A widely used test to detect blockages in the heart's arteries often turns up little or no evidence of disease, a new study found, suggesting that patients are frequently exposed unnecessarily to the risks and costs of the invasive examination. The test is a called a coronary angiogram, in which cardiologists thread a catheter into the heart to take an X-ray movie to look for obstructions that might cause chest pain or increase the risk of a heart attack. More than a million U.S. patients undergo the diagnostic test each year at a cost of about $10,000 each, according to government data. In cases where significant obstruction is found, the test helps doctors determine whether a patient should undergo coronary bypass surgery or have a stent implanted to alleviate the problem. View Full Image Photo Researchers A cardiologist threads a catheter into the heart through a blood vessel in the groin to initiate an angiogram. Related Health Video News Hub: Why You Can Die of a Broken Heart (02/08/10) News Hub: Even Thin People Face Health Risks (01/26/10) The new study, published in this week's New England Journal of Medicine, is based on data on nearly 400,000 angiograms performed between 2004 and 2008 that 633 hospitals in the U.[Read more...]