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Office hypertension: abnormal blood pressure regulation and increased sympathetic activity compared with normotension
Insights
Office hypertension, characterized by high blood pressure readings only in clinical settings, shows abnormal blood pressure regulation and increased sympathetic activity compared to normotensive individuals. This suggests it may be an early sign of hypertension.
Area of Science:
- Cardiology
- Hypertension Research
- Clinical Physiology
Background:
- Office hypertension affects 20-30% of hypertensive patients, distinguished from established hypertension by measurements outside clinical settings.
- The underlying mechanisms and out-of-office blood pressure behavior of office hypertensives remain poorly understood.
- Existing data lacks comparison of blood pressure patterns between office hypertensives and normotensive subjects in non-clinical environments.
Purpose of the Study:
- To investigate the 24-hour blood pressure behavior of patients diagnosed with office hypertension.
- To compare the ambulatory blood pressure patterns of office hypertensives with those of matched normotensive individuals.
Main Methods:
- Ambulatory blood pressure monitoring (ABPM) was used over 24 hours for 36 office hypertensive patients and 33 normotensive controls.
- Conventional and rhythm analysis of ABPM data were performed.
- Urinary catecholamine excretion (noradrenaline, dopamine) was measured as an indicator of sympathetic nervous system activity.
Main Results:
- Office hypertensives exhibited significantly higher clinic blood pressure (146/97 mmHg) versus normotensives (128/81 mmHg).
- ABPM showed no differences in 24-hour, daytime, or nighttime mean values, but office hypertensives had greater blood pressure amplitude (higher max, lower min).
- Office hypertensives displayed a significantly greater early morning blood pressure rise and increased daytime urinary excretion of noradrenaline and dopamine.
Conclusions:
- Office hypertension is associated with abnormal blood pressure regulation, including increased amplitude and a pronounced early morning rise, indicative of heightened sympathetic activation.
- These findings suggest office hypertension represents an early stage of hypertensive disease, preceding established hypertension.
- The study highlights the importance of ambulatory blood pressure monitoring for identifying abnormal blood pressure regulation patterns.
Abstract:
BACKGROUND: The percentage of patients with office or white-coat hypertension has been reported in international studies to be 20-30% of the hypertensive population. These patients can be identified and distinguished from patients with established hypertension by ambulatory blood pressure monitoring (ABPM) or self-measurement. There is still no satisfactory explanation for the phenomenon of 'office hypertension' and there are no data available to show how the blood pressure behaviour of office hypertensives differs from that of normotensive subjects away from the physician's office or clinic environment. OBJECTIVE: To investigate the blood pressure behaviour of patients with office hypertension away from the clinical setting over a 24 h period and to compare it with that of normotensive subjects. DESIGN AND METHODS: The blood pressure and heart rate of 36 patients with office hyhpertension and 33 normotensive subjects matched for age and sex were measured in a hypertension outpatient clinic and over 24 h using ABPM. The ambulatory data were subjected both to conventional and to modern rhythm analysis. Urinary catecholamine excretion was measured as a marker of sympathetic activity. RESULTS: In the clinic, the patients with office hypertension had significantly (P < 0.01) higher blood pressure values (146/97 mmHg) than did the normotensive controls (128/81 mmHg). The conventional analysis as well as the rhythm analysis of the ABPM data revealed no difference between the two groups with respect to the 24 h, daytime or night-time mean values and SD. However, the rhythm analysis showed a higher maximum and a lower minimum value for systolic and diastolic blood pressures in the patients with office hypertension, resulting in a greater amplitude both of systolic and of diastolic blood pressure due to a significantly (P < 0.005 and P < 0.05) higher maximum minus minimum value (38/32 mmHg) compared with those of normotensive controls (29/28 mmHg). The early morning rise in systolic and diastolic blood pressures was significantly (P < 0.008 and P < 0.03) greater in the patients with office hypertension (11/9 versus 7/7 mmHg) and intersected the curve of the normotensive controls at approximately 0600 h. No significant differences in heart rate at any time were observed between the groups. The urinary excretion of noradrenaline and dopamine was significantly (P < 0.01 and P < 0.05) increased during daytime for the office hypertensives. CONCLUSION: Patients with office hypertension, who by definition do not yet have established hypertension, already exhibit abnormal regulation both of systolic and of diastolic blood pressure during the morning period and daytime, with a significantly greater early morning rise compared with normotensive subjects and a greater blood pressure amplitude (amplitude hypertension) due to lower blood pressure during night-time and higher blood pressure during the day with increased sympathetic activation. Office hypertension seems to be the earliest manifestation of hypertension.