Effects of Negative Pressure Wound Therapy on Perivascular Groin Infections after Vascular Surgery. Wound Healing, Cost-Effectiveness and Patient-Reported Outcome.

Abstract Background: Surgical site infection (SSI) in the groin after vascular surgery is common and deep perivascular infection leads to long periods of hospitalization, sometimes to amputation and/or death. Negative pressure wound therapy (NPWT) is increasingly used for treating wounds such as deep perivascular groin infections after vascular surgery, but there is no scientific evidence supporting its benefit over traditional wound therapy. Aims: To study the effect of NPWT on wound healing, complications, resource use, quality of life, cost-effectiveness, and to explore the experiences of patients with deep perivascular groin infections after vascular surgery undergoing NPWT at home Methods: A retrospective study was performed on consecutive patients undergoing NPWT between 2004 and 2006, and a randomized controlled trial was conducted between 2007 and 2011, where patients undergoing NPWT were compared to those treated with a traditional alginate dressing. Finally, a qualitative interview study was conducted between 2013 and 2014, in which patients undergoing NPWT in the outpatient setting were interviewed 7-14 days after discharge. Results: Twenty-eight patients/33 groins were studied in Study I, ten patients in each group in Studies II & III and 15 patients in Study IV. The median wound healing time was 55 days in Study I, 57 days in the NPWT group compared to 104 in the alginate group (p=0.026) in Studies II & III and 58 days in Study IV. The graft preservation rate in NPWT patients was 83%, 86% and 85% in Studies I, II/III and IV, respectively. Bacterial clearance from the wound was the same in the NPWT and alginate group in Studies II &III. One patient in the NPWT and one in the alginate group in Studies II &III had a severe bleeding from the femoral artery reconstruction site. Nine (43%) out of 21 groins with synthetic graft infections in Study I had an infection-related complication, compared to 0 (0%) out of 12 groins in those that did not have a synthetic graft infection (p=0.012), and non-healing wounds were associated with amputation (p=0.005) and death (p<0.001). A median of 21 (IQR 15-30) dressing changes were performed in the NPWT group, compared to 73 (IQR 51-98) (p<0.001) in the alginate group in Studies II & III. Compared to alginate therapy, NPWT saved the nurses 4.5 hours of work the first week after surgical revision in Study III. The total costs for the NPWT and alginate group in Study III were the same, of which 87% and 83%, respectively, were attributed to in-hospital costs. In Study III, estimation of Euroqol 5 Dimensions instrument and Brief Pain Inventory showed no differences at respective time points between the two groups. In Study IV an overall theme emerged from the descriptions of the experiences of patients with deep perivascular groin infection after vascular surgery undergoing NPWT at home, namely that it meant a transition from being a dependent patient to a person who needs to be involved and have self-care competence. A need to feel prepared for this before discharge from hospital was expressed. Lack of information and feelings of uncertainty prolonged the time before feeling confident in managing the treatment. The informants gradually accepted the need to be tied to a machine, became competent in its management, and found solutions to perform everyday tasks. Overall, it was a relief to be treated at home. Conclusion: NPWT in patients with deep perivascular SSI after vascular surgery is superior to traditional alginate therapy in terms of wound healing and cost-effectiveness. Patients expressed several benefits of treatment with NPWT at home. However, they experienced unnecessary stress and anxiety due to lack of information on the treatment and instruction concerning the equipment. Therefore, adequate information and education must be provided.