Vasomotion does inhibit mass exchange between axisymmetric blood vessels and tissue

Vasomotion, the name given to the physiological phenomenon whereby blood vessel walls exhibit rhythmic oscillations in diameter, is a complex process and very poorly understood. It has been proposed as a mechanism for protecting tissue when perfusion levels are reduced, since it has experimentally been shown to occur more frequently under such conditions. However, no quantitative evidence yet exists for whether the oscillation of the wall actually has any effect on mass transport to tissue. In our previous work, it was shown that the presence of non-linearities in the governing equation could result in a significant change in time-averaged mass transport to tissue: however, it was not possible, due to the limitations of the model, to determine whether time-averaged mass transport increased or decreased. This model is extended in this paper through coupling of the one-dimensional axisymmetric mass transport equations in tissue and blood to quantify the effects of vasomotion on mass transport to tissue. The results show that over a wide parameter range, surrounding those values calculated from experimental data, vasomotion does inhibit mass transport to tissue in a one-dimensional axisymmetric blood vessel by an amount that is predominantly dependent upon the amplitude of oscillation and that increases rapidly at larger oscillation amplitudes.