The effect of carotid artery stenting on capillary transit time heterogeneity in patients with carotid artery stenosis

Abstract

Stenting led to significant increase in cerebral blood flow (<i>p</i> < 0.001), and decrease in cerebral blood volume (<i>p</i> = 0.001) and mean transit time (<i>p</i> < 0.001); this was accompanied by reduction in oxygen extraction fraction (<i>p</i> < 0.001) and capillary transit-time heterogeneity (<i>p</i> < 0.001), but an overall increase in relative capillary transit-time heterogeneity (RTH: CTH divided by MTT; <i>p</i> = 0.008). No significant change was observed with respect to cerebral metabolic rate of oxygen. The median volume of tissue with MTT > 2s decreased from 24 ml to 12 ml (<i>p</i> = 0.009), with CTH > 2s from 29 ml to 19 ml (<i>p</i> = 0.041), and with RTH < 0.9 from 61 ml to 39 ml (<i>p</i> = 0.037) following stenting. These changes were correlated with the baseline degree of stenosis.<b>Discussion:</b> Stenting improved the moderate stage of haemodynamic compromise at baseline in our cohort. The decreased relative transit-time heterogeneity, which increases following stenting, is probably a reflection of decreased functional capillary density secondary to chronic hypoperfusion induced by the proximal stenosis.<b>Conclusion:</b> Carotid artery stenting, is not only important for prophylaxis of future vascular events, but also is critical for restoration of microvascular function in the cerebral tissue.