Optimizing long-term dual aspirin/clopidogrel therapy in acute coronary syndromes: When does the risk outweigh the benefit?

A retrospective study of antithrombotic therapy use in an outpatient haemodialysis unit

WHAT IS KNOWN AND OBJECTIVE

Patients on haemodialysis (HD) are at increased risk of both bleeding and thrombotic events, due to comorbidities and nature of dialysis treatment. However, there is a lack of research on evidence-based treatment strategies and prescribing patterns for antithrombotic therapies (ATT) in this population. To characterize ATT use and its main indications in an outpatient HD unit.

METHODS

A single-centre retrospective chart review was conducted in a Toronto outpatient HD unit (n = 329). Medical histories, number of ATTs and corresponding indications were collected from adult patients prescribed at least one ATT from 1 October 2019 to 31 December 2019, inclusive.

RESULTS AND DISCUSSION

Of 329 patients in the unit, a total of 135 (41%) patients were on at least one ATT. Of these 135 patients, 80% were on monotherapy (55% antiplatelet, 25.1% anticoagulant), 12.6% were on dual antiplatelet therapy (DAPT), and 7.4% were on a antiplatelet and anticoagulant combination. Primary indications for ATT in our cohort were coronary artery disease (CAD; 55%), atrial fibrillation (18.5%) and venous thromboembolism (VTE; 17%). Described ATT use was in-line with current clinical guidelines. Monotherapy was primarily used in our HD cohort, whereas few patients were on dual therapy. Low-dose aspirin was the most common antiplatelet prescribed for secondary prevention of cardiovascular events. Warfarin monotherapy was primarily indicated for VTE, and DAPT aspirin/clopidogrel was the most commonly prescribed for CAD.

WHAT IS NEW AND CONCLUSION

Our characterization of ATT use in this HD cohort demonstrates that ATT is often prescribed for a number of different CVD reasons. Overlapping and confounding indications for prescribing ATTs, lack of randomized controlled trials and unclear clinical guidelines mean that individualized risk-benefit assessments for ATT use are still needed to provide care for these high-risk patients. More research to address the safety and efficacy of ATTs is warranted to develop more robust evidence-based treatment guidelines for the HD population.

Clopidogrel and the risk of osteoporotic fractures: a nationwide cohort study

OBJECTIVES

The P2Y(12) inhibitor clopidogrel inhibits platelet aggregation and is used in the treatment and prevention of coronary artery disease. It is widely used and, in combination with acetylsalicylic acid, is the standard of care for acute coronary syndrome and percutaneous coronary intervention. The mode of action of clopidogrel involves pathways that are important to the metabolic activity in bone cells, although to our knowledge whether P2Y(12) receptors are involved in the regulation of bone metabolism has not yet been investigated. Therefore, the objective of the present study was to investigate the association between clopidogrel use and risk of fractures.

METHODS

We investigated the association between clopidogrel use and fracture incidence in a nationwide cohort study within the Danish population of approximately 5.3 million individuals. All patients who were prescribed clopidogrel during the years 1996-2008 were included in the study (n = 77 503), and three nonusers were randomly selected, matched for age and gender (n = 232 510), for each clopidogrel-treated subject.

RESULTS

Treatment with clopidogrel was associated with both increased overall fracture risk and increased risk of osteoporotic fractures, especially in subjects with a treatment duration of more than 1 year. However, individuals with low exposure to clopidogrel (<0.01 defined daily dose) had a lower risk of fracture than never users.

CONCLUSIONS

Use of the P2Y(12) inhibitor clopidogrel is associated with risk of fractures. There seems to be a biphasic relation so that lower doses are associated with decreased fracture risk, whereas higher doses (recommended dose range) are associated with increased risk. More studies are warranted to determine the potential in vivo effect of platelet aggregation inhibitors on bone metabolism.

Primary endpoint results of the EVOLVE trial: a randomized evaluation of a novel bioabsorbable polymer-coated, everolimus-eluting coronary stent

OBJECTIVES

This study sought to compare the safety and efficacy of 2 dose formulations of SYNERGY, a novel bioabsorbable polymer everolimus-eluting stent (EES) (Boston Scientific Corp., Natick, Massachusetts) compared with the durable polymer PROMUS Element EES (Boston Scientific Corp.).

BACKGROUND

Durable polymer coatings on drug-eluting stents have been associated with chronic inflammation and impaired healing. Bioabsorbable polymer-coated drug-delivery systems may reduce the risk of late adverse events, including stent thrombosis, and thus the need for prolonged dual-antiplatelet therapy.

METHODS

A total of 291 patients with a de novo lesion ≤28 mm in length, in a coronary artery of ≥2.25 to ≤3.5 mm diameter, were enrolled in the EVOLVE study, a prospective, randomized, single-blind, noninferiority trial. Patients were randomly assigned in a 1:1:1 ratio to PROMUS Element, SYNERGY, or SYNERGY half dose. The primary clinical endpoint was the 30-day rate of target lesion failure, defined as cardiac death or myocardial infarction related to the target vessel, or target lesion revascularization. The primary angiographic endpoint was 6-month in-stent late loss measured by quantitative coronary angiography.

RESULTS

The 30-day primary clinical endpoint of target lesion failure occurred in 0%, 1.1%, and 3.1% of patients in the PROMUS Element, SYNERGY, and SYNERGY half dose groups, respectively. The 6-month in-stent late loss was 0.15 ± 0.34 mm for PROMUS Element, 0.10 ± 0.25 mm for SYNERGY, and 0.13 ± 0.26 mm for SYNERGY half dose (SYNERGY, difference -0.06, upper 95.2% confidence limit: 0.02, p for noninferiority <0.001; SYNERGY half dose, difference -0.03, upper 95.2% confidence limit: 0.05, p for noninferiority <0.001). Clinical event rates remained low and comparable between groups, with no stent thromboses in any group at 6 months.

CONCLUSIONS

The EVOLVE trial confirms the effective delivery of everolimus by a unique directional bioabsorbable polymer system utilizing the SYNERGY stent. (A Prospective Randomized Multicenter Single-Blind Noninferiority Trial to Assess the Safety and Performance of the Evolution Everolimus-Eluting Monorail Coronary Stent System [Evolution Stent System] for the Treatment of a De Novo Atherosclerotic Lesion [EVOLVE]; NCT01135225).