The research conducted in the VIBE lab involves all vasculature of the human body – from the heart to all the way to fingers and toes. Scroll through this page to explore some of our projects starting with an overview of our modeling methodology.
Modeling of the Cardiovascular System
As illustrated in the short video to the right, our modeling protocol starts from medical imaging such as CT or MRI, and using SimVascular (https://simvascular.github.io), 3D models of the vessels are constructed. Based on these models, we can apply custom software and methodology to investigate our hypotheses related to motion of vessels (and implants) linked to physiological phenomena such as cardiac pulsatility, respiratory-induced deformation, or musculoskeletal movement.
Biomechanical Response of Stented Carotid Arteries to Swallowing and Neck Motion
The carotid artery swings in the medial direction dramatically during swallowing motion. This motion causes cyclic bending of carotid artery stents, potentially causing stent fatigue and fracture. The stent is especially vulnerable at the location of strain concentration at the transition from common carotid to internal carotid artery.
Deformations of the Thoracic Aorta and Branches Due to Respiration and Cardiac Pulsatility
Quantification of cardiac and respiratory motion of diseased thoracic aortas is critical for the design and evaluation of thoracic aortic endografts and thoracic branch devices. While historically, durability testing has been focused on cardiac motion, respiratory motion causes much larger superior-inferior and anterior-posterior translations of the arch.
Influence of Endografts on Thoracic Aortic Anatomy and Respiratory- and Cardiac-Induced Motion
The added stiffness of thoracic aortic endografts affects the geometry and dynamic behavior of the native anatomy. These influences may in turn affect the aortic physiology and long-term performance of these devices.
Type B dissection chirality and
Thoracic aortic dissections often follow a helical (corkscrew shape) path. Interestingly, when follow a helical path, they are always right-handed chiral and create a helical angle that is nearly 180 degrees. This means thoracic aortic dissections do not exhibit left-handed chirality or intermediate levels of helicity. These consistent and asymmetric properties have many implications for interventional technique and device design.
Coronary Artery Biomechanics and Influence on Coronary Stent Performance
There are significant morphologic changes of the coronary arteries, left ventricle, and myocardium during the cardiac cycle. These dynamic conditions affect coronary artery stent performance, both in terms of stent durability performance and arterial irritation or injury.
Biomechanics of the Left Atrial Appendage and Influence on Devices
The left atrial appendage is a common site of thrombus formation in patients with atrial fibrillation. Dislodged blood clots from the LAA can cause strokes, so in high-risk patients, LAA occlusion can be used to prevent embolic strokes. Quantification of cardiac deformation of the LAA volume and orifice shape can be useful in the design and evaluation of LAA occlusion devices.
Patent Ductus Arteriosus Stenting
Neonates with ductal-dependent pulmonary circulations require the patent ductus arteriosus (PDA) to remain open to transfer blood from the aorta to the pulmonary circulation for reoxygenation. A minimally-invasive technique to achieve this is percutaneous stenting of the PDA. The amount of straightening and shortening of the PDA due to stenting is critical for procedure planning and de novo design of PDA-specific stents.
Comparison of Biomechanics and Clinical Outcomes Between Snorkel and Fenestrated AAA Endovascular Repairs
Pre-operative CTs (left column), post-operative CTs (middle column), and post-operative 3D models (right column) of snorkel (top row) and fenestrated (bottom row) endovascular AAA repairs. The use of snorkel and fenestrated grafts in conjunction with AAA stent grafts are used for visceral perfusion. However, selection criteria for these branching options are not well defined and their long-term performance may be influenced by biomechanical factors.
Visceral Artery Geometry and Respiratory-Induced Deformation in Patients with AAA
The celiac, superior mesenteric, and renal arteries are subject to deformation due to the dynamics of the diaphragm during respiration. The visceral arteries move inferiorly during inspiration because the descending diaphragm pushes the visceral organs downward. These motions impact the performance of visceral artery stents and branched aortic stent-grafts.
Iliofemoral Venous Stent Deformations
Thrombotic and non-thrombotic iliofemoral venous disease can be treated with venous stents. However, these stents are subject to cyclic axial, bending, and compression deformations that may cause device fatigue. Iliofemoral veins (light blue) overlaid with iliofemoral arteries (pink), L5 vertebral body (gray), and inguinal ligament paths (gray thin cylinders) in states of pre-stenting (left), post-stenting (middle), and with three different hip flexion angles (right – red, yellow, dark blue).
Deformations of the Abdominal Aorta and Iliac Arteries During Hip Flexion
Hip flexion causes bending and shortening of the abdominal aorta and iliac arteries by releasing tension in the arteries. These deformations should be considered in the design and evaluation of stents and stent-grafts implanted into these anatomies.
Femoropopliteal Artery Biomechanics With Joint Flexion
The femoropoliteal arteries undergo substantial axial, twist, and bending deformations during hip and knee flexion. This means that normal activities such as walking, stair-climbing, and sitting may contribute to femoral stent fractures and subsequent clinical sequelae.