ABSTRACT
The circulation system seems to have early encounters with pathophysiologic processes
during ischemia and reperfusion, such as overproduction of oxygen radicals, nitric
oxide depletion, and leukocyte plugging. The aim of this study was to determine the
superficial perfusion and vessel distribution of the epigastric flap with a laser
Doppler Imaging (LDI) system during ischemia/reperfusion, and to observe the clinical
outcomes 7 days after reperfusion in a separate set of animals. An epigastric flap
from male Sprague-Dawley rats (320 to 380 g) was used to assess perfusion in sham
animals (n=6) or in 12 hr-ischemia animals (12 hr of ischemia and 3 hr of reperfusion,
n = 10) with the LDI system. In a separate experiment, flap size, flap failure index,
and histologic sections of the flap from sham animals (n=6) and 12-hr ischemia animals
(n=6) were evaluated 7 days after reperfusion. Evaluation of the vessel distribution
demonstrated a diffuse picture of flap perfusion after clamp release. Moreover, in
the distal portion of the flap, circulation stopped immediately, resulting in a significantly
decreased perfusion in the 12-hr ischemia animals during reperfusion, when compared
with pre-surgical values (100 percent) or sham animals (77 ± 26.5 vs. 108 ± 9.6 percent
PU). On day 7, the flaps of animals after ischemia and reperfusion showed significant
shrinkage, an increase in flap failure index, as well as necrosis, edema, and leukocyte
infiltration. Based on the findings, the authors propose that, after prolonged ischemia,
the circulation becomes diffuse, and ``no-reflow'' occurs in the distal portions of
the myocutaneous flap during reperfusion. Perfused areas, assessed with the LDI early
during reperfusion, might still become necrotic after several days. In the authors'
flap model, edema formation and leukocyte infiltration seem to be related more to
ischemia reperfusion damage than to thrombus formation.
KEYWORD
Epigastric flap - circulatory changes - prolonged ischemia
