Investigating the ability of an innovative point of care test to predict foot ulcer healing in people with diabetes

This study is primarily to determine if we can analyse matrix metalloproteinase MMP-9 (MMP-9) in foot ulcer wound fluid at the chair-side using a Point of care test (POCT) (InflammaDry®) during consultation at the time of treating the foot ulcer and to determine if this test can predict healing outcome. At each visit patients will receive standard clinical care in accordance with best practice guidelines for their diabetes related foot ulcer (Lazzarini PA, Raspovic A, Prentice J, Commons RJ, Fitridge RA, Charles J, Cheney J, Purcell N, Twigg SM, on behalf of the Australian Diabetes-related Foot Disease Guidelines & Pathways Project. 2021 Australian evidence-based guidelines for diabetes-related foot disease; version 1.0. Brisbane, Australia: Diabetes Feet Australia, Australian Diabetes Society; 2021). Collection of the wound fluid for the POCT will take approximately 5 minutes (see method & equipment below). Once the podiatrist has taken the wound fluid they will continue with the clinical management of the patient and the principal investigator (Senior Podiatrist) will prepare the wound fluid and apply it to the POCT. The POCT is not being used for any clinical decision making in the current proposal but in assessment of its feasibility and accuracy as a point of care test. Participants with a diabetes related foot ulcer will undertake a four week run-in period at the interdisciplinary High Risk Foot Service (iHRFS) managed with optimized standard care. After informed consent is obtained participants will be seen every 1 to 2 weeks based on their clinical need during this 4-week run-in period to confirm eligibility. The study visit will occur in conjunction with the iHRFS appointment (duration of 60 minutes). At week 0 and week 4 the POCT will be used to measure MMP-9 obtained from wound fluid samples and performed by a podiatrist at the iHRFS. For ulcers treated with dried human placental derived allograft (Revita), we also plan to determine MMP-9 by POCT at week 8 (4 weeks after Revita® application) to obtain some indication as to whether the MMP-9 POCT may reflect a beneficial effect of Revita in ulcer healing. At the end of the four week run-in period patients who have complied with using the prescribed offloading device, have less than 50% reduction in wound size as measured by macroscopic wound planimetry (ulcer tracings on acetate paper with marker pens - 2 Dimensional measurement), will be offered the dried human placental allograft (Revita). If the patient declines Revita therapy then they will remain in the study and receive standard care. Revita is a dried, sterile human tissue allograft derived from intact human placental membrane. The podiatrist will undertake sharp wound debridement (removal of all non-viable tissue from the peri-wound edge and wound base) and irrigation of the wound using 10mls of sterile saline. Revita (primary wound dressing) is cut to the shape of the ulcer and placed in the wound cavity by the treating podiatrist at the iHRFS. Revita is required to stay in place for 14 days. To ensure this remains undisturbed a non-medicated ointment dressing (Atrauman) will be placed over the allograft and secured with steri-strips. The secondary dressing will be selected based on exudate levels (biatain foam or zetuvit) & blue-line tubifast to hold in place. The secondary dressing will be changed every second day or twice a week dependent on the exudate levels by the patient, carer or nurse. Re-application of Revita will be based on the podiatrists assessment of the wound bed at week 6,8,10,12,14 at the High risk foot service . If the patient declines this dressing they can continue in the study and will receive the best available standard care. A maximum of 6 separate placental derived allografts may be administered over a 14 week period. The frequency of application is determined by clinical assessment of the treating clinician and this is in-line with manufacturer advice and available evidence. Point Of Care Test Method & Equipment: 1. Immerse the Paper Point in multiple locations along the inside of the wound to collect the wound fluid until saturation (fluid reaching to the top blue line “24” of the Paper Point). 2. Transfer the Paper Point into a microtube with 500 µL of PBS. 3. Soak for 5 minutes at room temperature. 4. Quick mix by vortex 10 seconds. 5. Transfer the tube into a centrifuge and spin at 5000rpm for 5 minutes. 6. Remove the Paper Point from the tube and discard it. 7. Use a transfer pipette to collect wound fluid from the tube (~10 µL) and add to the sampling fleece of the Sample Collector until saturated, when the fleece will glisten and may turn patchy pink. 8. Close the Sample Collector into the Test Cassette. Press firmly where indicated . A double-click means the test is properly assembled. 9. Label the test Cassette with the patients REDcap number, MRN and DOB. 10. Immerse the absorbent tip into the provided buffer vial for a minimum of 20 seconds until a purple fluid wave is observed moving across the result window. 11. Replace the protective cap and lay the test flat on a horizontal surface. After 10 minutes, read the test results. If the test is negative after 10 minutes, allow an additional 5-10 minutes before reading test results.