May-Thurner syndrome stenting: how often the stent stays open, from every published study

In May-Thurner syndrome the right iliac artery presses the left iliac vein against the spine. The usual treatment is a stent, a metal mesh tube that holds the vein open; when a clot has already formed, it is removed first. Each hospital publishes its own results. We read the abstracts of every iliac vein compression treatment study in PubMed and put the numbers side by side, so you can see what to expect across many hospitals, not just one.

Iliac vein stenting, step by step (4 steps)

1. Access through a vein. The doctor punctures a vein in the leg, using ultrasound to guide the needle. Studies describe access in the groin or thigh, or behind the knee. A thin tube (sheath) is placed in the vein so tools can be passed up to the narrowing. Source: study 1, study 2.

2. Imaging the narrowing. X-ray pictures with contrast dye (venography) and a tiny ultrasound probe inside the vein (intravascular ultrasound, IVUS) show where and how much the vein is narrowed. In one large study, IVUS detected over 90% of these narrowings, venography 66%. Source: study 1, study 2.

3. Balloon and stent. A balloon widens the narrowed segment, and a self-expanding stent, a tube of woven nitinol wire, is left in place to hold the vein open under the artery. In one study of 40 patients, the open area at the squeeze grew from about 35 to 130 square millimeters. Source: study 1, study 2, study 3, study 4.

4. After the procedure. Doctors may prescribe blood thinners after stenting; in one study, patients took them for 3 months. There is no agreed best regimen yet. Ultrasound checks follow to see that the stent stays open; one center scanned within 2 weeks, then every 3 months for the first year. Source: study 1, study 2, study 3.

Prefer a video? Watch the 90-second captioned video explainer.

Results by type of problem

"Stent open (weighted)" counts every patient once, so large studies count more. It is primary patency: the stent stayed open without another procedure, at the longest time point each study reported. "Median study" is the middle value when studies are lined up from lowest to highest.

The groups differ in patients and in how long they were followed, so the table is not a head-to-head comparison. "Mixed patient groups" are studies that report people with and without a previous clot together.

All studies

Filter by type of problem. Each title opens the study in PubMed. "Stent open" is primary patency with the time point in months; "Improved" is the share of patients whose symptoms got better, as that study defined it. The stent model is shown under the title when the abstract names it.

Treatment AllType of lesion not statedStent, no clot (non-thrombotic compression)Without stentClot removal + stent (acute DVT)Mixed patient groupsStent for old clot damage (post-thrombotic) only studies with a success rate

Extracted by our editors from the PubMed abstracts of 498 May-Thurner / iliac vein compression papers screened (201 report treatment outcomes), built November 8, 2026. Every number was checked against a verbatim quote from the abstract.

How we built this

• We searched PubMed for May-Thurner syndrome, iliac vein compression, non-thrombotic iliac vein lesions and iliac vein stenting, and screened every paper with an abstract that mentions treatment and is not a single case report.
• For each study we recorded the number of treated patients, the type of problem (no clot, recent clot, old clot damage), the treatment, follow-up, primary and secondary patency, symptom improvement, ulcer healing, technical success, complications and repeat procedures, only as stated in the abstract.
• Every number is stored with the exact sentence from the abstract that supports it, and a script checks that the sentence and the number are really there. A few studies were excluded or corrected by our editors (for example, studies where vein compression was not the condition treated); each decision is documented.
• When an abstract gave only "patency" without saying which kind, we counted it as primary patency.
• Systematic reviews are listed in PubMed but not added to the totals, to avoid counting the same patients twice.

Limitations

• Abstracts are short; full papers may contain details we did not capture.
• Studies check the stent at different times, from a few months to ten years, and stents tend to close more often over time.
• Some studies include patients whose vein was narrowed by something other than May-Thurner compression.
• Hospitals with good results are more likely to publish, so real-world results may be lower.
• Some groups published several papers about overlapping patients.
• A narrowed iliac vein on a scan is common in people without symptoms. These results apply to patients whose symptoms were judged to come from the compression.

Questions to ask before stenting

• How sure are you that the compression, and not another problem, is causing my symptoms? Was intravascular ultrasound (IVUS) used to measure it?
• Is there a clot now, or damage from an old clot? How does that change my chances?
• Which stent would you use, and how many venous stents does your team place each year?
• How long will I take blood thinners after the stent, and which ones?
• How will the stent be checked, and what happens if it narrows?

Read our guide to May-Thurner syndrome, and about pelvic congestion syndrome and nutcracker syndrome, other vein compression problems.

MALS Compass is an independent educational website, not a medical provider, and is not affiliated with any hospital, clinic or university. This page is educational information and does not replace advice from your own doctor. For any question about your health, please contact your doctor or an official healthcare institution.