Study Demonstrates Inadequacy of the Term “Proximal DVT”

January 7, 2016—An analysis of 1,338 patients with acute lower limb deep venous thrombosis (DVT) supports the hypothesis of the inadequacy of the term “proximal DVT,” according to a study published by Prof. Marianne G.R. De Maeseneer, MD, et al online ahead of print in the European Journal of Vascular and Endovascular Surgery (EJVES).

According to the investigators, for decades acute lower limb DVT has been subdivided into distal DVT (isolated to the calf veins) and proximal DVT (extending above the calf vein level). The aim of this study was to analyze the anatomic site and extent of thrombus in a large cohort of patients with acute DVT.

As summarized in EJVES, the investigators performed a retrospective analysis of all patients aged 18 years or older, presenting with unilateral DVT according to duplex ultrasound investigation at the University Hospital of Antwerp, Belgium (1994–2012). The anatomic site and extent of thrombus was registered and subdivided into five segments: calf veins (segment 1), popliteal vein (segment 2), femoral vein (segment 3), common femoral vein (segment 4), and iliac veins with or without inferior vena cava (segment 5).

The median age of the 1,338 patients (50% male) included was 62 years (range, 18–98 years). Left-sided DVT was predominant (57%). DVT was limited to one segment in 443 patients, of whom 370 had DVT isolated to the calf veins (28% of total cohort). 

In 968 patients with what was previously called proximal DVT, the median number of affected segments was three (range, 1–5 segments). In this group, iliofemoral DVT (at least involving segment 4 and/or 5) was present in 506 patients (38% of total cohort), whereas the remaining patients had femoropopliteal DVT (at least in segment 2 and/or 3 but not in segments 4 or 5). Iliofemoral DVT without thrombus in segments 1 and 2 was present in 160 patients (12% of total cohort).

The investigators concluded that this study illustrates the large diversity of thrombus distribution in patients previously described as having proximal DVT and, therefore, this term should be abandoned and replaced with iliofemoral and femoropopliteal DVT. Patients with iliofemoral DVT (38%) could be considered for early clot removal; 12% of all patients with DVT would be ideal candidates for such intervention, advised the investigators in EJVES.