Abstract
This study was to evaluate the biomechanical characteristics of the vascular wall during virtual reality- (VR-) assisted percutaneous transluminal angioplasty (PTA) and its effect on the treatment of lower-extremity arteriosclerosis obliterans (LEAO). In this study, a three-dimensional (3D) model and a finite-element model of arteries were constructed first, and various fluid mechanics were analyzed. Then, the virtual expansion simulation (VES) of individualized PTA was performed based on the ABAQUS/Explicit module to analyze the interaction between the balloon and the blood vessel at different times and the changes in the vascular shape and structural stress distribution. Finally, an LEAO animal model was constructed. Based on conventional PTA (PTA group) and VR-assisted PTA (VR-PTA) treatment, the morphological changes of vascular lumen of the two animal models were evaluated. The results showed that the normal, stenotic blood vessels and blood models were successfully constructed; the pressure of the stenotic blood vessel at the stenosis decreased obviously and the shear stress of blood vessel wall increased compared with that of the normal blood vessels, and there may be a blood reflux area in the poststenosis stage. The simulation results of the VES showed that the maximum principal stress value at 3 mm of the marginal vessel was much lower than that at 5 mm (about 10% lower), so the maximum principal stress change within 2 mm of the balloon-expanded vessel was the most obvious. The treatment results of the animal model showed that the VR-PTA group showed an obvious increase in the diameter of the vascular lumen, a decrease in the intima and media area, and a decrease in the thickness of the vessel wall in contrast to the PTA group (P < 0.05), which had an important effect on the reconstruction and expansion of the vascular lumen. The VR-PTA treatment on LEAO was realized in this study, which provided critical reference for the follow-up application of VR technology in the evaluation of surgical plan and research on biomechanical mechanisms of restenosis after PTA.
Highlights
Atherosclerosis obliterans is one of the ischemic diseases with the highest incidence, and its prevalence is increasing year by year. e main manifestation of the disease is arteriosclerosis occlusion of the lower extremities, of which 30% occur in the iliac artery, and the other 70% are more common in the femoral artery, popliteal artery, and distal artery [1]. e clinical manifestations of arteriosclerosis occlusion of the lower extremities often show intermittent claudication, resting pain, and gangrene; and the severe progress of which may even affect the life safety of the patient [2]
It can only distinguish between soft plaques and calcified plaques but cannot quantitatively analyze the material properties of the blood vessel wall using the computed tomography angiography (CTA) technology. e patients with LEAO considered in this study were soft plaque lesions, so they were defined as a single vascular wall material property
A 3D model of normal arteries and stenotic arteries was constructed in this study. It showed that compared with the normal arterial blood vessel and blood model, the stenotic arteries and blood vessels showed obvious “torsion,” and the blood was consistent with the “torsion” of the stenotic vessels. erefore, “twisting” arteries were adopted in this study to simulate the stenosis of blood vessels
Summary
Atherosclerosis obliterans is one of the ischemic diseases with the highest incidence, and its prevalence is increasing year by year. e main manifestation of the disease is arteriosclerosis occlusion of the lower extremities, of which 30% occur in the iliac artery, and the other 70% are more common in the femoral artery, popliteal artery, and distal artery [1]. e clinical manifestations of arteriosclerosis occlusion of the lower extremities often show intermittent claudication, resting pain, and gangrene; and the severe progress of which may even affect the life safety of the patient [2]. PTA uses an inflation balloon to expand at the vascular stenosis to relieve the vascular stenosis, which can reduce the damage caused by the stent coating to the diseased blood vessel [6]. As PTA is prone to tearing of the vascular intima, and postoperative plaque prolapse, elastic retraction of the vessel walls, and vascular remodeling, it is easy to cause acute occlusion and restenosis of blood tubes, which largely limits its clinical application [10]. Both stent placement and bypass vessel grafting have higher surgical risks and higher surgical costs
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