Comparison of the biaxial mechanical characteristics of the above and below-knee human lower extremity arteries

Presenter Information

Pauline StruczewskaFollow

Presenter Type

UNO Graduate Student (Masters)

Major/Field of Study

Biomechanics

Other

Biomechanics

Advisor Information

Dr. Alexey Kamenskiy

Location

MBSC304 - G (Masters)

Presentation Type

Oral Presentation

Start Date

24-3-2023 9:00 AM

End Date

24-3-2023 10:15 AM

Abstract

Peripheral Artery Disease (PAD) often refers to the atherosclerotic obstruction of the main artery in the lower extremities that leads to reduced blood flow and oxygen delivery. It affects over 230 million people worldwide and is associated with significant morbidity and mortality. Over 250,000 endovascular and surgical PAD repairs occur annually, but their clinical outcomes continue to disappoint, often resulting in failed treatments and the need for reintervention. Biomechanical and structural arterial characteristics play important roles in vascular pathophysiology and influence the results of repairs, but their segmental differences along the artery length are insufficiently understood. Recent studies have characterized above-knee superficial femoral and popliteal arteries, but little information is available on the arteries below the knee, which include the anterior tibial, posterior tibial, and peroneal vessels.

The goal of our study was to compare the mechanical and structural characteristics of the above-knee femoropopliteal (FPA: Superficial Femoral [SFA] and Popliteal Arteries [PA]) to the below-knee tibial (Anterior Tibial [AT], Posterior Tibial [PT], and Peroneal [Per]) arteries from the same human subjects. This was done using high-resolution μCT imaging, planar biaxial mechanical testing, constitutive modeling, and bi-directional histological evaluation.

Arteries were procured by LiveOn Nebraska from N = 10 human subjects (average age 51, range 42-61 y.o.) within 24 hours of death after obtaining consent from the next of kin. For each subject, seven segments along the length were tested: [SFA], [PA], [AT arch], [AT], tibioperoneal trunk, [PT], and [Per]. Half of the arteries had vascular disease with medial calcification (average 2.33% by volume, range 0.09%-7.89%). Based on morphometry measurements, a reduction of arterial thickness was observed along the length of the artery from ~1.8mm for the [SFA] to ~1.08 for the [Per]. Inner arterial diameters decreased from ~5.6 for the [SFA] to ~2.04 for the [Per]. Mechanically, the below-knee arteries were stiffer than those above the knee. At 100kPa Cauchy stress, tibial arteries demonstrated stretches of 1.1-1.2, while the femoropopliteal arteries stretched up to 1.35. Above-knee segments demonstrated higher anisotropy than below-knee arteries and were more compliant longitudinally. Below-knee arteries were more isotropic, and some had reversed compliance with a more compliant circumferential direction.

The results of this work contribute to a better understanding of location-specific human lower extremity artery biomechanics and may inform the development of better medical devices for PAD treatment.

Scheduling

9:15-10:30 a.m., 10:45 a.m.-Noon, 1-2:15 p.m.

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Mar 24th, 9:00 AM Mar 24th, 10:15 AM

Comparison of the biaxial mechanical characteristics of the above and below-knee human lower extremity arteries

MBSC304 - G (Masters)

Peripheral Artery Disease (PAD) often refers to the atherosclerotic obstruction of the main artery in the lower extremities that leads to reduced blood flow and oxygen delivery. It affects over 230 million people worldwide and is associated with significant morbidity and mortality. Over 250,000 endovascular and surgical PAD repairs occur annually, but their clinical outcomes continue to disappoint, often resulting in failed treatments and the need for reintervention. Biomechanical and structural arterial characteristics play important roles in vascular pathophysiology and influence the results of repairs, but their segmental differences along the artery length are insufficiently understood. Recent studies have characterized above-knee superficial femoral and popliteal arteries, but little information is available on the arteries below the knee, which include the anterior tibial, posterior tibial, and peroneal vessels.

The goal of our study was to compare the mechanical and structural characteristics of the above-knee femoropopliteal (FPA: Superficial Femoral [SFA] and Popliteal Arteries [PA]) to the below-knee tibial (Anterior Tibial [AT], Posterior Tibial [PT], and Peroneal [Per]) arteries from the same human subjects. This was done using high-resolution μCT imaging, planar biaxial mechanical testing, constitutive modeling, and bi-directional histological evaluation.

Arteries were procured by LiveOn Nebraska from N = 10 human subjects (average age 51, range 42-61 y.o.) within 24 hours of death after obtaining consent from the next of kin. For each subject, seven segments along the length were tested: [SFA], [PA], [AT arch], [AT], tibioperoneal trunk, [PT], and [Per]. Half of the arteries had vascular disease with medial calcification (average 2.33% by volume, range 0.09%-7.89%). Based on morphometry measurements, a reduction of arterial thickness was observed along the length of the artery from ~1.8mm for the [SFA] to ~1.08 for the [Per]. Inner arterial diameters decreased from ~5.6 for the [SFA] to ~2.04 for the [Per]. Mechanically, the below-knee arteries were stiffer than those above the knee. At 100kPa Cauchy stress, tibial arteries demonstrated stretches of 1.1-1.2, while the femoropopliteal arteries stretched up to 1.35. Above-knee segments demonstrated higher anisotropy than below-knee arteries and were more compliant longitudinally. Below-knee arteries were more isotropic, and some had reversed compliance with a more compliant circumferential direction.

The results of this work contribute to a better understanding of location-specific human lower extremity artery biomechanics and may inform the development of better medical devices for PAD treatment.