Metagenomic Next-Generation Sequencing in the Diagnosis of Deep Sternal Wound Infection After Cardiac Transplantation: A Case Report and Literature Review

Purpose: To explore the value of metagenomics next-generation sequencing (mNGS) for deep sternal wound infection (DSWI) diagnosis. Methods: mNGS was used to diagnose DSWI after cardiac transplantation; DSWI was treated with surgical debridement, wound care, and antibiotic therapy guided by mNGS. Results: Coinfection of methicillin-resistant Staphylococcus aureus (MRSA) and cytomegalovirus (CMV) was detected in this patient. The infection was controlled and the wound healed successfully with the specific medicine based on mNGS results for 3 weeks. Conclusion: mNGS is effective to achieve precise, individualized, and rapid treatment for wound infection.

Supplementing Existing Societal Risk Models for Surgical Aortic Valve Replacement With Machine Learning for Improved Prediction

Background This study evaluated the role of supplementing Society of Thoracic Surgeons (STS) risk models for surgical aortic valve replacement with machine learning (ML). Methods and Results Adults undergoing isolated surgical aortic valve replacement in the STS National Database between 2007 and 2017 were included. ML models for operative mortality and major morbidity were previously developed using extreme gradient boosting. Concordance and discordance in predicted risk between ML and STS models were defined using equal‐size tertile‐based thresholds of risk. Calibration metrics and discriminatory capability were compared between concordant and discordant patients. A total of 243 142 patients were included. Nearly all calibration metrics were improved in cases of concordance. Similarly, concordance indices improved substantially in cases of concordance for all models with the exception of deep sternal wound infection. The greatest improvements in concordant versus discordant cases were in renal failure: ML model (concordance index, 0.660 [95% CI, 0.632–0.687] discordant versus 0.808 [95% CI, 0.794–0.822] concordant) and STS model (concordance index, 0.573 [95% CI, 0.549–0.576] discordant versus 0.797 [95% CI, 0.782–0.811] concordant) (each P <0.001). Excluding deep sternal wound infection, the concordance indices ranged from 0.549 to 0.660 for discordant cases and 0.674 to 0.808 for concordant cases. Conclusions Supplementing ML models with existing STS models for surgical aortic valve replacement may have an important role in risk prediction and should be explored further. In particular, for the roughly 25% to 50% of patients demonstrating discordance in estimated risk between ML and STS, there appears to be a substantial decline in predictive performance suggesting vulnerability of the existing models in these patient subsets.

Retrospective Analysis of Flap Based Management in Deep Sternal Wound Infection in a Tertiary Care Centre –A Single Centre Study

Aims: In this retrospective study we analyzed the outcomes of flap based management in deep sternal wound infection (DSWI). Materials & Methods: Patients, who had undergone open heart surgery through median sternotomy between September 2017 and March 2020 and had developed deep sternal infections, were retrospectively analyzed in this study. Few patients found to have DSWI were managed only by Negative Pressure Wound Therapy (NPWT) and few were managed by NPWT and Bipectoral musculo fascial flap cover. The outcomes in terms of mortality and readmission in the postoperative course were obtained from the records during subsequent follow ups in OPD for six months. Results: Out of 925 patients 11 patients (1.2%) had deep sternal wound infection There were six patients (n=6, 54.55%) who received NPWT where as five patients (n=5, 45.45 %) received flap surgery following NPWT. The patient who underwent Flap surgery had a longer postoperative stay than NPWT group (46.2+/- 22.21, C.I 95%) days Vs (25.5+/- 14.41, C.I 95%) days. However, the readmission due to recurrence of infection was seen only in NPWT group (n=3, 50%) with in the period of six months following discharge. One patient out of the three readmitted patients expired due to sepsis. Conclusion: NPWT followed by bipectoral muscle flap closure has a better surgical outcome than NPW alone in deep sternal wound infection in early postoperative period

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

Background Deep sternal wound infection (DSWI) is a rare but serious complication after median sternotomy, and treatment success depends mainly on surgical experience. Here we first present a case of a patient successfully treated for antibiotic-loaded bone cement (ALBC) combined with vacuum sealing drainage (VSD) of DSWI. Case presentation This case report presented a patient who underwent open heart surgery, and suffered postoperatively from a DSWI associated with enterococcus cloacae. Focus debridement combined with ALBC filling and VSD was conducted in stage I. Appropriate antibiotics were started according to sensitivity to be continued for 2 weeks until the inflammatory markers decreased to normal. One month after the surgery, patient’s wound was almost healed and was discharged from hospital with a drainage tube. Two months after the stage I surgery procedure, the major step was removing the previous ALBC, and extensive debridement in stage II. The patient fully recovered without further surgical treatment. Conclusions The results of this case suggest that ALBC combined with VSD may be a viable and safe option for deep sternal wound reconstruction.

Decreasing complications of pectoralis major muscle flap reconstruction with two modalities of negative pressure wound therapy

Background and objective: Deep sternal wound infection is a feared complication of open-heart surgery. Negative pressure wound therapy has gained an important role in the treatment of deep sternal wound infection. Incisional negative pressure wound therapy has been introduced as a method to prevent wound complications after sternotomy, and lately, after flap reconstructions in the treatment of deep sternal wound infection. We aimed to study if incisional negative pressure wound therapy with PICO™ had similar beneficial effect described earlier with competing commercial devices. Methods: This study included 82 patients treated with pectoralis major muscle flap for deep sternal wound infection during the years 2006–2020. PICO group consisted of 24 patients treated with preoperative negative pressure wound therapy and postoperative incisional negative pressure wound therapy (PICO™). Two control groups included 48 patients with conventional treatment and 10 patients with preoperative negative pressure wound therapy only. Results: In the PICO group, the complication rate declined from 50.0% to 33.30%, major complication rate from 29.2% to 12.5%, and need for an additional flap from 14.6.% to 4.2% when compared to conventional treatment. The length of hospital stay decreased as well. Preoperative negative pressure wound therapy alone was associated with moderate decline in the complication rates. In addition, we described the use of split pectoralis major muscle flap reconstruction in 57 patients. To our knowledge, this is the largest published patient series describing this method in the treatment of deep sternal wound infection. Conclusions: Incisional negative pressure wound therapy with PICO™ seems beneficial after flap reconstruction. Split pectoralis major muscle flap is a versatile reconstruction option suitable to be used as a workhorse in the treatment of deep sternal wound infection.

Risk Factors Associated with an Increased Risk of Deep Sternal Wound Infections in Patients After Coronary Artery Bypass Grafting and Heart Defect Surgery

Background: Despite improvements over time with regard to morbidity, mortality, and long-term survival, deep sternal wound infection (DSWI) continues to be a major complication after open-heart surgery. This is why it is important to identify possible risk factors for postoperative development of DSWI in patients undergoing coronary artery bypass grafting and valve replacement. The aim of this study was to identify the risk factors for postoperative development of deep sternal wound infection in patients after coronary artery bypass grafting and heart defect surgery at the Department of Thoracic, Cardiac, and Vascular Surgery of the Hospital of Lithuanian University of Health Sciences. Methods: This retrospective study analyzed 201 patients, who underwent coronary artery bypass grafting and heart defect surgery between January 2017 and December 2018. The case group contained 45 patients, who had to be reoperated because of deep sternal wound infection, and the control group consisted of 156 randomly selected patients. For descriptive statistics, we used means, median values, ranges, standard deviations, and 95% confidence intervals, where appropriate. Categorical data were analyzed using the chi-square or Fisher’s exact test. Student T-test and Mann-Whitney used to compare numerical variables. Logistic regression model adjusting for age and gender was used to compare the risk of infection. A P-value of < 0.05 was considered to be statistically significant. SPSS 26.0 was used for calculations. Results: Logistic regression analysis revealed that independent risk factors for sternal wound infection were high BMI (odds ratio [OR] 1.15, CI 1.06-1.24), preoperative CRP (OR 1.08, CI 1.01-1.16), long duration of cardiopulmonary bypass (OR 1.02, CI 1.01-1.03), intraoperative anemia (OR 0.97, CI 0.95-0.99), and postoperative CRP concentration (OR 1.10; CI 1.05-1.16). Conclusions: Preoperative assessment to identify obese individuals as being at risk and techniques to minimize the duration of surgery and intraoperative blood loss may help reduce postoperative deep sternal wound infections.

Dual Topical Antibiotic Application Prior to Sternotomy Closure Reduces Sternal Wound Infection Rates: A Simple Solution to a Grave Morbidity

Background: A significant cohort of patients who undergo cardiac surgery suffer from diabetes and atherosclerosis. These patients have impaired tissue perfusion, hence a reduction in antibiotic concentration in the subcutaneous tissues at the side of the mammary artery harvesting. Topical application of gentamicin and vancomycin before wound closure broadens the antibiotic spectrum and reduces the incidence of deep sternal wound infection. In this article, we compare the use of single versus dual application of vancomycin and/or gentamicin in sternotomy wounds in a single tertiary center. Methods: An observational cohort analysis with three sequential patient groups (N = 2550) was performed at Ain Shams University Hospital in Cairo. A control group (N = 850), vancomycin only group (N = 850), and vancomycin plus gentamicin group (N = 850) were included in the study, during the three-year period from January 2017 to December 2019. Patients who had minimal access surgery were excluded from this study. The presence of an infected postoperative sternotomy wound was assessed in all patients. Results: The presence of an infected sternotomy wound (El Oakley class 2B) was present in 38 patients (4.5%) in the control group, in 19 patients (2.2%) in the vancomycin group, and in nine patients (1.1%) in the dual antibiotic group, respectively (P < .001). In contrast to the usual, we had a proliferous growth of gram-negative organisms 29 (3.4%) in the control group, 10 (1.2%) in the vancomycin group, and five (0.6%) in the dual antibiotic group, respectively (P < .001). Conclusion: Deep sternal wound infection is a major cause of post-cardiac surgery morbidity and prolonged hospital stay. Adding the simple step of topical application of vancomycin and gentamicin to the sternotomy wound at the end of the procedure appeared to significantly reduce deep wound infection rates.