title: [Determination of the "presumptive risk" of hypertensive crisis with fractal interpolation of 24-hour arterial pressure. II: study with secondary hypertensive patients].
abstract: OBJECTIVE
  The present study applies the "fractal interpolation" (FI) to 24-h blood pressure nonivasively and ambulatorily monitored over a day-night period in secondary hypertensives. The purpose is the evaluation of the prevalence for a "presumptive risk" (PR) of hypertensive crisis.
  
  
  METHODS
  The study was carried out in 108 cases of secondary hypertension, who were non-invasively and ambulatorily monitored for their 24-h blood pressure values. The FI was applied to the time-qualified values of the mean arterial pressure.
  
  
  RESULTS
  The PR of hypertensive crisis was found in 11% of the investigated secondary hypertensive patients. Such a risk shows a not significant prevalence 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. Additionally, a not 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 associated with the dipping/non-dipping phenomenon as well as the circadian rhythmicity of blood pressure. Its occurrence in secondary hypertensives is essentially related to the disorder that is detectable in blood pressure non-linear variability. Therefore, such a risk may be caused by neurovegetative mechanisms which notoriously confer a non-linear chaotic variability to 24-h blood pressure pattern.
authors.affiliation: Dipartimento di Scienze Cliniche, Università di Roma La Sapienza, Roma, Italia.
authors.forename: P
authors.initials: P
authors.lastname: Cugini
authors.forename: R
authors.initials: R
authors.lastname: De Rosa
authors.forename: S
authors.initials: S
authors.lastname: Coda
authors.forename: G P
authors.initials: GP
authors.lastname: De Francesco
authors.forename: S
authors.initials: S
authors.lastname: Fontana
authors.forename: A M
authors.initials: AM
authors.lastname: Pellegrino
mesh_terms: D000328:Adult; D000368:Aged; D002940:Circadian Rhythm; D005260:Female; D017709:Fractals; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment