Deep venous thrombosis and superficial venous reflux

Objective: Although superficial venous reflux is an important determinant o f post thrombotic skin changes, the origin of this reflux is unknown. The p urpose of this study was to evaluate the frequency and etiologic mechanisms of superficial venous reflux after acute deep venous thrombosis (DVT). Methods: Patients with a documented acute lower extremity DVT were asked to return for serial venous duplex ultrasound examinations at 1 day, 1 week, 1 month, every 3 months for the first year, and every year thereafter. Refl ux in the greater saphenous vein (GSV) and lesser saphenous vein (LSV) was assessed by standing distal pneumatic cuff deflation. Results: Sixty-six patients with a DVT in 69 lower extremities were followe d up for a mean of 48 (SD +/- 32) months. Initial thrombosis of the GSV was noted in 15 limbs (21.7%). At 8 years, the cumulative incidence of GSV ref lux was 77.1% (SE +/- 0.11) in DVT limbs with GSV involvement, 28.9% (+/- 0 .09%) in DVT limbs without GSV thrombosis, and 14.8% (+/- 0.05) in uninvolv ed contralateral limbs (P < .0001). For LSV reflux, the cumulative incidenc e in DVT limbs was 23.1% (+/- 0.06%) in comparison with 10% (+/- 0.06%) in uninvolved limbs (P = .06), In comparison with uninvolved contralateral lim bs, the relative risk of GSV reflux for DVT limbs with and without GSV thro mbosis was 8.7 (P < .001) and 1.4 (P = .5), respectively. The relative risk of LSV reflux in thrombosed extremities compared with uninvolved extremiti es was 3.2 (P = .07). Despite these observations, the fraction of observed GSV reflux that could be attributable to superficial thrombosis was only 49 %. Conclusions: Superficial venous thrombosis frequently accompanies DVT and i s associated with development of superficial reflux in most limbs. However, a substantial proportion of observed reflux is not directly associated wit h thrombosis and develops at a rate equivalent to that in uninvolved limbs.