The concentration of high molecular weight compounds in interstitial tissue fluid: a study in patients with post-reconstructive leg oedema.

Objectives: To study whether relative changes in the concentration of different proteins of the subcutaneous interstitial tissue fluid in patients with postreconstructive leg oedema could give information on the integrity of the capillary wall following vascular reconstruction.

Materials: Sixteen patients developed ipsilateral leg oedema following femoropopliteal (n = 14) or femorotibial (n = 2) bypass surgery for intermittent claudication (n = 10) or critical lower limb ischaemia (n = 6) caused by obliterating atherosclerosis.

Methods: The leg volume increase was measured according to the formula of a truncated cone. The blister suction method was used for sampling of subcutaneous interstitial tissue fluid. The concentration of albumin, transferrin, immunoglobulin G and alpha 2-macroglobulin of serum and blister fluid was measured with nephelometry.

Results: Seven days postoperatively the mean leg volume increase was 32% (19.8%) in the operated leg compared to the contralateral side (p < 0.01). In the blister fluid each of the proteins had a significantly higher concentration in the operated leg compared to the control leg. This concentration difference was relatively larger for the proteins with the highest molecular weight, immunoglobulin G (p = 0.006) and alpha 2-macroglobulin (p = 0.002).

Conclusions: A relatively larger concentration difference of the bigger molecules in the subcutaneous interstitial tissue fluid in patients with post-reconstructive leg ocdema suggests increased capillary permeability to plasma proteins following vascular reconstruction.