Jh. Barker et al., EXPERIMENTAL-STUDY OF THE RELATIONSHIP BETWEEN ALTERATIONS IN TISSUE PERFUSION AND ANASTOMOTIC PATENCY, Microsurgery, 14(6), 1993, pp. 409-415
It is generally believed that alterations in perfusion which endanger
a free flap or replant are directly related to thrombus formation and
obstruction of blood flow at the anastomotic site. Recent experimental
work in our laboratory suggests that the presence of platelet emboli
downstream in the microcirculation might be responsible at least in pa
rt for postoperative perturbations in perfusion. To determine whether
changes in tissue perfusion can occur in the absence of corresponding
changes in anastomotic, patency we studied microvascular blood flow in
the exposed rat cremaster flap model. We made continuous measurements
of both anastomotic patency and downstream microcirculatory perfusion
following small vessel repair. Using this approach we found that duri
ng one hour after clamp release and reperfusion in the 10 animals stud
ied, pedicle artery blood pressure, which indicates pedicle patency in
this model, was functionally normal 97% +/- 2 of the time while blood
flow in the downstream tissue (cremaster) remained normal an average
of only 65% +/- 7 of the time. In most cases these flow alterations we
re associated with the presence of visible platelet emboli in the micr
ocirculation. From these studies we conclude that when flap perfusion
failure temporarily occurs, a microsurgeon must consider not only the
anastomosis but also the downstream microcirculation when searching fo
r a possible cause. (C) 1993 Wiley-Liss, Inc.