Abstract

Background: This study aims to compare the effectiveness of negative-pressure wound therapy (NPWT) compared to conventional methods for the treatment of mediastinitis following coronary artery bypass grafting.

Methods: Between January 2010 and January 2023, a total of 87 patients (47 males, 40 females; mean age: 62.0±10.2 years; range, 35 to 80 years) who developed mediastinitis following sternotomy were retrospectively analyzed. The patients were divided into two groups: those treated with conventional methods (n=39) from January 2010 to February 2015 and those treated with NPWT (n=48) from March 2015 to January 2023. Clinical outcomes, including treatment duration, infection resolution time, hospital stay, and mortality rate, were recorded.

Results: The NPWT group had significantly shorter treatment durations (20.1±4.0 days) than the conventional group (58.6±17.1 days, p<0.001). The time to achieve negative cultures was also significantly reduced in the NPWT group (15.3±3.6 days) compared to the conventional group (36.7±8.1 days, p<0.001). The length of hospital stay was shorter in the NPWT group (34.3±12.8 days) compared to the conventional group (88.0±21.1 days, p<0.001). The NPWT group had a lower hospital mortality rate (4.2%) than the conventional group (17.9%, p=0.049).

Conclusion: The NPWT demonstrated superior efficacy in managing postoperative mediastinitis compared to conventional methods, highlighting its potential as a preferred treatment option for this serious complication.

Mediastinitis is a potentially severe and lifethreatening infection which may arise following cardiac interventions, particularly isolated coronary artery bypass grafting (CABG).[1] This condition involves infection and inflammation within the mediastinum, which is the central area of the thoracic cavity, and can result in serious outcomes if not properly treated. Although notable progress has been made in surgical methods and postoperative management, mediastinitis continues to be a major concern. Its incidence varies across patient populations and institutional practices.[2]

Managing mediastinitis typically requires a multidisciplinary approach that includes surgical removal of the infected tissue, administration of antibiotics, and various wound care methods.[3] Conventional treatment methods, including open wound packing and secondary closure, have been the standard approaches for many years. However, these methods are often associated with prolonged hospital stay, increased morbidity, and a significant risk of recurrent infections.[4] As a result, there has been growing interest in alternative treatment modalities that may offer improved outcomes for patients with this severe complication.[5]

In recent years, negative-pressure wound therapy (NPWT) has emerged as a promising alternative for the management of mediastinitis following CABG.[6] This therapy involves the application of a controlled vacuum to the wound, which promotes healing by removing exudates, reducing edema, and enhancing tissue perfusion. Numerous studies have suggested that NPWT may reduce the length of hospital stay, lower the risk of infection recurrence, and improve overall wound healing outcomes compared with conventional methods.[7] Despite these potential benefits, the use of NPWT remains a subject of ongoing debate, particularly regarding its cost-effectiveness and long-term outcomes.

In the present study, we hypothesized that NPWT could provide superior clinical outcomes compared to conventional treatment methods in the management of post-sternotomy mediastinitis (PSM) following isolated CABG, including shorter treatment duration, reduced infection recurrence, and decreased hospital stay. We, therefore, aimed to assess the effectiveness of NPWT compared to standard care approaches in treating mediastinitis after isolated CABG.

Methods

This single-center, retrospective study was conducted at Bakırköy Dr. Sadi Konuk Training and Research Hospital, Department of Cardiovascular Surgery between January 2010 and January 2023. Mediastinitis cases who developed following sternotomy were screened. During the first period (January 2010 and February 2015), all PSM patients were treated using conventional methods, while in the second period (March 2015 and January 2023), patients were treated using the NPWT vacuum-assisted closure (VAC) technique. The study group consisted of patients who underwent isolated CABG and were diagnosed with mediastinitis following sternotomy. Patients were excluded from the study if they underwent cardiac surgery for indications other than coronary artery disease, such as aortic, mitral, or atrial septal defect surgery. Additional exclusion criteria included a history of minimally invasive cardiac surgery, previous thoracic surgery, redo cardiac surgery, the presence of a non-microbial sternal wound, or cases that were performed as emergency procedures. Finally, a total of 87 patients (47 males, 40 females; mean age: 62.0±10.2 years; range, 35 to 80 years) were included in the study, of whom 39 received conventional treatment and 48 were treated with VAC therapy (Figure 1). No patients were lost to follow-up and there were no missing data for the variables analyzed. Written informed consent was obtained from each patient. The study protocol was approved by the Bakırköy Dr. Sadi Konuk Training and Research Hospital Clinical Research Ethics Committee (Date: 04.03.2024, No: 2024-04-06). The study was conducted in accordance with the principles of the Declaration of Helsinki.

Figure 1. Study flowchart.
CABG: Coronary artery bypass grafting; NPWT: Negative-pressure wound therapy.

As of March 2015, based on the joint decision of our institution's Infection Control Committee and the Cardiac Surgery Council, VAC therapy was adopted as standard practice. This decision was supported by increasing evidence in the national and international literature indicating faster granulation tissue formation, higher success rates in infection control, and shorter recovery times compared to conventional treatment. Considering the known risks of VAC-related complications, particularly bleeding from the right ventricle and coronary anastomoses, the negative pressure level was initially kept low and gradually increased after adequate granulation tissue formation was achieved.

Surgical environment and humidity control
During surgery, relative humidity (RH) levels in the operating rooms were maintained between 20% and 60%, as specified by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE).[8] This standard was implemented to minimize the risk of infection in the surgical environment, and humidity conditions were ensured for all surgical procedures conducted in the study.

Prophylactic and postoperative antibiotic use
All patients received standard prophylactic antibiotic treatment with cefazolin sodium administered four times daily on the day of surgery and on postoperative Days 1 and 2. In patients diagnosed with mediastinitis, if Gram-positive microorganisms were detected in the tissue cultures, intravenous vancomycin hydrochloride was initiated twice daily. If Gram-negative microorganisms were identified, a combination of piperacillin-tazobactam was administered three times daily. Antibiotic therapy was usually continued, until tissue culture results were obtained and adjusted according to bacterial susceptibility based on the results.

Surgical intervention and wound management
Upon identification of sternal infection, wires were extracted under sterile conditions, and the sternum was completely exposed. Both groups underwent extensive debridement of the sternal and surrounding tissue. For those receiving standard treatment, the wound was cleansed using povidone-iodine and saline, and the non-occlusive dressings were changed multiple times per day. Once three sequential negative cultures were confirmed and adequate granulation tissue developed, the sternum was re-approximated, and fixation was re-established in suitable cases.

For patients in the VAC group, debridement was performed following the reopening of the surgical site and removal of sternal wires under sterile conditions, and a VAC system was implemented using a polyurethane dressing and a dedicated suction device. The sponge component was inserted beneath the sternum, with extensions placed between the bony margins and subcutaneous tissues. The wound area was sealed using a semi-permeable adhesive layer attached to a vacuum unit, delivering a continuous negative pressure ranging from -75 to -150 mmHg. Dressings were renewed every 72 h. For control cultures, tissue samples were obtained at regular intervals every three days following the initial diagnosis. In addition, if the patient's wound exhibited foul-smelling purulent discharge or other clinical signs of infection, supplementary control cultures were collected. In this way, microbiological monitoring was ensured both through scheduled sampling and through additional sampling guided by clinical findings. Three patients had a closed sternum following surgical revision. This was due to the complete disruption of sternal integrity by mediastinitis and the absence of sufficient viable bone tissue for closure. None of the patients underwent a closed sternal or drain irrigation technique. In the early period, when the VAC system was not yet available, patients were managed using an open-chest approach. After the introduction of the VAC system, it was applied in all patients with mediastinitis.

Diagnosis of mediastinitis
Postoperative mediastinitis was diagnosed either during the initial hospitalization period or within the early postoperative weeks following discharge upon readmission with clinical signs such as sternal dehiscence, fever, and purulent discharge. Mediastinitis was diagnosed according to the Centers for Disease Control and Prevention/National Healthcare Safety Network (CDC/NHSN) criteria based on microbiological, anatomical, and clinical findings.[9] The detection of microorganisms in mediastinal tissue or fluid samples, confirmed by culture or non-culture microbiological methods, was the primary diagnostic criterion. Histopathological examination of the tissues obtained during surgery further supported this diagnosis. Clinical signs included fever (>38.0°C), thoracic discomfort, sternal instability, purulent discharge, or radiological evidence of mediastinal enlargement. All cases met the CDC/NHSN definition of mediastinitis, ensuring diagnostic consistency and data reliability. For all patients, microbiological samples were obtained intraoperatively from the mediastinal tissue at the time of surgical debridement, prior to the initiation of targeted antibiotic therapy. This protocol was uniformly applied to both the conventional treatment and NPWT groups to ensure comparability.

Statistical analysis
Statistical analysis was performed using the IBM SPSS for Windows version 27.0 software (IBM Corp., Armonk, NY, USA). The normality of the data distribution was assessed using the Kolmogorov-Smirnov test. Descriptive data were expressed in mean ± standard deviation (SD), median (min-max) or number and frequency, where applicable. For parameters that followed a normal distribution, comparisons between the NPWT and conventional treatment groups were performed using an independent sample t-test. For non-normally distributed parameters, the Mann-Whitney U test was used. Categorical data were analyzed using the Fisher exact test. A p value of <0.05 was considered statistically significant.

Results

Most patients were smokers (75.9%) and had a high prevalence of comorbidities including hypertension (62.1%), diabetes mellitus (58.6%), and hypercholesterolemia (66.7%). The mean body mass index (BMI) was 28.9±5.0 kg/m². According to the EuroSCORE risk assessment, 70.1% of the patients were classified as high-risk, with no patients in the low-risk category. At the time of mediastinitis diagnosis, the mean white blood cell (WBC) count was 18.5±2.8×10³/µL, hemoglobin was 10.4±1.6 g/dL, hematocrit was 31.3±4.9%, and C-reactive protein (CRP) level was 105.1±23.6 mg/L. These values improved by discharge, with WBC decreasing to 5.5±0.8×10³/µL and CRP to 21.1±5.1 mg/L, while hemoglobin and hematocrit increased modestly. The mean ejection fraction was 44.4±7.1% at the time of diagnosis. The mean cross-clamp time was 100.2±13.1 min, and the mean cardiopulmonary bypass time was 123.6±17.4 min.

The use of the internal mammary artery (IMA) varied, with the left IMA being used in 76 patients (87.4%), the right IMA in two (2.3%) patients, and bilateral use in nine (10.3%) patients. According to the PSM El-Oakley classification, type 3A was the most common, observed in 35 (40.2%) patients, followed by type 3B in 24 (27.6%). Type 2 classification was observed in 10 (11.5%) patients, while type 1 was identified in seven (8.0%) patients. Less common were type 4A in five (5.7%) patients, type 5 in four (4.6%) patients, and type 4B in two (2.3%) patients. Regarding additional procedures for PSM, 37 (42.5%) patients underwent re-steel wire closure, 27 (31.0%) patients had plaque closure, and 13 (14.9%) patients required leg graft closure. Pectoral muscle flap procedures were performed in nine (10.3%) patients, and omentoplasty was performed in one (1.1%) patient. Hospital mortality was associated with pneumonia in five (5.7%) patients, wound infection in three (3.4%) patients, and intracranial hemorrhage in one (1.1%) patient (Table 1).

Table 1. Internal mammary artery use, El-Oakley classification, additional procedures, and in-hospital causes of death

The mean time to diagnosis of postoperative mediastinitis was 11.7±2.7 days. The mean duration of treatment for mediastinitis was 37.4±22.6 days. The time from diagnosis to obtaining a negative culture was 24.9±12.3 days. Patients had a mean intensive care unit (ICU) stay of 18.7±27.9 days, while the overall mean hospitalization duration was 58.4±30.6 days (Table 2).

Table 2. Care-pathway timing measures: time to diagnosis, treatment duration, time to negative culture, ICU stay, and total length of stay

No significant differences were found between the conventional treatment group (n=39) and NPWT group (n=48) in terms of demographic characteristics and comorbidities. The mean age, BMI, sex distribution, smoking status, and the prevalence of hypertension, diabetes mellitus, chronic obstructive pulmonary disease (COPD), and pulmonary arterial hypertension were comparable between the groups. At the time of diagnosis, WBC, hemoglobin, hematocrit, CRP, and ejection fraction values did not differ significantly between the two groups. However, at the time of discharge, the WBC (p=0.031) and CRP (p<0.001) levels were significantly lower in the NPWT group. No differences were observed in hemoglobin, hematocrit, ejection fraction, or operating room RH values (Table 3).

Table 3. Conventional vs. NPWT: hematological parameters at diagnosis and discharge

The NPWT group required significantly less transfusion volume, with a mean of 118.7±128.7 mL compared to 188.7±160.4 mL in the conventional group (p=0.025). Additionally, the duration of mediastinitis treatment was notably shorter in the NPWT group, averaging 20.1±4.0 days versus 58.6±17.1 days in the conventional group (p<0.001). The time from diagnosis to negative culture was also significantly reduced in the NPWT group (15.3±3.6 days) compared to the conventional group (36.7±8.1 days, p<0.001). The mean ICU duration was shorter in the NPWT group, with a mean of 8.3±8.3 days compared to 31.5±37.0 days in the conventional group (p<0.001). Hospitalization duration was significantly lower in the NPWT group with a mean duration of 34.3±12.8 days compared to 88.0±21.1 days in the conventional group (p<0.001) (Table 4).

Table 4. Conventional vs. NPWT: intraoperative and postoperative outcomes

Patients in the NPWT group demonstrated a notably lower rate of in-hospital mortality, with a survival rate of 95.8%, compared to 82.1% among those receiving standard treatment (p=0.049). No significant differences were identified regarding the use of the IMA or the PSM El-Oakley classification between the cohorts. However, a greater proportion of individuals in the NPWT arm belonged to the type 3A category (45.8%) than in the conventional group (33.3%). Furthermore, EuroSCORE evaluations, microbial profiles in PSM, and additional interventions revealed no statistically significant differences between the groups (Table 5).

Table 5. Conventional vs. NPWT: EuroSCORE risk profile, microbiology, additional procedures, and in-hospital mortality

In two patients, subcutaneous bleeding that occurred during sternal revision under NPWT led to detachment of the adhesive drapes from the skin and thrombus formation within the VAC sponge. Consequently, the VAC system failed to function, and was replaced. No other major complications were noted.

In the multivariate regression analyses, NPWT was independently associated with significantly shorter durations across all time-related outcomes. Specifically, NPWT reduced treatment duration (incidence rate ratio [IRR]: 0.35, 95% confidence interval [CI]: 0.23-0.54; p<0.001), length of hospital stay (IRR: 0.39, 95% CI: 0.26-0.61; p<0.001), ICU stay (IRR: 0.38, 95% CI: 0.24-0.59; p<0.001), and the time from diagnosis to negative culture (IRR: 0.42, 95% CI: 0.27-0.65; p<0.001). All these associations remained statistically significant after Benjamini-Hochberg false discovery rate adjustment. In-hospital mortality showed a trend in favor of NPWT (adjusted odds ratio [aOR]: 0.38, 95% CI: 0.06-2.58), although this result did not reach statistical significance (p=0.32), likely due to the limited number of events (Table 6).

Table 6. Multivariable regression analyses of clinical outcomes comparing NPWT and conventional treatment

Discussion

In the present study, we evaluated the effectiveness of NPWT for the treatment of PSM following CABG. Our study results showed that NPWT provided significantly better outcomes than conventional treatment in managing postoperative mediastinitis. Patients in the NPWT group experienced faster recovery, shorter treatment duration, quicker resolution of infection, and reduced hospital stay. Additionally, the NPWT group had a lower in-hospital mortality rate, reinforcing the effectiveness of NPWT as a superior treatment modality in this clinical context. The use of the IMA and pathogen distribution were comparable between the groups; however, the effect of NPWT on reducing complications was evident.

Infection of the sternotomy site can be a serious and sometimes life-threatening issue after cardiac surgical procedures. Literature data indicate that postoperative mediastinitis occurs in approximately 0.4 to 5% of cases.[10,11] Several previously reported known r isk f actors, s uch a s d iabetes m ellitus (58.6%), COPD (41.4%), renal impairment (40.2%), and high blood pressure (62.1%), were also observed in our cohort. Conventional treatment approaches have been used for a long time in these patients, while several authors have reported mortality rates ranging from 10 to 47%.[12,13] Vacuum-assisted closure is a relatively recent technique which utilizes an open-cell foam dressing sealed with an adhesive film. A connected vacuum unit applies either a continuous or intermittent negative pressure. While drawing out the wound exudate, the system concurrently stabilizes the chest wall and isolates the wound site. The VAC treatment promotes the development of granulation tissue by enhancing perfusion to nearby tissues.[14] According to a prior systematic analysis, NPWT in PSM cases was linked to improved clinical outcomes compared with conventional wound care methods, specifically shorter hospital stays, reduced reinfection rates, and decreased early mortality.[15] In our analysis, the overall treatment time for PSM, including the interval from diagnosis to confirmed negative cultures, hospital stay duration, and in-hospital mortality, were found to be significantly lower in the VAC-treated group than in the standard care cohort. Moreover, reconstructive surgery with vascularized flaps represents an additional therapeutic option for PSM, particularly in cases involving substantial soft-tissue defects. Flap reconstruction may be the only viable method in cases of extensive soft tissue damage. The use of omental flaps for sternal repair was first reported by Lee et al.[16] in 1976, followed by Jurkiewicz et al.[17] who introduced pectoral flap applications for this purpose in 1980. In our cohort, flap-based interventions were performed in nine individuals (10.3%). In our study, the rates of complex surgical procedures were similar between the NPWT and conventional treatment groups. However, the shorter treatment duration, lower inflammatory marker levels, and reduced need for blood transfusion observed in the NPWT group may have facilitated the completion of the surgical repair process with fewer additional invasive interventions.

The outcomes of our study are in concordance with those reported by Akbayrak and Tekumit,[18] supporting the notion that NPWT markedly enhances clinical outcomes in cases of postoperative mediastinitis compared to standard care methods. Both investigations indicated that NPWT contributes to shorter treatment times, faster achievement of negative cultures, and reduced hospitalization duration. Such parallel results reinforce the superior effectiveness of NPWT in managing postoperative mediastinitis, positioning it as a favorable therapeutic option in routine medical practice.[12] Similarly, our data align with the findings of Akyıldız and Ulular,[19] who reported that NPWT played a crucial role in lowering the likelihood of postoperative mediastinitis, particularly following CABG. Their research further emphasizes the value of initiating treatment promptly and applying NPWT efficiently, particularly among high-risk populations, such as individuals with obesity or diabetes. These conclusions underscore that NPWT is valuable not only for averting serious postoperative complications, but also for boosting overall recovery in cardiac surgery patients. This highlights the necessity of employing proactive infection prevention tactics and individualized treatment plans to improve healing and reduce the risk of complications in susceptible individuals. In the literature, one of the most well-known complications of NPWT[20] and coronary saphenous vein bleeding was not observed in our study. This absence is attributed to the initial application of vacuum pressure at a low level, followed by a gradual increase after adequate granulation tissue formation was achieved.

Gram-positive microorganisms are the leading pathogens identified in cases of mediastinitis, with Gram-negative species occurring less frequently.[21] While some studies have reported Staphylococcus aureus as the most common pathogen, others have reported coagulase-negative staphylococci (CNS) as the most prevalent causative agent.[22,23] Our study corroborates these findings, as we observed that gram-positive bacteria were the most prevalent pathogens in patients with mediastinitis, followed by Gram-negative bacteria. Specifically, Staphylococcus aureus a nd CNS were the predominant pathogens identified, consistent with the patterns reported in the literature. These results further emphasize the importance of targeted antimicrobial therapy for the management of postoperative mediastinitis.

Our finding that NPWT may reduce the requirement for advanced reconstructive procedures aligns with the recent evidence. In a retrospective cohort, Rashed et al.[24] reported that patients receiving incisional NPWT after initial reconstructions for PSM had significantly lower rates of reconstructive failure, defined as the need for additional surgical intervention, than those managed with standard drains alone (10% vs. 4 5.5%; p =0.072), a long w ith s horter d rainage duration and hospital stay. This suggests that NPWT may enhance wound obliteration and reduce dead space, thereby diminishing the dependence on pectoral flaps or omental reconstruction. Supporting this, a systematic review by Liu et al.[25] on deep sternal wound infection (DSWI) demonstrated that NPWT use was associated with significantly reduced reinfection rates (RR: 0.43, 95% CI: 0.25- 0.74; p=0.002) and shorter hospital and ICU stays compared to conventional therapy. Together, these data reinforce our observations and suggest the role of NPWT as a bridge that may limit the need for extensive reconstruction efforts in mediastinitis management.

Although our study did not directly assess cost-effectiveness or long-term outcomes beyond in-hospital follow-up, emerging literature suggests that these are vital considerations. For instance, Othman[26] reported that NPWT can expedite chronic wound healing, potentially reducing overall treatment costs and enhancing patient satisfaction. However, a recent economic evaluation by Saramago et al.[27] found that for open surgical wound healing by secondary intention, NPWT was associated with higher costs and only marginally higher quality-adjusted life years (QALYs), with a probability of cost-effectiveness below 30%. Similarly, in a cost-comparison analysis, Älgå et al.[28] found NPWT to cost approximately US $142 more per patient treated than standard care, noting that these results remained robust across sensitivity analyses. These findings underscore the need for future studies on mediastinitis that include longterm and economic endpoints to fully understand the value of NPWT in this setting.

Nonetheless, this study has several limitations. First, its retrospective nature raises the potential for selection bias due to reliance on previously recorded data, which may not fully reflect all pertinent clinical factors. Second, as the study was performed at a single institution, the applicability of the results to other clinical environments may be constrained. Third, the modest number of participants, particularly in subgroup evaluations, could have lowered the ability of the study to detect significant differences. Furthermore, although attempts were made to address the confounding variables, it is still possible that some unmeasured factors influenced the results. In addition, the relatively high cost of NPWT, requirement for experienced personnel, and possible limitations in equipment availability in certain centers should also be acknowledged as potential barriers to its widespread use. Also, this study did not include long-term follow-up data such as recurrence rates or patient-reported quality of life outcomes, which could provide further insight into the sustained impact of NPWT in mediastinitis management. To strengthen these findings, future research should adopt a prospective multicenter approach with expanded sample sizes, enabling a more robust and comprehensive assessment of the role of NPWT in the treatment of postoperative mediastinitis.

In conclusion, through an in-depth evaluation of both strategies, this study aspires to offer meaningful contributions to improving mediastinitis treatment practices in cardiac surgery settings. negative-pressure wound therapy has demonstrated significant advantages over conventional treatment methods for the management of mediastinitis following coronary artery bypass grafting. Patients treated with negative-pressure wound therapy showed faster recovery, reduced infection resolution times, shorter hospital stays, and lower hospital mortality rates. These findings suggest that negative-pressure wound therapy should be considered the preferred treatment modality for postoperative mediastinitis, particularly in high-risk patients. Future research should focus on further validating these results through larger multi-center prospective studies to reinforce the clinical guidelines for the management of this serious complication. Since March 2015, negative-pressure wound therapy has been implemented as the standard protocol in our clinic for the treatment of poststernotomy mediastinitis and is preferred in all eligible patients. This approach continues to be used currently, and we aimed to expand our series to newly diagnosed cases.

Data Sharing Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.

Author Contributions: Idea/concept, design, literature review: H.T.; Control/supervision: Y.K.; Data collection and/ or processing: G.T.; Analysis and/or interpretation, writing the article: A.A.K.; References and fundings, materials: S.T.

Conflict of Interest: The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Funding: The authors received no financial support for the research and/or authorship of this article.

References

1) Vettath MP, Ravisankar M, Kopjar T, Kannan AV, Gangadharan N. Off-pump coronary artery bypass grafting improves early clinical outcomes including operative mortality. Heart Surg Forum 2018;21:E151-7. doi: 10.1532/ hsf.2007.

2) Badawy MA, Shammari FA, Aleinati T, Eldin MS, Tarazi R, Alfadli J. Deep sternal wound infection after coronary artery bypass: How to manage? Asian Cardiovasc Thorac Ann 2014;22:649-54. doi: 10.1177/0218492314536106.

3) Pastene B, Cassir N, Tankel J, Einav S, Fournier PE, Thomas P, et al. Mediastinitis in the intensive care unit patient: A narrative review. Clin Microbiol Infect 2020;26:26-34. doi:10.1016/j.cmi.2019.07.005.

4) Nakamori Y, Fujimi S, Ogura H, Kuwagata Y, Tanaka H, Shimazu T, et al. Conventional open surgery versus percutaneous catheter drainage in the treatment of cervical necrotizing fasciitis and descending necrotizing mediastinitis. AJR Am J Roentgenol 2004;182:1443-9. doi:10.2214/ajr.182.6.1821443.

5) Sjögren J, Malmsjö M, Gustafsson R, Ingemansson R. Poststernotomy mediastinitis: A review of conventional surgical treatments, vacuum-assisted closure therapy and presentation of the Lund University Hospital mediastinitis algorithm. Eur J Cardiothorac Surg 2006;30:898-905. doi:10.1016/j.ejcts.2006.09.020.

6) Pagotto VPF, Gallafrio ST, Carneiro IC, Gemperli R, Jatene FB. Treatment and chest reconstruction for mediastinitis following sternotomy for cardiac surgery at the heart institute of the University of São Paulo Medical School. Braz J Cardiovasc Surg 2021;36:565-70. doi: 10.21470/1678-9741-2020-0117.

7) Repossini A, Dossena T, D'Alonzo M, Stara A, Rosati F, Muneretto C, et al. Surgical treatment of mediastinitis: The vertical bolstered Donati stitch. Multimed Man Cardiothorac Surg 2021;2021. doi: 10.1510/mmcts.2021.003.

8) ANSI/ASHRAE/ASHE. Standard 170-2013 ventilation of health care facilities. Atlanta, GA: ASHRAE; 2013.

9) Horan TC, Andrus M, Dudeck MA. CDC/NHSN surveillance definition of health care-associated infection and criteria for specific types of infections in the acute care setting. Am J Infect Control 2008;36:309-32. doi: 10.1016/j.ajic.2008.03.002.

10) El Oakley RM, Wright JE. Postoperative mediastinitis: Classification and management. Ann Thorac Surg 1996;61:1030-6. doi: 10.1016/0003-4975(95)01035-1.

11) Risnes I, Abdelnoor M, Almdahl SM, Svennevig JL. Mediastinitis after coronary artery bypass grafting risk factors and long-term survival. Ann Thorac Surg 2010;89:1502-9. doi: 10.1016/j.athoracsur.2010.02.038.

12) Sjögren J, Gustafsson R, Nilsson J, Malmsjö M, Ingemansson R. Clinical outcome after poststernotomy mediastinitis: Vacuum-assisted closure versus conventional treatment. Ann Thorac Surg 2005;79:2049-55. doi: 10.1016/j. athoracsur.2004.12.048.

13) Sarr MG, Gott VL, Townsend TR. Mediastinal infection after cardiac surgery. Ann Thorac Surg 1984;38:415-23. doi:10.1016/s0003-4975(10)62300-4.

14) Morykwas MJ, Argenta LC, Shelton-Brown EI, McGuirt W. Vacuum-assisted closure: A new method for wound control and treatment: animal studies and basic foundation. Ann Plast Surg 1997;38:553-62. doi: 10.1097/00000637- 199706000-00001.

15) Yu AW, Rippel RA, Smock E, Jarral OA. In patients with post-sternotomy mediastinitis is vacuum-assisted closure superior to conventional therapy? Interact Cardiovasc Thorac Surg 2013;17:861-5. doi: 10.1093/icvts/ivt326.

16) Lee AB Jr, Schimert G, Shaktin S, Seigel JH. Total excision of the sternum and thoracic pedicle transposition of the greater omentum; useful strategems in managing severe mediastinal infection following open heart surgery. Surgery 1976;80:433-6.

17) Jurkiewicz MJ, Bostwick J 3rd, Hester TR, Bishop JB, Craver J. Infected median sternotomy wound. Successful treatment by muscle flaps. Ann Surg 1980;191:738-44. doi:10.1097/00000658-198006000-00012.

18) Akbayrak H, Tekumit H. Comparison between vacuumassisted closure technique and conventional approach in patients with mediastinitis after isolated coronary artery bypass graft surgery. Braz J Cardiovasc Surg 2023;38:353-9. doi: 10.21470/1678-9741-2022-0317.

19) Akyıldız Ö, Ulular Ö. Evaluation of post-operative development of mediastinitis in patients undergoing isolated coronary artery bypass grafting surgery: A single-center experience. Ulus Travma Acil Cerrahi Derg 2022;28:180-6. doi: 10.14744/tjtes.2020.13546.

20) Lee AJ, Sheppard CE, Kent WD, Mewhort H, Sikdar KC, Fedak PW. Safety and efficacy of prophylactic negative pressure wound therapy following open saphenous vein harvest in cardiac surgery: A feasibility study. Interact Cardiovasc Thorac Surg 2017;24:324-8. doi: 10.1093/icvts/ ivw400.

21) Şahin MF, Yazıcıoğlu A, Beyoğlu MA, Yekeler E. Successful method in the treatment of complicated sternal dehiscence and mediastinitis: Sternal reconstruction with osteosynthesis system supported by vacuum-assisted closure. Turk Gogus Kalp Damar Cerrahisi Derg 2022;30:57-65. doi: 10.5606/ tgkdc.dergisi.2022.20958.

22) Gårdlund B, Bitkover CY, Vaage J. Postoperative mediastinitis in cardiac surgery - microbiology and pathogenesis. Eur J Cardiothorac Surg 2002;21:825-30. doi: 10.1016/s1010- 7940(02)00084-2.

23) Trouillet JL, Vuagnat A, Combes A, Bors V, Chastre J, Gandjbakhch I, et al. Acute poststernotomy mediastinitis managed with debridement and closed-drainage aspiration: Factors associated with death in the intensive care unit. J Thorac Cardiovasc Surg 2005;129:518-24. doi: 10.1016/j. jtcvs.2004.07.027.

24) Rashed A, Frenyo M, Gombocz K, Szabados S, Alotti N. Incisional negative pressure wound therapy in reconstructive surgery of poststernotomy mediastinitis. Int Wound J 2017;14:180-3. doi: 10.1111/iwj.12579.

25) Liu YT, Lin SH, Peng C, Huang RW, Lin CH, Hsu CC, et al. Effectiveness and safety of negative pressure wound therapy in patients with deep sternal wound infection: A systematic review and meta-analysis. Int J Surg 2024;110:8107-25. doi:10.1097/JS9.0000000000002138.

26) Othman D. Negative pressure wound therapy literature review of efficacy, cost effectiveness, and impact on patients' quality of life in chronic wound management and its implementation in the United kingdom. Plast Surg Int 2012;2012:374398. doi:10.1155/2012/374398.

27) Saramago P, Gkekas A, Arundel CE, Chetter IC; SWHSI- 2 Trial Investigators. Negative pressure wound therapy for surgical wounds healing by secondary intention is not cost-effective. Br J Surg 2025;112:znaf077. doi: 10.1093/bjs/ znaf077.

28) Älgå A, Löfgren J, Haweizy R, Bashaireh K, Wong S, Forsberg BC, et al. Cost analysis of negative-pressure wound therapy versus standard treatment of acute conflict-related extremity wounds within a randomized controlled trial. World J Emerg Surg 2022;17:9. doi: 10.1186/s13017-022- 00415-1.