Incidence of in-stent restenosis and hemodynamics after vertebral artery stenting

Objective To analyze the hemodynamic characteristics of vertebral artery ostium stenosis (VAOS) stenting during the periprocedural period and the incidence of in-stent restenosis (ISR) by color Doppler ultrasonography (CDUS). Methods A total of 420 patients who underwent VAOS stenting at neurosurgery department, vascularsurgery department, and interventional therapy department, Xuanwu Hospital from January 2013 to December 2014 were enrolled consecutively into the present retrospective cohort study. CDUS was used to conduct regular follow-ups for the patients. T-tests were used to analyze the difference of hemodynamic parameters and survival analysis was applied to calculate the cumulative incidence of restenosis at different time points within 2 years after stenting. Results The preoperative peak systolic velocity in ostium segment (PSVos) was (307±103) cm/s, which significantly decreased to (109±31) cm/s after the procedure (P <0.01). The end diastolic velocity in ostium segment (EDVos) decreased from (97±44) cm/s before surgery to (31±8) cm/s after the procedure (P<0.01). A total of 330 patients underwent a median period of 12(4,15) months of follow-up (range: 2-24). ISR occurred in a total of 120 (36.4%) patients, of whom 102 developed ISR within 1 year after stenting. When ISR occurred, the diameter of the vertebral artery decreased from (2.9±0.5) mm to (1.6±0.6) mm (P<0.01), the PSVos increased from (110±26) cm/s to (224±79) cm/s (P<0.01), and the EDVos increased from (31±8) cm/s to (68±29) cm/s (P<0.01). The velocity of distal intervertebral PSVis was decreased as well [(65±22) cm/s vs (70±19) cm/s, P<0.01]. Conclusion VAOS stenting is associated with a relatively high incidence of ISR, most of which occur 1 year after VAOS stenting. CDUS, as an effective and non-invasive imaging modality, could evaluate the periprocedural hemodynamic characteristic and should be widely used in the therapeutic and follow-up evaluations after VAOS stenting. Key words: Ultrasonography, Doppler, color; Vertebral artery; Stent; Restenosis