Direct sternal administration of Vancomycin and Gentamicin during closure prevents wound infection

Aortic Valve Infective Endocarditis Complicated by Annular Abscess: Antibiotics in the Abscess Cavity

OBJECTIVES

Infective endocarditis of the aortic valve complicated by annular abscess is a challenging problem and often requires patch reconstruction after surgical debridement of the abscess cavity. Filling the remaining cavity with antibiotics is advocated to prevent recurrent endocarditis. This study aimed at evaluating the role of local antibiotics in patients with aortic valve infective endocarditis complicated by annular abscess.

METHODS

Between January 2012 and December 2021, all consecutive patients with aortic valve infective endocarditis complicated by annular abscess undergoing cardiac surgery and annular patch reconstruction were included. Patients receiving local antibiotics were compared with patients without local antibiotics. The primary endpoints were the incidence of recurrent endocarditis, re-operation, and mortality during two-year follow-up.

RESULTS

A total of 41 patients with aortic valve infective endocarditis complicated by annular abscess underwent surgical patch reconstruction after radical debridement. In total, 20 patients received local antibiotics in the abscess cavity and 21 patients were treated without local antibiotics. The most common causative microorganisms were the staphylococci species and the most common location of the abscess was the non-coronary annulus. During two-year follow-up, one patient in each group developed recurrent endocarditis (p > 0.99) and both patients were reoperated (p > 0.99). Two-year mortality was 30% in the local antibiotic group and 24% in the control group (p = 0.65).

CONCLUSIONS

Radical debridement and patch reconstruction of the aortic annulus in patients with aortic valve infective endocarditis complicated by annular abscess is an effective surgical strategy. Filling of the remaining abscess cavity with antibiotic seems not to affect the rate of recurrent endocarditis, reoperation, and mortality during two-year follow-up.

Regional antibiotic delivery for sternal wound infection prophylaxis a systematic review and meta-analysis of randomized controlled trials

Despite evidence suggesting the benefit of prophylactic regional antibiotic delivery (RAD) to sternal edges during cardiac surgery, it is seldom performed in clinical practice. The value of topical vancomycin and gentamicin for sternal wound infections (SWI) prophylaxis was further questioned by recent studies including randomized controlled trials (RCTs). The aim of this systematic review and meta-analysis was to comprehensively assess the safety and effectiveness of RAD to reduce the risk of SWI.We screened multiple databases for RCTs assessing the effectiveness of RAD (vancomycin, gentamicin) in SWI prophylaxis. Random effects meta-analysis was performed. The primary endpoint was any SWI; other wound complications were also analysed. Odds Ratios served as the primary statistical analyses. Trial sequential analysis (TSA) was performed.Thirteen RCTs (N = 7,719 patients) were included. The odds of any SWI were significantly reduced by over 50% with any RAD: OR (95%CIs): 0.49 (0.35-0.68); p < 0.001 and consistently reduced in vancomycin (0.34 [0.18-0.64]; p < 0.001) and gentamicin (0.58 [0.39-0.86]; p = 0.007) groups (psubgroup = 0.15). Similarly, RAD reduced the odds of SWI in diabetic and non-diabetic patients (0.46 [0.32-0.65]; p < 0.001 and 0.60 [0.44-0.83]; p = 0.002 respectively). Cumulative Z-curve passed the TSA-adjusted boundary for SWIs suggesting adequate power has been met and no further trials are needed. RAD significantly reduced deep (0.60 [0.43-0.83]; p = 0.003) and superficial SWIs (0.54 [0.32-0.91]; p = 0.02). No differences were seen in mediastinitis and mortality, however, limited number of studies assessed these endpoints. There was no evidence of systemic toxicity, sternal dehiscence and resistant strains emergence. Both vancomycin and gentamicin reduced the odds of cultures outside their respective serum concentrations' activity: vancomycin against gram-negative strains: 0.20 (0.01-4.18) and gentamicin against gram-positive strains: 0.42 (0.28-0.62); P < 0.001. Regional antibiotic delivery is safe and effectively reduces the risk of SWI in cardiac surgery patients.

Topical vancomycin for sternal wound infection prophylaxis. A systematic review and updated meta-analysis of over 40,000 cardiac surgery patients

BACKGROUND

Despite guideline recommendations, routine application of topical antibiotic agents to sternal edges after cardiac surgery is seldom done. Recent randomized controlled trials have also questioned the effectiveness of topical vancomycin in sternal wound infection prophylaxis.

METHODS

We screened multiple databases for observational studies and randomized controlled trials assessing the effectiveness of topical vancomycin. Random effects meta-analysis and risk-profile regression were performed, and randomized controlled trials and observational studies were analyzed separately. The primary endpoint was sternal wound infection; other wound complications were also analyzed. Risk ratios served as primary statistics.

RESULTS

Twenty studies (N = 40,871) were included, of which 7 were randomized controlled trials (N = 2,187). The risk of sternal wound infection was significantly reduced by almost 70% in the topical vancomycin group (risk ratios [95% confidence intervals]: 0.31 (0.23-0.43); P < .00001) and was comparable between randomized controlled trials (0.37 [0.21-0.64]; P < .0001) and observational studies (0.30 [0.20-0.45]; P < .00001; Psubgroup = .57). Topical vancomycin significantly reduced the risk of superficial sternal wound infections (0.29 [0.15-0.53]; P < .00001) and deep sternal wound infections (0.29 [0.19-0.44]; P < .00001). A reduction in the risk of mediastinitis and sternal dehiscence risks was also demonstrated. Risk profile meta-regression showed a significant relationship between a higher risk of sternal wound infection and a higher benefit accrued with topical vancomycin (ß-coeff. = -0.00837; P < .0001). The number needed to treat was 58.2. A significant benefit was observed in patients with diabetes mellitus (risk ratios 0.21 [0.11-0.39]; P < .00001). There was no evidence of vancomycin or methicillin resistance; on the contrary, the risk of gram-negative cultures was reduced by over 60% (risk ratios 0.38 [0.22-0.66]; P = .0006).

CONCLUSION

Topical vancomycin effectively reduces the risk of sternal wound infection in cardiac surgery patients.

Combined Band and Plate Fixation as a New Individual Option for Patients at Risk of Sternal Complications after Cardiac Surgery: A Single-Center Experience

Due to the advent of interventional therapies for low- and intermediate-risk patients, case complexity has increased in cardiac surgery over the last decades. Despite the surgical progress achieved to keep up with the increase in the number of high-risk patients, the prevention of sternal complications remains a challenge requiring new, individualized sternal closure techniques. The aim of this study was to evaluate the safety and feasibility, as well as the in-hospital and long-term outcomes, of enhanced sternal closure with combined band and plate fixation using the new SternaLock^® 360 (SL360) system as an alternative to sternal wiring. From 2020 to 2022, 17 patients underwent enhanced sternal closure using the SL360 at our institution. We analyzed perioperative data, as well as clinical and radiologic follow-up data. The results were as follows: In total, 82% of the patients were treated with the SL360 based on perioperative risk factors, while in 18% of cases, the SL360 was used for secondary closure due to sternal instability. No perioperative complications were observed. We obtained the follow-up data of 82% of the patients (median follow-up time: 141 (47.8 to 511.5) days), showing no surgical revision, no sternal instability, no deep wound infections, and no sternal pain at the follow-up. In one case, a superficial wound infection was treated with antibiotics. In conclusion, enhanced sternal closure with the SL360 is easy to perform, effective, and safe. This system might be considered for both primary and secondary sternal closure in patients at risk of sternal complications.

The Modified Sternoplasty: A Novel Surgical Technique for Treating Mediastinitis

Deep sternal wound infection (DSWI) is one of the most complex and devastating complications post cardiac surgery. We present here the modified sternoplasty, a novel surgical technique for treating DSWI post cardiac surgery. The modified sternoplasty includes debridement and sternal refixation via bilateral longitudinal stainless-steel wires that are placed parasternally along the ribs at the midclavicular or anterior axillary line, followed by six to eight horizontal stainless-steel wires that are anchored laterally and directly into the ribs. On top of that solid structure, wound reconstruction is performed by the use of bilateral pectoralis muscle flaps followed by subcutaneous tissue and skin closure. We reported mortality rates and length of hospitalization of patients who underwent the modified sternoplasty. In total, 68 patients underwent the modified sternoplasty. Two of these critically ill patients died (2.9%). The average length of hospitalization from the diagnosis of DSWI was 24.63 ± 22.09 days. The modified sternoplasty for treating DSWI is a more complex surgery compared with other conventional sternoplasty techniques. However, this technique was demonstrated to be more effective, having a lower rate of mortality, and having a length of hospitalization lower than or comparable to other techniques previously reported in the literature.

Does routine topical antimicrobial administration prevent sternal wound infection after cardiac surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'Does routine topical antimicrobial administration prevent sternal wound infection (SWI) after cardiac surgery? Altogether >238 papers were found using the reported search, of which 11 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Several different antimicrobial agents, dosages and application protocols were found in the literature. Regarding topical vancomycin use, a meta-analysis by Kowalewski et al. demonstrated a 76% risk reduction in any SWI. Collagen-gentamicin sponge application was associated with a 38% risk reduction in SWI in another meta-analysis by Kowalewski et al., which included 4 randomized control trials and >23 000 patients. Lower evidence observational studies found benefit in the use of different regimes, including: combination of vancomycin paste and subcutaneous gentamycin; combined cefazoline and gentamicin spray; isolated cefazolin; bacitracin ointment; and rifampicin irrigation. We conclude that, in light of the body of evidence available, topical antibiotic application prevents SWI, including both superficial and deep SWI. The strongest evidence, derived from 2 meta-analyses, is related to the use of gentamicin-collagen sponges and topical vancomycin. Heterogeneity throughout studies regarding antibiotic agents, dosages, application protocols and SWI definition makes providing general recommendations challenging.

Local prolonged release of antibiotic for prevention of sternal wound infections postcardiac surgery-A novel technology

INTRODUCTION

Sternal wound infection (SWI) is a devastating postcardiac surgical complication. D-PLEX₁₀₀ (D-PLEX) is a localized prolonged release compound applied as a prophylactic at the completion of surgery to prevent SWI. The D-PLEX technology platform is built as a matrix of alternating layers of polymers and lipids, entrapping an antibiotic (doxycycline). The objective of this study was to assess the safety profile and pharmacokinetics of D-PLEX in reducing SWI rates postcardiac surgery.

METHOD

Eighty-one patients were enrolled in a prospective single-blind randomized controlled multicenter study. Sixty patients were treated with both D-PLEX and standard of care (SOC) and 21 with SOC alone. Both groups were followed 6 months for safety endpoints. SWI was assessed at 90 days.

RESULTS

No SWI-related serious adverse events (SAEs) occurred in either group. The mean plasma C_max in patients treated with D-PLEX was about 10 times lower than the value detected following the oral administration of doxycycline hyclate with an equivalent overall dose, and followed by a very low plasma concentration over the next 30 days. There were no sternal infections in the D-PLEX group (0/60) while there was one patient with a sternal infection in the control group (1/21, 4.8%).

CONCLUSION

D-PLEX was found to be safe for use in cardiac surgery patients. By providing localized prophylactic prolonged release of broad-spectrum antibiotics, D-PLEX has the potential to prevent SWI postcardiac surgery and long-term postoperative hospitalization, reducing high-treatment costs, morbidity, and mortality.

An Extended Duration of the Pre-Operative Hospitalization is Associated with an Increased Risk of Healthcare-Associated Infections after Cardiac Surgery

Nosocomial infections are a common complication in clinical practice with major impact on surgical success and patient outcome. The probability of nosocomial infections is rapidly increasing during hospitalization. Therefore, we investigated the impact of a prolonged pre-operative hospital stay on the development of post-operative infection. Within this prospective observational study, 200 patients scheduled for elective cardiac surgery were enrolled. Patients were followed during hospital admission and screened for the development of nosocomial infection. Logistic regression analysis was used to assess the impact of a prolonged pre-operative hospital stay on the development of infection. A total of 195 patients were suitable for the final analysis. We found a strong and direct association of the duration of pre-operative hospital stay and the number of patients developing infection (+23.5%; p = 0.006). Additionally, the length of patients’ pre-operative hospital stay was independently associated with the development of post-operative nosocomial infection, with an adjusted OR per day of 1.38 (95%CI: 1.02–1.86; p = 0.036). A prolonged pre-operative hospital stay was significantly associated with the development of nosocomial infection after cardiac surgery. Those findings need to be considered in future clinical patient management in order to prevent unnecessary antibiotic use and potential harm to patients.

Toxicity and Safety Study of D-PLEX100 in a Sternal Surgical Defect in New Zealand White Rabbits

Bacterial infections are a common complication after surgical procedures. Therefore, local delivery of antibiotics has been developed, including the use of biodegradable polymers. A newly developed product for prevention of surgical site infections is a polymer-lipid encapsulation matrix loaded with doxycycline, named D-PLEX₁₀₀ (D-PLEX). We evaluated the toxicity and safety of D-PLEX using a sternal surgical defect model in rabbits. D-PLEX was tested with three different concentrations of doxycycline in comparison to sham-operated control after administration into the sternal surgical defect and on the ventral side of the sternum in New Zealand White (NZW) rabbits, following 15 months of exposure. No mortality or abnormal clinical findings were attributed to D-PLEX, and clinical pathology assays were normal. Histological examinations revealed no treatment-related adverse findings in any of the examined tissues, including the osseous and surrounding soft tissues. It has been shown that D-PLEX gradually degraded until complete disappearance after 9 months, and mainly during the first 3 months, in parallel to normal bone formation. In addition, the administration of D-PLEX did not affect sternal bone strength. This study adds to the growing data on preclinical safety studies utilizing biodegradable materials and provides information on the expected normal reaction to biodegradable materials in the sternum of NZW rabbits.