Perioperative Transcranial Doppler Changes in Subclavian Artery Occlusive Disorders

Transcranial Doppler sonography (TCD) for investigation of the vertebro-basilar (VB) system was performed in one patient with left subclavian artery (LSCA) occlusion and the other with LSCA stenosis before and after axial artery to axial artery bypass. Preoperative Doppler waveforms of the left vertebral artery (VA) of the patient with LSCA stenosis showed transient reversal, whereas the patient with LSCA occlusion showed complete reversal. Increased blood flow in the right VA, suggested by an increased flow velocity, apparently compensated for flow in the left VA. TCD done shortly after the operation revealed that the direction of flow in the left VA was still transiently reversed in both cases. Flow reversal continued to be mild and limited to the end-diastolic or presystolic periods in the patient with LSCA stenosis, whereas the patient with LSCA occlusion showed gradually progressive reversal with the last waveforms being completely reversed.