title: Clinical relevance of nighttime blood pressure and of daytime blood pressure variability.
abstract: BACKGROUND
  The purpose of this study was to assess whether hypertensive target organ damage is related to average nighttime blood pressure (BP) and to BP variability.
  
  
  METHODS
  Sixty-seven normotensive subjects and 171 borderline, 309 mild, 140 moderate, and 41 severe hypertensive patients were studied with noninvasive ambulatory BP monitoring. Each subject was assigned a target organ damage score of 0 to 5 on the basis of funduscopic changes and degree of left ventricular hypertrophy calculated from electrocardiogram and chest roentgenogram.
  
  
  RESULTS
  When the 728 subjects were subdivided into five classes of increasing daytime BP, in each class a significantly higher degree of target organ damage was present in the subjects with higher nighttime diastolic BP. A similar, although nonsignificant, trend was observed in the subjects with higher nighttime systolic BP. In particular, higher nighttime BP levels were accompanied by a more severe degree of left ventricular hypertrophy. As for variability, subjects with higher daytime systolic BP SD, but not with higher daytime diastolic SD, displayed a more severe degree of target organ damage; this was accounted for by a higher degree of retinal abnormalities. The association between target organ damage and systolic BP SD was present both in men and women, while that with nighttime BP was present only in men. No relationship was found between degree of cardiovascular complications and peaks of pressure.
  
  
  CONCLUSIONS
  These results suggest that a reduced day-night BP difference and an increased daytime BP variability, evaluated as the SD, are associated with a higher degree of hypertensive cardiovascular complications. Whether this BP profile is the cause or the consequence of target organ damage remains to be established.
authors.affiliation: First Medical Clinic, University of Padua, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Palatini
authors.forename: M
authors.initials: M
authors.lastname: Penzo
authors.forename: A
authors.initials: A
authors.lastname: Racioppa
authors.forename: E
authors.initials: E
authors.lastname: Zugno
authors.forename: G
authors.initials: G
authors.lastname: Guzzardi
authors.forename: M
authors.initials: M
authors.lastname: Anaclerio
authors.forename: A C
authors.initials: AC
authors.lastname: Pessina
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D015924:Blood Pressure Monitors; D006332:Cardiomegaly / Q000175:diagnosis / Q000209:etiology*; D002940:Circadian Rhythm / Q000502:physiology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000503:physiopathology; D008297:Male; D009887:Ophthalmoscopy; D012164:Retinal Diseases / Q000175:diagnosis / Q000209:etiology; D012171:Retinal Vessels