Ticagrelor may not confer post-MI benefits to elderly patients

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CARDIOVASCULAR DISEASE

Medical writer: Kirsty LEE | Last updated: 8th October 2020 | In: Cardiovascular

Article Keywords

ACS, acute coronary syndrome, aspirin, clopidogrel, DAPT, dual anti-platelet therapy, myocardial infarction, NSTEMI, P2Y12 antagonist, P2Y12 receptor inhibitor, platelet aggregation, STEMI, stroke, ticagrelor

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y₁₂ receptor inhibitor is the standard treatment for acute coronary syndrome (ACS).¹ Clopidogrel and ticagrelor are both P2Y₁₂ receptor antagonists.² Clopidogrel is an irreversible antagonist with a variable degree of platelet inhibition within the population, whereas ticagrelor is an orally active reversibly binding inhibitor with rapid onset of induced platelet aggregation.² Ticagrelor was studied in a large, multicentre, randomised, double-blind PLATO trial, and showed a 16% relative risk reduction in composite cardiovascular death, myocardial infarction (MI), or stroke compared to clopidogrel.²

However, recent analysis of the SWEDEHEART Registry, has indicated that ticagrelor use among elderly MI patients was associated with a higher risk of bleeding and death than with clopidogrel.³ The results were recently published in Circulation.³

SWEDEHEART is a nationwide registry in Sweden that includes all consecutive patients admitted to a coronary care unit with symptoms that suggest ACS.³ Variables including baseline patient characteristics, medication on admission, in-hospital therapies, complications, and discharge medicines are collected.³ Inverse probability treatment weighting (IPTW) was used in analysis to reduce selection bias as treatments were not randomly assigned.³ The registry was used to compare clinical outcomes with ticagrelor versus clopidogrel among MI patients aged ≥80.³

Of the 14,005 patients aged ≥80 who survived until discharge after an MI, 31.6% had a ST-segment elevation MI (STEMI) and 68.4% had a non-ST segment elevation MI (NSTEMI).³ The majority (60.2%) were prescribed clopidogrel, and 39.8% were prescribed ticagrelor.³ Patients who received ticagrelor were younger and had fewer comorbidities at presentation.³ After Inverse Probability of Treatment Weighting (IPTW) adjustment, baseline characteristics were balanced.³

The unadjusted analysis showed that patients treated with ticagrelor had significantly fewer combined ischaemic events or combined ischaemic/bleeding events.³ However, after IPTW Cox regression there was no significant reduction in combined ischaemic or combined ischaemic/bleeding endpoints with ticagrelor compared with clopidogrel treatment.³ Ticagrelor-treated patients had a 20% and 28% lower risk of new MI or stroke, respectively, compared with clopidogrel patients within one year.³ However, patients receiving ticagrelor had a 17% higher risk of dying and a 48% higher risk of re-admission due to a bleeding event than those treated with clopidogrel.³ In patients younger than 80 years, there was an 18% lower risk of MI, 18% lower risk of stroke, and a 15% lower risk of death, but 32% higher risk of bleeding events.³

The results of this analysis indicate that current guideline recommendations should be applied with caution to the elderly population.³ There has been significant uptake in ticagrelor use over the study period, and nearly three quarters of all elderly patients at the end of 2017 were prescribed ticagrelor at discharger after a MI.³ Thus, there is a need for a randomised controlled study to examine the effects of antiplatelet medications in the elderly population.³

Reference

Wang D et al. BMC Cardiovasc Disord. 2018;18.

Shand JA et al. Biomark Med. 2011;5(1):53-62.

Szummer Karolina et al. Circulation. doi: 10.1161/CIRCULATIONAHA.120.050645

Disclaimer

This article is not medical advice. Patients should seek personal assessment by a licenced specialist. Physicians are recommended to read the full publication(s) as cited in the article before making medical decisions. This article does not supersede nor replace the published article(s).