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.

Performance of a Novel Risk Model for Deep Sternal Wound Infection after Coronary Artery Bypass Grafting

Clinical prediction models for deep sternal wound infections (DSWI) after coronary artery bypass graft (CABG) surgery exist, although they have a poor impact in external validation studies. We developed and validated a new predictive model for 30-day DSWI after CABG (REPINF) and compared it with the Society of Thoracic Surgeons model (STS). The REPINF model was created through a multicenter cohort of adults undergoing CABG surgery (REPLICCAR II Study) database, using least absolute shrinkage and selection operator (LASSO) logistic regression, internally and externally validated comparing discrimination, calibration in-the-large (CL), net reclassification improvement (NRI) and integrated discrimination improvement (IDI), trained between the new model and the STS PredDeep, a validated model for DSWI after cardiac surgery. In the validation data, c-index = 0.83 (95% CI 0.72–0.95). Compared to the STS PredDeep, predictions improved by 6.5% (IDI). However, both STS and REPINF had limited calibration. Different populations require independent scoring systems to achieve the best predictive effect. As the STS, the REPINF external validation across multiple centers it’s important to guide healthcare professionals as a quality improvement tool in the prevention of DSWI after CABG surgery.

Risk factors for 30-day mortality in patients who received DeBakey type I aortic dissection repair surgery

Objective This study aimed to identify risk factors for 30-day mortality in patients who received DeBakey type I aortic dissection (AD) repair surgery. Methods A total of 830 consecutive patients who received acute DeBakey type I AD surgery between 2014 and 2019 were included in the study. The associations between 30-day mortality and perioperative parameters were examined in order to identify risk factors. Results Our data suggested that the overall 30-day mortality rate of all enrolled patients was 11.7%. Unsurprisingly, non-survivors were older and more frequently accompanied with histories of cardiovascular diseases. For intraoperative parameters, the prevalence of coronary artery bypass grafting and cardiopulmonary bypass times were increased in non-survivors. In addition, acute kidney injury (AKI), dialysis, stroke, and deep sternal wound infection were more commonly seen among non-survivors. The multivariate logistic regression analysis suggested that cardiovascular disease history, preoperative D-dimer level, drainage volume 24 h after surgery, and postoperative AKI were independent risk factors for 30-day mortality after DeBakey type I aortic dissection repair surgery. Conclusions Our study demonstrated that cardiovascular disease history, preoperative D-dimer level, drainage volume 24 h after surgery as well as postoperative AKI were risk factors for 30-day mortality after DeBakey type I aortic dissection repair surgery.

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.

Impact of Bedside Re-Explorations in a Cardiovascular Surgery Intensive Care Unit Led by Surgeons

Surgical re-explorations represent 3–5% of all cardiac surgery. Concerns regarding mortality and major morbidity of re-explorations in the intensive care unit (ICU) setting exist. We sought to investigate whether they may have different outcomes compared with those performed in the operating room (OR). Single center retrospective review of patients who underwent mediastinal re-exploration in the ICU or in the OR after cardiac surgery. Mediastinal re-explorations were also classified as: “planned” and “unplanned”. Primary outcome was 30-day mortality, secondary outcomes include deep sternal wound infection (DSWI), sepsis, ICU and hospital length of stay, prolonged intubation (>72 h), tracheostomy, pneumonia, acute kidney injury requiring dialysis and stroke. Between 2010 and 2019, 195 of 7263 patients (2.7%) underwent mediastinal re-exploration after cardiac surgery. More patients in the ICU group experienced two or more re-explorations (30.3% vs 2.3%, p < 0.001), a higher incidence of postoperative pneumonia (22% vs 7%, p = 0.004), prolonged intubation (46.8% vs 19.8%, p < 0.001) and longer hospital stay (30.3 ± 34.2 vs. 20.8 ± 18.3 days, p = 0.014). There were no differences in mortality between ICU and OR (16.5% vs. 13.9%, p = 0.24) nor in sepsis (14.7% vs 7%, p = 0.91) and DSWI rates (1.8% vs 1.2%, p = 0.14). Re-explorations in the ICU were not associated with increased mortality, sepsis and mediastinitis rate.

Multiple Grafting with Single Left Internal Mammary Artery as T-Graft with Itself

Background Revascularization strategies might be limited in patients with lack of sufficient bypass graft material and increased risk of wound healing disturbances. In this regard, we present first results of patients treated with left internal mammary artery (LIMA) as T-graft with itself due to left-sided double-vessel disease, elevated risk of wound healing infection, and lack of graft material. Methods Eighteen patients were retrospectively analyzed in this study. All patients received LIMA grafting, and additional T-graft with itself during off-pump coronary artery bypass surgery. The investigation was focused on intraoperative and postoperative outcomes. Results LIMA-LIMA T-graft was performed in a total of 18 patients. Mean Fowler score accounted for 18.2 ± 2.9. Severe vein varicosis was present in 9 patients, and 38.9% of patients had lacking venous graft material due to prior vein stripping. A total of 2.5 ± 0.5 distal anastomoses were performed. Mean flow of LIMA—left anterior descending anastomosis was 41.72 ± 12.11 mL/min with a mean pulsatility index (PI) of 1.01 ± 0.21. Mean flow of subsequent T-graft accounted for 26.31 ± 4.22 mL/min with a mean PI of 1.59 ± 0.47. Median hospital stay was 7(6.75;8) days. No incidence of postoperative wound healing disorders was observed and all patients were discharged off hospital. Conclusions LIMA as T-graft with itself to treat left-sided double-vessel disease is feasible and safe in patients with missing bypass graft material and increased risk of deep sternal wound infection. Further prospective studies are necessary to confirm our results.