Improved early risk stratification of deep sternal wound infection risk after coronary artery bypass grafting

BACKGROUND

Deep sternal wound infection (DSWI) following open heart surgery is associated with excessive morbidity and mortality. Contemporary DSWI risk prediction models aim at identifying high-risk patients with varying complexity and performance characteristics. We aimed to optimize the DSWI risk factor set and to identify additional risk factors for early postoperative detection of patients prone to DSWI.

METHODS

Single-centre retrospective analysis of patients with isolated multivessel coronary artery disease undergoing myocardial revascularization at Paracelsus Medical University Nuremberg between 2007 and 2022 was performed to identify risk factors for DSWI. Three data sets were created to examine preoperative, intraoperative, and early postoperative parameters, constituting the "Baseline", the "Improved Baseline" and the "Extended" models. The "Extended" data set included risk factors that had not been analysed before. Univariable and stepwise forward multiple logistic regression analyses were performed for each respective set of variables.

RESULTS

From 5221 patients, 179 (3.4%) developed DSWI. The "Extended" model performed best, with the area under the curve (AUC) of 0.80, 95%-CI: [0.76, 0.83]. Pleural effusion requiring intervention, postoperative delirium, preoperative hospital stay > 24 h, and the use of fibrin sealant were new independent predictors of DSWI in addition to age, Diabetes Mellitus on insulin, Body Mass Index, peripheral artery disease, mediastinal re-exploration, bilateral internal mammary harvesting, acute kidney injury and blood transfusions.

CONCLUSIONS

The "Extended" regression model with the short-term postoperative complications significantly improved DSWI risk discrimination after surgical revascularization. Short preoperative stay, prevention of postoperative delirium, protocols reducing the need for evacuation of effusion and restrictive use of fibrin sealant for sternal closure facilitate DSWI reduction.

TRIAL REGISTRATION

The registered retrospective study was registered at the study centre and approved by the Institutional Review Board of Paracelsus Medical University Nuremberg (IRB-2019-005).

Association between HbA1c and deep sternal wound infection after coronary artery bypass: a systematic review and meta-analysis

BACKGROUND

Deep sternal wound infection (DSWI) constitutes a serious complication after coronary artery bypass grafting (CABG) surgery. The aim of this study is to evaluate the dose-response relationship between glycated hemoglobin (HbA1c) level and the risk of DSWI after CABG.

METHODS

PubMed, Scopus, and Cochrane Library databases were searched to identify potentially relevant articles. According to rigorous inclusion and exclusion criteria, fourteen studies including 15,570 patients were enrolled in our meta-analysis. Odds ratio (OR) with 95% confidence intervals (CIs) was used as the summary statistic. The robust-error meta-regression model was used to synthesize the dose-response relationship.

RESULTS

Our meta-analysis shows that among patients undergoing CABG, preoperative elevated HbA1c was associated with the risk of developing DSWI (OR = 2.67, 95% CI 2.00-3.58) but with low prognostic accuracy (diagnostic OR = 2.70, 95% CI 1.96-3.73; area under the curve = 0.66, 95% CI 0.62-0.70) for predicting postoperative DSWI. Subgroup analyses showed the relationship became nonsignificant in patients without diabetes and studies adopting lower HbA1c thresholds. Dose-response analysis showed a significant nonlinear (p = 0.03) relationship between HbA1c and DSWI, with a significantly increased risk of DSWI when HbA1c was > 5.7%.

CONCLUSIONS

An elevated HbA1c level of > 5.7% was related to a higher risk of developing DSWI after CABG, and the risk increased as the HbA1c level grew. The association between HbA1c and DSWI was nonsignificant among nondiabetic patients while significant among diabetic patients.

The impact of two radical sternectomy surgical techniques on the outcome of deep sternal wound infections

BACKGROUND

Deep sternal wound infection (DSWI) is a rare, yet devastating complication after cardiac surgery. While the surgical treatment always implies the soft tissue and bone debridement, there is little data about this procedure. The aim of our study was to evaluate the impact of the radical sternectomy on the outcome in patients with DSWI and to identify the risk factors which could influence the result. The surgical techniques of piecemeal sternectomy and the newly developed en bloc sternectomy were also evaluated.

METHODS

The study was developed as a retrospective cohort study. 86 patients with DSWI who received a radical sternal resection at our institution between March 2018 and December 2021 were included.

RESULTS

The average age of the cohort was 67.3 ± 7.4 years, and 23.3% of patients were female. The average length of stay trended shorter after en bloc sternectomy (median 26 days) compared to piecemeal sternectomy (37 days). There were no significant differences between the piecemeal and en bloc sternal resection techniques. Anticoagulant and antiplatelet drugs had no significant influence on bleeding and transfusion rates. Obese patients showed an increased risk for postoperative bleeding requiring reintervention. Transfusion of packed red blood cells was significantly associated with lower hemoglobin values before surgery and ASA Class 4 compared to ASA Class 3. The in-hospital mortality was 9.3%, with female sex and reintervention for bleeding as significant risk factors. Nine patients developed an infection relapse as a chronic fistula at the level of clavicula or ribs, with ASA Class 4 as a risk factor.

CONCLUSION

Radical sternectomy is a safe procedure to treat DSWI with compromised sternal bone. Both piecemeal and en bloc techniques ensure reliable results, while complications and mortality appear to be patient-related.

Temporal Cluster Analysis of Deep Sternal Wound Infection in a Regional Quality Collaborative

INTRODUCTION

Deep sternal wound infection (DSWI) is a rare complication associated with high mortality. Seasonal variability in surgical site infections has been demonstrated, however, these patterns have not been applied to DSWI. The purpose of this study was to assess temporal clustering of DSWIs.

METHODS

All cardiac surgery patients who underwent sternotomy were queried from a regional Society of Thoracic Surgeons database from 17 centers from 2001 to 2019. All patients with the diagnosis of DSWI were then identified. Cluster analysis was performed at varying time intervals (monthly, quarterly, and yearly) at the hospital and regional level. DSWI rates were calculated by year and month, and compared using mixed-effects negative binomial regression.

RESULTS

A total of 134,959 patients underwent a sternotomy for cardiac surgery, of whom 469 (0.35%) developed a DSWI. Rates of DSWI per hospital across all years ranged from 0.12% to 0.69%. Collaborative-level rates of DSWIs were the greatest in September (0.44%) and the lowest in January (0.30%). Temporal clustering was not seen across seasonal quarters (high rate in preceeding quarter was not associated with a high rate in the next quarter) (P = 0.39). There were yearly differences across all institutions in the DSWI rates. A downward trend in DSWI rates was seen from 2001 to 2019 (P < 0.001). A difference among hospitals in the cohort was observed (P < 0.001).

CONCLUSIONS

DSWI are a rare event within our region. Unlike other surgical site infection, there does not appear to be a seasonal pattern associated with DSWI.

Factors associated with deep sternal wound infection after open-heart surgery in a Danish registry

Objective

To conduct a comprehensive multivariate analysis of variables associated with deep sternal wound infection, after open-heart surgery via median sternotomy.

Method

A retrospective cohort of all adult patients, who underwent open-heart surgery at Odense University Hospital between 01-01-2000 and 31-12-2020 was extracted from the West Danish Heart Registry. Data were analyzed using maximum likelihood logistic regression.

Results

A total of 15,424 patients underwent open-heart surgery and 244 developed a deep sternal wound infection, equivalent to 1,58 %. After data review 11,182 entries were included in the final analysis, of which 189 developed DSWI, equivalent to 1,69 %. Multivariate analysis found the following variables to be associated with the development of deep sternal wound infection (odds ratios and 95%confidens intervals in parentheses): Known arrhythmia (1.70; 1.16-2.44), Left Ventricular Ejection Fraction (1.66; 1.02-2.58), Body Mass Index 25-30 (1.66; 1.12-2.52), Body Mass Index 30-35 (2.35; 1.50-3.71), Body Mass Index 35-40 (3.61; 2.01-6.33), Body Mass Index 40+ (3.70; 1.03-10.20), Age 60-69 (1.64; 1.04-2.67), Age 70-79 (1.95; 1.23-3.19), Chronic Obstructive Pulmonary Disease (1.77; 1.21-2.54), Reoperation (1.63; 1.06-2.45), Blood transfusion in surgery (1.09; 1.01-1.17), Blood transfusion in intensive care unit (1.03; 1.01-1.06), Known peripheral atherosclerosis (1.82; 1.25-2.61), Current smoking (1.69; 1.20-2.35), Duration of intubation (1.33; 1.12-1.57).

Conclusion

Increased risk of deep sternal wound infection after open-heart surgery is a multifactorial problem, while some variables are unchangeable others are not. Focus should be on optimizing the condition of the patient prior to surgery e.g. weight loss and smoking. But also factors surrounding the patient e.g. preventing blood loss and minimizing intubation time.

Microbiological study of sternal osteomyelitis after median thoracotomy - a retrospective cohort study

INTRODUCTION

Deep sternal wound infection is a rare but feared complication of median thoracotomies and is usually caused by microorganisms from the patient's skin or mucous membranes, the external environment, or iatrogenic procedures. The most common involved pathogens are Staphylococcus aureus, Staphylococcus epidermidis and gram-negative bacteria. We aimed to evaluate the microbiological spectrum of deep sternal wound infections in our institution and to establish diagnostic and treatment algorithms.

METHODS

We retrospectively evaluated the patients with deep sternal wound infections at our institution between March 2018 and December 2021. The inclusion criteria were the presence of deep sternal wound infection and complete sternal osteomyelitis. Eighty-seven patients could be included in the study. All patients received a radical sternectomy, with complete microbiological and histopathological analysis.

RESULTS

In 20 patients (23%) the infection was caused by S. epidermidis, in 17 patients (19.54%) by S. aureus, in 3 patients (3.45%) by Enterococcus spp., in 14 patients (16.09%) by gram-negative bacteria, while in 14 patients (16.09%) no pathogen could be identified. In 19 patients (21,84%) the infection was polymicrobial. Two patients had a superimposed Candida spp.

INFECTION

Methicillin-resistant S. epidermidis was found in 25 cases (28,74%), while methicillin-resistant S. aureus was isolated in only three cases (3,45%). The average hospital stay for monomicrobial infections was 29.93 ± 13.69 days and for polymicrobial infections was 37.47 ± 19.18 (p = 0.03). Wound swabs and tissue biopsies were routinely harvested for microbiological examination. The increasing number of biopsies was associated with the isolation of a pathogen (4.24 ± 2.22 vs. 2.18 ± 1.6, p < 0,001). Likewise, the increasing number of wound swabs was also associated with the isolation of a pathogen (4.22 ± 3.34 vs. 2.40 ± 1.45, p = 0.011). The median duration of antibiotic treatment was 24.62 (4-90) days intravenous and 23.54 (4-70) days orally. The length of antibiotic treatment for monomicrobial infections was 22.68 ± 14.27 days intravenous and 44.75 ± 25.87 days in total and for polymicrobial infections was 31.65 ± 22.29 days intravenous (p = 0.05) and 61.29 ± 41.45 in total (p = 0.07). The antibiotic treatment duration in patients with methicillin-resistant Staphylococci as well as in patients who developed an infection relapse was not significantly longer.

CONCLUSION

S. epidermidis and S. aureus remain the main pathogen in deep sternal wound infections. The number of wound swabs and tissue biopsies correlates with accurate pathogen isolation. With radical surgical treatment, the role of prolonged antibiotic treatment remains unclear and should be evaluated in future prospective randomized studies.

Pathological study of sternal osteomyelitis after median thoracotomy-a prospective cohort study

PURPOSE

Osteomyelitis of the sternum may arise either as a primary condition or secondary to median thoracotomy after cardiac surgery, with the latter being decidedly more frequent. Deep sternal wound infections appear as a complication of median thoracotomy in 0.2 to 4.4% of cases and may encompass the infection of the sternal bone. To date, there are no exhaustive histopathological studies of the sternal osteomyelitis.

METHODS

Our work group developed a surgical technique to remove the complete infected sternal bone in deep sternal wound infections. We therefore prospectively examined the en bloc resected sternal specimens. Seven standard histological sections were made from the two hemisternums.

RESULTS

Forty-seven sternums could be investigated. The median age of the patients in the cohort was 66 (45-81) years and there were 10 females and 37 males. Two methods were developed to examine the histological findings, with one model dividing the results in inflammatory and non-inflammatory, while the second method using a score from 0 to 5 to describe more precisely the intensity of the bone inflammation. The results showed the presence of inflammation in 76.6 to 93.6% of the specimens, depending on the section. The left manubrial sections were more prone to inflammation, especially when the left mammary artery was harvested. No further risk factors proved to have a statistical significance.

CONCLUSION

Our study proved that the deep sternal wound infection may cause a ubiquitous inflammation of the sternal bone. The harvest of the left mammary artery may worsen the extent and intensity of infection.

Off-Pump Bilateral Skeletonized Internal Thoracic Artery Grafting in Octogenarians

BACKGROUND

We compared postoperative outcomes in octogenarians who underwent off-pump isolated coronary artery bypass grafting for multivessel disease using either skeletonized bilateral or single internal thoracic artery (ITA).Methods and Results: Among 1,532 patients who underwent isolated coronary artery bypass grafting between 2002 and 2021, 173 octogenarians were analyzed retrospectively. After inverse probability of treatment weighting, we found no statistically significant difference regarding patients' preoperative characteristics. No patient experienced deep sternal wound infection. More patients in the single than bilateral ITA group died within 30 days after surgery (5.0% vs. 0%, respectively; P=0.003). The mean follow-up duration was 4.2 years. At 5 years, the freedom from overall death following bilateral versus single ITA grafting was 78.2% and 53.7%, respectively (log-rank test, P=0.003), and freedom from major adverse cardiac and cerebrovascular events (MACCE) was 67.9% and 44.8% respectively (log-rank test, P=0.002). In multivariable Cox models, bilateral ITA grafting was significantly associated with a lower risk of overall death (hazard ratio [HR] 0.555; 95% confidence interval [CI] 0.342-0.903; P=0.018) and MACCE (HR 0.586; 95% CI 0.376-0.913; P=0.018).

CONCLUSIONS

Compared with single ITA grafting, off-pump skeletonized bilateral ITA grafting is associated with lower rates of overall death and MACCE in octogenarians undergoing CABG and does not increase the risk of deep sternal wound infection.

Reconstruction of Infected Mediastinal Wound with an Omental Flap Harvested Laparoscopically After Cardiac Surgery: Report of Two Cases and Literature Review

Background

Deep sternal wound infection and dehiscence are two serious complications after open cardiac surgery. Omental flap harvesting is recognized as one of the management options, with traditionally non-favorable outcomes due to laparotomy stress on patients.

Objective

Herein, however, we report our experience with two patients who have developed a mediastinal wound infection following coronary artery bypass grafting and were reconstructed with omental flaps harvested laparoscopically.

Case Presentation

Two 74-year-old females, who were known to have multiple comorbidities, developed a sternal wound infection after coronary artery bypass graft. Several operative trials and non-operative measures have been attempted to manage the infections and/or reconstruct the wound but failed. Both patients then underwent laparoscopic omental flap harvesting for reconstruction and exhibited significant clinical improvement postoperatively.

Discussion

Omental flap is considered a feasible option for reconstruction of sternal wound dehiscence developing after open cardiac surgery because it is usually well-vascularized, contains a large number of immunologically active cells and has the ability to absorb wound secretions. The traditional method of harvesting is conventional laparotomy, but it carries high rates of morbidity. Therefore, laparoscopic harvesting can be utilized as an alternative with better outcomes.

Conclusion

Laparoscopic omental flap harvesting is considered a feasible and safe procedure to manage sternal wound dehiscence after open cardiac surgery, with satisfactory surgical outcomes.

Bilateral internal thoracic artery coronary grafting: risks and benefits in elderly patients

AIMS

Whether bilateral internal thoracic artery (BITA) grafting benefits elderly patients in coronary artery bypass grafting (CABG) remains unclear since they tend to have a limited life expectancy and severe comorbidities. We aim to evaluate the outcomes of BITA vs. single internal thoracic artery (SITA) grafting in elderly patients.

METHODS AND RESULTS

A meta-analysis was performed by database searching until May 2021. Studies comparing BITA and SITA grafting among elderly patients were included. One randomized controlled trial, nine propensity score matching, and six unmatched studies were identified, with a total of 18 146 patients (7422 received BITA grafting and 10 724 received SITA grafting). Compared with SITA grafting, BITA grafting had a higher risk of deep sternal wound infection (DSWI) [odds ratio: 1.67; 95% confidence interval (CI): 1.22-2.28], and this risk could not be significantly reduced by the skeletonization technique. Meanwhile, BITA grafting was associated with a higher long-term survival [hazard ratio: 0.83; 95% CI: 0.77-0.90], except for the octogenarian subgroup. Reconstructed Kaplan-Meier survival curves revealed 4-year, 8-year, and 12-year overall survival rates of 85.5%, 66.7%, and 45.3%, respectively, in the BITA group and 79.3%, 58.6%, and 34.9%, respectively, in the SITA group. No significant difference was observed in early mortality, perioperative myocardial infarction, perioperative cerebral vascular accidents, or re-exploration for bleeding.

CONCLUSION

Compared with SITA grafting, BITA grafting could provide a long-term survival benefit for elderly patients, although this benefit remained uncertain in octogenarians. Meanwhile, elderly patients who received BITA were associated with a higher risk of DSWI and such a risk could not be eliminated by the skeletonization technique.

The combined application of antibiotic-loaded bone cement and vacuum sealing drainage for sternal reconstruction in the treatment of deep sternal wound infection

Background

Deep sternal wound infection (DSWI) is a rare but serious complication after median sternotomy, and treatment success depends mainly on surgical experience. Traditional treatment methods for DSWI include complete debridement, vacuum sealing drainage wound therapy and sometimes transposition of muscle flap. This study aimed to evaluate the utility of antibiotic-loaded bone cement combined with vacuum sealing drainage on DSWI and explore the effect of this treatment on lung function.

Methods

Between January 2018 and December 2019, we treated 12 patients suffering a mediastinitis and open thorax using antibiotic-loaded bone cement combined with vacuum sealing drainage. Subsequently, the blood and local concentration of antibiotic were measured. The patient characteristics, pulmonary function, were retrospectively analyzed. Subjects were followed up for 12 months.

Results

There were no intraoperative deaths. All patients’ healing wounds were first-stage healing without complications and reoperation, the mean hospital stay was 20.2 ± 3.5 days. Local vancomycin concentrations largely exceeded the ones needed for their efficacy while little antibiotic was found in the blood. Pulmonary function testing was improved 2 weeks after the operation. No infection reoccurred in12-month follow-up.

Conclusions

The antibiotic-loaded bone cement combined with vacuum sealing drainage might be an effective method for the sternal reconstruction of deep sternal wound infection and it can improve the patient's lung function in a short time.

Incidence and outcomes of surgical site infection after cardiovascular surgery (complete republication)

OBJECTIVES

Surgical site infection in cardiovascular surgery had a great effect on postoperative outcomes. This study examined the current status of surgical site infection and postoperative outcomes used the registered data of the Japan Cardiovascular Surgery Database.

METHODS

From the registry, we extracted 53,186 cases of thoracic cardiovascular surgery performed under median sternotomy in 2018. According to Japanese Healthcare Associated Infections Surveillance (JHAIS), patients were divided into three groups: coronary artery bypass graft (CABG) with saphenous vein graft (SVG) (SVG+ ; n = 14,246), CABG without SVG (SVG-; n = 5535), and operations other than CABG (no CABG; n = 33,405). The incidence of deep sternal wound infection, leg wound infection, hospital death, and hospitalization more than 90 days was examined.

RESULTS

The incidence of deep sternal wound infection is 1.4% in all cases and 1.7% in SVG+ , 1.2% in SVG-, and 1.4% in no CABG. In deep sternal wound infection cases, incidence of hospital death was 24.7% and was higher than no infection cases. Especially, in no CABG group, incidence of hospital death was 30.1%. The long-term hospitalization rate and readmission rate within 30 days of patients with deep sternal wound infection were also high.

CONCLUSIONS

The incidence of deep sternal wound infection was low, but it has not decreased. Postoperative outcomes in patients with surgical site infection were still bad.

Application of local gentamicin in the treatment of deep sternal wound infection: a randomized controlled trial

OBJECTIVES

In patients with deep sternal wound infection (DSWI), primary closure of the sternal bone over high negative pressure Redon drains has shown to be a safe and feasible treatment method. Addition of local gentamicin could accelerate healing and improve clinical outcomes.

METHODS

We conducted a randomized controlled trial to evaluate the effectiveness of local gentamicin in the treatment of DSWI. In the treatment group, collagenous carriers containing gentamicin were left between the sternal halves during sternal refixation. In the control group, no local antibiotics were used. Primary outcome was hospital stay. Secondary outcomes were mortality, reoperation, wound sterilization time, time till removal of all drains and duration of intravenous antibiotic treatment.

RESULTS

Forty-one patients were included in the trial of which 20 were allocated to the treatment group. Baseline characteristics were similar in both groups. Drains could be removed after a median of 8.5 days in the treatment group and 14.5 days in the control group (P-value: 0.343). Intravenous antibiotics were administered for a median of 23.5 days in the treatment group and 38.5 days in the control group (P-value: 0.343). The median hospital stay was 27 days in the treatment group and 28 days in the control group (P-value: 0.873). Mortality rate was 10% in the treatment group and 9.5% in the control group (P-value: 0,959). No side effects were observed.

CONCLUSIONS

This randomized controlled trial showed that addition of local gentamicin in the treatment of DSWI did not result in shorter length of stay.

CLINICAL TRIAL REGISTRATION NUMBER

2014-001170-33.

Using antibiotic-loaded bone cement for a patient with deep sternal wound infection after cardiac surgery

A 67-year-old male presented with sternal dehiscence following open cardiac surgery. Extensive debridement and attempted closure failed, and the wound had since been managed with vacuum-assisted closure therapy, with little progress. We treated him with antibiotic-loaded bone cement to repair the wound defect. After 3 weeks, the wound healed with excellent result. To our knowledge, this is the first report of antibiotic-loaded bone cement for deep sternal wound infection.

Characteristics and outcomes of patients with postoperative Candida versus bacterial mediastinitis: a case-matched comparative study

OBJECTIVES

Postoperative mediastinitis, a feared complication after cardiac surgery, is associated with high mortality, especially of critically ill patients. Candida species infections are rare and severe, with poorly known outcomes. We conducted a case-control study to describe the characteristics, management and outcomes of patients with postoperative Candida mediastinitis.

METHODS

This French, monocentre, retrospective study included all patients with postoperative Candida mediastinitis (January 2003-February 2020) requiring intensive care unit admission. Candida mediastinitis patients (henceforth cases) were matched 1:1 with postoperative bacterial mediastinitis (henceforth control), based on 3 factors during mediastinitis management: age >40 years, cardiac transplantation and invasive circulatory device used. The primary end point was the probability of survival within 1 year after intensive care unit (ICU) admission.

RESULTS

Forty cases were matched to 40 controls. The global male/female ratio was 2.1, with mean age at admission 47.9 ± 13.8 years. Candida species were: 67.5% albicans, 17.5% glabrata, 15% parapsilosis, 5.0% tropicalis, 2.5% krusei and 2.5% lusitaniae. The median duration of mechanical ventilation was 23, 68.8% of patients received renal replacement therapy and 62.5% extracorporeal membrane oxygenation support. The probability of survival within the first year after ICU admission was 40 ± 5.5% and was significantly lower for cases than for controls (43 ± 8% vs 80 ± 6.3%, respectively; Log-rank test: P < 0.0001). The multivariable Cox proportional hazards model retained only renal replacement therapy [hazard ratio (HR) 3.7, 95% confidence interval (CI) 1.1-13.1; P = 0.04] and Candida mediastinitis (HR 2.4, 95% CI 1.1-5.6; P = 0.04) as independently associated with 1-year mortality.

CONCLUSIONS

Candida mediastinitis is a serious event after cardiac surgery and independently associated with 1-year mortality. Further studies are needed to determine whether deaths are directly attributable to Candida mediastinitis.

Antibiotic-loaded bone cement combined with vacuum sealing drainage to treat deep sternal wound infection following cardiac surgery: the first case report

Background

Deep sternal wound infection (DSWI) is a rare but serious complication after median sternotomy, and treatment success depends mainly on surgical experience. Here we first present a case of a patient successfully treated for antibiotic-loaded bone cement (ALBC) combined with vacuum sealing drainage (VSD) of DSWI.

Case presentation

This case report presented a patient who underwent open heart surgery, and suffered postoperatively from a DSWI associated with enterococcus cloacae. Focus debridement combined with ALBC filling and VSD was conducted in stage I. Appropriate antibiotics were started according to sensitivity to be continued for 2 weeks until the inflammatory markers decreased to normal. One month after the surgery, patient’s wound was almost healed and was discharged from hospital with a drainage tube. Two months after the stage I surgery procedure, the major step was removing the previous ALBC, and extensive debridement in stage II. The patient fully recovered without further surgical treatment.

Conclusions

The results of this case suggest that ALBC combined with VSD may be a viable and safe option for deep sternal wound reconstruction.

Systematic literature review evaluating evidence and mechanisms of action for platelet-rich plasma as an antibacterial agent

Platelet rich plasma or PRP is a supraphysiologic concentrate of platelets derived by centrifugation and separation of whole blood components. Along with platelets and plasma, PRP contains various cell types including white blood cells (WBC)/leukocytes, both granulocytes (neutrophils, basophils, eosinophils) and agranulocytes (monocytes, lymphocytes). Researchers and clinicians have explored the application of PRP in wound healing and prevention of surgical wound infections, such as deep sternal wounds. We conducted this systematic literature review to evaluate the preclinical and clinical evidence for the antibacterial effect of PRP and its potential mechanism of action. 526 records were identified for screening. 34 unique articles were identified to be included in this literature review for data summary. Overall, the quality of the clinical trials in this review is low, and collectively qualify as Oxford level C. Based on the available clinical data, there is a clear trend towards safety of autologous PRP and potential efficacy in deep sternal wound management. The preclinical and bench data is very compelling. The application of PRP in treatment of wounds or prevention of infection with PRP is promising but there is a need for foundational bench and preclinical animal research to optimize PRP as an antibacterial agent, and to provide data to aid in the design and conduct of well-designed RCTs with adequate power to confirm antimicrobial efficacy of PRP in specific disease states and wound types.

Short- and long-term mortality after deep sternal wound infection following cardiac surgery: experiences from SWEDEHEART

OBJECTIVES

Deep sternal wound infection (DSWI) is a serious complication after open-heart surgery. We investigated the association between DSWI and short- and long-term all-cause mortality in a large well-defined nationwide population.

METHODS

A retrospective, nationwide cohort study, which included 114676 consecutive patients who underwent coronary artery bypass grafting (CABG) and/or valve surgery from 1997 to 2015 in Sweden. Short- and long-term mortality was compared between DSWI patients and non-DSWI patients using propensity score inverse probability weighting adjustment based on patient characteristics and comorbidities. Median follow-up was 8.0 years (range 0-18.9).

RESULTS

Altogether, 1516 patients (1.3%) developed DSWI, most commonly in patients undergoing combined CABG and valve surgery (2.1%). DSWI patients were older and had more disease burden than non-DSWI patients. The unadjusted cumulative mortality was higher in the DSWI group compared with the non-DSWI group at 90 days (7.9% vs 3.0%, P < 0.001) and at 1 year (12.8% vs 4.5%, P < 0.001). The adjusted absolute difference in risk of death was 2.3% [95% confidence interval (CI): 0.8-3.9] at 90 days and 4.7% (95% CI: 2.6-6.7) at 1 year. DSWI was independently associated with 90-day [adjusted relative risk (aRR) 1.89 (95% CI: 1.38-2.59)], 1-year [aRR 2.13 (95% CI: 1.68-2.71)] and long-term all-cause mortality [adjusted hazard ratio 1.56 (95% CI: 1.30-1.88)].

CONCLUSIONS

Both short- and long-term mortality risks are higher in DSWI patients compared to non-DSWI patients. These results stress the importance of preventing these infections and careful postoperative monitoring of DSWI patients.

Bilateral Internal Thoracic Artery Grafting in Hemodialysis Patients

BACKGROUND

We compared postoperative outcomes in hemodialysis (HD) patients who underwent isolated coronary artery bypass grafting (CABG) for multivessel disease using either bilateral or single skeletonized internal thoracic artery.Methods and Results:Among 1,486 patients who underwent isolated CABG between 2002 and 2020, 145 HD patients were retrospectively analyzed. After inverse probability of treatment weighting, there were no significant differences in the preoperative characteristics. No significant differences in 30-day mortality (P=0.551) or postoperative deep sternal wound infection (P=0.778) were observed. However, the bilateral internal thoracic artery grafting group had a lower postoperative stroke rate (0% vs. 4.0%, P=0.019). No significant differences in freedom from all-cause death (P=0.760) and cardiac death (P=0.863) were found. In the multivariate Cox proportional hazards models, bilateral internal thoracic artery grafting was not associated with all-cause death (P=0.246) or cardiac death (P=0.435).

CONCLUSIONS

Bilateral internal thoracic artery grafting in HD patients did not improve mid-term outcomes, but it was also not associated with worse postoperative outcomes. Use of the bilateral internal thoracic artery may be an important option in patients with limited conduits to prevent postoperative complications.

Acute mediastinitis, mediastinal granuloma, and chronic fibrosing mediastinitis: A review

Acute mediastinitis is a rare infection that carries high morbidity and mortality. They are complications seen most often with deep sternal wound infections from surgeries with median sternotomies, oropharyngeal and odontogenic infections and esophageal perforations. These conditions should be promptly recognized and treated. Mediastinal granulomas are focal, mass-like lesions commonly resulting from prior granulomatous infections. They are regarded as benign, self-resolving lesions however can cause complications by compression of adjacent mediastinal structures. Chronic fibrosing mediastinitis is a rare, diffuse fibroinflammatory process most often seen with granulomatous infections and carries a worse prognosis than mediastinal granulomas especially when adjacent mediastinal structures are compromised. In this review, we discuss the epidemiology, etiology, clinical presentation, treatment and prognosis of acute mediastinitis, mediastinal granulomas, and chronic fibrosing mediastinitis.

Antibiotic-loaded ceramic sternum for sternal replacement in a patient with deep sternal wound infection

A 68-year-old man presented with destruction of his sternum after cardiac surgery. Classical management with multiple debridements, vacuum dressings and antibiotics failed. A replacement of his sternum was performed using an antibiotic-loaded porous alumina ceramic sternum. Despite the infected wound, the ceramic sternum did not get infected due to the high antibiotic concentration obtained locally. Two years after the surgery, no relapse occurred and the pulmonary function tests improved.

Impact of microbial findings on plastic reconstructive surgery outcomes in patients with deep sternal wound infection after cardiac surgery

Deep sternal wound infection (DSWI) is a life threatening complication after cardiac surgery. In severe cases, flaps are needed to cover the wound. However, it is controversial if an aseptic environment is necessary at the time of wound closure. This is a retrospective study of 73 patients with DSWI treated by debridement and local or free flap from June 2008 until December 2017. The influence of positive microbiological findings at the time of plastic reconstructive surgery on reoperation rate and length of in-hospital stay was analyzed. Microbiological exams revealed positive results in 47 (64.4%) and no results in 26 patients. Reoperation had to be performed in 21.3% (positive cultures) versus 15.4% (p = .54), mean in hospital stay was 24.1 days (positive cultures) versus 21.8 days (p = .39) and in-hospital mortality was 6.4% (positive cultures) versus 7.7% (p = .83). Positive microbial findings at the time of plastic reconstructive surgery in patients with DSWI are not associated with a higher reoperation or mortality rate or a longer in-hospital stay. Repeated debridement and vacuum-assisted therapy to achieve negative microbial results might not be necessary in the treatment of these patients.Key messagesPositive microbial findings at the time of plastic reconstructive surgery in patients with deep sternal wound infection seems not to be associated with a higher reoperation or mortality rate or a longer in-hospital stay.The influence of positive microbiological findings at the time of plastic reconstructive surgery on reoperation rate and length of in-hospital stay was analyzed in 73 patients with deep sternal wound infection.Microbiological exams revealed positive results in 47 (64.4%) and no results in 26 patients. Reoperation had to be performed in 21.3% (positive cultures) versus 15.4% (p = .54), mean in hospital stay was 24.1 days (positive cultures) versus 21.8 days (p = .39) and in-hospital mortality was 6.4% (positive cultures) versus 7.7% (p = .83).

Efficacy of new multimodal preventive measures for post-operative deep sternal wound infection

BACKGROUND

Deep sternal wound infection (DSWI) is a critical complication of cardiovascular surgery. This study aimed to confirm the efficacy of new, multimodal preventive measures for post-operative DSWI.

METHODS

From January 2008 to December 2012, 1240 patients underwent cardiovascular surgery via median sternotomy at our hospital. The patients were divided into two groups according to the period in which surgery was performed: those treated before and those treated after January 2011, which was when we implemented the new preventive measures against DSWI. The preventive measures included routine use of an off-pump technique in coronary artery bypass grafting, higher body temperature of pump cases, screening and pre-operative eradication of nasal methicillin-resistant Staphylococcus aureus colonization, and use of a microbial sealant. We compared the incidence of DSWI between the two time periods. Univariate and multivariate analyses were also performed for the entire period to identify DSWI risk factors.

RESULTS

Only 1 case (0.2%) of DSWI was noted among 554 patients in the latter period while 25 patients (3.6%) experienced DSWI among the 686 patients in the earlier period (p < 0.0001). The risk factors for DSWI were body mass index (BMI) ≥ 25 kg/m² and operation time ≥ 8 h.

CONCLUSIONS

We observed a marked decrease in the incidence of DSWI after the implementation of multimodal preventive measures. The risk factors for DSWI were BMI ≥ 25 kg/m² and operation time ≥ 8 h.

Post-sternotomy deep wound infection following aortic surgery: wound care strategies to prevent prosthetic graft replacement†

OBJECTIVES

The aim of this study was to evaluate the early and long-term outcomes of our multidisciplinary strategy for treating deep sternal wound infection after aortic grafting, which consisted of debridement by a plastic surgeon, negative pressure wound therapy with continuous irrigation and chest wall reconstruction.

METHODS

We performed a retrospective analysis of 18 patients who had a deep sternal wound infection following aortic grafting through a median sternotomy between January 2009 and December 2017. All patients had organisms cultured from mediastinal tissue within 2 months from the initial aortic surgery. The prosthetic grafts were exposed in 15 patients during resternotomy. Our protocol involved repeat debridement and negative pressure wound therapy with continuous irrigation twice a week until the results of the culture were negative and chest wall reconstruction was complete.

RESULTS

The mean duration from primary aortic surgery to resternotomy was 23.7 ± 15.9 days. Except for 1 patient, 17 patients underwent chest wall reconstruction. The mean duration from resternotomy to chest wall reconstruction was 31.1 ± 28.0 days. The hospital mortality rate was 16.7% (3 patients), although no patients died of wound-related causes. The mean follow-up period was 2.9 ± 2.5 years. Overall survival was 69.6 ± 11.4% at 1 year and 54.2 ± 13.3% at 5 years. Freedom from reoperation for reinfection was 94.4 ± 5.4% at 5 years.

CONCLUSIONS

Our wound care strategy achieved acceptable early and late survival in patients who had deep sternal wound infection following aortic grafting. This strategy may benefit those who experience this devastating complication.

[Wound infections following open heart surgery - review]

Wound infections are common complications after open heart surgery, both in the sternotomy and vein harvest wound. Fortunately, most of these infections are superficial and respond to minor wound debridement and antibiotics, however, 1-3% of patients develop deep sternal wound infection with mediastinis; an infection that can be fatal. Late infections with sternocutaneous fistulas are encountered less often, but also represent a complex surgical problem. The vein harvest site is the most common site for wound infections after cardiac surgery and these infections result in significant patient morbidity and increases health-care costs. This evidence-based review covers etiology, risk factors, prevention and treatment of wound infections following open heart surgery with special focus on advances in treatment, especially negative-pressure wound therapy.

Clinical experience with dalbavancin for the treatment of deep sternal wound infection

OBJECTIVES

Deep sternal wound infection (DSWI) is a complication of major heart surgery with high morbidity as well as prolonged antimicrobial treatment and hospital length of stay (LoS). Dalbavancin is a new lipoglycopeptide antibiotic active against Gram-positive micro-organisms, including methicillin-resistant Staphylococcus aureus (MRSA), with a long half-life. This small case series assessed the feasibility of dalbavancin for the treatment of DSWI.

METHODS

This was retrospective, observational, cohort study of patients treated with dalbavancin for DSWI over a 2-year period (March 2016 to April 2018) in two cardiac surgery departments in Italy. All patients with DSWI underwent surgical accurate debridement. Dalbavancin was administered during the hospital stay or in an outpatient facility.

RESULTS

Among 15 patients enrolled in the study, MRSA was isolated in 7 (47%), methicillin-resistant Staphylococcus epidermidis in 6 (40%) and other coagulase-negative staphylococci in 2 (13%). Dalbavancin was administered by two infusions in 9 patients (60%), whereas 5 patients (33%) received a median of four doses. Fourteen patients received a first dose of 1000mg followed by 500mg, whereas one patient received two doses of 1500mg each. All patients were defined as clinically cured. The median hospital LoS was 13 days (interquartile range, 8-18 days). At 6 months after discharge, 14 patients (93%) showed no relapse of DSWI, whereas 1 patient recurred with a diagnosis of DSWI caused by another pathogen (Candida sp.).

CONCLUSION

Dalbavancin may be an alternative option for DSWI caused by Gram-positive bacteria when first-line treatments are contraindicated or as salvage treatment.

The 'Two Bridges Technique' for sternal wound closure. The use of vacuum-assisted closure for the treatment of deep sternal wound defects: a centre-specific technique

The objective is to describe the 'Two Bridges Technique' (TBT), which has proven to be successful and has been the standard technique at our centre for vacuum-assisted closure (VAC) of post-sternotomy mediastinitis. An extensive literature search was performed in four databases to identify all published articles concerning VAC for post-sternotomy mediastinitis. Several VAC methods have been used; however, no article has described our specific technique. TBT consists of a two-bridges construction using two types of foam with different pore sizes, which ensures an equally divided negative pressure over the wound bed and stabilisation of the chest. This guarantees a continuous treatment of the sternal defect and prevents foam displacement. It maintains an airtight seal that prevents skin maceration and provides enough protection to avoid right ventricular rupture. The main advantage of TBT is the prevention of shifting or tilting of the foam during chest movements such as breathing or couching. Along with targeted antibiotic treatment, this alternative VAC technique can be an asset in the sometimes cumbersome treatment of post-sternotomy mediastinitis.

Scoring system to guide decision making for the use of bilateral internal mammary arteries: The BIMA score

OBJECTIVE

Currently, surgeons are unable to estimate whether the survival benefit from bilateral internal mammary artery (BIMA) grafting outweighs the increased deep sternal infection (DSWI) risk in the individual cases. As a consequence BIMA grafting is still largely underutilized. We aimed to develop and validate a scoring system to predict the individual risk for DSWI and 10 year survival probability to guide surgeons in decision making process for the use of BIMA over single internal mammary artery (SIMA).

METHODS

Fast backward elimination on predictors was performed using Lawless and Singhal method. BIMA score was reported as a partial nomogram that can be used to manually obtain predicted individual risk of DSWI and 10 year survival probability from the regression models. Bootstrapping validation of the regression models was performed.

RESULTS

The study population consisted of 5234 patients of which a total of 960 (18%) received BIMA and the remaining 4274 (82%) underwent conventional strategy using SIMA. A total of 119 patients experienced DSWI (2.3%). A total of 489 deaths were recorded after a median follow-up time of 5.68 years (interquartile range 2.7-8.8, range 0-12.1). BIMA grafting was found to have effect on both risk of DSWI and 10 year survival probability and was included into partial nomograms. Bootstrapping validation confirmed a good discriminative power of the models.

CONCLUSION

The BIMA score provides an impartial assessment of the decision making process for clinicians to establish the optimum revascularization strategy for individual patients.

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

OBJECTIVES

Deep sternal wound infection is still a major complication in patients undergoing cardiac surgery. We previously identified mammary artery harvesting as a risk factor for decreased antibiotic tissue penetration. In addition, other risk factors including diabetes may inhibit sufficient tissue penetration of perioperative antibiotic prophylaxis. A novel closure protocol applying 2 topical antibiotics and further recommendations for sternal wiring was introduced at our department to decrease the incidence of sternal wound infections.

METHODS

A 12-month period prior to (March 2013-February 2014) and after (July 2014-June 2015) the introduction of a novel sternal closure protocol was studied. All sternal wound infections resulting from an operation during this period were analysed. The closure protocol consisted of the intra-sternal application of vancomycin and the subcutaneous application of gentamicin. Furthermore, we increased the number of sternal wires for more uniform distribution of lateral forces.

RESULTS

Patients in both groups were comparable regarding demographic data and risk factors. Fifty-three out of 919 patients operated prior to the protocol change developed an infection (5.8%). The introduction of the novel sternal closure protocol reduced this number to 19 out of 932 patients (2.0%; P  < 0.001). A binary regression including common risk factors revealed a strong independent risk reduction by the novel protocol (OR 0.322, P  < 0.001). The number of sternal wires was not significant in this analysis.

CONCLUSIONS

The topical application of 2 antibiotic agents significantly reduced sternal wound infection. However, the results of this trial should be confirmed in a randomized trial.

Preliminary result with incisional negative pressure wound therapy and pectoralis major muscle flap for median sternotomy wound infection in a high-risk patient population

Deep sternal wound infection (DSWI) represents a dangerous complication that can follow open-heart surgery with median sternotomy access. Muscle flaps, such as monolateral pectoralis major muscle flap (MPMF), represent the main choices for sternal wound coverage and infection control. Negative pressure incision management system has proven to be able to reduce the incidence of these wounds' complications. Prevena™ represents one of these incision management systems and we aimed to evaluate its benefits. A total of 78 patients with major risk factors that presented post-sternotomy DSWI following cardiac surgery was selected. Thrity patients were treated with MPMF and Prevena™ (study group). Control group consisted of 48 patients treated with MPMF and conventional wound dressings. During the follow-up period, 4 (13%) adverse events occurred in the study group, whereas 18 complications occurred (37·5%) in the control group. Surgical revision necessity and mean postoperative time spent in the intensive care unit were both higher in the control group. Our results evidenced Prevena™ system's ability in improving the outcome of DSWI surgical treatment with MPMF in a high-risk patient population.

Bilateral internal thoracic artery grafting in India-Time to raise the bar

Objectives

Bilateral internal thoracic artery (BITA) grafting strategy is the current trend in coronary artery bypass grafting for multivessel coronary artery disease. Although better long-term outcomes have been shown, BITA grafting is underutilized as a main strategy for revascularization by most of the surgeons. The survey was conducted to ascertain the current usage and concerns of BITA grafting in India.

Methods

Database of 856 Indian cardiac surgeons currently with predominantly adult practice was prepared and a questionnaire was sent about use of single and bilateral ITA grafts and BITA grafting strategy in different clinical scenarios.

Results

A total of 112 surgeons (13.08%) from 75 institutions responded and 92 surgeons (10.7%) completed the survey. Single ITA is used by 79% of surgeons in more than 90% of their patients. 31% and 29% of surgeons use BITA grafting in 5–10% and 11–98% of their patients respectively. 53% of surgeons avoided the usage of BITA grafting in patients with smoking, 35% of surgeons in chronic obstructive pulmonary disease, 58% of surgeons in obesity and 62% of surgeons in acute coronary syndrome, 36% of surgeons in patients with left ventricular dysfunction and 61% of surgeons in patients with poor coronary anatomy. The concerns for BITA usage are risk of deep sternal wound infection (DSWI) (40%), increased operative time (27%), unknown superiority (12%) and limited length of right ITA (5%).

Conclusions

The usage of BITA grafting is restricted to 10% in India and main concerns are DSWI and increased operative time.

Effect of negative pressure wound therapy followed by tissue flaps for deep sternal wound infection after cardiovascular surgery: propensity score matching analysis

OBJECTIVES

Deep sternal wound infection (DSWI) after cardiovascular surgery via median sternotomy remains a severe complication associated with a drastic decrease in the quality of life. We assessed the risk factors for in-hospital death caused by DSWI and the available treatments for DSWI.

METHODS

Between January 1991 and August 2015, we retrospectively reviewed 73 patients (51 males and 22 females, mean age 67.5 ± 10.3 years) who developed DSWI after cardiovascular surgery via median sternotomy. Pathogenic bacteria mainly comprised methicillin-resistant Staphylococcus aureus (MRSA) (49.3%). Fifteen patients (20.5%) died in hospital with DSWI. Treatment of DSWI consisted of open daily irrigation (up to 2006) or negative pressure wound therapy (NPWT) (2007 onwards), followed by primary closure or reconstruction of tissue flaps. We assessed the risk factors for in-hospital mortality from DSWI by comparing data from the 15 patients who died and the 58 survivors using propensity score matching analysis of the treatments used for DSWI.

RESULTS

Univariate analysis identified age, use of intra-aortic balloon pumping, prolonged mechanical ventilation, tracheotomy, prolonged intensive care unit stay, postoperative low output syndrome, postoperative myocardial infarction, postoperative renal failure, postoperative use of haemodialysis, postoperative pneumonia, postoperative cerebral disorder, MRSA infection, NPWT and tissue flaps as being associated with in-hospital mortality (P < 0.05). Multivariate analysis identified NPWT (odds ratio, 0.062; 95% confidence interval, 0.004-0.897; P = 0.041) and tissue flaps (odds ratio, 0.022; 95% confidence interval, 0.000-0.960; P = 0.048) as independently associated with reduced in-hospital mortality after DSWI. On comparing 22 patients receiving NPWT with 22 not on NPWT using propensity score matching, patients on NPWT had significantly lower in-hospital mortality than those without NPWT (NPWT vs non-NPWT, 5 vs 36%, P = 0.021). In DSWI infected by MRSA, NPWT significantly reduced the in-hospital mortality caused by DSWI (NPWT vs non-NPWT, 0 vs 52%, P = 0.003).

CONCLUSIONS

NPWT and tissue flaps may be favourable factors associated with reduced in-hospital mortality attributable to DSWI. NPWT as a bridge therapy to tissue flaps may play a major role in treating DSWI and improve the prognosis for patients with MRSA-infected DSWI.

Sternal cables are not superior to traditional sternal wiring for preventing deep sternal wound infection

OBJECTIVES

Deep sternal wound infection is a devastating complication of cardiac surgery. In the current era of increasing patient comorbidity, newer techniques must be evaluated in attempts to reduce the rates of deep sternal wound infection.

METHODS

A randomized controlled trial comparing sternal closure with traditional sternal wires in figure-8 formation with the Pioneer cabling system® from Medigroup after adult cardiac surgery was performed.

RESULTS

A total of 273 patients were enrolled with 137 and 135 patients randomized to sternal wires and cables group, respectively. Baseline characteristics between the two groups were well balanced. Deep sternal wound infection occurred in 0.7% of patients in the wires group and 3.7% of patients in the cables group (absolute risk difference = -3.0%, 95% confidence interval: -7.7 to 0.9%; P = 0.12). Patients in the cables group were extubated slightly earlier than those in the sternal wires group postoperatively (9.7 vs 12.8 h; P = 0.03). There was, however, no significant difference in hospital and follow-up pain scores or analgesia requirements.

CONCLUSIONS

The Pioneer sternal cabling system appears to facilitate early extubation after adult cardiac surgery, but it does not reduce the rate of deep sternal infectionAustralian New Zealand Clinical Trials Registry: ANZCTR-ACTRN12615000973516.

Reconstruction of massive post-sternotomy defects with allogeneic bone graft: four-year results and experience using the method

OBJECTIVES

Deep sternal wound infection poses a serious problem in cardiac surgery, with an up to 40% risk of mortality. Massive loss of sternum bone tissue and adjacent ribs results in major chest wall instability causing respiratory insufficiency and defects of soft tissue healing. Proposals for managing the situation have been published but the complexity of the issue precludes unequivocal resolution. Capitalizing on orthopaedic experience, we used allogeneic bone graft of sternum as a viable option.

METHODS

We performed the transplantation of allogeneic bone graft in 10 patients. In 9 cases, an allograft of sternum was used and in 1 case an allograft of calva bone. After the primary cardiac surgery, a massive post-sternotomy defect of the chest wall had developed in all 10 patients. Vacuum wound drainage was applied in the treatment of all patients. To stabilize the transverse, titanium plates were used. Bone allograft was prepared by the official Tissue Centre. Crushed allogeneic spongy bone was applied to reinforce the line of contact of the graft and the edges of residual skeleton. In 9 cases, the soft tissue was closed by direct suture of mobilized pectoral flaps. In 1 case, V-Y transposition of pectoral flap was performed.

RESULTS

In 6 cases, healing of the reconstructed chest wall occurred without further complications. In 3 cases, additional re-suture of the soft tissues and skin in the lower pole of the wound was necessary. Excellent chest wall stability along with the adjustment of respiratory insufficiency and good cosmetic effect was achieved in all cases. In 1 case, severe concomitant complications and no healing of the wound resulted in death within 6 months after the reconstruction. Median follow-up of all patients in the series was 14.1 months (1-36 months). In 4 patients, scintigraphy of the chest wall was performed.

CONCLUSIONS

Our existing results show that allogeneic bone graft transplantation is a promising and easily applied method in the management of serious tissue loss in sternal dehiscence with favourable functional and cosmetic effects. The relatively small number of patients with such severe healing complications of sternotomy however puts critical limits to a more detailed comparison with other practices and evaluation of long-term results.

A retrospective study of deep sternal wound infections: clinical and microbiological characteristics, treatment, and risk factors for complications

Deep sternal wound infection (DSWI) is a feared complication following cardiac surgery. This study describes clinical, microbiological, and treatment outcomes of DSWI and determines risk factors for complications. Of 55 patients with DSWI, 66% were male and mean age was 68.2 years. Initial sternotomy was for coronary artery bypass graft in 49% of patients. Sternal debridement at mean 25.4±18.3 days showed monomicrobial (94%), mainly Gram-positive infection. Secondary sternal wound infection (SSWI) occurred in 31% of patients, was mostly polymicrobial (71%), and was predominantly due to Gram-negative bacilli. Risk factors for SSWI were at least 1 revision surgery (odds ratio [OR] 4.8 [95% confidence interval {CI} 1.0-22.4], P=0.047), sternal closure by muscle flap (OR 4.6 [1.3-16.8], P=0.02), delayed sternal closure (mean 27 versus 14 days, P=0.03), and use of vacuum-assisted closure device (100% versus 58%, P=0.008). Hospital stay was significantly longer in patients with SSWI (69 days versus 48 days, P=0.04).

Therapeutic Outcomes of Pectoralis Major Muscle Turnover Flap in Mediastinitis

Background

This study aimed to evaluate the therapeutic results and safety of pectoralis major muscle turnover flaps in the treatment of mediastinitis after coronary artery bypass grafting (CABG) procedures.

Methods

Data regarding 33 patients with post-CABG deep sternal wound infections (DSWIs) who underwent pectoralis major muscle turnover flap procedures in the Emam Reza and Ghaem Hospitals of Mashhad, Iran were reviewed in this study. For each patient, age, sex, hospital stay duration, remission, recurrence, and associated morbidity and mortality were evaluated.

Results

Of the 2,447 CABG procedures that were carried out during the time period encompassed by our study, DSWIs occurred in 61 patients (2.5%). Of these 61 patients, 33 patients (nine females [27.3%] and 24 males [72.7%]) with an average age of 63±4.54 years underwent pectoralis major muscle turnover flap placement. Symptoms of infection mainly occurred within the first 10 days after surgery (mean, 10.24±13.62 days). The most common risk factor for DSWIs was obesity (n=16, 48.4%) followed by diabetes mellitus (n=13, 39.4%). Bilateral and unilateral pectoralis major muscle turnover flaps were performed in 20 patients (60.6%) and 13 patients (39.4%), respectively. Complete remission was achieved in 25 patients (75.7%), with no recurrence in the follow-up period. Four patients (12.1%) needed reoperation. The mean hospitalization time was 11.69±6.516 days. Four patients (12.1%) died during the course of the study: three due to the postoperative complication of respiratory failure and one due to pulmonary thromboembolism.

Conclusion

Pectoralis major muscle turnover flaps are an optimal technique in the treatment of post-CABG mediastinitis. In addition to leading to favorable therapeutic results, this flap is associated with minimal morbidity and mortality, as well as a short hospitalization time.

Continuous postoperative insulin infusion reduces deep sternal wound infection in patients with diabetes undergoing coronary artery bypass grafting using bilateral internal mammary artery grafts: a propensity-matched analysis

OBJECTIVES

Deep sternal wound infection (DSWI), especially in patients with diabetes mellitus (DM), is a major concern after coronary artery bypass grafting (CABG) with bilateral internal mammary artery (BIMA) grafts. We evaluated the risk of DSWI and other clinical outcomes between continuous insulin infusion therapy (CIT) and insulin sliding scale therapy (IST) in a cohort of DM patients who underwent CABG with BIMA.

METHODS

The clinical records of DM patients who underwent isolated CABG with BIMA were retrospectively reviewed. The study population consisted of 95 patients who received CIT and 126 patients who received IST. Furthermore, a one-to-one matched analysis based on estimated propensity scores for patients who received CIT or IST yielded two groups comprising 58 patients each. The proportion of patients with DSWI, overall survival rates and major adverse cardiac events were compared between the two groups in the overall and the propensity-matching cohort.

RESULTS

The prevalence of DSWI requiring debridement and closure was significantly reduced in the CIT group compared with that in the IST group [1/95 (1.1%) vs 9/126 (7.1%), P = 0.031]; these results were not attenuated even after propensity-matching analysis [0/58 (0%) vs 6/58 (10.3%), P = 0.031]. The mean preoperative glucose levels were similar between the two groups (157.5 ± 54.6 vs 176.1 ± ±70 mg/dl, P = 0.063), whereas the mean glucose values were significantly lower on the first and second operative days in the CIT group than in the IST group (132.9 ± 44.1 vs 197.8 ± 78.6 mg/dl, P < 0.0001; 153.5 ± 58.8 vs 199.6 ± 89.1 mg/dl, P < 0.0001, respectively). The glucose variability levels within 24 h postoperatively were significantly higher in the IST group (46.1 ± 19.4 vs 66.4 ± 26.8 mg/dl, P < 0.0001). The 30-day and 1-year survival rates were similar between the two groups (100 vs 99.2%, P = 0.384; 96.6 vs 94.4%, P = 0.454). No results were changed in the propensity-matching models.

CONCLUSIONS

The CIT approach reduced the variability in glucose concentration and resulted in fewer instances of DSWI after CABG with BIMA grafts.

Successful three-year outcome in a patient with allogenous sternal bone graft in the treatment of massive post-sternotomy defects

INTRODUCTION

Deep sternal wound infection is a life-threatening complication of longitudinal median sternotomy with extensive loss of sternal bone tissue and adjacent ribs. Wound dehiscence cases with no loss of bone tissue can be resolved via osteosynthesis using titanium plates. Unfortunately, this cannot be used in cases of massive bone tissue loss defects due to insufficient support for fixing the plate material caused by missing bone surface which increasing the risk of osteosynthesis failure. We describe the treatment outcome of sternal dehiscence with massive bone tissue loss defects using an allogenous sternal bone graft.

CASE PRESENTATION

A 62 year old diabetic female was operated for serious sternotomy dehiscence after surgery for aortic valve replacement. There was bone tissue loss and complications. We used allogenous sternal bone graft to close the wound. To monitor the healing of the graft, we performed SPECT/CT examinations of anterior chest wall. We describe the successful healing of the graft with the reduction of defects in osteoblastic activity by 42% 21 months after the graft implantation. The wound was found to be healed on all examinations, The chest wall is stable and the patient reports a good life quality.

DISCUSSION

An allogenous bone transplant contains no vital bone marrow cells, which eliminates immuno-genetic graft rejection by the patient. Significant osteoblastic activity was thus registered, especially in places where crushed spongy bone had been applied.

CONCLUSIONS

Transplantation of allogenous bone graft sternum in our experience is the best option for treating extensive post-sternotomy defects.

Cefazolin and linezolid penetration into sternal cancellous bone during coronary artery bypass grafting

OBJECTIVES

Deep sternal wound infection is a severe complication after cardiac surgery. Insufficient antibiotic target site concentrations may account for variable success of perioperative prophylaxis. Therefore, we measured perioperative penetration of cefazolin and of linezolid into sternal cancellous bone after sternotomy in coronary artery bypass grafting (CABG) patients by in vivo microdialysis.

METHODS

Nine patients underwent CABG using a skeletonized left internal mammary artery. Standard antibiotic prophylaxis consisted of 4 g cefazolin prior to skin incision and additional 2 g during skin closure. In addition, 600 mg of linezolid were administered prior to skin incision and after 12 h for study purposes. Two microdialysis probes were inserted into the sternal cancellous bone (left and right side) after sternotomy.

RESULTS

First mean peak cefazolin and linezolid plasma concentrations were 273 ± 92 µg/ml and 22.1 ± 8.9 µg/ml, respectively. Mean peak concentrations of antibiotics in sternal cancellous bone on the left and right sternal side were 112 ± 59 µg/ml and 159 ± 118 µg/ml for cefazolin and 10.9 ± 4.0 µg/ml and 12.6 ± 6.1 µg/ml for linezolid, respectively. Cefazolin exceeded the required tissue concentrations for relevant pathogens by far, but linezolid did not gain effective tissue concentrations in all patients for some relevant pathogens. Mammary artery harvesting had no significant effect on antibiotic tissue penetration.

CONCLUSIONS

Direct measurement of antibiotic concentration in sternal cancellous bone with in vivo microdialysis is technically demanding but safe and feasible. We could demonstrate sufficient antibiotic coverage with our standard cefazolin-dosing regimen in the sternal cancellous bone during cardiac surgery. Mammary artery harvesting had no clinically relevant effect on tissue penetration. Linezolid concentrations were not sufficient for some relevant pathogens.

Trends in postcoronary artery bypass graft sternal wound dehiscence in a provincial population

BACKGROUND

It appears that the medical profile of patients undergoing coronary artery bypass graft (CABG) surgery has changed. The impact of this demographic shift on CABG outcomes, such as sternal wound dehiscence, is unclear.

OBJECTIVES

To quantify the incidence and trends of sternal wound dehiscence, quantify the demographic shift of those undergoing CABG and identify patient factors predictive of disease.

METHODS

A prospective analysis was performed on a historical cohort of consecutive patients who underwent CABG (without valve replacement) in Alberta between April 1, 2002 and November 30, 2009. The incidence and trends of sternal wound dehiscence were determined. In addition, the trend of the mean Charlson index score and European System for Cardiac Operative Risk Evaluation (EuroSCORE) (capturing patient comorbidities) was analyzed. Univariable analysis and multivariable models were performed to determine factors predictive of wound dehiscence.

RESULTS

A total of 5815 patients underwent CABG during the study period. The incidence proportion of sternal wound dehiscence in Alberta was 1.86% and the incidence rate was 1.98 cases per 100 person-years. Although both the EuroSCORE and Charlson scores significantly increased over the study period, the incidence of sternal wound dehiscence did not change significantly. Factors predictive of sternal wound dehiscence were diabetes (OR 2.97 [95% CI 1.73 to 5.10]), obesity (OR 1.55 [95% CI 1.05 to 2.27]) and female sex (OR 1.90 [95% CI 1.26 to 2.87]).

CONCLUSIONS

The incidence proportion of sternal wound dehiscence in Alberta was comparable with the incidence previously published in the literature. While patients undergoing CABG had worsening medical profiles, the incidence of sternal wound dehiscence did not appear to be increasing significantly.

Is there a role for HbA1c in predicting mortality and morbidity outcomes after coronary artery bypass graft surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was is there a role for HbA1c in predicting morbidity and mortality outcomes after coronary artery bypass surgery? Eleven studies presented 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. The studies presented analyse the relationship between preoperative HbA1c levels and postoperative outcomes following coronary artery bypass graft (CABG) in diabetic, non-diabetic or mixed patient groups. Four studies found significant increases in early and late mortality at higher HbA1c levels, regardless of a preoperative diagnosis of diabetes. One study demonstrated that 30-day survival outcomes were significantly worse in patients with previously undiagnosed diabetes and elevated HbA1c compared with those with good control [HbA1c >6%; odds ratio 1.53, confidence interval (CI) (1.24-1.91); P = 0.0005]. However, four studies of early mortality outcomes in diabetic patients only showed no significant differences between patients with normal and those with deranged HbA1c levels (P = 0.99). There were mixed reports on morbidity outcomes. Three studies identified a significant increase in infectious complications in patients with poorly controlled HbA1c, two of which were irrespective of previous diabetic status [deep sternal wound infection (P = 0.014); superficial sternal wound infection (P = 0.007) and minor infections (P = 0.006) in poorly controlled diabetics only]. Four studies presented outcomes for total length of stay (LOS). Three of these papers looked specifically at diabetic patients, of which two found no significant differences in length of stay between good and poor preoperative glycaemic control [LOS: P = 0.59 and 0.86 vs P < 0.001]. However, elevated HbA1c vs normal HbA1c was associated with prolonged stay in hospital and in intensive care unit (ICU) in patients irrespective of previous diabetic status [total LOS (P < 0.001)]. Elevated HbA1c levels were also a significant predictor of reduced intraoperative insulin sensitivity in diabetic patients (R = -0.527; P < 0.001). Furthermore, higher HbA1c levels were associated with a reduced incidence of postoperative atrial fibrillation (P = 0.001). We conclude that elevated HbA1c is a strong predictor of mortality and morbidity irrespective of previous diabetic status. In particular, the mortality risk for CABG is quadrupled at HbA1c levels >8.6%. Some studies have called into question the predictive value of HbA1c on short-term outcomes in well-controlled diabetics; however, long-term outcomes in this population have not been reported.

In patients with post-sternotomy mediastinitis is vacuum-assisted closure superior to conventional therapy?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether vacuum-assisted closure therapy (VAC) is superior to conventional therapy for treating post-sternotomy mediastinitis. Altogether >261 papers were found using the reported search, of which 9 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 studies indicate that VAC therapy is associated with shorter lengths of intensive care and in-hospital stay as well as faster rates of wound healing and fewer dressing changes. It has also been shown that VAC therapy is correlated with a statistically significant reduction in reinfection rates, particularly those that occur in the early postoperative period (at the 1-week follow-up). Patients can be discharged with the dressing in situ and managed in the community with a view to delayed closure or reconstruction. However, the studies comparing VAC with conventional therapy are all retrospective in nature and reinforce the need for randomized controlled trials in order to more accurately establish differences in outcomes between VAC and conventional therapy. Additionally, owing tło the variability of treatment protocols within the non-VAC arm, it is more challenging to draw definitive conclusions regarding the superiority of VAC therapy to every modality that is considered conventional treatment. We conclude that VAC therapy is a portable and an increasingly economical option for the treatment of post sternotomy mediastinitis. Although reductions in mortality rates were not reproduced in all studies, evidence suggests that VAC should still be considered as a first-line therapy for post-sternotomy mediastinitis and as a bridge therapy to musculocutaneous reconstruction or primary closure.

C-reactive protein and leucocyte counts drop faster using the HeartShield® device in patients with DSWI

Right ventricular heart rupture is a devastating complication associated with negative pressure wound therapy (NPWT) in cardiac surgery. The use of a rigid barrier disc (HeartShield™) has been suggested to offer protection against this lethal complication by preventing the heart from being drawn up by the negative pressure and damaged by the sharp sternum bone edges. Seven patients treated with conventional NPWT and seven patients treated with NPWT with a protective barrier disc (HeartShield) were compared with regard to bacterial clearance and infection parameters including C-reactive protein levels and leucocyte counts. C-reactive protein levels and leucocyte counts dropped faster and bacterial clearance occurred earlier in the HeartShield® group compared with the conventional NPWT group. Negative biopsy cultures were shown after 3·1 ± 0·4 NPWT dressing changes in the HeartShield group, and after 5·4 ± 0·6 NPWT dressing changes in the conventional NPWT group (P < 0·001). All patients were followed up with clinical check-up after 3 months. None of the patients in the HeartShield group had any signs of reinfection such as deep sternal wound infection (DSWI) or sternal fistulas, whereas in the conventional NPWT group, two patients had signs of sternal fistulas that demanded hospitalisation. HeartShield hinders the right ventricle to come into contact with the sharp sternal edges during NPWT and thereby protects from heart damage. This study shows that using HeartShield is beneficial in treating patients with DSWI. Improved wound healing by HeartShield may be a result of the efficient drainage of wound effluents from the thoracic cavity.

Suction-irrigation drainage: an underestimated therapeutic option for surgical treatment of deep sternal wound infections

OBJECTIVES

Deep sternal wound infections are significant and severe complications following cardiac surgery and substantially influence perioperative morbidity and mortality. We present the experience of our department using two different surgical treatments over a three-year period.

METHODS

Between January 2009 and December 2011, a total of 3274 cardiac procedures with complete median sternotomy were performed in our department. In 94 patients (3%), a deep sternal wound infection occurred, including sternal instability with consecutive surgical treatment. The patients either received wound debridement with sternum refixation and suction-irrigation drainage (SID; n = 72) or sternum refixation only (RF; n = 22) if there was sternal instability with limited signs of infection. SID was routinely installed for 7 days: the irrigation solution contained neomycin. In all cases, swabs were taken and analysed. The different methods were evaluated in respect of their clinical outcomes.

RESULTS

The success rate-defined as single, uncomplicated procedure-of the SID treatment was 74%, compared with 59% of the isolated sternum refixation. Complications included continuous infection, recurrence of sternal instability and wound necrosis. Eighty-eight percent of the swabs in the SID group were positive, compared with 32% in the sternal refixation only group. The dominating pathogenic germs were coagulase-negative staphylococci and staphylococcus aureus. Mortality was 10% for the SID group and 5% for the RF group.

CONCLUSIONS

Contrary to accepted opinion, the suction-irrigation drainage is an appropriate therapy for deep sternal wound infections. Nevertheless, deep sternal wound infections after cardiac surgery remain severe complications and are related to increased morbidity and mortality.