Alberto Maronati

A new method for assessing 24-h blood pressure variability after excluding the contribution of nocturnal blood pressure fall.

Objectives To assess quantitatively the relationship between nocturnal blood pressure (BP) fall and 24-h BP variability; to propose a new method for computing 24-h BP variability, devoid of the contribution from nocturnal BP fall; and to verify the clinical value of this method. Methods and results We analysed 3863 ambulatory BP recordings, and computed: (1) the standard deviation (SD) of 24-h BP directly from all individual readings and as a weighted mean of daytime and night-time SD (wSD); and (2) the size of nocturnal BP fall. Left ventricular mass index (LVMI) was assessed by echocardiography in 339 of the patients. The 24-h SD of BP was significantly greater than the 24-h wSD. Nocturnal BP fall was strongly and directly related to 24-h SD, the relationship with 24-h wSD being much weaker and inverse. The difference between SD and wSD was almost exclusively determined by the size of nocturnal BP fall. wSD of systolic BP was significantly related to LVMI, while 24-h SD was not. Conclusion Conventional 24-h SD of BP is markedly influenced by nocturnal BP fall. The weighted 24-h SD of BP removes the mathematical interference from night-time BP fall and correlates better with end-organ damage, therefore it may be considered as a simple index of 24-h BP variability superior to conventional 24-h SD.

Assessment of long-term antihypertensive treatment by clinic and ambulatory blood pressure: Data from the European Lacidipine Study on Atherosclerosis

Objectives Information on the features of long-term modifications of clinic and 24-h ambulatory blood pressure (ABP) by treatment is limited. The present study aimed to address this issue. Methods Ambulatory BP monitoring and clinic BP (CBP) measurements were performed at baseline and at yearly intervals over a 4-year follow-up period in 1523 hypertensives (56.1 ± 7.6 years) randomized to treatment with lacidipine or atenolol in the European Lacidipine Study on Atherosclerosis (ELSA). Results CBP was always greater than ABP, while reductions in all BP values (greater for CBP than for ABP) were on average maintained throughout 4 years, CBP changes showing limited relationship with ABP changes (r = 0.14–0.27). BP reductions by treatment during daytime and night-time were correlated (r = 0.63–0.73). BP normalization was achieved in a greater percentage of patients for CBP (41.7%) than for ABP (25.3%), with systolic BP control being always less common than diastolic BP control. BP normalization was more frequent at single yearly visits than throughout the 4 years. Twenty-four-hour BP variability was reduced by treatment over 4 years in absolute but not in normalized units. Conclusions The present study provides the best evidence available on long-term effect of antihypertensive treatment on both ABP and CBP. On average, ABP was sustainedly reduced by treatment throughout the follow-up period, but 24-h BP was more difficult to control than CBP. In several patients, ABP control was unstable between visits, the percentage of patients under control over 4 years being much less than that of those controlled at each year. Treatment induced a reduction in absolute but not in normalized BP variability estimates. This has clinical implications because of the prognostic importance of ABP mean values and variability.

The impact of the degree of obesity on the discrepancies between office and ambulatory blood pressure values in youth.

Objectives Obesity is an increasingly frequent problem among children and adolescents, and may lead to blood pressure (BP) increase. The aim of the present study was to assess the prevalence of hypertension, white-coat and masked hypertension in obese adolescents making systematic use of both office BP and 24-h ambulatory BP measurement. The impact of different degrees of obesity on BP and heart rate variability was also investigated. Methods Office and ambulatory BP were obtained in 285 overweight and obese Caucasian adolescents (11–18 years old) and in 180 age- and sex-matched controls. The extent of obesity was quantified using body mass index z score. Results A significant positive relationship between body mass index z score and both office and ambulatory systolic BP was found after adjusting for age and height in both boys and girls. Obese youths had not only higher BP levels, but also higher BP variability compared with controls. Among obese youths, 20.8% had abnormal BP conditions, 6.6% were white-coat hypertensives, 9.2% were masked hypertensives and 5% were sustained hypertensives. Conclusions The prevalence of these abnormal BP conditions, which can be identified thanks to ambulatory BP monitoring, further emphasizes the usefulness of this diagnostic tool in obese youths.

Assessment of overall blood pressure variability and its different components

Blood pressure (BP) is characterized by continuous fluctuations, including fast changes lasting only a few seconds as well as slower and more prolonged variations, with a time constant of minutes or hours. Assessing the relative contribution of these different components to overall blood pressure variance is now possible through a number of mathematical approaches, either in the time or in the frequency domain (spectral analysis). Due to its complex nature, a precise and detailed assessment of blood pressure variability can be obtained only from the analysis of continuous, beat-by-beat, blood pressure recordings. Some information, however, can also be derived from analysis of discontinuous blood pressure tracings, such as those commonly performed in a clinical setting. This would require that attention is paid both to the quality of the recordings and to the selection of suitable analysis methods that should cope with the discontinuous nature of the measurements to be processed and to their intrinsic low sampling frequency.