The Effects of Stiff Stent-Grafts on Segmental Aortic Stiffness and Left Ventricular Mass: A Pilot Swine Model Study
Year: 2019
Type: article
Abstract: Mentor: Jason MacTaggart Program: General Surgery Introduction: Endovascular stent-grafting is a first-line therapy for many aortic pathologies, but stent-grafts are constructed using non-compliant materials that stiffen a segment of the aorta. This diminishes the Windkessel function, reducing the ability to dampen peak systolic pressures and provide aortic wall recoil, and may lead to left ventricular (LV) hypertrophy. We tested this hypothesis in a swine model. Methods: CTA imaging was performed to assess aortic geometry, and a commercially available stent-graft was implanted into the thoracic descending aorta of a juvenile swine. Pressure waveforms were obtained in the aorta, coronary, carotid, and renal arteries before and after stent-graft placement. After 8 weeks, CTA and pressure measurements were repeated, and the heart and aorta were histologically and mechanically evaluated. An age-matched swine was used as a control. Results: After stent-graft placement, the pulse wave velocity increased 2.5-fold, and pressure waveforms changed their shape. At 8 weeks, the stent-graft animal mean arterial pressure increased 25 mmHg, aortic wall recoil reduced 1.2–2.0-fold proximal to the stent-graft, and was eliminated within the stent-grafted segment. The aorta remodeled to a larger diameter, and became stiffer than control, proximal to and behind the stent-graft. LV mass increased 48% in the stent-graft animal, but only 28% in the control. Cardiac and aortic histology demonstrated signs of fibrosis, increased cellularity, and increased MMP activity in the stent-graft animal. Conclusions: Stiff aortic stent-grafts reduce the Windkessel effect, which may lead to higher pressures, altered pressure waveforms, an inflammatory response, stiffening of the ascending aorta, and LV hypertrophy, which warrants further investigation.
Authors: Aylward, Paul, Kamenskiy, Alexey, MacTaggart, Jason
Institution: University of Nebraska Medical Center
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W2995997015