Impact of vascular structure on in-sent restenosis after vertebral artery stenting / 中国脑血管病杂志

ABSTRACT

Objective To investigate the influencing factors of in-stent restenosis (ISR) following stenting for vertebral artery ostium stenosis (VAOS). Methods From January 2013 to December 2014, a total of 325 patients receiving stenting for severe vertebral artery stenosis (≥70%).which was diagnosed with color Doppler ultrasonography (CDUS) and confirmed by digital subtraction angiography (DSA) were retrospectively recruited. All patients were divided into the ISR group (116 cases) and the non-ISR group (209 cases). CDUS was utilized for periodical follow-up after the procedure. All vascular structure characteristics and related clinical information of the target vertebral artery were recorded. The Kaplan-Meier was used to calculate the accumulative ISR incidence and generate the survival curves. The Log-rank test (χ2 test or Fisher exact test) was used to compare the discrepancy in survival curves. Cox proportional risk regression model was used to analyze the possible influencing factors. Results (1) All patients were followed up for a median of 14 (6, 38) months. There was no significant difference between the two groups in age, gender, side of severe stenosis, diabetes mellitus, hypertension, smoking history, symptoms of posterior circulation and posterior circulation cerebral infarction (all P>0.05). (2) There was significant difference in stent type using of drug eluting stent (DES) or bare metal stent (BMS) between the two groups(48/68 vs. 125/84 , χ2 =10. 18, P = 0. 001). The stent diameter in the ISR group was significantly larger than that in the non-ISR group ([4. 5 ±0. 7]mm vs. [4. 3 ±0. 8]mm, t = -2. 52, P =0. 010). There was no significant difference in stent length between the two groups (P > 0. 05). (3) Compared with the non-ISR group, the ISR group had more prevalent tortuosity of vertebral artery (42. 2% [49/116] us. 26. 8% [56/209] , χ2 = 8.14) and larger original diameter of the vertebral artery before stenting ([3.5 ± 0. 6]mm vs. [3. 3 ± 0. 5]mm, t = - 2. 74). The differences were significantly (P 0. 05). (4) Further analyzed by Cox step-wise regression, DES (HR, 0. 58, 95 % CI 0. 39 -0. 86, P = 0. 01) and tortuosity of the target vertebral artery (HR, 1. 52, 95% CI 1. 02 -2. 28, P =0. 04) were influencing factors for ISR after VAOS stenting. While the ratio of postoperative diameter to preoperative original diameter was not significantly correlated with the occurrence of ISR (P >0. 05). (5) Kaplan-Meier survival curve analysis was performed on the cumulative incidence of ISR in patients with vascular tortuosity. There was no statistically significant difference in the cumulative incidence of ISR in patients with vertebral artery tortuosity using BMS (Log-rank χ2 = 1. 72, P = 0. 19), but DES (Log-rank χ2 = 8. 62, P = 0. 003). Conclusion DES could effectively reduce the incidence of ISR. Tortuosity of the target vertebral artery was a risk factor for ISR after stent implantation, especially when using DES.