Intermittent subclavian venous obstruction: utility of venous pressure gradients.

A 22-year-old-man with intermittent obstruction of the subclavian vein at the thoracic outlet was evaluated by a pullback venous pressure gradient measurement and phlebography. The use of venous pressure gradient measurement allowed precise definition of the site of venous obstruction in the thoracic outlet and guided appropriate surgical therapy. The gradient information is of potential importance as many normal individuals have positional phlebographic venous compression at the thoracic outlet. Early identification of subclavian compression syndromes may avoid venous thrombosis with its attendant morbidity.