OBJECTIVES: To investigate the impact of thoracic endovascular aortic repair (TEVAR) on longitudinal strain and assess aortic tensile properties in order to better understand complications associated with TEVAR. METHODS: Twenty fresh thoracic porcine aortas were harvested and connected to a mock circulatory loop driven by a centrifugal flow pump at body temperature. Length measurements were conducted before and after TEVAR through aortic marking, high-definition imaging and custom-developed software under physiological pressure conditions (i.e. between 100 and 180 mmHg with 20 mmHg increments). Longitudinal strain was derived from length amplitude divided by the baseline length at 100 mmHg. Three groups of stent-graft oversizing were created (0–9, 10–19 and 20–29%). Finally, elastic properties of the aortic samples were assessed in both longitudinal and circumferential directions through uniaxial tensile testing. Longitudinal strain was compared before and after TEVAR, and stress-to-rupture was compared among specimens and locations. RESULTS: TEVAR induced a longitudinal strain decrease from 11.9 to 5.6% (P