Optimal ultrasound criteria for defining the severity of vertebral artery in-stent restenosis.

The aim of the study described here was to establish ultrasound criteria for defining the severity of vertebral artery in-stent restenosis. A total of 197 patients with vertebral artery stents were enrolled in this study. Color Doppler ultrasonography was performed after stenting. Peak systolic velocity and end-diastolic velocity within the stent (PSV(stent), EDV(stent)) and at the intervertebral segments were recorded. The ratio of the PSV at the origin to that at the intervertebral segment was calculated. With digital subtraction angiography as the reference standard, the optimal cutoff values of hemodynamic parameters identifying 50%-69% and 70%-99% restenosis were determined by receiver operating characteristic analysis. The optimal cutoff values of hemodynamic parameters identifying 50%-69% restenosis were PSV(stent) ≥ 170 cm/s, EDV(stent) ≥45 cm/s and PSV ratio ≥2.7, and those for 70%-99% restenosis were PSV(stent) ≥220 cm/s, EDV(stent) ≥55 cm/s and PSV ratio ≥4.2. In conclusion, color Doppler ultrasonography is a reliable method for monitoring patients with avertebral artery stents.