24-hour Perfusion of Porcine Myocutaneous Flaps Mitigates Reperfusion Injury: A 7-day Follow-up Study

Abstract

Background: Static cold storage is the gold standard of preservation in vascularized composite allotransplantation and allows a preservation time of 4–6 hours. Machine preservation is a promising technique for prolonged preservation; however, studies on extended preservation that compare different preservatives are scarce. This study aims to assess the feasibility of 24-hour acellular perfusion and compares different preservation solutions in a porcine myocutaneous flap replantation model. Methods: Six harvested bilateral myocutaneous flaps of three Dutch Landrace pigs were perfused hypothermically for 24 hours with University of Wisconsin machine perfusion solution (UW-MPS; n = 2) or histidine-tryptophan-ketoglutarate solution (HTK; n = 2) or preserved on ice for 4 hours (n = 2) before orthotopic replantation. Animals were observed for 7 days after replantation. Skeletal muscle injury was assessed by biochemical markers during perfusion, and muscle biopsies were analyzed for ischemia reperfusion injury directly after preservation and at 1, 3, and 7 days after replantation. Results: Markers of muscle damage varied during perfusion, but decreased overall in both perfusion groups. Flap weight increased 60% and 97% in the HTK-perfused flaps, compared with -6% and -7% in the UW-MPS-perfused flaps after 24 hours. Histopathologic evaluation demonstrated decreased muscle damage in flaps perfused with HTK compared with the UW-MPS-perfused flaps at 1 week after replantation. Conclusions: Machine perfusion of myocutaneous flaps for 24 hours with subsequent replantation is feasible, but warrants further research. Perfusion with HTK solution seemed to result in better histological outcomes 7 days after reperfusion compared with UW-MPS.

VCA supercooling in a swine partial hindlimb model

“…Kruit et al and later our team described the first machine perfusion protocols applied to large animal VCA 27 , 28 , 36 , 39 , 44 – 46 . Nonetheless, current dynamic hypothermic and SNMP techniques are limited to preservation periods of 24 to 36 h due to factors such as edema and vascular resistance 34 , 47 – 49 . Supercooling has proven itself a promising technique to overcome these limits and go beyond several days in liver 22 , 50 .…”

Supercooling: a promising technique for prolonged preservation in solid organ transplantation, and early perspectives in vascularized composite allografts

“…So far, a few teams only used HMP, SNMP, and NMP techniques. Kruit et al have shown pioneering work with up to 36 h preservation of musculocutaneous VCA in a pig model using HMP ( 26 , 110 ). Pig hindlimbs were also successfully preserved for 24 h using SNMP before transplantation, as shown in our preliminary study ( 111 ).…”

Review of machine perfusion studies in vascularized composite allotransplant preservation

“…For flap models, Brouwers et al ( 64 ) perfused swine rectus abdominis myocutaneous flaps for 24 h at 10°C and reported a weight decrease in UW perfused flaps (−6% and −7%), whereas HTK perfused flaps had a 97% and a 60% increase in weight. After replantation and follow-up, both groups showed degenerative changes in muscle histology ( Table 2 ).…”