Inguinal Vascular Surgical Wound Protection by Incisional Negative Pressure Wound Therapy – A Randomized Controlled Trial – INVIPS Trial

Abstract

Introduction: SSIs are a major concern in open vascular procedures involving the inguinal region and lead to increased morbidity and mortality. Negative pressure wound therapy (NPWT) has been a reliable treatment option for infected and difficult to treat chronic wounds. Prophylactic NPWT on closed incisions to prevent surgical wound complications on the other hand is a newer approach and has shown promising results but the quality of evidence can be debated. This study aims to objectively evaluate if NPWT on sutured inguinal incisions after elective vascular surgery can decrease the incidence of surgical site complications. Methods: One hundred thirty-nine patients undergoing elective open vascular surgery with inguinal incisions received either NPWT or a standard dressing. Patients with bilateral incisions randomly received a dressing on one incision and the opposite dressing on the other. The primary endpoints were SSI or other wound complications at three months, assessed by wound care experts blinded to the treatment arm and using objective wound assessment criteria (ASEPSIS-score). Statistical analysis was performed on an intention-to-treat basis. Unilateral incisions were evaluated using Fisher's exact test. Bilateral incisions were seen as not independent from each other as infections of one surgical wound incision would increase risk for infection of the contralateral wound incision and were therefore analyzed using McNemar's test. Obtained p-values from analyses in the uni- and bilateral groups were combined to an overall p-value using Fisher's method for combining p-values. Results: The incidence of SSI was reduced in the NPWT group compared to the control group (11.9% versus 29.5% in the unilateral group [n=120], 5.3% versus 26.3% in the bilateral group [n=19] respectively; combined p=0.02). No differences regarding other surgical site complications were observed between the groups. There were no reported adverse events attributable to the NPWT dressing. Conclusion: NPWT on closed inguinal vascular surgical incisions in elective patients reduces the incidence of SSI. Disclosure: Around 5% of the funding for this study came from Smith and Nephew who is the manufacturer of the Negative Pressure Wound Therapy dressing used in this study.