Definition of the Post-thrombotic Syndrome, Differences Between Existing Classifications

All clinical definitions of PTS were highly associated with the reference standard of ambulatory venous pressure, with higher AVPs observed in the more severely affected groups. The ability of the scoring systems to discriminate between DVT and control legs as well as the observed prevalence of PTS differed substantially. In part this is due to the considerable overlap in AVP in the different clinical groups, reflecting the fact that our reference standard has substantial deficiencies. No clear advantage was found in any one system of classification over the rest.