MODIFICATIONS OF PLASMA-LEVELS OF TISSUE FACTOR PATHWAY INHIBITOR ANDENDOTHELIN-1 INDUCED BY A REVERSE TRENDELENBURG POSITION - INFLUENCE OF ELASTIC COMPRESSION - PRELIMINARY-RESULTS

Purpose: The purpose of this study was to assess the effects of the pa ssive 45-degree reverse Trendelenburg position and graduated compressi on stockings (GCS) on plasma tissue factor pathway inhibitor (TEPI) an d endothelin-1 levels in a group of volunteers. Methods: Ten healthy s ubjects lay on an examining table for 30 minutes while baseline measur ements were made. The table was then tilted to a 45-degree upright pos ition for 60 minutes, and measurements were repeated. On a different d ay, subjects were tilted again, but on this occasion they wore thigh-l ength GCS. Blood was drawn before and 60 minutes after tilting during both sessions, and plasma TFPI and endothelin-1 were obtained. Cross-s ectional areas of the calf medial gastrocnemius vein, before and after tilting, were measured by a duplex scanner. Results: Upright tilting induced a significant dilation of the medial gastrocnemius veins that was partially corrected by the use of elastic stockings. Similarly, en dothelin-1 levels significantly increased after tilting. The use of GC S did not modify these differences. On the other hand, although TFPI l evels were not affected by tilting without stockings, they were signif icantly elevated after tilting when GCS were used. Conclusions: Uprigh t passive tilting induces significant dilation of the deep calf veins and is associated with a significant increase in plasma levels of endo thelin-1, whereas TFPI levels remain unchanged. The use of elastic sto ckings reduces the degree of calf-distention but does not prevent an i ncrease in endothelin-1. TFPI levels are significantly increased after tilting when GCS are used. This might represent a previously unknown mechanism of action of elastic stockings with interesting potential fo r deep vein thrombosis prophylaxis. More studies are warranted in a la rger series to confirm these results.