Correspondence Twenty-four-hour aortic ambulatory blood pressure monitoring and target organ damage: more data are needed Athanase D. Protogerou a, James E. Sharman b, Siegfried Wassertheurer c, and Thomas Weber d
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e read with interest the article by de la Sierra et al. [1] which concluded that 24-h aortic average systolic and/or pulse pressure (PP) do not correlate more strongly with a composite endpoint of target organ damage compared with 24-h brachial blood pressure (BP). The results of this study are not in line with five previous publications derived from two different cohorts performed in Greece [2–4], Australia [5] and one multicenter study from seven centers in Europe [6], which included overall more than 800 individuals. These five publications replicated the same result, that is that either 24-h [2–4,6] or static [2,5] aortic SBP was better associated with (or detected abnormalities in) left ventricular (LV) structure and/or function, than the corresponding 24-h and/or static brachial BP (BP). Of note, all studies [1–6] used the same ambulatory device (Mobil-O-Graph: IEM, Stolberg, Germany) to assess aortic and brachial BP. We were interested in understanding the factors that might explain the findings provided by de la Sierra et al. [1]; some potential factors are discussed below. First, the authors used a combined endpoint of target organ damage that included renal dysfunction, LV hypertrophy and aortic stiffness (the latter assessed by Mobil-OGraph device). A large meta-analysis based on static BP measurements has shown that renal function was not better associated with aortic than brachial BP, possibly due to fact that renal artery is relatively remote from the ascending aorta. It would be of interest if the authors were to provide analysis of the data separately for each type of organ damage. Second, the cutoff of 10 m/s used by the authors to define organ damage of the aorta is applicable only to carotid–femoral pulse wave velocity, leading to potential misclassification of the population. Third, in all five previous publications [2–6], aortic SBP derived with the mean/DBP calibration performed better than the aortic BP derived by the SBP/DBP calibration. This is explained by the mean/diastolic calibration method providing more accurate estimation of the intra-arterial aortic SBP using the Mobil-O-Graph device. The authors reported in the supplement of the article that they have used the mean/diastolic calibration without substantial differences compared with the SBP/DBP calibration regarding their association with the composite endpoint. However, this point deserves further clarification and data regarding the association of each mode of
Journal of Hypertension
calibration with each biomarker of organ damage would be very helpful to present. Finally, it is important to clarify the explanation provided on the derivation of negative PP amplification when the mean/diastolic calibration method is used. Readers should be aware that this phenomenon is due to the inaccuracy (underestimation) of the noninvasive brachial SBP measurement by the oscillometric measurement and not due to errors introduced by the mean/diastolic calibration mode. To provide more definitive answers on many issues, including those mentioned above, we have initiated an academic research consortium on 24-h pulsatile hemodynamics; already comprising 20 centers worldwide. Participation is still open to all interested researchers.
ACKNOWLEDGEMENTS Conflicts of interest There are no conflicts of interest.
REFERENCES 1. de la Sierra A, Pareja J, Ferna´ndez-Llama P, Armario P, Yun S, Acosta E, et al. Twenty-four-hour central blood pressure is not better associated with hypertensive target organ damage than 24-h peripheral blood pressure. J Hypertens 2017; [Epub ahead of print]. 2. Protogerou AD, Argyris AA, Papaioannou TG, Kollias GE, Konstantonis GD, Nasothimiou E, et al. Left-ventricular hypertrophy is associated better with 24-h aortic pressure than 24-h brachial pressure in hypertensive patients: the SAFAR study. J Hypertens 2014; 32:1805–1814. 3. Zhang Y, Kollias G, Argyris AA, Papaioannou TG, Tountas C, Konstantonis GD, et al. Association of left ventricular diastolic dysfunction with 24-h aortic ambulatory BP: the SAFAR study. J Hum Hypertens 2015; 29:442–448. 4. Chi C, Yu SK, Auckle R, Argyris AA, Nasothimiou E, Tountas C, et al. Association of left ventricular structural and functional abnormalities with aortic and brachial blood pressure variability in hypertensive patients: the SAFAR study. J Hum Hypertens 2017; [Epub ahead of print]. 5. Negishi K, Yang H, Wang Y, Nolan MT, Negishi T, Pathan F, et al. Importance of calibration method in central BP for cardiac structural abnormalities. Am J Hypertens 2016; 29:1070–1076. 6. Weber T, Wassertheurer S, Sala ER, Ablasser C, Jankowski P, Muisan ML, et al. OS 130-09. Relationship between 24 h ambulatory central BP and left ventricular mass – a retrospective multicenter study. J Hypertens (34 Suppl 1 – ISH 2016 Abstract Book):2016;e210–e211. Journal of Hypertension 2017, 35:2323–2330 a Cardiovasular Prevention and Research Unit, Department of Pathophysiology, LAIKO Hospital, National and Kapodistrian University of Athens, Athens, Greece, bMenzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia, c Health & Environment Department, Austrian Institute of Technology, Vienna and d Cardiology Department, Klinikum Wels-Grieskirchen, Wels, Austria
Correspondence to Athanase D. Protogerou, Associate Professor, Cardiovascular Prevention & Research Unit, Department of Pathophysiology, Medical School, National and Kapodistrian University of Athens, 75, Mikras Asias Street (Building 16–3rd floor), 115 27 Athens, Greece. Tel: +0030 210 7462566; fax: +0030 210 7462566; e-mail: [email protected] J Hypertens 35:2323–2330 Copyright ß 2017 Wolters Kluwer Health, Inc. All rights reserved. DOI:10.1097/HJH.0000000000001544
www.jhypertension.com
Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.
2323
W
e read with interest the article by de la Sierra et al. [1] which concluded that 24-h aortic average systolic and/or pulse pressure (PP) do not correlate more strongly with a composite endpoint of target organ damage compared with 24-h brachial blood pressure (BP). The results of this study are not in line with five previous publications derived from two different cohorts performed in Greece [2–4], Australia [5] and one multicenter study from seven centers in Europe [6], which included overall more than 800 individuals. These five publications replicated the same result, that is that either 24-h [2–4,6] or static [2,5] aortic SBP was better associated with (or detected abnormalities in) left ventricular (LV) structure and/or function, than the corresponding 24-h and/or static brachial BP (BP). Of note, all studies [1–6] used the same ambulatory device (Mobil-O-Graph: IEM, Stolberg, Germany) to assess aortic and brachial BP. We were interested in understanding the factors that might explain the findings provided by de la Sierra et al. [1]; some potential factors are discussed below. First, the authors used a combined endpoint of target organ damage that included renal dysfunction, LV hypertrophy and aortic stiffness (the latter assessed by Mobil-OGraph device). A large meta-analysis based on static BP measurements has shown that renal function was not better associated with aortic than brachial BP, possibly due to fact that renal artery is relatively remote from the ascending aorta. It would be of interest if the authors were to provide analysis of the data separately for each type of organ damage. Second, the cutoff of 10 m/s used by the authors to define organ damage of the aorta is applicable only to carotid–femoral pulse wave velocity, leading to potential misclassification of the population. Third, in all five previous publications [2–6], aortic SBP derived with the mean/DBP calibration performed better than the aortic BP derived by the SBP/DBP calibration. This is explained by the mean/diastolic calibration method providing more accurate estimation of the intra-arterial aortic SBP using the Mobil-O-Graph device. The authors reported in the supplement of the article that they have used the mean/diastolic calibration without substantial differences compared with the SBP/DBP calibration regarding their association with the composite endpoint. However, this point deserves further clarification and data regarding the association of each mode of
Journal of Hypertension
calibration with each biomarker of organ damage would be very helpful to present. Finally, it is important to clarify the explanation provided on the derivation of negative PP amplification when the mean/diastolic calibration method is used. Readers should be aware that this phenomenon is due to the inaccuracy (underestimation) of the noninvasive brachial SBP measurement by the oscillometric measurement and not due to errors introduced by the mean/diastolic calibration mode. To provide more definitive answers on many issues, including those mentioned above, we have initiated an academic research consortium on 24-h pulsatile hemodynamics; already comprising 20 centers worldwide. Participation is still open to all interested researchers.
ACKNOWLEDGEMENTS Conflicts of interest There are no conflicts of interest.
REFERENCES 1. de la Sierra A, Pareja J, Ferna´ndez-Llama P, Armario P, Yun S, Acosta E, et al. Twenty-four-hour central blood pressure is not better associated with hypertensive target organ damage than 24-h peripheral blood pressure. J Hypertens 2017; [Epub ahead of print]. 2. Protogerou AD, Argyris AA, Papaioannou TG, Kollias GE, Konstantonis GD, Nasothimiou E, et al. Left-ventricular hypertrophy is associated better with 24-h aortic pressure than 24-h brachial pressure in hypertensive patients: the SAFAR study. J Hypertens 2014; 32:1805–1814. 3. Zhang Y, Kollias G, Argyris AA, Papaioannou TG, Tountas C, Konstantonis GD, et al. Association of left ventricular diastolic dysfunction with 24-h aortic ambulatory BP: the SAFAR study. J Hum Hypertens 2015; 29:442–448. 4. Chi C, Yu SK, Auckle R, Argyris AA, Nasothimiou E, Tountas C, et al. Association of left ventricular structural and functional abnormalities with aortic and brachial blood pressure variability in hypertensive patients: the SAFAR study. J Hum Hypertens 2017; [Epub ahead of print]. 5. Negishi K, Yang H, Wang Y, Nolan MT, Negishi T, Pathan F, et al. Importance of calibration method in central BP for cardiac structural abnormalities. Am J Hypertens 2016; 29:1070–1076. 6. Weber T, Wassertheurer S, Sala ER, Ablasser C, Jankowski P, Muisan ML, et al. OS 130-09. Relationship between 24 h ambulatory central BP and left ventricular mass – a retrospective multicenter study. J Hypertens (34 Suppl 1 – ISH 2016 Abstract Book):2016;e210–e211. Journal of Hypertension 2017, 35:2323–2330 a Cardiovasular Prevention and Research Unit, Department of Pathophysiology, LAIKO Hospital, National and Kapodistrian University of Athens, Athens, Greece, bMenzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia, c Health & Environment Department, Austrian Institute of Technology, Vienna and d Cardiology Department, Klinikum Wels-Grieskirchen, Wels, Austria
Correspondence to Athanase D. Protogerou, Associate Professor, Cardiovascular Prevention & Research Unit, Department of Pathophysiology, Medical School, National and Kapodistrian University of Athens, 75, Mikras Asias Street (Building 16–3rd floor), 115 27 Athens, Greece. Tel: +0030 210 7462566; fax: +0030 210 7462566; e-mail: [email protected] J Hypertens 35:2323–2330 Copyright ß 2017 Wolters Kluwer Health, Inc. All rights reserved. DOI:10.1097/HJH.0000000000001544
www.jhypertension.com
Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.
2323
