Surgical Site Infections in Cardiac Surgery

Mortality Associated with Surgical Site Infections Following Cardiac Surgery: Insights from the International ID-IRI Study

Objectives

Surgical site infections (SSIs) after cardiac surgery increase morbidity and mortality rates. This multicenter study aimed to identify mortality risk factors associated with SSIs after heart surgery.

Methods

Conducted from January to March 2023, this prospective study included 167 patients aged >16 years with post-heart surgery SSIs. The primary focus was the 30-day mortality. Univariate analysis and multivariate logistic regression utilizing the backward elimination method were used to establish the final model.

Results

Several factors significantly correlated with mortality. These included urinary catheterization (odds ratio [OR] 14.197; 90% confidence interval [CI] 12.198-91.721]), emergent surgery (OR 8.470 [90% CI 2.028-35.379]), valvular replacement (OR 4.487 [90% CI 1.001-20.627]), higher quick Sequential Organ Failure Assessment scores (OR 3.147 [90% CI 1.450-6.827]), advanced age (OR 1.075 [90% CI 1.020-1.132]), and postoperative re-interventions within 30 days after SSI (OR 14.832 [90% CI 2.684-81.972]). No pathogens were isolated from the wound cultures of 53 (31.7%) patients. A total of 43.1% of SSIs (n = 72) were due to gram-positive microorganisms, whereas 27.5% of cases (n = 46) involved gram-negatives. Among the gram-positive bacteria, Staphylococci (n = 30, 17.9%) were the predominant microorganisms, whereas Klebsiella (n = 16, 9.6%), Escherichia coli (n = 9, 5.4%), and Pseudomonas aeruginosa (n = 7, 4.2%) were the most prevalent.

Conclusions

To mitigate mortality after heart surgery, stringent infection control measures and effective surgical antisepsis are crucial, particularly, in the elderly. The clinical progression of the disease is reflected by the quick Sequential Organ Failure Assessment score and patient re-intervention, and effective treatment is another essential component of SSI management.

Enhanced Recovery After Surgery Cardiac Society turnkey order set for surgical-site infection prevention: Proceedings from the American Association for Thoracic Surgery ERAS Conclave 2023

OBJECTIVES

Surgical-site infections (SSIs) after cardiac surgery increase morbidity and mortality, consume health care resources, impair recovery, and diminish patients' quality of life. Numerous guidelines and expert consensus documents have been published to address the prevention and management of SSIs. Our objective is to integrate these documents into an order set that will facilitate the adoption and implementation of evidence-based best practices for preventing and managing SSIs after cardiac surgery.

METHODS

Subject matter experts were consulted to translate existing guidelines and literature into a sample turnkey order set for SSI reduction. Orders derived from consistent class I, IIA, or equivalent recommendations across referenced guidelines and consensus manuscripts appear in the turnkey order set in bold type. Selected orders that were inconsistent class I or IIA, class IIB or otherwise supported by published evidence, were also included in italicized type.

RESULTS

Preventative care begins with the preoperative identification of both modifiable and nonmodifiable SSI risks by health care providers. Assessment tools can be used to assist in identifying patients at a high risk of SSI. Preoperative recommendations include screening for and treating Staphylococcus aureus nasal carriage. Intraoperatively, tailored prophylactic intravenous antibiotics and maintaining blood glucose levels below 180 mg/dL are essential elements. Postoperative care includes maintaining normothermia, glucose control and patient engagement.

CONCLUSIONS

Despite the well-documented advantages of a multidisciplinary care pathway for SSI in cardiac surgery, there are inconsistencies in its adoption and implementation. This article provides an order set that incorporates recommendations from existing guidelines to prevent SSI in the cardiac surgical population.

Bioengineering Approaches and Novel Biomaterials to Enhance Sternal Wound Healing after Cardiac Surgery: A Crosstalk between Innovation and Surgical Practice

Median sternotomy and steel wires for sternal closure are the standard approach for cardiac surgery. An incomplete repair associated with chest wall motion, especially in the presence of predisposing factors, can lead to life-threatening deep sternal wound infection, also known as mediastinitis, in 2-5% of cases. Despite current antibiotic and surgical treatments, mediastinitis is associated with a 10-40% mortality rate and a significant increase in morbidity and hospital stay. High mortality and difficult treatment appear to be due to bacterial biofilm, a self-produced extracellular polymeric product that incorporates host tissue and is responsible for the failure of immune defenses and standard antimicrobial therapies. Nanostructures are an effective strategy to enhance the healing process, as they establish a favorable environment for the neosynthesis of the extracellular matrix, supporting tissue development. Synthetic polymers have been proven to exhibit suitable biodegradable and mechanical properties, and their biofunctionalization to enhance cell attachment and interaction with the extracellular matrix is being widely investigated. The use of antibiotic treatments suspended in poly-D,L-lactide and polyethylene oxide and electrospun into nanofibers, or in sponges, has been shown to inhibit bacterial biofilm production. Additionally, growth factors can be incorporated into 3D bioresorbable scaffolds with the aim of constituting a structural and biological framework to organize and expedite the healing process. Therefore, these combined approaches may change the treatment of mediastinitis in the near future.

The prophylactic use of negative-pressure wound therapy after cardiac surgery: a meta-analysis

Surgical site infections (SSIs) pose a frequent complication in cardiac surgery patients and lead to increased patient discomfort and extended hospitalization. This meta-analysis aimed to evaluate the protective role of single-use negative-pressure wound therapy (sNPWT) devices on closed surgical wounds after cardiac surgery, and explored their potential preventive application across all cardiac surgery patients. A comprehensive literature search was conducted on ScienceDirect, focusing on studies related to "negative pressure wound therapy" or "PICO negative pressure wound therapy" combined with "cardiac surgery" or "sternotomy," published between 2000 and 2022. Inclusion criteria encompassed case-control studies comparing sNPWT with traditional dressings on closed cardiac surgical incisions in adult patients undergoing median sternotomy without immediate postoperative infective complications, with available details on SSIs. A retrospective analysis of cases treated with sNPWT in our centre was also performed. The meta-analysis revealed a protective role of sNPWT, indicating a 44% risk reduction in overall SSIs (odds ratio 0.56) and a 40% risk reduction in deep wound infections (odds ratio 0.60). Superficial wound infections, however, showed non-significant protective effects. A single-centre study aligned with the meta-analysis findings, confirming the efficacy of sNPWT and was included in the meta-analysis. In conclusion, the meta-analysis and the single-centre study collectively support the protective role of negative pressure wound therapy against overall and deep SSIs, suggesting its potential prophylactic use on all cardiac surgery populations.

Risk factors associated with surgical site infections in patients undergoing cardiothoracic surgery: A systematic review and meta-analysis

Surgical site infections (SSIs) following cardiothoracic surgery can pose significant challenges to patient recovery and outcome. This systematic review and meta-analysis aim to identify and quantify the risk factors associated with SSIs in patients undergoing cardiothoracic surgery. A comprehensive literature search adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and based on the PICO paradigm was conducted across four databases: PubMed, Embase, Web of Science and the Cochrane Library, without any temporal restrictions. The meta-analysis incorporated studies detailing the risk factors for post-operative sternal infections, especially those reporting odds ratios (OR) or relative risks with 95% confidence intervals (CI). Quality assessment of the studies was done using the Newcastle-Ottawa Scale. Statistical analysis was executed using the chi-square tests for inter-study heterogeneity, with further analyses depending on I2 values. Sensitivity analyses were performed, and potential publication bias was also assessed. An initial dataset of 2442 articles was refined to 21 articles after thorough evaluations based on inclusion and exclusion criteria. Patients with diabetes mellitus have an OR of 1.80 (95% CI: 1.40-2.20) for the incidence of SSIs, while obese patients demonstrate an OR of 1.63 (95% CI: 1.40-1.87). Individuals who undergo intraoperative blood transfusion present an OR of 1.13 (95% CI: 1.07-1.18), and smokers manifest an OR of 1.32 (95% CI: 1.03-1.60). These findings unequivocally indicate a pronounced association between these factors and an elevated risk of SSIs post-operatively. This meta-analysis confirms that diabetes, obesity, intraoperative transfusion and smoking heighten the risk of SSIs post-cardiac surgery. Clinicians should be alert to these factors to optimise patient outcomes.

Enhanced recovery after cardiac surgery: A literature review

Enhanced recovery after cardiac surgery (ERACS) represents a constellation of evidence-based peri-operative methods aimed to reduce the physiological and psychological stress patients experience after cardiac surgery, with the primary objective of providing an expedited recovery to pre-operative functional status. The method involves pre-operative, intra-operative, and post-operative interventions as well as direct patient engagement to be successful. Numerous publications in regard to the benefits of enhanced recovery have been presented, including decreased post-operative complications, shortened length of stay, decreased overall healthcare costs, and higher patient satisfaction. Implementing an ERACS program undeniably requires a culture change, a methodical shift in the approach of these patients that ultimately allows the team to achieve the aforementioned goals; therefore, team-building, planning, and anticipation of obstacles should be expected.

Perioperative Care in Cardiac Surgery: A Joint Consensus Statement by the Enhanced Recovery After Surgery (ERAS) Cardiac Society, ERAS International Society, and The Society of Thoracic Surgeons (STS)

Enhanced Recovery After Surgery (ERAS) programs have been shown to lessen surgical insult, promote recovery, and improve postoperative clinical outcomes across a number of specialty operations. A core tenet of ERAS involves the provision of protocolized evidence-based perioperative interventions. Given both the growing enthusiasm for applying ERAS principles to cardiac surgery and the broad scope of relevant interventions, an international, multidisciplinary expert panel was assembled to derive a list of potential program elements, review the literature, and provide a statement regarding clinical practice for each topic area. This article summarizes those consensus statements and their accompanying evidence. These results provide the foundation for best practice for the management of the adult patient undergoing cardiac surgery.

Infectious complications following major heart surgery from the day of the surgery to hospital discharge

BACKGROUND

At some point in their lives, many people will require major heart surgery (MHS). Patients are generally older adults with various risk factors for infection. However, the incidence of infection after MHS is poorly known, as reported infection data are frequently biased due to different factors like the surgical procedure, postoperative timing, and infectious syndromes or etiologic agents, among others. In addition, most patient data are retrospectively obtained.

PURPOSE AND METHODS

Data were prospectively collected regarding the incidence of all nosocomial infections produced from the time of surgery to hospital discharge in a cohort of 800 adults consecutively undergoing a MHS procedure.

RESULTS

During postoperative hospitalization, 124 of the 800 participants developed one or more infections (15.5%): during their ICU stay in 68 patients (54.8%), during their stay on the general ward post ICU in 50 (40.3%), and during their stay in both wards in 6 (4.8%). The most common infections were pneumonia (related or not to mechanical ventilation), surgical site and bloodstream. As etiological agents, 193 pathogens were isolated: mostly Gram-negative bacilli (54.4%), followed by Gram-positive bacteria (30%), viruses (4.6%) and fungi (1.5%). In our cohort, all-cause mortality was recorded in 33 participants (4.1%) and 9 infection-related deaths (1.1%) were produced. Among subjects who developed infections, overall mortality was 13.7% and in those who did not, this was only 2.3%.

CONCLUSION

Infection following MHS remains frequent and severe. Our data suggest that hospital-acquired infection studies should consider episodes of infection in all populations during their entire hospital stay and not only those related to specific clinical syndromes or acquired while the patient is in intensive care.

Surgical site infection outcomes of two different closed incision negative pressure therapy systems in cardiac surgery: Systematic review and meta-analysis

Closed incision negative pressure therapy (ciNPT) system use compared with standard of care dressings (SOC) on surgical site infection (SSI) in cardiac surgery was assessed. A systematic literature review was conducted. Risk ratios (RR) and random effects models were used to assess ciNPT with foam dressing (ciNPT-F) or multilayer absorbent dressing (ciNPT-MLA) versus SOC. Health economic models were developed to assess potential per patient cost savings. Eight studies were included in the ciNPT-F analysis and four studies were included in the ciNPT-MLA analysis. For ciNPT-F, a significant reduction in SSI incidence was observed (RR: 0.507, 95% confidence interval [CI]: 0.362, 0.709; p < 0.001). High-risk study analysis reported significant SSI reduction with ciNPT-F use (RR: 0.390, 95% CI: 0.205, 0.741; p = 0.004). For ciNPT-MLA, no significant difference in SSI rates were reported (RR: 0.672, 95% CI: 0.276, 1.635; p = 0.381). Health economic modelling estimated a per patient cost savings of $554 for all patients and $3242 for the high-risk population with ciNPT-F use. Health economic modelling suggests ciNPT-F may provide a cost-effective solution for sternotomy incision management. However, limited high-quality literature exists. More high-quality evidence is needed to fully assess the impact of ciNPT use following cardiac surgery.

Surgical Strategy for Sternal Closure in Patients with Surgical Myocardial Revascularization Using Mammary Arteries

BACKGROUND

Coronary artery bypass grafting has evolved from all venous grafts to bilateral mammary artery (BIMA) grafting. This was possible due to the long-term patency of the left and right internal mammary demonstrated in angiography studies compared to venous grafts. However, despite higher survival rates when using bilateral mammary arteries, multiple studies report a higher rate of surgical site infections, most notably deep sternal wound infections, a so-called "never event".

METHODS

We designed a prospective study between 1 January 2022 and 31 December 2022 and included all patients proposed for total arterial myocardial revascularization in order to investigate the rate of surgical site infections (SSI). Chest closure in all patients was performed using a three-step protocol. The first step refers to sternal closure. If the patient's BMI is below 35 kg/m2, sternal closure is achieved using the "butterfly" technique with standard steel wires. If the patient's BMI exceeds 35 kg/m2, we use nitinol clips or hybrid wire cable ties according to the surgeon's preference for sternal closure. The main advantages of these systems are a larger implant-to-bone contact with a reduced risk of bone fracture. The second step refers to presternal fat closure with two resorbable monofilament sutures in a way that the edges of the skin perfectly align at the end. The third step is skin closure combined with negative pressure wound therapy.

RESULTS

This system was applied to 217 patients. A total of 197 patients had bilateral mammary artery grafts. We report only 13 (5.9%) superficial SSI and only one (0.46%) deep SSI. The preoperative risk of major wound infection was 3.9 +/- 2.7. Bilateral mammary artery grafting was not associated with surgical site infection in a univariate analysis.

CONCLUSIONS

We believe this strategy of sternal wound closure can reduce the incidence of deep surgical site infection when two mammary arteries are used in coronary artery bypass surgery.

The impact of COVID-19 prevention measures on surgical wound infection rates post-cardiac surgery

The COVID-19 pandemic had a huge impact on medical services. Several measures have been implemented to reduce the risk of viral transmission. In this paper, we assessed the impact of these measures on surgical wound infection rates in post-cardiac surgery patients. Hypothesis testing was used to compare post-cardiac operation infection rates between the year prior to the COVID-19 pandemic being declared and the first 13 months of the pandemic. The infection rates in 969 patients with operations between 01/03/2019 and 29/02/2020 were compared to those of 925 patients with cardiac surgery between 01/03/2020 and 31/03/2021. Infection rates for various operative urgencies and infection types were analyzed. To compare infection rates, a two-tailed pooled z-test using the difference in infection proportions was performed. A 5% significance level was used, and only categories with at least 10 patients in both the pre-COVID and COVID populations were tested. For leg infections, only operations involving coronary artery bypass grafting were included. To ensure that any differences in outcomes were not due to differences in patient demographics resulting in unequal operative risks, Euroscore II values, a measure of cardiac operative risk, were compared between the pre-COVID and post-COVID cohorts. The Mann-Whitney U-test was used to determine whether the distributions of Euroscore II values were likely to be drawn from the same population. A significance level of 5% was used. A total of 1901 patients (932 during the COVID-19 pandemic) were included in this study. There was a significant reduction in post-operative infections for all patients undergoing cardiac surgery, from 4.3% of patients before COVID-19 to 1.5% during the pandemic. During the pandemic, fewer elective and more urgent operations were performed. This study suggests a significant role for iatrogenic causes in wound infections before the pandemic. The implementation of COVID-19 prevention measures by healthcare providers can reduce surgical infection rates. As COVID-19-related restrictions have been eased, we suggest maintaining them for healthcare providers to reduce the incidence of surgical wound infections.

Influence and risk factors of postoperative infection after surgery for ischemic cardiomyopathy

Background

Studies on postoperative infection (POI) after surgery for ischemic cardiomyopathy are still lacking. This study aimed to investigate the risk factors of POI and its influence on clinical outcomes in patients undergoing ischemic cardiomyopathy surgery.

Methods

The Surgical Treatment for Ischemic Heart Failure (STICH) trial randomized patients with ischemic cardiomyopathy [coronary artery disease (CAD) with left ventricular ejection fraction ≤35%] to surgical and medical therapy. In this study, a post hoc analysis of the STICH trial was performed to assess the risk factors and clinical outcomes of POI in those undergoing coronary artery bypass graft (CABG). Patients were divided according to whether POI developed during hospitalization or within 30 days from operation.

Results

Of the 2,136 patients randomized, 1,460 patients undergoing CABG per-protocol was included, with a POI rate of 10.2% (149/1,460). By multivariable analysis, POI was significantly related to patients' age, body mass index, depression, chronic renal insufficiency, Duke CAD Index, and mitral valve procedure. Compared to patients without POI, patients with POI had significantly longer durations of intubation, CCU/ICU and hospital stay, and higher rates of re-operation, in-hospital death and failed discharge within 30 days postoperatively. In addition, these patients had significantly higher risks of all-cause death, cardiovascular death, heart failure death, and all-cause hospitalization during long-term follow-up. However, the influence of POI on all-cause death was mainly found during the first year after operation, and the influence was not significant for patients surviving for more than 1 year.

Conclusions

POI was prevalent after surgery for ischemic cardiomyopathy and was closely related to short-term and long-term clinical outcomes, and the effect of POI mainly occurred within the first postoperative year. This study first reported and clarified the relationship between POI and long-term prognosis and the predictors for POI after surgery for ischemic cardiomyopathy worldwide, which may have certain guiding significance for clinical practice.

Clinical Trial Registration

https://www.clinicaltrials.gov, identifier (NCT00023595).

Intranasal Mupirocin to Reduce Surgical Site Infection Post Cardiac Surgery: A Review of the Literature

Sternal wound infections after cardiac surgery are associated with high rates of morbidity and mortality. One of the known risk factors of sternal wound infection is Staphylococcus aureus colonisation. Intranasal mupirocin decolonisation therapy implemented pre-operatively appears to be an effective preventative measure in reducing sternal wound infections post-cardiac surgery. Therefore, the main aim of this review is to evaluate the current literature regarding the use of intranasal mupirocin before cardiac surgery and its impact on sternal wound infection rates.