Venous leg ulcers occur due to increased venous pressure that causes protein and white blood cells to leak out of the capillaries of the lower leg into the surrounding tissue. These proteins surround the blood vessels decreasing the capacity of the blood to supply oxygen to the tissue, while, simultaneously, the white blood cells increase the inflammatory cascade in the soft tissue. There are several reasons for the increased hydrostatic pressure in the lower extremity; reflux of the deep and/or superficial venous system(s), obstruction of the deep system, calf muscle pump failure – secondary to obesity, change in ankle range of motion, and gait disturbance, or a combination of any three. Diagnosis of the type of venous disease and the quality of the arterial perfusion to the tissue needs to be elucidated earlier than later, prior to the initiation of any type of therapy. Repeated ischemia with inflammation causes the tissue to eventually break down and the skin to ulcer. Venous leg ulcers account for approximately eleven percent of all chronic wounds treated world-wide, while in some countries they account for up to three percent of all health care expenditures, this is due to their frequency and chronic nature. Studies have shown that approximately 50 percent of venous leg ulcers are healed after four months of standard therapy, and only 80 percent at two years. The cornerstone of the treatment for venous leg ulcers is compression, with a goal of achieving 40 mm of mercury compression at the ankle. There are two to four layer wraps as well as Velcro-based non-elastic systems currently available and when professionally applied as indicated, these various systems have comparable positive outcomes. However, it should be noted that it takes three to four months to heal the average venous leg ulcer. Once the patient has a closed ulcer it is imperative that they continue to use a compression garment that provides at least 30 mm of mercury at the ankle, if the patient does not wear a compression garment they have a 70 percent chance of re-opening the ulcer in six months.
Furthermore, it has been documented that patients that allow the debridement of a venous leg ulcer do better than those that do not. It has also been noted that patients who do not display a forty percent decease in the size of their ulcer after four weeks of good compression are much less likely to heal than those that do show such a decrease. Therefore, failure to create a reduction in the area after 4 weeks is thought to an indication for the addition of a cellular or tissue based therapy. Other indicators of poor prognosis that may require aggressive early therapy are an ulcer with a duration of greater than 50 weeks and/or size greater than 12 cm2. Finally, surgical or endo-venous correction of superficial venous reflux is reserved for patients that have superficial reflux as a cause of their venous ulcer. Currently, such interventions are only proven to prevent recurrence of healed ulcers and not as a means to increased healing of open ulcers.
Clinical practice guidelines of the Society for Vascular Surgery (SVS) and the American Venous Forum (AVF): Management of venous leg ulcers, Volume 60, Issue 2, Supplement, p1S-90S August 2014 Ed. TF O'Donnell, MA Passman