Experimental model for the study of retrograde flow

Abstract

BackgroundVenous arterialization has been adopted as a strategy for salvage of limbs in critical ischemia without the distal arterial bed, with successful outcomes, but the mechanisms by which irrigation of the extremities takes place are still unknown.ObjectivesTo develop an experimental model to test hypotheses that could explain the mechanisms of blood supply in venous arterialization.MethodsEleven pigs underwent a period of hind limb ischemia followed by reperfusion achieved by venous arterialization, after interposition of conduits filled with 10 ml (5 animals – group 1) or 1 ml (6 animals – group 2) of China Ink. After euthanasia, the limbs were amputated and underwent histological analysis.ResultsUnder optical microscopy, ink staining was observed in the arteriolar lumen of six (55%) of the eleven pigs used in the experiment; four (80%) out of five from group 1 and two (33%) out of six from group 2.ConclusionsThe experimental model was capable of testing the hypothesis. The presence of China Ink in the arteriolar lumen shows that it is possible to supply the arterial vessels by means of venous arterialization.

Estudo comparativo experimental da distribuição do fluxo arterial, em isquemia e reperfusão por circulação retrógrada, através de mapeamento dúplex

“…[1][2][3][4][5][6][7][8][9] The underlying concept is based on the theory that if primary arterial blood pressure is absent or greatly reduced in the arterioles, then blood supplied via the arterialized distal venous system will be able to supply peripheral tissues with sufficient oxygenation. [3][4][5]10 Studies have attempted to compare, using physical and laboratory variables, the degree of ischemia and reperfusion produced by arterialization of veins in animal models. 11 This study compared the distribution of arterial vascular flow in limbs in which physiological circulation was maintained against the flow in contralateral limbs subjected to arterialization of veins, by studying hemodynamic variables and Doppler indices in the vascular beds.…”

Isquemia e reperfusão por circulação retrógrada: estudo comparativo experimental

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] The concept is based on the theory that in the absence of primary arterial blood pressure in arterioles, blood supplied by arterialization of the distal venous system is capable of supplying the peripheral tissues and providing adequate oxygenation. [3][4][5]13 Many different variables have been used to evaluate tissue hypoxia in animal models, such as assessment of arterial flow using Doppler ultrasound (US), 14,15 temperature measurements, 16 blood gas analysis, 17 lactate 18 and creatine phosphokinase (CP) assays, 19 and measurements of arterial blood pressure at extremities. 20 The objective of this study is to compare the behavior of these clinical and laboratory variables in pigs' hind limbs after induction of ischemia, with and without reperfusion via retrograde circulation, against each other and in relation to a control group.…”