Hemorheological, morphological, and oxidative changes during ischemia‐reperfusion of latissimus dorsi muscle flaps in a canine model

Abstract

Although ischemia-reperfusion (I/R) strongly influences muscle flap survival in reconstructive surgery, there is limited knowledge about its relation to hemorheological parameters and oxidative stress markers in flaps. In the present study we investigated these changes during I/R of latissimus dorsi muscle (LDM) flaps in beagle dogs. In four animals LDM flaps were prepared bilaterally. The right side served as control, while the left side's vascular pedicle was clamped for 60 minutes, and a 60-minute reperfusion was allowed afterward. Blood samples (0.5 ml each) were taken from the pedicle's vein bilaterally before and after the ischemia, and at the 5th, 15th, 30th, 45th, and 60th minutes of the reperfusion, for hematological and erythrocyte aggregation tests. In muscle biopsies, taken before and after I/R, histological investigations and tests for measuring gluthation-peroxidase (GSH-PX) activity, glutathione (GSH) and carbonyl concentrations, and thiobarbituric acid reactive substances (TBARS) content were carried out. In I/R side leukocyte count increased during the reperfusion with a peak at the 30th minute. Hematocrit continuously increased from the 15th minute. In the first 5 minutes of the reperfusion, erythrocyte aggregation increased, than tented to be normalized. In muscle homogenates GSH-PX activity did not change markedly, GSH content slightly decreased, carbonyl and TBARS content increased during reperfusion. A 1-hour ischemia and reperfusion of LDM flaps caused local changes of leukocyte distribution and erythrocyte aggregation, supposedly due to the metabolic and inflammatory reactions. Oxidative damage during reperfusion was also demonstrated.

Autonomization of epigastric flaps in rats

“…The Hb level and blood flow have been already discussed in the literature, as the hemoglobin concentration has become an accepted predictive variable of flap outcome 17–21. The blood flow predicted for thromboembolism was found to be a predictor of flap loss due to surgical complications and a high re‐exploration rate 5, 6, 22.…”

Intra and postoperative evaluations of microcirculation and micro-rheological parameters in a rat model of musculocutaneous flap ischemia-reperfusion

“…In our previous study, 1-hour ischemia-reperfusion of a latissimus dorsi muscle flap in the canine resulted in local changes of white blood cells' distribution and increased red blood cell aggregation, and attributed the cause to the induction of local metabolic inflammatory reactions in the first 60 minutes of reperfusion 32 . Furthermore, in various other I/R experimental models (kidney, testicle, small intestine) the red blood cell deformability deteriorated during the ischemic event as well as on the 1 st and 3 rd postoperative days 33 .…”

Is the knowledge on tissue microcirculation important for microsurgeon?

“…These factors have to be considered specifically in patients with diabetes, hypertension, obesity, and peripheral vascular disease where rheological factors, in combination with ischemiareperfusion-induced generation of free oxygen radicals, release of NO and pH-dependent changes in vessel diameter, may directly influence the outcome of free tissue transfers. 105,106 …”