Effect of stent-graft compliance on hemodynamics and aortic stiffening in an in vivo porcine study.

Abstract

Compliance mismatch is a key contributor to adverse vascular remodeling and long-term hemodynamic complications following endovascular aortic repair. However, few in vivo studies have systematically compared the biomechanical and hemodynamic impacts of compliant versus conventional stent-grafts. In this study, we evaluated an elastomeric nanofibrillar stent-graft (NF-SG) against a commercially available stiff stent-graft (CS-SG) in a swine model, focusing on the effect of stent-graft type on the hemodynamic indices. Twenty Yucatan minipigs were divided into three groups: Control, CS-SG, and NF-SG. The latter two underwent endovascular implantation of the stent-grafts. Hemodynamic assessments were conducted at baseline, immediately post-implantation, and at 18-week follow-up. Local PWV, pressure, pulsatility, distensibility, and harmonic waveform analyses were performed at the ascending and descending thoracic aorta. CS-SG implantation led to a significant increase in PWV (from 4.72 to 7.66 m/s), marked reductions in aortic pulsatility at the stented site (from 6.4% to 1.7%), as well as suppressed harmonic contribution (from 39.3% to 29.3%) and distortion (from 0.12 to 0.05), indicating impaired distal impedance regulation. In contrast, the NF-SG preserved baseline PWV (4.69 to 5.37 m/s) and maintained physiological waveform profiles, with minimal changes in harmonic contribution and distortion. NF-SG also showed a smaller reduction in pulsatility at the stented site (from 6.1% to 3.1%). These findings demonstrate that NF-SG exhibits superior biomechanical compatibility by preserving aortic compliance and normal hemodynamic function. Compliant stent-grafts may offer a promising strategy to reduce the long-term cardiovascular burden associated with conventional endovascular repairs. Compliance mismatch is a significant challenge in endovascular aortic repair, contributing to adverse remodeling and long-term hemodynamic complications. Despite its clinical importance, few in vivo studies have systematically compared the biomechanical and hemodynamic impacts of compliant versus conventional stent-grafts. To address this gap, we performed a longitudinal study in a porcine model, comparing the performance of an innovative elastomeric nanofibrillar stent-graft with that of a commercially available stiff stent-graft. We demonstrate that implantation of the stiff stent-graft led to significant and sustained increases in pulse wave velocity, reduced aortic pulsatility, and impaired distal impedance regulation. In contrast, our elastomeric stent-graft preserved physiological aortic compliance and hemodynamic function, with minimal disruption to harmonic waveform profiles and distal pulsatility. These findings suggest that compliant stent-grafts may offer a promising strategy to reduce the long-term cardiovascular burden associated with conventional endovascular repairs.