Wound Bed Preparation With a Dermal Substitute (Hyalomatrix® PA) Facilitates Re-epithelialization and Healing

Results of a Multicenter, Prospective, Observational Study on Complex Chronic Ulcers (The FAST Study)

Carlo Caravaggi, MD; Francesco Grigoletto, ScD; Nicolò Scuderi, MD

Disclosures

Wounds. 2011;23(8):228-235. 

In This Article

Abstract and Introduction

Abstract

The FAST study evaluated the performance and safety of Hyalomatrix® PA (a dermal substitute) in the treatment of chronic wounds of different etiology. Methods. This was a multicenter, prospective, observational study involving 70 Italian centers and 262 elderly patients. Patients were observed from the start of treatment with a dermal substitute (Hyalomatrix® PA [HPA]) until healthy dermal tissue suitable for a thin autograft was visible or until the growth of new epithelium from the wound edge was reported. Tracking the wound edge advancement was used to assess the dermal substitute's performance. The main endpoint was the reduction in threshold area (≥ 10%) of the ulcer. Treated ulcers were characterized as follows: 46% vascular, 25% diabetic foot, 12% traumatic wounds, 2% pressure ulcers and 15% other. Results. Re-epithelization (≥ 10%) was achieved in 83% of ulcers in a median time of 16 days. Twenty-six percent (26%) of wounds achieved 75% re-epithelization within the 60-day follow-up period using only HPA treatment. A follow-up showed that 84% of ulcers achieved complete re-epithelialization by secondary intention. Conclusion. These findings indicate that HPA is a safe and effective dermal substitute. The results show that the re-epithelization process following HPA treatment is independent upon etiology, area, and depth of the ulcer, and treatment is more effective on acute ulcer formation.

Introduction

The aim of treating any type of wound is to create an environment that promotes normal and timely healing. A chronic wound is a wound that is delayed in one of the wound-healing stages (usually the inflammatory stage) and cannot progress any further. A chronic wound leaves the patient at risk of infection, hospitalization and potential amputation of the infected limbs.[1]

These types of wounds are highly prevalent and expensive and their costs are predicted to increase annually.[2,3] Unfortunately, the healing process is extremely slow, thus underlining the importance of investigating novel candidate treatment regimes specifically aimed at accelerating the healing process.

Current standard treatment for a chronic ulcer consists of surgical debridement, treatment of infection, and surgical or medical correction of any deficit to arterial blood supply. More recently, the concept of a clean moist environment has been widely accepted in the treatment of ulcers. Moreover, the moisture-retentive dressings provide a moist environment that stimulates capillary growth, facilitates autolytic debridement, and accelerates ulcer healing.[4] However, in some cases, standard care therapies including compression therapy in venous ulcers, off-loading in diabetic neuropathic ulcers, wound cleansing, debridement, infection management, are insufficient.[5,6]

Over the past 10 years, in order to stimulate the healing process in non-healing chronic wounds, different types of advanced dressings, acellular dermal-epidermal matrices, and bioengineered skin substitutes have been applied with varying success.[7]

Hyaluronic acid (HA) is a skin polymer used in tissue engineering to facilitate healing.[8] In slow-healing wounds such as chronic wounds where there is little granulation tissue, there is often a deficiency of hyaluronic acid. Such a deficit leads to insufficient regeneration of connective tissue and poor formation of new blood vessels, as HA appears to be a rate-limiting substrate in wound healing.[9] Exogenous hyaluronic acid applied to a debrided wound keeps it moist and ensures a high concentration at the site of action.[10] It is widely recognized that hyaluronic acid plays a multifaceted role in each stage of wound healing (inflammation, granulation tissue formation, re-epithelization, and remodeling) stimulating angiogenesis, fibroblast migration, and the orderly deposition of essential components of the extracellular matrix.[11–19]

Hyalomatrix PA® ([HPA], Anika Therapeutics S.r.l., Abano Terme, Italy) is a non-woven pad composed of HYAFF® 11, which is an esterified derivative of hyaluronic acid coupled with a layer of medical grade silicone. The silicone layer controls water vapor loss avoiding an excessive loss of fluids and acts as a semi-permeable barrier to the external agents.

The matrix of HYAFF 11 is a biodegradable (transforms to gel) and bioabsorbable material, which following degradation, releases a high concentration of hyaluronic acid at the wound site.

HPA, an acellular dermal substitute, was conceived and designed to act as a dermal substitute to prepare the wound bed for subsequent grafting on extensive, deep skin burns, and to treat post-traumatic or post-surgical wounds where there is partial or total loss of dermal tissue. It is specifically designed to replace the dermis and provides a 3-dimensional matrix facilitating cellular invasion and capillary growth. Promising results obtained in the treatment of these acute wounds have prompted an evaluation of its application to chronic wounds.[20–23]

Recent clinical experience on the use of HPA led to the development of a protocol for this system regarding treatment of chronic wounds (diabetic foot, vascular, and post-surgical ulcers), which defines the indications, timing of application, and overall ulcer management.

In slow-healing wounds, the high local concentration of hyaluronic acid released on the site following degradation of HYAFF matrix kick starts the healing process recreating an acute wound that can progress through the normal stages of healing.

Clinically, it is possible to see a chronic wound turned in acute wound assessing the presence of the good quality granulation tissue and of the re-epithelialization process. The evidence of edge stimulation at the wound margin is recognized as a useful indicator of the healing process.[24–27] Therefore, to objectively evaluate the performance of HPA, the analysis of the data was based on the principle of the epithelial (edge) advancement. The "wound edge effect" was assessed by measuring advancement of the wound edge, and a threshold area reduction of the ulcer (epithelial advancement) of ≥ 10% was considered as an endpoint measure.

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