Bayer AG’s Trasylol, often used to prevent blood loss during heart surgery, will be pulled from the market after a long-waited Canadian study found it raised the risk of death by 53 percent, the U.S. Food and Drug Administration said in a statement on Wednesday.

Trasylol was approved in the U.S. in 1993 to reduce transfusions and bleeding during open-heart surgery. The drug became a mainstay of care, generating about $333 million in 2005.

The study released Wednesday by the New England Journal of Medicine and named “Blood Conservation using Antifibrinolytics in a Randomized Trial (BART) was done on 2,331 patients who had undergone heart surgery in 19 Canadian hospitals. Its findings confirmed earlier findings, meaning the drug raised the risk of death by 53 percent. The study found that 6 percent of patients given Trasylol or aprotinin died within 30 days of surgery compared to 4 percent of patients given tranexamic aci or aminocaproic acid. All three dugs are used to prevent blood loss during heart surgery.

"Of the 108 patients who died, the proportion who were believed to have died of cardiogenic shock, right ventricular failure, congestive heart failure or myocardial infarction (heart attack) was higher in the aprotinin group than in the other two groups," Dean Fergusson of the Ottawa Health Research Institute and colleagues wrote.

“The most important outcome of the trial was a bit of surprise,” co-principal investigator Dr. Paul C. Hebert, a critical care physician at Ottawa Hospital, said during a teleconference on Monday, the Washington Post reports.

Because of the increased risk of death, the study was halted in October 2007, before the scheduled completion date. Dr. Hebert said clearly the drug shouldn’t be used for high-risk cardiac surgery patients. “This study could have been done by the company five to ten years ago,” he said, adding that Trasylol costs about $1,400 compared to about $4 for aminocaproic acid.

The FDA said Wednesday Bayer notified the agency that it would begin removing Trasylol stock from the U.S. market. In fact, Bayer said it was removing Trasylol supplies from all countries where it remained in the supply chain, except where local authorities wanted to keep it in the market for special access programs.

According to Bayer, as of early May, U.S. patients have filed 83 lawsuits against it over Trasylol.