Microvascular Anastomotic Thrombosis in Experimental Diabetes Mellitus

Abstract

An experimental model was developed to investigate the effects of glycemic control and pentoxifylline administration on microvascular anastomotic patency rates in streptozotocin-induced diabetic rats. Diabetes was confirmed by blood glucose levels of more than 300 mg/dl prior to administering insulin and/or pentoxifylline. Microvascular anastomoses of the femoral artery and vein were performed 4 weeks after induction of diabetes. Subsequently, the comparative rates of anastomotic thrombosis in diabetic and nondiabetic groups with or without insulin or pentoxifylline administration were assessed by direct visualization of the anastomotic sites after 4 days. The results suggest that hyperglycemia impairs the post-operative patency of microvascular venous anastomoses. The diabetic animals maintained under insulin regimens that tightly controlled their serum glucose levels (100 to 200 mg/dl) experienced patency rates similar to those of nondiabetic controls (p < 0.05). Pentoxifylline improved microvenous patency at all levels of hyperglycemia studied, suggesting a possible hemorrheologic mechanism for microvascular venous anastomotic thrombus formation in diabetic animals.

A Random-Pattern Skin-Flap Model in Streptozotocin Diabetic Rats

“…Five rats with blood glucose levels less then 200 mg/dL were excluded from the study (9.25%). Colen et al 13 found this rate as 12% with the same dosage in his study. The application dose of streptozotocin varies between 45 and 100 mg/kg.…”

“…30 Various physical properties of erythrocyte membrane, such as deformability, doublet formation, and viscosity, are altered in poorly controlled diabetes. 13,31,32 Diabetes has procoagulant effects in many different ways, which result in microthrombus formation in microcirculation. 23,33,34 Different types of microvascular and microcirculatory damage is present [35][36][37] (eg, induced hyperviscosity and hypercoagulability, 13,33,[38][39][40] increased oxidative damage, 21,41 damage of vital enzymes and proteins by nonenzymatic glycosylation).…”

“…Babovic et al 12 examined the flaps' tolerance to ischemia in streptozotocin-induced diabetic rats and found that flaps' survival decreased significantly to 40% in the 3-week diabetic group's animals. In 1997, Colen et al 13 investigated microvascular anastomotic thrombosis in experimental diabetic rats and found that hyperglycemia impairs microvascular venous anastomoses' postoperative patency in the fourth week after diabetes' induction. But none of these studies has answered the 4 questions cited below.…”

Risk Factors of Anastomotic Thrombosis in 200 Head and Neck Free Flaps among Asian Patients

“…Several experimental studies have suggested an association between noncontrolled hyperglycemia and vessel thrombosis [12]. We believe that perioperative management of hyperglycemia is crucial; otherwise, the incidence of anastomotic thrombosis could be higher, as observed in experimental models.…”

Incidence and significance of microscopic pathological lesions found in pedicle and recipient vessels used in microsurgical breast reconstruction

“…3 Early experiments on microvascular anastomoses in diabetics showed defective intimal healing across the arterial anastomotic site, 4 with hyaline degeneration and aneurysm caused by thickening of the basement membrane; 5 yet few studies have examined the structural alterations that occur in microvenous anastomoses in diabetics. 6 Smoking causes fibrosis of the intima of blood vessels, thereby reducing free-flap success. 7 However, simple translation of these experimental results into clinical situations may be inappropriate.…”