Post-Thrombotic Syndrome

What is Post-Thrombotic Syndrome?

The post-thrombotic syndrome (PTS) is a complication from having had a blood clot known as deep vein thrombosis (DVT). Many people who have had a DVT of the leg or arm recover completely; others may be left with symptoms and physical signs in the affected limb(s) that are collectively known as the post-thrombotic syndrome. Overall, PTS occurs in 20-40 percent of patients after an episode of lower extremity DVT, making it is the most common complication. PTS can still occur even though appropriate anticoagulant treatment for DVT was given.

Why is PTS a problem?
PTS is a frequent side-effect of DVT and, while symptoms can wax and wane over time, it is a chronic, lifelong condition. PTS leads to patient suffering and disability and is costly to society. Severe PTS can cause painful venous ulcers or sores that are difficult to treat and tend to recur. They occur in 5-10 percent of patients.

Why does PTS occur?
When a clot forms in a vein, the valves inside the vein can be damaged by the clot or by the surrounding inflammation. The damaged valves as well as residual clot create an obstacle for blood returning from the leg veins back to the heart, which results in increased venous pressures in the leg.

About the Authors: Nathalie Routhier, MD is Assistant Professor at University of Montreal. Susan R. Kahn,MD is an internist and clinical epidemiologist based at the Jewish General Hospital in Montreal, where she is Director of the Thrombosis Program.