New research indicates that a diagnostic strategy using computed tomographic pulmonary angiography (CTPA) may be a safe alternative to conventional lungs scans (known as ventilation-perfusion scans) for excluding the diagnosis of pulmonary embolism (blood clots in the lung vessels), although CTPA may detect more clots, according to a study in the current issue of JAMA: The Journal of the American Medical Association.
Pulmonary embolism is a common and serious medical condition leading to the hospitalization or death of more than 250,000 people in the U.S. each year, and is estimated to result in 5 percent to 10 percent of all deaths in U.S. hospitals. Pulmonary embolism remains one of the most difficult conditions for clinicians to diagnose accurately, with timely, accurate tests essential to start appropriate therapy, while avoiding the risks of therapy to patients diagnosed as not having a pulmonary embolism, according to background information in the article.
For 30 years, ventilation-perfusion (V/Q) lung scanning had been the non-invasive imaging procedure of choice in patients with suspected pulmonary embolism. In the last decade, CTPA was introduced as an alternative non-invasive test and has been adopted rapidly, despite some concerns about the sensitivity (the proportion of affected individuals who have a positive test result for a condition the test is intended to reveal) of this method.
David R. Anderson, M.D., of Dalhousie University, Halifax, Nova Scotia, Canada, and colleagues conducted a comparison of CTPA with V/Q scanning to determine if CTPA is a safe, reliable alternative to V/Q scanning, and does not miss the detection of clinically important pulmonary blockages. The trial was conducted at four Canadian and one U.S. tertiary care centers between May 2001 and April 2005 and included 1,417 patients considered likely to have acute pulmonary embolism. Patients were randomized to undergo either V/Q scanning (n = 716) or CTPA (n = 701). Patients in whom this testing did not indicate pulmonary embolism did not receive anti-thrombotic therapy and were followed-up for three months.