Exploiting the ambulatory blood pressure monitoring via chronobiometric and chaosbiometric methods for a more exhaustive diagnostic approach to arterial hypertension

• Published in: Clinica terapeutica Vol. 159; no. 6; p. e1
• Main Author: Cugini, P
• Format: Journal Article
• Language: English
• Published: Italy 01-11-2008
• Subjects: Algorithms; Biometry - methods; Blood Pressure Monitoring, Ambulatory - methods; Blood Pressure Monitoring, Ambulatory - statistics & numerical data; Chronobiology Phenomena; Circadian Rhythm - physiology; Fractals; Humans; Hypertension - diagnosis; Hypertension - physiopathology; Microcomputers; Nonlinear Dynamics; Software
• ISSN: 1972-6007

Presently, the ambulatory (A) blood (B) pressure (P) monitoring (M) is mainly used for diagnosing arterial hypertension (AH) in some special clinical conditions in which the causal sphygmomanometry appears not to be enough exhaustive. However, it must be pointed out that the actual approach to ABPM is almost simplistic, only consisting in a biometric analysis of discrete raw temporal values for systolic (S) and diastolic (D) BP and heart rate (HR). It must be stressed that BP and HR are hemodynamic variables characterized by a well established circadian rhythm (C) in their 24-h physiological values. Therefore, an appropriate chronobiometric approach, via Single Cosinor method, can improve the diagnostic value, its optimal oscillatory curve reducing all the biometric information to three parameters, i.e., MESOR (M, mean level of oscillation), Amplitude (A, extent of oscillation from M) and Acrophase (phi, timing of A with respect to local midnight). Accordingly, one can detect whether the BP CR is still manifest, as it is in essential hypertension (EH), or altered , as it is in secondary hypertension (SH). Therefore, by using the discriminant analysis for the three multivariate parameters, M, A, phi, of the BP cosine curve, one can statistically predict whether a new monitored hypertensive patient has a significant probability to be affected by EH or SH. Interestingly, by applying a further chronobiometric integration analysis, i.e., the Cosint analysis, it is possible to estimate the area under the BP oscillatory curve, for calculating the overall, diurnal, nocturnal, hourly pressure load (Baric Impact, BI) in terms respectively of mm2 Hg/24-h, mm2 Hg/16-h, mm2Hg/8-h, mm2 Hg/1-h. By comparing the overall BI of the new monitored hypertensive patient to its upper reference limit, one can estimate how much is the Baric Excess (Hyperbaric Impact, HI) caused by the personal hypertensive regimen. Finally, by using the chaos method of fractal interpolation to BP 24-h values, it is possible to establish whether or not the monitored hypertensive subject is presumably at risk of unpredictable high BP values (presumable risk of hypertensive crisis).