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Circadian changes of ambulatory blood pressure in an unselected population
Archives of Gerontology and Geriatrics 20 (1995) 185-191
ELSEVIER
ARCHIVES OF GERONTOLOGY AND GERIATRICS
Circadian changes of ambulatory blood pressure in an unselected population Fernando Antonio Prattichizzo*“, Fabio Galettab ‘Division of Internal Medicine, Civic Hospital, Son Minioto (PI), Italy bDeportment of Internol Medicine, University of Piso, Piso, Italy
Received 8 December 1993; revision received 14 October 1994; accepted 18 October 1994
Ah&act Ambulatory blood pressure monitoring does not interfere with the night-time blood pressure and heart rate reduction, typical haemodynamic effects of sleep. An unselected popula-
tion of 186 subjects was split into quartiles by age to assess the age related changes in 24-h blood pressure profile. From ambulatory blood pressure monitoring data we calculated daytime and night-time blood pressure and heart rate average values, as well as their percent difference. Results show that there is no difference with regard to nocturnal heart rate reduction (on average, 15%) between age groups or sexes, whereas nocturnal blood pressure reduction (on average, 10%) is significantly lower in elderly males, but not females, when compared with young people. This flat 24-h blood pressure profile is associated with hypertension. Circadian changes of ambulatory blood pressure are very different in elderly hypertensive men and provide a marker of diffuse arterial damage. Keywords:
Circadian rhythm; Blood pressure; Essential hypertension
1. IIltroduction
Ambulatory non-invasive blood pressure (BP) monitoring does not interfere with the night-time and heart rate (HR) reduction, typical haemodynamic effects of sleep (Schwan and Eriksson, 1992). There are several methods of evaluating BP variability, such as day-night BP difference, frequency of BP peaks, standard deviation, * Corresponding author, Via 2 Giugno n. 6, I-50057 Ponte a Elsa (FI), Italy. 0167-4943/95/$09.50 0 1995 Elsevier Science Ireland Ltd. All rights reserved SSDI 0167-4943(94)00595-X
186
F.A. Prattichizzo, F. Galettal Arch. Gerontol. Geriatr. 20 (1995) 185-191
cosinor approach, etc., most of which are under investigation. The circadian changes of BP have been shown to be similar in normotension and essential hypertension (Munakata et al., 1991). They have been used for the classification ‘dippers/nondippers’. There are some situations in which the fall in BP during sleep in hypertensive patients may be absent or reversed. Patients showing this phenomenon have been referred to as ‘non-dippers’ to distinguish them from normal ‘dippers’ (Pickering, 1991a). Such conditions are of interest for three reasons: (1) they may be helpful in understanding the regulation of BP during sleep and wakefulness; (2) the finding of an absent nocturnal BP fall may be of diagnostic value; (3) it may also have prognostic value (Pickering, 1991b). In the present study we tried to verify whether age, sex and hypertension influence the nocturnal BP decline. 2. Patients and methods An unselected population of normotensives and untreated essential hypertensives including 186 subjects (98 males, 88 females; age range, 18-90 years) was recruited for the study. They were consecutively chosen from referred patients with documented essential hypertension and healthy normotensive subjects examined in our laboratory. Subjects met the following criteria: (1) all hypertensives had either never been treated with or had discontinued antihypertensive drugs at least 2 weeks before ambulatory BP monitoring; (2) healthy normotensive subjects were volunteers chosen among hospital staff and other subjects examined for clinical check-up and found to be healthy. Secondary hypertension was ruled out by routine clinical and laboratory examinations. Only patients with essential hypertension in World Health Organization stage I or II were studied. The population was split into quartiles by age, as follows: Group Group Group Group
1, 2, 3, 4,
18-36 37-54 55-72 73-90
years; years; years; years.
The ambulatory BP was measured non-invasively for 24 h using the A & D Takeda Medical 2420 device, programmed to measure BP every 10 min during daytime and 15-30 min during night-time. The definition of day-time and night-time was made on the basis of wakefulness and sleep or bed rest periods, obtained from diary kept by each subject. On the day of ambulatory monitoring, the subjects followed their usual activities, implying a wide variety of activity levels and social constraints. The arm cuff was positioned on the non-dominant arm. The subjects were asked to refrain from movement and to keep their arm immobile during each measurement. We included only individuals with more than 100 successful readings. We considered subjects to be hypertensive if their mean 24-h ambulatory BP was greater than 129 mmHg systolic and/or 83 mmHg diastolic, on the basis of a preceding study (Prattichizzo, 1992). From monitoring data we calculated day-time and night-time BP and HR mean f S.D., as well as their percent difference
F.A. Prattichizzo, F. Galetta/Arch. Gerontol. Geriatr. 20 (1995) 185-191
187
Table I Number of hypertensives (H) and normotensives (N) according to age- and sex-groups Group
Males
Females
II
H
N
n
H
N
1 2 3 4
19 33 31 15
9 22 21 10
10 II IO 5
9 31 36 12
2 20 2s 8
7 II II 4
Total
98
62
36
88
55
33
(%A) f S.D. Student’s unpaired r-test was used for comparison of the four groups and a P value of co.05 was taken as a significant difference. 3. Results Hypertensive patients formed 63% of the study population and were equally distributed between age- and sex-groups (Table 1). There was no statistically significant difference in nocturnal HR decline between age groups or sexes (mean, 15%), whereas nocturnal BP decline (mean, 10%) was significantly lower in male subjects aged 73-90 (2.4 f 9.8%; 7 f 5.3%), when compared with male subjects aged 18-36 (11.9 f 6.2%; 11.8 f 5.7%) (P < 0.01for systolic and P < 0.05for diastolic BP decline). Tables 2 and 3, for, respectively, males and females show day-time and night-time systolic BP, diastolic BP and HR, with their related %A in the four groups. In order to discriminate between the effects of ageing and hypertension, we analysed the BP profile resulting from hourly averages in nine hypertensive and six normotensive elderly men of Group 4. As shown in Fig. 1, the elderly hypertensive men had a flat 24-h BP profile, with some post-prandial hypotension. In contrast, in elderly normotensive men the circadian rhythm was preserved, even if blunted and the postprandial hypotension persisted (Fig. 2). The difference between the percentage of nocturnal fall in males of Groups 1 and 4 was statistically significant only for systolic hypertension (10.7 f 7.7% vs. -1.8 f 10.5%; P < 0.02) and diastolic hypertension (13.1 * 7.7% vs. -4.5 f 0%; P < 0.01) (Table 4). All the elderly hypertensive men had a history of atherosclerotic cardiovascular disease, such as symptoms of intermittent claudication, or angina pectoris, or transient ischaemic attacks, whereas elderly normotensive men and elderly women had a low prevalence of such symptoms. 4.
-on
The study population was not chosen as a ‘random’ sample, but as an ‘unselected’ series of patients, referred to our Centre in order to assess BP profile.
(beats/min) Sys BP Dia BP HR
111.9 f 12.3 69.4 zt 9.3
Night
Sys Dia HR %A %A %A
BP (mmHg) BP (mmHg) (beats/min) Sys BP Dia BP HR
Age (years) Range Mean Number
111.9 f 20.8 15.8 f 10.9 84.3 f 3.8 1I.5 zt 14.4 zt 15.8 zt
Day 99.0 f 11.8 64.9 f 10.6 11.0 f 8.2 4.8 6.9 10.0
Night
18-36 29.9 zt 5.3 9
18.2 f
Night
31-54 41.8 f 4.1 31
blood pressure
15.1 f
123.4 f 15.1 13.6 zt 8.5
Night
15.9 64.3 + 9.2 11.3 zt 8.2 1.3 + 8.3 16.6 f 9.9
139.5 f 14.1 80.1 f 9.2
Day
55-12 63.3 jz 4.5 31
Night 136.5 f 13.5 122.4 f 15.9 84.1 zt 9.1 15.3 zt 8.2 11.9 f 10.1 66.3 f 10.1 10.4 f 7.1 10.1 f 1.1 14.5 f 1.2
Day
55-12 63.1 f 4.9 36
Night 143.2 ztz26.3 130.3 + 25.9 13.1 f 9.6 68.3 f 11.9 71.9 f 8.1 63.1 + 5.9 9.0 f 6.8 9.4 f 8.3 11.4 f 1.1
Day
10.2
(%A) in females
13-90 19.2 f 5.2 12
differences
11.9 f 1.9 63.3 f 2.4 f 9.8 1.0 f 5.3 12.0 ?? 11.2
132.2 f 18.9 67.9 zt 8.6
Night
13-90 80.4 f 4.1 1s
(%A) in males (values
135.5 f 12.0 13.0 f 6.4
Day
(Dia BP), heart rate (HR) and their percent
125.4 + 15.3 101.1 z+z15.3 81.3 + 8.5 16.7 zt sl.l 82.4 + 5.5 69.4 f 6.8 14.1 f 8.6 12.1 f 8.5 16.1 f 6.9
Day
122.1 f 11.2 71.8 f 11.2
Night
10.0 64.8 f 8.4 8.1 f 9.4 8.5 f 1.4 11.5 ?? 9.1
133.7 zk 14.6 84.8 f 9.4
Day
31-54 45.8 f 5.1 33
blood pressure (Dia BP), heart rate (HR) and their percent differences
(Sys BP), diastolic
15.1 f 8.1 63.6 f 1.9 11.9 f 6.2 11.8 zt 5.1 15.3 zrz9.2
127.1 f 10.7 18.1 f 9.1
Day
18-36 21.3 zt 6.0 19
Table 3 Day-time and night-time systolic blood pressure (values were expressed as means f S.D.)
HR %A %A %A
SysBP (mmHg) Dia BP (mmHg)
Age (years) Range Mean Number
Table 2 Day-time and night-time systolic blood pressure (Sys BP) diastolic were expressed as means f SD.)
F.A. Prattichizzo, F. Galetta/Arch. Gerontol. Geriatr. 20 (1995) 185-191
189
BP 200 100
l(K 14c
12( lo( 81 8 mml
12
14
16
18
20
22
L
24
2
4
6
8
10
12
time(h)
Fig. I. Hourly average values of systolic and diastolic blood pressure in elderly hypertensive men (mean f standard deviation).
time(h)
Fig. 2. Hourly average values of systolic and diastolic blood pressure in elderly normotensive men (mean * standard deviation).
190
F.A. Prattichizzo, F. Galetta /Arch. Gerontol. Geriatr. 20 (1995) 185-191
Table 4 Percent difference (“%A)in male hypertensive and normotensive subjects of Group I and 4
Group I Sys hypertension Dia hypertension Sys normotension Dia normotension Group 4 Sys hypertension Dia hypertension Sys normotension Dia normotension
Number
%A
8 6 11 13
10.7 f 13.1 f 12.8 f 11.0 f
7.7 7.7 5.0 4.7
28 f 32 zt 27 f 25 f
5.7 3.9 6.5 5.5
9 1 6 14
-1.8 -4.5 9.1 7.6
10.5 0 2.5 4.6
80 f 75 f 81 f 81 f
4.4 0 3.8 4.0
Age (years)
f f f f
Values are expressed as means f S.D.
Ambulatory BP monitoring was performed by the TM-2420 automated sphygmomanometer, a device tested in use, found to be within the specifications of the Association for the Advancement of Medical Instrumentation and also found to reflect intra-arterial pressure reasonably well (Clarke et al., 1991). Although the circadian rhythm of BP is characterized by a diurnal increase and by a nocturnal decrease, there is no clear explanation of the mechanism responsible for this rhythm. Nevertheless, day-night changes in BP have been unequivocally shown to depend mostly on behavioral factors (Pickering, 1991b). Some studies showed that the circadian rhythm of BP does not differ greatly between younger and older subjects (Drayer et al., 1982; Kennedy et al., 1983). This is unexpected, since older people tend to sleep less and have a more fragmented sleep pattern than the young. There are some individuals whose pressure does not fall during the night, and indeed, who have more evidence of cardiovascular disease (Kobrin et al., 1984). Recently an impaired nocturnal fall in BP was found in elderly hypertensive patients with left ventricular hypertrophy. Some authors found that the nocturnal fall in systolic BP was lower in patients with left ventricular hypertrophy when compared with those with normal left ventricular mass (Kuwajima et al., 1992). In another study an inverse correlation between the left ventricular mass index and the percent nocturnal decline relative to the day-time ambulatory BP was found (Verdecchia et al., 1990). Our results somewhat agree with those studies, showing that the diurnal BP rhythm is lost in elderly hypertensive men and blunted in elderly normotensive men. Atherosclerotic cardiovascular disease and left ventricular hypertrophy are 2-3 times more prevalent in elderly hypertensive patients who do not have a physiologic fall in BP during sleep, than in those with a nocturnal BP reduction (Kobrin et al., 1984). So, the real difference between hypertensive and normotensive elderly men with regard to nocturnal BP change seems to be related to a pathological state rather than ageing. Also, the sex influence on diurnal rhythm seems to support our data:
F.A. Prattichizzo, F. Galetta/ Arch. Gerontol. Geriatr. 20 (1995) 185-191
191
intra-arterial BP monitoring in normal subjects showed that day-time pressure differs little between sexes, but nocturnal BP in women is lower than in men (Broadhurst et al., 1990). Our finding of preserved circadian rhythm also in elderly women may contribute to explaining why previous clinical trials suggested that the benefits of treatment may be less or even negative in females (Staessen et al., 1983; Medical Research Council Working Party, 1985) and why hypertensive women seem to require a higher BP workload in 24 h to develop left ventricular hypertrophy (Verdecchia and Porcellati, 1992). Nocturnal BP drop can be, therefore, influenced by age, sex and hypertension, besides an easily intelligible series of methodologic parameters, such as the number of BP measurements and the definition of day-time and night-time subperiods. References Broadhurst, P., Brigden, G., Dasgupta, P., Lahiri, A. and Raftery, E.B. (1990): Ambulatory intra-arterial BP in normal subjects. Am. Heart J., 120, 160-166. Clarke, S., Fowlie, S. and Coats, A. (1991): Ambulatory blood pressure monitoring: validation of the accuracy and reliability-of the TM-2420 according to the AAMI recommendations. J. Hum. Hypertens., 5, 17-82. Drayer, J.I.M., Weber, M.A., DeYoung, J.L. and Wyke, F.A. (1982): Circadian blood pressure patterns in ambulatory hypertensive patients. Effects of age. Am. J. Med. , 73, 493-499. Kennedy, H.L., Horan, M.J., Sprague, M.K., Padgett, N.E. and Shriver, K.K. (1983): Ambulatory blood pressure in healthy normotensive males. Am. Heart J., 106, 717-722. Kobrin, I., Oigman, W., Kumar, A., Ventura, H.O., Messerli, F.H., Frohlich, E.D. and Dunn, F.G. (1984): Diurnal variation of blood pressure in elderly patients with essential hypertension. Am. Geriatr. Sot., 32, 896-899. Kuwajima, l., Suzuki, Y., Shimosawa, T., Kanemaru, A., Hoshino, S. and Kuramoto, K. (1992): Diminished nocturnal decline in blood pressure in elderly hypertensive patients with left ventricular hypertrophy. Am. Heart J., 123, 1307-1311. Medical Research Council Working Party (1985): MRC trial of treatment of mild hypertension: principal results. Br. Med. J., 291, 97-104. Munakata, M., Imai, Y., Abe, K., Sasaki, S., Minami, N., Hashimoto, J., Sakuma, H., lchijo, T., Yoshiiwa, M., Sekino, H. and Yoshinaga, K. (1991): Assessment of age-dependent changes in circadian blood pressure rhythm in patients with essential hypertension. J. Hypertens., 9, 407-415. Pickering, T.G. (199la): The clinical significance of diurnal blood pressure variations: dippers and nondippers. Circulation, 8 I, 700-702. Pickering, T.G. (199lb): Ambulatory Monitoring and Blood Pressure Variability. Science Press LTD, London, 5, 9. Prattichizao, F.A. (1992): Indagine sui limiti di normalita della pressione arteriosa monitorata. G.B. Clin. Terapia, 2, 21-25. Schwan, A. and Eriksson, G. (1992): Effect on sleep - but not on blood pressure - of nocturnal noninvasive blood pressure monitoring. J. Hypertens., IO, 189-194. Staessen, J., Cattaert, A., Fagard, R., Lijnen, P., Vanhees, L. and Amery, A. (1983): Epidemiology ol treated, compared to untreated hypertension. In: Hypertension, pp. 1069-1093. Editors: J. Genest et al. McGraw-Hill, New York. Verdecchia, P., Schillaci, G., Guerrieri,M., Gatteschi, C., Benemio, G., Boldrini, F. and Porcellati, C. (1990): Circadian blood pressure changes and left ventricular hypertrophy in essential hypertension. Circulation, 81, 528-536. Verdecchia, P. and Porcellati, C. (1992): Day-night change of ambulatory blood pressure: another risk marker in essential hypertension? G. Ital. Cardiol., 22, 879-886.
ELSEVIER
ARCHIVES OF GERONTOLOGY AND GERIATRICS
Circadian changes of ambulatory blood pressure in an unselected population Fernando Antonio Prattichizzo*“, Fabio Galettab ‘Division of Internal Medicine, Civic Hospital, Son Minioto (PI), Italy bDeportment of Internol Medicine, University of Piso, Piso, Italy
Received 8 December 1993; revision received 14 October 1994; accepted 18 October 1994
Ah&act Ambulatory blood pressure monitoring does not interfere with the night-time blood pressure and heart rate reduction, typical haemodynamic effects of sleep. An unselected popula-
tion of 186 subjects was split into quartiles by age to assess the age related changes in 24-h blood pressure profile. From ambulatory blood pressure monitoring data we calculated daytime and night-time blood pressure and heart rate average values, as well as their percent difference. Results show that there is no difference with regard to nocturnal heart rate reduction (on average, 15%) between age groups or sexes, whereas nocturnal blood pressure reduction (on average, 10%) is significantly lower in elderly males, but not females, when compared with young people. This flat 24-h blood pressure profile is associated with hypertension. Circadian changes of ambulatory blood pressure are very different in elderly hypertensive men and provide a marker of diffuse arterial damage. Keywords:
Circadian rhythm; Blood pressure; Essential hypertension
1. IIltroduction
Ambulatory non-invasive blood pressure (BP) monitoring does not interfere with the night-time and heart rate (HR) reduction, typical haemodynamic effects of sleep (Schwan and Eriksson, 1992). There are several methods of evaluating BP variability, such as day-night BP difference, frequency of BP peaks, standard deviation, * Corresponding author, Via 2 Giugno n. 6, I-50057 Ponte a Elsa (FI), Italy. 0167-4943/95/$09.50 0 1995 Elsevier Science Ireland Ltd. All rights reserved SSDI 0167-4943(94)00595-X
186
F.A. Prattichizzo, F. Galettal Arch. Gerontol. Geriatr. 20 (1995) 185-191
cosinor approach, etc., most of which are under investigation. The circadian changes of BP have been shown to be similar in normotension and essential hypertension (Munakata et al., 1991). They have been used for the classification ‘dippers/nondippers’. There are some situations in which the fall in BP during sleep in hypertensive patients may be absent or reversed. Patients showing this phenomenon have been referred to as ‘non-dippers’ to distinguish them from normal ‘dippers’ (Pickering, 1991a). Such conditions are of interest for three reasons: (1) they may be helpful in understanding the regulation of BP during sleep and wakefulness; (2) the finding of an absent nocturnal BP fall may be of diagnostic value; (3) it may also have prognostic value (Pickering, 1991b). In the present study we tried to verify whether age, sex and hypertension influence the nocturnal BP decline. 2. Patients and methods An unselected population of normotensives and untreated essential hypertensives including 186 subjects (98 males, 88 females; age range, 18-90 years) was recruited for the study. They were consecutively chosen from referred patients with documented essential hypertension and healthy normotensive subjects examined in our laboratory. Subjects met the following criteria: (1) all hypertensives had either never been treated with or had discontinued antihypertensive drugs at least 2 weeks before ambulatory BP monitoring; (2) healthy normotensive subjects were volunteers chosen among hospital staff and other subjects examined for clinical check-up and found to be healthy. Secondary hypertension was ruled out by routine clinical and laboratory examinations. Only patients with essential hypertension in World Health Organization stage I or II were studied. The population was split into quartiles by age, as follows: Group Group Group Group
1, 2, 3, 4,
18-36 37-54 55-72 73-90
years; years; years; years.
The ambulatory BP was measured non-invasively for 24 h using the A & D Takeda Medical 2420 device, programmed to measure BP every 10 min during daytime and 15-30 min during night-time. The definition of day-time and night-time was made on the basis of wakefulness and sleep or bed rest periods, obtained from diary kept by each subject. On the day of ambulatory monitoring, the subjects followed their usual activities, implying a wide variety of activity levels and social constraints. The arm cuff was positioned on the non-dominant arm. The subjects were asked to refrain from movement and to keep their arm immobile during each measurement. We included only individuals with more than 100 successful readings. We considered subjects to be hypertensive if their mean 24-h ambulatory BP was greater than 129 mmHg systolic and/or 83 mmHg diastolic, on the basis of a preceding study (Prattichizzo, 1992). From monitoring data we calculated day-time and night-time BP and HR mean f S.D., as well as their percent difference
F.A. Prattichizzo, F. Galetta/Arch. Gerontol. Geriatr. 20 (1995) 185-191
187
Table I Number of hypertensives (H) and normotensives (N) according to age- and sex-groups Group
Males
Females
II
H
N
n
H
N
1 2 3 4
19 33 31 15
9 22 21 10
10 II IO 5
9 31 36 12
2 20 2s 8
7 II II 4
Total
98
62
36
88
55
33
(%A) f S.D. Student’s unpaired r-test was used for comparison of the four groups and a P value of co.05 was taken as a significant difference. 3. Results Hypertensive patients formed 63% of the study population and were equally distributed between age- and sex-groups (Table 1). There was no statistically significant difference in nocturnal HR decline between age groups or sexes (mean, 15%), whereas nocturnal BP decline (mean, 10%) was significantly lower in male subjects aged 73-90 (2.4 f 9.8%; 7 f 5.3%), when compared with male subjects aged 18-36 (11.9 f 6.2%; 11.8 f 5.7%) (P < 0.01for systolic and P < 0.05for diastolic BP decline). Tables 2 and 3, for, respectively, males and females show day-time and night-time systolic BP, diastolic BP and HR, with their related %A in the four groups. In order to discriminate between the effects of ageing and hypertension, we analysed the BP profile resulting from hourly averages in nine hypertensive and six normotensive elderly men of Group 4. As shown in Fig. 1, the elderly hypertensive men had a flat 24-h BP profile, with some post-prandial hypotension. In contrast, in elderly normotensive men the circadian rhythm was preserved, even if blunted and the postprandial hypotension persisted (Fig. 2). The difference between the percentage of nocturnal fall in males of Groups 1 and 4 was statistically significant only for systolic hypertension (10.7 f 7.7% vs. -1.8 f 10.5%; P < 0.02) and diastolic hypertension (13.1 * 7.7% vs. -4.5 f 0%; P < 0.01) (Table 4). All the elderly hypertensive men had a history of atherosclerotic cardiovascular disease, such as symptoms of intermittent claudication, or angina pectoris, or transient ischaemic attacks, whereas elderly normotensive men and elderly women had a low prevalence of such symptoms. 4.
-on
The study population was not chosen as a ‘random’ sample, but as an ‘unselected’ series of patients, referred to our Centre in order to assess BP profile.
(beats/min) Sys BP Dia BP HR
111.9 f 12.3 69.4 zt 9.3
Night
Sys Dia HR %A %A %A
BP (mmHg) BP (mmHg) (beats/min) Sys BP Dia BP HR
Age (years) Range Mean Number
111.9 f 20.8 15.8 f 10.9 84.3 f 3.8 1I.5 zt 14.4 zt 15.8 zt
Day 99.0 f 11.8 64.9 f 10.6 11.0 f 8.2 4.8 6.9 10.0
Night
18-36 29.9 zt 5.3 9
18.2 f
Night
31-54 41.8 f 4.1 31
blood pressure
15.1 f
123.4 f 15.1 13.6 zt 8.5
Night
15.9 64.3 + 9.2 11.3 zt 8.2 1.3 + 8.3 16.6 f 9.9
139.5 f 14.1 80.1 f 9.2
Day
55-12 63.3 jz 4.5 31
Night 136.5 f 13.5 122.4 f 15.9 84.1 zt 9.1 15.3 zt 8.2 11.9 f 10.1 66.3 f 10.1 10.4 f 7.1 10.1 f 1.1 14.5 f 1.2
Day
55-12 63.1 f 4.9 36
Night 143.2 ztz26.3 130.3 + 25.9 13.1 f 9.6 68.3 f 11.9 71.9 f 8.1 63.1 + 5.9 9.0 f 6.8 9.4 f 8.3 11.4 f 1.1
Day
10.2
(%A) in females
13-90 19.2 f 5.2 12
differences
11.9 f 1.9 63.3 f 2.4 f 9.8 1.0 f 5.3 12.0 ?? 11.2
132.2 f 18.9 67.9 zt 8.6
Night
13-90 80.4 f 4.1 1s
(%A) in males (values
135.5 f 12.0 13.0 f 6.4
Day
(Dia BP), heart rate (HR) and their percent
125.4 + 15.3 101.1 z+z15.3 81.3 + 8.5 16.7 zt sl.l 82.4 + 5.5 69.4 f 6.8 14.1 f 8.6 12.1 f 8.5 16.1 f 6.9
Day
122.1 f 11.2 71.8 f 11.2
Night
10.0 64.8 f 8.4 8.1 f 9.4 8.5 f 1.4 11.5 ?? 9.1
133.7 zk 14.6 84.8 f 9.4
Day
31-54 45.8 f 5.1 33
blood pressure (Dia BP), heart rate (HR) and their percent differences
(Sys BP), diastolic
15.1 f 8.1 63.6 f 1.9 11.9 f 6.2 11.8 zt 5.1 15.3 zrz9.2
127.1 f 10.7 18.1 f 9.1
Day
18-36 21.3 zt 6.0 19
Table 3 Day-time and night-time systolic blood pressure (values were expressed as means f S.D.)
HR %A %A %A
SysBP (mmHg) Dia BP (mmHg)
Age (years) Range Mean Number
Table 2 Day-time and night-time systolic blood pressure (Sys BP) diastolic were expressed as means f SD.)
F.A. Prattichizzo, F. Galetta/Arch. Gerontol. Geriatr. 20 (1995) 185-191
189
BP 200 100
l(K 14c
12( lo( 81 8 mml
12
14
16
18
20
22
L
24
2
4
6
8
10
12
time(h)
Fig. I. Hourly average values of systolic and diastolic blood pressure in elderly hypertensive men (mean f standard deviation).
time(h)
Fig. 2. Hourly average values of systolic and diastolic blood pressure in elderly normotensive men (mean * standard deviation).
190
F.A. Prattichizzo, F. Galetta /Arch. Gerontol. Geriatr. 20 (1995) 185-191
Table 4 Percent difference (“%A)in male hypertensive and normotensive subjects of Group I and 4
Group I Sys hypertension Dia hypertension Sys normotension Dia normotension Group 4 Sys hypertension Dia hypertension Sys normotension Dia normotension
Number
%A
8 6 11 13
10.7 f 13.1 f 12.8 f 11.0 f
7.7 7.7 5.0 4.7
28 f 32 zt 27 f 25 f
5.7 3.9 6.5 5.5
9 1 6 14
-1.8 -4.5 9.1 7.6
10.5 0 2.5 4.6
80 f 75 f 81 f 81 f
4.4 0 3.8 4.0
Age (years)
f f f f
Values are expressed as means f S.D.
Ambulatory BP monitoring was performed by the TM-2420 automated sphygmomanometer, a device tested in use, found to be within the specifications of the Association for the Advancement of Medical Instrumentation and also found to reflect intra-arterial pressure reasonably well (Clarke et al., 1991). Although the circadian rhythm of BP is characterized by a diurnal increase and by a nocturnal decrease, there is no clear explanation of the mechanism responsible for this rhythm. Nevertheless, day-night changes in BP have been unequivocally shown to depend mostly on behavioral factors (Pickering, 1991b). Some studies showed that the circadian rhythm of BP does not differ greatly between younger and older subjects (Drayer et al., 1982; Kennedy et al., 1983). This is unexpected, since older people tend to sleep less and have a more fragmented sleep pattern than the young. There are some individuals whose pressure does not fall during the night, and indeed, who have more evidence of cardiovascular disease (Kobrin et al., 1984). Recently an impaired nocturnal fall in BP was found in elderly hypertensive patients with left ventricular hypertrophy. Some authors found that the nocturnal fall in systolic BP was lower in patients with left ventricular hypertrophy when compared with those with normal left ventricular mass (Kuwajima et al., 1992). In another study an inverse correlation between the left ventricular mass index and the percent nocturnal decline relative to the day-time ambulatory BP was found (Verdecchia et al., 1990). Our results somewhat agree with those studies, showing that the diurnal BP rhythm is lost in elderly hypertensive men and blunted in elderly normotensive men. Atherosclerotic cardiovascular disease and left ventricular hypertrophy are 2-3 times more prevalent in elderly hypertensive patients who do not have a physiologic fall in BP during sleep, than in those with a nocturnal BP reduction (Kobrin et al., 1984). So, the real difference between hypertensive and normotensive elderly men with regard to nocturnal BP change seems to be related to a pathological state rather than ageing. Also, the sex influence on diurnal rhythm seems to support our data:
F.A. Prattichizzo, F. Galetta/ Arch. Gerontol. Geriatr. 20 (1995) 185-191
191
intra-arterial BP monitoring in normal subjects showed that day-time pressure differs little between sexes, but nocturnal BP in women is lower than in men (Broadhurst et al., 1990). Our finding of preserved circadian rhythm also in elderly women may contribute to explaining why previous clinical trials suggested that the benefits of treatment may be less or even negative in females (Staessen et al., 1983; Medical Research Council Working Party, 1985) and why hypertensive women seem to require a higher BP workload in 24 h to develop left ventricular hypertrophy (Verdecchia and Porcellati, 1992). Nocturnal BP drop can be, therefore, influenced by age, sex and hypertension, besides an easily intelligible series of methodologic parameters, such as the number of BP measurements and the definition of day-time and night-time subperiods. References Broadhurst, P., Brigden, G., Dasgupta, P., Lahiri, A. and Raftery, E.B. (1990): Ambulatory intra-arterial BP in normal subjects. Am. Heart J., 120, 160-166. Clarke, S., Fowlie, S. and Coats, A. (1991): Ambulatory blood pressure monitoring: validation of the accuracy and reliability-of the TM-2420 according to the AAMI recommendations. J. Hum. Hypertens., 5, 17-82. Drayer, J.I.M., Weber, M.A., DeYoung, J.L. and Wyke, F.A. (1982): Circadian blood pressure patterns in ambulatory hypertensive patients. Effects of age. Am. J. Med. , 73, 493-499. Kennedy, H.L., Horan, M.J., Sprague, M.K., Padgett, N.E. and Shriver, K.K. (1983): Ambulatory blood pressure in healthy normotensive males. Am. Heart J., 106, 717-722. Kobrin, I., Oigman, W., Kumar, A., Ventura, H.O., Messerli, F.H., Frohlich, E.D. and Dunn, F.G. (1984): Diurnal variation of blood pressure in elderly patients with essential hypertension. Am. Geriatr. Sot., 32, 896-899. Kuwajima, l., Suzuki, Y., Shimosawa, T., Kanemaru, A., Hoshino, S. and Kuramoto, K. (1992): Diminished nocturnal decline in blood pressure in elderly hypertensive patients with left ventricular hypertrophy. Am. Heart J., 123, 1307-1311. Medical Research Council Working Party (1985): MRC trial of treatment of mild hypertension: principal results. Br. Med. J., 291, 97-104. Munakata, M., Imai, Y., Abe, K., Sasaki, S., Minami, N., Hashimoto, J., Sakuma, H., lchijo, T., Yoshiiwa, M., Sekino, H. and Yoshinaga, K. (1991): Assessment of age-dependent changes in circadian blood pressure rhythm in patients with essential hypertension. J. Hypertens., 9, 407-415. Pickering, T.G. (199la): The clinical significance of diurnal blood pressure variations: dippers and nondippers. Circulation, 8 I, 700-702. Pickering, T.G. (199lb): Ambulatory Monitoring and Blood Pressure Variability. Science Press LTD, London, 5, 9. Prattichizao, F.A. (1992): Indagine sui limiti di normalita della pressione arteriosa monitorata. G.B. Clin. Terapia, 2, 21-25. Schwan, A. and Eriksson, G. (1992): Effect on sleep - but not on blood pressure - of nocturnal noninvasive blood pressure monitoring. J. Hypertens., IO, 189-194. Staessen, J., Cattaert, A., Fagard, R., Lijnen, P., Vanhees, L. and Amery, A. (1983): Epidemiology ol treated, compared to untreated hypertension. In: Hypertension, pp. 1069-1093. Editors: J. Genest et al. McGraw-Hill, New York. Verdecchia, P., Schillaci, G., Guerrieri,M., Gatteschi, C., Benemio, G., Boldrini, F. and Porcellati, C. (1990): Circadian blood pressure changes and left ventricular hypertrophy in essential hypertension. Circulation, 81, 528-536. Verdecchia, P. and Porcellati, C. (1992): Day-night change of ambulatory blood pressure: another risk marker in essential hypertension? G. Ital. Cardiol., 22, 879-886.