Deep sternal wound infection after coronary artery bypass surgery: management and risk factor analysis for mortality

Effectiveness and safety of negative pressure wound therapy in patients with deep sternal wound infection: a systematic review and meta-analysis

BACKGROUND

Deep sternal wound infection (DSWI) is a severe and life-threatening complication following cardiovascular surgery. Negative pressure wound therapy (NPWT) has emerged as a promising therapeutic bridging option for DSWI. In this systematic review and meta-analysis, the authors aimed to evaluate the impact of NPWT on clinical outcomes in patients with DSWI.

MATERIAL AND METHODS

A comprehensive literature search was conducted according to the PRISMA guideline in electronic databases, including PubMed, Embase, and Cochrane Library. Data extraction was performed independently by two reviewers, and risk of bias was assessed by ROBINS-I tool. The primary outcomes assessed were mortality rate and reinfection rate. The secondary outcomes assessed were length of hospital stay and ICU stay.

RESULTS

In this systematic review identified a total of 36 studies, comprising 3681 patients with DSWI who received treatment. The meta-analysis revealed that NPWT was associated with a significant reduction in mortality rate (RR 0.46, 95% CI: 0.35-0.61, P<0.000001) and reinfection rate (RR 0.43, 95% CI: 0.25-0.74, P=0.002) compared to conventional wound management. Furthermore, pooling of these studies showed significant difference between the NPWT and conventional treatment groups in length of hospital stay (mean difference: -4.49, 95% CI: -8.14 to -0.83; P=0.02) and length of ICU stay (mean difference: -1.11, 95% CI: -2.18 to -0.04; P=0.04).

CONCLUSION

This systematic review and meta-analysis provide evidence that NPWT is superior to conventional treatment for patients with DSWI following cardiovascular surgery.

Vacuum-assisted closure therapy for the management of deep sternal wound complications: A systematic review and meta-analysis

BACKGROUND

Vacuum-assisted closure (VAC) therapy has become a popular treatment option for wound healing. The aim of this meta-analysis was to assess the use of VAC therapy as a bridge before the definitive treatment for the management of deep sternal wound complications.

METHODS

A systematic literature review and meta-analysis were performed in PubMed and Embase. Outcomes of interest included mortality, treatment failure, length of hospital stay (LOS), length of intensive care unit (ICU) stay and cost of treatment.

RESULTS

Twenty-two studies involving 1980 patients were included in the quantitative synthesis of this meta-analysis. Patients treated with VAC had significantly lower overall mortality [1738 patients; Risk ratio [RR] = 0.36 (95% confidence interval [CI]: 0.25, 0.51)], treatment failure [1210 patients; RR = 0.26 (95% CI: 0.19, 0.37)], LOS [498 patients; (standard mean difference = -0.44 (95% CI: -0.81, -0.07)] and ICU stay [309 patients; (standard mean difference = -0.34 (95% CI: -0.67, -0.01)] compared to that of non-VAC patients. VAC therapy was associated with reduced cost of treatment per patient compared with that of non-VAC therapies (reductions of 3600 USD, 6000 USD and 8983 USD in the reported studies).

CONCLUSIONS

VAC therapy as an adjunct in the definitive treatment of patients with deep sternal wound complications was associated with lower mortality, treatment failure, LOS, ICU stay and cost of treatment when compared with a non-VAC approach. Randomised controlled trials would be essential to confirm these findings.

Postoperative complications associated with coronary artery bypass graft surgery and their therapeutic interventions

Coronary artery disease is one of the commonest surgery demanding cardiovascular diseases. Coronary artery bypass graft surgery is practiced all over the world for the treatment of coronary artery disease. Systemic trauma during the surgery is associated with a wide range of complications, some of which are fatal. Preoperative risk factors such as age, previous illness and obesity are common predictors of these adverse events. Advances in therapeutic medicine have allowed timely treatment of these adverse events and co-morbidities. This review summarizes some of the most occurring complications associated with coronary artery bypass graft and corresponding treatment options.

Application of SPY Angiography in the Management of a Chronic Sternal Wound

The SPY angiography system has several surgical uses. Often, surgeons may experience difficult cases in which the viability and perfusion of tissue is questioned. By using the SPY angiography system intraoperatively, this system may provide additional information allowing the surgeon to make calculated real-time decisions which may lead to improved patient outcomes. This study describes a case of a chronic sternal wound treated with reconstruction using intraoperative SPY angiography. Adequate perfusion of the flap was determined via SPY angiography intraoperatively. The flap was thereafter successfully utilized to cover the chronic wound. The patient was followed postoperatively with progression of wound closure. Sternal wounds often pose a complex problem for patients and physicians. The use of intraoperative SPY angiography provided critical information to the operating team allowing for the successful identification of a viable flap. The use of SPY angiography provided the patient an opportunity to achieve a successful outcome and reduced the risk of skin necrosis or reoperation.

Steroids in cardiac surgery trial: a substudy of surgical site infections

PURPOSE

Postoperative infection, particularly in cardiac surgery, results in significant morbidity, mortality, and healthcare cost. Identification of novel predictors of postoperative infection can target high-risk populations for prophylactic intervention.

METHODS

Steroids in cardiac surgery (SIRS) was a multi-centre randomized-controlled trial assessing intraoperative administration of methylprednisone during cardiac surgery, which enrolled 7,507 patients across 80 centres in 18 countries. It demonstrated that administration of steroids had no effect on mortality or major morbidity after cardiac surgery. Our primary objective was to identify risk factors for postoperative surgical site infections using SIRS participants as a cohort. We excluded patients who did not undergo surgery, died intraoperatively, or died within 48 hr of the operation. Patients were assessed for development of "surgical site infection" over the first 30 days postoperatively. Using theoretical and previously identified risk factors, we used forward stepwise entry to create a binary logistic regression model.

RESULTS

Follow-up at 30 days was complete for all patients; 7,406 were included in the cohort. Surgical site infection occurred in 180 (4.8%) and 184 (5.0%) of patients in the placebo and steroid arms respectively. Significant risk factors (P < 0.05 level) included: diabetes managed with insulin (adjusted odds ratio [aOR]: 1.55; 95% confidence interval [CI] 1.13 to 2.12), oral hypoglycemics (aOR 1.60; 95% CI 1.18 to 2.16), or diet (aOR 1.81; 95% CI 1.16 to 2.83), female sex (aOR 1.34; 95% CI 1.05 to 1.71), renal failure with (aOR 2.03; 95% CI 1.06 to 3.91), and without (aOR 1.50; 95% CI 1.04 to 2.14) dialysis, > 96 min cardiopulmonary bypass (CPB) time (aOR 1.84; 95% CI 1.44 to 2.35), body mass index (BMI) < 22.3 (aOR 0.44; 95% CI 0.28 to 0.71) or > 30 (aOR 1.49; 95% CI 1.17 to 1.89), peak intensive care unit blood glucose (aOR 1.02 per mmol·L^-1; 95% CI 1.00 to 1.04), and coronary artery bypass grafting (CABG) operation type (aOR 2.59; 95% CI 1.87 to 3.59).

CONCLUSIONS

Patients undergoing CABG, requiring longer CPB, with higher BMI, or with diabetes, are at elevated risk of surgical site infection. Strategies to mitigate this risk warrant further investigation.

Deep sternal wound infection after cardiac surgery in the Chinese population: a single-centre 15-year retrospective study

Background

Deep sternal wound infection (DSWI) is a severe complication following cardiac surgery. A retrospective study was implemented to determine the risks and clinical characteristics of DSWI after cardiac operation in the Chinese population.

Methods

We analysed 7,944 consecutive patients who underwent cardiac surgery via median sternotomy from January 2002 to December 2016 at our institution. Multiple logistic regression analysis was used to identify risk factors for DSWI.

Results

A total of 106 patients (1.33%) suffered from DSWI; significant risk factors included body mass index (BMI) (P=0.02; OR=1.08; 95% CI: 1.01-1.16) and reoperation (P<0.01; OR=5.93; 95% CI: 2.88-12.25). The most common bacterium involved in DSWI was staphylococcus aureus (23%). Among all DSWI patients, the overall survival rate of the group treated with flap reconstruction was significantly higher than that in the group treated with intravenous antibiotics and sternal debridement (87% vs. 59%, P=0.01).

Conclusions

DSWI was associated with several risk factors. Effective intervention strategies could improve the outcome of patients undergoing cardiac surgery.

Is Diabetes Mellitus a Risk Factor for Poor Outcomes after Left Ventricular Assist Device Placement?

Diabetes mellitus is associated with adverse outcomes in patients with cardiovascular diseases, including heart failure. Left ventricular assist devices (LVADs) are increasingly used as life-saving therapy for advanced heart failure. The effects of pre-LVAD diabetes on long-term outcomes after LVAD implantation are not well understood. In this study, we retrospectively evaluated the effect of existing diabetes on post-LVAD outcomes. Data on 288 LVAD recipients from 2006 through 2013 were reviewed. Patients were stratified in accordance with their histories of diabetes. Baseline demographic, laboratory, hemodynamic, and echocardiographic information before LVAD placement were reviewed, together with the post-LVAD incidence of major adverse outcomes. Kaplan-Meier analysis and Cox regression analysis were performed. Our cohort comprised 122 patients with diabetes and 166 patients without. The mean glycosylated hemoglobin A_1c level in the diabetes group was 7.4% ± 1.6%. Diabetic patients at baseline had a more adverse medical profile than did nondiabetic patients. There were no differences in major outcomes between the 2 groups other than a higher incidence of hemolysis in the diabetes group: 12 (10%) vs 5 (3%); P=0.02. There was no difference in survival outcomes between the groups. Diabetic patients did not have worse survival or more adverse outcomes than did nondiabetic patients in this study, perhaps because of improved diabetes control, or improvement in biochemical derangements after normalization of cardiac output with LVAD therapy. A diagnosis of diabetes was an independent predictor of hemolysis. Further studies to evaluate the link between hemolysis and diabetes are indicated.

Classification of hospital acquired complications using temporal clinical information from a large electronic health record

Hospital acquired complications (HACs) are serious problems affecting modern day healthcare institutions. It is estimated that HACs result in an approximately 10% increase in total inpatient hospital costs across US hospitals. With US hospital spending totaling nearly $900 billion per annum, the damages caused by HACs are no small matter. Early detection and prevention of HACs could greatly reduce strains on the US healthcare system and improve patient morbidity & mortality rates. Here, we describe a machine-learning model for predicting the occurrence of HACs within five distinct categories using temporal clinical data. Using our approach, we find that at least $10 billion of excessive hospital costs could be saved in the US alone, with the institution of effective preventive measures. In addition, we also identify several keystone features that demonstrate high predictive power for HACs over different time periods following patient admission. The classifiers and features analyzed in this study show high promise of being able to be used for accurate prediction of HACs in clinical settings, and furthermore provide novel insights into the contribution of various clinical factors to the risk of developing HACs as a function of healthcare system exposure.

Incidence of Deep Sternal Wound Infection in Diabetic Patients Undergoing Off-Pump Skeletonized Internal Thoracic Artery Grafting

OBJECTIVES

To evaluate the impact of skeletonized bilateral or single internal thoracic artery (ITA) grafting on the risk of deep sternal wound infection (DSWI) in diabetic patients undergoing off-pump coronary artery bypass grafting (OPCAB).

MATERIALS AND METHODS

A total of 803 diabetic patients undergoing OPCAB surgery from January 2010 to December 2014 were enrolled into this study and assigned to the pSITA group (patients undergoing pedicled single ITA grafting, n = 362), the sSITA group (skeletonized single ITA grafting, n = 295), or the sBITA group (skeletonized bilateral ITA grafting, n = 146). The primary end point was the diagnosis of a DSWI.

RESULTS

Eighteen patients developed postoperative DSWI, with an incidence of 2.2%. Patients in the sSITA group had a significantly lower incidence of DSWI than those in the pSITA group (1.0 vs. 3.6%, p = 0.0408). In multivariate logistic regression analysis, the risk of DSWI in the sSITA group was 0.41 times that in the pSITA group.

CONCLUSIONS

sSITA grafting lowered the risk of DSWI in diabetic patients undergoing OPCAB surgery compared to pSITA grafting. Multicenter clinical trials involving larger sample sizes are needed to determine the merit of pSITA grafting in reducing the risk of DSWI following OPCAB surgery.

Are two really always better than one? Results, concerns and controversies in the use of bilateral internal thoracic arteries for coronary artery bypass grafting in the elderly: a systematic review and meta-analysis

INTRODUCTION

Bilateral internal thoracic artery grafting appears to be the preferred method to achieve durable long-term coronary artery revascularization. However, data reporting the benefit of this technique in the elderly is very conflicting.

METHOD

We performed a systematic review of available literature (till November 2014) using multiple databases to identify studies comparing clinical events in patients undergoing coronary artery bypass grafting using either a single or double internal thoracic artery in the elderly. While early mortality was the primary end-point of inclusion, other adverse events compared were sternal wound infection (deep and superficial), stroke and peri-operative myocardial infarction. Individual and pooled odd's ratios were calculated using the Mantel-Haenzel method (random effect model); sensitivity analysis was performed. Results are presented using 95% confidence intervals.

RESULT

Nine retrospective studies (4479 BITA, 7733 LITA patients) fulfilled search criteria. Deep sternal wound infection was significantly higher after BITA harvest [OR 1.86 (1.3-2.5); I(2) = 0%; p < 0.01]. Early mortality (BITA 3.6% vs SITA 3.1%; p = 0.86), stroke [OR 0.7(0.4-1.1); p = 0.1], and peri-operative myocardial infarction (BITA 4.3% vs SITA 2.3%; p = 0.1) were comparable in both cohorts. Long-term survival favored the BITA cohort in two propensity matched studies.

CONCLUSION

The incidence of deep sternal wound infection may be significantly higher after the harvest of both internal thoracic arteries in the elderly. While other post-operative adverse events are comparable, data regarding the long-term survival advantage in this cohort is conflicting. Hence, the use of both internal thoracic arteries in this age group needs to be invidualized.