Abstract
Background Mechanical evacuation of capillary thrombi in free flaps is difficult, and often
requires thrombolytic therapy. Utilizing machine perfusion systems, the possibility
rises to salvage free flaps ex vivo by administering high doses of thrombolytic agents.
The primary aim of this pilot study in a porcine model is to investigate the feasibility
of ex vivo thrombolysis using an extracorporeal perfusion machine.
Methods A model of stasis-induced thrombosis was used in 12 free rectus abdominis flaps harvested
from six Dutch Landrace pigs. Compromised flaps were ex vivo perfused with University
of Wisconsin preservation solution and treated according to the following study groups:
(1) 1 mg of tissue plasminogen activator (t-PA) as additive, (2) 3 mg of t-PA as an
additive, and (3) no thrombolytic additive. Microcirculation was assessed using near-infrared
fluorescence angiography.
Results Pedicled abdominal flaps were created and thrombus formation was successfully induced.
Eleven abdominal flaps were perfused using the modified heart-lung machine setup.
Near-infrared fluorescence angiography showed delayed or no filling was noted in the
control group. In comparison, the flaps which were perfused with 1 mg t-PA or 3 mg
t-PA as additive showed increased fluorescence intensity curves.
Conclusion This pilot study in a porcine model presents a reliable and reproductive stasis-induced
thrombosis model in free flaps. By adding t-PA to a custom-made extracorporeal perfusion
system, the indocyanine green fluorescence intensity curves increased of all flaps
that were perfused with different dosages of t-PA as additives, indicating restoration
of capillary pressure and microcirculatory inflow.
Keywords
swine - therapeutic thrombolysis - perfusion
