Acute heart attack patients admitted to academic hospitals average a cumulative effective radiation dose of 14.52 mSv from imaging and other procedures. Researchers cautioned physicians to be aware of the cumulative effect of all ionizing radiation tests, rather than just focusing on the dose of each exam. The study was presented at the 2009 American Heart Association (AHA) meeting in Orlando, Fla., on Monday.
The study, presented by Prashant Kaul, MD, a fellow in cardiovascular medicine at Duke University Medical Center in Durham, N.C., found that the combined dose of ionizing radiation received annually from medical testing increased by 700 percent between 1980 and 2006, with one-third of the testing being conducted on cardiovascular patients.
The study included 64,074 patients—23,394 women and 40,680 men—treated for acute heart attacks between 2006 and 2009 at various academic hospitals in the U.S. Researchers determined that an average of seven tests using ionizing radiation were performed on each patient during his or her hospital stay.
The study also found that of the nine types of tests evaluated, 83 percent of all patients received chest x-rays; 77 percent had catheter procedures; 15 percent had CT scans; and 12 percent underwent a head CT. In addition, 1 to 6 percent of all patients had nuclear imaging tests and chest CT.
Kaul suggested that physicians are primarily concerned with the radiation dose a patient will receive with each test, rather than the total radiation level that a patient will undergo throughout his or her hospital stay.
Despite these concerns, Kaul stressed the significance of imaging testing.
"We should not withhold necessary, appropriate tests that involve ionizing radiation—they provide very important information," said Kaul. "What we should do is evaluate and understand the clinical indications for tests that involve ionizing radiation. We need to be sure they are being done appropriately."
The researchers in this study focused on nine tests used for assessing heart attacks, but physicians may use others. Further limitations of the study included the reported cumulative and radiation dose per patient as an estimate rather than actual measurement, as the researchers used estimates of typical effective radiation doses from several sources.