24-hour ambulatory monitoring of arterial blood pressure and the sympathetic nervous system in hypertensive smokers
Gambini, G.; Di Cato, L.; Pinchi, G.; Valori, C.
Giornale Italiano di Cardiologia 27(11): 1153-1157
1997
ISSN/ISBN: 0046-5968 PMID: 9463059 Document Number: 478854
To test the hypothesis that heavy smoking may interfere with the variation in ambulatory blood pressure (ABP) and sympathetic nervous system in essential hypertension. We compared the office and 24-hour ABP of 48 untreated hypertensive smokers (> 20 cigarettes daily) with 90 non-smoking hypertensives matched for age, sex and body mass index. ABP was recorded using fully automatic SpaceLabs 90,207 units set to take a measurement every 15 minutes during the day (7.00 a.m.-10.00 p.m.) and every 20 minutes during the night (10.00 p.m.-7.00 a.m.). Urine collection for urinary sodium, potassium, epinephrine and norepinephrine excretion was performed during the 24-hour period of ABP monitoring. Catecholamines were measured by high pressure liquid chromatography. The office blood pressure readings of the smoking and non-smoking groups were 156.7/103.4 and 156.5/103.9 mmHg respectively. During the day-time period, ambulatory systolic and diastolic blood pressure was significantly higher in the smokers (146 +/- 12 vs 140.4 +/- 13 mmHg, p < 0.02; 96.4 +/- 8.15 vs 93.1 +/- 10 mmHg, p < 0.05 respectively). This difference was greater among patients under the age of 50 (145.9 +/- 13 vs 136.6 +/- 11 mmHg, p < 0.001 and 97.1 +/- 8.7 vs 92.3 +/- 9.9 mmHg, p < 0.02). Blood pressure during the night-time period did not differ between the two groups (130.5/81.3 vs 126.3/79.5). No differences were detected among the groups as far as urinary catecholamine excretion is concerned. Our data suggest that among hypertensive subjects, smokers maintain a higher day-time ambulatory systolic and diastolic blood pressure than non-smokers, particularly in the younger patients, even though casual blood pressure is similar.