Postoperative evaluation of in situ saphenous vein bypass with technetium-labelled albumin microspheres.

Technetium-labelled serum albumin microspheres have been used to study arteriovenous shunting in in situ saphenous vein bypasses. Their diameter (15 micron) enables the microspheres to be trapped at the capillary level, either in the limb or in the lungs, according to the extent of arteriovenous shunts. The observed shunting ranged from practically nothing to 90%. The worst distal activity counts as well as the worst scintigraphic aspects (giving a qualitative view of the nutritional circulation of the limb) were found in patients with poor intraoperative arteriographic evaluation of run-off. Persisting clinical inconvenience due to fistulas was only found in patients with over 60% shunting. No patients, even those with up to 90% shunting, had any evidence of ischemia. Arteriovenous shunting would thus seem well tolerated to a certain extent, and the ligation of major arteriovenous fistulas is to be recommended.