Drugs 44 (Supp!. I): 17-22, 1992 0012-6667/92/0100-0017/$3.00/0 © Adis International Limited. All rights reserved. DRSUP3380
Ambulatory Blood Pressure Monitoring G. M ancia, S. Omboni, A. Ravogli, A. Frattola and A. Villani Cattedra di Medicina Interna, Ospedale S. Gerardo, Monza, and Clinica Medica, Ospedale Maggiore, Universita di Milano and Centro Auxologico Italiano, Milan, Italy
Summary
This paper reviews the evidence that, in patients with hypertension, end-organ damage correlates more closely with blood pressure values obtained by ambulatory blood pressure monitoring than with those obtained by conventional sphygmomanometry. However, ambulatory blood pressure monitoring is not suitable for routine use in the clinical setting because of a lack of standard reference values and data regarding the prognostic significance of this method. Ambulatory blood pressure values are reproducible and this method avoids the so-called placebo effect; thus, this method is useful in clinical studies investigating the efficacy and duration of action of antihypertensive drugs. Data from 1 study in which hypertensive patients were treated with slow release verapamil 240mg, enalapril 20mg, nitrendipine 20mg and placebo, given once daily for 8 weeks according to a double-blind parallel group design, showed that mean 24-hour ambulatory blood pressure was reduced by all 3 drugs compared with placebo. Verapamil and enalapril showed similar antihypertensive efficacy and both drugs reduced night-time blood pressure more effectively than nitrendipine.
This paper will address 3 issues: the role of ambulatory blood pressure monitoring in the diagnosis of hypertension and the estimate of the risk; the advantages of ambulatory blood pressure monitoring in studies of antihypertensive treatment; and the results obtained in a large clinical study that has used ambulatory blood pressure monitoring to compare the antihypertensive effect of verapamil with that of other commonly used antihypertensive drugs.
1. Ambulatory Blood Pressure Monitoring and Diagnosis of Hypertension Several studies have shown that the end-organ damage associated with hypertension is more closely related to 24-hour average blood pressure (measured either intra-arterially or noninvasively) than to traditional clinical blood pressure meas-
urements obtained with a sphygmcmanometer. This is shown when end-organ damage is assessed by an overall score based on patient history, laboratory examination and clinical data (Parati et al. 1987; Sokolow et al. 1966). It is also shown when the damage is detected by more sensitive indices of specific organ alterations such as an increase in left ventricular mass (Mancia 1990), an abnormality in systolic and diastolic function (White et al. 1989), an increase in cerebral lacunae (Sluniade et al. 1990) and albuminuria. This suggests that ambulatory blood pressure data have some clinical value. It does not prove the superiority of ambulatory blood pressure over the traditional method of measurement, however, because cross-sectional studies of the type referred to above (i.e. studies evaluating ambulatory blood pressure and endorgan damage simultaneously) have a limited sci-
Drugs 44 (Suppl. 1) 1992
18
entific value. Only longitudinal studies (i.e. studies in which patients are followed-up over several years) have the potential to show the greater benefit of ambulatory blood pressure in predicting the future development of end-organ damage, cardiovascular morbidity and mortality compared with clinical blood pressure measurements. Results of such a study are not yet available and the 'longitudinal' evidence so far is limited to retrospective analyses of patients followed for a number of years (Perloff et al. 1991). Three prospective trials currently under way will provide useful data: (I) the Systeur study will examine the protective effect of treatment of systolic hypertension in the elderly but will also include investigation of the prognostic value of ambulatory vs clinic blood pressure measurements (Staessen et al. 1992); (2) the OVA study, which aims to compare the ability of ambulatory and clinic blood
pressure monitoring to predict left ventricular hypertrophy (Clement 1990); and (3) the Italian study, which will compare the ability of ambulatory and clinic blood pressure monitoring to predict the regression of left ventricular hypertrophy induced by antihypertensive treatment (Omboni et al. 1992). The goal of these studies is not only to determine which method of measuring blood pressure is most appropriate but also to see whether the power to predict the development of the complications associated with hypertension is enhanced by using the 2 methods together.
2. Ambulatory Blood Pressure Monitoring and Antihypertensive Treatment Ambulatory blood pressure monitoring should not be routinely employed to assess the efficacy of
o
160
•
Control Placebo Systolic
140
"6i J:
E
S. I!! ~
120
!II !II
I!! Co
815
100
DiastOliC
c as
CD
~
60
60
1200
1400
1600
1800 2000
2200
0000
0200
0400
0600
0800
1000
1200
Time (hours)
Fig. 1. Results of 24-hour automatic ambulatory blood pressure monitoring (ABPM) before and after 4 weeks of placebo administration. Data shown are hourly means (± SE) from 27 patients with essential hypertension. * p < 0.05, placebo vs control (after Mutti et al. 1991, with permission).
Ambulatory Blood Pressure Monitoring
o
19
Clinic
• Ambulatory blood pressure monitoring Systolic blood pressure
Oi
170
J:
E
§. 160 f!!
::>
Ambulatory Blood Pressure Monitoring G. M ancia, S. Omboni, A. Ravogli, A. Frattola and A. Villani Cattedra di Medicina Interna, Ospedale S. Gerardo, Monza, and Clinica Medica, Ospedale Maggiore, Universita di Milano and Centro Auxologico Italiano, Milan, Italy
Summary
This paper reviews the evidence that, in patients with hypertension, end-organ damage correlates more closely with blood pressure values obtained by ambulatory blood pressure monitoring than with those obtained by conventional sphygmomanometry. However, ambulatory blood pressure monitoring is not suitable for routine use in the clinical setting because of a lack of standard reference values and data regarding the prognostic significance of this method. Ambulatory blood pressure values are reproducible and this method avoids the so-called placebo effect; thus, this method is useful in clinical studies investigating the efficacy and duration of action of antihypertensive drugs. Data from 1 study in which hypertensive patients were treated with slow release verapamil 240mg, enalapril 20mg, nitrendipine 20mg and placebo, given once daily for 8 weeks according to a double-blind parallel group design, showed that mean 24-hour ambulatory blood pressure was reduced by all 3 drugs compared with placebo. Verapamil and enalapril showed similar antihypertensive efficacy and both drugs reduced night-time blood pressure more effectively than nitrendipine.
This paper will address 3 issues: the role of ambulatory blood pressure monitoring in the diagnosis of hypertension and the estimate of the risk; the advantages of ambulatory blood pressure monitoring in studies of antihypertensive treatment; and the results obtained in a large clinical study that has used ambulatory blood pressure monitoring to compare the antihypertensive effect of verapamil with that of other commonly used antihypertensive drugs.
1. Ambulatory Blood Pressure Monitoring and Diagnosis of Hypertension Several studies have shown that the end-organ damage associated with hypertension is more closely related to 24-hour average blood pressure (measured either intra-arterially or noninvasively) than to traditional clinical blood pressure meas-
urements obtained with a sphygmcmanometer. This is shown when end-organ damage is assessed by an overall score based on patient history, laboratory examination and clinical data (Parati et al. 1987; Sokolow et al. 1966). It is also shown when the damage is detected by more sensitive indices of specific organ alterations such as an increase in left ventricular mass (Mancia 1990), an abnormality in systolic and diastolic function (White et al. 1989), an increase in cerebral lacunae (Sluniade et al. 1990) and albuminuria. This suggests that ambulatory blood pressure data have some clinical value. It does not prove the superiority of ambulatory blood pressure over the traditional method of measurement, however, because cross-sectional studies of the type referred to above (i.e. studies evaluating ambulatory blood pressure and endorgan damage simultaneously) have a limited sci-
Drugs 44 (Suppl. 1) 1992
18
entific value. Only longitudinal studies (i.e. studies in which patients are followed-up over several years) have the potential to show the greater benefit of ambulatory blood pressure in predicting the future development of end-organ damage, cardiovascular morbidity and mortality compared with clinical blood pressure measurements. Results of such a study are not yet available and the 'longitudinal' evidence so far is limited to retrospective analyses of patients followed for a number of years (Perloff et al. 1991). Three prospective trials currently under way will provide useful data: (I) the Systeur study will examine the protective effect of treatment of systolic hypertension in the elderly but will also include investigation of the prognostic value of ambulatory vs clinic blood pressure measurements (Staessen et al. 1992); (2) the OVA study, which aims to compare the ability of ambulatory and clinic blood
pressure monitoring to predict left ventricular hypertrophy (Clement 1990); and (3) the Italian study, which will compare the ability of ambulatory and clinic blood pressure monitoring to predict the regression of left ventricular hypertrophy induced by antihypertensive treatment (Omboni et al. 1992). The goal of these studies is not only to determine which method of measuring blood pressure is most appropriate but also to see whether the power to predict the development of the complications associated with hypertension is enhanced by using the 2 methods together.
2. Ambulatory Blood Pressure Monitoring and Antihypertensive Treatment Ambulatory blood pressure monitoring should not be routinely employed to assess the efficacy of
o
160
•
Control Placebo Systolic
140
"6i J:
E
S. I!! ~
120
!II !II
I!! Co
815
100
DiastOliC
c as
CD
~
60
60
1200
1400
1600
1800 2000
2200
0000
0200
0400
0600
0800
1000
1200
Time (hours)
Fig. 1. Results of 24-hour automatic ambulatory blood pressure monitoring (ABPM) before and after 4 weeks of placebo administration. Data shown are hourly means (± SE) from 27 patients with essential hypertension. * p < 0.05, placebo vs control (after Mutti et al. 1991, with permission).
Ambulatory Blood Pressure Monitoring
o
19
Clinic
• Ambulatory blood pressure monitoring Systolic blood pressure
Oi
170
J:
E
§. 160 f!!
::>
