The impact of incisional negative pressure wound therapy on the wound healing process after midline sternotomy

The prophylactic use of negative-pressure wound therapy after cardiac surgery: a meta-analysis

Surgical site infections (SSIs) pose a frequent complication in cardiac surgery patients and lead to increased patient discomfort and extended hospitalization. This meta-analysis aimed to evaluate the protective role of single-use negative-pressure wound therapy (sNPWT) devices on closed surgical wounds after cardiac surgery, and explored their potential preventive application across all cardiac surgery patients. A comprehensive literature search was conducted on ScienceDirect, focusing on studies related to "negative pressure wound therapy" or "PICO negative pressure wound therapy" combined with "cardiac surgery" or "sternotomy," published between 2000 and 2022. Inclusion criteria encompassed case-control studies comparing sNPWT with traditional dressings on closed cardiac surgical incisions in adult patients undergoing median sternotomy without immediate postoperative infective complications, with available details on SSIs. A retrospective analysis of cases treated with sNPWT in our centre was also performed. The meta-analysis revealed a protective role of sNPWT, indicating a 44% risk reduction in overall SSIs (odds ratio 0.56) and a 40% risk reduction in deep wound infections (odds ratio 0.60). Superficial wound infections, however, showed non-significant protective effects. A single-centre study aligned with the meta-analysis findings, confirming the efficacy of sNPWT and was included in the meta-analysis. In conclusion, the meta-analysis and the single-centre study collectively support the protective role of negative pressure wound therapy against overall and deep SSIs, suggesting its potential prophylactic use on all cardiac surgery populations.

The negative pressure wound therapy for prevention of sternal wound infection: Can we reduce infection rate after the use of bilateral internal thoracic arteries? A systematic literature review and meta-analysis

BACKGROUND

Negative pressure wound therapy (NPWT) is traditionally used to treat postoperative wound infections. However, its use in closed wound sternotomy post cardiac surgery in high-risk patients has become increasingly popular. The potential preventive benefit of reducing sternal wound infections has been recently acknowledged. Bilateral internal mammary artery (BIMA) grafts are used in coronary artery bypass grafting but have been associated with an increased risk of sternal wound infections (SWIs).

OBJECTIVES

This systematic analysis examines whether NPWT can reduce the incidence of SWI following BIMA grafts, leading to more patients benefiting from the better survival outcome associated with BIMA grafting.

METHOD

A comprehensive systematic search and meta-analysis were performed to identify studies on the use of NPWT in closed wound sternotomy. Ovid MEDLINE (in-process and other nonindexed citations and Ovid MEDLINE 1990 to present), Ovid EMBASE (1990 to present), and The Cochrane Library (Wiley), PubMed, and Google Scholar databases were searched from their inception to May 2022 using keywords and MeSH terms. Thirty-four articles from 1991 to May 2022 were selected.

RESULT

Three studies reported on the outcome of NPWT following BIMA grafting. The pooled analysis did not show any significant difference in the incidence of sternal wound infection between NPWT and standard dressing (RR 0.48 95% CI 0.17-1.37; P = 0.17) with substantial heterogeneity (I2 65%). Another seven studies were found comparing the outcome of SWI incidence of negative pressure closed wound therapy with conventional wound therapy in patients undergoing adult cardiac surgery. The pooled analysis showed that NPWT was associated with a low risk of SWIs compared to conventional dressing (RR 0.47 95% CI 0.36-0.59; P < 0.00001), with low heterogeneity (I2 1%).

CONCLUSION

The literature identified that NPWT significantly decreased the incidence of sternal wound complications when applied to sutured sternotomy incisions in high-risk patients, and in some cases, it eliminated the risk. However, the inadequate number of randomized controlled trials assessing the effectiveness of NPWT in BIMA grafting emphasizes the need for further, robust studies.

Efficacy of incisional negative pressure therapy in preventing post-sternotomy wound complications

BACKGROUND

Sternal wound infections represent a source of significant morbidity and mortality following median sternotomy. The use of incisional negative pressure wound therapy in prevention has yet to be elucidated.

METHODS

A retrospective study was conducted before and after a universal wound care protocol was implemented including the prophylactic use of negative pressure wound therapy (NPWT). The primary endpoint was sternal infections within 90 days of the index operation.

RESULTS

In the control period, there was a 3.0% rate of sternal infection within 90 days compared to 0.8% in the intervention period (p < 0.001). An odds ratio of 0.25 (95% confidence interval 0.11, 0.57; p < 0.001) in the intervention period as compared to the control period was demonstrated.

CONCLUSIONS

The use of a standardized wound care protocol including the universal application of NPWT for patients undergoing cardiac surgery with median sternotomy was an independent predictor of decreased rates of sternal infection.

Effects of negative pressure wound therapy on surgical site wound infections after cardiac surgery: A meta-analysis

We conducted a comprehensive analysis to evaluate the benefits of negative pressure wound therapy (NPWT) versus traditional dressings in preventing surgical site infections in patients undergoing cardiac surgery. We thoroughly examined several databases, including PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), VIP, Chinese Biomedical Literature Database (CBM) and Wanfang, from inception until July 2023. Two independent researchers were responsible for the literature screening, data extraction and quality assessment; analyses were performed using RevMan 5.4 software. Thirteen studies comprising 8495 patients were deemed relevant. A total of 2685 patients were treated with NPWT, whereas 5810 received conventional dressings. The findings revealed that NPWT was more effective in reducing surgical site infections after cardiac surgery than conventional dressings (4.88% vs. 5.87%, odds ratio [OR]: 0.50, 95% confidence intervals [CIs]: 0.40-0.63, p < 0.001). Additionally, NPWT was more effective in reducing deep wound infections (1.48% vs. 4.15%, OR: 0.36, 95% CI: 0.23-0.56, p < 0.001) and resulted in shorter hospital stays (SMD: -0.33, 95% CIs: -0.54 to -0.13, p = 0.001). However, the rate of superficial wound infections was not significantly affected by the method of wound care (3.72% vs. 5.51%, OR: 0.63, 95% CI: 0.32-1.23, p = 0.180). In conclusion, NPWT was shown to be advantageous in preventing postoperative infections and reducing hospital stay durations in patients undergoing cardiac surgery. Nonetheless, given the limitations in the number and quality of the included studies, further research is recommended to validate these findings.

Incisional negative pressure wound therapy for the prevention of surgical site infection: an up-to-date meta-analysis and trial sequential analysis

Background

The evidence on prophylactic use of negative pressure wound therapy on primary closed incisional wounds (iNPWT) for the prevention of surgical site infections (SSI) is confusing and ambiguous. Implementation in daily practice is impaired by inconsistent recommendations in current international guidelines and published meta-analyses. More recently, multiple new randomised controlled trials (RCTs) have been published. We aimed to provide an overview of all meta-analyses and their characteristics; to conduct a new and up-to-date systematic review and meta-analysis and Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessment; and to explore the additive value of new RCTs with a trial sequential analysis (TSA).

Methods

PubMed, Embase and Cochrane CENTRAL databases were searched from database inception to October 24, 2022. We identified existing meta-analyses covering all surgical specialties and RCTs studying the effect of iNPWT compared with standard dressings in all types of surgery on the incidence of SSI, wound dehiscence, reoperation, seroma, hematoma, mortality, readmission rate, skin blistering, skin necrosis, pain, and adverse effects of the intervention. We calculated relative risks (RR) with corresponding 95% confidence intervals (CI) using a Mantel-Haenszel random-effects model. We assessed publication bias with a comparison-adjusted funnel plot. TSA was used to assess the risk of random error. The certainty of evidence was evaluated using the Cochrane Risk of Bias-2 (RoB2) tool and GRADE approach. This study is registered with PROSPERO, CRD42022312995.

Findings

We identified eight previously published general meta-analyses investigating iNPWT and compared their results to present meta-analysis. For the updated systematic review, 57 RCTs with 13,744 patients were included in the quantitative analysis for SSI, yielding a RR of 0.67 (95% CI: 0.59-0.76, I2 = 21%) for iNPWT compared with standard dressing. Certainty of evidence was high. Compared with previous meta-analyses, the RR stabilised, and the confidence interval narrowed. In the TSA, the cumulative Z-curve crossed the trial sequential monitoring boundary for benefit, confirming the robustness of the summary effect estimate from the meta-analysis.

Interpretation

In this up-to-date meta-analysis, GRADE assessment shows high-certainty evidence that iNPWT is effective in reducing SSI, and uncertainty is less than in previous meta-analyses. TSA indicated that further trials are unlikely to change the effect estimate for the outcome SSI; therefore, if future research is to be conducted on iNPWT, it is crucial to consider what the findings will contribute to the existing robust evidence.

Funding

Dutch Association for Quality Funds Medical Specialists.

Continuous NPWT Regulates Fibrosis in Murine Diabetic Wound Healing

Scarring is associated with significant morbidity. The mechanical signaling factor yes-associated protein (YAP) has been linked to Engrailed-1 (En1)-lineage positive fibroblasts (EPFs), a pro-scarring fibroblast lineage, establishing a connection between mechanotransduction and fibrosis. In this study, we investigate the impact of micromechanical forces exerted through negative pressure wound therapy (NPWT) on the pathophysiology of fibrosis. Full-thickness excisional dorsal skin wounds were created on diabetic (db/db) mice which were treated with occlusive covering (control) or NPWT (continuous, −125 mmHg, 7 days; NPWT). Analysis was performed on tissue harvested 10 days after wounding. NPWT was associated with increased YAP (p = 0.04) but decreased En1 (p = 0.0001) and CD26 (p < 0.0001). The pro-fibrotic factors Vimentin (p = 0.04), α-SMA (p = 0.04) and HSP47 (p = 0.0008) were decreased with NPWT. Fibronectin was higher (p = 0.01) and collagen deposition lower in the NPWT group (p = 0.02). NPWT increased cellular proliferation (p = 0.002) and decreased apoptosis (p = 0.03). Western blotting demonstrated increased YAP (p = 0.02) and RhoA (p = 0.03) and decreased Caspase-3 (p = 0.03) with NPWT. NPWT uncouples YAP from EPF activation, through downregulation of Caspace-3, a pro-apoptotic factor linked to keloid formation. Mechanotransduction decreases multiple pro-fibrotic factors. Through this multifactorial process, NPWT significantly decreases fibrosis and offers promising potential as a mode to improve scar appearance.

Negative-Pressure Wound Therapy for Prevention of Sternal Wound Infection after Adult Cardiac Surgery: Systematic Review and Meta-Analysis

The results of current studies are not conclusive on the efficacy of incisional negative-pressure wound therapy (NPWT) for the prevention of sternal wound infection (SWI) after adult cardiac surgery. A systematic review of the literature was performed through PubMed, Scopus and Google to identify studies which investigated the efficacy of NPWT to prevent SWI after adult cardiac surgery. Available data were pooled using RevMan and Meta-analyst with random effect models. Out of 191 studies retrieved from the literature, ten fulfilled the inclusion criteria and were included in this analysis. The quality of these studies was judged fair for three of them and poor for seven studies. Only one study was powered to address the efficacy of NPWT for the prevention of postoperative SWI. Pooled analysis of these studies showed that NPWT was associated with lower risk of any SWI (4.5% vs. 9.0%, RR 0.54, 95% CI 0.34–0.84, I2 48%), superficial SWI (3.8% vs. 4.4%, RR 0.63, 95% CI 0.29–1.36, I2 65%), and deep SWI (1.8% vs. 4.7%, RR 0.46, 95% CI 0.26–0.74, I2 0%), but such a difference was not statistically significant for superficial SWI. When only randomized and alternating allocated studies were included, NPWT was associated with a significantly lower risk of any SWI (3.3% vs. 16.5%, RR 0.22, 95% CI 0.08–0.62, I2 0%), superficial SWI (2.6% vs. 12.4%, RR 0.21, 95% CI 0.06–0.69, I2 0%), and deep SWI (1.2% vs. 4.8%, RR 0.17, 95% CI 0.03–0.95, I2 0%). This pooled analysis showed that NPWT may prevent postoperative SWI after adult cardiac surgery. NPWT is expected to be particularly useful in patients at risk for surgical site infection and may significantly reduce the burden of resources needed to treat such a complication. However, the methodology of the available studies was judged as poor for most of them. Further studies are needed to obtain conclusive results on the potential benefits of this preventative strategy.

The impact of incisional negative pressure wound therapy on the wound healing process after midline sternotomy

Previous studies have reported that the use of incisional negative pressure wound therapy (INPWT) might reduce the incidence of wound infections, although its mechanism remains unknown. We designed a prospective study to explore the effects of INPWT on different stages of the wound healing process. After meeting the inclusion criteria, 108 patients were enrolled. Based on exclusion criteria four patients were excluded and 104 patients were randomised into two groups. INPWT was applied after primary closure of the midline sternotomy in the study group (n = 52), while conventional wound dressing was applied in the control group (n = 52). We documented the incidence of deep sternal wound infections and analysed the pre‐ and postoperative inflammatory biomarkers and scar size in both groups. No wound infections were observed in the study group compared with six cases (11.1%) in the control group, (P = .026). No significant differences were observed in the inflammatory biomarkers between the groups. Scar size was significantly smaller in the study group. We concluded that INPWT has less effect on the inflammatory phase and appears to have more effect on the proliferation phase through pronounced scar formation.