Author + information
- Abhishek Sharma, MD⁎ ()
- ↵⁎Maimonides Medical Center, 1016 50th Street, Apartment 2C, Brooklyn, New York 11219
In the ACIC (Advanced Cardiovascular Imaging Consortium) registry, Chinnaiyan et al. (1) evaluated the correlation between stress test results and extent of coronary artery disease (CAD) on coronary computed tomography angiography (CCTA) and compared the diagnostic performance of both noninvasive modalities in patients undergoing invasive coronary angiograms. The authors should be commended for their attempts to answer a pertinent debate on appropriate use of various diagnostic modalities in evaluation of CAD. However, a few interesting points arise from the analysis, and several caveats have to be considered before reaching a final conclusion.
First, authors defined obstructive CAD as coronary stenosis >50% rather than 70%, which might account for higher reported sensitivity of CCTA in the study. It has been shown that ≥70% stenosis is a better predictor of associated physiologically significant perfusion defect and has more clinical implications (2). It would be interesting to know whether the investigators have data with regard to the degree of stenoses and perfusion defect, so that more appropriate conclusions can be made before accepting the study result that stress test did not predict obstructive CAD (1). Moreover, the reported low yield of stress testing in the study can be explained on the basis of work-up bias (inclusion of patients for disease verification by a gold standard test based on the results of preliminary testing) (3).
Second, the reason why asymptomatic patients underwent invasive coronary angiography requires clarification, because there is no clear benefit of revascularization in these patients; the same also applies to patients with normal stress tests and nonobstructive CAD on CCTA.
Third, the role of CCTA in asymptomatic patients is still not established. With regard to the recommendations of the authors to use CCTA in the asymptomatic individual with cardiac risk factors instead of a stress test before surgery or beginning of a vigorous exercise program, citing low positive predictive value (PPV) of stress, it is important to note that most patients in the study the authors quote here were symptomatic and that the study also counted equivocal tests as positive while calculating PPV that lowers the reported PPV (4).
Lastly, it would also be interesting to know whether the authors made any attempt to study the impact of calcium score on the role of CCTA as “gatekeeper” to invasive coronary angiography.
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