Assessing the impact of different heparin dosing regimens for cardiopulmonary bypass on anticoagulation: the HepDOSE pilot study

PURPOSE

It has been suggested that a larger heparin dose during cardiopulmonary bypass (CPB) is associated with reduced perioperative coagulopathy and thromboembolic complications. We investigated the effect of different heparin doses during routine elective cardiac surgery. Our primary outcomes include blood loss and transfusion and secondary outcomes investigate the effects on coagulation biomarkers.

METHODS

In this prospective pilot trial, we allocated 60 patients undergoing cardiac surgery on CPB in a single tertiary cardiac centre into three groups to receive an initial dose of 300, 400, or 500 units (U) per kilogram of intravenous heparin prior to the commencement of CPB. Blood was sampled after induction of anesthesia, at 30 and 60 min of CPB, and three minutes after heparin reversal with protamine. Samples were analyzed for fibrinopeptide A (FPA), fibrinopeptide B (FPB), D-dimer, and thrombin-antithrombin (TAT) complexes. Postoperative blood loss and transfusion was measured for the first 24-hr period after surgery.

RESULTS

The total mean (95% CI) administered heparin dose in the 300 U·kg-1, 400 U·kg-1, and 500 U·kg-1 groups were 39,975 (36,528 to 43,421) U, 43,195 (36,940 to 49,449) U and 47,900 (44,807 to 50,992) U, respectively. There were no statistically significant differences in FPA, FPB or D-dimer levels at the measured time intervals. There was a trend towards lower TAT levels while on CPB with greater heparin dosing, which was statistically significant after the administration of protamine. The clinical significance appears to be negligible, as there is no difference in overall blood loss and amount of packed red blood cell transfusion or other blood product transfusion.

CONCLUSION

This pilot study indicates that, while larger heparin dosing for routine cardiac surgery results in subtle biochemical changes in coagulation, there is no demonstrable benefit in postoperative blood loss or transfusion requirements.

Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study

INTRODUCTION

The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures.

METHODS

In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025.

FINDINGS

Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2-6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5-5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4-10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32-4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23-11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation.

INTERPRETATION

After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification.

FUNDING

UK Research and Innovation and National Institute for Health Research.

D-dimer Release From Livers During Ex Situ Normothermic Perfusion and After In Situ Normothermic Regional Perfusion: Evidence for Occult Fibrin Burden Associated With Adverse Transplant Outcomes and Cholangiopathy

BACKGROUND

Deceased donor livers are prone to biliary complications, which may necessitate retransplantation, and we, and others, have suggested that these complications are because of peribiliary vascular fibrin microthrombi. We sought to determine the prevalence and consequence of occult fibrin within deceased donor livers undergoing normothermic ex situ perfusion (NESLiP) and evaluate a role for fibrinolysis.

METHODS

D-dimer concentrations, products of fibrin degradation, were assayed in the perfusate of 163 livers taken after 2 h of NESLiP, including 91 that were transplanted. These were related to posttransplant outcomes. Five different fibrinolytic protocols during NESLiP using alteplase were evaluated, and the transplant outcomes of these alteplase-treated livers were reviewed.

RESULTS

Perfusate D-dimer concentrations were lowest in livers recovered using in situ normothermic regional perfusion and highest in alteplase-treated livers. D-dimer release from donation after brain death livers was significantly correlated with the duration of cold ischemia. In non-alteplase-treated livers, Cox proportional hazards regression analysis showed that D-dimer levels were associated with transplant survival ( P  = 0.005). Treatment with alteplase and fresh frozen plasma during NESLiP was associated with significantly more D-dimer release into the perfusate and was not associated with excess bleeding postimplantation; 8 of the 9 treated livers were free of cholangiopathy, whereas the ninth had a proximal duct stricture.

CONCLUSIONS

Fibrin is present in many livers during cold storage and is associated with poor posttransplant outcomes. The amount of D-dimer released after fibrinolytic treatment indicates a significant occult fibrin burden and suggests that fibrinolytic therapy during NESLiP may be a promising therapeutic intervention.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Elucidating mechanisms of genetic cross-disease associations at the PROCR vascular disease locus

Many individual genetic risk loci have been associated with multiple common human diseases. However, the molecular basis of this pleiotropy often remains unclear. We present an integrative approach to reveal the molecular mechanism underlying the PROCR locus, associated with lower coronary artery disease (CAD) risk but higher venous thromboembolism (VTE) risk. We identify PROCR-p.Ser219Gly as the likely causal variant at the locus and protein C as a causal factor. Using genetic analyses, human recall-by-genotype and in vitro experimentation, we demonstrate that PROCR-219Gly increases plasma levels of (activated) protein C through endothelial protein C receptor (EPCR) ectodomain shedding in endothelial cells, attenuating leukocyte-endothelial cell adhesion and vascular inflammation. We also associate PROCR-219Gly with an increased pro-thrombotic state via coagulation factor VII, a ligand of EPCR. Our study, which links PROCR-219Gly to CAD through anti-inflammatory mechanisms and to VTE through pro-thrombotic mechanisms, provides a framework to reveal the mechanisms underlying similar cross-phenotype associations.

Direct oral anticoagulants-Remove versus Taipan snake venom time for detection of a lupus anticoagulant in patients taking oral direct factor Xa inhibitors

BACKGROUND

The optimal method of detecting a lupus anticoagulant (LA) for patients taking direct factor Xa inhibitor (DFXaI) direct oral anticoagulants (DOACs) remains controversial. Methods include charcoal adsorption of the DOACs to allow testing with the activated partial thromboplastin time (APTT) and dilute Russell viper venom time (dRVVT), or use of the DFXaI-insensitive Taipan snake venom time (TSVT) and Ecarin time (ET) assays on neat plasma.

OBJECTIVES

The objective was to compare the utility of APTT and dRVVT analysis following DOAC Remove against TSVT/ET on untreated plasma for LA detection in spiked plasmas and routine clinical samples for patients on DFXaIs.

PATIENTS/METHODS

Various LA-negative and LA-positive samples were assayed by APTT, dRVVT, and TSVT/ET, and then separately spiked with rivaroxaban, apixaban, and edoxaban calibrators to a concentration of ~190 ng/ml and the assays repeated on spiked plasma before and after DOAC Remove treatment. Testing of 284 consecutive samples from DFXaI-anticoagulated patients by APTT/dRVVT and TSVT/ET before and after DOAC Remove treatment was undertaken.

RESULTS

In the spiking model, we found that both TSVT/ET and DOAC Remove strategies generally distinguished LA-negative and LA-positive samples, but some false-positive LA results occurred. In the investigation of 284 consecutive patient samples on DFXaIs, the percentage agreement for LA detection in neat samples tested by TSVT/ET versus APTT and dRVVT after DOAC Remove treatment was 90% (Cohen kappa 0.12).

CONCLUSION

Our data highlight uncertainty and disagreement for testing LA in patients on DFXaI. Further studies are required.

Current practice and registration patterns among United Kingdom Haemophilia Centre Doctors' Organisation centers for patients with unclassified bleeding disorders

BACKGROUND

Bleeding of unknown cause (BUC) and unclassified bleeding disorders (UBD) are increasingly recognized. There is no guidance on diagnosis and management.

OBJECTIVES

To examine UK haemophilia centre registration patterns and current practice for UBD patients.

METHODS

In a two-step process, the UK National Haemophilia Database (NHD) was reviewed for registration patterns of UBD patients and a survey of UK haemophilia centers was conducted (January/February 2021) to capture current practice for diagnosis and management of patients with UBD.

RESULTS/DISCUSSION

Overall, registrations with the NHD for UBD patients has sharply risen from 2012 to 2020 and in 2019 accounted for 2.65% of registered patients. For the survey, the response rate was 52/67 (78%). Practice was widely variable; 35/52 (67%) centers register UBD; among these 35 centers, terminology included UBD (28 centers), undiagnosed bleeding disorder (four centers), and BUC (three centers); 34/52 (65%) centers use a formal bleeding assessment tool. For management of dental extraction and high bleeding risk surgery in a fictional UBD patient we found that tranexamic acid was widely used; however, beyond this a variety of hemostatic products were advised including blood products, recombinant factor VIIa/prothrombin complex concentrate, and desmopressin. There was general consensus (≈90%) on avoiding regional anesthesia in pregnancy, but no agreement on the need for fetal precautions to avoid bleeding at delivery (50% would advise these). There was a disparity of opinion on chemical thromboprophylaxis, and management of patients without prior hemostatic challenges and offspring of these patients.

CONCLUSION

This study provides a snapshot of current practice and real-world data in this area. Future studies need to address the gaps in evidence.

60 The Effect of the 2020 COVID-19 Pandemic on Periprosthetic Joint Infection in Hip Fracture Surgery

Aim

To assess whether this change of practice had an effect on the infection rate in hip fracture surgery.

Method

An audit was conducted to assess the re-operation rate on hip fracture patients over the three months of the initial “lockdown” (23rd March to 23rd May 2020) and compared to the 2 months immediately before and the same period in 2019. Cases were identified from the Theatre ORACLE system (GE Healthcare). Anonymised patient data was collected from the Electronic Patient Record (EPR) and paper case notes.

Results

During the pandemic period, a total of 45 patients underwent surgery for hip fractures with a median age 84 years (range 28-95 years). These represent similar cohorts to the periods immediately before lockdown and the previous year. The infection rate increased from 0% in the 2019 period to 2.5% prior to lockdown and 11.1% after the lockdown measures were implemented. All infections were in patients who received hemiarthroplasty. The rate of total hip replacement went down from 19.1% in 2019 to 10.0% just before the pandemic and just 4.4% during the pandemic

Conclusions

There was a marked increase in the number of re-operations for infection in patients who received hemiarthroplasty for hip fractures during the lockdown period.

Investigation of platelet function in patients with chronic kidney disease stages IV-V

INTRODUCTION

Patients with renal failure are at increased risk of both bleeding and thrombosis. Further descriptions of laboratory investigations in these patients are required.

METHODS

Investigation of 24 patients with chronic kidney disease (CKD) stages IV-V with light transmission aggregometry, platelet secretion assays and platelet nucleotide analysis. Patients were in a nonbleeding state and not on antiplatelet medication. Results were compared with our local reference range used within the clinical haematology service.

RESULTS

Of the 24 patients, two had decreased responses to arachidonic acid, adenosine diphosphate, collagen, thrombin receptor activator peptide-6 and one had decreased responses to high dose ristocetin, and one had increased response to low dose ristocetin. 11 and 13 out of 24 had abnormal platelet secretion release to collagen and thrombin, respectively. Platelet nucleotide analysis in patients was normal with the exception of a reduction in ADP content in one patient and ATP/ADP ratio in one patient.

CONCLUSIONS

In our collection of patients with CKD investigated for platelet function in the nonbleeding state, they generally had normal light transmission aggregometry and nucleotide analysis but around 50% had decreased platelet secretion assays. These results could be important in determining the significance of platelet function tests in patients with bleeding symptoms and renal failure. Further characterization of platelet function tests in future will help characterize haemostasis in renal failure further.

536 Use of A Cost-Efficient Colonoscopy Simulation Model to Improve Endoscopy Skills During the COVID Pandemic

Introduction

The use of endoscopic simulators as a learning aid in surgical training has been well established. This has been emphasised during the challenging times of COVID-19. However, their utility for training is countered by the high cost of the equipment, with the most basic simulators costing upwards of £50,000.

Method

A simple polypectomy simulator model was created using a drain-pipe and surgical gloves. n = 9 junior doctors were timed in their ability to remove the 3 polyps from the simulator. The exercise was repeated over 6 sessions over the course of 3 weeks. Means were compared using ANOVA.

Results

There was a mean relative reduction of 75% in overall time taken to complete the task(p < 0.0001). This improvement was seen for both surgical trainees(p = 0.005) and FY1 novices(p < 0.0001) and junior doctors reported feeling more confident with basic Colonoscopic skills.

Conclusions

We have demonstrated an improvement in performance times across both surgical trainees and novices. In today’s era of COVID-19, when direct training opportunities may become more scarce, simple alternatives may become vital in ensuring progression of basic surgical skills such as endoscopy. This cheap polypectomy simulator can be easily re-created across surgical units and can be used as an adjunct to traditional endoscopic training

Complications and functional outcomes after ileo-anal pouch excision-a systematic review of 14 retrospective observational studies

PURPOSE

The ileo-anal pouch (IAP) has been the gold standard procedure for maintenance of bowel continuity after panproctocolectomy for ulcerative colitis, familial adenomatous polyposis or hereditary non-polyposis colorectal cancer. However, the IAP has an estimated failure rate of 13% at 10 years post-procedure (Tulchinsky et al., Ann Surg 238(2):229-34, 2003), which can result in pouch excision (P.E.). This systematic review aims to synthesise all the available studies reporting post-operative outcomes of P.E. and its impact on patient quality of life (QoL), when available, which have not previously been summarised.

METHODS

PubMed, Embase, Medline and the Cochrane library databases were searched with terms 'Pouch AND excision' OR 'Pouch AND removal' OR 'Pouch AND remove' OR 'IAP AND excision'. All studies reporting post-operative morbidity, mortality or functional outcomes in patients who had P.E. were included. Studies with < 5 patients, non-English studies and conference abstracts were excluded.

RESULTS

14 studies comprising 1601 patients were included. Overall complications varied from 18 to 63% with the most common being persistent perineal sinus (9-40%) or surgical site infection (wound-2 to 30%; intra-abdominal collection-3 to 24%). The mortality rate was between 0.58 and 1.4%. QoL is generally lower in P.E. patients compared to the normal population across various QoL measures and P.E. patients often had urinary and sexual dysfunction post-operatively.

CONCLUSIONS

There is a substantial incidence of complications after P.E.; however, there is no evidence describing QoL pre- and post-P.E. Further longitudinal research comparing QoL in patients undergoing P.E. and other treatment options such as indefinite diversion is required to definitively assess QoL post-procedure.

Evaluation of COVID-19 coagulopathy; laboratory characterization using thrombin generation and nonconventional haemostasis assays

INTRODUCTION

Patients with COVID-19 are known to have a coagulopathy with a thrombosis risk. It is unknown whether this is due to a generalized humoral prothrombotic state or endothelial factors such as inflammation and dysfunction. The aim was to further characterize thrombin generation using a novel analyser (ST Genesia, Diagnostica Stago, Asnières, France) and a panel of haematological analytes in patients with COVID-19.

METHODS

Platelet poor plasma of 34 patients with noncritical COVID-19 was compared with 75 patients with critical COVID-19 (as defined by WHO criteria) in a retrospective study by calibrated automated thrombography and ELISA. Patients were matched for baseline characteristics of age and gender.

RESULTS

Critical patients had significantly increased fibrinogen, CRP, interleukin-6 and D-dimer compared to noncritical patients. Thrombin generation, in critical patients, was right shifted without significant differences in peak, velocity index or endogenous thrombin potential. Tissue plasminogen activator (tPA), tissue factor pathway inhibitor (TFPI) and vascular endothelial growth factor (VEGF) were significantly increased in the critical versus noncritical patients. Critically ill patients were on haemodiafiltration (31%; heparin used in the circuit) or often received escalated prophylactic low-molecular weight heparin.

CONCLUSION

These results confirm increased fibrinogen and D-dimer in critical COVID-19-infected patients. Importantly, disease severity did not increase thrombin generation (including thrombin-antithrombin complexes and prothrombin fragment 1 + 2) when comparing both cohorts; counter-intuitively critical patients were hypocoaguable. tPA, TFPI and VEGF were increased in critical patients, which are hypothesized to reflect endothelial dysfunction and/or contribution of heparin (which may cause endothelial TFPI/tPA release).

Direct Oral Anticoagulant Concentrations in Obese and High Body Weight Patients: A Cohort Study

BACKGROUND

 Direct oral anticoagulants (DOACs) are prescribed for atrial fibrillation (AF) and venous thromboembolism (VTE) and both occur more frequently in obese patients. Outcomes from DOAC trials included few individuals ≥ 120 kg leading to uncertainty whether high body weight (BW) reduces DOAC concentrations.

OBJECTIVES

 This article investigates the relationship between factor Xa (FXa) inhibitor concentrations, BW, and renal function, and compares them in high BW patients with unselected populations.

METHODS

 Consecutive patients in two United Kingdom centers, weighing ≥ 120 kg receiving 5 mg twice daily apixaban or 20 mg once daily rivaroxaban for AF or VTE were prospectively included. Peak or trough concentrations were measured using specific chromogenic assays, expressed in mean or median (5th-95th percentiles). On-therapy range was the interval from the 5th percentile trough concentration to the 95th percentile peak concentration.

RESULTS

 One hundred patients were included; age range: 23 to 78 years, 31% were women, 58% had AF, creatinine clearance range: 67 to 474 mL/min. Median BW was 139 kg, and 84% had body mass index (BMI) ≥ 40 kg/m². DOAC peak and trough concentrations varied from 44 to 727 and 14 to 299 ng/mL, respectively. There was no linear relationship between FXa inhibitor concentrations at peak or trough and BW or BMI, and creatinine clearance. Apixaban troughs in AF and rivaroxaban peaks in VTE were lower than in unselected populations. However, only two trough concentrations were below the expected range, and 109/116 were within the on-therapy range.

CONCLUSION

 These data indicated that obese or high BW patients generally achieve therapeutic FXa inhibitor concentrations. However, further investigations assessing clinical outcomes are required.

Heparin resistance in COVID-19 patients in the intensive care unit

Patients with COVID-19 have a coagulopathy and high thrombotic risk. In a cohort of 69 intensive care unit (ICU) patients we investigated for evidence of heparin resistance in those that have received therapeutic anticoagulation. 15 of the patients have received therapeutic anticoagulation with either unfractionated heparin (UFH) or low molecular weight heparin (LMWH), of which full information was available on 14 patients. Heparin resistance to UFH was documented in 8/10 (80%) patients and sub-optimal peak anti-Xa following therapeutic LMWH in 5/5 (100%) patients where this was measured (some patients received both anticoagulants sequentially). Spiking plasma from 12 COVID-19 ICU patient samples demonstrated decreased in-vitro recovery of anti-Xa compared to normal pooled plasma. In conclusion, we have found evidence of heparin resistance in critically unwell COVID-19 patients. Further studies investigating this are required to determine the optimal thromboprophylaxis in COVID-19 and management of thrombotic episodes.

Evaluation of Point-of-Care ACT Coagulometers and Anti-Xa Activity During Cardiopulmonary Bypass

OBJECTIVE

The activated clotting time (ACT) is used worldwide to confirm safe heparin anticoagulation for cardiopulmonary bypass. For the present study, the performances of 2 commonly used ACT devices were compared with each other and with anti-Xa levels throughout the surgical procedure in order to understand whether they can be used interchangeably.

DESIGN

Prospective study.

SETTING

Tertiary care center.

PARTICIPANTS

The study comprised 33 elective adult cardiac surgical patients.

INTERVENTIONS

Blood samples were taken at standard times throughout the surgery (after induction, after heparin bolus, 4 samples at 30-minute intervals during cardiopulmonary bypass, after protamine), and ACTs and anti-Xa levels were analyzed. Data were compared using receiver operating characteristics and LOESS regression.

MEASUREMENTS AND MAIN RESULTS

The correlation between anti-Xa levels and the Hemochron ACT (Instrumentation Laboratory, Bedford, MA) was acceptable (r = 0.82, 95% confidence interval [CI] 0.757-0.868; p < 0.0001), as was the correlation between anti-Xa levels and the i-STAT (Abbott Point of Care, Abbott Park, IL) (r = 0.81, 95% CI 0.738-0.858; p < 0.0001). The correlation between the 2 ACT methods was poorer (r = 0.77, 95% CI 0.707-0.828; p < 0.0001) than their correlation to anti-Xa levels. When compared with anti-Xa levels, the sensitivity and specificity were mediocre for both devices, although the i-STAT performed better than the Hemochron ACT. The Hemochron ACT read higher values than the i-STAT ACT throughout the course of the surgery.

CONCLUSION

The correlation between the Hemochron ACT and i-STAT ACT is moderate, and they have different sensitivity and specificity when compared with anti-Xa levels. This suggests that ACT devices should not be used interchangeably, but cut-off values for safe anticoagulation during cardiopulmonary bypass should be determined for each type of device, particularly when switching supplier.

Balanced Steady-State Free Precession Techniques Improve Detection of Residual Germ Cell Tumor for Treatment Planning

BACKGROUND AND PURPOSE

Identification of a partial/complete chemotherapy response in pediatric patients with intracranial germ cell tumors is clinically important for radiation treatment and management. Partial/complete response is conventionally determined on postcontrast MR imaging sequences. The purpose of this study was to assess the diagnostic utility of a balanced steady-state free precession sequence as an adjunct to standard MR imaging sequences for the detection of residual tumor in pediatric patients on postchemoreduction pre-radiation planning MR imaging.

MATERIALS AND METHODS

This was a retrospective study of pediatric patients with intracranial germ cell tumors undergoing postchemotherapy, preradiotherapy MR imaging. Patients underwent 1.5T or 3T MR imaging with pre- and postcontrast T1WIs, T2WIs, and a balanced steady-state free precession sequence. Two neuroradiologists independently reviewed standard MR imaging sequences without the balanced steady-state free precession sequence, then with the balanced steady-state free precession sequence 1 week later. Assessment for partial/complete response was determined using Response Assessment in Neuro-Oncology criteria. A 5-point Likert scale scored the diagnostic confidence of the neuroradiologist rating each study without/with the balanced steady-state free precession sequence. Rates of residual disease concordance and diagnostic confidence levels without/with the balanced steady-state free precession sequence were calculated.

RESULTS

Thirty-nine patients were included with 31 males and 8 females (mean age, 14.15 ± 4.26 years). Thirty-one patients had single-site disease; 8 patients had multisynchronous disease (47 sites in total). Compared to review of the standard MR sequences alone, the addition of the balanced steady state free precession sequence resulted in higher rates of tumor partial response categorization and greater diagnostic confidence levels (P < .001, P < .001).

CONCLUSIONS

The balanced steady-state free precession sequence improves detection of residual chemotherapy-reduced intracranial germ cell tumors and increases diagnostic confidence of the neuroradiologist. The balanced steady-state free precession sequence may be an important adjunct to the standard MR imaging protocol for radiation planning.

A67 EVALUATING ACCESS TO IBD CARE ACROSS CANADA: PROCEEDINGS FROM THE 2017 IBD ACCESS SUBMMIT

Background

Inflammatory Bowel Disease (IBD) is a chronic, immune-mediated disease, with Canada demonstrating the highest incidence and prevalence rates in the world. Patients with IBD often require lifelong treatment and, therefore, lifelong interactions with the healthcare system. Access to care can have a direct impact on patient health-related outcomes. Although acknowledged as a problem, the complexity of accessing IBD specialty care in Canada has not been reviewed. This lack of understanding presents a barrier in evaluating and implementing changes in IBD specialty care.

Aims

To identify key barriers and facilitators for and to develop a national working strategy to address limitations in access to IBD specialty care by exploring the perceptions and experiences of key stakeholders (pediatric and adult gastroenterologists, IBD patients, researchers, and policy makers).

Methods

The IBD Summit was held in Toronto, Ontario in November 2017, sponsored by SPOR-CIHR catalyst funding and in partnership with Crohn’s & Colitis Canada. Perceptions and experiences of key stakeholders were gathered during two audio-recorded stakeholder dialogues held during the Summit. The audio recordings were transcribed and coded to compare and contrast between key stakeholders to determine potential differences in access to IBD care. Five final themes are highlighted in this report.

Results

A total of 21 key stakeholders attended, including pediatric and adult gastroenterologists, patients, researchers, and policy makers. Five key themes of importance relating to access to IBD care arose from The IBD Summit:(1) Integrated Models of Care, (2) IT Enhanced Care, (3) Health System Process, (4) Communication and Advocacy, and (5) Community Supports. The IBD Summit identified similar perceptions and experiences, highlighting common barriers and facilitators that transcend provincial borders. Shared perceptions included a need for common medical records and overall improved IT-enhanced care for managing IBD; improved centralized triage systems; increased comprehensive care support for patients and primary care physicians; and increased community supports for patients and providers.

Conclusions

Highlights from the IBD Summit present several clinically relevant and actionable suggestions for improved access to IBD speciality care across Canada. The suggestions provided by key stakeholders highlight the need for a system-level redesign in order to improve access to enhanced models of care. Improvements in access to IBD specialty care can only occur through partnerships between those working within the healthcare system and those within the community. Future research will involve pursuing deeper insight into the experience of patient and provider stakeholders as they navigate the healthcare system in order to access and provide care.

Funding Agencies

CIHRNova Scotia Health Authority Research Fund

Investigation of patients with unclassified bleeding disorder and abnormal thrombin generation for physiological coagulation inhibitors reveals multiple abnormalities and a subset of patients with increased tissue factor pathway inhibitor activity

INTRODUCTION

We have routinely used thrombin generation to investigate patients with unclassified bleeding disorder (UBD).

AIMS

To investigate haemostatic abnormalities in patients with UBD that had abnormal thrombin generation on at least one occasion.

METHODS

Investigation of 13 known UBD patients with thrombin generation and detailed haemostatic testing was undertaken including TFPI assays but also thrombomodulin and fibrinogen-γ.

RESULTS

12 females and 1 male were included. No patient had a platelet function disorder or coagulation factor deficiency that explained the bleeding phenotype, though 2 patients had factor deficiencies; a factor X of 0.41 IU/mL and a factor XI of 0.51 IU/mL. ThromboGenomics revealed variants for these factors but no other abnormalities. Patients were included who previously had either prolonged lag time or decreased endogenous thrombin potential (ETP) via high dose tissue factor (5 pmol/L) or low dose tissue factor (1.5 pmol/L) with corn trypsin inhibitor (CTI). Tissue factor pathway inhibitor (TFPI) activity was significantly increased (P < .001; increased in 8 patients) compared with controls and abnormalities in soluble thrombomodulin (2 patients), fibrinogen-γ (1 patient) and tPA (4 patients for each) were seen. Total and free TFPI levels were not increased. Mixing studies of patient plasma with 50:50 normal plasma for thrombin generation via low dose tissue factor failed to correct the ETP consistent with ongoing inhibition. Addition of an anti-TFPI antibody partially corrected thrombin generation to normal levels. TFPI sequencing was unremarkable.

CONCLUSION

TFPI activity may be increased in a subset of UBD patients. Further research studies are warranted in UBD patients for coagulation inhibitor abnormalities.

Liquid Chromatographic Determination of Ochratoxin A in Barley, Wheat Bran, and Rye by the AOAC/IUPAC/NMKL Method: NMKL Collaborative Study1

In an inter laboratory study of the AOAC/lnternational Union of Pure and Applied Chemistry (IUPAC)/ Nordic Committee on Food Analysis (NMKL) liquid chromatographic method for ochratoxin A (OTA), 3 spiked samples each of wheat bran and rye and 3 naturally contaminated barley samples with expected OTA contents between 2 and 9 μg/kg were analyzed by 12 European laboratories. Mean recoveries ranged from 64 to 72%. Within-laboratory standard deviations were 21,17, and 12% for wheat bran, rye, and barley, respectively. Corresponding between-laboratory standard deviations were 23-28,20-28, and 18-31%. Horwitz ratio values ranged from 0.50 to 0.77. The method was accepted as an official NMKL method for determining OTA at ≥2 μg/kg in cereals and cereal products.

Determination of Patulin in Apple Juice by Liquid Chromatography: Collaborative Study

An AOAC International-International Union of Pure and Applied Chemistry-International Fruit Juice Union (AOAC-IUPAC-IFJU) collaborative study was conducted to evaluate a liquid chromatographic (LC) procedure for determination of patulin in apple juice. Patulin is a mold metabolite found naturally in rotting apples. Patulin is extracted with ethyl acetate, treated with sodium carbonate solution, and determined by reversed-phase LC with UV detection at 254 or 276 nm. Water, water-tetrahydrofuran, or water-acetonitrile was used as mobile phase. Levels determined in spiked test samples were 20, 50,100, and 200 μg/L. A test sample naturally contaminated at 31 μg/L was also included. Twenty-two collaborators in 10 countries analyzed 12 test samples of apple juice. Recoveries averaged 96%, with a range of 91-108%. Repeatability relative standard deviations (RSDr) ranged from 10.9 to 53.8%. The reproducibility relative standard deviation (RSDR) ranged from 15.1 to 68.8%. The LC method for determination of patulin in apple juice has been adopted first action by AOAC INTERNATIONAL.

Determination of Fumonisins B1 and B2 in Corn by LC/MS with Immunoaffinity Column Cleanup: Interlaboratory Study

An interlaboratory validation study was conducted to establish the method performance characteristics of an immunoaffinity column (IAC) cleanup procedure followed by LC/MS for the determination of fumonisins B1 (FB1) and B2 (FB2) and combined FB1 + FB2 in corn. The test portion is extracted with acetonitrilemethanolwater (25 + 25 + 50). The extract is filtered, diluted with phosphate-buffered saline solution, and applied to an IAC. FB1 and FB2 are removed with methanol, followed by water, then directly determined by RPLC with MS detection using selected-ion monitoring of two characteristic ions in each case. Naturally contaminated corn samples were milled to a fine powder and mixed to produce three samples with target levels of combined FB1 + FB2 ranging from 350 to 4000 g/kg. Of 15 initially participating laboratories, two failed to report results and another did not follow the prescribed method. Thus, valid results were obtained from 12 participants located in 11 countries. Statistical analysis of the results produced RSDr values of 4.611.9, 1.912.6, and 1.411.5 for FB1, FB2, and combined FB1 + FB2, respectively; the corresponding RSDR values were 19.823.8, 18.225.5, and 18.823.2. The three concentration levels of combined FB1 + FB2 were 534, 1194, and 1954 g/kg. HorRat values for r and R were all &lt;2.0, indicating that the method is suitable as a regulatory method for the enforcement of European Union limits for fumonisins in corn.

Determination of Fumonisins B1 and B2 in Corn-Based Foods for Infants and Young Children by LC with Immunoaffinity Column Cleanup: Interlaboratory Validation Study

A liquid chromatographic method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn-based foods for infants and young children was subjected to an interlaboratory validation study involving 11 laboratories. Five blind duplicate sample pairs of each matrix were analyzed to establish the accuracy, repeatability, and reproducibility of the method. Mass fractions in the baby food samples ranged from 89.1 to 384.4 μg/kg FB1 and from 22.5 to 73.6 μg/kg FB2. The method involved a warm extraction with citrate phosphate buffer–methanol–acetonitrile (50 + 25 + 25, v/v/v), a cleanup through an immunoaffinity column, and an end-determination of fumonisins by LC after automated precolumn derivatization with-o-phthaldialdehyde reagent. RSDs for within- laboratory repeatability (RSDr) ranged from 6.8 to 23.5% for FB1 and 7.6 to 22.9% for FB2. RSDs for between-laboratory reproducibility (RSDR) ranged from 15.4 to 26.2% for FB1 and 21.6 to 36.3% for FB2. Mean FB1 recoveries from baby foods spiked at 100.0 and 250.0 μg/kg were 89 and 96%, respectively; for FB2 spiked foods at 25.0 and 62.5 μg/kg recoveries were 90 and 85%, respectively. HorRat values ranged from 0.8 to 1.2 for FB1, whereas for FB2 they ranged from 0.9 to 1.4 when calculated according to Horwitz, and from 1.0 to 1.7 when calculated according to Thompson, indicating an acceptable among- laboratory precision for all matrixes (HorRat values &lt;2).

Determination of Ochratoxin A in Green Coffee by Immunoaffinity Column Cleanup and Liquid Chomatography: Collaborative Study

A collaborative study was conducted to evaluate a method using immunoaffinity column cleanup with liquid chromatography (LC) for the determination of ochratoxin A (OTA) in green coffee at levels that could be included in possible future regulations of the European Union. The test portion was extracted with methanol–3% aqueous sodium hydrogen carbonate solution (50 + 50, v/v). The extract was filtered, and the filtrate was diluted with phosphate-buffered saline and applied to an immunoaffinity column containing antibodies specific for OTA. After washing, the toxin was eluted from the column with methanol and quantified by LC with fluorescence detection. Pairs of 4 homogeneous noncontaminated and naturally contaminated materials (mean levels of &lt;0.12, 2.44, 5.15, and 13.46 ng/g) and blank samples (&lt;0.12 ng/g) for spiking were sent to 20 participant laboratories from 8 countries. The materials were analyzed according to the method description and all difficulties encountered in the analysis were reported. Statistical analysis was carried out according to the Harmonized Protocol of the International Union of Pure and Applied Chemistry. The relative standard deviation for repeatability (RSDr) ranged from 7.42 to 20.94%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.34 to 29.17%. The method showed acceptable within-laboratory and between-laboratories precision for green coffee materials, as evidenced by HorRat values of ≤0.85, at the studied range, for spiked and naturally contaminated materials. The mean recovery was 92.8% for green coffee material spiked with OTA at a level of 4.82 ng/g.

Immunoaffinity Column Cleanup with Liquid Chromatography Using Post-Column Bromination for Determination of Aflatoxin B1 in Cattle Feed: Collaborative Study

A collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for determination of aflatoxin B1 in cattle feed at a possible future European regulatory limit (1 ng/g). The test portion was extracted with acetone–water (85 + 15), filtered, diluted with water, and applied to an immunoaffinity column. The column was washed with water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. Aflatoxin B1 was separated and determined by reversed-phase liquid chromatography (RP–LC) and detected by fluorescence after post column derivatization (PCD) involving bromination. PCD was achieved with either pyridinium hydrobromide perbromide (PBPB), used by 14 laboratories, or an electrochemical cell and addition of bromide to the mobile phase, used by 7 laboratories. Both derivatization techniques were not significantly different when compared by the t-test; the method was statistically evaluated for all laboratories together (bromination and PBPB). The cattle feed samples, both spiked and naturally contaminatedwithaflatoxinB1, were sent to 21 laboratories in 14 different countries (United States, Japan, and Europe). Test portions were spiked at levels of 1.2 and 3.6 ng/g for aflatoxin B1. Recoveries ranged from 74 to 157%. Based on results for spiked samples (blind pairs at 2 levels) as well as naturally con-taminated samples (blind pairs at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 5.9 to 8.7%. The relative standard deviation for reproducibility (RSDR) ranged from 17.5 to 19.6%. The method showed acceptable within-and between-laboratory precision for this matrix, as evidenced by HORRAT values, at the target levels of determination for aflatoxin B1. No major differences in RSD were observed, showing that the composition of the feeds was not a factor for the samples tested and that the method was applicable for all materials used.

Time to Diagnosis and Treatment with Palliative Radiotherapy among Inuit Patients with Cancer from the Arctic Territory of Nunavut, Canada

AIMS

The cancer burden among Circumpolar Inuit is high. Palliative radiotherapy is a mainstay treatment for controlling symptoms of advanced cancers, but Inuit are required to travel far distances to access this service. Access to palliative radiotherapy and time away from home communities have not been explored among this population. We sought to describe the time intervals from symptom onset to the start of palliative radiotherapy among Canadian Inuit patients treated at The Ottawa Hospital (TOH).

MATERIALS AND METHODS

A retrospective review of Inuit patients from Nunavut treated with radiotherapy between 2005 and 2014 at TOH.

RESULTS

Of a total of 152 radiotherapy patients, 88 (58%) were treated palliatively. Of these, 61 (70%) had stage IV disease at diagnosis and 63 (72%) had lung cancer. The median time from referral for specialist care to the patient's first flight to Ottawa was 4 days (range 0-97). The median length of treatment was 7 days (range 0-27), but patients spent a median of 64.5 days (range 14-633) in Ottawa. The median survival from the date of pathological diagnosis was 5.2 months.

CONCLUSIONS

Most Inuit radiotherapy patients at TOH were treated palliatively. Patients were brought from Nunavut relatively quickly for specialist care, which is encouraging. However, patients spent over 2 months away from home, in the context of a median survival of less than 6 months. Opportunities for improvement include both provider and system-level changes, which may be applicable to other Circumpolar Inuit regions across Europe and North America.

Improving End-of-Life Care and Advance Care Planning for Frail Older Adults in Canad

We present five Key Concepts that describe priorities for improving end-of-life care for frail older adults in Canada, and recommendations based on each Key Concept. Key Concept #1: Our end-of-life care system is focused on cancer, not frailty. Key Concept #2: We need better strategies to systematically identify frail older adults who would benefit from a palliative approach. Key Concept #3: The majority of palliative and end-of-life care will be, and should be, provided by clinicians who are not palliative care specialists. Key Concept #4: Organizational change and innovative funding models could deliver far better end-of-life care to frail individuals for less than we are currently spending. Key Concept #5: Improving the quality and quantity of advance care planning for frail older adults could reduce unwanted intensive care and costs at the end of life, and improve the experience for individuals and family members alike.