Negative Pressure Wound Therapy Versus Standard Dressings on Closed Incisions for the Prevention of Surgical Site Infections After Vascular Surgery – A Systematic Review and Meta-analysis of Randomized Controlled Trials

Abstract

Introduction - Surgical site infections (SSI) after vascular surgery in the lower limb is a major concern. Negative pressure wound therapy (NPWT) on closed sutured surgical incisions has emerged as an innovative dressing that may reduce SSI. The few published randomized controlled trials (RCT) comparing closed NPWT with standard dressings after vascular surgery show inconsistent results. The aim of this systematic review with meta-analysis of RCTs was to evaluate the available evidence for closed NPWT after vascular surgery. Methods - A study protocol with defined search criteria settled in consultation with a faculty librarian was established according to the Cochrane handbook for systematic reviews and published in Prospero (Reg. Nr. CRD42018090298) a priori. The records generated by the systematic research of electronic databases for published and unpublished articles were screened for relevance (n=1183), by title and abstract (n=734) and in full-text (n=27) by two of the authors independently in the official Cochrane software Covidence© (Veritas Health Innovation, Melbourne, Australia) resulting in seven eligible studies. These were graded for bias according to the Cochrane tool for bias and assessed for size effects in Review Manager 5.3© (The Nordic Cochrane centre, Copenhagen). Results - This review involved 961 incisions from seven studies. Six studies used the PrevenaTM (Acelity, San Antonio, US) and one the PICOTM (Smith & Nephew, UK) dressing in the interventional NPWT arm. The meta-analysis for all surgical incisions after vascular surgery in the lower extremity showed a reduction of SSIs with NPWT; odds ratio (OR) 0.32 (95% CI: 0.21-0.47; p<0.00001, heterogeneity level: I2= 0%), using a random effect model (Figure 1). There was high risk of performance bias in all studies since all dressings were unblinded for patients and personnel. Two studies were only available as abstracts and risk of bias was unclear in five domains in each. In a sensitivity analysis of high-risk groins after lower limb revascularization exclusively in three studies (n=363), OR was 0.37 (95% CI: 0.22-0.63; p=0.0003, I2=0%), using a fixed effect model. In these three studies, there was a high or unclear risk of detection bias in two of the studies and a high risk of bias due to industry company funding in one of the studies. Conclusion - Closed NPWT after vascular surgical incisions in the lower limb reduced SSI compared to standard wound dressing. Heterogeneity between the included studies’ results was low. High or unclear risk of bias due to unblinded wound outcome assessment was a concern and these results therefore need to be interpreted with caution. Better and larger high-quality RCTs are needed.