Featured Research

from universities, journals, and other organizations

Study examines outcomes of high-dose antiplatelet drug after stent placement

Date:
March 15, 2011
Source:
JAMA and Archives Journals
Summary:
Modifying a patient's dosage of the antiplatelet drug clopidogrel for 6 months depending on the patient's level of platelet reactivity did not result in combined lower rates of nonfatal heart attack, stent thrombosis (clot) and cardiovascular death in patients who had a procedure such as balloon angioplasty and received a drug-releasing coronary stent, according to a new study.

Modifying a patient's dosage of the antiplatelet drug clopidogrel for 6 months depending on the patient's level of platelet reactivity did not result in combined lower rates of nonfatal heart attack, stent thrombosis (clot) and cardiovascular death in patients who had a procedure such as balloon angioplasty and received a drug-releasing coronary stent, according to a study in the March 16 issue of JAMA.

Current guidelines recommend treating patients undergoing percutaneous coronary intervention (PCI; procedure such as balloon angioplasty used to open narrowed coronary arteries) and drug-eluting stent implantation with a combination of aspirin and P2Y12 (compound found on the surface of blood platelet cells and an important regulator in blood clotting) antagonist for at least 1 year. But several studies have suggested that patients with high platelet reactivity during treatment with clopidogrel are at an increased risk of cardiovascular events after PCI. A treatment strategy for this issue has not been well defined, according to background information in the article.

Matthew J. Price, M.D., of Scripps Translational Science Institute, La Jolla, Calif., and colleagues conducted the Gauging Responsiveness with A VerifyNow assay -- Impact on Thrombosis And Safety (GRAVITAS) trial to determine whether high-dose clopidogrel is superior to standard-dose therapy for the prevention of cardiovascular events after PCI in patients with high on-treatment reactivity. The randomized trial included 2,214 patients with high on-treatment reactivity (measured 12 to 24 hours after PCI) with drug-eluting stents at 83 centers in North America between July 2008 and April 2010. Patients received high-dose clopidogrel (600-mg initial dose, 150 mg daily thereafter) or standard-dose clopidogrel (75 mg daily) for 6 months. The primary outcome measured was the 6-month incidence of death from cardiovascular causes, nonfatal heart attack, or stent thrombosis. Safety measurements included severe or moderate bleeding.

The researchers found that the rate of death from cardiovascular causes, nonfatal heart attack, or stent thrombosis was not different with high-dose compared with standard-dose clopidogrel in the patients with high on-treatment reactivity (25 (2.3 percent) vs. 25 [2.3 percent]). In an analysis, the event rates in the 2 groups after 30 days were (20 [1.9 percent] vs. 17 [1.6 percent]), respectively.

The reduction in on-treatment reactivity at 30 days and at 6 months after randomization was significantly greater with high-dose than with standard-dose clopidogrel. High-dose clopidogrel was associated with an absolute 22 percent lower rate of high on-treatment reactivity compared with standard-dose clopidogrel at 30 days and 6 months (40 percent vs. 62 percent; and 36 percent vs. 60 percent, respectively).

Severe or moderate bleeding was not increased with the high-dose regimen.

"In conclusion, high-dose clopidogrel for 6 months in patients with high on-treatment platelet reactivity 12 to 24 hours after PCI with drug-eluting stents did not reduce the rate of death from cardiovascular causes, nonfatal myocardial infarction, or stent thrombosis compared with standard-dose clopidogrel. The results of GRAVITAS do not support a uniform treatment strategy of high-dose clopidogrel in patients with high on-treatment reactivity identified by a single platelet function test after PCI. Alternative treatment strategies incorporating platelet function testing merit further investigation," the authors write.

Editorial: An Initial Experiment With Personalized Antiplatelet Therapy

Paul A. Gurbel, M.D., and Udaya S. Tantry, Ph.D., of the Sinai Hospital of Baltimore, comment on the findings of this study in an accompanying editorial.

"… the GRAVITAS investigators have conducted the largest trial of personalized antiplatelet therapy thus far. The valuable information gained from the GRAVITAS trial can inform future trials. Even though GRAVITAS demonstrated that platelet function testing after drug-eluting stent placement does not improve outcomes if high-dose clopidogrel is used as the remedy, it is hoped that future studies evaluating different platelet function cutpoints and more potent P2Y12 inhibitors will be effective."


Story Source:

The above story is based on materials provided by JAMA and Archives Journals. Note: Materials may be edited for content and length.


Journal References:

  1. M. J. Price, P. B. Berger, P. S. Teirstein, J.-F. Tanguay, D. J. Angiolillo, D. Spriggs, S. Puri, M. Robbins, K. N. Garratt, O. F. Bertrand, M. E. Stillablower, J. R. Aragon, D. E. Kandzari, C. T. Stinis, M. S. Lee, S. V. Manoukian, C. P. Cannon, N. J. Schork, E. J. Topol. Standard- vs High-Dose Clopidogrel Based on Platelet Function Testing After Percutaneous Coronary Intervention: The GRAVITAS Randomized Trial. JAMA: The Journal of the American Medical Association, 2011; 305 (11): 1097 DOI: 10.1001/jama.2011.290
  2. P. A. Gurbel, U. S. Tantry. An Initial Experiment With Personalized Antiplatelet Therapy: The GRAVITAS Trial. JAMA: The Journal of the American Medical Association, 2011; 305 (11): 1136 DOI: 10.1001/jama.2011.332

Cite This Page:

JAMA and Archives Journals. "Study examines outcomes of high-dose antiplatelet drug after stent placement." ScienceDaily. ScienceDaily, 15 March 2011. <www.sciencedaily.com/releases/2011/03/110315163211.htm>.
JAMA and Archives Journals. (2011, March 15). Study examines outcomes of high-dose antiplatelet drug after stent placement. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2011/03/110315163211.htm
JAMA and Archives Journals. "Study examines outcomes of high-dose antiplatelet drug after stent placement." ScienceDaily. www.sciencedaily.com/releases/2011/03/110315163211.htm (accessed April 19, 2014).

Share This



More Health & Medicine News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Holy Grail' Of Weight Loss? New Find Could Be It

'Holy Grail' Of Weight Loss? New Find Could Be It

Newsy (Apr. 18, 2014) In a potential breakthrough for future obesity treatments, scientists have used MRI scans to pinpoint brown fat in a living adult for the first time. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com
Scientists Create Stem Cells From Adult Skin Cells

Scientists Create Stem Cells From Adult Skin Cells

Newsy (Apr. 17, 2014) The breakthrough could mean a cure for some serious diseases and even the possibility of human cloning, but it's all still a way off. Video provided by Newsy
Powered by NewsLook.com
Obama: 8 Million Healthcare Signups

Obama: 8 Million Healthcare Signups

AP (Apr. 17, 2014) President Barack Obama gave a briefing Thursday announcing 8 million people have signed up under the Affordable Care Act. He blasted continued Republican efforts to repeal the law. (April 17) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins