TORONTO (April 13, 2026)—The results of a prominent, National Institutes of Health (NIH) sponsored study into the treatment of post-thrombotic syndrome (PTS) following deep vein thrombosis (DVT) offers hope to patients suffering from this debilitating illness, according to new research presented today at the Society of Interventional Radiology's (SIR) 2026 Annual Scientific Meeting and published in the New England Journal of Medicine .
The study, known as Chronic Venous Thrombosis: Relief with Adjunctive Catheter-Directed Therapy (C-TRACT), compared two treatment strategies for PTS in a randomized, multicenter trial. This is the first public presentation of the long-awaited results of the C-TRACT Trial, which received its primary support from NIH and additional support from SIR Foundation. The trial was co-led by Washington University School of Medicine in St. Louis and McMaster University in Hamilton, Canada.
C-TRACT enrolled 225 patients with moderate to severe PTS at 29 institutions and was led by researchers from multiple specialties, including interventional radiology. Patients were randomly assigned to one of two treatment groups—the active treatment group which received blood-thinning drugs, compression treatment (such as stockings), along with placement of stents in blocked veins that drain blood from the leg by physicians who were mostly interventional radiologists, and a control group that received blood-thinning drugs and compression treatment without stenting.
The trial found that patients in the stent treatment arm showed significantly greater improvement in their PTS severity than the control arm patients, and that this resulted in major improvement in their self-reported quality of life through 6 months. Whereas 93% patients started out with their PTS classified as "severe" by Venous Clinical Severity Score (VCSS), at 6 months only 40% of patients in the stent treatment arm had severe disease, a remarkable shift given that severe PTS has been considered exceedingly difficult to treat.
"Many patients with PTS suffer in silence because few physicians are aware of this complication or know how to effectively treat it. This study suggests that even severe PTS is, in fact, a treatable condition in many patients," said Suresh Vedantham, M.D., FSIR, an interventional radiology physician and professor of radiology at WashU Medicine Mallinckrodt Institute of Radiology, the study's principal investigator.
Every year, about 600,000 Americans experience a deep vein thrombosis, the formation of clots in several different veins that move blood from various parts of the body back to the heart and lungs. Approximately 40% of DVT patients will develop PTS, a long-term complication that causes chronic pain, swelling, fatigue and, in severe cases, venous ulcers, in the affected limb. PTS occurs when blood flow is blocked or flows backward due to damaged blood vessels. Stenting helps restore blood flow in the affected limb by expanding the channel for blood flow in the damaged vessel.
"Standard treatments such as anticoagulation and compression are important but for many patients, such treatments are not enough to improve leg symptoms and enable patients to function normally in their daily lives," said Vedantham, also a professor of surgery at WashU Medicine. "C-TRACT shows that patients with moderate-to-severe PTS and large vein blockage could benefit greatly from endovascular stent treatment, so patients should consult with an interventional radiologist for proper evaluation and management."
