The A,B,C's of CT
Here is the good news. This week CT was found to trump 2D echo for valve replacement. Researchers from Cedars-Sinai Heart Institute in Los Angeles found that 3D CT could become the new gold standard for aortic annular evaluation prior to transcatheter aortic valve replacement (TAVR). The results showed that CT imaging would have reassigned 45 percent of patients undergoing transesophageal echocardiography (TEE) to a different size Sapien valve (Edwards Lifesciences).
Similarly, researchers from St. Paul’s Hospital, University of British Columbia in Vancouver, found that 3D aortic annular dimensions obtained with CT were predictive of valve leakage post-TAVR. During the study, paravalvular aortic regurgitation (PAR) was found to be associated with transcatheter heart valve (THV) undersizing and the difference between THV sizes and multidetector CT annular size predicted PAR. While the authors did not suggest that CT is superior to TEE, they said that it could be an add-on that provided additional and complementary information for patients undergoing TAVR.
But with the good, usually comes some bad. This week, CT also received some flak. With CT, radiation exposure is always a significant concern. And while most are working fiercely to reduce the amount of radiation to which patients are exposed, a study in the February issue of Emergency Medicine Australasia showed that whole-body panscanning protocols for CT for patients who experienced blunt trauma raised the number of patients exposed to 20 mSv of radiation or more by 8 percent. A setback perhaps for all the hard work put into delivering doses that are as low as reasonably achievable.
But while the increased dose may be concerning, the authors said that before the introduction of the protocol, there were six patients with missed head, neck or torso injuries. Additionally, they said that other benefits of the protocol included a reduced need for admission, reduced hospital stay and reduced costs.
In medicine, you must take the good with the bad. While CT may emit radiation, its ability to find internal trauma, narrowed arteries or blockages, among others, is indispensable. How has CT helped you? Write me and let me know.
Cardiovascular Business, associate editor