CT Angiography Detects More Pulmonary Emboli but Death Rates Unchanged

July 3, 2013

Many more pulmonary emboli are being detected since the introduction of CT angiography, but the death rate has not decreased.

More pulmonary emboli are now detected with CT pulmonary angiography, but death rates from the emboli remain unchanged, according to a study published in the BMJ.

There has been an 80 percent rise in the detection of pulmonary embolism between 1998 and 2006, since the introduction of CT pulmonary angiography. CT angiography is more sensitive than ventilation-perfusion (VQ) scanning so it detects more emboli (from 62.1/100, 000 to 112.3/100, 000).

However, despite the increase in detection, there has not been a reduction in deaths. Using national U.S. data, the researchers found that death from pulmonary embolism in the U.S. population moved only slightly from 12.3 per 100,000 to 11.9 per 100,000, while in-hospital deaths decreased by a third, from 12.1 percent to 7.8 percent. These findings suggest that the extra emboli that are being detected are not clinically important.

The researchers pointed out that overdiagnosis of pulmonary embolism leads to anxiety and fear for the patients, as well as overtreatment that can result in complications from the anti-clotting medications.

While these findings are important, limiting testing is not a realistic option, noted the researchers. Instead, they suggest that clinicians be more selective about their testing and treatment and that alternative tests, such as VQ scanning and ultrasounds, be used when appropriate.

The authors concluded that while CT pulmonary angiography has been helpful in finding more emboli, researchers still need to determine which of the smaller emboli require treatment, thereby avoiding overtreatment of patients.