Infectious Mediastinitis: A Retrospective Cohort Study

Background

This study aimed to characterize the demographics, microbiology, management and treatment outcomes of mediastinitis according to the origin of the infection.

Methods

This retrospective observational study enrolled patients who had mediastinitis diagnosed according to the criteria defined by the Centers for Disease Control and Prevention and were treated in Strasbourg University Hospital, France, between 1 January 2010 and 31 December 2020.

Results

We investigated 151 cases, including 63 cases of poststernotomy mediastinitis (PSM), 60 cases of mediastinitis due to esophageal perforation (MEP) and 17 cases of descending necrotizing mediastinitis (DNM). The mean patient age (standard deviation) was 63 (14.5) years, and 109 of 151 patients were male. Microbiological documentation varied according to the origin of the infection. When documented, PSM cases were mostly monomicrobial (36 of 53 cases [67.9%]) and involved staphylococci (36 of 53 [67.9%]), whereas MEP and DNM cases were mostly plurimicrobial (38 of 48 [79.2%] and 8 of 12 [66.7%], respectively) and involved digestive or oral flora microorganisms, respectively. The median duration of anti-infective treatment was 41 days (interquartile range, 21-56 days), and 122 of 151 patients (80.8%) benefited from early surgical management. The overall 1-year survival rate was estimated to be 64.8% (95% confidence interval, 56.6%-74.3%), but varied from 80.1% for DNM to 61.5% for MEP.

Conclusions

Mediastinitis represents a rare yet deadly infection. The present cohort study exhibited the different patterns observed according to the origin of the infection. Greater insight and knowledge on these differences may help guide the management of these complex infections, especially with respect to empirical anti-infective treatments.

Artificial intelligence-based analysis of body composition predicts outcome in patients receiving long-term mechanical circulatory support

BACKGROUND

Obesity is a known cardiovascular risk factor and associated with higher postoperative complication rates in patients undergoing cardiac surgery. In heart failure (HF), conflicting evidence in terms of survival has been reported, whereas sarcopenia is associated with poor prognosis. An increasing number of HF patients require left ventricular assist device (LVAD) implantations. The postoperative mortality has improved in recent years but is still relatively high. The impact of body composition on outcome in this population remains unclear. The aim of this investigation was to examine the preoperative computed tomography (CT) body composition as a predictor of the postoperative outcome in advanced HF patients, who receive LVAD implantations.

METHODS

Preoperative CT scans of 137 patients who received LVADs between 2015 and 2020 were retrospectively analysed using an artificial intelligence (AI)-powered automated software tool based on a convolutional neural network, U-net, developed for image segmentation (Visage Version 7.1, Visage Imaging GmbH, Berlin, Germany). Assessment of body composition included visceral and subcutaneous adipose tissue areas (VAT and SAT), psoas and total abdominal muscle areas and sarcopenia (defined by lumbar skeletal muscle indexes). The body composition parameters were correlated with postoperative major complication rates, survival and postoperative 6-min walk distance (6MWD) and quality of life (QoL).

RESULTS

The mean age of patients was 58.21 ± 11.9 years; 122 (89.1%) were male. Most patients had severe HF requiring inotropes (Interagency Registry for Mechanically Assisted Circulatory Support [INTERMACS] profile I-III, 71.9%) secondary to coronary artery diseases or dilated cardiomyopathy (96.4%). Forty-four (32.1%) patients were obese (body mass index ≥ 30 kg/m2 ), 96 (70.1%) were sarcopene and 19 (13.9%) were sarcopene obese. Adipose tissue was associated with a significantly higher risk of postoperative infections (VAT 172.23 cm2 [54.96, 288.32 cm2 ] vs. 124.04 cm2 [56.57, 186.25 cm2 ], P = 0.022) and in-hospital mortality (VAT 168.11 cm2 [134.19, 285.27 cm2 ] vs. 135.42 cm2 [49.44, 227.91 cm2 ], P = 0.033; SAT 227.28 cm2 [139.38, 304.35 cm2 ] vs. 173.81 cm2 [97.65, 254.16 cm2 ], P = 0.009). Obese patients showed no improvement of 6MWD and QoL within 6 months postoperatively (obese: +0.94 ± 161.44 months, P = 0.982; non-obese: +166.90 ± 139.00 months, P < 0.000; obese: +0.088 ± 0.421, P = 0.376; non-obese: +0.199 ± 0.324, P = 0.002, respectively). Sarcopenia did not influence the postoperative outcome and survival within 1 year after LVAD implantation.

CONCLUSIONS

Preoperative AI-based CT body composition identifies patients with poor outcome after LVAD implantation. Greater adipose tissue areas are associated with an increased risk for postoperative infections, in-hospital mortality and impaired 6MWD and QoL within 6 months postoperatively.

The usefulness of chest drain and epicardial pacing wire culture for diagnosing mediastinitis after open-heart surgery

PURPOSE

Culture of extracted drains or epicardial pacing wires is an easy and noninvasive method for detecting mediastinitis after open-heart surgery, although studies on its sensitivity and specificity are limited. We, therefore, investigated the usefulness of this approach for diagnosing mediastinitis.

METHODS

We retrospectively studied the culture results of drains and epicardial pacing wires extracted from 3308 patients. Prediction models of mediastinitis with and without culture results added to clinical risk factors identified by a logistic regression analysis were compared.

RESULTS

The incidence of mediastinitis requiring surgery was 1.89% (n = 64). Staphylococcus was the causative bacterium in 64.0% of cases. The sensitivity, specificity, and positive and negative predictive values of positive culture results were 50.8%, 91.8%, 10.7%, and 99.0%, respectively. Methicillin-resistant Staphylococcus aureus had the highest positive predictive value (61.5%). A multivariate analysis identified preoperative hemodialysis (OR 5.40 [2.54-11.5], p < 0.01), long operative duration (p < 0.01), postoperative hemodialysis (OR 2.25 [1.01-4.98], p < 0.05), and positive culture result (OR 10.2 [5.88-17.7], p < 0.01) as independent risk factors. The addition of culture results to pre- and postoperative hemodialysis and a lengthy operative time improved the prediction of mediastinitis.

CONCLUSIONS

A culture survey using extracted drains and epicardial pacing wires may provide useful information for diagnosing mediastinitis.

Demographic, clinical, and paraclinical features of patients operated with the diagnosis of acute descending necrotizing mediastinitis: a retrospective study in Southern Iran

INTRODUCTION

Descending necrotizing mediastinitis (DNM) is a type of acute mediastinitis that is rarely reported but is regarded as a fatal disease despite improvements in technological methods and antibiotic therapies. We aimed to determine the demographic, clinical, and paraclinical features of patients diagnosed with acute DNM.

METHODS

In this retrospective study, patients' hospital records with a diagnosis of DNM admitted to the Namazi hospital in southern Iran during 18 years (2002-2019) were reviewed. Demographic and clinical features were recorded and subsequently analyzed via SPSS 22.

RESULTS

Out of 67 mediastinitis patients, 25 (37.3%) were diagnosed as DNM with an average age of 37.2 ± 16.7 years, and 68% were male. Regarding etiology, 52.0% were due to neck infection. Based on the technique of surgery, 52% of the patients underwent the combined method, which was mostly among type I and IIA DNM, while thoracotomy was mostly performed on type IIB DNM (P = 0.08). Based on the incision, type IIA and IIB had the highest frequency of thoracotomy and cervicothoracic incisions (P = 0.02 and 0.002). Puss discharge was significantly lower in type I DNM (P = 0.01). Based on the presenting symptoms of our patients, the majority (72.0%) had a chief complaint of neck pain, followed by chills and fever (48%). There were no reports of mortality during our short-term follow-up.

CONCLUSION

We report one of the largest retrospective studies of DNM patients in our referral center, with a high prevalence of the disease among younger populations, especially under 40 years. The method of treatment should be chosen based on the extent of infection and can be limited to neck exploration in upper mediastinal infections, though thoracic or combined approach in more broad infections.

Subvalvular techniques enhanced with endoscopic robotic mitral valve repair

Objective

Totally endoscopic intracardiac robotic surgery is generally limited to uncomplicated mitral valve surgery. With experience, our team has developed a more aggressive approach to robotic cardiac surgery that allows for repair of a broad spectrum of mitral valve pathologies. We report complex subvalvular procedural advancements associated with this approach secondary to enhanced team experience and capabilities.

Methods

All robotic mitral procedures performed by a 2-surgeon team in a quaternary care medical center from July 2011 to May 2022 were reviewed. Natural language-processing techniques were used to analyze operative reports for subvalvular repair techniques. Complex subvalvular techniques included papillary muscle repositioning, division of secondary anterior leaflet chordae, septal myomectomy, division of aberrant left ventricular muscle band attachments, and left ventricular patch reconstruction. The surgical experience was divided into 2 periods: early robotic experience (pre-2018) versus late (2018 onwards). Baseline demographics, outcomes, and subvalvular techniques were analyzed and compared.

Results

A total of 1287 intracardiac robotic operations were performed by a 2-surgeon team. Thirty-day mortality was 0.6% (8/1287). Mitral valve repair was performed in 1024 patients. The mean age was 61 years (range, 18-90 years), and 15% were >75 years old; 29 patients (2.8%) had previously undergone cardiac surgery. There was a significant increase with experience in the application of advanced subvalvular techniques between the early versus late period (52.3% [268/512] vs 74.2% [380/512] (P < .001)).

Conclusions

An experienced 2-surgeon team can perform progressively more complex robotic subvalvular repair techniques. These subvalvular techniques are a surrogate for team proficiency and capabilities.

Risk factors for sternal wound infection after open-heart operations: A systematic review and meta-analysis

We aimed to quantitatively and systematically elucidate the rationality of the examined variables as independent risk factors for sternal wound infection. We searched databases to screen studies, ascertained the variables to be analysed, extracted the data and applied meta-analysis to each qualified variable. Odds ratios and mean differences were considered to be the effect sizes for binary and continuous variables, respectively. A random-effects model was used for these procedures. The source of heterogeneity was evaluated using a meta-regression. Publication bias was tested by funnel plot and Egger's test, the significant results of which were then calculated using trim and fill analysis. We used a sensitivity analysis and bubble chart to describe their robustness. After screening all variables in the eligible literature, we excluded 55 because only one or no research found them significant after multivariate analysis, leaving 33 variables for synthesis. Two binary variables (age over 65 years, NYHA class >2) and a continuous variable (preoperative stay) were not significant after the meta-analysis. The most robust independent risk factors in our study were diabetes mellitus, obesity, use of bilateral internal thoracic arteries, chronic obstructive pulmonary disease, prolonged surgery time, prolonged ventilation and critical preoperative state, followed by congestive heart failure, atrial fibrillation, renal insufficiency, stroke, peripheral vascular disease and use of an intra-aortic balloon pump. Relatively low-risk factors were emergent/urgent surgery, smoking, myocardial infarction, combined surgery and coronary artery bypass grafting. Sternal wound infection after open-heart surgery is a multifactorial disease. The detected risk factors significantly affected the wound healing process, but some were different in strength. Anything that affects wound healing and antibacterial ability, such as lack of oxygen, local haemodynamic disorders, malnutrition condition and compromised immune system will increase the risk, and this reminds us of comprehensive treatment during the perioperative period.

Effect of an E-Prescription Intervention on the Adherence to Surgical Chemoprophylaxis Duration in Cardiac Surgery: A Single Centre Experience

In our hospital, adherence to the guidelines for peri-operative antimicrobial prophylaxis (PAP) is suboptimal, with overly long courses being common. This practice does not offer any incremental benefit, and it only adds to the burden of antimicrobial consumption, promotes the emergence of antimicrobial resistance, and it is associated with adverse events. Our objective was to study the effect of an electronic reminder on the adherence to each element of PAP after cardiac surgery. We conducted a single center, before and after intervention, prospective cohort study from 1 June 2014 to 30 September 2017. The intervention consisted of a reminder of the hospital guidelines when ordering PAP through the hospital information system. The primary outcome was adherence to the suggested duration of PAP, while secondary outcomes included adherence to the other elements of PAP and incidence of surgical site infections (SSI). We have studied 1080 operations (400 pre-intervention and 680 post-intervention). Adherence to the appropriate duration of PAP increased significantly after the intervention [PRE 4.0% (16/399) vs. POST 15.4% (105/680), chi-square p < 0.001]; however, it remained inappropriately low. Factors associated with inappropriate duration of PAP were pre-operative hospitalization for <3 days, and duration of operation >4 h, while there were significant differences between the chief surgeons. Unexpectedly, the rate of SSIs increased significantly during the study (PRE 2.8% (11/400) vs. POST 5.9% (40/680), chi-square p < 0.019). The implemented intervention achieved a relative increase in adherence to the guideline-recommended PAP duration; however, adherence was still unacceptably low and further efforts to improve adherence are needed.

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.

Incidence and predictors of sternal surgical wound infection in cardiac surgery: A prospective study

Sternal surgical wound infection (SSWI) in cardiac surgery is associated with increased morbidity. We investigated the incidence of SSWI, the main germs implicated and predictors of SSWI. Prospective study including patients undergoing full median sternotomy between January 2017 and December 2019. Patients were followed-up for 3 months after hospital discharge. All sternal wound infections up to 90 days after discharge were considered SSWI. 1004 patients were included. During follow-up, 68 (6.8%) patients presented SSWI. Patients with SSWI had a higher incidence of postoperative renal failure (29.4% vs 17.1%, P = .007), a higher incidence of early postoperative reoperation for non-infectious causes (42.6% vs 9.1%, P < .001), longer ICU stay (3 [2-9] days vs 2 [2-4] days, P = .006), and longer hospital stay (24.5 [14.8-38.3] days vs 10 [7-18] days, P < .001). Gram-positive germs were presented in 49% of the cultures, and gram-negative bacteria in 35%. Early reoperation for non-infectious causes (OR 4.90, 95% CI 1.03-23.7), and a longer ICU stay (OR 1.37 95% CI 1.10-1.72) were independent predictors of SSWI. SSWI is rare but leads to more postoperative complications. The need for early reoperation because of non-infectious cause and a longer ICU stay were independently associated with SSWI.

Pyoderma Gangrenosum after Cardiac Surgery

BACKGROUND

Pyoderma gangrenosum after cardiac surgery is a rare, noninfectious ulcerating skin disease mimicking sternal wound infection.

METHODS

A systematic search of literature for pyoderma gangrenosum complicating cases of cardiac surgery was conducted between September 1985 and September 2020 on PubMed and Cochrane databases. A systematic review and detailed overview of clinical presentation, diagnostic, treatment, and outcome is provided.

RESULTS

A total of 15 studies enclosing 15 patients suffering from pyoderma gangrenosum following cardiac surgery were identified. Onset of symptoms was observed after a median of 5 days. Patients were predominantly male (81.3%) with a median age of 64 years. Typical clinical presentation mimicked sternal site infection, mainly by means of mediastinitis. Specific signs were rapid progression, erythematous to violaceous color of the wound border, accompanied by unspecific symptoms including fever, malaise, and severe pain. Additionally, pathergy (development of ulcers at the sites of minor cutaneous trauma) was reported frequently. Biopsy is mandatory with a cutaneous neutrophilic inflammation confirming the diagnosis. Initial treatment mostly (75.0% of reported cases) was misled, addressing suspicion of surgical site infection. After correct diagnosis, the treatment was switched to an immunosuppressive therapy. Full sternal wound closure took between 5 weeks and 5 months. Reported case mortality was 12.5% in actually low-risk surgeries.

CONCLUSION

Despite pyoderma gangrenosum has typical signs, it remains an exclusion diagnosis. The treatment is completely opposite to the main differential diagnosis-the typical surgical site infection. Knowledge about diagnosis and treatment is essential in the context of avoiding fatal mistreatment.

A new clinical classification and reconstructive strategy for post-sternotomy surgical site infection

Introduction

Post-sternotomy surgical site infection (SSI) is a serious complication of cardiovascular surgery. Here, we proposed a new clinical classification and reconstructive strategy for this condition.

Methods

A retrospective study based on medical records was performed on 100 consecutive cases requiring wound management by plastic surgeons for post-sternotomy SSI at Kobe University Hospital between January 2009 and December 2021. We classified 100 cases into four categories according to the anatomical invasiveness of the infection (type 1, superficial SSI; type 2, sternal osteomyelitis; type 3, mediastinitis; and type 4, aortic graft infection). The standard treatment plan comprised initial debridement, negative pressure wound therapy with continuous irrigation, and reconstructive surgery. Reconstructive methods and their outcomes (in-hospital mortality rate, follow-up period, and infection recurrence rate) were investigated for each SSI category.

Results

There were nine SSI cases in type 1, 28 in type 2, 25 in type 3, and 38 in type 4. The pectoralis major (PM) muscle advancement flap was mainly selected in types 1 and 2 (100 and 70.4%, respectively), while the omental flap or latissimus dorsi (LD) myocutaneous flaps were mainly selected in types 3 and 4 (77.3 and 81.8%, respectively) for reconstructive surgery. The in-hospital mortality rates for types 1, 2, 3, 4 were 44.4, 3.6, 12.0, and 15.8%, respectively. The mean follow-up periods for types 1, 2, 3, 4 were 542.8, 1514.5, 1154.5, and 831.1 days, respectively. Infection recurrence rates for types 1, 2, 3, 4 were 0, 11.5, 13.3, and 19.2%, respectively. All of these recurrent cases, except for 4 cases of type 4 that required surgical intervention, were treated with conservative wound management.

Conclusion

A volume-rich flap (omental or LD flap) was required to fill the dead space after debridement in mediastinitis (type 3) or aortic graft infection (type 4), whereas superficial SSI (type 1) or sternal osteomyelitis (type 2) received a less-invasive flap (PM muscle advancement flap). Our new classification method was based on the anatomical invasiveness of the infection, providing both a simple and easy diagnosis and definitive treatment strategy.

•

A clinical classification for post-sternotomy surgical site infection is provided.

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The classification method is based on the anatomical invasiveness of the infection.

•

It provides a simple and easy diagnosis and definitive treatment strategy.

•

Reconstruction strategy was proposed to treat this condition.

Surgical Site Infection in Cardiac Surgery

Surgical site infections (SSIs) are one of the most significant complications in surgical patients and are strongly associated with poorer prognosis. Due to their aggressive character, cardiac surgical procedures carry a particular high risk of postoperative infection, with infection incidence rates ranging from a reported 3.5% and 26.8% in cardiac surgery patients. Given the specific nature of cardiac surgical procedures, sternal wound and graft harvesting site infections are the most common SSIs. Undoubtedly, DSWIs, including mediastinitis, in cardiac surgery patients remain a significant clinical problem as they are associated with increased hospital stay, substantial medical costs and high mortality, ranging from 3% to 20%. In SSI prevention, it is important to implement procedures reducing preoperative risk factors, such as: obesity, hypoalbuminemia, abnormal glucose levels, smoking and S. aureus carriage. For decolonisation of S. aureus carriers prior to cardiac surgery, it is recommended to administer nasal mupirocin, together with baths using chlorhexidine-based agents. Perioperative management also involves antibiotic prophylaxis, surgical site preparation, topical antibiotic administration and the maintenance of normal glucose levels. SSI treatment involves surgical intervention, NPWT application and antibiotic therapy.

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.

An Analysis of 400 Sternal Wound Reconstructions at a Single Institution: Bacterial Pathogens Vary With Time

BACKGROUND

Sternal wound (SW) infection and dehiscence after median sternotomy from cardiac surgery remain challenging complications with high morbidity. Knowledge of common pathogen types and variance with time from cardiac surgery can simplify the choice of antibiotics while awaiting definitive culture results.

METHODS

Records of 505 patients undergoing SW reconstruction by the senior author from 1996 to 2018 at a high-volume cardiac surgery center were reviewed. The most common indications for reconstruction were SW infection and dehiscence. At surgery, all patients underwent removal of sternal hardware, thorough debridement, and closure with bilateral pectoralis major myocutaneous advancement flaps. Deep tissue and bone cultures were sent in nearly all cases. Patients were split into group 1 or group 2 based on timing of flap reconstruction after initial cardiac surgery: 0 to 30 days and longer than 30 days, respectively.

RESULTS

Complete data were available for 400 SW procedures performed during this period. Group 1 included 203 patients, and group 2 had 197 patients, with a mean time to SW surgery of 16.3 and 138.1 days, respectively. Intraoperative cultures were positive in 147 of 203 (72.4%), and 122 of 197 (61.9%) patients, respectively. Forty-four patients grew polymicrobial cultures. There was a significant difference in culture positivity rates in the 2 groups (P = 0.0004). The most common bacteria cultured in group 1 was Staphylococcus epidermidis (54 of 203 vs 21 of 197; P < 0.0001), whereas methicillin-sensitive Staphylococcus aureus was most common in group 2 (15 of 203 vs 22 of 197; P = 0.23). Methicillin-resistant S. aureus was relatively common in both groups (17 of 203 vs 21 of 197; P = 0.50). Although not statistically significant, Pseudomonas, Klebsiella, and Candida were all found in a higher percentage of patients in group 2 (p = 0.11, 0.20, 0.20).

CONCLUSIONS

Microbial species cultured in SW flap reconstruction vary over time. Staphylococcus epidermidis is the most common infectious agent in patients having reconstruction within 30 days of cardiac surgery, whereas methicillin-sensitive S. aureus is most common after 30 days. The trend toward a higher incidence of Gram-negative and fungal organisms after 30 days may indicate a need for broader initial anti-infective coverage in this patient group. Awareness of these pathogen patterns can better inform antibiotic selection while awaiting culture data.

An Algorithmic Approach to the Surgical Management of Sternal Dehiscence: A Single-Center Experience

Background Deep sternal wound complications following sternotomy represent a complex challenge. Management can involve debridement, flap reconstruction, and rigid sternal fixation (RSF). We present our 11-year experience in the surgical treatment of deep sternal wound dehiscence using a standardized treatment algorithm.

Methods A retrospective review was conducted of all 134 cardiac patients who required operative debridement after median sternotomy at a single institution between October 2007 and March 2019. Demographics, perioperative covariates, and outcomes were recorded. Univariate and subgroup analyses were performed.

Results One-hundred twelve patients (83.5%) with a deep sternal dehiscence underwent flap closure and 56 (50%) RSF. Of the patients who underwent flap closure, 87.5% received pectoralis advancement flaps. A 30-day mortality following reconstruction was 3.9%. Median length of stay after initial debridement was 8 days (interquartile range: 5–15). Of patients with flaps, 54 (48%) required multiple debridements prior to closure, and 30 (27%) underwent reoperation after flap closure. Patients who needed only a single debridement were significantly less likely to have a complication requiring reoperation (N = 10/58 vs. 20/54, 17 vs. 37%, p = 0.02), undergo a second flap (N = 6/58 vs. 17/54, 10 vs. 32%, p < 0.001), or, if plated, require removal of sternal plates (N = 6/34 vs. 11/22, 18 vs. 50%, p = 0.02).

Conclusion Although sternal dehiscence remains a complex challenge, an aggressive treatment algorithm, including debridement, flap closure, and consideration of RSF, can achieve good long-term outcomes. In low-risk patients, RSF does not appear to increase the likelihood of reoperation. We hypothesize that earlier surgical intervention, before the development of systemic symptoms, may be associated with improved outcomes.

Clinical Use of Tailored Computed Tomography to Prevent Poststernotomy Dehiscence

BACKGROUND

 Morphological and tissue density analysis of the sternum can be performed in the preoperative computed tomography (CT). The purpose of this study was to analyze morphology and tissue density of sternum in CT and effect for comparison sternal instability.

METHODS

 Patients with sternal instability (n = 61) and sternal stability (n = 66) were enrolled in this study. All of the patients were studied using same thorax CT procedure. All the measurements were performed by one specific cardiovascular radiologist. The Hounsfield units (HUs) were measured in axial sections of the sternum trabecular bone.

RESULTS

 Sternal instability group mean HU was 75.36 ± 13.19 and sternal stability group HU was 90.24 ± 12.16 (p < 0.000). HU is the statically significant predictor of sternal instability.

CONCLUSION

 Our study showed a significant correlation between the mean HU value of sternum and sternal instability. We think that it is important to evaluate the existing thorax CT while performing preoperative risk analysis for sternal dehiscence.

Treatment of Cardiac Surgical Wounds with Silver Dressings

Introduction

Mediastinitis is a deadly surgical site infection (SSI) after cardiac surgery. Although rare, mortality is as high as 47%. Best practices for infection prevention to eliminate this deadly complication must be identified. Surgical dressings impregnated with silver have been shown to reduce SSIs in other surgical specialties. The aim of this study was to determine if the routine use of silver surgical dressings is beneficial to prevent mediastinitis after cardiac surgery.

Methods

A single-center retrospective study was performed on patients who underwent sternotomy from 2016 to 2018 at the University of Kansas Medical Center. Prior to June 2017, all cardiac surgical patients were treated with gauze surgical dressings and designated as Group A. The routine use of silver-impregnated surgical dressings was implemented in June 2017; patients after this change in practice were designated as Group B. Patient characteristics and rates of deep and superficial sternal wound infections (SWI) were compared.

Results

There were 464 patients in Group A and 505 in Group B. There were seven SWIs in Group A (7/464, 1.5%) and five in Group B (5/505, 1%; p = 0.57). Of these, there was one deep SWI per group (p = 0.61) and six superficial SWIs in Group A compared to four in Group B (p = 0.74). Severe COPD was higher in Group A (p = 0.04) and peak glucose was higher in Group B (p = 0.02).

Conclusions

The analysis conferred no benefit with silver-impregnated surgical dressings to prevent mediastinitis. Choice of gauze surgical dressings may be preferable to reduce cost.

Gram-negative bacteria as a cause of mediastinitis after cardiac surgery

PURPOSE OF REVIEW

Poststernotomy mediastinitis (PSM) remains a serious infection and is significantly associated with high morbidity, short-term and long-term mortality. Gram-negative bacteria (GNB) are an underestimated cause of PSM, and there is little information on the risk factors, prevention, diagnosis and management of GNB PSM.

RECENT FINDINGS

The pathogenesis of PSM is the result of a complex and multifactorial interplay between intraoperative wound contamination, host-related and surgical host factors but GNB are probably mostly translocated from other host site infections. GNB are frequent cause of PSM (18-38% of cases) and GNB PSM have shown to more frequently polymicrobial (20-44%). GNG PSM has shown to occur earlier than Gram-positive PSM. Early diagnosis is crucial to successful treatment. The management of PSM needs a combination of culture-directed antimicrobial therapy and an early extensive surgical debridement with either immediate or delayed closure of the sternal space. Antibiotic treatment choice and duration should be based on clinical evaluation, evolution of inflammatory markers, microbiological tests and imaging studies. Mortality has shown to be significantly higher with GNB PSM compared with other causes and the inappropriateness of initial antibiotic therapy may explain the worse outcome of GNB PSM.

SUMMARY

GNB PSM is usually undervalued in the setting of PSM and have shown to be a frequent cause of inappropriate treatment with adverse prognostic potential. There is a need for efforts to improve knowledge to prevent and adequately treat GNB PSM.

Current Management of Sternal Wounds

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Describe the pathogenesis, classification, and risk factors of sternal wound infection. 2. Discuss options for sternal stabilization for the prevention of sternal wound infection, including wiring and plating techniques. 3. Discuss primary surgical reconstructive options for deep sternal wound infection and the use of adjunctive methods, such as negative-pressure wound therapy.

SUMMARY

Poststernotomy sternal wound infection remains a life-threatening complication of open cardiac surgery. Successful treatment relies on timely diagnosis and initiation of multidisciplinary, multimodal therapy.

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.

Negative pressure wound therapy in the treatment of deep sternal wound infections - a critical appraisal

Introduction. Negative pressure wound therapy (NPWT) has widely become the first-line option in the treatment of deep sternal wound infections. After several positive reports in comparison with conventional treatment, very recent studies comparing NPWT with early reconstruction have favored the latter. Our aim was to evaluate the effectiveness and safety of NPWT in comparison with early flap reconstruction. Materials and methods. We concluded a retrospective analysis of 125 patients with deep sternal wound infection treated in a single institution between the years 2006 and 2018. NPWT became the first-line treatment in our hospital in 2011. The study group consisted of 55 patients treated primarily with NPWT with or without subsequent flap reconstruction. The control group consisted of 60 patients treated with flap reconstruction without prior NPWT. Ten patients with an immediate re-fixation and direct wound closure were excluded. Results. There were no significant differences between the two groups concerning the type or urgency of the original open-heart surgery, age, gender, or co-morbidities. In the NPWT group there was significantly higher mortality (p = .002), longer stay in the intensive care unit (p = .028), and in the university hospital (p < .001) as well as higher number of operations (p < .001). However, there were somewhat more surgical complications in the control group as well as a higher number of distant flap reconstructions. Overall, five patients suffered from NPWT associated bleeding. Conclusion. Our results raise concerns about the wide use of NPWT as a first-line treatment of deep sternal wound infections. Further evaluative studies are warranted to confirm the results.

Non-tumorous diseases of the sternum and its articulations: At the front gate of the chest

Abnormalities of the sternal and peri-sternal regions are commonly seen in clinical practice and may be one of the important causes of chest pain particularly anterior chest wall pain. While reading computed tomography (CT) of the chest for evaluation of chest pain, the sternal region is either easily overlooked or its abnormality is often detected incidentally. This article will provide an overview of normal sternal anatomy and congenital variants as well as a variety of non-tumorous pathologic conditions of the sternum and adjacent joints, with emphasis on CT, to help radiologists, particularly thoracic radiologists, to make an accurate diagnosis in their daily practice. Non-tumorous abnormalities include trauma (fractures and dislocations), infection (osteomyelitis, septic arthritis), degenerative (osteoarthritis) and inflammatory conditions (rheumatoid arthritis, seronegative arthritides), and metabolic disorders (Paget's disease and renal osteodystrophy) as well as treatment related changes such as poststernotomy and its complications (dehiscence, nonunion) and postradiation changes of the sternum.

Robotic mitral valve operations can be safely performed in obese patients

INTRODUCTION

Robotic cardiac surgery offers mitigated risks for obese patients requiring mitral valve surgery. We aimed to study the safety of robotic mitral surgery in the obese patient population by analyzing the outcomes of mitral surgery patients in our center for robotic cardiac surgery.

METHOD

This study retrospectively included 123 consecutive patients who underwent robotic mitral valve operations in a single center for robotic cardiac surgery. Patients with body mass index (BMI) ≥ 30 were compared against patients with BMI < 30 for demographic and operative parameters as well as postoperative outcomes.

RESULTS

Mean BMI was 33.9 ± 2.8 in the obesity group (n = 87) and 25.4 ± 2.7 in the no-obesity group (n = 36). Female gender (80.6% vs. 52.9%, p = .004), diabetes (25.0% vs. 10.3%, p = .036), and hypertension (48.6% vs. 26.4%, p = .018) were more common in patients with obesity. The obesity group was operated with similar cardiopulmonary bypass and total operative times with the no-obesity group. Postoperative drainage and blood transfusion requirements were similar between the groups. Mechanical ventilation times (6.1 ± 2.2 vs. 8.0 ± 4.4 h, p = .003) and intensive care unit stay (20.4 ± 1.6 vs. 29.4 ± 3.7, p = .027) were shorter in the obesity group. Other postoperative outcomes of infection, atrial fibrillation, hospital stay duration, and readmission rates were similar between the groups.

CONCLUSION

Robotic mitral surgery is safe to perform in obese patients. Obesity should not be a contraindication for robotic mitral surgery as obese patients have outcomes similar to nonobese patients despite increased challenges and risk-factors.

Patient-Tailored Aortic Valve Replacement

Contemporary surgical and transcatheter aortic valve interventions offer effective therapy for a broad range of patients with severe symptomatic aortic valve disease. Both approaches have seen significant advances in recent years. Guidelines have previously emphasized ‘surgical risk’ in the decision between surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR), although this delineation becomes increasingly obsolete with more evidence on the effectiveness of TAVR in low surgical risk candidates. More importantly, decisions in tailoring aortic valve interventions should be patient-centered, accounting not only for operative risk, but also anatomy, lifetime management and specific co-morbidities. Aspects to be considered in a patient-tailored aortic valve intervention are discussed in this article.

Superior epigastric artery perforator flap for reconstruction of deep sternal wound infection

BACKGROUND

The treatment of deep wound sternal infection requires loco-regional pedicled flaps, usually with muscular flaps. Perforator propeller flaps represent the ultimate progress in the history of reconstructive surgery. We report here our experience with the superior epigastric artery perforator (SEAP) flaps to repair sternal defect.

PATIENTS AND METHODS

Six patients presenting deep sternal wounds infection were treated with SEAP propeller flap, between March 2015 and June 2017. The mean age was 71.5 (range 53-83) years. The mean length and width of the defect were 16.2 × 7 cm (ranging 8-20 × 4-10). An elliptical skin flap pedicled on the SEAP was harvested in the inframammary fold and rotated up to 90° to cover the defect.

RESULTS

All SEAP flaps achieved a successful entire coverage of the defect. The mean size of the skin paddle of the flap was 20.2 × 7.3 cm (ranging 14-27 × 6-9). All flaps were able to provide a complete sternal wound cover. Venous congestion was present in five cases and adequately treated by leech therapy; necrosis was distal in one case, and interesting the entire superficial flap in two cases but with deep tissues remaining viable and able to cover the mediastinum: an infected flap required revision. Satisfyingly, at 2-years postoperative follow-up all-patients were alive with a successful mediastinal cover.

CONCLUSIONS

The SEAP Perforator propeller flap is an alternative to muscle flaps to achieve treatment of deep and large sternal wound infection.

Effect of Acute Stress Glycemic Control and Long-Term Glycemic Control on the Incidence of Post-Operative Infection in Diabetics Undergoing Cardiac Surgery

Objective

Post-operative infection after cardiac surgery causes prolonged hospital stay and increased mortality. In patients with diabetes, peri-operative and pre-operative glycemic control have been associated with increased risk of post-operative infection. Saudi Arabia is the 7th highest country in the world for the prevalence of diabetes. In our surgical population the incidence of diabetes is 77%. We were aware of a high incidence of post-operative infections in our institution. The aim of this work was to assess how peri-operative and pre-operative glycemic control was related to the six-week incidence of post-operative infection.

Method

We retrospectively collected data for 174 adult patients with diabetes undergoing cardiac surgery between January 2017 and June 2019. For group analysis of peri-operative glycemic control, a mean value of ≤10 mmol/l was categorized as optimal control and a mean value of >10 mmol/l as sub-optimal control. The admission glucose value, the maximum glucose value and glycosylated hemoglobin A1c (HbA1c) were separately recorded. Admission HbA1c was used for optimal long-term control group (HbA1c ≤ 7%) and sub-optimal long-term control group (HbA1c > 7%).

Results

Of the 174 patients 60 (34%) developed infection in the six-week post-operative period. No statistically significant difference in infections was seen in the optimal peri-operative control group (n = 24, 14%) compared to sub-optimal peri-operative control group (n = 36, 21%; p = 0.113). However, patients with infection had a significantly higher mean glucose (10.4 mmol/l versus 9.9 mmol/l, p = 0.0316) than no infection.

Grouping according to their HbA1c: well controlled group (41, 24.0%) and poor control group (130, 76.0%) showed no difference in infections. However, patients with lower HbA1c had better glycemic control as measured by: initial glucose (r = 0.52, p=<0.001); mean peri-operative glucose (r = 0.45, p=<0.001); maximum recorded glucose (r = 0.41, p=<0.001).

Conclusion

The majority of our patients presented with sub-optimal long-term glycemic control which we linked to poor stress glycemic control perioperatively. Patients with post-operative infections had higher mean peri-operative blood glucose. With the high incidence of diabetes in Saudi Arabia we have demonstrated the importance of good pre-operative assessment which allows tighter peri-operative glycemic control to reduce post-operative morbidity.

The Characteristics of Postoperative Mediastinitis During the Changing Phases of Cardiac Surgery

BACKGROUND

Mediastinitis is a serious complication of open heart surgery associated with high mortality, considerable health care costs, and prolonged hospital stay. We examined characteristics and incidence of mediastinitis during 29 years when indications and patient material have been in a process of change.

METHODS

This was a retrospective population-based study comprising all mediastinitis patients more than 16 years of age after open heart surgery between 1990 and 2018 from a population of 1.7 million. Patient records of 50 mediastinitis patients from 2004 to 2014 were reviewed and compared with 120 patients from 1990 to 1999.

RESULTS

Annual mediastinitis rate varied 0% to 1.5% with a decreasing trend-from a level exceeding 1.2% to approximately 0.3%-over the study period. In 2004 to 2014 patients with mediastinitis were older, more often smokers, and more often had diabetes mellitus and renal insufficiency than in 1990 to 1999. No difference in length of hospital treatment, antibiotic prophylaxis or treatment, intensive care unit treatment, or mortality was observed between 1990 to 1999 and 2004 to 2014. Coronary artery bypass graft surgery became less common and valve replacement and hybrid operations more common among operations leading to mediastinitis. Staphylococcus aureus increased (from 25% to 56%, p = .005) whereas coagulase-negative staphylococci (46% to 23%, P < .001) and gram-negative bacteria (18% to 12%, P = .033) decreased as causative agents. Surgery for mediastinitis remained similar except introduction of vacuum-assisted closure treatment.

CONCLUSIONS

The rate of mediastinitis decreased during these 29 years. No difference in 30-day mortality in mediastinitis was seen: 0.9% in 1990 to 1999 and 2% in 2004 to 2014.

Pharmacokinetic Model for Cefuroxime Dosing during Cardiac Surgery under Cardiopulmonary Bypass

Cefuroxime (CXM) is an antibiotic recommended for surgical site infection prevention in cardiac surgery. However, the dosing regimens commonly used do not sustain therapeutic concentrations throughout surgery. The aim of this study was to conduct a population analysis of CXM pharmacokinetics (PK), and to propose an optimized dosing regimen. Adult patients undergoing cardiac surgery under cardiopulmonary bypass (CPB) received a 1,500 mg CXM intravenous bolus followed by a 750 mg bolus at CPB priming, then every 2 h thereafter. Model-based PK simulations were used to develop an optimized dosing regimen and evaluate its efficacy in attaining various concentration thresholds, including those recommended in US and European guidelines. In total, 447 CXM measurements were acquired in 50 patients. A two-compartment model best fit the data, with total body weight and creatinine clearance determining interpatient variability in the central and peripheral volumes of distribution, and in elimination clearance, respectively. Using our optimized dosing regimen, different dosing schemes adapted to body weight and renal function were calculated to attain total concentration thresholds ranging from 12 to 96 mg/liter. Our simulations showed that the dosing regimens recommended in US and European guidelines failed to maintain concentrations above 48 mg/liter. Our individualized dosing strategy was capable of ensuring therapeutic CXM concentrations conforming to each target threshold. Our model yielded an optimized CXM dosing regimen adapted to body weight and renal function, and sustaining therapeutic concentrations consistent with each desired threshold. The optimal target concentration and necessary duration of its maintenance in cardiac surgery still remain unclear.

Recent developments in controlling sternal wound infection after cardiac surgery and measures to enhance sternal healing

One of the major risks of cardiac surgery is the occurrence of infection at the sternal wound site. Sternal wound infections are primarily classified into superficial infection and deep sternal wound infection or mediastinitis. A patient is diagnosed with mediastinitis if microorganisms are present in their mediastinal tissue/fluid or with the observation of sternal wound infection during operation and with characteristic symptoms including chest pain, fever, and purulent drainage from the mediastinum. It is usually caused by Staphylococcal organisms in 75.8% of cases and the rest is caused by gram-negative bacteria. Currently, in cardiac surgery, hemostasis is achieved using electrocautery and bone wax, and the sternum is closed using wire cerclage. Several studies show that bone wax can act as a nidus for initiation of infection and the oozing blood and hematoma at the site can promote the growth of infectious organisms. Many research groups have developed different types of biomaterials and reported on the prevention of infection and healing of the sternum. These materials are reported to have both positive and negative effects. In this review, we highlight the current clinical practices undertaken to prevent infection and bleeding as well as research progress in this field and their outcomes in controlling bleeding, infection, and enhancing sternal healing.

Reduction in the infection rate of cranioplasty with a tailored antibiotic prophylaxis: a nonrandomized study

BACKGROUND

Cranioplasty carries a high risk of surgical site infections (SSIs) for a scheduled procedure, particularly with antibiotic-resistant bacteria.

METHODS

The goal of this retrospective study was to measure the effect of tailored antibiotic prophylaxis on SSIs resulting from cranioplasties. The authors collected a prospective database of cranioplasties from 2009 to 2018. Risk factors for SSI were registered, as well as infection occurring during the first year postoperatively. A new protocol was initiated in 2016 consisting of antibiotic prophylaxis tailored to the colonizing flora of the skin of the scalp and decolonization of patients who were nasal carriers of methicillin-resistant S. aureus (MRSA); infection rates were compared.

RESULTS

One hundred nine cranioplasties were identified, 64 in the old protocol and 45 in the new protocol. Of the 109 cranioplasties, 16 (14.7%) suffered an infection, 14 (21.9%) in the old protocol group and 2 (4.4%) in the new protocol group (OR for the new protocol 0.166, 95% CI 0.036-0.772). Multiple surgeries (OR 3.44), Barthel ≤ 70 (OR 3.53), and previous infection (OR 3.9) were risk factors for SSI. Of the bacteria identified in the skin of the scalp, 22.2% were resistant to routine prophylaxis (cefazoline). Only one patient was identified as a nasal carrier of MRSA and was decolonized.

CONCLUSIONS

A high percentage of bacteria resistant to routine prophylaxis (cefazoline) was identified in the skin of these patients' scalps. The use of tailored antibiotic prophylaxis reduced significantly the infection rate in this particular set of patients.

Imaging features and differential diagnoses of non-neoplastic diffuse mediastinal diseases

Acute or chronic non-neoplastic diffuse mediastinal diseases have multiple causes, degrees of severity, and a wide range of management. Some situations require emergency care while others do not need specific treatment. Although the diagnosis may be suspected on chest X-ray, it is mainly based on CT. A delayed recognition is not uncommonly observed. Some findings may prompt the radiologist to look for specific associated injuries or lesions.

This pictorial review will successively describe the various non-neoplastic causes of diffuse mediastinal diseases with their typical findings and major differentials.

First, pneumomediastinum that can be provoked by extra- or intra-thoracic triggers requires the knowledge of patient’s history or recent occurrences. Absence of any usual etiological factor should raise suspicion of cocaine inhalation in young individuals.

Next, acute mediastinitis may be related to post-operative complications, esophageal perforation, or contiguous spread of odontogenic or retropharyngeal infections. The former diagnosis is not an easy task in the early stage, owing to the similarities of imaging findings with those of normal post-operative appearance during the first 2–3 weeks.

Finally, fibrosing mediastinitis that is linked to an excessive fibrotic reaction in the mediastinum with variable compromise of mediastinal structures, in particular vascular and airway ones. Differential diagnosis includes tumoral and inflammatory infiltrations of the mediastinum.

Topical rifampicin for prevention of deep sternal wound infections in patients undergoing coronary artery bypass grafting

Deep sternal wound infections (DSWI), although an infrequent complication, significantly impair postoperative outcomes after coronary artery bypass grafting (CABG) surgery. Among several preventive strategies, topical antibiotic therapy immediately before sternal closure has been strongly advocated. In this retrospective analysis, the incidence of DSWI in 517 patients undergoing isolated CABG and receiving rifampicin irrigation of mediastinum, sternum and suprasternal tissues was compared to an historical consecutive cohort of 448 patients. To account for the inherent selection bias, a 1:1 propensity matched analysis was performed. Patients receiving topical rifampicin experienced significantly less occurrence of postoperative DSWI (0.2% vs 2.5%, p = 0.0016 in the unmatched analysis; 0.3% vs 2.1%, p = 0.0391 in the matched analysis). Intensive care unit stay, hospital stay, and operative mortality were similar between groups. This study shows that topical rifampicin in combination with commonly prescribed preventative strategies significantly reduces the incidence of DSWI to less than 0.3% in unselected patients undergoing a full median sternotomy for CABG. Further studies, including a larger number of patients and with a randomization design, would establish the potential preventative role of topical rifampicin in reducing the occurrence of DSWI.

Right Ventricle Rupture After Open Heart Surgery

The potential complications of cardiac surgery with sternotomy include mediastinitis and major bleeding, events that are infrequent but carry high mortality.We report a unique complication of median sternotomy. A 71-year-old man underwent coronary artery bypass grafting complicated by sternal dehiscence on postoperative day 7. One week after discharge, he presented with purulent drainage from the sternal wound bed and was diagnosed as having mediastinitis. Irrigation, debridement, and sternal reconstruction were performed. Two days later, bleeding was observed in the wound, and during surgical exploration, a tear in the right ventricle was discovered, and the patient exsanguinated and died. Autopsy findings included focal adhesions connecting the posterior sternum to the right ventricle wall, as well as microscopic evidence of focally extensive fatty infiltration along the rupture margin of the myocardium.Pertinent aspects of the case are reviewed, with particular attention to the possible microbial etiology of mediastinal infection and most likely mechanisms of injury contributing to the fatal right ventricular rupture.

Sequential antimicrobial therapy in mediastinitis after cardiac surgery: An observational study of 81 cases

INTRODUCTION

Mediastinitis is an infrequent but serious complication of cardiac surgery. Antimicrobial treatment guidelines are not well established. The aim was to describe the efficacy of sequential intravenous to oral therapy in selected post-surgical mediastinitis patients.

METHODS

A retrospective observational study including cases of mediastinitis after cardiac surgery, defined according to CDC criteria, at a third-level university hospital between January 2002 and December 2016. Sequential antimicrobial therapy was proposed in clinically stable patients. Rates of cure, relapse, and hospital stay were compared between patients who received sequential intravenous to oral therapy and those who received therapy exclusively by the intravenous route.

RESULTS

Eighty-one cases were included. Sequential intravenous to oral therapy was performed in 48 (59.3%) patients on median day 15. No differences in baseline characteristics or causal microorganisms were found between the two cohorts. The average duration of antibiotic therapy was 41.2±10.09 days. The most commonly used drugs in sequential therapy were quinolones in 31 (64.6%) cases and rifampicin, always in association with another antibiotic, in 25 (52.1%). Hospital stay was shorter in the sequential therapy group (57.57±34.03 vs. 84.35±45.67; P=0.007). Cure was achieved in 77 (92.8%) patients. Overall in-hospital mortality was less frequent in the group that received sequential therapy (2.1% vs. 15.2%; P=0.039). There were no differences in relapse between the two cohorts (4.2% vs 9.1%; P=0.366).

CONCLUSION

Sequential antimicrobial treatment in selected patients with post-surgical mediastinitis may be as effective as exclusively intravenous treatment, reducing risks, hospital stay and associated costs.

Sternal Wound Reconstruction Made Simple

Sternal wounds and associated infections represent a complex reconstructive problem in a highly morbid patient population. Through strict adherence to excellent plastic surgical principles, this process can be simplified, allowing safe and effective wound closure. Emphasis is placed on thorough debridement, hardware removal, obtaining adequate tissue cultures, and finally, appropriate flap closure. In most cases, pectoralis major myocutaneous advancement flaps provide excellent coverage while eliminating dead space and providing sternal compression. Secondary flap options, such as the omental flap or rectus abdominis muscle, may occasionally be necessary. This article will provide an overview and simplified approach to sternal wound reconstruction.

Concordance between superficial swab and deep sampling in post-sternotomy mediastinitis: Single center experience

OBJECTIVES

Deep sampling (DS) is the gold standard for microbiological diagnosis of post-sternotomy mediastinitis (PSM), however superficial swab (SS) are frequently performed in some centers and antibiotherapy initiated base on their results. We analysed the concordance between superficial swab and deep sampling in PSM.

MATERIALS AND METHODS

We analysed retrospectively patients with a PSM between 2010 and 2014 at Saint-Luc University hospital (Belgium). We considered that there was a concordance between SS and DS when the same microorganism was found in the two sampling method in each patient. Patients were stratified in six groups according to microbiology results as Staphylococcus Aureus (SA) sensitive or resistant, coagulase negative Staphylococcus (CoNS), Gram negative bacilli (GNB), other Gram positive bacteria (GPB) and fungi.

RESULTS

Thirty-six patients were included. Twenty-five men (69%) and a mean age of 66 years old. The overall concordance between SS and DS was 57%. SA and GNB showed high concordance (100% and 85.7% respectively). For the other groups the concordance was low. The sensitivity and specificity of SS was 97% and 33% respectively. The PPV and NPV of superficial swab was 96% and 50% respectively.

CONCLUSION

Microbiological results from SS, even with flocked swabs, except for SA and GNB have low concordance with those obtained from deep sampling. Our data confirm that in PSM, deep sampling is the gold standard for microbiological assessment.

Cellulose-Derived Absorbable Hemostatic Product as a Risk Factor for Mediastinitis after Cardiac Surgery

Background: We describe the management and control of an outbreak of mediastinitis in a cardiac surgery department. Method: We performed a retrospective cohort study of 87 patients who underwent coronary artery bypass grafting (CABG), valve replacement, or both during a five-month period with a higher than normal number of cases of post-operative mediastinitis. In addition to medical records review, a survey was conducted among surgeons to estimate the frequency of cellulose-derived absorbable hemostatic (CDAH) use. Results: Eleven patients (12.5%) developed mediastinitis during the period. None of them died, and the course of the infections was benign. No differences were found between the infected and non-infected patients regarding clinical or demographic characteristics. The rate of infection by surgeon ranged from 0 to 21.4%. (p = 0.38). We found a significant linear relation between the frequency of CDAH use and the risk of infection, from 3.3% to 22.6% (p = 0.024). Cultures of unused CDAHs were negative. Cessation of product use led to no new cases for the following year and to a mediastinitis rate <1% for the following 24 months. Conclusion: We identified a cluster of undesired clinical outcomes compatible with mediastinitis that added morbidity and associated cost, but not deaths, related to the use of CDAH as a hemostatic. These data suggest keeping the use of CDAH in cardiothoracic surgery to a minimum.