Author + information
- Kavitha M. Chinnaiyan, MD⁎ ()
- ↵⁎William Beaumont Hospital, 3601 West 13 Mile Road, Royal Oak, Michigan 48073
Dr. Sharma conveys reasonable concerns with regard to our findings from the ACIC (Advanced Cardiovascular Imaging Consortium) registry (1). We agree that using a cutoff of >50% stenosis rather than >70% stenosis is a limitation of this study, as clarified in the paper. Stress tests in this study were varied and consisted of 3 different modalities that have varied strengths and limitations. For example, although stress echocardiography performs best to detect ischemia in territories with hemodynamically significant (>70%) stenosis, numerous studies have also assessed the accuracy of this modality for using an angiographic stenosis cutoff of ≥50% as significant (2). Due to its ability to detect flow heterogeneity because of impairment of flow reserve (rather than ischemia), nuclear imaging can “pick up” <70% stenosis (3). Hence, a cutoff of >50% in this “mixed bag” of stress tests might not be unreasonable.
With respect to accuracy, our findings reflect the limitations of comparing anatomic versus functional imaging, which have previously been demonstrated as well (4,5). Reassessment of accuracy with >50% and >70% stenosis is presented in Table 1. Although there are minor differences in accuracy between the two degrees of stenoses, it continues to be lower than previously reported.
We also agree that asymptomatic patients have not been shown to benefit from invasive coronary angiography (ICA) or revascularization. As stated in the paper, these results represent “real world” practice. All management decisions in ACIC remain at the discretion of physicians referring these patients to CCTA. Some patients might have had a stress test for screening purposes that were abnormal or questionable, leading to a CCTA for adjudication. The appropriateness of upstream stress testing or downstream ICA or revascularization in asymptomatic individuals remains questionable, and this was beyond the scope of this study. We agree that the role of CCTA in asymptomatic patients is still not established, and as discussed in the paper, CCTA is an effective tool to adjudicate stress test findings, not an alternative to stress tests or no testing in such individuals.
Last, the role of calcium scores as a “gatekeeping” function to ICA was not assessed in this study.
- American College of Cardiology Foundation
- Chinnaiyan K.M.,
- Raff G.L.,
- Goraya T.,
- et al.
- Feigenbaum H.,
- Armstrong W.,
- Ryan T.