Reversal of the direction of internal carotid artery blood flow by occlusion of the common and external carotid arteries in a swine model

In a swine model, blood flow direction [antegrade (+) and retrograde (-)] and velocity were defined within the common (CCA), internal (ICA), and external (ECA) carotid arteries during CCA occlusion with and without ECA occlusion and blood aspiration. In seven anesthetized swine, Doppler recordings of blood flow direction and velocity were performed in the CCA, ICA, and ECA, before and after vessel(s) occlusion, and after passively and actively induced reversal of blood flow direction. Baseline ICA and ECA blood flow direction and velocities were 92 +/- 4 and 90 +/- 3 cm/sec; and, with CCA occlusion, the ICA velocity decreased to 30 +/- 2 cm/sec (P < 0.001). No flow (zero velocity) occurred with CCA and ECA occlusion. An artificial femoral arteriovenous fistula's continuous gradient passively reversed ICA blood flow direction (-), with the recorded blood's velocity (-24 +/- 4 cm/sec) increasing with continuous active aspiration to -90 +/- 6 cm/sec. Occlusion of the CCA occlusion alone was unable completely to halt ICA antegrade blood flow direction, while CCA and ECA occlusion completely stopped ICA antegrade flow. CCA and ECA occlusion, when coupled with an arteriovenous fistula arteriovenous and/or aspiration, resulted in ICA blood flow direction reversal, whose velocity could be actively augmented. (C) 2003 Wiley-Liss, Inc.