Quickshot: Changes in Interface Pressure of Multilayer Compression After One Week

Venous leg ulcers (VLUs) are signs of advanced chronic venous disease that can cause disability and complications. The Unna’s boot is widely used to treat VLUs and are typically worn 7 days at a time. While they can provide high interface pressure after application, minimal data is available to evaluate what happens to the interface pressure after application. The purpose of our study was to evaluate the changes in supine and standing interface pressures after 7 days of application.

Methods: This is an ongoing prospective study of patients with active VLUs who are treated with Unna’s boot. The study is for quality assurance to evaluate the interface pressure after application of an Unna’s boot at the time of application and at the time of follow up after 7 days. Demographic data was collected including age, gender, weight, and medical history. All patients had documented venous disease and an active venous ulcer. The Unna’s boot was applied by the same trained health care professional. The PicoPress® device was used to measure interface pressure in the supine and standing position. The pressure measuring probe was placed, under the compression bandage, in the most bulging area (B1) of the leg (10-15 cm above the inner malleolus). Patients with VLUs in the B1 position and those with recent ( < 3months) venous intervention were excluded from the study.

Results:

There were 10 limbs enrolled in 9 patients (8 left legs and 2 right legs). There were 8 men and 2 women with an average age of 69 years. The average BMI was 32 and all patients were C6 with average ulcer size of 5.2cm². Duplex findings showed venous disease in all patients (6 with superficial venous disease, 2 with combined superficial and deep disease and 2 with deep venous disease). There was a significant reduction in interface pressure (Table) both in the supine and standing position (p=0.0002, 95% CI 7.47-15.7). The mean static stiffness index (SSI) at time of application was 10.5mmHg and after 7 days it reduced to 6.2mmHg (p=0.09)

Conclusions:

Multi-layered compression bandage has been shown to have improved VLU healing rates compared to single layered bandages, presumably due to the higher interface pressure and improvement in venous hemodynamics. This study shows there is a significant reduction in interface pressure after 7 days. Larger studies with daily pressure measurements are required to identify at what point after application does significant reduction occur, which may change treatment protocols. Improvement in compression bandages that maintain high interface pressure over time can also improve time to wound healing.