The National Institutes of Health has awarded a University of Maryland scientist an $11.4 million, five-year grant to study whether anti-platelet drugs that prevent blood clots based on a patient's genetic makeup can be used to treat cardiac arrest.

The grant was given to Alan R. Shuldiner, a professor of medicine and director of the Program in Genetics and Genome Medicine at the University of Maryland School of Medicine.

The study of the 2,400 cardiac patients at 5 sites will build on previous research by Shuldiner. The research found that the anti-platelet drug Plavix is not effective for people who have a certain variant of gene. The variant appears to affect a person's ability to activate the drug.

Plavix prevents platelets from clumping together and causing blood clots that can lead to heart attacks and strokes.

People with the gene variant who take Plavix after angioplasty or having a stent implanted have more than twice the risk of dying or having cardiac problems from a blocked artery, Shuldiner said.

The Food and Drug Administration issued a warning to physicians and patients in March about the reduced effectiveness of the drug in patients with the gene variant.

Shuldiner will use the grant money to look at whether treatments geared to a patient's genetic makeup are more effective in treating cardiac ailments.

The grant is funded by the National Institute of Health National Heart, Lung and Blood Institute. The agency is is expanding its focus on understanding how a person's genes respond to certain medicines.

Shuldiner will work with other institutions including Johns Hopkins University and Sinai Hospital in Baltimore.