Evaluating the Impact of Cardiopulmonary Bypass Priming Fluids on Bleeding After Pediatric Cardiac Surgery: A Systematic Review and Meta-Analysis.

OBJECTIVES: Cardiopulmonary bypass (CPB) predisposes young children to coagulopathy. The authors evaluated possible effects of CPB priming fluids on perioperative bleeding in pediatric cardiac surgery. DESIGN: Meta-analysis and systematic review of previously published studies. SETTING: Each study was conducted in a surgical center or intensive care unit. PARTICIPANTS: Studies investigating patients <18 years without underlying hematologic disorders were included. INTERVENTIONS: The authors evaluated randomized controlled trials (RCTs) published between 1980 and 2020 on MEDLINE, EMBASE, PubMed, and CENTRAL databases. The primary outcome was postoperative bleeding; secondary endpoints included blood product transfusion, mortality, and safety. MEASUREMENTS AND MAIN RESULTS: Twenty eligible RCTs were analyzed, with a total of 1,550 patients and a median of 66 patients per study (range 20-200). The most frequently assessed intervention was adding fresh frozen plasma (FFP) to the prime (8/20), followed by albumin (5/20), artificial colloids (5/20), and blood-based priming solutions (3/20). Ten studies with 771 patients evaluated blood loss at 24 hours in mL/kg and were included in a meta-analysis. Most of them investigated the addition of FFP to the priming fluid (7/10). No significant difference was found between intervention and control groups, with a mean difference of -0.13 (-2.61 to 2.34), p = 0.92, I2 = 69%. Further study endpoints were described but their reporting was too heterogeneous to be quantitatively analyzed. CONCLUSIONS: This systematic review of current evidence did not show an effect of different CPB priming solutions on 24-hour blood loss. The analysis was limited by heterogeneity within the dataset regarding population, type of intervention, dosing, and the chosen comparator, compromising any conclusions.

The effects of the neonicotinoid imidacloprid on gene expression and DNA methylation in the buff-tailed bumblebee Bombus terrestris.

Neonicotinoids are effective insecticides used on many important arable and horticultural crops. They are nicotinic acetylcholine receptor agonists which disrupt the function of insect neurons and cause paralysis and death. In addition to direct mortality, there are numerous sublethal effects of low doses of neonicotinoids on bees. We hypothesize that some of these large array of effects could be a consequence of epigenetic changes in bees induced by neonicotinoids. We compared whole methylome (BS-seq) and RNA-seq libraries of the brains of buff-tailed bumblebee Bombus terrestris workers exposed to field-realistic doses of the neonicotinoid imidacloprid to libraries from control workers. We found numerous genes which show differential expression between neonicotinoid-treated bees and control bees, but no differentially methylated cytosines in any context. We found CpG methylation to be focused mainly in exons and associated with highly expressed genes. We discuss the implications of our results for future legislation.

The DiPEP study: an observational study of the diagnostic accuracy of clinical assessment, D-dimer and chest x-ray for suspected pulmonary embolism in pregnancy and postpartum.

OBJECTIVE: To identify clinical features associated with pulmonary embolism (PE) diagnosis and determine the accuracy of decision rules and D-dimer for diagnosing suspected PE in pregnant/postpartum women DESIGN: Observational cohort study augmented with additional cases. SETTING: Emergency departments and maternity units at eleven prospectively recruiting sites and maternity units in the United Kingdom Obstetric Surveillance System (UKOSS) POPULATION: 324 pregnant/postpartum women with suspected PE and 198 pregnant/postpartum women with diagnosed PE METHODS: We recorded clinical features, elements of clinical decision rules, D-dimer measurements, imaging results, treatments and adverse outcomes up to 30 days MAIN OUTCOME MEASURES: Women were classified as having PE on the basis of imaging, treatment and adverse outcomes by assessors blind to clinical features and D-dimer. Primary analysis was limited to women with conclusive imaging to avoid work-up bias. Secondary analyses included women with clinically diagnosed or ruled out PE. RESULTS: The only clinical features associated with PE on multivariate analysis were age (odds ratio 1.06; 95% confidence interval 1.01-1.11), previous thrombosis (3.07; 1.05-8.99), family history of thrombosis (0.35; 0.14-0.90), temperature (2.22; 1.26-3.91), systolic blood pressure (0.96; 0.93-0.99), oxygen saturation (0.87; 0.78-0.97) and PE-related chest x-ray abnormality (13.4; 1.39-130.2). Clinical decision rules had areas under the receiver-operator characteristic curve ranging from 0.577 to 0.732 and no clinically useful threshold for decision-making. Sensitivities and specificities of D-dimer were 88.4% and 8.8% using a standard threshold and 69.8% and 32.8% using a pregnancy-specific threshold. CONCLUSIONS: Clinical decision rules and D-dimer should not be used to select pregnant or postpartum women with suspected PE for further investigation. Clinical features and chest x-ray appearances may have counter-intuitive associations with PE in this context. TWEETABLE ABSTRACT: Clinical decision rules and D-dimer are not helpful for diagnosing pregnant/postpartum women with suspected PE.

Graduated Compression Stockings as an Adjunct to Low Dose Low Molecular Weight Heparin in Venous Thromboembolism Prevention in Surgery: A Multicentre Randomised Controlled Trial.

BACKGROUND: The evidence base upon which current global venous thromboembolism (VTE) prevention recommendations have been made is not optimal. The cost of purchasing and applying graduated compression stockings (GCS) in surgical patients is considerable and has been estimated at £63.1 million per year in England alone. OBJECTIVE: The aim was to determine whether low dose low molecular weight heparin (LMWH) alone is non-inferior to a combination of GCS and low dose LMWH for the prevention of VTE. METHODS: The randomised controlled Graduated compression as an Adjunct to Pharmacoprophylaxis in Surgery (GAPS) Trial (ISRCTN 13911492) will randomise adult elective surgical patients identified as being at moderate and high risk of VTE to receive either the current "standard" combined thromboprophylactic LMWH with GCS mechanical thromboprophylaxis, or thromboprophylactic LMWH pharmacoprophylaxis alone. To show non-inferiority (3.5% non-inferiority margin) for the primary endpoint of all VTE within 90 days, 2236 patients are required. Recruitment will be from seven UK centres. Secondary outcomes include quality of life, compliance with stockings and LMWH, overall mortality, and GCS or LMWH related complications (including bleeding). Recruitment commenced in April 2016 with the seven UK centres coming "on-line" in a staggered fashion. Recruitment will be over a total of 18 months. The GAPS trial is funded by the National Institute for Health Research Health Technology Assessment in the UK (14/140/61).

Explant analysis of the Biomet Magnum/ReCap metal-on-metal hip joint.

OBJECTIVES: The high revision rates of the DePuy Articular Surface Replacement (ASR) and the DePuy ASR XL (the total hip arthroplasty (THA) version) have led to questions over the viability of metal-on-metal (MoM) hip joints. Some designs of MoM hip joint do, however, have reasonable mid-term performance when implanted in appropriate patients. Investigations into the reasons for implant failure are important to offer help with the choice of implants and direction for future implant designs. One way to assess the performance of explanted hip prostheses is to measure the wear (in terms of material loss) on the joint surfaces. METHODS: In this study, a coordinate measuring machine (CMM) was used to measure the wear on five failed cementless Biomet Magnum/ReCap/ Taperloc large head MoM THAs, along with one Biomet ReCap resurfacing joint. Surface roughness measurements were also taken. The reason for revision of these implants was pain and/or adverse reaction to metal debris (ARMD) and/or elevated blood metal ion levels. RESULTS: The mean wear rate of the articulating surfaces of the heads and acetabular components of all six joints tested was found to be 6.1 mm3/year (4.1 to 7.6). The mean wear rate of the femoral head tapers of the five THAs was 0.054 mm3/year (0.021 to 0.128) with a mean maximum wear depth of 5.7 µm (4.3 to 8.5). CONCLUSION: Although the taper wear was relatively low, the wear from the articulating surfaces was sufficient to provide concern and was potentially large enough to have been the cause of failure of these joints. The authors believe that patients implanted with the ReCap system, whether the resurfacing prosthesis or the THA, should be closely monitored.Cite this article: S. C. Scholes, B. J. Hunt, V. M. Richardson, D. J. Langton, E. Smith, T. J. Joyce. Explant analysis of the Biomet Magnum/ReCap metal-on-metal hip joint. Bone Joint Res 2017;6:113-122. DOI: 10.1302/2046-3758.62.BJR-2016-0130.R2.

Rivaroxaban limits complement activation compared with warfarin in antiphospholipid syndrome patients with venous thromboembolism.

Essentials Complement activation has a pathogenic role in thrombotic antiphospholipid syndrome (APS). Coagulation proteases such as factor Xa can activate complement proteins. Complement activation markers were elevated in anticoagulated thrombotic APS patients. Complement activation decreased in APS patients switching from warfarin to rivaroxaban. SUMMARY: Background Complement activation may play a major role in the pathogenesis of thrombotic antiphospholipid syndrome (APS). Coagulation proteases such as factor Xa can activate complement proteins. Aims To establish whether rivaroxaban, a direct factor Xa inhibitor, limits complement activation compared with warfarin in APS patients with previous venous thromboembolism (VTE). Methods A total of 111 APS patients with previous VTE, on warfarin target INR 2.5, had blood samples taken at baseline and at day 42 after randomization in the RAPS (Rivaroxaban in Antiphospholipid Syndrome) trial. Fifty-six patients remained on warfarin and 55 switched to rivaroxaban. Fifty-five normal controls (NC) were also studied. Markers of complement activation (C3a, C5a, terminal complement complex [SC5b-9] and Bb fragment) were assessed. Results APS patients had significantly higher complement activation markers compared with NC at both time-points irrespective of the anticoagulant. There were no differences between the two patient groups at baseline, or patients remaining on warfarin at day 42. In 55 patients randomized to rivaroxaban, C3a, C5a and SC5b-9 were lower at day 42 (median (ng mL-1 ) [confidence interval] 64 [29-125] vs. 83 [35-147], 9 [2-15] vs. 12 [4-18] and 171 [56-245] vs. 201 [66-350], respectively) but levels of Bb fragment were unchanged. There were no correlations between rivaroxaban levels and complement activation markers. Conclusions APS patients with previous VTE on warfarin exhibit increased complement activation, which is likely to occur via the classical pathway and is decreased by rivaroxaban administration. Rivaroxaban may therefore potentially provide an additional benefit to its anticoagulant effect in this patient group by limiting complement activation.

Risk of symptomatic venous thromboembolism following emergency appendicectomy in adults.

BACKGROUND: Appendicectomy is the commonest intra-abdominal emergency surgical procedure, and little is known regarding the magnitude and timing of the risk of venous thromboembolism (VTE) after surgery. This study aimed to determine absolute and relative rates of symptomatic VTE following emergency appendicectomy. METHODS: A cohort study was undertaken using linked primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care data of patients who had undergone emergency appendicectomy from 2001 to 2011. Crude rates and adjusted incidence rate ratios (IRRs) for VTE were calculated using Poisson regression, compared with baseline risk in the year before appendicectomy. RESULTS: A total of 13 441 patients were identified, of whom 56 (0·4 per cent) had a VTE in the first year after surgery. The absolute rate of VTE was highest during the in-hospital period, with a rate of 91·29 per 1000 person-years, which was greatest in those with a length of stay of 7 days or more (267·12 per 1000 person-years). This risk remained high after discharge, with a 19·1- and 6·6-fold increased risk of VTE in the first and second months respectively after discharge, compared with the year before appendicectomy (adjusted IRR: month 1, 19·09 (95 per cent c.i. 9·56 to 38·12); month 2, 6·56 (2·62 to 16·44)). CONCLUSION: The risk of symptomatic VTE following appendicectomy is relatively high during the in-hospital admission and remains increased after discharge. Trials of extended thromboprophylaxis are warranted in patients at particularly high risk.

The impact of hydroxychloroquine treatment on pregnancy outcome in women with antiphospholipid antibodies.

BACKGROUND: Antiphospholipid syndrome is defined by the combination of thrombotic events and/or obstetric morbidity in patients who have tested positive persistently for antiphospholipid antibodies. With good treatment, approximately 70% of pregnant women with antiphospholipid syndrome will deliver a viable live infant. However, current management does not prevent all maternal, fetal, and neonatal complications of antiphospholipid syndrome. OBJECTIVES: This observational, retrospective, single-center cohort study aimed to assess pregnancy outcome in women with antiphospholipid antibodies who were treated with hydroxychloroquine in addition to conventional treatment during pregnancy. STUDY DESIGN: One-hundred seventy pregnancies in 96 women with persistent antiphospholipid antibodies were analyzed: (1) 51 pregnancies that occurred in 31 women were treated with hydroxychloroquine for at least 6 months before pregnancy, and the therapy continued throughout gestation (group A); (2) 119 pregnancies that occurred in 65 women with antiphospholipid antibodies that were not treated with hydroxychloroquine were included as controls (group B). RESULTS: Hydroxychloroquine-treatment was associated with a higher rate of live births (67% group A vs 57% group B; P = .05) and a lower prevalence of antiphospholipid antibodies-related pregnancy morbidity (47% group A vs 63% B; P = .004). The association of hydroxychloroquine with a lower rate of any complication in pregnancy was confirmed after multivariate analysis (odds ratio, 2.2; 95% confidence interval, 1.2-136; P = .04). Fetal losses at >10 weeks of gestation (2% vs 11%; P = .05) and placenta-mediated complications (2% vs 11%; P = .05) were less frequent in group A than group B. Pregnancy duration was longer in group A than group B (27.6 [6-40] vs 21.5 [6-40] weeks; P = .03). There was a higher rate of spontaneous vaginal labor in hydroxychloroquine-treated women compared with group B (37.3% vs 14.3%; P = .01). CONCLUSIONS: Despite the heterogeneity in the 2 groups in terms of systemic lupus erythematosus prevalence and previous pregnancy history, our results support the concept that women with antiphospholipid antibodies may benefit from treatment with hydroxychloroquine during pregnancy to improve pregnancy outcome. The addition of hydroxychloroquine to conventional treatment is worthy of further assessment in a proper designed randomized controlled trial.

A critical appraisal of point-of-care coagulation testing in critically ill patients.

Derangement of the coagulation system is a common phenomenon in critically ill patients, who may present with severe bleeding and/or conditions associated with a prothrombotic state. Monitoring of this coagulopathy can be performed with conventional coagulation assays; however, point-of-care tests have become increasingly attractive, because not only do they yield a more rapid result than clinical laboratory testing, but they may also provide a more complete picture of the condition of the hemostatic system. There are many potential areas of study and applications of point-of-care hemostatic testing in critical care, including patients who present with massive blood loss, patients with a hypercoagulable state (such as in disseminated intravascular coagulation), and monitoring of antiplatelet treatment for acute arterial thrombosis, mostly acute coronary syndromes. However, the limitations of near-patient hemostatic testing has not been fully appreciated, and are discussed here. The currently available evidence indicates that point-of-care tests may be applied to guide appropriate blood product transfusion and the use of hemostatic agents to correct the hemostatic defect or to ameliorate antithrombotic treatment. Disappointingly, however, only in cardiac surgery is there adequate evidence to show that application of near-patient thromboelastography leads to an improvement in clinically relevant outcomes, such as reductions in bleeding-related morbidity and mortality, and cost-effectiveness. More research is required to validate the utility and cost-effectiveness of near-patient hemostatic testing in other areas, especially in traumatic bleeding and postpartum hemorrhage.

Variation in the risk of venous thromboembolism following colectomy.

BACKGROUND: Guidelines recommend extended thromboprophylaxis following colectomy for malignant disease, but not for non-malignant disease. The aim of this study was to determine absolute and relative rates of venous thromboembolism (VTE) following colectomy by indication, admission type and time after surgery. METHODS: A cohort study of patients undergoing colectomy in England was undertaken using linked primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care data (2001-2011). Crude rates and adjusted hazard ratios (HRs) were calculated for the risk of first VTE following colectomy using Cox regression analysis. RESULTS: Some 12,388 patients were identified; 312 (2·5 per cent) developed VTE after surgery, giving a rate of 29·59 (95 per cent c.i. 26·48 to 33·06) per 1000 person-years in the first year after surgery. Overall rates were 2·2-fold higher (adjusted HR 2·23, 95 per cent c.i. 1·76 to 2·50) for emergency compared with elective admissions (39·44 versus 25·78 per 1000 person-years respectively). Rates of VTE were 2·8-fold higher in patients with malignant disease versus those with non-malignant disease (adjusted HR 2·84, 2·04 to 3·94). The rate of VTE was highest in the first month after emergency surgery, and declined from 121·68 per 1000 person-years in the first month to 25·65 per 1000 person-years during the rest of the follow-up interval. Crude rates of VTE were similar for malignant and non-malignant disease (114·76 versus 120·98 per 1000 person-years respectively) during the first month after emergency surgery. CONCLUSION: Patients undergoing emergency colectomy for non-malignant disease have a similar risk of VTE as patients with malignant disease in the first month after surgery.

Maximising the diagnostic potential of APTT-based screening assays for activated protein C resistance.

INTRODUCTION: Activated protein C resistance (APC-R) due to FV Leiden is the most common hereditary thrombophilia. Rarer FV mutations can also confer APC-R, and acquired APC-R is encountered in a number of conditions. APC-R screening with clotting tests is common, yet they are prone to interferences and elevated baseline clotting times can invalidate testing. METHODS: APTT-based classic APC-R (CAPC-R) screening, and modified screening (MAPC-R) employing dilution in FV-deficient plasma were performed on an automated analyser. Baseline clotting times and APC-R ratios of 1340 patients being screened for hereditary and acquired thrombophilia were assessed for analytical and diagnostic validity. RESULTS: Most patients (1117/1340) had normal baseline clotting times, and in 270 of these cases, this was despite the presence of a lupus anticoagulant (LA). FV Leiden was genetically confirmed in all patients with reduced CAPC-R and MAPC-R ratios. A subgroup with normal CAPC-R but reduced MAPC-R also identified FV Leiden, but also other patients with minimally reduced MAPC-R ratios not due to FV Leiden. Reduced CAPC-R and normal modified APC-R identified possible acquired APC-R in 49 patients. LA-positive patients with elevated baseline clotting times did not affect distinction between APC-R and normality, although therapeutic anticoagulation did invalidate CAPC-R, and occasionally MAPC-R too. CONCLUSIONS: Many departments only screen with MAPC-R to detect just FV mutations. Concurrent performance of CAPC-R and MAPC-R increases diagnostic capability by detecting acquired APC-R. Elevated baseline clotting times can invalidate APC-R ratios, although prolongation by LA alone may not.

Rivaroxaban in antiphospholipid syndrome (RAPS) protocol: a prospective, randomized controlled phase II/III clinical trial of rivaroxaban versus warfarin in patients with thrombotic antiphospholipid syndrome, with or without SLE.

INTRODUCTION: The current mainstay of the treatment of thrombotic antiphospholipid syndrome (APS) is long-term anticoagulation with vitamin K antagonists (VKAs) such as warfarin. Non-VKA oral anticoagulants (NOACs), which include rivaroxaban, have been shown to be effective and safe compared with warfarin for the treatment of venous thromboembolism (VTE) in major phase III prospective, randomized controlled trials (RCTs), but the results may not be directly generalizable to patients with APS. AIMS: The primary aim is to demonstrate, in patients with APS and previous VTE, with or without systemic lupus erythematosus (SLE), that the intensity of anticoagulation achieved with rivaroxaban is not inferior to that of warfarin. Secondary aims are to compare rates of recurrent thrombosis, bleeding and the quality of life in patients on rivaroxaban with those on warfarin. METHODS: Rivaroxaban in antiphospholipid syndrome (RAPS) is a phase II/III prospective non-inferiority RCT in which eligible patients with APS, with or without SLE, who are on warfarin, target international normalized ratio (INR) 2.5 for previous VTE, will be randomized either to continue warfarin (standard of care) or to switch to rivaroxaban. Intensity of anticoagulation will be assessed using thrombin generation (TG) testing, with the primary outcome the percentage change in endogenous thrombin potential (ETP) from randomization to day 42. Other TG parameters, markers of in vivo coagulation activation, prothrombin fragment 1.2, thrombin antithrombin complex and D-dimer, will also be assessed. DISCUSSION: If RAPS demonstrates i) that the anticoagulant effect of rivaroxaban is not inferior to that of warfarin and ii) the absence of any adverse effects that cause concern with regard to the use of rivaroxaban, this would provide sufficient supporting evidence to make rivaroxaban a standard of care for the treatment of APS patients with previous VTE, requiring a target INR of 2.5.