CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Arun Abraham, MBBS,
Jimmy MacHaalany, MD and
Benjamin J.W. Chow, MD*
* University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, Ontario K1Y 4W7, Canada (Email: bchow{at}ottawaheart.ca).
We thank Drs. Bartoletti and colleagues for their interest in our study (1).
If one could operate in a world without risk and that is unconstrained by costs, all incidental findings (IFs) could be investigated. However, the investigation of IFs must be tempered by the reality that benefits may be offset by risks and costs. In this unblinded observational study, mortality was chosen as the primary outcome measure because it is least influenced by subjectivity. Although we agree that when interventions prevent or delay death the mortality in 2 groups will likely favor equivalence, it is also important to recognize that survival benefits may also be attributed to lead-time bias.
We also agree that a longer follow-up duration may have better facilitated appreciation of differences in outcomes between comparison groups, and this limitation has been acknowledged. However, none of the indeterminate IFs became clinically significant. The majority of the patients were followed up until a diagnosis was made or until no further follow-up was recommended (i.e., the IF was deemed benign). Even if inferior outcomes were noted in IF patients, further studies would be needed to explain whether the association is causal or serendipitous, given the benign disposition of IFs.
Most important is the readers' observation that more studies are needed and that a randomized controlled trial of patients with indeterminate IF would be ideal and should be encouraged. However, one must accept that randomizing patients with IFs could be seen as unethical and may not be clinically feasible at many centers. Thus, it is important that results such as ours be used to encourage discussion and to cast doubt on our current clinical practice, thus opening the opportunity for researchers to justify such randomized controlled trials.
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Footnotes
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Please note: Dr. Abraham was supported by the Heather and Whit Tucker Research Fellowship in Cardiology. Dr. Chow is supported by the CIHR New Investigator Award MSH-83718, and receives research and fellowship training support from GE Healthcare, research support from Pfizer Inc. and AstraZeneca, and educational support from TeraRecon Inc. Dr. Chow's research is supported in part by the Imaging for Cardiovascular Therapeutics Project RE02-038 and the Canada Foundation for Innovation 11966.
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References
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1. MacHaalany J, Yam Y, Ruddy TD, et al. Potential clinical and economic consequences of noncardiac incidental findings on cardiac computed tomography J Am Coll Cardiol 2009;54:1533-1541.[Abstract/Free Full Text]
Related Article
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A Closer Look at Incidental Findings on Cardiac Computed Tomography
- Stefano Bartoletti, Francesco Perna, Pasquale Santangeli, and Michela Casella
J. Am. Coll. Cardiol. 2010 55: 702-703.
[Full Text]
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