Mixed ulcers

By | February 7, 2014

These are ulcers situated around the gaiter area in patients with a reduced arterial inflow, quantified by a reduced ankle-brachial pressure index (ABPI). This results in 2 different treatment philosophies:

1)  Treat the arterial inflow problem with angioplasty or bypass so that compression can be applied to heal the ulcer. This is sound advice but one cannot be sure whether the treatment benefit is from removal of the refluxing saphenous conduit or from the improved arterial inflow.

2)  Give compression anyway in the hope that the arterial circulation will not be impaired significantly by the compression and venous ulcer healing will occur as a result.

The problem with the latter solution is that compression is strongly contraindicated in patients with arterial disease and this dogma has been translated into hospital procedure and practice such that any breach may be liable to legal proceedings. However, there is evidence to suggest that compression may benefit both arterial and venous systems in many patients and that the strict rule of practice may deprive patients with optimal treatment for their ulcers. Nevertheless, strong compression should be avoided in mixed ulcers when the skin quality is fragile from the infirmity of age, especially around the fulcrum points of the malleoli or the anterior tibial border.

GIOVANNI MOSTI  About 15-20% of patients with venous leg ulcers have a reduced ABPI causing delayed healing. Although compression can improve venous haemodynamics in mixed ulcers it needs to be applied with caution in order not to reduce arterial inflow. In order to define a safe range of compression pressure that does not impede arterial flow we assessed 25 patients with mixed ulcers presenting with a mean ABPI of 0.57 and a systolic ankle pressure of 91.8 mm Hg.

Measurements taken included skin flow using laser Doppler flowmetry, toe pressures and TcPO2 on the dorsum of the foot. The measurements were carried out at baseline and after an inelastic bandage from the base of the toes to the popliteal area. These were with the different pressure ranges of 20-30, 30-40 and 40-50 mm Hg. Ejection fractions from the lower leg were also measured with bandages exerting a “safe pressure” not impeding arterial flow.

We concluded that when the ankle pressure is higher than 70 mm Hg, an external compression pressure of 20-30 or 30-40 mm Hg increases the arterial flow even in patients with a very low ABPI. Absolute ankle pressure values were more reliable than ABPI in assessing the individual risk concerning compression pressure. With this “modified pressure” inelastic bandages were still able to restore the reduced ejection fraction from the leg into its normal range. This confirmed a significant hemodynamic effect on the impaired venous hemodynamics even in the presence of a reduced pressure range in patients with a low ABPI.