Arteriovenous Fistula Theory

The concept of increased venous flow in the dermal venous plexus was expanded upon by Pratt who reported that increased venous flow in patients with CVI could be clinically observed.32 He attributed the development of venous ulceration to the presence of arteriovenous connections and coined the term arterial varices. He reported that in a series of 272 patients with varicose veins who underwent vein ligation, 24% had arteriovenous connections. Of the 61 patients who developed recurrences, 50% occurred in patients with arteriovenous communications identified clinically by the presence of arterial pulsations in venous conduits. Pratt hypothesized that increased venous flow shunted nutrient and oxygen rich blood away from the dermal plexus leading to areas of ischemia and hypoxia and resulting in venous ulceration. Pratt's clinical observations however, have never been confirmed with objective scientific evidence. Experiments with radioactively labeled microspheres have never demonstrated shunting and have therefore cast serious doubts on the validity of this theory.

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