“It is the framework which changes with each new technology and not just the picture within the frame,” Marshall McLuhan, Canadian communications theorist, educator, writer and social reformer, once said. Like upcoming technologies, particularly in the medical imaging world, clinical and scientific research must prove a modality's clinical effectiveness. A recent Radiology study found that 20 to 50 percent of advanced imaging procedures could be unnecessary, but mounting evidence also suggests that imaging modalities such as PET and SPECT, CT angiography (CTA) and cardiac MRI are beneficial. Interspersed between the two extremes is the appropriate use of guidelines to inform imaging decisions.
This week, a JACC study showed that cardiac MR can successfully predict risk of cardiovascular events in patients who have frequent premature ventricular complexes.
Additionally, researchers from the University of Heidelberg, Germany, found that high-dose dobutamine stress MRI (DS-MRI) can more accurately identify patients who may be at a high risk for cardiac death and heart attack.
The JACC study found that those with wall motion abnormalities (WMAs) and perfusion deficits had a higher risk of cardiac death, heart attack or revascularization. Results showed that patients with inducible WMA were 33 percent more likely to experience CV events and 40 percent more likely to undergo revascularization, while patients with normal DS-MRI readings had low CV events and revascularization.
Data have emerged from this year’s ASNC meeting showing that while SPECT and PET have prognostic value, CTA may trump the other two modalities in low and high-risk patient stratification.
Additionally at the meeting, data showed that educating physicians about appropriate use criteria for ordering SPECT myocardial perfusion imaging can reduce inappropriate tests in patients who are not asymptomatic.
After educating physicians on appropriate use criteria, researchers found that inappropriate SPECT referrals declined over 30 percent from pre- to post-intervention periods. Meanwhile, appropriate referrals for preoperative evaluation in intermediate-risk patients with poor function and those at high-risk surged by 30 percent, proving that education may change ordering habits for the better.
Lastly, a s tudy this week in JACC showed that over 50 percent of patients had at least one stress test performed post-revascularization, but only 5 percent required repeat revascularization. These results allude to the fact that stress testing may be overutilized and must be redefined in this patient population.
As physicians struggle to understand what cardiac imaging modalities may be best to depict risk of adverse events, guidelines and education of appropriate use must be filtered into practice to avoid scrutiny of cardiologists regarding imaging overutilization. A better focus on the reduction of imaging testing would enhance patient care while at the same time cut costs.
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