{"id":6551,"date":"2011-02-18T12:03:51","date_gmt":"2011-02-18T17:03:51","guid":{"rendered":"http:\/\/blogs.nejm.org\/cardioexchange\/?p=6551"},"modified":"2011-07-19T17:44:06","modified_gmt":"2011-07-19T21:44:06","slug":"a-case-of-clopidgrel-nonresponsiveness","status":"publish","type":"post","link":"https:\/\/blogs.nejm.org\/cardioexchange\/2011\/02\/18\/a-case-of-clopidgrel-nonresponsiveness\/","title":{"rendered":"A Case of Clopidogrel Nonresponsiveness?"},"content":{"rendered":"<p><em>This latest installment in our case discussion series is submitted by <a href=\"http:\/\/blogs.nejm.org\/cardioexchange\/members\/tariqahmad627\/\">Tariq Ahmad, MD, MPH<\/a>.  We encourage members to submit cases that they believe warrant  discussion. Selected cases will be presented to the community, and case  authors will receive a $100 Amazon gift card.<\/em><\/p>\n<p>A 70-year-old woman presents to the ED with an anterior STEMI. She had a stroke 3 months prior and an MI 5 months prior to that, with DES to the LAD. She is morbidly obese and has hypertension, hyperlipidemia, and peripheral artery disease with bilateral carotid stenosis. Soon after arriving in the ED, she goes into cardiac arrest and is found to be in ventricular tachycardia\/fibrillation. After a 15-minute resuscitation that includes intubation, she is taken to the catheterization lab, where a thrombus is found in her LAD stent. She undergoes PCI with a BMS to the LAD. During the procedure, she has significant hemodynamic instability and requires an intra-aortic balloon pump. She is admitted to the CCU for further management.<\/p>\n<p>According to her family, she has been adherent to her clopidogrel. A VerifyNow P2Y12 platelet function test shows 0% P2Y12 inhibition.<\/p>\n<p>Questions:<\/p>\n<ul>\n<li>Do you feel fairly confident, based on the VerifyNow test, that this patient is a clopidogrel nonresponder?<\/li>\n<li>Would you perform any additional testing to assess whether she is a clopidogrel nonresponder?<\/li>\n<li>Would you increase the clopidogrel dose or give an alternate agent?<\/li>\n<\/ul>\n<p><strong>Response<\/strong><\/p>\n<p><a href=\"http:\/\/blogs.nejm.org\/cardioexchange\/members\/jamesfang\/\">James Fang, MD<\/a><\/p>\n<p>The most common cause of clopidogrel &#8220;resistance&#8221; (and for that matter, aspirin &#8220;resistance&#8221;) remains noncompliance. The &#8220;0%&#8221; P2Y12 inhibition with VerifyNow is highly suspicious for noncompliance despite the report from the patient&#8217;s family. I am not confident that she is a clopidogrel nonresponder. I would recommend that she be given clopidogrel in the CCU and have her platelet reactivity retested in 48 hours.<\/p>\n<p>If the test demonstrates nonresponsiveness, then I would consider using prasugrel despite the risks, which would need to be reviewed with the patient and family. The issue of increased intracerebral bleeding is not trivial with prasugrel (e.g., age, prior stroke). To further minimize risk, the duration of therapy with prasugrel could be limited since a bare metal stent was used. Another option is clopidogrel at 150 mg daily, although the findings of <a href=\"http:\/\/blogs.nejm.org\/cardioexchange\/gravitas-no-benefit-for-clopidogrel-dosing-based-on-platelet-function-test\/\">GRAVITAS<\/a> and <a href=\"http:\/\/blogs.nejm.org\/cardioexchange\/clopidogrel-and-aspirin-dosages-scrutinized-in-current-oasis-7-papers-and-editorials\/\">OASIS-7<\/a> make this choice less than ideal. Ticagrelor will soon be available as another option. Some would consider adding cilostazol. Finally, it should be kept in mind that stent thrombosis is not just an issue of P2Y12 inhibition; there are patient- and procedural-related factors, as well.<\/p>\n<p>The issue of routine assessment of platelet function after PCI is evolving and is not yet the standard of care. The &#8220;negative&#8221; results of GRAVITAS and OASIS-7 have made this issue even more complicated, however, this may be more of an indictment of clopidogrel rather than the concept of measuring platelet reactivity.<\/p>\n<p>Which platelet assay to use? VerifyNow has the greatest clinical data available in human studies, however, both VerifyNow and PlateWorks have good discriminating ability for important clinical endpoints and both are relatively easy to use at the bedside. The POPULAR study (<a href=\"http:\/\/jama.ama-assn.org\/content\/303\/8\/754.abstract\"><em>JAMA<\/em> 2010; 303:754<\/a>) is worth reviewing in this regard.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>This latest installment in our case discussion series is submitted by Tariq Ahmad, MD, MPH. We encourage members to submit cases that they believe warrant discussion. Selected cases will be presented to the community, and case authors will receive a $100 Amazon gift card. A 70-year-old woman presents to the ED with an anterior STEMI. [&hellip;]<\/p>\n","protected":false},"author":494,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,9],"tags":[334,257,437],"class_list":["post-6551","post","type-post","status-publish","format-standard","hentry","category-general","category-interventional-cardiology","tag-clopidogrel","tag-stemi","tag-stents"],"_links":{"self":[{"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/posts\/6551","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/users\/494"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/comments?post=6551"}],"version-history":[{"count":0,"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/posts\/6551\/revisions"}],"wp:attachment":[{"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/media?parent=6551"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/categories?post=6551"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/tags?post=6551"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}