[Individualization of the "presumptive risk" of hypertensive crisis using fractals interpolation of the 24-hour arterial pressure. Study of patients with essential hypertension].
OBJECTIVE
The present study applies the "fractal interpolation" (FI) to blood pressure that was nonivasively and ambulatorily monitored over a day-night period in essential hypertensives. The purpose is the identification of cases who are at a "presumptive risk" (PR) for hypertensive crisis.


METHODS
The investigation was performed on 380 ascertained cases of essential hypertension, who underwent a non-invasive ambulatory monitoring of 24-h blood pressure. The FI was applied to the ambulatory mean arterial pressure.


RESULTS
The FI showed that the PR of hypertensive crisis can be found in 14% of the investigated essential hypertensive patients. Such a risk is not significantly higher in dippers as compared to non-dippers, and in those who showed a significant blood pressure circadian rhythm as compared to those who showed the blood pressure circadian rhythm to be abolished. Furthermore, no significant difference was found between the cases "at risk" and "not at risk" as far as the spectrum of harmonic formants of the 24-h blood pressure pattern is concerned.


CONCLUSIONS
The PR of hypertensive crisis is not correlated to the dipping/nondipping condition, circadian rhythmicity and complex harmonic structure of 24-h blood pressure pattern. Its occurrence depends essentially from the disorder that is detectable in 24-h blood pressure pattern. Therefore, such a PR in essential hypertensives may be attributed to the mechanisms, likely neurovegetative, which confer a non-linear chaotic variability to 24-h blood pressure values.
Cugini
P
P
Dipartimento di Scienze Cliniche, Università di Roma La Sapienza, Roma, Italia.
De Rosa
R
R
Coda
S
S
De Francesco
G P
GP
Fontana
S
S
Pellegrino
A M
AM
D000328:Adult; D000368:Aged; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D005260:Female; D017709:Fractals; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D017711:Nonlinear Dynamics; D012307:Risk Factors; D013997:Time Factors