Systematic Review Evaluates Incidence, Outcomes, and Management of Venous Stent Migration

Key Findings

• Between 1994 and 2020, 31 articles (29 case reports, two case series) were identified, providing data for 54 venous stent migration events.
• In most reported cases, stents were ≤ 60 mm long, and stents were > 14 mm in diameter in only three reports; none of the articles reported migration of stents > 100 mm long.
• The iliocaval segment had the highest incidence of migration, followed by the central and renal veins.
• Retrieval was attempted in 85.5% of cases (65.2% endovascular, 34.8% open), with 100% of attempts having a satisfactory outcome.

ENDOVASCULAR TODAY ASKS…

We asked study coauthors Stephen Black, MD, FRCS; Gerry O’Sullivan, MD; and Kush Desai, MD, about the results and their implications:

Stent migration is a potentially catastrophic complication of venous stenting, and you note that training efforts are encouraged. What are three hallmarks that should be emphasized during training to reduce this risk?

1. Patient selection: This is of paramount importance, particularly with nonthrombotic iliac vein lesions (NIVLs). We know that clinically silent iliac vein compression is present in a significant portion of the population, and obviously no stent is needed in these cases. Many patients are currently referred with “left iliac vein compression” based on cross-sectional studies with no symptoms whatsoever. Equally, however, stents are being placed for dubious indications such as “ankle swelling,” which is not likely to improve with stent placement. Clear identification of those NIVL patients likely to benefit from stent placement is key, including patients with venous claudication, significant edema that extends into the thigh, venous stasis ulceration that does not completely respond to superficial vein therapy, and chronic pelvic pain in selected females. The workup must include the elimination of alternative explanations for symptoms.

2. Use proper intraprocedural imaging techniques: Use venography and intravascular ultrasound (IVUS) in a complementary manner. Identify venographic findings that suggest hemodynamically significant lesions (eg, collaterals, internal iliac vein reflux). Use IVUS to demonstrate that the compression is fixed through the respiratory cycle and with Valsalva maneuvers, as well as to select the stent size and length.

3. Proper stent size selection (both diameter and length): IVUS is critical here. Size the stent off a normal reference segment; in most NIVL cases, this should be the external iliac vein. In our experience, most patients should get a 14- or 16-mm-diameter stent. Do not select stent size off of prestenotic dilation in the common iliac vein—this may lead to gross oversizing. Selection of stent length can be aided by marker catheters on IVUS; the stent should extend caudally well into the normal external iliac vein so that it is well anchored. We typically do not place stents shorter than 120 mm in length.

In the authors’ experience of nearly 2,000 stent implantations, we have not seen a single case of stent migration following the procedure. In experienced hands, this potentially devastating complication should be extremely rare.

The article concludes that robust venous registries are needed to further evaluate factors related to stent migration. What might this registry landscape look like (eg, industry-run postmarket registry, society registries, government/other large real-world databases), and what would the ideal follow-up means, frequency, and duration include?

The current data suffer from underreporting; it is likely that more migrations have occurred than have been currently reported. Vigilance is now mandatory given that on-label devices for iliofemoral venous obstruction have only recently come to market in the United States, where the majority of NIVL treatment occurs. To that end, postmarket studies, such as an FDA 522 postmarket surveillance study, are a good first step in capturing clinical activity and events in the treatment of iliofemoral obstruction, with mandated short- and medium-term imaging and clinical follow-up. This would include abstraction of intraprocedural data (including venography and IVUS) and follow-up data (duplex ultrasound and clinical metrics) to determine outcomes and adverse event rates. However, it is imperative that all parties–governing bodies such as the FDA, industry, and users—commit to proper postmarket data collection.