Author + information
- Sang-Eun Lee, MD, PhD and
- Hyuk-Jae Chang, MD, PhD∗ ()
- ↵∗Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Yonsei University Health System, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea
We thank Drs. Gill and Garcia-Garcia for their interest in our paper (1). Drs. Gill and Garcia-Garcia are concerned about 1) the lack of correlation between the percentage of diameter stenosis severity (13.6%) and the percentage of atheroma volume (PAV) (13.3%) at baseline in our data based on the Glagov phenomenon and 2) that previous clinical trials have reported baseline PAV as close to 40% and lesser annual change in PAV. However, these prior trials mostly represented a high-risk population indicated for invasive assessment, and consequently, both the PAV and stenosis severity were much greater than lesions included in our study (2). The PARADIGM (Progression of Atherosclerotic Plaque Determined by Computed Tomographic Angiography Imaging) registry was designed to represent the patients at low risk or at an earlier stage of coronary artery disease, who would possess much lower PAV than patients in previous studies would. This difference in study population makes the direct comparison of PAV between the present study and previous clinical trials inappropriate. Furthermore, what the Glagov phenomenon acknowledges is that “functionally” important luminal stenosis may be delayed until the lesion occupies 40% of the internal elastic lamina area and the development of positive remodeling during the course (3). It is difficult to agree that the lesions with mean diameter stenosis of 13% are functionally important and therefore should correspond with PAV much >40%. In our study, only 1.6% of lesions had ≥50% diameter stenosis, and positive remodeling was observed in 53.5% of lesions at baseline. The result of our study supports the findings of previous studies rather than conflicting with them.
We certainly acknowledge Drs. Gill and Garcia-Garcia’s concern about the revascularized lesions in the interscan interval and agree that inclusion of revascularized lesions in the interscan interval may have further confounded the results. We excluded “patients” who revascularized during the interscan interval, and hence all of their lesions, from the analysis because the revascularization occurred prior to the follow-up coronary computed tomography angiography scan due to the observational nature of the study. This design makes inadequate the direct comparison of the number of interscan revascularizations (which occurred in patients and their lesions already excluded from the analysis) with the reported rate of high-risk plaque progression and number of “lesions” with diameter stenosis ≥50% at follow-up. The lesions revascularized prior to the appointed follow-up imaging were also excluded in prior clinical trials (2).
We have described the limitation of our study with respect to the lack of information regarding statin duration and intensity, and the data for absolute plaque volumes have been excluded because we agreed that reporting the results in PAV format would better correspond with results from previous invasive imaging published reports. To address these limitations, our group is currently conducting a prospective clinical trial (ACROSS [Assessment of Change in Atherosclerotic Plaque by Serial CCTA]; NCT03414840).
Please note: This work was supported by the Leading Foreign Research Institute Recruitment Program through the National Research Foundation of Korea funded by the Ministry of Science and Information and Communications Technology (grant no. 2012027176). The study was also funded in part by a generous gift from the Dalio Institute of Cardiovascular Imaging and the Michael Wolk Foundation. The funders of the study had no role in the study design; data collection, analysis, or interpretation; or writing of the report. The corresponding author had full access to all the data for the study and had final responsibility for the decision to submit the manuscript for publication.
- 2018 American College of Cardiology Foundation
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