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Isolated Support with an Extracorporeal Perfusion System Deters Ischemia-related Metabolic Derangement of a Rat Fasciocutaneous Free Flap
Fuat Baris Bengur, MD; Ryan A. Orizondo, PhD; Chiaki Komatsu, MD; Kelly R. Strong; Mario G. Solari, MD
University of Pittsburgh
2022-01-15
Presenter: Fuat Baris Bengur, MD
Affidavit:
I certify that the material proposed for presentation in this abstract has not been published in any scientific journal or previously presented at a major meeting.
Director Name: Mario Solari
Author Category: Fellow Plastic Surgery
Presentation Category: Basic Science Research
Abstract Category: General Reconstruction
Background
Machine perfusion of vascularized tissues can prevent the ischemic duration between harvest and transfer for autologous or allogeneic tissues. Temporary ex vivo perfusion maintains viability of free flaps until they are fully supported by neovascularization from the wound bed. This study aimed to establish a rodent free flap model of machine perfusion and determine the potential of the developed protocol to deter ischemia-related metabolic derangement.
Methods
Epigastric fasciocutaneous free flaps were harvested and transferred to a closed circuit that provides circulatory and respiratory support. Whole rat blood was recirculated for 8-hours, while maintaining arterial-like perfusion pressures. Blood samples were drawn during support. Extracellular tissue lactate and glucose levels were characterized with a custom microdialysis probe placed in the flap tissue. Lactate to glucose ratio (L/G) was used as an indicator of tissue metabolism and compared with warm ischemic, cold ischemic and anastomosed free flap controls.
Results
Maintenance of physiologic arterial pressures (85-100 mmHg) resulted in stable flow rates (350-450 uL/min). Blood-based measurements showed maintained glucose and oxygen consumption throughout support, indicating sustained metabolic activity. Average normalized L/G for the perfused flaps was 5- to 32-fold lower than that for the warm ischemic flap controls (p<0.05).
Conclusion
We developed a rat model of extended machine perfusion of a fasciocutaneous free flap. Ex vivo perfusion maintained the tissue metabolic activity out to 8 hours of support. This affordable model can also be used in the future to assess critical elements of support in this setting and explore novel therapies.
