Effects of External Leg Compression Devices on Healing and Blood Clotting

Intermittent Pneumatic Compression in the Lower Limbs: Systemic and Local Effects in Coagulation Status, Microcirculation, Tissue Metabolic Activity and Collagen Production.

This study aims to compare two different external calf compression devices applied in healthy individuals. These devices are commonly used in medical care in order to prevent the formation of blood clots, for example during immobilization after surgery. We aim to confirm the effects of external cyclic compression on healing and blood clotting and also to identify the one which is more effective.

Aims:

1. To confirm that IPC (intermittent pneumatic compression) has a positive effect on systemic coagulation status, tissue metabolic activity, collagen formation and tissue microcirculation.
2. To compare the above effect of two different IPC devices: one rapid calf-IPC which expels blood from the veins sharp and rapidly and one slow calf-IPC, which pumps the blood in a more gentle and progressive way. This study could also make implications on how the blood flow parameters could be interpreted in the clinical setting, as previous haemodynamic studies have explained the superiority of the rapid device in terms of peak velocity and the superiority of the slow device in terms of total ejected volume per individual stimulus.

Materials and Methods: 10-15 healthy individuals are planned to be recruited. The subjects will be lying in a prone position. A cuff connected with a Calf-IPC device will be wrapped around each calf and will be functioning for 120 minutes. Microdialysis catheters will be inserted with the tips about 1 mm from the volar side of each Achilles tendon. In addition, one adhesive sensor will be applied on each calf just distal to the lower part of the cuff, in order to measure tissue oxygen mixed saturation (INVOS). Blood samples will be taken via a venous catheter in antecubital fossa just before the application of the IPC, and at 30, 60 and 120 minutes. From the serum, several systemic coagulation factors will be measured (tissue plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI), tissue factor pathway inhibitor (TFPI), D-dimer, von Willebrand factor and factor VIIa). From the microdialysis diffusate , two groups of substances will be measured: a) metabolites, such as pyruvate and b) collagen macromolecules, such as procollagen type I and III.

The ultimate goal is to assess the role of different IPC patterns on deep venous thrombosis prevention and promotion of tissue healing.

Inclusion Criteria:

• Healthy individuals
• Male gender
• Age 18-60

Exclusion Criteria:

• Smoking
• Severe cardiovascular or renal disease causing pitting oedema
• Previous operation in the lower limbs affecting the vascular or lymphatic system