematic and hemodynamic characteristics between the five models throughout the entire cardiac cycle, which showed that in the three operative models, the leaflets’ motion got back to normal, the effective orifice area (EOA) increased, and the velocity distribution of the blood flow within aorta became closer to a normal valve again

Summary

Introduction

The aortic root comprises of three important structures, namely aortic sinus, leaflet, and aortic annulus. The aortic sinuses are three anatomic dilations on ascending aorta right above the aortic valve, which allows the continuous blood supply to coronaries and help form vortices that assist the motion of aortic valve. The aortic annulus is a crown-shaped fibrous ring at the aortic orifice, which is part of the fibrous skeleton of the heart and connecting the leaflets. Aortic stenosis usually relates to the abnormality of the aortic ring and leaflets, which makes them clinically significant during the surgery [1], [2]. The anatomical morphology of each part of the aortic root and the coordinated changes during the cardiac cycles are the keys to its normal functioning [3], [4]

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