Bleeding Risk Prediction in Patients Treated with Antithrombotic Drugs According to the Anatomic Site of Bleeding, Indication for Treatment, and Time Since Treatment Initiation.

Background Reasons for the relatively poor performance of bleeding prediction models are not well understood but may relate to differences in predictors for various anatomical sites of bleeding. Methods We pooled individual participant data from four randomized controlled trials of antithrombotic therapy in patients with coronary and peripheral artery diseases, embolic stroke of undetermined source (ESUS), or atrial fibrillation. We examined discrimination and calibration of models for any major bleeding, major gastrointestinal (GI) bleeding, and intracranial hemorrhage (ICH), according to the time since initiation of antithrombotic therapy, and indication for antithrombotic therapy. Results Of 57,813 patients included, 1,948 (3.37%) experienced major bleeding, including 717 (1.24%) major GI bleeding and 274 (0.47%) ICH. The model derived to predict major bleeding at 1 year from any site (c-index, 0.69, 95% confidence interval [CI], 0.68-0.71) performed similarly when applied to predict major GI bleeding (0.71, 0.69-0.74), but less well to predict ICH (0.64, 0.61-0.69). Models derived to predict GI bleeding (0.75, 0.74-0.78) and ICH (0.72, 0.70-0.79) performed better than the general major bleeding model. Discrimination declined over time since the initiation of antithrombotic treatment, stabilizing at approximately 2 years for any major bleeding and major GI bleeding and 1 year for ICH. Discrimination was best for the model predicting ICH in the ESUS population (0.82, 0.78-0.92) and worst for the model predicting any major bleeding in the coronary and peripheral artery disease population (0.66, 0.65-0.69). Conclusion Performance of risk prediction models for major bleeding is affected by site of bleeding, time since initiation of antithrombotic therapy, and indication for antithrombotic therapy.

Anticoagulation Stewardship to Bridge the Implementation Gap in Perioperative Anticoagulation Management.

Lack of alignment of care protocols among providers in health care is a driver of increased costs and suboptimal patient outcomes. Perioperative anticoagulation management is a good example of a complex area where protocol creation is a clinical challenge that demands input from multiple experts. Questions regarding the need for anticoagulation interruptions are frequent. Yet, due to layers of complexity involving analysis of anticoagulation indication, surgical risk, and anesthesia-associated bleeding risk as well as institutional practices, there is heterogeneity in how these interruptions are approached. The recent perioperative anticoagulation guidelines from the American College of Chest Physicians summarize extensive evidence for the management of anticoagulant and antiplatelet medications in patients who undergo elective interventions. However, implementation of these guidelines by individual clinicians is highly varied and often does not follow the best available clinical evidence. Against this background, anticoagulation stewardship units, which exist to improve safety and quality monitoring for the anticoagulated patient, are of growing interest. These units provide a bridge for the implementation of value-based, high-quality guidelines for patients who need perioperative anticoagulation interruption. We use a case to pragmatically illustrate the problem and tactics for change management and implementation science that may facilitate the adoption of perioperative anticoagulation guidelines.

Strategies to reduce out-of-pocket medication costs for Canadians with peripheral arterial disease.

BACKGROUND: Given that peripheral arterial disease (PAD) disproportionately affects people of lower socioeconomic status, out-of-pocket expenses for preventive medications are a major barrier to their use. We carried out a cost comparison of drug therapies for PAD to identify prescribing strategies that minimize out-of-pocket expenses for these medications. METHODS: Between March and June 2019, we contacted outpatient pharmacies in Hamilton, Ontario, Canada, to assess pricing of pharmacologic therapies at dosages included in the 2016 American College of Cardiology/American Heart Association guideline for management of lower extremity PAD. We also gathered pricing information for supplementary charges, including delivery, pill splitting and blister packaging. We calculated prescription prices with and without dispensing fees for 30-day brand-name and generic prescriptions, and 90-day generic prescriptions. RESULTS: Twenty-four pharmacies, including hospital-based, independent and chain, were included in our sample. In the most extreme scenario, total 90-day medication costs could differ by up to $1377.26. Costs were affected by choice of agent within a drug class, generic versus brand-name drug, quantity dispensed, dispensing fee and delivery cost, if any. CONCLUSION: By opting for prescriptions for 90 days or as long as possible, selecting the lowest-cost generic drugs available in each drug class, and identifying dispensing locations with lower fees, prescribers can minimize out-of-pocket patient medication expenses. This may help improve adherence to guideline-recommended therapies for the secondary prevention of vascular events in patients with PAD.

Clinical Studies with Anticoagulants that Have Changed Clinical Practice.

Anticoagulant therapy is the cornerstone of treatment and prevention of arterial and venous thromboembolism. Taking a historical perspective, starting in the 1960s, and progressing through to 2022, we discuss key clinical trials of anticoagulants that have changed clinical practice, and examine obstacles encountered in bringing these anticoagulants to the clinic. The design of some of the early studies that shaped clinical practice was poor by current standards, but their results were influential because nothing better was available. Both heparin and vitamin K antagonists had been in clinical use for several decades before well-designed trials in the 1980s optimized their dosing and enhanced their safety and efficacy. Low-molecular-weight heparin then replaced unfractionated heparin because it had a more predictable dose-response and a longer half-life, thereby allowing it to be used conveniently in out-of-hospital settings. More recently, direct oral anticoagulants became the oral anticoagulants of choice for most indications because they were shown to be at least as safe and effective as vitamin K antagonists when used in fixed doses without the need for laboratory monitoring. The design of the trials that led to the approval of the direct oral anticoagulants was excellent, but further studies are required to optimize their dosing in selected patients who were underrepresented in these trials.

Impact of Rabeprazole on APO-Dabigatran Exposure in Healthy Volunteers.

Background: Dabigatran is effective and safe for stroke prevention in patients with atrial fibrillation and for venous thromboembolism prevention and treatment. In Canada, APO-dabigatran, a generic formulation, has been approved based on a bioequivalence study, but its bioavailability in settings of reduced gastric acidity has not been examined. Methods: Treatment With APO-Dabigatran Absorption (TADA) was an open-label crossover study in 46 healthy male volunteers, comparing the absorption of APO-dabigatran (150 mg) with vs without rabeprazole. The primary outcome was the 24-hour total dabigatran exposure as measured by area under the curve (AUC) and peak concentration (Cmax). Results: Compared with no rabeprazole pretreatment, the total dabigatran AUC (geometric mean [gmean] AUC0-tz: 567.2 vs 804 ngh/mL, and gmean AUC0-∞: 609.7 vs 804) and Cmax (gmean: 64.1 vs 104.4 ng/mL) were significantly reduced with rabeprazole. The percent gmean ratios for AUC0-tz, AUC0-∞, and Cmax (with rabeprazole vs without) were 70.5% (95% confidence interval [CI]: 51.9% to 95.7%), 71.8% (95% CI: 53.1% to 96.9%), and 61.4% (95% CI: 44.1% to 85.5%), respectively. With rabeprazole, the proportions of participants with > 50% reduction in AUC0-tz, AUC0-∞, and Cmax were 32.6%, 30.4%, and 39.1%, respectively. Conclusions: When APO-dabigatran is administered with rabeprazole, the exposure to dabigatran is reduced by about 30%, which is similar to the level observed with Pradaxa when it was co-administered with a proton pump inhibitor. However, the finding that one-third of participants had a > 50% reduction in exposure is concerning, and it highlights the need for caution in patients who have, or are at risk of, reduced gastric acidity.

Contexte: Le dabigatran est une option thérapeutique sûre et efficace pour prévenir les accidents vasculaires cérébraux chez les patients atteints de fibrillation auriculaire et pour prévenir et traiter les thromboembolies veineuses. Au Canada, APO-dabigatran (une version générique) a été homologué sur la base d'une étude de bioéquivalence, mais sa biodisponibilité en contexte d'acidité gastrique réduite n'a pas été évaluée. Méthodologie: L'étude TADA ( T reatment with A PO- D abigatran A bsorption) est une étude croisée menée en mode ouvert auprès de 46 hommes volontaires en bonne santé, afin de comparer l'absorption d'APO-dabigatran (à 150 mg) avec et sans rabéprazole. Le critère d'évaluation principal était l'exposition totale sur 24 heures au dabigatran, telle que mesurée par la surface sous la courbe (SSC) et la concentration maximale (Cmax). Résultats: Par rapport à une administration sans prétraitement par rabéprazole, une réduction significative de la SSC totale du dabigatran (moyenne géométrique [MG] SSC0-tz : 567,2 par rapport à 804 ngh/ml; MG SSC0-∞ : 609,7 par rapport à 804 ngh/ml) et de la Cmax (MG : 64,1 par rapport à 104,4 ng/ml) a été observée avec la prise de rabéprazole. Les ratios des MG en pourcentage de la SSC0-tz, de la SSC0-∞, et de la Cmax (avec et sans rabéprazole) étaient de 70,5 % (intervalle de confiance [IC] à 95 % : 51,9 % à 95,7 %), 71,8 % (IC à 95 % : 53,1 % à 96,9 %) et 61,4 % (IC à 95 % : 44,1 % à 85,5 %), respectivement. Les proportions de participants chez qui une réduction de > 50 % de la SSC0-tz, de la SSC0-∞ ou de la Cmax a été notée avec l'administration du rabéprazole s'élevaient à 32,6 %, 30,4 % et 39,1 %, respectivement. Conclusions: Lors de l'administration d'APO-dabigatran en concomitance avec le rabéprazole, l'exposition au dabigatran était réduite d'environ 30 %, une valeur comparable à la réduction observée lors de l'administration de Pradaxa en concomitance avec un inhibiteur de la pompe à protons. La réduction de > 50 % de l'exposition médicamenteuse chez le tiers des participants n'en est pas moins préoccupante et démontre la nécessité de faire preuve de prudence lorsque l'acidité gastrique est réduite ou risque d'être réduite chez un patient.

Multidisciplinary Practice Variations of Anti-Thrombotic Strategies for Free Tissue Transfers.

Background: Venous thrombosis, the leading cause of free flap failure, may have devastating consequences. Many anti-thrombotic agents and protocols have been described for prophylaxis and treatment of venous thrombosis in free flaps. Methods: National surveys were distributed to microsurgeons (of both Plastics and ENT training) and hematology and thrombosis specialists. Data were collected on routine screening practices, perceived risk factors for flap failure, and pre-, intra-, and post-operative anti-thrombotic strategies. Results: There were 722 surveys distributed with 132 (18%) respondents, consisting of 102 surgeons and 30 hematologists. Sixty-five surgeons and 9 hematologists routinely performed or managed patients with free flaps. The top 3 perceived risk factors for flap failure according to surgeons were medical co-morbidities, past arterial thrombosis, and thrombophilia. Hematologists, however, reported diabetes, smoking, and medical co-morbidities as the most important risk factors. Fifty-four percent of physicians routinely used unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) as a preoperative agent. Surgeons routinely flushed the flap with heparin (37%), used UFH IV (6%), or both (8%) intra-operatively. Surgeons used a range of post-operative agents such as UFH, LMWH, aspirin, and dextran while hematologists preferred LMWH. There was variation of management strategies if flap thrombosis occurred. Different strategies consisted of changing recipient vessels, UFH IV, flushing the flap, adding post-operative agents, or a combination of strategies. Conclusions: There are diverse practice variations in anti-thrombotic strategies for free tissue transfers and a difference in perceived risk factors for flap failure that may affect patient management.

Contexte: La thrombose veineuse, principale cause de l'échec des volets libres, peut avoir des conséquences catastrophiques. De nombreux agents et protocoles antithrombotiques ont été décrits pour la prévention et le traitement de la thrombose veineuse dans les volets libres. Méthodes: Des enquêtes nationales ont été distribuées à des chirurgiens spécialistes de microchirurgie (ayant à la fois une formation en chirurgie plastique et ORL) et à des spécialistes en hématologie et thrombose. Les données collectées ont porté sur les pratiques usuelles de sélection, les facteurs de risque perçus d'échec des volets, ainsi que sur les stratégies antithrombotiques pré-, per- et postopératoires. Résultats: Sur les 722 enquêtes distribuées, il y a eu 132 répondants (18 %) consistant en 102 chirurgiens et 30 hématologistes. Soixante-cinq chirurgiens et neuf hématologues réalisent ou gèrent régulièrement des patients avec des volets libres. Les trois plus importants facteurs de risque perçus d'échec du volet, selon les chirurgiens, étaient les comorbidités médicales, un antécédent de thrombose artérielle et la thrombophilie. De leur côté, les hématologues ont indiqué que le diabète, le tabagisme et les comorbidités médicales étaient les facteurs de risque les plus importants. Cinquante-quatre pour cent des médecins utilisent régulièrement de l'héparine non fractionnée ou de l'héparine de bas poids moléculaire (HBPM) comme agent préopératoire. Les chirurgiens rincent régulièrement le volet à l'héparine (37 %), utilisent de l'héparine non fractionnée par voie IV (6 %) ou les deux (8 %) en peropératoire. Les chirurgiens utilisent un éventail d'agents postopératoires, tels que l'héparine non fractionnée, l'HBPM, l'aspirine et le dextran tandis que les hématologues préfèrent l'HBPM. Des variations dans les stratégies de gestion ont été observées en cas de survenue d'une thrombose du volet. Différentes stratégies ont consisté à changer les vaisseaux receveurs, administrer de l'héparine non fractionnée IV, rincer le volet, ajouter des agents postopératoires, ou combiner ces stratégies. Conclusions: Il y a différentes variations dans la pratique de stratégies antithrombotiques pour les transferts de tissus libres et une différence dans les facteurs de risque perçus d'échec du volet qui peuvent avoir des répercussions sur la gestion des patients.

Patient and physician perspectives on the use and outcome measures of mHealth apps: Exploratory survey and focus group study.

Objective: Factors that physicians and patients consider when making decisions about using or recommending health apps are not well understood. We explored these factors to better assess how to support such decision making. Methods: We conducted an exploratory cross-sectional study in Ontario using qualitative focus groups and quantitative surveys. 133 physicians and 94 community dwelling adults completed online surveys and we held two focus groups of nine community dwelling participants who had cardiovascular risk factors and an interest in using mHealth apps. Quantitative survey data was analyzed descriptively. Focus groups were audio-recorded and transcribed verbatim prior to inductive thematic content analysis. We integrated the results from the surveys and focus groups to understand factors that influence physicians' and patients' selection and use of such apps. Results: Physicians recommend apps to patients but the level of evidence they prefer to use to guide selection did not align with what they were currently using. Patients trusted recommendations and reviews from medical organizations and healthcare professionals when selecting apps and were motivated to continue using apps when they supported goal setting and tracking, data sharing, decision making, and empowerment. Conclusions: The findings highlight the significance of evaluating mHealth apps based on metrics that patients and physicians value beyond usage and clinical outcome data. Patients engage with apps that support them in confidently managing their health. Increased training and awareness of apps and creating a more rigorous evidence base showing the value of apps to supporting health goals will support greater adoption and acceptance of mHealth apps.

Carbamazepine, phenytoin, and oral anticoagulants: Drug-drug interaction and clinical events in a retrospective cohort.

BACKGROUND: Carbamazepine and phenytoin are potent inducers of enzymes that metabolize oral anticoagulants. OBJECTIVES: To determine the clinical impact of drug-drug interactions between these anticonvulsants and oral anticoagulants, and whether they affect the treatment with direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs). MATERIAL AND METHODS: Data on patients cotreated with carbamazepine or phenytoin and an oral anticoagulant were retrospectively retrieved from medical records from 2011 to 2020. Outcomes were time in therapeutic range (TTR), DOAC levels, thromboembolic events, major bleeding, and all-cause mortality. RESULTS: Among 85 patients (37% female, median age 68 years) treated with carbamazepine (n = 43 [51%]) or phenytoin (n = 42 [49%]), 53 (62%) were initially treated with VKAs and 32 (38%) with DOACs. TTR in VKA patients was 63%, which improved in year 2. Four of seven trough and five of 12 peak DOAC plasma levels were lower than expected. The incidence rate (95% confidence interval) per 100 person-years for thromboembolism was 3.6 (3.1-4.2) for VKA patients and 4.4 (3.5-5.6) for DOAC patients; for major bleeding 1.8 (1.5-2.1) and 1.5 (1.2-1.9), and for all-cause mortality 3.6 (3.1-4.2) and 1.5 (1.2-1.9), respectively. Incidence rates between VKAs and DOACs and between carbamazepine and phenytoin were similar. CONCLUSION: There was a high incidence of thromboembolism in patients cotreated with anticoagulants and carbamazepine or phenytoin. The incidence rates of thrombotic and bleeding events were similar between VKA and DOAC patients. DOAC levels were lower than expected in 47% of cases tested, without correlation with clinical outcomes.

Building Your Peripheral Artery Disease Toolkit: Medical Management of Peripheral Artery Disease in 2022.

Peripheral artery disease (PAD) is associated with substantial morbidity, including a high risk of cardiovascular and limb events and death. A growing body of evidence has demonstrated the benefits of antithrombotic therapy, lipid lowering, blood pressure control, diabetes management, smoking cessation, and exercise programs on improving symptoms and reducing these complications. Guidelines make specific recommendations on how to use these strategies to prevent adverse cardiovascular and limb outcomes in patients with PAD. Unfortunately, antithrombotic therapies, statins, optimal antihypertensives, smoking cessation counselling and therapies, and exercise programs have all been consistently shown to be underutilised in PAD patients both in Canada and globally. A variety of barriers to optimal utilisation of evidence-based medical therapies have been described at the patient, health care provider, and system levels. These include lack of knowledge among patients and health care providers, and lack of access to secondary prevention programs. We review the evidence for preventive therapies in PAD, evidence for underutilisation of these therapies, and barriers to their use. Core elements of PAD secondary prevention clinics are proposed, and a summary of optimal medical therapies and relevant tools is provided. This review may help clinicians who treat patients with PAD to develop a toolkit to overcome these barriers in order to improve utilisation of medical therapies, with the ultimate goal of improving outcomes for PAD patients.

Can a Single Measurement of Apixaban Levels Identify Patients at Risk of Overexposure? A Prospective Cohort Study.

Background Patients with atrial fibrillation (AF) are frequently treated with apixaban 2.5-mg twice daily (BID) off-label, presumably to reduce the bleeding risk. However, this approach has the potential to increase the risk of ischemic stroke. If a single measurement could reliably identify patients with high drug levels, the increased stroke risk may be mitigated by confining off-label dose reduction to such patients. Objectives This study aimed to determine whether a single high apixaban level is predictive of a similarly high level when the test is repeated in 2 months. Methods In this prospective cohort study of clinic patients receiving apixaban 5-mg BID for AF or venous thromboembolism, peak and trough apixaban levels were measured using the STA-Liquid anti-Xa assay at baseline and 2 months. We calculated the proportions of patients with levels that remained in the upper quintile. Results Of 100 enrolled patients, 82 came for a second visit, 55 of whom were treated with apixaban 5-mg BID. Seven (63.6%, 95% confidence interval [CI]: 35.4-84.8%) and nine (81.8%, 95% CI: 52.3-94.9%) of 11 patients with a baseline trough and peak level in the upper quintile, respectively, had a subsequent level that remained within this range. Only one (9.1%, 95% CI: 1.6-37.7%) patient had a subsequent level that fell just lower than the median. Conclusion The trough and peak levels of apixaban in patients who have a high level on a single occasion, usually remain high when the assay is repeated in 2 months. Accordingly, the finding of a high apixaban level in patients deemed to be at high risk of bleeding, allows physicians contemplating off-label use of the 2.5-mg BID dose to limit its use to selected patients who are less likely to be exposed to an increased risk of thrombosis.

Medical Therapy Following Urgent/Emergent Revascularization in Peripheral Artery Disease Patients (Canadian Acute Limb Ischemia Registry [CANALISE I]).

BACKGROUND: Following severe limb ischemia requiring urgent/emergent revascularization, peripheral arterial disease patients suffer a high risk of recurrent atherothrombosis. METHODS: Patients discharged from Hamilton General Hospital (Hamilton, Ontario) between April 2016 and September 2017 following severe limb ischemia requiring urgent/emergent revascularization were identified via the Local Health Integration Network CorHealth database, with supplemental information from chart review. RESULTS: A total of 158 patients admitted for urgent/emergent revascularization were identified (148 alive at discharge). Among patients without a pre-existing indication for anticoagulation, 38.8% (n = 47) were discharged on single-antiplatelet therapy, 27.3% (n = 33) on dual-antiplatelet therapy, 19.8% (n = 24) on anticoagulants plus antiplatelet therapy, 6.6% (n = 8) on anticoagulants alone, and 2.6% (n = 3) on unknown therapy. Patients who received angioplasty with stenting were more likely be discharged on dual-antiplatelet therapy (hazard ratio [HR]: 7.14; 95% confidence interval [CI]: 2.87-17.76; P < 0.01); patients who received an embolectomy/thrombectomy were more likely be discharged on an anticoagulant alone (HR: 2.61; 95% CI: 1.00-6.81; P = 0.049); and patients who received peripheral bypass grafting were more likely be discharged on single-antiplatelet therapy (HR: 2.28; 95% CI: 1.11-4.69; P = 0.024). Neither statins (60.8% vs 56.3%; P = 0.23) nor renin-angiotensin-aldosterone system inhibitors (48.7% vs 50.6%; P = 0.58) were prescribed at higher rates at discharge, compared with the rate at admission. CONCLUSIONS: Substantial heterogeneity exists in antithrombotic prescription following urgent/emergent revascularization. No intensification of non-antithrombotic vascular protective medications occurred during hospitalization. Clinical trials and health system interventions to optimize medical therapy in peripheral arterial disease patients are urgently needed.

INTRODUCTION: Après une ischémie grave d'un membre ayant nécessité une revascularisation urgente/nouvelle revascularisation, les patients atteints d'une maladie artérielle périphérique ont un risque élevé de récidive d'athérothrombose. MÉTHODES: Nous avons recensé les patients qui ont obtenu leur sortie de la Hamilton General Hospital (Hamilton, Ontario) entre avril 2016 et septembre 2017 à la suite d'une ischémie grave d'un membre ayant nécessité une revascularisation urgente/nouvelle revascularisation via la base de données Local Health Integration Network CorHealth et grâce aux renseignements complémentaires issus de la revue des dossiers. RÉSULTATS: Nous avons recensé un total de 158 patients admis pour une revascularisation urgente/nouvelle revascularisation (148 patients en vie à la sortie de l'hôpital). Parmi les patients chez lesquels l'anticoagulation n'avait pas antérieurement été indiquée, 38,8 % (n = 47) avaient reçu à leur sortie de l'hôpital un simple traitement antiplaquettaire; 27,3 % (n = 33), une bithérapie antiplaquettaire; 19,8 % (n = 24), des anticoagulants plus un traitement antiplaquettaire; 6,6 % (n = 8), des anticoagulants seuls; 2,6 % (n = 3), un traitement inconnu. Les patients qui avaient subi une angioplastie et une pose d'endoprothèse étaient plus susceptibles d'obtenir à leur sortie de l'hôpital une bithérapie antiplaquettaire (rapport de risque [RR] : 7,14; intervalle de confiance [IC] à 95 % : 2,87-17,76; P < 0,01); les patients qui avaient subi une embolectomie, ou thrombectomie, étaient plus susceptibles d'obtenir à leur sortie de l'hôpital un anticoagulant seul (RR : 2,61; IC à 95 % : 1,00-6,81; P = 0,049); les patients qui avaient subi un pontage périphérique étaient plus susceptibles d'obtenir à leur congé de l'hôpital un simple traitement antiplaquettaire (RR : 2,28; IC à 95 % : 1,11-4,69; P = 0,024). Comparativement à l'admission, ni les statines (60,8 % vs 56,3 %; P = 0,23) ni les inhibiteurs du système rénine­angiotensine­aldostérone (48,7 % vs 50,6 %; P = 0,58) n'avaient été prescrits à des taux plus élevés à la sortie de l'hôpital. CONCLUSIONS: Nous observons une hétérogénéité substantielle de l'ordonnance des antithrombotiques après la revascularisation urgente/nouvelle revascularisation. L'hospitalisation n'a donné lieu à aucune augmentation des médicaments de protection vasculaire non antithrombotiques. Des essais cliniques et des interventions du système de santé qui permettent d'optimiser le traitement médical des patients atteints d'une maladie artérielle sont d'une urgente nécessité.

Plasma Rivaroxaban Level to Identify Patients at Risk of Drug Overexposure: Is a Single Measurement of Drug Level Reliable?

Introduction Dose adjustment based on laboratory monitoring is not routinely recommended for patients treated with rivaroxaban but because an association has been reported between high drug level and bleeding, it would be of interest to know if measuring drug level once could identify patients at risk of bleeding who might benefit from a dose reduction. Objective This study was aimed to investigate the reliability of a single measurement of rivaroxaban level to identify clinic patients with persistently high levels, defined as levels that remained in the upper quintile of drug-level distribution. Methods In this prospective cohort study of 100 patients with atrial fibrillation or venous thromboembolism, peak and trough rivaroxaban levels were measured using the STA-Liquid Anti-Xa assay at baseline and after 2 months. Values of 395.8 and 60.2 ng/mL corresponded to the 80th percentile for peak and trough levels, respectively, and levels above these cut-offs were categorized as high for our analyses. Results Among patients with a peak or trough level in the upper quintile at baseline, only 26.7% (95% confidence interval [CI]: 10.9-52.0%), and 13.3% (95% CI: 2.4-37.9%), respectively, remained above these thresholds. Conclusion Our findings do not support the use of a single rivaroxaban level measurement to identify patients who would benefit from a dose reduction because such an approach is unable to reliably identify patients with high levels.

Prevention and Management of Urgent/Emergent Limb Ischemia.

PURPOSE OF REVIEW: Patients who require urgent or emergent peripheral revascularization represent one of the highest risk subgroups of PAD patients. They suffer unacceptably high complication rates including recurrent ALI, vascular amputation, and death. In this article, we examine (1) the burden of cardiovascular complications according to PAD severity, (2) discuss medical optimization to improve vascular outcomes in symptomatic LE-PAD patients, and (3) review the evidence for management of patients following urgent/emergent limb ischemia. RECENT FINDINGS: The VOYAGER trial recently demonstrated that rivaroxaban 2.5 mg BID + ASA daily significantly reduces major adverse cardiac and limb events in patients following lower extremity revascularization. A recent Canadian survey also demonstrated that significant heterogeneity exists in antithrombotic prescribing practices following urgent/emergent revascularization. COMPASS and VOYAGER have demonstrated the efficacy of aspirin 81 mg daily and rivaroxaban 2.5 mg twice daily at reducing MACE and MALE events in stable PAD patients and those undergoing elective revascularization. Patients who require urgent or emergent peripheral revascularization remain the highest thrombotic risk subgroup of PAD patients, in whom there is insufficient evidence to guide antithrombotic therapy. Despite clear evidence that multi-modal medical therapy (including statins, antihypertensive agents and smoking cessation) benefits patients with atherosclerosis, their use remains unacceptably low in PAD, and greater efforts are needed to understand and address patient, health provider, and system issues that prevent their optimal implementation in practice.

Feasibility of a Web-Based Platform (Trial My App) to Efficiently Conduct Randomized Controlled Trials of mHealth Apps For Patients With Cardiovascular Risk Factors: Protocol For Evaluating an mHealth App for Hypertension.

BACKGROUND: Mobile health (mHealth) interventions can improve health by improving cardiovascular risk factors, but their adoption in care by physicians and patients is untapped. Few mHealth apps have been evaluated in clinical trials, and due to the fast pace of technological development, those previously evaluated are often outdated by the time trial results are available. Given the rapid pace of change in this field, it is not feasible to rigorously evaluate mHealth apps with current methodologies. OBJECTIVE: The overall aim of this pilot study was to test the feasibility of using a web research platform called Trial My App to conduct efficient and rigorous web-based randomized controlled trials (RCTs) of mHealth apps relevant to patients with cardiovascular risk factors by evaluating an app that targets hypertension. METHODS: For this study, 200 participants with suboptimally controlled hypertension will be recruited through advertisements in newsletters, media, and the internet, as well as through referrals from their health care providers. Screening, consent, randomization, and collection of patient-important health confidence and self-management ability outcomes will be conducted online through the Trial My App research platform. Participants will be randomized into 2 groups: 100 that will use an mHealth app for tracking hypertension and 100 that will be considered as an educational control. All participants will complete questionnaires at 0, 1, 3 and 6 months after enrolment. A substudy to validate the method of blood pressure readings and the consistency of data entered through Trial My App will be conducted with 40 participants. RESULTS: The development of the Trial My App web platform has been completed. The creation of survey instruments has been completed in collaboration with our patient partners and advisory board. Recruitment is expected to begin in the first quarter of 2021; data collection and analysis are expected to be completed approximately 1 year after study commencement. Results will be disseminated through conferences and publications. The primary outcomes of this study include the feasibility of conducting an RCT using the Trial My App platform by reporting recruitment, retention, and completion statistics. We will validate app-entered data with a standard 7-day home blood pressure measurement method. Lastly, the pilot, nonblinded RCT will assess the effectiveness of the mHealth app in improving the control of hypertension compared with the control of hypertension in the educational control group. CONCLUSIONS: This study will determine if it is feasible to use the Trial My App web-based platform to evaluate the effectiveness of mHealth apps for patients with cardiovascular risk factors. As more mHealth apps are evaluated in RCTs, patients will be able to select apps that meet their needs and physicians will be able to make evidence-based recommendations to their patients for apps aimed at improving cardiovascular health. TRIAL REGISTRATION: ClinicalTrials.gov NCT04528654; https://clinicaltrials.gov/ct2/show/NCT04528654. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/26155.

A National Canadian Survey of Antithrombotic Therapy After Urgent and Emergent Limb Revascularization.

Patients with peripheral artery disease who undergo urgent or emergent lower extremity revascularization have the highest risk of major adverse cardiac and limb events. Although available evidence suggests that antithrombotic therapy reduces this risk, optimal antithrombotic therapy is unclear. In this report, we aim to describe current practice patterns for use of antithrombotic therapies after urgent/emergent peripheral artery revascularization. A self-administered online survey was distributed to all active vascular surgeons registered through the Canadian Society of Vascular Surgery (n = 149) between March 19 and April 29, 2019. The overall response rate was 53% (79/149). More than half of the respondents use a medical specialist service in aiding decision-making (52% (95% confidence interval [CI], 40.9%-63.0%). When concerned for high rethrombosis risk, respondents most commonly favoured initiation of either aspirin plus full dose anticoagulation (60% [95% CI, 49.2%-70.8%]) or dual antiplatelet therapy (58% (95% CI, 47.1%-68.9%]). Intraoperative findings and patient characteristics prompting concern for high rethrombosis risk include residual proximal/distal occlusive disease (75% [95% CI, 65.5%-84.5%]), poor-quality venous conduit (76% [95% CI, 66.6%-85.4%]), distal/infrapopliteal synthetic conduit (77% [95% CI, 67.7%-86.3%]), and history of multiple previous failed vascular interventions (98% [95% CI, 94.9%-100%]). More than 90% of respondents believe significant uncertainty exists in antithrombotic decision-making after urgent/emergent peripheral revascularization. Substantial uncertainty exists regarding antithrombotic therapy after urgent/emergent revascularization. In patients at high perceived rethrombosis risk, vascular surgeons preferentially choose aspirin with full-dose anticoagulation or dual antiplatelet therapy. Because of the clinical uncertainty in this domain, trials to determine optimal antithrombotic therapy in this high-risk population are required.

Mortality benefit in the COMPASS trial: is it related to superior statistical power or better efficacy and safety?

Until recently, attempts to improve the benefit of aspirin by adding another antithrombotic agent have not resulted in a mortality reduction in patients with chronic symptomatic atherosclerosis. In this population, COMPASS is the only one among six trials to show a significant mortality reduction, thereby providing evidence of a clear net clinical benefit with the combination of low-dose rivaroxaban plus aspirin. In this systematic review, we sought to determine whether the mortality benefit of the combination arm in COMPASS is best explained by greater statistical power or by a more favorable efficacy-safety profile than the other regimens evaluated in patients with chronic symptomatic atherosclerosis.

Current Challenges in Diagnosis of Venous Thromboembolism.

In patients with suspected venous thromboembolism, the goal is to accurately and rapidly identify those with and without thrombosis. Failure to diagnose venous thromboembolism (VTE) can lead to fatal pulmonary embolism (PE), and unnecessary anticoagulation can cause avoidable bleeding. The adoption of a structured approach to VTE diagnosis, that includes clinical prediction rules, D-dimer testing and non-invasive imaging modalities, has enabled rapid, cost-effective and accurate VTE diagnosis, but problems still persist. First, with increased reliance on imaging and widespread use of sensitive multidetector computed tomography (CT) scanners, there is a potential for overdiagnosis of VTE. Second, the optimal strategy for diagnosing recurrent leg deep venous thrombosis remains unclear as is that for venous thrombosis at unusual sites. Third, the conventional diagnostic approach is inefficient in that it is unable to exclude VTE in high-risk patients. In this review, we outline pragmatic approaches for the clinician faced with difficult VTE diagnostic cases. In addition to discussing the principles of the current diagnostic framework, we explore the diagnostic approach to recurrent VTE, isolated distal deep-vein thrombosis (DVT), pregnancy associated VTE, subsegmental PE, and VTE diagnosis in complex medical patients (including those with impaired renal function).

Prevention of Venous Thromboembolism in 2020 and Beyond.

Venous thromboembolism (VTE) is the third most common cause of vascular mortality worldwide and comprises deep-vein thrombosis (DVT) and pulmonary embolism (PE). In this review, we discuss how an understanding of VTE epidemiology and the results of thromboprophylaxis trials have shaped the current approach to VTE prevention. We will discuss modern thromboprophylaxis as it pertains to genetic risk factors, exogenous hormonal therapies, pregnancy, surgery, medical hospitalization, cancer, and what is known thus far about VTE in COVID-19 infection.