Morphological, hemodynamical and hemorheological changes of mature artificial saphenous arterio‐venous shunts in the rat model

Abstract

Artificial femoral arterio-venous (AV) shunts are widely used in rodent models for studying shunt maturation and to optimize various surgical techniques. However, little is known about complex circulatory, microcirculatory, and hemorheological effects of end-to-side saphenous AV shunts. We aimed to study these parameters in mature AV shunts. Studying these questions in CD rats, end-to-side anastomoses were made between the left saphenous artery and vein. On the right-side the nonoperated saphenous vessels served as own control. Furthermore healthy control animals were also investigated. On the 8th to 12th postoperative week microcirculatory and blood flow measurements were performed and blood samples were taken both from the shunt's arterial and venous limbs and from the nonoperated side vessels. Hematological parameters, erythrocyte aggregation, and deformability were determined. The entire shunt and the control vessels were removed for histological examinations. The skin microcirculation on shunt side slightly increased on thigh and decreased on paws versus the nonoperated side. Blood flow measurements made directly on the vessels showed that arterial to venous blood flow rate ratio was 1.59 ± 0.29 on nonoperated side and 1.2 ± 0.13 on the shunt side, and 1.49 ± 0.05 in control animals. Erythrocyte aggregation and deformability worsened on the shunt side. Histologically increased number of smooth muscle elements and connective tissue were found in venous limb of the shunts. The artificial AV shunt between the saphenous artery and vein seems to be a suitable model for further functional-morphological and hemorheological examinations of hemodialysis in various states and diseases.

Carotid-Jugular Fistula Model to Study Systemic Effects and Fistula-Related Microcirculatory Changes

“…Mortality rates in fistula studies have generally ranged between 0 and 47% [16, 22-24]. Most of the deaths occur 24–48 h after surgery, because of congestive heart failure (CHF) or for unknown reasons [16, 22, 25]. No postoperative deaths and no infections were observed in the current study.…”

A modified microsurgical model for end-to-side selective portacaval shunt in the rat: intraoperative microcirculatory investigations

“…Concerning the follow-up of morphological and functional changes of artificial shunts, in a previous work we demonstrated significant hemodynamic and notable microrheological (red blood cell deformability and aggregation) alterations in case of artificial sapheno-saphenous arterio-venous shunt model in the rat 44 . In a recent study, we found aorto-portacaval differences in the certain hemorheological parameters (red blood cell aggregation, erythrocyte elongation index, osmotic gradient ektacytometry parameters) 45 .…”

Aorto-porto-caval micro-rheological differences of red blood cells in laboratory rats: Further deformability and ektacytometrial osmoscan data

“…The majority of data referring to arterio-venous or porto-caval micro-rheological differences are originated from experimental studies, which deal with ischemia-reperfusion of limbs [15,26,30], small intestine [7], liver [10], cerebral hypo-and hyperperfusion [18,25] and artificial arterio-venous shunt models [14]. However, there is a lack of targeted comparative hemorheological analysis for exploring these arterio-venous or porto-caval micro-rheological relations.…”

“…7,10,14,15,18,19,25,26]. The small volume of required blood sample for these laboratory tests (microliter-amount) and the sophisticated methodology provided the opportunity for further investigation of arterio-venosus micro-rheological differences in laboratory animals [13,14,29], or as laboratory standardization concerns, the systemic venous versus capillary blood samples in human [28]. The standardization of blood sampling methods and sites are important for the experimental surgical and microsurgical research models, too.…”