The effect of pedicle artery vasospasm on microhemodynamics in anatomically perfused and extended skin flap tissue

The aim of this study was to evaluate quantitatively the influence of pedic le artery vasospasm on the microcirculation in skin flaps, particularly in the jeopardized extended portions. For this purpose, the hamster island ski n flap model was used, which allowed for simultaneous assessment of hemodyn amics in both the pedicle artery and the microvasculature of the flap by in travital microscopy, Vasospasm was induced by applying a V3 microvascular c lamp for 30 seconds, Clamping resulted in a severe vasospasm, with the arte ry exhibiting a diameter of 7% +/- 2% (mean +/- standard error) of its orig inal diameter (n = 10; p < 0.01), and with a reduction of total blood flow to the flap of 11% +/- 2% (p < 0.01). Diameter and blood flow recovered gra dually to baseline levels after 25 and 15 minutes respectively. During reco very from severe pedicle artery vasospasm (moderate to mild vasospasm), the arterioles in the anatomically perfused nap tissue (n = 38) showed reactiv e vasodilation (p < 0.01), which was absent in the extended tissue (N = 49; p < 0.01 vs, anatomic). At a pedicle artery vasospasm of 50% of the origin al diameter, blood flow was restored to normal levels in the anatomically p erfused arterioles, but remained below baseline in the extended part (partl y p < 0.05 vs. baseline and anatomic). The findings suggest that the develo pment of ischemic necrosis in extended flap portions may be promoted by pro longed, moderate vasospasm, which is well tolerated in the anatomically per fused tissue because of its high capacity for implementing compensatory loc al regulatory mechanisms.