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Thrombus distribution varies widely among patients with proximal DVT
Thrombus distribution among patients with proximal deep vein thrombosis is highly diverse, researchers reported in a recent retrospective analysis.
According to Marianne G.R. De Maeseneer, MD, PhD, and colleagues, this diversity is so great that the term “proximal” deep vein thrombosis (DVT) should be discarded in favor of further subdivision into “iliofemoral” and “femoropopliteal” DVT, as this would allow different guideline-based treatment of the two types.
De Maeseneer, from the department of dermatology at Erasmus Medical Centre, Rotterdam, the Netherlands, and colleagues evaluated data on 1,338 adult patients who presented with unilateral, lower-limb DVT at a single facility in Belgium between 1994 and 2012. The cohort was 50% male and the median age was 62 years. The location and extent of thrombus was identified in each patient, and the population was divided according to involvement of the calf veins, popliteal vein, femoral vein, common femoral vein and/or iliac veins with or without inferior vena cava.
Most patients (57%) had left-sided DVT. DVT limited to a single segment occurred in 443 patients and was isolated to the calf veins in 370 patients. DVT involving two segments was present in 208 patients, whereas 345 patients had DVT involving three segments, 149 involving four segments and 193 involving all five segments.
The majority of patients (n = 968) had proximal DVT, with a median of three affected segments per patient. Subanalysis of 945 evaluable patients indicated iliofemoral DVT in 506 cases and femoropopliteal DVT in 439 cases. Femoropopliteal DVT involving the calf, popliteal and femoral veins was the most prevalent type and observed in 267 patients, or 20% of the total population. Among those with iliofemoral DVT, 189 cases did not involve the calf vein and 160 did not have thrombus in either the calf or popliteal veins.
The researchers noted that DVT was isolated to calf veins much more frequently than any other evaluated veins, and that the calf was the likely starting point for thrombus in 65% of the population.
“Patients with an acute lower limb DVT should have a thorough mapping of the thrombus localization by [duplex ultrasound] rather than a simple subdivision into ‘distal’ and ‘proximal’ DVT,” the researchers wrote. “The results of detailed mapping illustrated the large diversity of thrombus distribution in patients previously described as having a ‘proximal DVT.’” They concluded that the term “proximal” DVT should be abandoned in favor of subclassification into “iliofemoral” DVT and “femoropopliteal” DVT, allowing “a more precise description of involved segments ... with potential differentiation of treatment.” – by Adam Taliercio
Disclosure: The researchers report no relevant financial disclosures.