By: Ed Susman

ORLANDO, FL – Patients suffering an acute myocardial infarction accumulate high levels of radiation as they undergo potentially life-saving diagnostic and therapeutic treatments, researchers reported at the American Heart Association Scientific Sessions 2009.

“We estimate that one series of tests can result in an average heart attack patient receiving 14.5 millisieverts of radiation – about 30% of what radiation workers are allowed to accumulate in a year,” explained Prashant Kaul, MD, Duke University Medical Center, Durham, North Carolina, speaking at an oral presentation.

Dr. Kaul said the level of radiation may or may not be considered high, assuming that diagnostic treatment is required urgently, and catheterisation and computed tomography scans routinely pinpoint cardiovascular problems in the acute-care setting.

“We thought we should remind doctors that ionising radiation does have a theoretical risk to the patient, and doctors might keep that in mind when ordering and performing tests that use radiation,” said Dr. Kaul.

In the first large study to examine total radiation dosage in patients having heart attacks, researchers found those admitted to academic hospitals had a cumulative effective radiation dose of 14.5 millisieverts. “It’s potentially a new way to consider radiation exposure and safety,” said Dr. Kaul. “We think physicians should not only have a greater awareness of dose accumulation from the tests they are ordering, but also understand the testing patterns they use for common diagnoses.”

In this study, Dr. Kaul and colleagues analysed data from 64,074 patients, including 23,394 women and 40,680 men who were being treated for acute myocardial infarction between 2006 and the second quarter of 2009. The data were collected from 49 academic hospitals throughout the United States that participate in the University Health System Consortium and subscribe to their resource manager database.

The researchers found that patients received 276,651 tests using ionising radiation – an average of 7 per patient. Patients averaged a total accumulation of 14.52 millisieverts during their hospital stay.

Among the 9 types of tests analysed, 83% of all patients received chest x-rays; 77% had catheter procedures; 15% underwent body computed tomography scans; and 12% had a head computed tomography. Between 1% and 6% of patients had 3 other nuclear imaging tests and chest computed tomography.

“These figures are probably conservative,” noted Robert Bonow, MD, Northwestern University School of Medicine, Chicago, Illinois, and a spokesperson for the American Heart Association. “In particularly complicated catheter or angioplasty and stent placement procedures, the radiation exposure might be considerable greater.”

Dr. Bonow added that “all physicians should avoid giving patients unnecessary radiation tests.”

Funding for this study was provided by Duke University Division of Cardiovascular Medicine.

- MFP Wire Services
- 11-20-2009