Half of patients undergoing cerebrovascular stent placement respond poorly to clopidogrel

A study by researchers at Rush University Medical Center, published in the February issue of the American Journal of Neuroradiology, finds that half of patients undergoing cerebrovascular stent placement did not respond well to clopidogrel. Clopidogrel (Plavix) and aspirin are medications routinely prescribed for 1-3 months following cerebrovascular stent placement to combat the risk of blood clots (stent-thrombosis) and reclosure of the artery (re-stenosis).

“Given the importance of platelet inhibition in the prevention of in-stent thrombosis and re-stenosis, there is a great incentive to ensure that adequate antiplatelet effects are achieved in high-risk patients,” said Dr. Shyam Prabhakaran, stroke neurologist at Rush University Medical Center.

The study reviewed 76 patients who underwent cerebrovascular stent placement for various clinical indications, including wide-neck aneurysm and intracranial stenosis. Researchers used the VerifyNow rapid platelet function assay-aspirin (RPFA-ASA) to calculate aspirin reaction units and the P2Y12 assay (VerifyNow) to calculate P2Y12 reaction units and percentage platelet inhibition immediately before the endovascular procedure.

In the 71 patients on aspirin in whom ARU was measured, only three patients had a low response to aspirin. Of the 55 patients in whom percentage platelet inhibition was measured, 28 patients (50.9%) had clopidogrel resistance. The researchers observed a significant association between older age (over the age of 55) and clopidogrel resistance and there was a strong effect of diabetes on platelet activity suggesting that these patients may require alternate approaches.

“Our study shows that using a point-of-care platelet function test in patients undergoing cerebrovascular stent placement is feasible and may be a valuable tool in the prevention of stent-related complications,” said Prabhakaran. “Akin to the international normalized ratio used for warfarin, platelet function tests provide objective measurement of antiplatelet efficacy and help tailor therapy on an individual basis.”

However, given these preliminary results, the researchers encourage further studies on ideal doses, timing, and duration of antiplatelet therapy for cerebrovascular stent placement.

Source: Rush University Medical Center

Related stories:

Study links depression to higher death rate from all causes among Medicare beneficiaries with diabetes
(PhysOrg.com) -- In a large group of Medicare beneficiaries with diabetes, depression was associated with a higher death rate from all causes during a two-year study period. The findings are published in the October 2008 Journal of General Internal Medicine.
Unusual case of a woman who suffered stroke during sex
Minutes after having sexual intercourse with her boyfriend, a 35-year-old woman suddenly felt her left arm go weak. Her speech became slurred and she lost feeling on the left side of her face.
Global study shows telmisartan reduces outcome of cardiovascular death, heart attack or stroke
An international study led by Canadian researchers has found that telmisartan, a medication used to lower blood pressure, reduced the outcome of cardiovascular death, heart attack or stroke in people who are unable to tolerate a widely available and effective standard treatment.
New method assesses risks for heart failure patients
Data from 260 hospitals across the United States has led to the creation of a new method for physicians to more accurately determine the severity of heart failure in patients upon hospital admission, with a goal of reducing in-hospital mortality and more quickly identifying triage methods and treatment decisions. The model is discussed in the July 29 issue of the Journal of the American College of Cardiology.
Researchers tap into a new and potentially better source of platelets for transfusion
Japanese researchers may be one step closer to improving treatments for bleeding disorders. A group of researchers from the University of Tokyo has devised a way to maximize the numbers and function of clot-forming blood cells from mice. Their work will be published online in the Journal of Experimental Medicine on July 28.
Combining medical knowledge to save lives
European researchers hope to gain more insight into cardiovascular disease by combining clinical, laboratory and metabolic records with genomic data.
Cardiovascular disease (CVD) is the biggest killer among chronic diseases, claiming 17 million lives globally every year. Yet doctors can only attribute 50% of cardiovascular diseases to known risk factors.
Erectile dysfunction lower in men who have intercourse more often
Having intercourse more often may help prevent the development of erectile dysfunction (ED). A study published in the July 2008 issue of The American Journal of Medicine reports that researchers have found that men who had intercourse more often were less likely to develop ED.
Cancer 'cure' in mice to be tested in humans
Scientists at Wake Forest University Baptist Medical Center are about to embark on a human trial to test whether a new cancer treatment will be as effective at eradicating cancer in humans as it has proven to be in mice.

News discussion:

Medicine & Health news