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Figure 1 (A) This 5.3-kg infant with hypoplastic left heart syndrome s/p Norwood I operation underwent a pre-Glenn catheterization. Hand injection of contrast demonstrated complete occlusion of the left iliofemoral venous system, with contrast entering the paravertebral venous collateral circulation. (B) Careful evaluation of the early phase of the same injection demonstrated a tiny superficial femoral vein remnant (arrow) before filling by the superimposed paravertebral venous collaterals. (C) The same injection on the lateral projection showed the anterior position of the femoral vein remnant (arrow) compared to the posterior paravertebral collateral veins.