Monday’s plenary revealed the results of a landmark National Institutes of Health-sponsored trial that gives guidance on how to best treat deep vein thrombosis (DVT) patients.
The Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-directed Thrombolysis Trial, known as the ATTRACT Trial, found that some patients who underwent pharmacomechanical catheter-directed thrombolysis (PCDT) were less likely to develop moderate to severe post-thrombotic syndrome (PTS) and had less swelling and pain in the first 30 days of treatment than patients who only received anticoagulants. However, Suresh Vedantham, MD, FSIR, national principal investigator for the ATTRACT Trial, said the data showed that PCDT did not prevent the development of PTS.
“Post-thrombotic syndrome was approximately the same in both treatment groups,” said Dr. Vedantham, SIR president-elect, during his presentation. “There was no difference in the primary outcome; in fact, the point estimates were fairly shockingly similar. When we looked at severity of post-thrombotic syndrome, however, we saw that the proportion of patients with moderate to severe post-thrombotic syndrome was approximately 25 percent lower in the patients who received thrombalytic therapy.”
ATTRACT is the first national multicenter, randomized trial to compare the ability of two treatment strategies — PCDT and standard treatment — to reduce the incidence and severity of DVT.
PCDT delivers a clot-busting drug directly into the blood clot through a specially designed catheter. This minimally invasive procedure is designed to rapidly eliminate the clot, reduce pain and swelling and improve the leg’s circulation.
The trial found that most patients with DVT, a dangerous blood clot that forms in a deep leg vein, should continue to be treated with anticoagulant drugs alone, without undergoing a procedure-based intervention. The trial suggests that patients with larger blood clots, known as iliofemoral DVT, are most likely to benefit from the procedure since they are most likely to develop PTS. However, Dr. Vedantham did note that there was no statistical difference between iliofemoral and femoral popliteal groups.
“There’s enough in there about the iliofemoral population that looks good that I would probably continue to offer [PCDT] to those patients, and I wouldn’t consider somebody who didn’t have iliofemoral DVT,” said Timothy P. Murphy, MD, FSIR, medical director of the Vascular Disease Research Center at Brown University, one of several panelists following Dr. Vedantham’s presentation that put ATTRACT into perspective.
Dr. Vedantham and his colleagues developed the ATTRACT Trial following an SIR Foundation research consensus panel on DVT in 2004. The trial was submitted to the National Heart, Lung, and Blood Institute in 2008 and received $10.2 million in funding.
Researchers randomized a cohort of 692 patients with blood clots above the knee to receive either standard treatment for DVT (consisting of anticoagulants and the use of elastic compression stockings) or PCDT in addition to the standard treatment.
Following patients for 2 years, researchers assessed patients’ quality of life and PTS development. Researchers found that DVT patients who received both blood-thinning drugs and PCDT were 25 percent less likely (18 percent with PCDT vs. 24 percent without) to develop moderate to severe PTS. However, PCDT did not prevent PTS.
Dr. Vedantham said treating DVT patients has long been a controversial topic among physicians. When blood thinners are used, 40 percent of DVT patients still develop PTS. Patients who develop this condition experience pain and swelling in their legs, affecting their ability to perform simple tasks such as walking.
Dr. Vedantham believes this new research will be the impetus for improving patient care and outcomes. Physicians can eliminate costly and invasive therapy for patients when unnecessary and better educate patients about their disease, he said. Susan Kahn, MD, director of the Thrombosis Program at Jewish General Hospital, echoed his sentiment.
“I think the ATTRACT study provides extremely valuable, contemporary data on the actual frequency of PTS,” Dr. Kahn said.
Researchers will continue to study DVT treatments and endovascular treatments to reduce the severity of PTS and to treat established PTS.