Association of Adding Aspirin to Warfarin Therapy Without an Apparent Indication With Bleeding and Other Adverse Events

Drug response-based precision therapeutic selection for tamoxifen-resistant triple-positive breast cancer

Breast cancer adaptability to the drug environment reduces the chemotherapeutic response and facilitates acquired drug resistance. Cancer-specific therapeutics can be more effective against advanced-stage cancer than standard chemotherapeutics. To extend the paradigm of cancer-specific therapeutics, clinically relevant acquired tamoxifen-resistant MCF-7 proteome was deconstructed to identify possible druggable targets (N = 150). Twenty-eight drug inhibitors were used against identified druggable targets to suppress non-resistant (NC) and resistant cells (RC). First, selected drugs were screened using growth-inhibitory response against NC and RC. Seven drugs were shortlisted for their time-dependent (10-12 days) cytotoxic effect and further narrowed to three effective drugs (e.g., cisplatin, doxorubicin, and hydroxychloroquine). The growth-suppressive effectiveness of selected drugs was validated in the complex spheroid model (progressive and regressive). In the progressive model, doxorubicin (RC: 83.64 %, NC: 54.81 %), followed by cisplatin (RC: 76.66 %, NC: 68.94 %) and hydroxychloroquine (RC: 68.70 %, NC: 61.78 %) showed a significant growth-suppressive effect. However, in fully grown regressive spheroid, after 4th drug treatment, cisplatin significantly suppressed RC (84.79 %) and NC (40.21 %), while doxorubicin and hydroxychloroquine significantly suppressed only RC (76.09 and 76.34 %). Our in-depth investigation effectively integrated the expression data with the cancer-specific therapeutic investigation. Furthermore, our three-step sequential drug-screening approach unbiasedly identified cisplatin, doxorubicin, and hydroxychloroquine as an efficacious drug to target heterogeneous cancer cell populations. SIGNIFICANCE STATEMENT: Hormonal-positive BC grows slowly, and hormonal-inhibitors effectively suppress the oncogenesis. However, development of drug-resistance not only reduces the drug-response but also increases the chance of BC aggressiveness. Further, alternative chemotherapeutics are widely used to control advanced-stage BC. In contrast, we hypothesized that, compared to standard chemotherapeutics, cancer-specific drugs can be more effective against resistant-cancer. Although cancer-specific treatment identification is an uphill battle, our work shows proteome data can be used for drug selection. We identified multiple druggable targets and, using ex-vivo methods narrowed multiple drugs to disease-condition-specific therapeutics. We consider that our investigation successfully interconnected the expression data with the functional disease-specific therapeutic investigation and selected drugs can be used for effective resistant treatment with higher therapeutic response.

Management of atrial fibrillation in older adults

Most people with atrial fibrillation are older adults, in whom atrial fibrillation co-occurs with other chronic conditions, polypharmacy, and geriatric syndromes such as frailty. Yet most randomized controlled trials and expert guidelines use an age agnostic approach. Given the heterogeneity of aging, these data may not be universally applicable across the spectrum of older adults. This review synthesizes the available evidence and applies rigorous principles of aging science. After contextualizing the burden of comorbidities and geriatric syndromes in people with atrial fibrillation, it applies an aging focused approach to the pillars of atrial fibrillation management, describing screening for atrial fibrillation, lifestyle interventions, symptoms and complications, rate and rhythm control, coexisting heart failure, anticoagulation therapy, and left atrial appendage occlusion devices. Throughout, a framework is suggested that prioritizes patients' goals and applies existing evidence to all older adults, whether atrial fibrillation is their sole condition, one among many, or a bystander at the end of life.

Mechanical valve thrombosis: Current management and differences between guidelines

All foreign bodies inserted in the circulatory system are thrombogenic and require temporary or lifelong antithrombotic therapies to prevent thrombosis. The adequate level of anticoagulation during the first few months determines the long-term durability, particularly for mechanical prostheses, and also for biological valves. Suboptimal anticoagulation is the most frequent source of mechanical valve thrombosis (MVT). The patient's clinical presentation decides how mechanical prosthetic valve obstruction is managed. If the mechanical valve thrombosis is obstructive and the patient is in a critical condition with hemodynamic instability, an immediate surgical intervention should be performed. The thrombolytic treatment is an option for left mechanical valve thrombosis in patients who have high surgical risk and no contraindications and also for right heart valve thrombosis. In non-obstructive thrombosis on the mechanical valve, patients can be asymptomatic, requiring optimization of the anticoagulant treatment. Both obstructive and non-obstructive thrombus formed on the mechanical prosthesis can result in embolic events. If the thrombus persists following anticoagulant treatment, the recommended options include thrombolytic treatment or redo surgery. Pannus can also cause obstruction of the prosthesis for which surgical treatment is the only option. While these clinical scenarios may initially appear to have straightforward solutions in terms of surgery, thrombolysis, or effective anticoagulation, real-world clinical experience often proves more complex. For instance, a patient with some usual comorbidities and non-obstructive mechanical valve thrombosis, experiencing symptoms solely by repeated systemic embolizations, might undergo all three therapeutic options due to the unpredictable nature of MVT. Therefore, treatment indications can intersect both on the time axis and depending on the patient's clinical status and the expertise of the center where he is hospitalized. Moreover, the European and American guidelines show subtle but important differences. The aim of this review was to compare these differences, comment on recent studies and evidence gaps, propose a more pragmatic algorithm combining all current recommendations, and highlight important research directions for this disease that has dominated the cardiovascular landscape for more than five decades, but for which there have been no significant recent changes in management.

Comparison of oral anticoagulants for stroke prevention in atrial fibrillation using the UK clinical practice research Datalink Aurum: A reference trial (ARISTOTLE) emulation study

BACKGROUND

Stroke prevention guidance for patients with atrial fibrillation (AF) uses evidence generated from randomised controlled trials (RCTs). However, applicability to patient groups excluded from trials remains unknown. Real-world patient data provide an opportunity to evaluate outcomes in a trial analogous population of direct oral anticoagulants (DOACs) users and in patients otherwise excluded from RCTs; however, there remains uncertainty on the validity of methods and suitability of the data. Successful reference trial emulation can support the generation of evidence around treatment effects in groups excluded or underrepresented in trials. We used linked United Kingdom primary care data to investigate whether we could emulate the pivotal ARISTOTLE trial (apixaban versus warfarin) and extend the analysis to investigate the impact of warfarin time in therapeutic range (TTR) on results.

METHODS AND FINDINGS

Patients with AF in the UK Clinical Practice Research Datalink (CPRD Aurum) prescribed apixaban or warfarin from 1 January 2013 to 31 July 2019 were selected. ARISTOTLE eligibility criteria were applied to this population and matched to the RCT apixaban arm on baseline characteristics creating a trial-analogous apixaban cohort; this was propensity-score matched to warfarin users in the CPRD Aurum. ARISTOTLE outcomes were assessed using Cox proportional hazards regression stratified by prior warfarin exposure status during 2.5 years of patient follow-up and results benchmarked against the trial results before treatment effectiveness was further evaluated based on (warfarin) TTR. The dataset comprised 8,734 apixaban users and propensity-score matched 8,734 warfarin users. Results [hazard ratio (95% confidence interval)] confirmed apixaban noninferiority for stroke or systemic embolism (SE) [CPRD 0.98 (0.82,1.19) versus trial 0.79 (0.66,0.95)] and death from any cause [CPRD 1.03 (0.93,1.14) versus trial 0.89 (0.80,0.998)] but did not indicate apixaban superiority. Absolute event rates for stroke/SE were similar for apixaban in CPRD Aurum and ARISTOTLE (1.27%/year), whereas a lower event rate was observed for warfarin (CPRD Aurum 1.29%/year, ARISTOTLE 1.60%/year). Analysis by TTR suggested similar effectiveness of apixaban compared with poorly controlled warfarin (TTR < 0.75) for stroke/SE [0.91 (0.73, 1.14)], all-cause death [0.94 (0.84, 1.06)], and superiority for major bleeding [0.74 (0.63, 0.86)]. However, when compared with well-controlled warfarin (TTR ≥ 0.75), apixaban was associated with an increased hazard for all-cause death [1.20 (1.04, 1.37)], and there was no significant benefit for major bleeding [1.08 (0.90, 1.30)]. The main limitation of the study's methodology are the risk of residual confounding, channelling bias and attrition bias in the warfarin arm, and selection bias and misclassification in the analysis by TTR.

CONCLUSIONS

Analysis of noninterventional data generated results demonstrating noninferiority of apixaban versus warfarin consistent with prespecified benchmarking criteria. Unlike in ARISTOTLE, superiority of apixaban versus warfarin was not seen, possible due to the lower proportion of Asian patients and higher proportion of patients with well-controlled warfarin compared to ARISTOTLE. This methodological template can be used to investigate treatment effects of oral anticoagulants in patient groups excluded from or underrepresented in trials and provides a framework that can be adapted to investigate treatment effects for other conditions.

Optimizing antithrombotic therapy in patients with coexisting cardiovascular and gastrointestinal disease

Balancing the safety and efficacy of antithrombotic agents in patients with gastrointestinal disorders is challenging because of the potential for interference with the absorption of antithrombotic drugs and for an increased risk of bleeding. In this Review, we address considerations for enteral antithrombotic therapy in patients with cardiovascular disease and gastrointestinal comorbidities. For those with gastrointestinal bleeding (GIB), we summarize a general scheme for risk stratification and clinical evidence on risk reduction approaches, such as limiting the use of concomitant medications that increase the risk of GIB and the potential utility of gastrointestinal protection strategies (such as proton pump inhibitors or histamine type 2 receptor antagonists). Furthermore, we summarize the best available evidence and potential gaps in our knowledge on tailoring antithrombotic therapy in patients with active or recent GIB and in those at high risk of GIB but without active or recent GIB. Finally, we review the recommendations provided by major medical societies, highlighting the crucial role of teamwork and multidisciplinary discussions to customize the antithrombotic regimen in patients with coexisting cardiovascular and gastrointestinal diseases.

Risk of bleeding with concomitant use of oral anticoagulants and aspirin: A systematic review and meta-analysis

PURPOSE

Oral anticoagulants (OACs) and aspirin can trigger bleeding events when used alone or in combination. The purpose of this study was to compare the risk of any type of bleeding in individuals exposed to a combination of OAC and aspirin with the risk in those taking an OAC or aspirin alone.

METHODS

MEDLINE and Web of Science were queried in January 2021 for eligible articles. Studies were included if they were either randomized controlled trials (RCTs) or observational studies and evaluated the number of any bleeding events in two groups, one with exposure to both OAC and aspirin and one with exposure to OAC alone or aspirin alone. Pooled odds ratios were calculated using a random-effects model.

RESULTS

Forty-two studies were included. In an analysis of 15 RCTs and 19 observational studies evaluating OAC plus aspirin versus OAC alone, a significant difference in the risk of bleeding was observed in the combination groups, with an odds ratio [OR] of, 1.36 (95% CI, 1.15-1.59) for RCTs and an OR of 1.42 (95% CI-, 1.09-1.87) for observational studies. When OAC plus aspirin was compared to aspirin alone, a higher rate of bleeding was found in the combination group (OR, 2.36; 95%CI, 1.91-2.92) in the analysis of 15 RCTs, but no significant difference was found among 10 observational studies (OR, 1.93; 95% Cl, 0.99-3.75).

CONCLUSION

The risk of any type of bleeding was significantly increased among patients taking aspirin plus OAC compared to those taking OAC alone in both RCTs and observational studies. Evaluation of RCTs comparing OAC plus aspirin to aspirin alone suggests increased bleeding risk as well.

How I treat the co-occurrence of venous and arterial thromboembolism: anticoagulation, antiplatelet therapy, or both?

ABSTRACT

Arterial and venous thromboses are classically considered distinct disease states, with arterial thrombosis mediated predominantly by platelets and therefore, treated with antiplatelet therapy, and venous thrombosis mediated by the plasmatic coagulation system and treated with anticoagulation. However, co-occurrence of arterial and venous events is common, and there is increasing evidence of shared risk factors and pathophysiologic overlap. This presents a management challenge: does the patient with venous and arterial thrombosis, require anticoagulation, antiplatelet therapy, or both? Herein, we present a structured approach to the evaluation and management of patients with venous thrombosis who are also at risk for or have a history of an arterial thromboembolic event. We emphasize the importance of defining the indications for antithrombotic therapy, as well as the evaluation of factors that influence both thrombotic and bleeding risk, including disorder-specific and patient-specific factors, as well as the inherent risk balance of antithrombotic therapy regimens. We illustrate this approach in 4 cases, discussing the unique considerations and recent updates in the management of venous thrombosis, acute noncardioembolic ischemic stroke, coronary artery disease and acute myocardial infarction, and peripheral artery disease after revascularization.

Outcomes of direct oral anticoagulants with aspirin vs warfarin with aspirin: a registry-based cohort study

Background

For patients anticoagulated with direct oral anticoagulants (DOACs) or warfarin and on aspirin (ASA) for nonvalvular atrial fibrillation and/or venous thromboembolism, it is unclear if bleeding outcomes differ.

Objectives

To assess bleeding rates for ASA with DOACs vs warfarin and one another.

Methods

Registry-based cohort study of patients followed by a 6-center quality improvement collaborative in Michigan using data from 2009 to 2022. The study included adults on ASA with warfarin or DOACs for atrial fibrillation and/or venous thromboembolism without a recent myocardial infarction or heart valve replacement.

Results

After propensity matching by anticoagulant class, we compared 2 groups of 1467 patients followed for a median of 18.0 months. Any bleeding and nonmajor bleeding was increased with DOACs + ASA compared with warfarin + ASA (32.2 vs 27.8 and 27.1 vs 22.9 events/100 patient-years; relative risks [RRs], 1.1 and 1.2; 95% CIs, 1.1-1.2 and 1.1-1.3, respectively). After matching by drug, patients on apixaban + ASA vs warfarin + ASA had more bleeding (31.2 vs 27.8 events/100 patient-years; RR, 1.1; 95% CI, 1.0-1.2) and nonmajor bleeding but less major bleeding (3.8 vs 4.7 events/100 patient-years; RR, 0.8; 95% CI, 0.6-1.0) and emergency room visits for bleeding. Patients on rivaroxaban + ASA vs warfarin + ASA had more bleeding (39.3 vs 26.3 events/100 patient-years, RR, 1.5; 95% CI, 1.3-1.6), nonmajor bleeding, and thrombosis. Patients on apixaban + ASA vs rivaroxaban + ASA had significantly less bleeding (22.5 vs 39.3/100 patient-years; RR, 0.6; 95% CI, 0.5-0.7), nonmajor bleeding, major bleeding (2.1 vs 5.5 events/100 patient-years; RR, 0.4; 95% CI, 0.2-0.6), emergency room visits for bleeding, and thrombotic events.

Conclusion

Patients on DOAC + ASA without a recent myocardial infarction or heart valve replacement had more nonmajor bleeding but otherwise similar outcomes compared with warfarin + ASA. Patients treated with rivaroxaban + ASA experienced more adverse clinical events compared with warfarin + ASA or apixaban + ASA.

Feasibility and acceptability of patient- and clinician-level antithrombotic stewardship interventions to reduce gastrointestinal bleeding risk in patients using warfarin (Anticoagulation with Enhanced Gastrointestinal Safety): a factorial randomized controlled pilot trial

Background

Overuse of antiplatelet therapy and underuse of gastroprotection contribute to preventable bleeding in patients taking anticoagulants.

Objectives

(1) Determine the feasibility of a factorial trial testing patient activation and clinician outreach to reduce gastrointestinal (GI) bleeding risk in patients prescribed warfarin-antiplatelet therapy without proton pump inhibitor gastroprotection and (2) assess intervention acceptability.

Methods

Pragmatic 2 × 2 factorial cluster-randomized controlled pilot comparing (1) a patient activation booklet vs usual care and (2) clinician notification vs clinician notification plus nurse facilitation was performed. The primary feasibility outcome was percentage of patients completing a structured telephone assessment after 5 weeks. Exploratory outcomes, including effectiveness, were evaluated using chart review, surveys, and semistructured interviews.

Results

Among 47 eligible patients, 35/47 (74.5%; 95% CI, 58.6%-85.7%) met the feasibility outcome. In the subset confirmed to be high risk for upper GI bleeding, 11/29 (37.9%; 95% CI, 16.9%-64.7%) made a medication change, without differences between intervention arms. In interviews, few patients reported reviewing the activation booklet; barriers included underestimating GI bleeding risk, misunderstanding the booklet's purpose, and receiving excessive health communication materials. Clinicians responded to notification messages for 24/47 patients (51.1%; 95% CI, 26.4%-75.4%), which was lower for surgeons than nonsurgeons (22.7% vs 76.0%). Medical specialists but not surgeons viewed clinician notification as acceptable.

Conclusion

The proposed trial design and outcome ascertainment strategy were feasible, but the patient activation intervention is unlikely to be effective as designed. While clinician notification appears promising, it may not be acceptable to surgeons, findings which support further refinement and testing of a clinician notification intervention.

Bleeding related to oral anticoagulants: Trends in US emergency department visits, 2016-2020

BACKGROUND

Clinical trials suggest lower rates of major bleeding with direct-acting oral anticoagulants (DOACs) than with warfarin, but anticoagulant-related bleeding remains one of the most common outpatient adverse drug events.

METHODS

We estimated the number of emergency department (ED) visits and subsequent hospitalizations for oral anticoagulant-related bleeding in 2016-2020 based on active surveillance in a nationally representative, size-stratified probability sample of 60 U.S. hospitals. We estimated rates of ED visits using a nationally-projected retail prescription dispensing database.

RESULTS

Based on 19,557 cases, oral anticoagulant-related bleeding resulted in an estimated 1,270,259 (95 % Confidence Interval [CI], 644,686-1,895,832) ED visits for the five years 2016-2020, of which 47.8 % (95 % CI, 40.6 %-55.0 %) resulted in hospitalization. Oral anticoagulant-related bleeding resulted in an estimated 230,163 (95% CI, 109,598-350,728) ED visits in 2016 and 301,433 (95% CI, 138,363-464,503) in 2020. During 2016-2020, ED visits for DOAC-related bleeding increased by an average of 27.9 % (95 % CI, 24.0 %-32.0 %; p < .001) per year, while ED visits for warfarin-related bleeding decreased by an average of 8.8 % (95 % CI, -10.7 % to -7.0 %; p = .001) per year. The estimated rate of bleeding visits per 100 patients dispensed oral anticoagulants at least once in 2016-2020 was highest for patients aged ≥ 80 years (13.1; 95 % CI, 6.2-20.0) and lowest for those aged <45 years (4.0; 95 % CI, 2.6-5.5); it was 5.9 visits per 100 patients dispensed DOACs [95 % CI, 2.5-9.2] and 13.0 visits per 100 patients dispensed warfarin [95 % CI, 7.4-18.7].

CONCLUSIONS

Although the rates of ED visits for anticoagulant-related bleeding may be lower for DOACs than for warfarin, persistently large numbers of patients requiring ED visits for anticoagulant-related bleeding despite increased use of DOACs and declining use of warfarin suggest that efforts to improve appropriate prescribing and monitoring of anticoagulants remain important.

Implementation of a Patient Questionnaire in Community Pharmacies to Improve Care for Patients Using Combined Antithrombotic Therapy: A Qualitative Study

For several indications or combinations of indications the use of more than one antithrombotic agent is required. The duration of combined antithrombotic therapy depends on indication and patient characteristics. This study investigated the use of an antithrombotic questionnaire tool that had been developed for pharmacists to detect patients with possible incorrect combined antithrombotic therapy. The objective of this study was to identify potential barriers and facilitators that could influence the implementation of the developed antithrombotic questionnaire tool in daily community pharmacy practice. A qualitative study was conducted at 10 Dutch community pharmacies in which the antithrombotic questionnaire tool had been used with 82 patients. Semi-structured interviews were conducted with pharmacy staff who used the antithrombotic questionnaire tool. The interview questions to identify barriers and facilitators were based on the Consolidated Framework for Implementation Research. The interview data were analysed using a deductive thematic analysis. Ten staff members from nine different pharmacies were interviewed. Facilitators for implementation were that the questionnaire was easily adaptable and easy to use, as well as the relative short duration to administer the questionnaire. A possible barrier for using the questionnaire was a lower priority for using the questionnaire at moments when the workload was high. The pharmacists estimated that the questionnaire could be used for 70-80% of the patient population and they thought that it was a useful addition to regular medication surveillance. The antithrombotic questionnaire tool can be easily implemented in pharmacy practice. To implement the tool, the focus should be on integrating its use into daily activities. Pharmacists can use this tool in addition to regular medication surveillance to improve medication safety in patients who use combined antithrombotic therapy.

Inappropriate Combined Antiplatelet and Anticoagulant Therapy in Older Patients with Atrial Fibrillation: Trend over Time (2009-18)

BACKGROUND AND OBJECTIVES

Antiplatelet therapy, when prescribed in combination with anticoagulant therapy to older patients with atrial fibrillation and no recent cardiovascular event, is inappropriate and a reversible risk factor of major bleeding. We aimed to assess the trend over time of the prevalence of inappropriate combined antiplatelet and anticoagulant therapy and to determine its associated factors during the direct oral anticoagulant era.

METHODS

This was a study of consecutive older patients (age ≥ 75 years) with atrial fibrillation, receiving anticoagulant therapy upon admission, and undergoing a comprehensive geriatric assessment during their first admission in a Belgian teaching hospital between 2009 and 2018. Antiplatelet therapy was considered inappropriate in the absence of a recent cardiovascular event. We studied the prevalence of inappropriate combined antiplatelet and anticoagulant therapy by 2-year periods and assessed its associated factors since the year 2013.

RESULTS

Inappropriate combined antiplatelet and anticoagulant therapy was identified in 21% of the 654 patients (median age 84 years, 51% women), with a prevalence decreasing (p ≤ 0.01) from 25% (2009-10) to 14.8% (2017-18). Among the 469 patients recruited during the direct oral anticoagulant era, inappropriate combined antiplatelet and anticoagulant therapy (19%) was associated in a multivariable analysis with a history of stroke/transient ischemic attack (odds ratio 2.13, p = 0.007), anticoagulation with low-molecular-weight heparin (odds ratio 3.44, p = 0.015), and a history of vascular disease (odds ratio 5.68, p < 0.001).

CONCLUSIONS

While inappropriate combined antiplatelet and anticoagulant therapy has declined over the last decade, there is still room for improvement. Antiplatelet deprescribing should be considered in all patients with inappropriate combined antiplatelet and anticoagulant therapy, including those with vascular disease and no recent cardiovascular event.

Severity and Hospitalization Cost Related to Warfarin-Related Adverse Events in a Tertiary Malaysian Hospital

Introduction: Oral anticoagulant is essential for the treatment and prevention of thromboembolism. Warfarin is an effective oral anticoagulant in prevention and treatment of thromboembolism. However, warfarin is frequently associated with adverse event (AE) requiring hospitalization. Method: We performed a retrospective cohort study of all patients admitted to a large tertiary public hospital for warfarin-related AEs. Patients were grouped based on bleeding severity and the direct medical cost was also calculated. Results: During the 4 years study period, a total of 224 patients were admitted for warfarin-related AEs. Mean age of patients admitted was 65.1 years (standard deviation [SD] = 11.5). More than half, 59.6%, of them were on warfarin for prevention of stroke in atrial fibrillation or atrial flutter. Major bleeding occurred among 50.9% of the patients with gastrointestinal bleed, 34 (29.8%), as the common site of bleed. Patients with major bleed had longer median hospital stay of 4 days (interquartile range [IQR] = 5) compared to 3 (IQR = 3) days in non-major bleed. There were 17 (14.9%) death among the major bleeders. Mean medical cost for managing warfarin-related AEs was USD 708.08. Conclusion: The admitted patients were equally distributed in terms of bleeding severity. Medical cost incurred for managing warfarin-related AEs increased with the severity of bleeding.

Assessment of an Intervention to Reduce Aspirin Prescribing for Patients Receiving Warfarin for Anticoagulation

IMPORTANCE

For some patients receiving warfarin, adding aspirin (acetylsalicylic acid) increases bleeding risk with unclear treatment benefit. Reducing excess aspirin use could be associated with improved clinical outcomes.

OBJECTIVE

To assess changes in aspirin use, bleeding, and thrombosis event rates among patients treated with warfarin.

DESIGN, SETTING, AND PARTICIPANTS

This pre-post observational quality improvement study was conducted from January 1, 2010, to December 31, 2019, at a 6-center quality improvement collaborative in Michigan among 6738 adults taking warfarin for atrial fibrillation and/or venous thromboembolism without an apparent indication for concomitant aspirin. Statistical analysis was conducted from November 26, 2020, to June 14, 2021.

INTERVENTION

Primary care professionals for patients taking aspirin were asked whether an ongoing combination aspirin and warfarin treatment was indicated. If not, then aspirin was discontinued with the approval of the managing clinician.

MAIN OUTCOMES AND MEASURES

Outcomes were assessed before and after intervention for the primary analysis and before and after 24 months before the intervention (when rates of aspirin use first began to decrease) for the secondary analysis. Outcomes included the rate of aspirin use, bleeding, and thrombotic outcomes. An interrupted time series analysis assessed cumulative monthly event rates over time.

RESULTS

A total of 6738 patients treated with warfarin (3160 men [46.9%]; mean [SD] age, 62.8 [16.2] years) were followed up for a median of 6.7 months (IQR, 3.2-19.3 months). Aspirin use decreased slightly from a baseline mean use of 29.4% (95% CI, 28.9%-29.9%) to 27.1% (95% CI, 26.1%-28.0%) during the 24 months before the intervention (P < .001 for slope before and after 24 months before the intervention) with an accelerated decrease after the intervention (mean aspirin use, 15.7%; 95% CI, 14.8%-16.8%; P = .001 for slope before and after intervention). In the primary analysis, the intervention was associated with a significant decrease in major bleeding events per month (preintervention, 0.31%; 95% CI, 0.27%-0.34%; postintervention, 0.21%; 95% CI, 0.14%-0.28%; P = .03 for difference in slope before and after intervention). No change was observed in mean percentage of patients having a thrombotic event from before to after the intervention (0.21% vs 0.24%; P = .34 for difference in slope). In the secondary analysis, reducing aspirin use (starting 24 months before the intervention) was associated with decreases in mean percentage of patients having any bleeding event (2.3% vs 1.5%; P = .02 for change in slope before and after 24 months before the intervention), mean percentage of patients having a major bleeding event (0.31% vs 0.25%; P = .001 for change in slope before and after 24 months before the intervention), and mean percentage of patients with an emergency department visit for bleeding (0.99% vs 0.67%; P = .04 for change in slope before and after 24 months before the intervention), with no change in mean percentage of patients with a thrombotic event (0.20% vs 0.23%; P = .36 for change in slope before and after 24 months before the intervention).

CONCLUSIONS AND RELEVANCE

This quality improvement intervention was associated with an acceleration of a preexisting decrease in aspirin use among patients taking warfarin for atrial fibrillation and/or venous thromboembolism without a clear indication for aspirin therapy. Reductions in aspirin use were associated with reduced bleeding. This study suggests that an anticoagulation clinic-based aspirin deimplementation intervention can improve guideline-concordant aspirin use.

Comparing Important and Well-documented Potential Drug–Drug Interactions between Emergency, Medical, and Surgical ICUs of a Respiratory Referral Center

Introduction

Drug–drug interaction (DDI) is one of the major healthcare challenges in intensive care units (ICUs). The prevalence of DDIs and interacting drug pairs may vary between different types of ICUs. This study aimed to compare the frequency and nature of important and well-documented potential DDIs (pDDIs) in three types of ICUs.

Materials and methods

A prospective study was conducted in medical (M), surgical (S), and emergency (E) ICUs of a tertiary referral center for respiratory diseases. A pharmacist checked the patients’ files three days in a week for 6 months. The pDDIs were identified using the Lexi-Interact database. Interactions with a severity rating of D (modify regimen) and X (avoid combination) and with a reliability rating of good and excellent were considered important and well-documented. These pDDIs were evaluated in terms of drug combinations, mechanisms of interaction, and clinical management.

Results

One hundred eighty-nine patients admitted to MICU, SICU, and EICU were included in the study. The percentage of patients who experienced at least one important and well-documented pDDI was 18.8% in MICU, 11.1% in SICU, and 11.8% in EICU. The most common drug pairs causing important and well-documented interactions were atracurium + hydrocortisone in MICU, meropenem + valproic acid in MICU and EICU, and aspirin + warfarin in SICU.

Conclusion

The current study shows different frequency and nature of pDDIs between three types of ICUs. We recommend conducting similar studies in other settings to develop evidence-based guidance on clinically relevant pDDIs in different types of ICUs.

How to cite this article

Hosseinpoor Z, Farzanegan B, Baniasadi S. Comparing Important and Well-documented Potential Drug–Drug Interactions between Emergency, Medical, and Surgical ICUs of a Respiratory Referral Center. Indian J Crit Care Med 2022;26(5):574–578.

Bleeding Complications Associated With Intrauterine Contraception in Women Receiving Anticoagulation Therapy

Objective

Patients and Methods

Results

Conclusion

A randomized non-inferiority study of low-dose and standard-dose ticagrelor after intervention for acute coronary syndrome: study protocol for the TIGER STUDY

Background

Current guidelines recommend that patients with acute coronary syndrome (ACS) who have successfully undergone percutaneous coronary intervention (PCI) should continue to use dual antiplatelet therapy (DAPT) for 12 months. The long-term use of standard-dose dual antiplatelet therapy will increase the risk of bleeding. An optimized antiplatelet strategy that can prevent ischemic events and reduce the risk of bleeding remains to be explored.

Methods

The study is a prospective, multicenter, randomized, open-label, controlled study involving 2090 patients from six clinical centers in China. Through the interactive web response system (IWRS), ACS patients undergoing successful PCI will be randomly divided into the low-dose ticagrelor group or the normal-dose ticagrelor group, after taking 100 mg aspirin and 90 mg ticagrelor bid for 1 week. The primary endpoint is a composite of cardiovascular death, non-fatal myocardial infarction, stent thrombosis, repeat revascularization, and stroke. The secondary endpoints are bleeding events of grade 2 or higher according to Bleeding Academic Research Consortium [BARC] criteria, cardiovascular death, acute myocardium infarction, and coronary revascularization at 1 year.

Discussion

Recent studies have confirmed that 90 mg ticagrelor alone can safely and effectively reduce bleeding without increasing ischemic events of patients with ACS after PCI. Compared with standard-dose DAPT, whether low-dose ticagrelor combined with aspirin can ensure the anti-ischemic effect while reducing the bleeding risk remains unclear in Chinese patients.

The TIGER study will be the first large-scale, multicenter study to compare the efficacy and safety of low-dose and standard-dose ticagrelor combined with aspirin in ACS patients 1 week after successful PCI.

Trial registration

Clinicaltrials.gov NCT04255602. Registered on 5 February 2020.

Development of a multicomponent implementation strategy to reduce upper gastrointestinal bleeding risk in patients using warfarin and antiplatelet therapy, and protocol for a pragmatic multilevel randomized factorial pilot implementation trial

BACKGROUND

The concomitant use of anticoagulant and antiplatelet medications increases the risk of upper gastrointestinal (GI) bleeding. Two underused evidence-based practices (EBPs) can reduce the risk: de-prescribe unnecessary antiplatelet therapy or initiate a proton pump inhibitor. We describe the development of a multicomponent intervention to increase use of these EBPs in patients treated with warfarin and followed by an anticoagulation monitoring service (AMS), and the design of a pilot pragmatic implementation trial.

METHODS

A participatory planning group iteratively used Implementation Mapping and the Multiphase Optimization Strategy to develop implementation strategies and plan the trial. Informed by qualitative interviews with patients and clinicians, we drew on several implementation science theories, as well as self-determination theory, to design interventions. For patients, we developed an activation guide to help patients discuss the EBPs with their clinicians. For clinicians, we developed two electronic health record (EHR)-based interventions: (1) clinician notification (CN) consists of a templated message that identifies a patient as high risk, summarizes the EBPs, and links to a guidance statement on appropriate use of antiplatelet therapy. (2) Clinician notification with nurse facilitation (CN+NF) consists of a similar notification message but includes additional measures by nursing staff to support appropriate and timely decision-making: the nurse performs a chart review to identify any history of vascular disease, embeds indication-specific guidance on antiplatelet therapy in the message, and offers to assist with medication order entry and patient education. We will conduct a pilot factorial cluster- and individual-level randomized controlled trial with a primary objective of evaluating feasibility. Twelve clinicians will be randomized to receive either CN or CN+NF for all their patients managed by the AMS while 50 patients will be individually randomized to receive either the activation guide or usual care. We will explore implementation outcomes using patient and clinician interviews along with EHR review.

DISCUSSION

This pilot study will prepare us to conduct a larger optimization study to identify the most potent and resource conscious multicomponent implementation strategy to help AMSs increase the use of best practices for upper GI bleeding risk reduction.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05085405 . Registered on October 19, 2021-retrospectively registered.

Management of acute venous thromboembolism in patients taking antiplatelet therapy

BACKGROUND

Concomitant anticoagulant and antiplatelet therapy increases bleeding risk, but most data are derived from patients with atrial fibrillation. Patients with venous thromboembolism (VTE) may differ.

OBJECTIVE

To study the management of patients diagnosed with acute VTE while receiving antiplatelet treatment. The primary outcome was the number of patients discharged with concomitant therapy. Secondary outcomes were clinically relevant bleeding, cardiovascular events, recurrent VTE and death during follow-up, according to discharge therapy.

METHODS

We performed a post-hoc analysis of patients included in two prospective registries, sharing the same case report form, from 2007 to 2017.

RESULTS

Among the 1694 identified patients, 254 (15.0%) were receiving antiplatelet treatment at VTE diagnosis, of whom 61 (24.0%) were discharged with concomitant anticoagulant and antiplatelet therapy. In multivariable analysis, age ≥ 80 years-old and the use of Direct Oral Anticoagulants for VTE therapy were associated with the decision to stop the antiplatelet, while having dual anti-platelet therapy at baseline, a history of coronaropathy or peripheral arterial disease were associated with concomitant anticoagulant and antiplatelet therapy. The decision to stop antiplatelet was associated with a non-significant 46% decrease in the risk of bleeding (OR 0.54 (0.16; 1.78)), and a non-significant 68% increase in the risk of cardiovascular events (OR 1.68 (0.44; 6.46)).

CONCLUSION

At acute VTE diagnosis, over 15% of patients were receiving antiplatelet agents, of whom 24% were discharged with concomitant anticoagulant and antiplatelet therapy. This therapeutic decision may be associated with a lower risk of cardiovascular events, but an increased risk of bleeding.

Prevalence and Factors Associated with Potential Drug-Drug Interactions in Older Community-Dwelling Adults: A Prospective Cohort Study

BACKGROUND

Older patients are at increased risk of drug-drug interactions (DDIs) due to polypharmacy. Cardiovascular and central nervous system (CNS) drugs are commonly implicated in serious DDIs.

OBJECTIVES

This study aimed to determine the prevalence and factors associated with potential 'severe' cardiovascular and CNS DDIs among older (≥ 70 years) community-dwellers.

METHODS

This was a prospective cohort study using linked data from a national pharmacy claims database and waves 1 and 2 of The Irish LongituDinal study on Ageing (TILDA). 'Severe' cardiovascular and CNS DDIs were identified using the British National Formulary 77 and Stockley's Drug Interactions. The prevalence of 'severe' DDIs (any DDI vs. none) was calculated. Logistic regression was used to examine the association between sociodemographic, functional ability, and medication-related factors and the risk of DDI exposure between waves 1 and 2.

RESULTS

A total of 1466 patients were included [mean age (standard deviation) = 78 (5.5) years; female n = 795, 54.2%]. In total, 332 community-dwellers aged ≥ 70 years [22.65%, 95% confidence interval (CI) 20.58-24.86] were potentially exposed to at least one 'severe' cardiovascular or CNS DDI, with more than half (54.82%) of this cohort dispensed the same DDI for a prolonged time (≥ 3 consecutive claims). Aspirin-warfarin was the most frequently dispensed (co-prescribed) DDI (n = 34, 10.24%, 95% CI 7.39-14.00), followed by atorvastatin-clarithromycin (n = 19, 5.72%, 95% CI 3.64-8.81). Polypharmacy [≥ 10 vs. < 5 drugs, odds ratio (OR) 13.40, 95% CI 8.22-21.85] and depression (depressed vs. not, OR 2.12, 95% CI 1.34-3.34) were significantly associated with these DDIs, after multivariable adjustment.

CONCLUSION

'Severe' cardiovascular and CNS DDIs are prevalent in older community-dwellers in Ireland, and those with polypharmacy and depression are at a significantly increased risk.

Anticoagulant-associated gastrointestinal bleeding: Framework for decisions about whether, when and how to resume anticoagulants

Gastrointestinal (GI) bleeding is the most frequent single site of oral anticoagulant (OAC)-associated major bleeding. Patients with major GI bleeding experience morbidity and a substantial risk of short-term all-cause mortality up to 10%. While OACs are frequently discontinued during acute bleeding, there is substantial uncertainty about whether, when, and how OACs should be resumed after bleeding has resolved. Limited evidence suggests a lower risk of thromboembolism and death, and a higher risk of recurrent bleeding with OAC resumption. However, the absolute risks and optimal timing of anticoagulation remain uncertain based on these observational studies at risk of bias, particularly due to baseline confounding. In addition to an individualized approach to determining the benefits and harms of treatment decisions informed by the best available evidence about thrombosis and recurrent bleeding, discussions should meaningfully incorporate patient values and preferences. The objective of this review is to provide a framework for decision-making by summarizing the epidemiology and clinical outcomes of OAC-associated GI bleeding, providing an approach for assessment and risk stratification for OAC resumption and its timing, and outlining strategies for the prevention of recurrent GI bleeding.

New Internet-Based Warfarin Anticoagulation Management Approach After Mechanical Heart Valve Replacement: Prospective, Multicenter, Randomized Controlled Trial

BACKGROUND

Mechanical heart valve replacement (MHVR) is an effective method for the treatment of severe heart valve disease; however, it subjects patient to lifelong warfarin therapy after MHVR with the attendant risk of bleeding and thrombosis. Whether internet-based warfarin management reduces complications and improves patient quality of life remains unknown.

OBJECTIVE

This study aimed to compare the effects of internet-based warfarin management and the conventional approach in patients who received MHVR in order to provide evidence regarding alternative strategies for long-term anticoagulation.

METHODS

This was a prospective, multicenter, randomized, open-label, controlled clinical trial with a 1-year follow-up. Patients who needed long-term warfarin anticoagulation after MHVR were enrolled and then randomly divided into conventional and internet-based management groups. The percentage of time in the therapeutic range (TTR) was used as the primary outcome, while bleeding, thrombosis, and other events were the secondary outcomes.

RESULTS

A total of 721 patients were enrolled. The baseline characteristics did not reach statistical differences between the 2 groups, suggesting the random assignment was successful. As a result, the internet-based group showed a significantly higher TTR (mean 0.53, SD 0.24 vs mean 0.46, SD 0.21; P<.001) and fraction of time in the therapeutic range (mean 0.48, SD 0.22 vs mean 0.42, SD 0.19; P<.001) than did those in the conventional group. Furthermore, as expected, the anticoagulation complications, including the bleeding and embolic events had a lower frequency in the internet-based group than in the conventional group (6.94% vs 12.74%; P=.01). Logistic regression showed that internet-based management increased the TTR by 7% (odds ratio [OR] 1.07, 95% CI 1.05-1.09; P<.001) and reduced the bleeding and embolic risk by 6% (OR 0.94, 95% CI 0.92-0.96; P=.01). Moreover, low TTR was found to be a risk factor for bleeding and embolic events (OR 0.87, 95% CI 0.83-0.91; P=.005).

CONCLUSIONS

The internet-based warfarin management is superior to the conventional method, as it can reduce the anticoagulation complications in patients who receive long-term warfarin anticoagulation after MHVR.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR1800016204; http://www.chictr.org.cn/showproj.aspx?proj=27518.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1136/bmjopen-2019-032949.

Adverse Events Associated With the Addition of Aspirin to Direct Oral Anticoagulant Therapy Without a Clear Indication

IMPORTANCE

It is unclear how many patients treated with a direct oral anticoagulant (DOAC) are using concomitant acetylsalicylic acid (ASA, or aspirin) and how this affects clinical outcomes.

OBJECTIVE

To evaluate the frequency and outcomes of prescription of concomitant ASA and DOAC therapy for patients with atrial fibrillation (AF) or venous thromboembolic disease (VTE).

DESIGN, SETTING, AND PARTICIPANTS

This registry-based cohort study took place at 4 anticoagulation clinics in Michigan from January 2015 to December 2019. Eligible participants were adults undergoing treatment with a DOAC for AF or VTE, without a recent myocardial infarction (MI) or history of heart valve replacement, with at least 3 months of follow-up.

EXPOSURES

Use of ASA concomitant with DOAC therapy.

MAIN OUTCOMES AND MEASURES

Rates of bleeding (any, nonmajor, major), rates of thrombosis (stroke, VTE, MI), emergency department visits, hospitalizations, and death.

RESULTS

Of the study cohort of 3280 patients (1673 [51.0%] men; mean [SD] age 68.2 [13.3] years), 1107 (33.8%) patients without a clear indication for ASA were being treated with DOACs and ASA. Two propensity score-matched cohorts, each with 1047 patients, were analyzed (DOAC plus ASA and DOAC only). Patients were followed up for a mean (SD) of 20.9 (19.0) months. Patients taking DOAC and ASA experienced more bleeding events compared with DOAC monotherapy (26.0 bleeds vs 31.6 bleeds per 100 patient years, P = .01). Specifically, patients undergoing combination therapy had significantly higher rates of nonmajor bleeding (26.1 bleeds vs 21.7 bleeds per 100 patient years, P = .02) compared with DOAC monotherapy. Major bleeding rates were similar between the 2 cohorts. Thrombotic event rates were also similar between the cohorts (2.5 events vs 2.3 events per 100 patient years for patients treated with DOAC and ASA compared with DOAC monotherapy, P = .80). Patients were more often hospitalized while undergoing combination therapy (9.1 vs 6.5 admissions per 100 patient years, P = .02).

CONCLUSION AND RELEVANCE

Nearly one-third of patients with AF and/or VTE who were treated with a DOAC received ASA without a clear indication. Compared with DOAC monotherapy, concurrent DOAC and ASA use was associated with increased bleeding and hospitalizations but similar observed thrombosis rate. Future research should identify and deprescribe ASA for patients when the risk exceeds the anticipated benefit.

Impact of Preinjury Antithrombotic Therapy on 30-Day Mortality in Older Patients Hospitalized With Traumatic Brain Injury (TBI)

Objective: Elderly patients are frequently in need of antithrombotic therapy for reducing thrombotic events. The association between antithrombotic drugs and survival after traumatic brain injury (TBI) is, nevertheless, unclear.

Methods: This retrospective study included patients ≥65 years admitted to a Norwegian Level 1 trauma center with TBI identified on cerebral computed tomography (cerebral-CT) during 2014–2019. Preinjury use of antiplatelets and anticoagulants was compared to the prescription rate in the general Norwegian population. The primary outcome was 30-day mortality. Uni- and multivariate logistic regression analyses estimated the association between the use of antithrombotic drugs and mortality.

Results: The study includes 832 consecutive TBI patients ≥65 years. The median age was 76 years, 58% were males, 51% had moderate or severe TBI, and 39% had multiple traumas. Preinjury use of antithrombotics was registered in 471/832 (55.6%) patients; antiplatelet therapy alone in 268, anticoagulant therapy alone in 172, and combined antiplatelet and anticoagulant therapy in 31. Antiplatelet use did not differ between the study cohort and the general Norwegian population ≥65 years (31 vs. 31%, p = 0.87). Anticoagulant therapy was used more commonly in the study cohort than in the general Norwegian population (24 vs. 19%, p = 0.04). Combined use of antiplatelet and anticoagulant therapy was significantly associated with 30-day mortality, while preinjury antiplatelet or anticoagulation treatment alone was not. No difference in 30-day mortality between patients using VKA, DOACs, or LMWH was encountered.

Conclusions: In this cohort, neither antiplatelet nor anticoagulant therapy alone was associated with increased 30-day mortality. Anticoagulant use was more prevalent among TBI patients than the general population, suggesting that anticoagulation might contribute to the initiation of intracranial bleeding after blunt head trauma. Combined antiplatelet and anticoagulant therapy posed increased risk of 30-day mortality.

Drug-drug Interactions with Warfarin: A Systematic Review and Meta-analysis

AIM

The objective of this paper is to systematically review the literature on drug-drug interactions with warfarin, with a focus on patient-important clinical outcomes.

METHODS

MEDLINE, EMBASE, and the International Pharmaceutical Abstract (IPA) databases were searched from January 2004 to August 2019. We included studies describing drug-drug interactions between warfarin and other drugs. Screening and data extraction were conducted independently and in duplicate. We synthesized pooled odds ratios (OR) with 95% confidence intervals (CIs), comparing warfarin plus another medication to warfarin alone. We assessed the risk of bias at the study level and evaluated the overall certainty of evidence using GRADE.

RESULTS

Of 42,013 citations identified, a total of 72 studies reporting on 3,735,775 patients were considered eligible, including 11 randomized clinical trials and 61 observational studies. Increased risk of clinically relevant bleeding when added to warfarin therapy was observed for antiplatelet (AP) regimens (OR=1.74; 95% CI 1.56, 1.94), many antimicrobials (OR=1.63; 95% CI 1.45, 1.83), NSAIDs including COX-2 NSAIDs (OR=1.83; 95% CI 1.29, 2.59), SSRIs (OR=1.62; 95% CI 1.42, 1.85), mirtazapine (OR=1.75; 95% CI 1.30, 2.36), loop diuretics (OR=1.92; 95% CI 1.29, 2.86), and others. We found a protective effect of proton pump inhibitors (PPIs) against warfarin-related gastrointestinal (GI) bleedings (OR=0.69; 95% CI 0.64, 0.73). No significant effect on thromboembolic events or mortality of any drug group used with warfarin was found, including single or dual AP regimens.

CONCLUSIONS

This review found low to moderate certainty evidence supporting the interaction between warfarin and a small group of medications, which result in increased bleeding risk. PPIs are associated with reduced hospitalization for upper GI bleeding for patients taking warfarin. Further studies are required to better understand drug-drug interactions leading to thromboembolic outcomes or death.

How I treat unexplained arterial thrombosis

Most arterial thrombotic events have a clear atherosclerotic or cardioembolic etiology, but hematologists are frequently asked to assist in the diagnosis and management of a patient with a nonatherosclerotic and noncardioembolic arterial event, referred to here as an unexplained arterial thrombosis. Because there is an assorted list of factors that can precipitate an arterial event, we present a systematic diagnostic approach to ensure consideration of not only primary hypercoagulable disorders, but also pro-thrombotic medications or substances, vascular and anatomic abnormalities, and undiagnosed systemic disorders, such as malignancy and autoimmune diseases. We also review existing literature of the role of hypercoagulable disorders in arterial thrombosis and discuss our approach to thrombophilia workup in patients after an unexplained arterial event. We conclude with 3 representative cases to both illustrate the application of the outlined diagnostic schema and discuss common management considerations, specifically the selection of anticoagulation vs antiplatelet therapy for secondary prevention.

Percutaneous Occlusion of the Left Atrial Appendage with Thrombus Irresponsive to Antithrombotic Therapy

We analyzed clinical experience with percutaneous closure of instances of left atrial appendage with thrombus (LAAT) irresponsive to antithrombotic therapy in patients treated in three high-volume cardiology centers. Clinical and procedural data regarding consecutive patients who underwent percutaneous left atrial appendage closure (PLAAC) due to LAAT were retrospectively analyzed. The study population consisted of 17 patients (11 men; 68 ± 14 years; CHA₂DS₂VASC 4.7 ± 1.9; HASBLED 3 (0-5)) with LAAT confirmed by transesophageal echocardiography, and included 5 patients with mechanical heart valves. Most of the patients (94.1%) received anticoagulation therapy before PLAAC. All LAATs were located in distal portions of the appendage and occupied less than 30% of its volume. Occluding-device implantation was successful in 17 patients; in one, a residual leak was disclosed. Appropriate positioning of occluders required more than 1 attempt in 6 individuals (35.3%); in 3 others (17.6%), the subjects' devices had contact with thrombi. No procedural complications were noted. Midterm follow-up (median: 10 months) revealed no procedure-related complications or clinically diagnosed thromboembolism. Transesophageal echocardiography (TEE) performed after six months revealed device-related thrombus in one patient. We concluded that LAAT irresponsive to antithrombotic therapy might be effectively treated with PLAAC, even in patients with mechanical-valve prostheses.

Combining antiplatelet and anticoagulant therapy in cardiovascular disease

Up to 10% of the >3 million Americans with atrial fibrillation will experience an acute coronary syndrome or undergo percutaneous coronary intervention. Therefore, concurrent indications for multiple antithrombotic agents is a common clinical scenario. Although each helps reduce thrombotic risk, their combined use significantly increases the risk of major bleeding events, which can be life threatening. In the past 5 years, a number of randomized clinical trials have explored different combinations of anticoagulation plus antiplatelet agents aimed at minimizing bleeding risk while preserving low thrombotic event rates. In general, shorter courses with fewer antithrombotic agents have been found to be effective, particularly when direct oral anticoagulants are combined with clopidogrel. Combined use of very low-dose rivaroxaban plus aspirin has also demonstrated benefit in atherosclerotic diseases, including coronary and peripheral artery disease. Use of proton pump inhibitor therapy while patients are taking multiple antithrombotic agents has the potential to further reduce upper gastrointestinal bleeding risk in select populations. Applying this evidence to patients with multiple thrombotic conditions will help to avoid costly and life-threatening adverse medication events.

Impact of concomitant antiplatelet therapy on the efficacy and safety of direct oral anticoagulants for acute venous thromboembolism: Systematic review and meta-analysis

BACKGROUND

Direct oral anticoagulants (DOACs) are recommended over vitamin K antagonists (VKAs) for the treatment of venous thromboembolism (VTE). Concomitant antiplatelet therapy may potentiate the antithrombotic effects of DOACs.

OBJECTIVES

We evaluated the impact of concomitant antiplatelet therapy on the efficacy and safety of DOACs.

PATIENTS/METHODS

MEDLINE, EMBASE, and Clinicaltrial.gov were searched for randomized controlled trials of DOACs for the treatment of acute VTE. The efficacy outcome was symptomatic recurrent VTE and VTE-related death; the primary safety outcome was major bleeding.

RESULTS

Six randomized controlled trials included 26 924 patients of whom 3550 (13.2%) received concomitant antiplatelet therapy, mainly aspirin (67.7%). Concomitant antiplatelet therapy did not reduce the incidence of recurrent VTE and VTE-related death with any oral anticoagulant (odds ratio [OR] 1.17; 95% confidence interval [CI], 0.92-1.48), with DOACs (OR 1.21; 95% CI, 0.86-1.71), or VKAs alone (OR 1.16; 95% CI, 0.77-1.73). Compared with no antiplatelet therapy, concomitant antiplatelet therapy was associated with a higher risk of major bleeding in patients with any oral anticoagulant (OR 1.79; 95% CI, 1.22-2.63), DOACs (OR 1.89; 95% CI, 1.04-3.44), or VKAs (OR 1.73; 95% CI, 1.16-2.59). In patients receiving concomitant antiplatelet therapy, there were no statistically significant differences in efficacy or safety outcomes with DOACs or VKAs (OR 0.99; 95% CI, 0.64-1.51, and OR 0.68; 95% CI, 0.32-1.45, respectively).

CONCLUSIONS

Concomitant use of antiplatelet therapy with oral anticoagulants does not appear to affect the risk of recurrent VTE and increases the risk of major bleeding.

Risk Versus Benefit of Combined Aspirin and Warfarin Therapy in Patients With Atrial Fibrillation

PURPOSE

Guidelines have differing recommendations for aspirin use in patients with an indication for anticoagulation. The purpose of this study was to evaluate the incidence of major bleeding and thromboembolic events (TEs) in patients with atrial fibrillation (AF) receiving warfarin alone (monotherapy group) versus warfarin plus aspirin (combination therapy group).

METHODS

This was a retrospective, cohort study including patients from a pharmacist-run anticoagulation clinic. Inclusion criteria were patients with AF receiving anticoagulation between January 2013 and January 2014 observed over 5 years.

RESULTS

One hundred forty-two patients were included in the combination group versus 89 in monotherapy group. In the combination group, 60 (42.3%) patients were on aspirin for no apparent indication, 19 (13.4%) had stable coronary artery disease and diabetes, and 26 (18.3%) had diabetes alone. Major bleeding occurred in 21 (14.9%) patients in the combination group versus 7 (7.9%) patients in the monotherapy group (odds ratio [OR] = 2.02, 95% confidence interval [CI]: 0.78-5.91; P = .17). TE occurred in 10 (7%) patients in the combination group versus 4 (4.5%) in the monotherapy group (OR = 1.61, 95% CI: 0.44-7.24; P = .57). There was no significant difference in bleeding (P = .85) or TE (P = .37) rates between aspirin indications in the combination group.

CONCLUSION

Combination therapy versus monotherapy may increase bleeding risk with little benefit in decreasing AF-related stroke or cardiovascular events.

Direct oral anticoagulant plus antiplatelet therapy: prescribing practices and bleeding outcomes

Concurrent antiplatelet therapy (APT) is common during warfarin therapy but is less well-documented during direct oral anticoagulant (DOAC) therapy. Combined anticoagulant and APT use has been associated with increased bleeding risk without providing additional protection against thrombosis. This study aimed to describe single-center prescribing rates of DOAC + APT as well as compare bleeding rates between DOAC monotherapy and DOAC + APT cohorts. Patients receiving DOAC therapy were evaluated for APT use at the time of hospital discharge. Patients were categorized into DOAC monotherapy and DOAC + APT cohorts. Primary outcomes included DOAC + APT prescribing rate as well as rates of major bleeding and clinically relevant non-major bleeding (CRNMB) within six months after hospital discharge. Secondary outcomes included rates of thromboembolism and all-cause mortality. Of 407 patients receiving DOAC therapy, 78 (19.2%) also received APT at hospital discharge. Common indications for APT included secondary cardiovascular event prevention (57.7%) and primary cardiovascular event prevention (29.5%). The indication for APT could not be determined in 12.8% of patients. The major bleeding rate was 1.3% for DOAC + APT and 1.2% for DOAC monotherapy (p = 0.95). The CRNMB rate was 10.2% for DOAC + APT and 6.4% for DOAC monotherapy (p = 0.23). Thromboembolism and mortality were infrequent in both cohorts. DOAC + APT was documented in approximately 1 of 5 patients. Adding APT to DOAC therapy did not significantly increase the major bleeding or CRNMB rates compared to DOAC monotherapy but the sample size limits drawing conclusions about the safety of these regimens. Targeting primary prevention or unclear indications for APT could be a focus of future interventions.