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LETTERS: Andrew J Wiper and David H Roberts Stent thrombosis: Consider also low response to antiplatelets BMJ 2007; 334: 57-b [Full text]

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Aspirin Resistance

Mahmood Ahmad, Noreen Khan, Ambreen Khan, Mehboob Ahmed Rehan, Rizwan Mahmood,Dr J San Agustin   (28 January 2007)

Aspirin Resistance 28 January 2007
Mahmood Ahmad, CTF-HO Medway Maritime Hospital, Windmill Road, Gillingham, Noreen Khan, Ambreen Khan, Mehboob Ahmed Rehan, Rizwan Mahmood,Dr J San Agustin Send response to journal: Re: Aspirin Resistance	The term aspirin resistance indicates a lack of pharmacologic effects of aspirin on platelets but also poor clinical outcomes, such as recurrent vascular events, in patients treated with aspirin.1 Aspirin resistance is a measurable, persisting platelet activation that occurs in patients prescribed a therapeutic dose of aspirin.2 Arterial wall injury caused by percutaneous coronary intervention (PCI) triggers transient platelet activation on top of the platelet hyperreactivity associated with underlying atherothrombosis. Platelet activation has been implicated in both acute and subacute thrombosis and restenosis secondary to PCI.3 Several studies have now shown that a substantial minority of patients may have either total or partial aspirin resistance. Although these studies may have methodological differences, they suggest that between 5% and 55% of treated patients may have some degree of aspirin resistance.4, 5 1: Mayo Clin Proc. 2006 May;81(5):641-52. Stent thrombosis may occur later with drug eluting stents than with bare metal stents (which themselves have the complication of restenosis) potentially many months after the procedure. The British Cardiovascular Interventional Society has recently recommended that dual antiplatelet therapy should be continued for one year in all patients having drug eluting stents inserted.5 Lev EI, Patel RT, Maresh KJ, Guthikonda S, Granada J, DeLao T, Bray PF, Kleiman NS. 1.Narrative review: aspirin resistance and its clinical implications. Sanderson S, Emery J, Baglin T, Kinmonth AL.Ann Intern Med. 2005 Mar 1;142(5):370-80. 2 1: Ann Intern Med. 2005 Mar 1;142(5):370-80. Narrative review: aspirin resistance and its clinical implications. 3 A H Gershlick, G Richardson BMJ. 2006 Dec 16;333(7581):1233-4. 4 Ann Intern Med. 2005 Mar 1;142(5):370-80. Narrative review: aspirin resistance and its clinical implications. Sanderson S, Emery J, Baglin T, Kinmonth AL. 5 Aspirin for everyone over 50? Don't forget aspirin resistance. Dhatariya KK.BMJ. 2005 Jul 16;331(7509):161; author reply 161. Competing interests: None declared