3:36 PM Abstract No. 86 Predictors of iliocaval in-stent restenosis

Abstract

Chronic venous disease (CVD) occurs in 1-5% of adults. Iliocaval obstructive lesions play a significant role in the development of CVD. Iliocaval stenting is a mainstay treatment for CVD. However, in-stent restenosis (ISR) occurs in 5-23% and is related to recurrence of symptoms and possible decreased patency. We sought to evaluate risk factors associated with ISR. Patients who underwent successful iliocaval stenting were compiled from a departmental database of all lower extremity venous stents from 1996-2018. In total, 760 iliocaval stents were placed in 160 patients (47.5% female, 52.5% male), mean age 48.7 years. Median follow-up was 332 days (range, 0-5627 days). ISR was defined as >50% reduction in luminal diameter. Risk factors examined for ISR included age, gender, type of stent (Wallstent, Boston Scientific, Natick MA) vs. SMART stent (Cordis, Santa Clara, CA), diameter and length of stent, and diameter of angioplasty balloon. Veins included were the inferior vena cava (IVC), bilateral common iliac veins (CIV), and bilateral external iliac veins (EIV). Median and mean time to ISR was 177 and 422 days respectively (range, 11-3985 days). Neither age nor gender were significantly associated with ISR. Location of stent was not associated with increased risk of ISR. ISR occurred in 15.1% of IVC stents, 15.2% of CIV stents, and 18.4% of EIV stents. In both the CIV and EIV, Wallstents had a decreased risk of restenosis when compared to SMART stents (CIV: HR -3.0, P <0.005; EIV: HR -2.4, P = 0.02). Stent brand was not a risk factor for IVC ISR. Angioplasty balloon diameter following stent deployment was a significant risk factor for ISR as increased balloon diameter was associated with a decreased risk of IVC ISR (HR -2.7, P = 0.01). Balloon diameter did not affect ISR for CIV or EIV stents. Our study had clinically acceptable and similar rates of ISR for the IVC, CIV and EIV. Wallstents may decrease ISR in iliac veins but are similar to SMART stents when placed in the IVC. Some literature suggests that over dilation of stents may help long-term patency (4); however, we found that use of larger balloons decrease ISR in IVC stents only.