Sternal wound infections following cardiac surgery and their management: a single-centre study from the years 2016-2017

Computed Tomography Scanning for Sternal Wound Infections: A Systematic Review

Background

Sternal wound infection (SWI) has always been a significant risk in patients who undergo sternotomies as part of their cardiac surgical procedures. Computed tomography (CT) imaging is often used to diagnose and assess sternal wound infections. Its purpose includes identifying and locating infection and any sternal dehiscence.

Methods

A systematic literature review across PubMed, Embase, and Ovid was performed according to PRISMA guidelines to identify relevant articles that discussed the utility of CT scanning for SWI, common features identified, patient outcomes and sensitivity/specificity (Figure 1).

Results

25 papers were included. 100% (n=25) of the papers were published in peer-reviewed journals. CT scans in SWIs can be seen as a beneficial aid in diagnosing as well as determining the components of infection. Commonalities were identified such as fluid collection in the mediastinum, free gas, pleural effusions, and sternal dehiscence which point towards the presence of sternal wound infection.

Conclusion

CT scanning is a novel and emerging methodology for imaging in SWI and post-sternotomy complications, hence increased research is required to expand the literature on this area as well as the creation of guidelines and cut-offs or signs for radiology professionals to identify and determine the extent of infection.

Impact of local delivery of allogeneic chondrocytes on the biological response and healing of the sternum bones after sternotomy

Median sternotomy is the surgical method of choice for many procedures where one of the main problems is the long post-operative wound healing process leading to sternal dehiscence and the development of infection. This leads to prolonged hospital stay and increased mortality due to post-operative complications. A promising solution seems to be the use of allogeneic chondrocytes for wound treatment, whose properties in the field of cartilage reconstruction are widely used in medicine, mainly in orthopedics. In the present study, we investigated the effect of local delivery of allogeneic chondrocytes on the biological response and healing of the sternum after sternotomy. We optimized the culture conditions for the isolated chondrocytes, which were then applied to the sternal incision wound. Chondrocytes in the culture were assessed on the basis of the presence of chondrocyte-specific genes: Sox9, Aggrecan and Collagen II. In turn, the histopathological and immunohistochemical evaluation was used to assess the safety of implantation. In our work, we demonstrated the possibility of obtaining a viable culture of chondrocytes, which were successfully introduced into the sternal wound after sternotomy. Importantly, implantation of allogeneic chondrocytes showed no significant side effects. The obtained results open new possibilities for research on the use of allogeneic chondrocytes in the process of accelerating wound healing after median sternotomy.

Intranasal Mupirocin to Reduce Surgical Site Infection Post Cardiac Surgery: A Review of the Literature

Sternal wound infections after cardiac surgery are associated with high rates of morbidity and mortality. One of the known risk factors of sternal wound infection is Staphylococcus aureus colonisation. Intranasal mupirocin decolonisation therapy implemented pre-operatively appears to be an effective preventative measure in reducing sternal wound infections post-cardiac surgery. Therefore, the main aim of this review is to evaluate the current literature regarding the use of intranasal mupirocin before cardiac surgery and its impact on sternal wound infection rates.

Bilateral internal thoracic artery use in two-vessel disease does not increase the perioperative risk-A propensity score matched analysis

Background

Bilateral internal thoracic arteries (BITA) are uncommonly used in the every-day practice due to safety concerns and technical challenges with Y-grafts. We hypothesized that in-situ BITA use during coronary artery by-pass grafting (CABG) for two vessel disease is equally safe to standard strategy with left internal thoracic artery-left anterior descending artery revascularization and venous graft to other target vessels.

Methods

A propensity score matched analysis was used to compare elective on-pump CABG patients who received in-situ BITA (BITA-group), versus left internal thoracic artery graft to the left anterior descending artery plus vein (SITA-group). Primary end points were 30-days all-cause-mortality, major adverse cardiac events and incidents and deep sternal wound infections.

Results

A total of 50 matched pairs (c-statistics 0.769) were selected from patients operated on between January 2015 and April 2020 using BITA (n = 50) and SITA (n = 2170). There were no inter-group differences in demographics and basic clinical characteristics. The total operation time was longer in the BITA-group (4.0 vs 3.6 hours; p = 0.004). The rate of complete revascularization was similar, as was median aortic cross-clamp time, median extracorporeal circulation time, rate of re-explorations for bleeding, deep sternal wound infections or length of stay. One patient died in BITA group, 3 days after surgery, from a non-cardiac cause. After 36 months, the survival rate was 98% for BITA-group and 96% for controls (log-rank, p = 0.577).

Conclusions

In-situ use of BITA during coronary revascularization for two-vessel disease is as safe and effective, as use of single ITA and vein graft. In-situ strategy abolishes allows to avoid the technically demanding composite graft configuration.

Antimicrobial prophylaxis in adult cardiac surgery in the United Kingdom and Republic of Ireland

BACKGROUND

Deep sternal wound infections are a financially costly complication of cardiac surgery with serious implications for patient morbidity and mortality. Prophylactic antimicrobials have been shown to reduce the incidence of infection significantly. In 2018, the European Association for CardioThoracic Surgery (EACTS) provided clear guidance advising that third-generation cephalosporins are the first-line prophylactic antimicrobial of choice for cardiac surgery via median sternotomy as a result of their broad spectrum of activity and association with reduced postoperative mortality. Despite this guidance, it was believed that UK practice differed from this as a consequence of national concerns surrounding cephalosporins use and Clostridioides difficile infection.

METHODS

A survey was developed and distributed to all UK and Republic of Ireland (ROI) cardiac surgery centres in January 2019 to quantify this variation.

RESULTS

Of the 38 centres, 34 responded. Variation existed between the antimicrobial agent used, as well as the dosage, frequency and duration of suggested regimens even among centres using the same antimicrobial agent. The most common antimicrobial prophylaxis prescribed was a combination of flucloxacillin and gentamicin (16, 47%). Followed by cefuroxime (6, 17.6%) and cefuroxime combined with a glycopeptide (4, 11.7%). In patients colonised with methicillin-resistant Staphylococcus aureus or those with penicillin allergy gentamicin combined with teicoplanin was most common (42% and 50%, respectively).

DISCUSSION

This variation in antimicrobial agents and regimens may well contribute to the varying incidence of surgical site infection seen across the UK and ROI.