Impact of the COVID-19 pandemic on incidence and severity of acute appendicitis: a comparison between 2019 and 2020.

BACKGROUND: During the COVID-19 pandemic, a decrease in the number of patients presenting with acute appendicitis was observed. It is unclear whether this caused a shift towards more complicated cases of acute appendicitis. We compared a cohort of patients diagnosed with acute appendicitis during the 2020 COVID-19 pandemic with a 2019 control cohort. METHODS: We retrospectively included consecutive adult patients in 21 hospitals presenting with acute appendicitis in a COVID-19 pandemic cohort (March 15 - April 30, 2020) and a control cohort (March 15 - April 30, 2019). Primary outcome was the proportion of complicated appendicitis. Secondary outcomes included prehospital delay, appendicitis severity, and postoperative complication rates. RESULTS: The COVID-19 pandemic cohort comprised 607 patients vs. 642 patients in the control cohort. During the COVID-19 pandemic, a higher proportion of complicated appendicitis was seen (46.9% vs. 38.5%; p = 0.003). More patients had symptoms exceeding 24 h (61.1% vs. 56.2%, respectively, p = 0.048). After correction for prehospital delay, presentation during the first wave of the COVID-19 pandemic was still associated with a higher rate of complicated appendicitis. Patients presenting > 24 h after onset of symptoms during the COVID-19 pandemic were older (median 45 vs. 37 years; p = 0.001) and had more postoperative complications (15.3% vs. 6.7%; p = 0.002). CONCLUSIONS: Although the incidence of acute appendicitis was slightly lower during the first wave of the 2020 COVID-19 pandemic, more patients presented with a delay and with complicated appendicitis than in a corresponding period in 2019. Spontaneous resolution of mild appendicitis may have contributed to the increased proportion of patients with complicated appendicitis. Late presenting patients were older and experienced more postoperative complications compared to the control cohort.

Topical antimicrobial treatment of mesh for the reduction of surgical site infections after hernia repair: a systematic review and meta-analysis.

PURPOSE: Use of mesh is essential in hernia repair. A common complication after hernia repair is surgical site infection (SSI), which poses a risk in spreading to the mesh, possibly causing mesh infection. Topical antimicrobial pretreatment of mesh may potentially reduce SSI risk in hernia repair and has shown promising results in in vitro and in vivo studies. Clinical evidence, however, is more important. This systematic review aims to provide an overview of available clinical evidence for antimicrobial pretreated mesh in hernia repair surgery to reduce SSI. METHODS: We report in accordance with PRISMA guidelines. CENTRAL, EMBASE, CINAHL and PubMed were searched up to October 2023 for studies that investigated the use of antimicrobial pretreated mesh on SSI incidence in adults undergoing hernia repair. The primary outcome was SSI incidence. We also collected data on pathogen involvement, hernia recurrence, and mesh infection. A meta-analysis on SSI risk and GRADE-assessment was performed of eligible studies. RESULTS: We identified 11 eligible studies (n = 2660 patients); 5 randomized trials and 6 cohort studies. Investigated interventions included pre-coated mesh, antibiotic carriers, mesh soaked or irrigated with antibiotic or antiseptic solution. Meta-analysis showed no significant reduction in SSI for antibiotic pretreated polypropylene mesh (RR 0.76 [95% CI 0.27; 2.09]; I2 50%). CONCLUSION: Data on topical mesh pretreatment to reduce SSI risk after hernia repair is limited. Very low certainty evidence from randomized trials in hernia repair surgery shows no significant benefit for antibiotic mesh pretreatment for SSI reduction, but data are imprecise due to optimal information size not being met.

Incisional Wound Irrigation for the Prevention of Surgical Site Infection: A Systematic Review and Network Meta-Analysis.

Importance: Surgical site infections (SSIs) are common postoperative complications and associated with significant morbidity, mortality, and costs. Prophylactic intraoperative incisional wound irrigation is used to reduce the risk of SSIs, and there is great variation in the type of irrigation solutions and their use. Objective: To compare the outcomes of different types of incisional prophylactic intraoperative incisional wound irrigation for the prevention of SSIs in all types of surgery. Data Sources: PubMed, Embase, CENTRAL, and CINAHL databases were searched up to June 12, 2023. Study Selection: Included in this study were randomized clinical trials (RCTs) comparing incisional prophylactic intraoperative incisional wound irrigation with no irrigation or comparing irrigation using different types of solutions, with SSI as a reported outcome. Studies investigating intracavity lavage were excluded. Data Extraction and Synthesis: This systematic review and network meta-analysis is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Two reviewers independently extracted the data and assessed the risk of bias within individual RCTs using the Cochrane Risk of Bias 2 tool and the certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation framework. A frequentist network meta-analysis was conducted, and relative risks (RRs) with corresponding 95% CIs were reported. Main Outcome and Measure: The primary study outcome was SSI. Results: A total of 1587 articles were identified, of which 41 RCTs were included in the systematic review, with 17 188 patients reporting 1328 SSIs, resulting in an overall incidence of 7.7%. Compared with no irrigation, antiseptic solutions (RR, 0.60; 95% CI, 0.44-0.81; high level of certainty) and antibiotic solutions (RR, 0.46; 95% CI, 0.29-0.73; low level of certainty) were associated with a beneficial reduction in SSIs. Saline irrigation showed no statistically significant difference compared with no irrigation (RR, 0.83; 95% CI, 0.63-1.09; moderate level of certainty). Conclusions and Relevance: This systematic review and network meta-analysis found high-certainty evidence that prophylactic intraoperative incisional wound irrigation with antiseptic solutions was associated with a reduction in SSIs. It is suggested that the use of antibiotic wound irrigation be avoided due to the inferior certainty of evidence for its outcome and global antimicrobial resistance concerns.

Incisional negative pressure wound therapy for the prevention of surgical site infection: an up-to-date meta-analysis and trial sequential analysis.

Background: The evidence on prophylactic use of negative pressure wound therapy on primary closed incisional wounds (iNPWT) for the prevention of surgical site infections (SSI) is confusing and ambiguous. Implementation in daily practice is impaired by inconsistent recommendations in current international guidelines and published meta-analyses. More recently, multiple new randomised controlled trials (RCTs) have been published. We aimed to provide an overview of all meta-analyses and their characteristics; to conduct a new and up-to-date systematic review and meta-analysis and Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessment; and to explore the additive value of new RCTs with a trial sequential analysis (TSA). Methods: PubMed, Embase and Cochrane CENTRAL databases were searched from database inception to October 24, 2022. We identified existing meta-analyses covering all surgical specialties and RCTs studying the effect of iNPWT compared with standard dressings in all types of surgery on the incidence of SSI, wound dehiscence, reoperation, seroma, hematoma, mortality, readmission rate, skin blistering, skin necrosis, pain, and adverse effects of the intervention. We calculated relative risks (RR) with corresponding 95% confidence intervals (CI) using a Mantel-Haenszel random-effects model. We assessed publication bias with a comparison-adjusted funnel plot. TSA was used to assess the risk of random error. The certainty of evidence was evaluated using the Cochrane Risk of Bias-2 (RoB2) tool and GRADE approach. This study is registered with PROSPERO, CRD42022312995. Findings: We identified eight previously published general meta-analyses investigating iNPWT and compared their results to present meta-analysis. For the updated systematic review, 57 RCTs with 13,744 patients were included in the quantitative analysis for SSI, yielding a RR of 0.67 (95% CI: 0.59-0.76, I2 = 21%) for iNPWT compared with standard dressing. Certainty of evidence was high. Compared with previous meta-analyses, the RR stabilised, and the confidence interval narrowed. In the TSA, the cumulative Z-curve crossed the trial sequential monitoring boundary for benefit, confirming the robustness of the summary effect estimate from the meta-analysis. Interpretation: In this up-to-date meta-analysis, GRADE assessment shows high-certainty evidence that iNPWT is effective in reducing SSI, and uncertainty is less than in previous meta-analyses. TSA indicated that further trials are unlikely to change the effect estimate for the outcome SSI; therefore, if future research is to be conducted on iNPWT, it is crucial to consider what the findings will contribute to the existing robust evidence. Funding: Dutch Association for Quality Funds Medical Specialists.

Efficacy of different preoperative skin antiseptics on the incidence of surgical site infections: a systematic review, GRADE assessment, and network meta-analysis.

BACKGROUND: Surgical site infection (SSI) is the most common postoperative complication and substantially increases health-care costs. Published meta-analyses and international guidelines differ with regard to which preoperative skin antiseptic solution and concentration has the highest efficacy. We aimed to compare the efficacy of different skin preparation solutions and concentrations for the prevention of SSIs, and to provide an overview of current guidelines. METHODS: This systematic review and network meta-analysis compared different preoperative skin antiseptics in the prevention of SSIs in adult patients undergoing surgery of any wound classification. We searched for randomised controlled trials (RCTs) in MEDLINE, Embase, and Cochrane CENTRAL, published up to Nov 23, 2021, that directly compared two or more antiseptic agents (ie, chlorhexidine, iodine, or olanexidine) or concentrations in aqueous and alcohol-based solutions. We excluded paediatric, animal, and non-randomised studies, and studies not providing standard preoperative intravenous antibiotic prophylaxis. Studies with no SSIs in both groups were excluded from the quantitative analysis. Two reviewers screened and reviewed eligible full texts and extracted data. The primary outcome was the occurrence of SSI (ie, superficial, deep, and organ space). We conducted a frequentist random effects network meta-analysis to estimate the network effects of the skin preparation solutions on the prevention of SSIs. A risk-of-bias and Grading of Recommendations, Assessment, Development, and Evaluation assessment were done to determine the certainty of the evidence. This study is registered with PROSPERO, CRD42021293554. FINDINGS: Overall, 2326 articles were identified, 33 studies were eligible for the systematic review, and 27 studies with 17 735 patients reporting 2144 SSIs (overall incidence of 12·1%) were included in the quantitative analysis. Only 2·0-2·5% chlorhexidine in alcohol (relative risk 0·75, 95% CI 0·61-0·92) and 1·5% olanexidine (0·49, 0·26-0·92) significantly reduced the rate of SSIs compared with aqueous iodine. For clean surgery, we found no difference in efficacy between different concentrations of chlorhexidine in alcohol. Seven RCTs were at high risk of bias, 24 had some concerns, and two had low risk of bias. Heterogeneity across the studies was moderate (I2=27·5%), and netsplitting did not show inconsistencies between direct and indirect comparisons. Five of ten studies that mentioned adverse events related to the skin preparation solutions reported no adverse events, and five reported a total of 56 mild events (mainly erythema, pruritus, dermatitis, skin irritation, or mild allergic symptoms); none reported a substantial difference in adverse events between groups. INTERPRETATION: For adult patients undergoing a surgical procedure of any wound classification, skin preparation using either 2·0-2·5% chlorhexidine in alcohol or 1·5% olanexidine is most effective in the prevention of SSIs. For clean surgery, no specific concentration of chlorhexidine in alcohol can be recommended. The efficacy of olanexidine was established by a single randomised trial and further investigation is needed. FUNDING: Dutch Association for Quality Funds Medical Specialists.

Probing myeloid cell dynamics in ischaemic heart disease by nanotracer hot-spot imaging.

Ischaemic heart disease evokes a complex immune response. However, tools to track the systemic behaviour and dynamics of leukocytes non-invasively in vivo are lacking. Here, we present a multimodal hot-spot imaging approach using an innovative high-density lipoprotein-derived nanotracer with a perfluoro-crown ether payload (19F-HDL) to allow myeloid cell tracking by 19F magnetic resonance imaging. The 19F-HDL nanotracer can additionally be labelled with zirconium-89 and fluorophores to detect myeloid cells by in vivo positron emission tomography imaging and optical modalities, respectively. Using our nanotracer in atherosclerotic mice with myocardial infarction, we observed rapid myeloid cell egress from the spleen and bone marrow by in vivo 19F-HDL magnetic resonance imaging. Concurrently, using ex vivo techniques, we showed that circulating pro-inflammatory myeloid cells accumulated in atherosclerotic plaques and at the myocardial infarct site. Our multimodality imaging approach is a valuable addition to the immunology toolbox, enabling the study of complex myeloid cell behaviour dynamically.

PET/MR Imaging of Malondialdehyde-Acetaldehyde Epitopes With a Human Antibody Detects Clinically Relevant Atherothrombosis.

BACKGROUND: Oxidation-specific epitopes (OSEs) are proinflammatory, and elevated levels in plasma predict cardiovascular events. OBJECTIVES: The purpose of this study was to develop novel positron emission tomography (PET) probes to noninvasively image OSE-rich lesions. METHODS: An antigen-binding fragment (Fab) antibody library was constructed from human fetal cord blood. After multiple rounds of screening against malondialdehyde-acetaldehyde (MAA) epitopes, the Fab LA25 containing minimal nontemplated insertions in the CDR3 region was identified and characterized. In mice, pharmacokinetics, biodistribution, and plaque specificity studies were performed with Zirconium-89 (89Zr)-labeled LA25. In rabbits, 89Zr-LA25 was used in combination with an integrated clinical PET/magnetic resonance (MR) system. 18F-fluorodeoxyglucose PET and dynamic contrast-enhanced MR imaging were used to evaluate vessel wall inflammation and plaque neovascularization, respectively. Extensive ex vivo validation was carried out through a combination of gamma counting, near infrared fluorescence, autoradiography, immunohistochemistry, and immunofluorescence. RESULTS: LA25 bound specifically to MAA epitopes in advanced and ruptured human atherosclerotic plaques with accompanying thrombi and in debris from distal protection devices. PET/MR imaging 24 h after injection of 89Zr-LA25 showed increased uptake in the abdominal aorta of atherosclerotic rabbits compared with nonatherosclerotic control rabbits, confirmed by ex vivo gamma counting and autoradiography. 18F-fluorodeoxyglucose PET, dynamic contrast-enhanced MR imaging, and near-infrared fluorescence signals were also significantly higher in atherosclerotic rabbit aortas compared with control aortas. Enhanced liver uptake was also noted in atherosclerotic animals, confirmed by the presence of MAA epitopes by immunostaining. CONCLUSIONS: 89Zr-LA25 is a novel PET radiotracer that may allow noninvasive phenotyping of high-risk OSE-rich lesions.

Polyglucose nanoparticles with renal elimination and macrophage avidity facilitate PET imaging in ischaemic heart disease.

Tissue macrophage numbers vary during health versus disease. Abundant inflammatory macrophages destruct tissues, leading to atherosclerosis, myocardial infarction and heart failure. Emerging therapeutic options create interest in monitoring macrophages in patients. Here we describe positron emission tomography (PET) imaging with 18F-Macroflor, a modified polyglucose nanoparticle with high avidity for macrophages. Due to its small size, Macroflor is excreted renally, a prerequisite for imaging with the isotope flourine-18. The particle's short blood half-life, measured in three species, including a primate, enables macrophage imaging in inflamed cardiovascular tissues. Macroflor enriches in cardiac and plaque macrophages, thereby increasing PET signal in murine infarcts and both mouse and rabbit atherosclerotic plaques. In PET/magnetic resonance imaging (MRI) experiments, Macroflor PET imaging detects changes in macrophage population size while molecular MRI reports on increasing or resolving inflammation. These data suggest that Macroflor PET/MRI could be a clinical tool to non-invasively monitor macrophage biology.