A new analysis concludes that the Food and Drug Administration approved experiments with artificial blood substitutes even after studies showed that the controversial products posed a clear risk of causing heart attacks and death. The review of combined data from more than 3,711 patients who participated in 16 studies testing five different types of artificial blood, released yesterday, found that the products nearly tripled the risk of heart attacks and boosted the chances of dying by 30 percent. Based on the findings, the researchers questioned why the FDA allowed additional testing of the products to go forward and why the agency is considering letting yet another study proceed. ‘It’s hard to understand,’ said Charles Natanson, a senior investigator at the National Institutes of Health who led the analysis, which was released early by the Journal of the American Medical Association so the data could be presented at an FDA meeting on the subject. ‘They already had data that these products could cause heart attacks and evidence that they could kill.’ An FDA official defended the agency, saying it had carefully weighed the risks and benefits of each study individually and had convened this week’s two-day meeting […]