Correspondence

Ambulatory Blood-Pressure Monitoring

N Engl J Med 2006; 355:850-851August 24, 2006

Article

To the Editor:

Variability of blood pressure is increasingly being recognized as having a predictive value in clinical outcomes independently of the 24-hour average measurement, as in the review article by Pickering and colleagues (June 1 issue).1 Whereas dipping patterns have been considered as a measure of blood-pressure variability, a classification system based on the phase and amplitude of the human circadian rhythm, interpreted in the light of reference values for sex and age,2 offers superior discrimination. In a six-year prospective study involving 297 patients with no history of morbid cardiovascular events who were undergoing 48-hour ambulatory blood-pressure monitoring,3,4 a circadian amplitude above the upper 95 percent prediction limit in clinically healthy persons peer-matched according to sex and age showed a relative risk of 4.27 (95 percent confidence interval, 2.43 to 7.51; P<0.001), whereas a nondipping pattern of blood pressure was not discriminatory (relative risk, 1.37; 95 percent confidence interval, 0.75 to 2.51; P>0.05). New analyses involving 1179 untreated patients5 indicate that the left ventricular mass index is elevated in patients with an abnormal circadian pattern of diastolic blood pressure (F=15.959, P<0.001), as compared with those who have a pattern of nondipping, reverse dipping, or extreme dipping (F=1.605, P=0.186).

Germaine Cornélissen, Ph.D.
University of Minnesota, Minneapolis, MN 55455
corne001@umn.edu

Chen-Huan Chen, M.D.
National Yang-Ming University, Taipei 112, Taiwan

Franz Halberg, M.D.
University of Minnesota, Minneapolis, MN 55455

5 References

1. 1

   Pickering TG, Shimbo D, Haas D. Ambulatory blood pressure monitoring. N Engl J Med 2006;354:2368-2374
   Full Text | Web of Science | Medline

2. 2

   Cornelissen G, Schwartzkopff O, Halberg F, Otsuka K, Watanabe Y. 7-Day ambulatory monitoring for adults with hypertension and diabetes. Am J Kidney Dis 2001;37:878-878
   CrossRef | Web of Science | Medline

3. 3

   Otsuka K, Cornelissen G, Halberg F. Predictive value of blood pressure dipping and swinging with regard to vascular disease risk. Clin Drug Invest 1996;11:20-31
   CrossRef | Web of Science

4. 4

   Otsuka K, Cornelissen G, Halberg F, Oehlert G. Excessive circadian amplitude of blood pressure increases risk of ischemic stroke and nephropathy. J Med Eng Technol 1997;21:23-30
   CrossRef | Web of Science | Medline

5. 5

   Chen CH, Ting CT, Lin SJ, et al. Relation between diurnal variation of blood pressure and left ventricular mass in a Chinese population. Am J Cardiol 1995;75:1239-1243
   CrossRef | Web of Science | Medline

Author/Editor Response

How diurnal changes in blood pressure should best be described has been debated for many years. The mesor (midline estimating statistic of rhythm) method favored by Cornélissen et al. assumes that there is an intrinsic sinusoidal circadian rhythm, whereas the dipping classification system makes no such assumption. The consensus is that the major source of the changes is the cycle of sleep, wakefulness, and activity, which favors an analysis based on the waking–sleeping difference (dipping). Clearly, however, the two methods should give overlapping results, since patients who have a nondipping pattern will have a low amplitude according to the mesor method. The finding by Otsuka et al.1 that excessive diurnal changes in blood pressure predict nephropathy as well as ischemic strokes is at variance with other published studies.2 The literature on the role of the diurnal rhythm of blood pressure in predicting stroke is mixed: one Japanese study found that patients with an exaggerated morning surge are at increased risk for strokes,3 whereas another study found that this applied only to hemorrhagic strokes and that ischemic strokes were more common in patients with a nondipping pattern.4

Thomas G. Pickering, M.D., D.Phil.
Daichi Shimbo, M.D.
Columbia Presbyterian Medical Center, New York, NY 10032

Donald Haas, M.D., M.P.H.
Mount Sinai School of Medicine, New York, NY 10029

4 References

1. 1

   Otsuka K, Cornelissen G, Halberg F, Oehlert G. Excessive circadian amplitude of blood pressure increases risk of ischaemic stroke and nephropathy. J Med Eng Technol 1997;21:23-30
   CrossRef | Web of Science | Medline

2. 2

   Thompson AM, Pickering TG. The role of ambulatory blood pressure monitoring in chronic and end-stage renal disease. Kidney Int (in press).
   

3. 3

   Kario K, Pickering TG, Umeda Y, et al. Morning surge in blood pressure as a predictor of silent and clinical cerebrovascular disease in elderly hypertensives: a prospective study. Circulation 2003;107:1401-1406
   CrossRef | Web of Science | Medline

4. 4

   Metoki H, Ohkubo T, Kikuya M, et al. Prognostic significance for stroke of a morning pressor surge and a nocturnal blood pressure decline: the Ohasama study. Hypertension 2006;47:149-154
   CrossRef | Web of Science | Medline

Citing Articles (2)

Citing Articles

1. 1

   Rosa Levandovski, Ana Harb, Fabiana Bernardi, Karla V. Allebrandt, Maria Paz Loayza Hidalgo. (2011) A chronobiological policy to decrease the burden of hypertension and obesity in low- and middle-income population. Biological Rhythm Research1-22
   CrossRef

2. 2

   Z Jiang, W Li, Y Liu, Y Wang, Z Wang, J Xiao, H Guo, G Cornélissen, F Halberg. (2010) Circadian blood pressure and heart rate characteristics in haemorrhagic vs ischaemic stroke in Chinese people. Journal of Human Hypertension 24:3, 165-174
   CrossRef