To assess the frequency and anatomic distribution of the segmental aplasia of the great saphenous vein (GSV) using ultrasonography in patients who presented with a clinical etiologic anatomic and pathophysiologic (CEAP) score 1 and above.

A prospective study on 670 limbs of 335 consecutive patients evaluated for segmental aplasia of the GSV with ultrasonography. The difference of segmental aplasia of the GSV between patients with and without GSV insufficiency was searched.

Segmental aplasia of the GSV was found in 223 of 670 limbs (33%). Segmental aplasia of the GSV was seen in 65 of 189 limbs (34.4%) with GSV insufficiency and 45 of 146 limbs (30.8%) with normal GSV on the right side (P = 0.52), and 65 of 194 limbs (33.5%) with GSV insufficiency and 44 of 141 limbs (31.2%) with normal GSV on the left side (P = 0.72).

Segmental aplasia of the GSV was seen in one-third of patients who had a CEAP score 1 and above. The frequency of the segmental aplasia was almost the same in the right and the left limbs and was similar in patients with or without GSV insufficiency.