Clinical prediction models and risk tools for early detection of patients at risk of surgical site infection and surgical wound dehiscence: a scoping review.

OBJECTIVE: Despite advances in surgical techniques, intraoperative practice and a plethora of advanced wound therapies, surgical wound complications (SWCs), such as surgical site infection (SSI) and surgical wound dehiscence (SWD), continue to pose a considerable burden to the patient and healthcare setting. Predicting those patients at risk of a SWC may give patients and healthcare providers the opportunity to implement a tailored prevention plan or potentially ameliorate known risk factors to improve patient postoperative outcomes. METHOD: A scoping review of the literature for studies which reported predictive power and internal/external validity of risk tools for clinical use in predicting patients at risk of SWCs after surgery was conducted. An electronic search of three databases and two registries was carried out with date restrictions. The search terms included 'prediction surgical site infection' and 'prediction surgical wound dehiscence'. RESULTS: A total of 73 records were identified from the database search, of which six studies met the inclusion criteria. Of these, the majority of validated risk tools were predominantly within the cardiothoracic domain, and targeted morbidity and mortality outcomes. There were four risk tools specifically targeting SWCs following surgery. CONCLUSION: The findings of this review have highlighted an absence of well-developed risk tools specifically for SSI and/or SWD in most surgical populations. This review suggests that further research is required for the development and clinical implementation of rigorously validated and fit-for-purpose risk tools for predicting patients at risk of SWCs following surgery. The ability to predict such patients enables the implementation of preventive strategies, such as the use of prophylactic antibiotics, delayed timing of surgery, or advanced wound therapies following a procedure.

Do in-hospital outcomes of isolated coronary artery bypass grafting vary between male and female octogenarians?

OBJECTIVES: Female gender and advanced age are regarded as independent risk factors for adverse outcomes after isolated coronary artery bypass grafting (CABG). There is paucity of evidence comparing outcomes of CABG between male and female octogenarians. We aimed to analyse in-hospital outcomes of isolated CABG in this cohort. METHODS: All octogenarians that underwent isolated CABG, from January 2000 to October 2017, were included. A retrospective analysis of a prospectively collected cardiac surgery database (PATS; Dendrite Clinical Systems, Oxford, UK) was performed. A propensity score was generated for each patient from a multivariable logistic regression model based on 25 pre-treatment covariates. A total of 156 matching pairs were derived. RESULTS: Five hundred and sixty-seven octogenarians underwent isolated CABG. This included 156 females (mean age 82.1 [SD: 0.9]) and 411 males (mean age 82.4 [SD: 2.1 years]). More males were current smokers (P = 0.002) with renal impairment (P = 0.041), chronic obstructive pulmonary disease (P = 0.048), history of cerebrovascular accident (P = 0.039) and peripheral vascular disease (P = 0.027) while more females had New York Heart Association class 4 (P = 0.02), left ventricular ejection fraction 30-49% (P = 0.038) and left ventricular ejection fraction <30% (P = 0.049). On-pump, CABG was performed in 140 males and 52 females (P = 0.921). There was no difference in in-hospital mortality (5.4% vs 6.4%; P = 0.840), stroke (0.9% vs 1.3%; P = 0.689), need for renal replacement therapy (17.0% vs 13.5%; P = 0.732), pulmonary complications (9.5% vs 8.3%; P = 0.746) and sternal wound infection (2.7% vs 2.6%; P = 0.882). The outcomes were comparable for the propensity-matched cohorts. CONCLUSIONS: No gender difference in outcomes was seen in octogenarians undergoing isolated CABG.

A multicentre review comparing long term outcomes of endoscopic vein harvesting versus open vein harvesting for coronary artery bypass surgery.

Background: Utilisation of the Endoscopic Vein Harvesting (EVH) technique has been increasing for coronary artery bypass grafting (CABG) for the last two decades. Some surgeons remain concerned about the long-term patency of the long saphenous vein harvested endoscopically compared to traditional Open Vein Harvesting (OVH). The aim of this study was to perform a retrospective analysis of the outcomes between EVH and OVH from three UK centres with 10 years follow-up. Methods: 27,024 patients underwent CABG with long saphenous vein harvested by EVH (n=13,794) or OVH (n=13,230) in three UK centres between 2007 and 2019. Propensity modelling was used to calculate the Inverse Probability of Treatment Weights (IPTW). The primary endpoint was mortality from all causes and secondary endpoints were length of hospital stay, postoperative complications, and incidence of repeat coronary re-vascularisation for symptomatic patients. IPTW was used to balance the two intervention groups for baseline and preoperative co-morbidities. Results: Median follow-up time was 4.54 years for EVH and 6.00 years for OVH. Death from any cause occurred in 13.8% of the EVH group versus 20.8% in the OVH group over the follow-up period. The hazard ratio of death (EVH to OVH) was 0.823 (95% CI: 0.767, 0.884). Length of hospital stay was similar between the groups (p=0.86). Post-operative pulmonary complications were more common in EVH vs OVH (14.7% vs. 12.8%, p<0.001), but repeat coronary re-vascularisation was similar between the groups. Conclusions: This large retrospective multicentre analysis indicates that EVH has a lower risk of mortality compared with OVH during the follow-up period of the study. The observed benefits of EVH may outweigh the risks but should be considered on a case-by-case basis. We hope this review gives confidence to other cardiac centres that offering an EVH approach to conduit harvesting does not affect long term patient outcomes.

Use of keyhole vein removal technique has been increasing for coronary artery bypass surgery for last two decades. However, some surgeons remain worried about the quality and long-term effect of the vein tube removed using keyhole method compared to traditional Open Vein Harvesting (OVH). The aim of this study was to perform a retrospective analysis of the outcomes between keyhole and OVH from three UK centres with 10 years follow-up. In total, 27,024 patients underwent coronary artery bypass surgery with long saphenous vein harvested by either keyhole (n=13,794) or OVH (n=13,230) over a period of 2007­2019. The median follow-up time was 4.54 years for keyhole method and 6.00 years for OVH. Death from any cause occurred in 13.8% of the keyhole group versus 20.8% in the OVH group over the follow-up period. In conclusion, the keyhole surgery survival is not as bad as we hypothesised.

Implementing enhanced patient education for surgical site infection prevention in cardiac surgery.

OBJECTIVES: Photo at Discharge (PaD) is a nurse-led discharge strategy for enhanced wound care information for patients and healthcare providers. The purpose of this study is to describe implementation of PaD in three English cardiac centres. METHODS: A prospective, cross-sectional design was used to evaluate implementation fidelity and sustainability of PaD on various geographical settings. RESULTS: Three out of four hospitals (75%) approached agreed to complete surveys on implementation fidelity. Implementing the IT component took an average of 16 months (range 11-21 months). Across the three sites, 474 nursing staff have received training on PaD. Since implementing, a combined total of 9007 patients have received PaD. A 1-month compliance snapshot indicated mean of 96% (range 92-100%). CONCLUSIONS: PaD requires collaborative working, a change in behaviour and a change to the service. Despite these challenges, fidelity and sustainability scores across the sites were high. The findings from this study may help to increase implementation quality and dissemination of PaD.

On-pump and off-pump coronary artery bypass grafting for patients needing at least two grafts: comparative outcomes at 20 years.

OBJECTIVES: Despite evidence from several randomized controlled trials and observational studies validating short-term safety and efficacy of off-pump coronary artery bypass grafting (CABG), concerns persist regarding the impact of off-pump CABG on long-term survival and freedom from reintervention. This persistent scepticism regarding off-pump CABG prompted us to review our practice of CABG over the last 20 years with a view to comparing the impact of off-pump and on-pump CABG on short-term and long-term outcomes in a high-volume off-pump coronary surgery centre. METHODS: We retrospectively analysed prospectively collected data from the Patients Analysis and Tracking System database (Dendrite Clinical Systems, Oxford, UK) for all isolated first-time CABG procedures with at least 2 grafts performed at our institution from January 1996 to September 2017. Over the study period, 5995 off-pump CABG and 4875 on-pump CABG were performed by surgeons with exclusive off-pump and on-pump practices, respectively. Multivariable logistic regression and the Cox model were used to investigate the effect of off-pump versus on-pump procedures on short-term outcomes and long-term survival. Propensity score matching was used to compare the 2 matched groups. RESULTS: Off-pump CABG was associated with a lower risk for 30-day mortality [odds ratio (OR) 0.42, 95% confidence interval (CI) 0.32-0.55; P < 0.001], reintubation/tracheostomy (OR 0.58, 95% CI 0.47-0.72; P < 0.001) and re-exploration for bleeding (OR 0.48, 95% CI 0.37-0.62; P < 0.001). The benefit in terms of operative deaths from off-pump was significant in those with Society of Cardio-Thoracic Surgery logistic EuroSCORE >2 (interaction P = 0.04). When compared with on-pump CABG, off-pump CABG did not significantly reduce the risk of stroke (OR 0.96, 95% CI 0.88-1.12; P = 0.20) and postoperative haemofiltration (OR 0.98, 95% CI 0.86-1.20; P = 0.35). At the median follow-up of 12 years (interquartile range 6-17, max 21), off-pump CABG did not affect late survival [log rank P = 0.24; hazard ratio (HR) 0.95, 95% CI 0.89-1.02] or the need for reintervention (log rank P = 0.12; HR 1.19, 95% CI 0.95-1.48). CONCLUSIONS: This large volume, single-centre study with the longest reported follow-up confirms that off-pump CABG performed by experienced surgeons, who perform only off-pump procedures in a high-volume off-pump coronary surgery centre, is associated with lower risk of operative deaths, fewer postoperative complications and similar 20-year survival and freedom from reintervention rates compared with on-pump CABG.

Short-term clinical outcomes and long-term survival of minimally invasive direct coronary artery bypass grafting.

BACKGROUND: Minimally invasive direct coronary artery bypass (MIDCAB) grafting is regarded as an alternative to conventional coronary artery bypass grafting (CABG) through full sternotomy, particularly for patients with isolated proximal left anterior descending (LAD) artery stenosis deemed unsuitable for percutaneous coronary intervention. However, the technically demanding nature of the procedure and lack of long-term published outcomes have precluded its universal adoption. We report the comparative short-term outcomes and long-term survival of MIDCAB and conventional CABG through full sternotomy for grafting of isolated LAD. METHODS: From February 1996 to October 2017, a total of 668 patients underwent MIDCAB (n=508) and full sternotomy (n=160) CABG for isolated proximal LAD stenosis. Their data were prospectively entered into the institutional cardiac surgery database (Patients Analysis & Tracking System; Dendrite Clinical Systems, Ltd, Oxford, England, United Kingdom) and analyzed retrospectively. Information on patient deaths was obtained from the institutional database and the National General Register Office for all patients. RESULTS: The two groups were comparable with respect to preoperative demographics and risk profile. MIDCAB was associated with longer operative time (177±32 versus 141±12 min; P=0.003). The two groups did not significantly differ with regard to other complications including operative mortality. At a mean follow-up of 12.95±0.47 years, survival was also similar. CONCLUSIONS: This large single centre study with longest follow-up validates the status of MIDCAB as an effective strategy for grafting of LAD. However, it fails to show superiority of the minimally invasive approach compared to conventional CABG through full sternotomy.

Multi-centre prospective internal and external evaluation of the Brompton Harefield Infection Score (BHIS).

BACKGROUND: Previously, we reported that the Brompton Harefield Infection Score (BHIS) accurately predicts surgical site infection (SSI) after coronary artery bypass grafting (CABG). The BHIS was developed using two-centre data and stratifies SSI risk into three groups based on female gender, diabetes or HbA1c > 7.5%, body mass index ≥ 35, left ventricular ejection fraction < 45% and emergency surgery. The purpose of this study was to prospectively evaluate BHIS internally as well as externally. METHODS: Multi-centre prospective evaluation involving three tertiary centres took place between October 2012 and November 2015. SSI was classified using the Public Health England protocol. Receiver operating characteristic (ROC) curves assessed predictive accuracy. RESULTS: Across the four hospital sites, 168 of 4308 (3.9%) CABG patients had a SSI. Categorising the hospitals by BHIS score revealed that 65% of all patients were low risk (BHIS 0-1), 26% were medium risk (BHIS 2-3) and 8% were high risk (BHIS ≥ 4). The area under the ROC curve was in the range of 0.702-0.785. Overall area under the ROC curve was 0.709. CONCLUSIONS: BHIS provides a novel, internally and externally evaluated score for a patient's risk of SSI after CABG. It enables clinicians to focus on strategies to prospectively identify high-risk patients and improve outcomes.

Impact of choice of skin preparation solution in cardiac surgery on rate of surgical site infection: a propensity score matched analysis.

BACKGROUND: Antiseptic skin preparations containing chlorhexidine gluconate and povidone iodine are routinely used to reduce the risk of surgical site infection (SSI). This study assesses the efficacy of two alcohol-based solutions, 2% chlorhexidine-alcohol and 10% povidone iodine-alcohol, on the incidence of cardiac SSI. METHODS: A total of 738 consecutive patients undergoing cardiac surgery had skin preparation with 2% chlorhexidine gluconate in 70% isopropanol (ChloraPrep, BD Ltd, UK) were propensity matched to 738 patients with skin prepared with 10% povidone-iodine in 30% industrial methylated spirit (Videne Alcoholic Tincture, Ecolab Ltd, UK). Continuous, prospective SSI surveillance data were collected for all these patients. A retrospective analysis of prospectively collected perioperative data was performed. RESULTS: The overall rate of SSI was similar in the chlorhexidine-alcohol and povidone-iodine-alcohol groups (3.3% versus 3.8%; P = 0.14; relative risk [RR] = 0.98; 95% confidence interval [CI] = 0.52-1.78). Superficial (1.2% versus 1.8%; P = 0.18; RR = 0.97; 95% CI = 0.48-1.80) and deep incisional (1.2% versus 1.6%; P = 0.24) SSI rates were also similar with 10% povidone-iodine-alcohol being marginally more effective against organ-space infections (0.8% versus 0.4%; P = 0.05; RR = 0.38; 95% CI = 0.20-1.01). CONCLUSION: Our analysis confirms that alcohol-based skin preparation in cardiac surgery with povidone-iodine reduces the incidence of organ-space infections with no significant superiority in preventing incisional SSI compared with chlorhexidine-alcohol.

Retrospective analysis of the Photo at Discharge scheme and readmission for surgical site infection following coronary artery bypass graft surgery.

Background: Surgical site infection (SSI) is a costly and devastating complication of surgery. Many cardiac SSIs develop after the patient leaves hospital, but evidence demonstrating the benefit of patient/carer involvement in the process of monitoring and promptly identifying SSI post-discharge is limited. This study estimates the probability of readmission for SSI for coronary artery bypass graft (CABG) patients receiving the Photo at Discharge (PaD). Methods: Trained personnel undertook continuous, prospective SSI surveillance using Public Health England protocol between January 2013 and December 2016. Baseline covariables were collected for 1747 CABG-only procedures. As a quasi-randomised design, we adjusted for non-random PaD assignment using retrospective propensity score (PS)-matching based on 12 variables of interest, assessed whether the model had been adequately specified and performed an outcomes analysis. Results: A total of 568 patients with PaD were PS-matched with 568 controls. The probabilities of SSI readmission were 0.352 (2/568) and 1.761 (10/568), respectively. The difference in risk of readmission for SSI was significant (relative risk = 0.2, 95% confidence interval = 0.04-0.91; P = 0.04). Conclusion: Findings from this single-centre observation study suggest the PaD is associated with a reduction in CABG readmission for SSI and a further study is warranted to verify the efficacy of this strategy.

Brompton Harefield Infection Score (BHIS): development and validation of a stratification tool for predicting risk of surgical site infection after coronary artery bypass grafting.

OBJECTIVE: Surgical site infection (SSI) following coronary artery bypass grafting (CABG) is a serious complication associated with significant morbidity and mortality. Despite the substantial impact of SSI there is lack of a specific risk stratification tool to predict this complication after CABG. This study was undertaken to develop a specific prognostic scoring system for the development of SSI that could risk-stratify patients undergoing CABG. METHODS: Between January 2009 and June 2012, continuous prospective surveillance data on SSI and a set of 41 variables were collected. Using binary logistic regression analysis we identified independent predictors of SSI. Initially we developed a predictive model in a subset of 769 patients. Dataset was expanded to 4087 cases and a final model and risk score were derived. Calibration of the scores was performed using the Hosmer-Lemeshow test. RESULTS: The model had area under Receiver Operating Characteristic curve of 0.727 (0.827 for preliminary dataset). Baseline risk score incorporated independent predictors of SSI: female gender = 2 (p < 0.0001; RR 2.1), diabetes = 1 (p = 0.0098, RR 1.4) or HbA1c >7.5% = 3 (p < 0.0001; RR 3.4), body mass index ≥35 = 2 (p < 0.0001; RR 2.4), left ventricular ejection fraction < 45% = 1 (p = 0.0255; RR 1.4), and emergency surgery = 2 (p = 0.012; RR 2.4). A risk stratification system, the Brompton & Harefield Infection Score (BHIS) was developed. CONCLUSION: BHIS effectively predicts SSI risk and may help with risk stratification in relation to public reporting and reimbursement as well as targeted prevention strategies in patients undergoing CABG.