RESUMO
The presence of femoral vein (FV) duplicity has potential influence in the misdiagnosis of deep vein thrombosis. Also, FVs are suitable vascular substitutes, especially in the substitution of infected prosthetic grafts. The objective of this study was to describe the prevalence, anatomic patterns and characteristics of FV duplicity in adult individuals by duplex scan examination. A total of 174 adult individuals were submitted to duplex-scan examinations of both lower limbs. Individuals with duplex signs of present or previous DVT or with poor quality duplex images were excluded from the investigation. The remaining group consisted of 157 individuals (94 females), with a total of 314 limbs studied. Along with the conventional duplex investigation sequence, the FV was scanned both in transversal and longitudinal views. The number, extension and diameter of FVs were documented. It was found that 173 limbs (55.1%) had duplicated FV. Duplicity in the whole femoral extension was noted in 82 (26.1%) limbs, and out of these only 28 (8.9% of the overall number) had accessory veins with a diameter approximate to (at least 75%) the main FV. Partial (distal or proximal) duplications were seen in 89 (28.3%) limbs. A third FV was present in 28 limbs. As a possible vascular substitute, 99.0% of the main FVs and 25.4% of the accessory veins presented diameters superior to 6 mm, a suitable value for iliac substitution. In conclusion, FV duplicity is frequent, and occurred in 55% of all limbs studied. However, complete extension duplicated veins with similar diameters was an uncommon condition, noticed in fewer than 10% of limbs.