Improvement in venous-phase delay after superficial temporal artery to middle cerebral artery bypass.

The utility of superficial temporal artery to middle cerebral artery (STA-MCA) bypass before therapeutic internal carotid artery (ICA) occlusion is unclear. A 65-year-old woman with a symptomatic giant left paraclinoid ICA aneurysm underwent endovascular ICA occlusion following STA-MCA double bypass. Preoperative balloon test occlusion (BTO) demonstrated a venous-phase delay of 1.5 s. Only focal improvement in the venous-phase delay was observed immediately after treatment, but three-week postoperative angiography showed remarkable improvement of 0.5 s. To our knowledge, this is the first known case that demonstrates the effect of STA-MCA bypass on postoperative improvement in venous-phase delay.