Ex-vivo Mechanical Augmentation of Human Saphenous Vein Graft By UV-A Irradiation in Emergency Vascular Reconstruction – Preliminary Results

Abstract

Abstract Introduction In vascular reconstruction in arterial trauma, ruptured abdominal aortic aneurysm or ruptured aneurysmal arteriovenous fistula, the challenge no longer lies in the surgical procedure itself, but rather the prevention of intimal hyperplasia, thrombosis and aneurysm formation, in parallel with extending as long as possible the patency of the grafts. The aim of this study is to present the preliminary findings of a novel non-ionizing radiation-based therapeutic method for stabilizing and strengthening the extracellular matrix of the venous wall, improving the biomechanical profile of the autologous graft used in myocardial and lower limb revascularization. Material and methods We developed the protocol and method for UV-A irradiation as a new method of mechanical augmentation of the resistance structure of the venous graft. Samples of the superficial femoral artery, superficial femoral vein, and great saphenous vein (GSV) were extracted from a 58-year-old patient who underwent above-the-knee amputation, and were prepared in 5 × 5 cm2 patches. Additionally, we analyzed the samples biomechanically biaxially with the BioTester® 5000, in which we established a 25% equibiaxial stretch. The GSV sample was also treated by UV-A irradiation after being kept in riboflavin 5′-phosphate monosodium salt for 30 min. Results After UV-A treatment of the GSV wall, we observed an important increase of Cauchy stress from 82 kPa to 131 kPa in the longitudinal axis and from 66 kPa to 115 kPa in the circumferential axis. Young’s modulus also changed after treating the GSV wall from 0.564 MPa to 1.218 MPa (longitudinal) and from 0.397 MPa to 0.709 MPa (circumferential). As a result of the therapy, we observed a considerable similarity of the mechanical behavior of the GSV wall to that of the artery wall. Conclusion The photocrosslinking of collagen fibbers at the vein graft adventitia hardens and stiffens the venous wall, making it behave like the arterial wall after treatment. These preliminary ex vivo results on human vascular tissue may serve as the foundation for the development of new treatment approaches utilizing mechanical augmentation of the vein grafts.