[General principles of oxygen transport in the venous wall]

To review the mechanisms of oxygen transport in the walls of arteries and veins and to consider whether oxygen transport might limit oxygen consumption in the venous wall.

(i) To review evidence for the contributions of transport from the vascular lumen and transport from the vasa vasorum to the supply of oxygen to the walls of arteries. (ii) To use the general principles of oxygen diffusion through tissues to extrapolate the findings of investigations of oxygen transport into arterial walls to transport into the walls of the larger veins.

The magnitude of oxygen transport from the vessel lumen into the vessel wall is dependent on the partial pressure of oxygen (PO2) in the vessel lumen. While luminal PO2 is constant and high in arteries, it is a physiological variable in veins of healthy people. In larger veins, there is evidence that flow in the vasa vasorum increases as PO2 in the vessel lumen falls. The extent to which this regulatory action of the vasa vasorum may be comprised by raised venous pressure and venous distension has not been defined.