Reply to 'Relationship between aortic root size and glomerular filtration rate in hypertensive patients'

We are grateful to Dr Zhao Li and coauthors [1] for their interest in our work [2] and we appreciate the opportunity to comment some issues raised in their letter, a part of which have been already addressed in the discussion section of our article.They assessed the relationship between glomerular filtration rate (GFR), estimated by the chronic kidney disease (CKD)-Epidemiology Collaboration equation, and the aortic annular diameter measured from trailing edge to leading edge at the hinging points of the aortic cusps to the annulus in a general population of 5538 Chinese hypertensive patients [3]. At variance with our findings, no association was detected between GFR and aortic annular diameter, regardless of the method of indexation adopted to normalize it [3]. However, many differences between our study and that of Li et al.[3] need to be highlighted. It is likely that these differences may help to explain the seemingly discrepant conclusions between the two studies.First of all, in the study of Li et al.[3] aortic root was determined at the annulus level by two-dimensional echocardiography, whereas we measured aortic root size at the level of Valsalva's sinuses by M-mode tracings [2]. It is important to note that previous investigations documented that the correlates of aortic root may differ if its measurement is taken at different sites [4,5].Furthermore, it should be underlined, that available evidence about the clinical significance and prognostic value of aortic root size is mostly based on aortic M-mode measurements at the widest point of Valsalva's sinuses [6–8], such as in our study.Another methodological aspect of the work of Li et al.[3] deserves to be remarked. They estimated the GFR by using the CKD-Epidemiology Collaboration equation that in its original version includes only a two-level variable for race (black and whites) [9]. This equation provides a less accurate estimate of GFR in Asian people than in black and white patients. Therefore, a four-level ethnicity equation, including a coefficient for Asian populations, has been developed, thus significantly improving its performance, particularly in Chinese individuals [10].Moreover, in agreement with Li et al.[3], we believe that the much lower prevalence of CKD in their study participants, when compared with ours and the different races may be other important potential reasons of the inconsistent results of the two studies.Finally, it is noteworthy that some studies [11,12] reported an association between renal insufficiency and risk of developing abdominal aortic aneurysms. Although this evidence is not available to date for thoracic aorta, it seems to be in line with our findings and corroborate the notion that the unfavourable impact of an impaired renal function on the cardiovascular system may be extended also to the structure of the aorta. Back to Top | Article Outline ACKNOWLEDGEMENTS Funding: This work was supported by a grant from the Italian Ministry for University and Scientific Research. Back to Top | Article Outline Conflicts of interest There are no conflicts of interest. Back to Top | Article Outline REFERENCES 1. Li Z, Guo X, Sun Y. Relationship between aortic root size and glomerular filtration rate in hypertensive patient. J Hypertens 2016; 34:1232–1233. Cited Here... 2. Mulé G, Nardi E, Morreale M, D’Amico S, Foraci AC, Nardi C, et al. Relationship between aortic root size and glomerular filtration rate in hypertensive patients. J Hypertens 2016; 34:495–505. Cited Here... 3. Li Z, Guo X, Sun Y. 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