Expanding the recognition and assessment of bleeding events associated with antiplatelet therapy in primary care

Reversing Bleeding Associated With Antiplatelet Use: The Role of Tranexamic Acid

Dual antiplatelet therapy (DAPT) is the mainstay of therapy in patients that have been diagnosed with coronary artery disease. DAPT has known risk factors such as an increased risk of bleeding, and, currently, no specific medication is indicated to reverse bleeding associated with antiplatelet use. One medication that may help reduce blood loss is tranexamic acid (TXA). A retrospective review of the literature regarding TXA in the setting of antiplatelet associated bleeding through a systematic search strategy was conducted. This review of the literature followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines and included seven studies. Multiple studies demonstrated the impact on platelet function resulting from administering TXA through lower volumes of blood loss, lower transfusion requirements, and lower incidence of reoperations. TXA is not widely recommended to reverse antiplatelet medications; however, it is widely available, has a positive track record for use in various types of bleeding, and is relatively inexpensive and safe. Large-scale randomized trials are warranted to make a strong recommendation for TXA in reversing bleeding associated with antiplatelet therapy.

Progress toward a Glycoprotein VI Modulator for the Treatment of Thrombosis

Pathogenic thrombus formation accounts for the etiology of many serious conditions including myocardial infarction, stroke, deep vein thrombosis, and pulmonary embolism. Despite the development of numerous anticoagulants and antiplatelet agents, the mortality rate associated with these diseases remains high. In recent years, however, significant epidemiological evidence and clinical models have emerged to suggest that modulation of the glycoprotein VI (GPVI) platelet receptor could be harnessed as a novel antiplatelet strategy. As such, many peptidic agents have been described in the past decade, while more recent efforts have focused on the development of small molecule modulators. Herein the rationale for targeting GPVI is summarized and the published GPVI modulators are reviewed, with particular focus on small molecules. A qualitative pharmacophore hypothesis for small molecule ligands at GPVI is also presented.

Comprehensive ascertainment of bleeding in patients prescribed different combinations of dual antiplatelet therapy (DAPT) and triple therapy (TT) in the UK: study protocol for three population-based cohort studies emulating 'target trials' (the ADAPTT Study)

INTRODUCTION

'Real world' bleeding in patients exposed to different regimens of dual antiplatelet therapy (DAPT) and triple therapy (TT, DAPT plus an anticoagulant) have a clinical and economic impact but have not been previously quantified.

METHODS AND ANALYSIS

We will use linked Clinical Practice Research Datalink (CPRD) and Hospital Episode Statistics (HES) data to assemble populations eligible for three 'target trials' in patient groups: percutaneous coronary intervention (PCI); coronary artery bypass grafting (CABG); conservatively managed (medication only) acute coronary syndrome (ACS). Patients ≥18 years old will be eligible if, in CPRD records, they have: ≥1 year of data before the index event; no prescription for DAPT or anticoagulants in the preceding 3 months; a prescription for aspirin or DAPT within 2 months after discharge from the index event. The primary outcome will be any bleeding event (CPRD or HES) up to 12 months after the index event. We will estimate adjusted HR for time to first bleeding event comparing: aspirin and clopidogrel (reference) versus aspirin and prasugrel or aspirin and ticagrelor after PCI; and aspirin (reference) versus aspirin and clopidogrel after CABG and ACS. We will describe rates of bleeding in patients prescribed TT (DAPT plus an anticoagulant). Potential confounders will be identified systematically using literature review, semistructured interviews with clinicians and a short survey of clinicians. We will conduct sensitivity analyses addressing the robustness of results to the study's main limitation-that we will not be able to identify the intervention group for patients whose bleeding event occurs before a DAPT prescription in CPRD.

ETHICS AND DISSEMINATION

This protocol was approved by the Independent Scientific Advisory Committee for the UK Medicines and Healthcare Products Regulatory Agency Database Research (protocol 16_126R) and the South West Cornwall and Plymouth Research Ethics Committee (17/SW/0092). The findings will be presented in peer-reviewed journals, lay summaries and briefing papers to commissioners/other stakeholders.

TRIAL REGISTRATION NUMBER

76607611; Pre-results.

Development of a gut microbe-targeted nonlethal therapeutic to inhibit thrombosis potential

Trimethylamine N-oxide (TMAO) is a gut microbiota-derived metabolite that enhances both platelet responsiveness and in vivo thrombosis potential in animal models, and TMAO plasma levels predict incident atherothrombotic event risks in human clinical studies. TMAO is formed by gut microbe-dependent metabolism of trimethylamine (TMA) moiety-containing nutrients, which are abundant in a Western diet. Here, using a mechanism-based inhibitor approach targeting a major microbial TMA-generating enzyme pair, CutC and CutD (CutC/D), we developed inhibitors that are potent, time-dependent, and irreversible and that do not affect commensal viability. In animal models, a single oral dose of a CutC/D inhibitor significantly reduced plasma TMAO levels for up to 3 d and rescued diet-induced enhanced platelet responsiveness and thrombus formation, without observable toxicity or increased bleeding risk. The inhibitor selectively accumulated within intestinal microbes to millimolar levels, a concentration over 1-million-fold higher than needed for a therapeutic effect. These studies reveal that mechanism-based inhibition of gut microbial TMA and TMAO production reduces thrombosis potential, a critical adverse complication in heart disease. They also offer a generalizable approach for the selective nonlethal targeting of gut microbial enzymes linked to host disease limiting systemic exposure of the inhibitor in the host.

Clopidogrel bisulfate (Plavix) does not increase bleeding complications in patients undergoing rubber band ligation for symptomatic hemorrhoids

BACKGROUND

The incidence of postprocedural bleeding in patients undergoing rubber band ligation (RBL) for symptomatic internal hemorrhoids while taking clopidogrel bisulfate is unknown. To determine the postprocedural bleeding risk of RBL for patients taking clopidogrel compared with age- and sex-matched controls.

MATERIALS AND METHODS

This is a retrospective case-controlled cohort study analyzing data from 2005 to 2013 conducted at a single tertiary care academic center. The study included a total of 80 rubber bands placed on 41 patients taking clopidogrel bisulfate and 72 bands placed on 41 control patients not taking clopidogrel matched for age and sex. The 30-d rates of significant and insignificant bleeding events after RBL were recorded. A bleeding event was considered significant if the patient required admission to the hospital, transfusion of blood products, or additional procedures to stop the bleeding. Insignificant bleeding was defined as passage of blood or clots per rectum with spontaneous cessation and no need for additional intervention.

RESULTS

There was no significant difference in the number of bleeding events per band placed in the clopidogrel group when compared with the control group (3.75% versus 2.78%, P = 0.7387). The rate of significant (2.5% versus 1.39%, P = 0.6244) and insignificant bleeding events (1.25% versus 1.39%, P = 0.9399) was also similar between the two groups. Two significant bleeding events occurred in the clopidogrel group requiring intervention: cauterization in one patient and colonoscopy and transfusion in the other.

CONCLUSIONS

The risk of a bleeding complication after RBL for hemorrhoids does not appear to be increased in patients taking clopidogrel. Our results support the practice of continuing clopidogrel bisulfate in the periprocedural period as the associated risk of thrombosis is greater than the risk of bleeding.

Uncertain Associations of Major Bleeding and Concurrent Use of Antiplatelet Agents and Chinese Medications: A Nested Case-Crossover Study

Despite the evidence that some commonly used Chinese medications (CMs) have antiplatelet/anticoagulant effects, many patients still used antiplatelets combined with CMs. We conducted a nested case-crossover study to examine the associations between the concomitant use of antiplatelets and CMs and major bleeding using population-based health database in Taiwan. Among the cohort of 79,463 outpatients prescribed antiplatelets (e.g., aspirin and clopidogrel) continuously, 1,209 patients hospitalized with new occurring bleeding in 2012 and 2013 were included. Those recruited patients served as their own controls to compare different times of exposure to prespecified CMs (e.g., Asian ginseng and dong quai) and antiplatelet agents. The periods of case, control 1, and control 2 were defined as 1–4 weeks, 6–9 weeks, and 13–16 weeks before hospitalization, respectively. Conditional logistic regression analyses found that concurrent use of antiplatelet drugs with any of the prespecified CMs in the case period might not significantly increase the risks of bleeding over that in the control periods (OR = 1.00, 95% CI 0.51 to 1.95 and OR = 1.13, 95% CI 0.65 to 1.97). The study showed no strong relationships between hospitalization for major bleeding events and concurrent use of antiplatelet drugs with the prespecified CMs.

Primary prevention aspirin use in high-risk patients: A pharmacist intervention and comparison of risk stratification tools

OBJECTIVES

The objectives of this project are 1) to describe aspirin use for primary prevention in an underserved, minority population; 2) to determine the impact of a pharmacist-led intervention on the prevalence of aspirin use for primary prevention; and 3) to compare aspirin indications based on Framingham Risk Score (FRS) and atherosclerotic cardiovascular disease (ASCVD) risk score.

METHODS

Men and women age 45-79 and 55-79 years, respectively, without ASCVD were screened for aspirin use. An FRS of 10% or greater and low risk for a serious bleed were considered indications for primary prevention aspirin on the basis of guideline-directed medical therapy recommendations. When treatment with aspirin was indicated, providers were notified with patient-specific messages. Patients' FRS and ASCVD risk score distributions were plotted and compared. Primary prevention aspirin indications were identified using both risk stratification tools.

RESULTS

One hundred sixteen patients were evaluated for aspirin use in a predominantly black (80%), middle-aged (mean age, 58 years), and indigent population. Thirty-one patients (27%) had an FRS of 10% or greater and low risk for bleeding, and 10 patients (9%) were taking aspirin at baseline. Providers approved recommendations to start administering aspirin in 19 of 31 patients (61%), which significantly increased the overall proportion receiving aspirin compared to baseline (9%-25%; P < 0.01). Patients were more than twice as likely to meet the minimum risk score threshold (≥10%) for a primary prevention aspirin indication using ASCVD risk scores versus FRS (70% vs. 30%; P < 0.01).

CONCLUSIONS

Baseline utilization of primary prevention aspirin was low in an indigent, minority population. A provider-focused pharmacist intervention improved the prevalence of aspirin use for primary prevention, while minimizing risk for serious bleeding events. Among our cohort, more patients had indications for primary prevention aspirin using ASCVD risk scores versus FRS.

Proton pump inhibitors are associated with lower gastrointestinal tract bleeding in low-dose aspirin users with ischaemic heart disease

BACKGROUND

Impact of acid suppressants on lower gastrointestinal bleeding remains unclear in low-dose aspirin users; we aimed to investigate this relationship.

METHODS

Retrospective cohort study of low-dose aspirin users who underwent coronary angiography for ischaemic heart disease in our institution between October 2005 and December 2006; patients were evaluated for upper or lower gastrointestinal bleedings within 3 years post-angiography.

RESULTS

538 patients were enrolled (males, 74.4%; mean age 67.4±10.6 years). Risk for upper gastrointestinal bleeding decreased with concomitant use of statins (HR, 0.37; 95% CI, 0.15-0.89), calcium channel blockers (HR, 0.29; 95% CI, 0.10-0.85), and histamine-2 receptor antagonists (HR, 0.26; 95% CI, 0.08-0.89). Concomitant use of proton pump inhibitors tended to decrease risk of upper gastrointestinal bleeding (HR, 0.27; 95% CI, 0.06-1.18). Risk for lower gastrointestinal bleeding increased with both concomitant use of warfarin (HR, 15.68; 95% CI, 4.43-55.53) and proton pump inhibitors (HR, 6.55; 95% CI, 2.01-21.32), but not with histamine-2 receptor antagonists. Hyperuricemia lowered risk for lower gastrointestinal bleeding (HR, 0.12; 95% CI, 0.02-0.88).

CONCLUSIONS

In low-dose aspirin users, concomitant use of proton pump inhibitors increased lower gastrointestinal bleeding risk, independent from effects on upper gastrointestinal bleeding.

Do we have to stop anticoagulant and platelet-inhibitor treatments during proctological surgery?

AIM

This prospective observation study evaluated the incidence of secondary bleeding after proctological surgery without interruption of oral anticoagulant or platelet-inhibitor treatments.

METHOD

The number of episodes of postoperative bleeding was identified prospectively from the day of surgery to the last follow-up visit in consecutive patients operated on during 2010 in two units dedicated to proctology.

RESULTS

A total of 2513 procedures were performed in 2314 patients (1379 men), 46 ± 16 years of age. Secondary bleeding occurred after 115 (4.6%) procedures, no later than day 24 after surgery, requiring rehospitalization in 86% of cases and further surgery and/or transfusion in 36%. The highest frequency was noted after surgery for haemorrhoids (haemorrhoidopexy, 7.9%; haemorrhoidectomy, 6.2%) (P = NS and transanal excision of rectal tumours (6.5%). On multivariate analysis, the frequency was significantly increased by clopidogrel (15%) [relative risk (RR) = 10). In patients on oral anticoagulants, bleeding occurred in 23% (RR = 5.8) if the anticoagulants were not interrupted and in 57% (RR = 42) if the anticoagulants were discontinued and replaced with heparin.

CONCLUSION

During proctological surgery the overall risk of postoperative bleeding is low, but it can occur up to 3 weeks after surgery and is often severe. Maintenance treatment with oral anticoagulants is the most important risk factor, aggravated by a change to heparin. Clopidogrel also significantly increases the bleeding risk.

Differential propensity for major hemorrhagic events in patients with different types of arterial disease

AIMS

Atherosclerosis is the most frequent cause of coronary artery disease (CAD), cerebrovascular disease (CVD), and peripheral arterial obstructive disease (PAD). We previously found that patients with CVD or PAD had a two-fold higher risk of major hemorrhagic complications than patients with CAD. We investigated whether this difference was attributable to baseline risk factors or genetic variants involved in hemostasis.

METHODS AND RESULTS

We included 2622 consecutive patients from a single university hospital who presented with non-disabling CAD, CVD, or PAD. All patients were followed for the occurrence of major hemorrhagic complications for a mean of 6.6 years. Major hemorrhagic events included intracranial hemorrhagic events, fatal hemorrhagic events, and any hemorrhagic complications requiring hospitalization, irrespective of interventions. Major hemorrhagic complications occurred in 122 patients (annual event rate of 0.77%). Patients with CVD or PAD had more hemorrhagic complications than patients with CAD (hazard ratio [HR] 2.05, 95% confidence interval [CI] 1.39-3.01). Hypertension, diabetes, renal failure and use of oral anticoagulants or antiplatelet therapy did not explain the difference (HR adjusted for all characteristics 1.74; 95% CI 1.14-2.61). Additional adjustment for genetic variants did not further change the HR.

CONCLUSION

Patients with CVD or PAD are at higher risk for major hemorrhagic events than patients with CAD. This difference could not be explained by known risk factors, use of antithrombotic agents, or genetic variants involved in hemostasis. Further research to find the reason for this difference and possible differences in pathogenesis is warranted.

Prospective survey of secondary bleeding following anorectal surgery in a consecutive series of 1,269 patients

INTRODUCTION

As little data is available about secondary bleeding after proctological surgery, we conducted a specific survey.

PATIENTS AND METHODS

Patients operated between November 2008 and April 2009 were prospectively included. Patients were followed until last visit (day 21-28). Severity of bleeding was low (at home stay), moderate (hospitalisation for observation), or severe (transfusion, and/or homeostasis in operating room).

RESULTS

Included were 1269 patients: haemorrhoidectomy/pexy 527 (41%), fistula treatment 273 (21%), fissurectomy 197 (15%), perianal and pilonidal abscesses 124 (10%), others 148 (12%). Before surgery 78 patients were under long-term treatment with antiplatelet or anticoagulant therapy. Seventy-eight patients (6%) demonstrated 85 bleeding events. Severity rate was: low 22%, moderate 51%, and severe 27%. Ninety-five percent of events occurred before day 15. Univariate study showed increased risk after haemorrhoidopexy (P<10-3) and anticoagulant treatment (P = 0.002), decreased risk after fissurectomy and fistulotomy (P<10-3), and no relation with age, sex or operator. After multivariate study only relationship with anticoagulant treatment remained significant.

CONCLUSION

Secondary bleeding occurred in 6% of patients after proctological surgery, requiring a readmission and/or an active treatment in about 75%. Treatment with anticoagulant exposed to increased bleeding frequency.

A novel gelatin sponge for accelerated hemostasis

To more effectively manage the substantial bleeding encountered during surgical procedures in oto-rhino-laryngology, we developed a novel hemostatic sponge made of pharmaceutical grade, chemically cross-linked gelatin. The sponge is characterized by a high pore density, reduced ligaments, and a high nanoscale roughness of lamella surfaces in the matrix. In vitro blood uptake assays revealed a very rapid absorption of human blood, which was two to three times faster than that measured with comparative hemostyptic devices. In an in vitro hemorrhage model using human veins, the novel gelatin sponge matrix induced hemostasis less than a minute after bleeding was induced. The sponge was shown to bring about rapid hemostasis when it was administered in a young patient suffering from acute bleeding of a pharyngeal angiofibroma, even though the patient had been treated with an anticoagulant because of a transient ischemic attack. As the gelatin matrix of the sponge is biocompatible and resorbable, the hemostyptic device could be left in place and was shown to be resorbed within 2 weeks. We hypothesize that the excellent hemostatic performance of the sponge might be linked to enhanced capillary effects in conjunction with optimized anchoring of fibrinogen on the nano-rough material surface, as suggested by scanning electron microscopy. The novel gelatin sponge appears to be a promising hemostatic matrix, which could be of great benefit for patients suffering from epistaxis and other acute injuries resulting in severe bleeding.

Gastrointestinal bleeding associated with low-dose aspirin use: relevance and management in clinical practice

IMPORTANCE OF THE FIELD

Aspirin reduces the risk of cardiovascular events, but it is well documented that it can also damage the gastrointestinal (GI) tract. However, the reasons why some people develop serious lesions, whereas most only have minor, clinically irrelevant lesions are poorly understood.

AREAS COVERED IN THIS REVIEW

A number of risk factors can be used to determine which patients are more likely to develop aspirin-associated GI bleeding, mainly in the upper GI tract; these include a previous GI ulcer, ulcer complications, dyspepsia, and concomitant drug therapy with non-steroidal anti-inflammatory drugs (NSAIDs) or clopidogrel. The possible role of Helicobacter pylori infection is also considered.

WHAT THE READER WILL GAIN

Aspirin-induced GI damage can be reduced, and a number of strategies can be implemented to shift the risk-benefit ratio in favour of aspirin. Proton pump inhibitors are more effective than H(2)-receptor antagonists in preventing dyspeptic symptoms, peptic ulcers and bleeding ulcers in aspirin users. Although H. pylori infection may be a risk factor of aspirin-induced ulcer bleeding, the role of its eradication in the prevention of this outcome requires further investigation.

TAKE HOME MESSAGE

The individual assessment of the benefits and risks with aspirin, based on the underlying GI and cardiovascular risk factors, is the key to successful therapy. Understanding the effect of aspirin on colorectal cancer can also alter the risk-benefit ratio in at-risk aspirin users.

Physicians' attitudes toward post-MI aspirin prophylaxis: findings from an online questionnaire in Asia-Pacific

Mortality from cardiovascular diseases, such as myocardial infarction (MI), is predicted to increase dramatically in Asia-Pacific countries. However, there are few studies that estimate utilization of prophylactics, such as low-dose aspirin, in these countries. To determine this, an online survey was sent to physicians in 18 countries worldwide, and this article reports the findings from the Asia-Pacific region (N = 4372 respondents). The overall mean number of MI patients per respondent was 246 in the Asia-Pacific countries, and 55% of physicians (overall) rated their patient as having total compliance with aspirin. The use of aspirin monotherapy or combination therapy, aspirin dosage, and physician contact were all found to have a significant impact on compliance (all P < 0.00001). Educational material on the role of aspirin was ranked as the most effective measure to improve compliance. In conclusion, this survey indicates that educational initiatives on secondary prevention are urgently needed in Asia-Pacific countries.