Lack of symmetry in the major lower limb veins.

Background: Contemporary texts frequently present the venous system of the lower limb as a prime example of bilateral symmetry. However, overt bilateral asymmetry may be noted. This study was designed to examine and to quantify the level of symmetry in the lower extremity veins.
Methods: This prospective cohort study evaluated major anatomic differences between right and left lower extremity veins in adult patients. Two hundred patients presenting with signs and symptoms of chronic venous disease (CVD; class 2-6) and venous reflux on duplex ultrasound were examined. A second group of 25 healthy volunteers without reflux or obstruction were used as controls. Those with conditions that could potentially alter vasculature, including vascular malformation, lower extremity trauma, and previously documented surgery for venous disease or bypass operations, were excluded. Only overt changes in the main superficial veins (great saphenous and small saphenous veins) and deep veins (femoral, popliteal, peroneal, and tibial veins) of the lower extremities were examined for symmetry. The level of small saphenous vein termination and thigh extension veins were also included. Location and extent of hypoplasia or aplasia and venous duplication or triplication were noted for all venous segments.
Results: Of the 100 patients (200 limbs) with CVD class 2-3 (age, 49 years; range, 21-78 years), the extent of asymmetry in the superficial system, deep system, and combined was 84%, 86%, and 100%, respectively. Similarly, of the 100 patients (200 limbs) with CVD class 4-6 (age, 56 years; range, 28-84 years), the level of asymmetry in the superficial system, deep system, and combined was 83%, 84%, and 100%, respectively. Fifty (100 limbs) healthy volunteers (age, 46 years; range, 18-74 years) also presented similarly elevated levels of asymmetry compared with both cohorts of differing CVD class severity (superficial, 78%; deep, 84%; both, 100%). The most common reason for asymmetry in the great saphenous vein was hypoplasia or aplasia, whereas duplication was rare. In the small saphenous vein, the level of termination, thigh extension, and hypoplasia were the more frequent reasons. In the deep veins, duplication of the femoral and popliteal veins at different locations and extents was the most common finding for asymmetry. These findings remained consistent for all subgroups of patients and healthy controls.
Conclusions: A complete lack of symmetry is consistently seen in CVD patients and healthy subjects. Asymmetry in the veins of the lower extremities appears to be the norm. This is true despite examination of only overt changes and exclusion of multiple veins from the comparison.
(Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)