Return to Main Menu

Findings by MU faculty published in JAMA Physicians can minimize radiation exposure, avoid an invasive procedure and reduce health care costs by relying on a spiral CT scan in cases of suspected pulmonary embolism, according to a study in the April 27 issue of the Journal of the American Medical Association (JAMA).   U. Joseph Schoepf, M.D., associate professor of radiology, is the study’s lead author. Philip Costello, M.D., professor and chairman, MUSC Department of Radiology is among the other authors.    A pulmonary embolism is an obstruction of an artery in the lung, usually caused by blood clots.  The clots frequently originate in the legs, but could come from other parts of the body. A pulmonary embolism can cause death or permanent damage to the heart and lungs, but can be treated with anti-coagulating medication. Each year, more than 600,000 in the United States suffer a pulmonary embolism. It is the third most common cardiovascular cause of death after heart attacks and strokes.   Risk factors for pulmonary embolism include inactivity for long periods of time, surgery, stroke, heart attack, congestive heart failure and leg fractures.   Pulmonary angiography was the gold standard for diagnosing a pulmonary embolism. This requires inserting a catheter into a blood vessel of the thigh or arm and then guiding it to the pulmonary artery. An iodine-containing dye is injected into the artery, making it more visible by an X-ray. While the risks associated with pulmonary angiography are small, they include the possibility of catheter damage to a vein or dislodgment of clotted blood from the vein wall.   The JAMA article points out that the spiral CT, a simpler, less invasive test is readily available in most hospitals and is rapidly becoming the first-line imaging test for assessing patients with suspected acute pulmonary embolism. But many patients with negative spiral CT studies receive additional imaging tests for definitive exclusion, increasing radiation exposure, risks of complication as well as increasing costs.    In order to determine if spiral CT was an appropriate test for  ruling out clinically significant pulmonary embolisms, Costello, Schoepf and their co-investigators determined the rate of a subsequent pulmonary embolism after anticoagulation was withheld as a result of a negative chest spiral CT study.   The investigators analyzed data from 3,500 patients who participated in 15 studies with patient follow-up ranging from three to 12 months. The conclusion reached from data analysis was that the clinical validity of chest CT to rule out pulmonary embolism is similar to that reported for conventional angiography.   “We concluded, therefore, that withholding anticoagulation medication after a negative spiral CT appears to be safe and additional imaging for excluding pulmonary embolism is ordinarily not warranted,” said Schoepf.   “This is exactly the type of outcome data we needed to gain trust in spiral CT as a test that can rule out the disease, said John Heffner, M.D., an MUSC pulmonary and critical care physician. “We knew that a positive study provided reliable confirmation of the presence of a clot. Negative studies, however, were less clear in meaning. Now we know that patients with negative studies do not return with complications of a ‘missed diagnosis’”     Friday, April 29, 2005 Catalyst Online is published weekly, updated as needed and improved from time to time by the MUSC Office of Public Relations for the faculty, employees and students of the Medical University of South Carolina. Catalyst Online editor, Kim Draughn, can be reached at 792-4107 or by email, catalyst@musc.edu. Editorial copy can be submitted to Catalyst Online and to The Catalyst in print by fax, 792-6723, or by email to petersnd@musc.edu or catalyst@musc.edu. To place an ad in The Catalyst hardcopy, call Community Press at 849-1778.