CardioExchange Archive

CardioExchange, an NEJM practice community for medical professionals dedicated to improving cardiac patient care, was active from 2009 to 2015. CardioExchange fostered discussion between clinicians from across the globe.

May 23rd, 2011

What Is the Impact of Screening Low-Risk Patients with CT Angiography?

In a study published online in Archives of Internal Medicine, John McEvoy and colleagues examine the impact of screening low-risk patients with coronary CT angiography (CCTA). They compared 1000 South Korean patients who underwent CCTA with 1000 matched controls.

CCTA identified 215 people with coronary atherosclerosis. At 90 days and at 18 months, statins and aspirin were being taken by a significantly higher percentage of patients in the CCTA-positive group than in the CCTA-negative group or in the matched control group:

At 90 days

  • statins were used in 34% of CCTA-positive patients vs. 5% of CCTA-negative patients and 8% of those in the control group
  • aspirin was used in 40% vs. 5% and 8%

At 18 months

  • statins were used in 20% vs. 3% and 6%
  • aspirin was used in 26% vs. 3% and 6%

The investigators also found that, at 90 days, there were more secondary tests and revascularizations in the CCTA group than in the control group:

  • secondary tests: 5% vs. 2%, p<0.001
  • revascularizations: 1% vs. 0.1%, p<0.001

At 18 months there was one cardiovascular event in each group.

The authors observed that in their study “we found that the evidence-free performance of CCTA in asymptomatic patients was associated with further evidence-free testing and interventions.” They concluded that their data “concurs with the prevailing notion that screening CCTA does not have a role in low-risk patients.”

In an invited commentary, Michael Lauer said the study “serves as a powerful reminder of the 2-edged effects of screening.” He continues:

“The only way to know whether screening by CCTA leads to clinically beneficial diagnosis of real disease, as opposed to pseudodisease, is by performing large-scale controlled trials, preferably with randomization. We cannot simply assume that just because a screening test predicts clinical outcomes, interventions necessarily will prevent them. Similarly, we cannot assume that because other tests diagnose disease that responds to treatment, a new screening test must do the same.”

 

 

Categories: Cardiac Imaging, General
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2 Responses to “What Is the Impact of Screening Low-Risk Patients with CT Angiography?”

  1. Richard Kones, MD PhD says:
    May 23, 2011 at 10:20 pm

    Screening, like all preventive measures, is a function of the population studied, the screen technique, and target disease, which cannot be generalized. Applied to this report, it suggests CCTA screening is unproductive under the study conditions. No physician cares for pseudodiseases and unproductive witch hunts.

    First, if all screening were limited to RCT outcome studies, many changes would be required which might severely impair patient care. Second, this should not cast doubt about screening generally. It just needs to be very selective.

    Use of Framingham Risk Scores has never been shown to improve outcomes, yet it enjoys widespread use, is time-tested, and is recommended in the latest ACCF/AHA guidelines to be used in all adults.

    On the other hand, JUPITER provided unique RCT data with significant implications. Yet it was brutally attacked because of limitations which were perhaps over-emphasized.

    Calcium scores, also popular, and certainly valuable in predicting CHD events, have never been shown to improve outcomes in a large RCT. Eliminating use of calcium scores until this was completed would likely disrupt usual and customary patient care.

    Identifying high risk individuals for primary prevention of CHD using EBM is tough.
    Richard Kones

  2. Jean-Pierre Usdin, MD says:
    May 26, 2011 at 12:11 am

    In fact in this low-risk patients population the number of revascularizations was very low (Number Needed to Evaluate: 50 for 1 revascularization)as the risk score predicted without semi invasive test (considering radiation effect and Iodin injection)

    Furthermore patients not tested took more preventive treatment -Aspirin and Statin- than patients in the negatively tested group.
    May be (but the sample is too small) this cohort (not tested) was best protected without knowledge of their anatomic coronary arteries status!

    This my indicate that clinical good sense in a low risk population is better than non necessary tests.

    Competing interests pertaining specifically to this post, comment, or both:
    none