MedicalResearch.com Interview with:
Mariusz Kowalewski, MD
Department of Cardiac Surgery, Dr Antoni Jurasz Memorial University Hospital
Bydgoszcz,
Systematic Investigation and Research on Interventions and Outcomes
Medicine Research Network, Poland
Medical Research: What is the background for this study? What are the main findings?
Dr. Kowalewski: Sternal wound infections occurring after heart surgery performed via median sternotomy, and in particular, after coronary artery bypass grafting (CABG), although rare, still pose serious postoperative complications that increase the length of hospital stay and healthcare costs. One of many ways to prevent them from happening, except from optimal glucose control, tight-fixed closure of the sternum at the end of surgery and perioperative iv. antibiotics, is to insert a gentamicin collagen sponge between two sternal edges, just before wiring them together. High local concentrations of gentamicin were shown to eliminate any microbial growth in the area, in the same time, not affecting the kidneys, as would be the case with systemic administration. Gentamicin sponges are widely used in orthopadic, gastro-intestinal and vascular surgery and were shown to reduce postoperative infection rates. Although extensively tested in the field of heart surgery, findings of one recent multicenter study have questioned their true benefit. We aimed to perform a comprehensive meta-analysis of studies assessing the efficacy of implantable gentamicin-collagen sponges in sternal wound infection prevention.
After screening multiple databases, a total of 14 studies (N = 22,135 patients, among them 4 randomized controlled trials [N = 4,672 pts]) were included in the analysis. Implantable gentamicin-collagen sponges significantly reduced the risk of sternal wound infection by approximately 40% when compared with control (risk ratio [RR], 0.61; 95% confidence interval [CI], 0.39-0.98; P = .04 for randomized controlled trials and RR, 0.61; 95% CI, 0.42-0.89; P = .01 for observational studies). A similar, significant benefit was demonstrated for deep sternal wound infection (RR, 0.60; 95% CI, 0.42-0.88; P = .008) and superficial sternal wound infection (RR, 0.60; 95% CI, 0.43-0.83; P = .002). The overall analysis revealed a reduced risk of mediastinitis (RR, 0.64; 95% CI, 0.45-0.91; P = .01). The risk of death was unchanged.
In addition, we investigated, by means of meta-regression, the correlation between sternal wound infections and extent to which the bilateral internal thoracic artery (BITA) was harvested. We found that the benefit provided by the gentamicin sponge was attenuated when BITA was harvested; these results suggest that another potentially preventive measure must be taken in such patients, as with severely reduced blood supply to the sternum (as is the case with BITA), sponge itself might not be enough to prevent wound infection.
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