Rutherford's 067: Biologic Grafts скачать в хорошем качестве

Rutherford's 067: Biologic Grafts

#BiologicGrafts #Allografts #Xenografts #VascularSurgery #BypassGrafts #CryopreservedGrafts #ModifiedGrafts #Patency #LimbSalvage #DialysisAccess #InfectedGrafts #TissueEngineering Drawing on Rutherford's Vascular Surgery, this deep dive covers biologic grafts, non-autogenous vessels used when a patient's own aren't suitable for bypass or access. Sourced from the same species (allografts) or different species (xenografts), they have a long history but early fresh grafts had issues like intimal thickening and immune reaction. Cryopreservation became common for storage, preserving mechanical properties but causing cellular damage and triggering immune responses despite cryoprotectants. Managing this response with ABO matching or immunosuppression proved difficult with mixed results and complications. Patient sensitization is a concern with some types. Structurally modified grafts like bovine carotid artery (BCA) and bovine mesenteric vein (BMV) were developed for durability and reduced immune trigger; human umbilical vein (HUV) grafts were also used but discontinued. Clinical uses include extremity bypass when native vein is unavailable, hemodialysis access, and replacing infected prosthetic grafts. Outcomes vary. Cryopreserved saphenous vein (CSV) for leg bypass shows low patency (~30% at 1 year) but acceptable limb salvage (~71% at 2 years). Aneurysm is a risk in patent CSVs. Cryopreserved femoral vein (CFV) for dialysis access is secondary due to pseudoaneurysms and infection concerns. Cryopreserved aortic allografts are vital for infected aortas, a high-risk surgery, showing reasonable durability. BCA and BMV are used for access with mixed results vs synthetics, but poor for leg bypass. Biologic grafts are essential tools in specific scenarios, but their limitations (variable patency, degeneration, infection, immune response, cost) prevent them from being the ideal solution. Future research focuses on vascular tissue engineering to create better grafts.