Long-term improvement of limb reflux prevalence and severity after iliac vein stent placement.

Background: The effect of iliac vein stenting on ipsilateral limb reflux is unknown and has remained a matter of speculation. It has been suggested that the propensity for reflux might worsen when proximal stenosis is corrected. This could allow for retrograde flow with coughing and the Valsalva maneuver, stressing the valve. We examined this hypothesis by an analysis of the long-term effects of iliac vein stenting on limb reflux using a single-center, retrospective analysis of prospectively collected data.

Methods: Reflux data from duplex ultrasound of 1387 limbs in 1228 patients who had undergone iliac vein stenting from 1997 to 2018 were analyzed. Of the 1387 limbs, 632 (46%) had had ipsilateral duplex ultrasound-determined valve reflux before stenting, and 747 limbs (54%) had not had reflux; data were missing for 8 limbs. Reflux status before and after stenting was available for seven individual segments for each limb in the database for analysis (total, 9653 segments). The stented patients were examined for reflux at least annually during the follow-up period (range, 1-26 years). Segmental reflux prevalence was detected using duplex ultrasound. We have referred to this as "duplex reflux" or simply "reflux." Reflux severity was graded using (1) a reflux segmental score, assigning one point each for refluxing segments in the limb; (2) air plethysmography (venous filling index [VFI]); and (3) ambulatory venous pressure (venous filling time [VFT]).

Results: Prestent duplex reflux was present in a combination of superficial, deep, and perforator segments. Reflux prevalence ranged from 7% of deep femoral segments to 51% at the popliteal segment. Post-stent reflux resolution varied from 21% at the femoral vein segment to 58% at the perforator segments. Reflux had completely resolved in 23% of the limbs. New-onset reflux was rare, with a median incidence of 7% for all segments at risk, with cumulative improvement (Kaplan-Meier curve) in reflux severity (segment score, VFI, and VFT) for most limbs. These metrics were unimproved, with residual reflux in only 18%, 11%, and 6% (segment score, VFI, and VFT, respectively) of the limbs at long-term follow-up.

Conclusions: Long-term follow-up of limbs after iliac vein stenting has shown that the associated ipsilateral reflux prevalence and severity will improve in most limbs over time.