Evaluating compliance of extended venous thromboembolism prophylaxis following abdominopelvic surgery for cancer: A multidisciplinary quality improvement project.

BACKGROUND AND OBJECTIVES: Despite quality evidence supporting postoperative extended venous thromboembolism prophylaxis (eVTEp) following abdominopelvic cancer surgery, baseline use of eVTEp at our institution was 3%. Our project aim was to improve the proportion of patients prescribed eVTEp following surgery for gynecologic, hepatobiliary, and colorectal cancers by a 30% absolute increase. METHODS: We performed an interrupted time series study using quality improvement methodology. Postoperative order sets, pre-printed prescriptions, process checklists, and multimodal education were introduced. Process and outcome data were collected and analyzed on statistical process control charts. RESULTS: We included 324 patients with gynecologic and hepatobiliary cancers. Despite efforts to include them, the colorectal team did not participate. The monthly mean order set-use was 58% (SD = 14%), by specialty: gynecology 79%, hepatobiliary 47%. The proportion of patients prescribed eVTEp increased from 3% to 70% (SD = 14%). The target goal was surpassed and sustained by both cohorts. Patient compliance was 73% (n = 117/160, SD = 16%). Of those who stopped eVTEp early, 45% (n = 14/31) objected because of the injectable nature. Bleeding events were infrequent (0.6%, n = 2/324). CONCLUSIONS: Three process changes and multimodal education resulted in a significant increase in eVTEp use. Failure to identify improvement champions limited project expansion to colorectal patients. Patient compliance was largely limited by the injectable nature of the medication.

Direct oral anticoagulants for treatment of HIT: update of Hamilton experience and literature review.

Direct oral anticoagulants (DOACs) are attractive options for treatment of heparin-induced thrombocytopenia (HIT). We report our continuing experience in Hamilton, ON, Canada, since January 1, 2015 (when we completed our prospective study of rivaroxaban for HIT), using rivaroxaban for serologically confirmed HIT (4Ts score ≥4 points; positive platelet factor 4 [PF4]/heparin immunoassay, positive serotonin-release assay). We also performed a literature review of HIT treatment using DOACs (rivaroxaban, apixaban, dabigatran, edoxaban). We focused on patients who received DOAC therapy for acute HIT as either primary therapy (group A) or secondary therapy (group B; initial treatment using a non-DOAC/non-heparin anticoagulant with transition to a DOAC during HIT-associated thrombocytopenia). Our primary end point was occurrence of objectively documented thrombosis during DOAC therapy for acute HIT. We found that recovery without new, progressive, or recurrent thrombosis occurred in all 10 Hamilton patients with acute HIT treated with rivaroxaban. Data from the literature review plus these new data identified a thrombosis rate of 1 of 46 patients (2.2%; 95% CI, 0.4%-11.3%) in patients treated with rivaroxaban during acute HIT (group A, n = 25; group B, n = 21); major hemorrhage was seen in 0 of 46 patients. Similar outcomes in smaller numbers of patients were observed with apixaban (n = 12) and dabigatran (n = 11). DOACs offer simplified management of selected patients, as illustrated by a case of persisting (autoimmune) HIT (>2-month platelet recovery with inversely parallel waning of serum-induced heparin-independent serotonin release) with successful outpatient rivaroxaban management of HIT-associated thrombosis. Evidence supporting efficacy and safety of DOACs for acute HIT is increasing, with the most experience reported for rivaroxaban.

Venous Thromboembolic Events Following Major Pelvic and Abdominal Surgeries for Cancer: A Prospective Cohort Study.

OBJECTIVE: The aim of this study was to evaluate the incidence and risk factors for post-hospital discharge venous thromboembolism (VTE) following abdominal cancer surgery without post-discharge prophylaxis. METHODS: This was a single-center, prospective cohort study. Patients were evaluated at 1, 3, and 6 months from surgery for the presence of proximal deep vein thrombosis (DVT; screening ultrasound at 1 month and questionnaire at each visit). Cumulative VTE incidence with 95% confidence interval (CI) was estimated using Kaplan-Meier methods, and multivariable analysis was performed using a Cox proportional hazards model. RESULTS: Of 284 patients enrolled, 79 (28%) underwent colorectal laparotomy, 97 (34%) underwent hepatobiliary laparotomy, 100 (35%) underwent gynecological laparotomy, and 8 (3%) underwent exploratory laparotomy without resection. All patients received pre- and postoperative inpatient prophylaxis. The cumulative incidence of VTE at 1 month was 0.35% (95% CI 0.05-2.48), 2.5% at 3 months (95% CI 1.19-5.15), and 7.2% at 6 months (95% CI 4.72-10.97). Screening ultrasound performed 4 weeks after surgery in 50% of patients was negative for thrombosis in all cases. Event distribution was similar according to the type of surgery (open/laparoscopic) and type of cancer. Seventeen (6.6%) patients died (95% CI 3.5-9.4) (two had a VTE-related death). Postoperative chemotherapy and Caprini score were significantly associated with VTE [hazard ratios 3.77 (95% CI 1.56-9.12) and 1.17 (95% CI 1.02-1.34), respectively]. CONCLUSION: The incidence of post-hospital discharge proximal DVT and/or symptomatic VTE following abdominal and pelvic cancer surgery appears to be low. The cumulative number of events increased at 6 months, but this was likely due to additional risk factors that were not related to surgery. Postoperative chemotherapy increases the risk of VTE.

Combination of 4Ts score and PF4/H-PaGIA for diagnosis and management of heparin-induced thrombocytopenia: prospective cohort study.

Rapid exclusion of heparin-induced thrombocytopenia (HIT) is needed to determine which patients can continue to receive heparin. In this prospective management study, 526 participants had a 4Ts score, rapid particle gel immunoassay (platelet factor 4/heparin [PF4/H]-PaGIA), and serotonin-release assay (SRA) performed. While awaiting SRA results, participants with a low 4Ts score (irrespective of PF4/H-PaGIA result) or intermediate 4Ts score plus a negative PF4/H-PaGIA result received prophylactic doses of danaparoid or fondaparinux; all others received therapeutic doses of nonheparin anticoagulants. The primary outcome was the frequency of management failures defined as HIT-positive participants with a low 4Ts score (irrespective of PF4/H-PaGIA result) or intermediate 4Ts score plus negative PF4/H-PaGIA result. Six participants (1.1%; 95% confidence interval [CI], 0.2-2.1%) were management failures. A negative PF4/H-PaGIA result reduced the pretest probability of HIT from 1.9% to 0% (95% CI, 0-1.3%), 6.7% to 0% (95% CI, 0-2.7%), and 36.6% to 0% (95% CI, 0-14.3%) in the low, intermediate, and high score groups, respectively. A positive PF4/H-PaGIA result increased the probability of HIT in the low score group to 15.4% (95% CI, 5.9-30.5). Thus, a low or intermediate 4Ts score plus negative PaGIA result excluded HIT, whereas any other combination of results justified the use of alternative anticoagulants until HIT could be excluded. This trial was registered at www.clinicaltrials.gov as #NCT00489437.

Design of the rivaroxaban for heparin-induced thrombocytopenia study.

Rivaroxaban is an ideal potential candidate for treatment of heparin-induced thrombocytopenia (HIT) because it is administered orally by fixed dosing, requires no laboratory monitoring and is effective in the treatment of venous and arterial thromboembolism in other settings. The Rivaroxaban for HIT study is a prospective, multicentre, single-arm, cohort study evaluating the incidence of new symptomatic venous and arterial thromboembolism in patients with suspected or confirmed HIT who are treated with rivaroxaban. Methodological challenges faced in the design of this study include heterogeneity of the patient population, differences in the baseline risk of thrombosis and bleeding dependent on whether HIT is confirmed or just suspected, and heterogeneity in laboratory confirmation of HIT. The rationale for how these challenges were addressed and the final design of the Rivaroxaban for HIT study is reviewed.

Selective D-dimer testing for diagnosis of a first suspected episode of deep venous thrombosis: a randomized trial.

BACKGROUND: D-Dimer testing is sensitive but not specific for diagnosing deep venous thrombosis (DVT). Changing the use of testing and the threshold level for a positive test result on the basis of risk for DVT might improve the tradeoff between sensitivity and specificity and reduce the need for testing. OBJECTIVE: To determine whether using a selective D-dimer testing strategy based on clinical pretest probability (C-PTP) for DVT is safe and reduces diagnostic testing compared with using a single D-dimer threshold for all patients. DESIGN: Randomized, multicenter, controlled trial. Patients were allocated using a central automated system. Ultrasonographers and study adjudicators but not other study personnel were blinded to trial allocation. (ClinicalTrials.gov: NCT00157677) SETTING: 5 Canadian hospitals. PATIENTS: Consecutive symptomatic patients with a first episode of suspected DVT. INTERVENTION: Selective testing (n = 860), defined as D-dimer testing for outpatients with low or moderate C-PTP (DVT excluded at D-dimer levels <1.0 µg/mL [low C-PTP] or <0.5 µg/mL [moderate C-PTP]) and venous ultrasonography without D-dimer testing for outpatients with high C-PTP and inpatients, or uniform testing (n = 863), defined as D-dimer testing for all participants (DVT excluded at D-dimer levels <0.5 µg/mL). MEASUREMENTS: The proportion of patients not diagnosed with DVT during initial testing who had symptomatic venous thromboembolism during 3-month follow-up and the proportion of patients undergoing D-dimer testing and ultrasonography. RESULTS: The incidence of symptomatic venous thromboembolism at 3 months was 0.5% in both study groups (difference, 0.0 percentage point [95% CI, -0.8 to 0.8 percentage points]). Selective testing reduced the proportion of patients who required D-dimer testing by 21.8 percentage points (CI, 19.1 to 24.8 percentage points). It reduced the proportion who required ultrasonography by 7.6 percentage points (CI, 2.9 to 12.2 percentage points) overall and by 21.0 percentage points (CI, 14.2 to 27.6 percentage points) in outpatients with low C-PTP. LIMITATION: Results may not be generalizable to all D-dimer assays or patients with previous DVT, study personnel were not blinded, and the trial was stopped prematurely. CONCLUSION: A selective D-dimer testing strategy seems as safe as and more efficient than having everyone undergo D-dimer testing when diagnosing a first episode of suspected DVT. PRIMARY FUNDING SOURCE: Heart and Stroke Foundation of Ontario.

Joint 2022 European Society of Thoracic Surgeons and The American Association for Thoracic Surgery guidelines for the prevention of cancer-associated venous thromboembolism in thoracic surgery.

BACKGROUND: Venous thromboembolism (VTE), which includes deep vein thrombosis and pulmonary embolism, is a potentially fatal but preventable postoperative complication. Thoracic oncology patients undergoing surgical resection, often after multimodality induction therapy, represent among the highest risk groups for postoperative VTE. Currently there are no VTE prophylaxis guidelines specific to these thoracic surgery patients. Evidenced-based recommendations will help clinicians manage and mitigate risk of VTE in the postoperative period and inform best practice. OBJECTIVE: These joint evidence-based guidelines from The American Association for Thoracic Surgery and the European Society of Thoracic Surgeons aim to inform clinicians and patients in decisions about prophylaxis to prevent VTE in patients undergoing surgical resection for lung or esophageal cancer. METHODS: The American Association for Thoracic Surgery and the European Society of Thoracic Surgeons formed a multidisciplinary guideline panel that included broad membership to minimize potential bias when formulating recommendations. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used, including GRADE Evidence-to-Decision frameworks, which were subject to public comment. RESULTS: The panel agreed on 24 recommendations focused on pharmacological and mechanical methods for prophylaxis in patients undergoing lobectomy and segmentectomy, pneumonectomy, and esophagectomy, as well as extended resections for lung cancer. CONCLUSIONS: The certainty of the supporting evidence for the majority of recommendations was judged as low or very low, largely due to a lack of direct evidence for thoracic surgery. The panel made conditional recommendations for use of parenteral anticoagulation for VTE prevention, in combination with mechanical methods, over no prophylaxis for cancer patients undergoing anatomic lung resection or esophagectomy. Other key recommendations include: conditional recommendations for using parenteral anticoagulants over direct oral anticoagulants, with use of direct oral anticoagulants suggested only in the context of clinical trials; conditional recommendation for using extended prophylaxis for 28 to 35 days over in-hospital prophylaxis only for patients at moderate or high risk of thrombosis; and conditional recommendations for VTE screening in patients undergoing pneumonectomy and esophagectomy. Future research priorities include the role of preoperative thromboprophylaxis and the role of risk stratification to guide use of extended prophylaxis.

Protocol for a living evidence synthesis on variants of concern and COVID-19 vaccine effectiveness.

BACKGROUND: It is evident that COVID-19 will remain a public health concern in the coming years, largely driven by variants of concern (VOC). It is critical to continuously monitor vaccine effectiveness as new variants emerge and new vaccines and/or boosters are developed. Systematic surveillance of the scientific evidence base is necessary to inform public health action and identify key uncertainties. Evidence syntheses may also be used to populate models to fill in research gaps and help to prepare for future public health crises. This protocol outlines the rationale and methods for a living evidence synthesis of the effectiveness of COVID-19 vaccines in reducing the morbidity and mortality associated with, and transmission of, VOC of SARS-CoV-2. METHODS: Living evidence syntheses of vaccine effectiveness will be carried out over one year for (1) a range of potential outcomes in the index individual associated with VOC (pathogenesis); and (2) transmission of VOC. The literature search will be conducted up to May 2023. Observational and database-linkage primary studies will be included, as well as RCTs. Information sources include electronic databases (MEDLINE; Embase; Cochrane, L*OVE; the CNKI and Wangfang platforms), pre-print servers (medRxiv, BiorXiv), and online repositories of grey literature. Title and abstract and full-text screening will be performed by two reviewers using a liberal accelerated method. Data extraction and risk of bias assessment will be completed by one reviewer with verification of the assessment by a second reviewer. Results from included studies will be pooled via random effects meta-analysis when appropriate, or otherwise summarized narratively. DISCUSSION: Evidence generated from our living evidence synthesis will be used to inform policy making, modelling, and prioritization of future research on the effectiveness of COVID-19 vaccines against VOC.

Joint 2022 European Society of Thoracic Surgeons and The American Association for Thoracic Surgery guidelines for the prevention of cancer-associated venous thromboembolism in thoracic surgery.

BACKGROUND: Venous thromboembolism (VTE), which includes deep vein thrombosis and pulmonary embolism, is a potentially fatal but preventable postoperative complication. Thoracic oncology patients undergoing surgical resection, often after multimodality induction therapy, represent among the highest risk groups for postoperative VTE. Currently there are no VTE prophylaxis guidelines specific to these thoracic surgery patients. Evidenced-based recommendations will help clinicians manage and mitigate risk of VTE in the postoperative period and inform best practice. OBJECTIVE: These joint evidence-based guidelines from The American Association for Thoracic Surgery and the European Society of Thoracic Surgeons aim to inform clinicians and patients in decisions about prophylaxis to prevent VTE in patients undergoing surgical resection for lung or esophageal cancer. METHODS: The American Association for Thoracic Surgery and the European Society of Thoracic Surgeons formed a multidisciplinary guideline panel that included broad membership to minimize potential bias when formulating recommendations. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used, including GRADE Evidence-to-Decision frameworks, which were subject to public comment. RESULTS: The panel agreed on 24 recommendations focused on pharmacological and mechanical methods for prophylaxis in patients undergoing lobectomy and segmentectomy, pneumonectomy, and esophagectomy, as well as extended resections for lung cancer. CONCLUSIONS: The certainty of the supporting evidence for the majority of recommendations was judged as low or very low, largely due to a lack of direct evidence for thoracic surgery. The panel made conditional recommendations for use of parenteral anticoagulation for VTE prevention, in combination with mechanical methods, over no prophylaxis for cancer patients undergoing anatomic lung resection or esophagectomy. Other key recommendations include: conditional recommendations for using parenteral anticoagulants over direct oral anticoagulants, with use of direct oral anticoagulants suggested only in the context of clinical trials; conditional recommendation for using extended prophylaxis for 28 to 35 days over in-hospital prophylaxis only for patients at moderate or high risk of thrombosis; and conditional recommendations for VTE screening in patients undergoing pneumonectomy and esophagectomy. Future research priorities include the role of preoperative thromboprophylaxis and the role of risk stratification to guide use of extended prophylaxis. (J Thorac Cardiovasc Surg 2022;▪:1-31).

Heparin-induced thrombocytopenia: real-world issues.

Heparin-induced thrombocytopenia (HIT) is a prothrombotic drug reaction caused by platelet-activating antibodies. HIT sera often activate platelets without needing heparin-such heparin-"independent" platelet activation can be associated with HIT beginning or worsening despite stopping heparin ("delayed-onset HIT"). We address important issues in HIT diagnosis and therapy, using a recent cohort of HIT patients to illustrate influences of heparin type; triggers for HIT investigation; serological features of heparin-independent platelet activation; and treatment. In our cohort of recent HIT cases ( N = 13), low-molecular-weight heparin (dalteparin) was a common causative agent ( N = 8, 62%); most patients were diagnosed after HIT-thrombosis had occurred; and danaparoid was the most frequently selected treatment. Heparin-independent platelet activation was common (7/13 [54%]) and predicted slower platelet count recovery (>1 week) among evaluable patients (5/5 vs 1/6; P = 0.015). In our experience with argatroban-treated patients, HIT-associated consumptive coagulopathy confounds anticoagulant monitoring. Our observations provide guidance on practical aspects of HIT diagnosis and management.

Challenging anticoagulation cases: A case of acute pulmonary embolism in a patient with chronic thrombocytopenia.

We present a case of acute pulmonary embolism in a patient with myelofibrosis and thrombocytopenia. The patient had a history of portal vein thrombosis and had taken warfarin for the past six years. At the time of his pulmonary embolism diagnosis, his INR was 1.5 and platelet count 58 × 109/L. This article discusses how to balance the risk of thrombosis against the risk of bleeding, and reviews the options for pulmonary embolism treatment including transition to low-molecular-weight heparin, direct oral anticoagulants and/or inferior vena cava filters.

Posthospital discharge venous thromboembolism prophylaxis among colorectal and hepatobiliary surgeons: A practice survey.

BACKGROUND: Recent practice guidelines recommend venous thromboembolism prophylaxis for 28 days after cancer surgery. We sought to characterize and compare awareness, agreement, adoption, and adherence to these guidelines among surgeons. METHODS: We electronically surveyed Canadian hepatobiliary surgeons registered with the Canadian Hepatopancreatobiliary Association, general and colorectal surgeons registered with the College of Physicians and Surgeons of Ontario and the Canadian Society of Colorectal Surgeons who provide colorectal cancer care with a pilot-tested questionnaire. Attitudes to relevant guideline recommendations and perceived barriers to postdischarge venous thromboembolism prophylaxis were assessed on a 5-point Likert scale. RESULTS: There were 128 responses (response rate 60%, 128 of 213), including 60 general/colorectal and 68 hepatobiliary surgeons. Most surgeons were aware (122 of 128, 95%), agreed (101 of 122, 83%), adopted (78 of 101, 77%), and adhered (74 of 78, 95%) with guidelines. Preexisting venous thromboembolism-prophylaxis hospital programs, hepatobiliary surgeons, and geographical region were associated with increased likelihood of adherence. Among respondents that did not agree, insufficient evidence (median Likert: 4, interquartile range 3-5) and low incidence of venous thromboembolism (median Likert: 4, interquartile range 3-4) were cited as the strongest barriers. Surgeons who agreed but did not adopt these programs reported that the most significant barriers were "drug cost" (median Likert: 4, interquartile range 3-4) and "subcutaneous injections" (median Likert: 4, interquartile range 3-4). Surgeons that adhered additionally reported "logistical challenges of prescribing" as the greatest implementation barrier. CONCLUSION: Surgeons who remain apprehensive about postdischarge venous thromboembolism prophylaxis cite poor evidence and cost of the medication as the major barriers. Adherence was higher among hepatobiliary surgeons and at hospitals with existing venous thromboembolism-prophylaxis programs.

A Deep Learning Approach to Refine the Identification of High-Quality Clinical Research Articles From the Biomedical Literature: Protocol for Algorithm Development and Validation.

BACKGROUND: A barrier to practicing evidence-based medicine is the rapidly increasing body of biomedical literature. Use of method terms to limit the search can help reduce the burden of screening articles for clinical relevance; however, such terms are limited by their partial dependence on indexing terms and usually produce low precision, especially when high sensitivity is required. Machine learning has been applied to the identification of high-quality literature with the potential to achieve high precision without sacrificing sensitivity. The use of artificial intelligence has shown promise to improve the efficiency of identifying sound evidence. OBJECTIVE: The primary objective of this research is to derive and validate deep learning machine models using iterations of Bidirectional Encoder Representations from Transformers (BERT) to retrieve high-quality, high-relevance evidence for clinical consideration from the biomedical literature. METHODS: Using the HuggingFace Transformers library, we will experiment with variations of BERT models, including BERT, BioBERT, BlueBERT, and PubMedBERT, to determine which have the best performance in article identification based on quality criteria. Our experiments will utilize a large data set of over 150,000 PubMed citations from 2012 to 2020 that have been manually labeled based on their methodological rigor for clinical use. We will evaluate and report on the performance of the classifiers in categorizing articles based on their likelihood of meeting quality criteria. We will report fine-tuning hyperparameters for each model, as well as their performance metrics, including recall (sensitivity), specificity, precision, accuracy, F-score, the number of articles that need to be read before finding one that is positive (meets criteria), and classification probability scores. RESULTS: Initial model development is underway, with further development planned for early 2022. Performance testing is expected to star in February 2022. Results will be published in 2022. CONCLUSIONS: The experiments will aim to improve the precision of retrieving high-quality articles by applying a machine learning classifier to PubMed searching. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/29398.

Double Blind Pilot Randomized Trial Comparing Extended Anticoagulation to Placebo Following Major Lung Resection for Cancer.

Venous thromboembolism (VTE), which comprises pulmonary embolus (PE) and deep vein thrombosis (DVT), is a significant cause of postoperative morbidity and mortality. This pilot randomized control trial (RCT) evaluated the feasibility of a full-scale RCT investigating extended thromboprophylaxis in patients undergoing oncological lung resections. Patients undergoing oncological lung resections in 2 tertiary centers received in-hospital, thromboprophylaxis and were randomized to receive post-discharge low-molecular-weight heparin (LMWH) or placebo injections once-daily for 30 days. At 30 days postoperatively, all patients underwent chest computed tomography with PE protocol and bilateral leg venous ultrasound. Primary outcomes included feasibility and safety; VTE incidence and 90-day survival were secondary outcomes. Between December 2015 and June 2018, 619 patients were screened, of whom 62.7% (165/263) of eligible patients consented to participate, and 133 (81%) were randomized. One-hundred and 3 patients, (77.4%), completed the 90-day study follow-up. Reasons for non-participation pre-randomization included patient discomfort and LMWH/placebo administration challenges. Post-randomization withdrawals were due to patient preference, surgeon preference and minor adverse events. Six asymptomatic VTE events (5 PE and 1 DVT) were detected within 30 days (3 in each group), for an overall incidence of 7%. There were 3 minor and no major adverse events. This study is the first to demonstrate the feasibility and safety of a full-scale extended thromboprophylaxis RCT in thoracic surgical oncology. Our results demonstrate that, while recruitment and retention rates were modest, the study design is feasible and with minimal adverse events and no intervention-related mortality.

New and emerging anticoagulant therapies for venous thromboembolism.

OPINION STATEMENT: Anticoagulation therapy remains the cornerstone for prevention and treatment of venous thromboembolism. Currently available parenteral anticoagulants, such as heparin, low molecular weight heparin, and fondaparinux, are used widely for short-term therapy, but the need for parenteral administration limits their utility for long-term use. Vitamin K antagonists, such as warfarin, are the only oral anticoagulants available for long-term use. Although effective, these drugs produce a variable anticoagulant response and require routine coagulation monitoring and frequent dose adjustments. New anticoagulants that can be given in fixed doses without monitoring have been developed to overcome the limitations of existing agents. These drugs are in advanced stages of development and have the potential to streamline the prevention and treatment of venous thromboembolism.