{"id":4835,"date":"2010-11-16T10:22:58","date_gmt":"2010-11-16T15:22:58","guid":{"rendered":"http:\/\/blogs.nejm.org\/cardioexchange\/?p=4835"},"modified":"2011-07-19T17:44:42","modified_gmt":"2011-07-19T21:44:42","slug":"gravitas-no-benefit-for-clopidogrel-dosing-based-on-platelet-function-test","status":"publish","type":"post","link":"https:\/\/blogs.nejm.org\/cardioexchange\/2010\/11\/16\/gravitas-no-benefit-for-clopidogrel-dosing-based-on-platelet-function-test\/","title":{"rendered":"GRAVITAS: No Benefit for Clopidogrel Dosing Based on Platelet Function Test"},"content":{"rendered":"<div>\n<p>The GRAVITAS (Gauging Responsiveness With A VerifyNow Assay \u2500 Impact on Thrombosis and Safety) trial enrolled\u00a02214 patients with high residual platelet reactivity, as assessed by the VerifyNow P2Y12 Test measured 12 to 24 hours after the procedure. (The manufacturer of the test, Accumetrics, sponsored the trial.) Patients in the trial were randomized to either\u00a0high-dose clopidogrel (additional loading dose, 150 mg daily thereafter) or standard-dose clopidogrel (no additional loading dose, 75 mg daily thereafter).<\/p>\n<p>The primary endpoint \u2500 a composite of CV death, MI, or stent thrombosis at 6 months \u2500 occurred in 2.3% of patients in each group. Bleeding complications also occurred at similar rates in the groups.<\/p>\n<p>&#8220;The high dose of clopidogrel doesn&#8217;t appear to improve outcomes, so alternative treatment strategies should be tested,&#8221; said Matthew Price, the lead investigator, in <a href=\"http:\/\/www.newsroom.heart.org\/index.php?s=43&amp;item=1195\">an AHA press release<\/a>. &#8220;Many physicians have been using a high dose of clopidogrel as a default strategy in patients who are nonresponsive to the drug. We show that this strategy is probably ineffective.&#8221;<\/p>\n<p><strong><em>CardioExchange&#8217;s Rick Lange and David Hillis weigh in on the findings:<\/em><\/strong><\/p>\n<p>The GRAVITAS study shows that high-dose clopidogrel doesn&#8217;t improve outcomes in patients with high residual platelet activity. An alternative interpretation is that assessment of platelet reactivity doesn\u2019t effectively identify individuals at high risk for a cardiovascular event following PCI.<\/p>\n<p>Of all patients considered for enrollment, more than 40% had high \u201con-treatment platelet reactivity\u201d (i.e., level of platelet reactivity during clopidogrel therapy), according to the VerifyNow P2Y12 Test \u2500 yet only 2.3% of them had a cardiovascular event in the 6 months following PCI. In essence, the positive predictive value of the test is low.\u00a0 Although the investigators call for testing &#8220;alternative treatment strategies&#8221; in patients with high platelet reactivity, it may be more worthwhile first to develop tests that are better at identifying individuals at high risk of having a cardiovascular event after PCI despite routine therapy. The notion that alteration of therapy based on platelet function measurements improves outcomes is still unproven.<\/p>\n<p><em><strong>Would you alter antiplatelet therapy based on currently available platelet reactivity studies?\u00a0 If so, how?<\/strong><\/em><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>The GRAVITAS (Gauging Responsiveness With A VerifyNow Assay \u2500 Impact on Thrombosis and Safety) trial enrolled\u00a02214 patients with high residual platelet reactivity, as assessed by the VerifyNow P2Y12 Test measured 12 to 24 hours after the procedure. (The manufacturer of the test, Accumetrics, sponsored the trial.) Patients in the trial were randomized to either\u00a0high-dose clopidogrel [&hellip;]<\/p>\n","protected":false},"author":196,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[334,564,565],"class_list":["post-4835","post","type-post","status-publish","format-standard","hentry","category-interventional-cardiology","tag-clopidogrel","tag-platelet-function-testing","tag-verifynow"],"_links":{"self":[{"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/posts\/4835","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\/196"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/comments?post=4835"}],"version-history":[{"count":0,"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/posts\/4835\/revisions"}],"wp:attachment":[{"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/media?parent=4835"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/categories?post=4835"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.nejm.org\/cardioexchange\/wp-json\/wp\/v2\/tags?post=4835"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}