The vertebral arterial (VA) pulsed Doppler waveform can indicate the presence of stenosis of the proximal subclavian artery. Systolic dimple sign (SDS), characterized by a sharp decline in velocity at mid systole, is observed when antegrade flow in the VA is preserved. Once subclavian steal occurs, SDS is no longer evident and retrograde flow appears during at systole. Here we report a 65-year-old man suffering from numbness in the left arm and dizziness during left arm activity, in whom serial monitoring of VA flow was performed during percutaneous transluminal angioplasty (PTA). The blood pressure difference between the two upper extremities was 45mmHg, and SDS was documented on pulsed wave Doppler examination. CTA revealed 80% stenosis with calcification in the left subclavian artery. After obtaining informed consent, the left VA flow pattern was monitored (1)before and (2)after predilatation, (3)stenting, and (4)after dilatation of the proximal subclavian artery. The lesion was successfully dilated by balloon angioplasty with stenting. The VA flow pattern gradually normalized as the PTA procedure progressed, showing (1)SDS, (2)normal but slow acceleration time, (3)increased systolic velocity, and (4)normal with rapid acceleration time. VA flow pattern monitoring during PTA is useful for evaluation of hemodynamics in real time.
