title: The association of night-time systolic blood pressure with ultrasound markers of subclinical cardiac and vascular disease.
abstract: BACKGROUND
  The aim of this study was to examine the association of night-time systolic blood pressure (BP) with subclinical cardiac dysfunction measured by global longitudinal strain (GLS) and subclinical vascular damage measured by carotid intima-media thickness (CIMT) and carotid plaques.
  
  
  METHODS
  GLS was measured by speckle-tracking analysis of echocardiogram images. CIMT was measured at the distal 1 cm of the common carotid artery. The presence of carotid plaques was recorded. Philips QLAB cardiac and vascular ultrasound quantification software was used for analysis. The association of night-time systolic BP with GLS, CIMT and carotid plaques was assessed using linear and logistic regression.
  
  
  RESULTS
  Fifty (response rate 63%) individuals took part in this study. In univariable models, night-time systolic BP was significantly associated with GLS [β coefficient 0.85 for every 10 mmHg increase, 95% confidence interval (CI): 0.3-1.4] and carotid plaques (odds ratio 1.9 for every 10 mmHg increase, 95% CI: 1.1-3.2). Univariable analysis of daytime systolic BP did not show any statistically significant associations. In age-adjusted and sex-adjusted models, the association for night-time systolic BP and GLS remained significant (β coefficient 0.68 for every 10 mmHg increase, 95% CI: 0.1-1.3). The association for carotid plaques was no longer statistically significant. In multivariable models, findings were diminished.
  
  
  CONCLUSIONS
  Our results suggest a trend towards an association between night-time systolic BP and subclinical cardiac and vascular disease. When assessing ambulatory blood pressure monitoring results, the absolute night-time systolic BP seems to be a better prognostic parameter than daytime systolic BP, but ultimately a large randomised controlled trial involving chronotherapy is necessary to fully address this.
authors.affiliation: aDepartment of Epidemiology and Public Health, University College Cork bDepartment of Cardiology, Cork University Hospital, Cork cDepartment of Geriatrics, Connolly Hospital, Blanchardstown, Ireland dDepartment of Cardiology, Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, UK.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: O'Flynn
authors.forename: Emily
authors.initials: E
authors.lastname: Ho
authors.forename: Eamon
authors.initials: E
authors.lastname: Dolan
authors.forename: Ronan J
authors.initials: RJ
authors.lastname: Curtin
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Kearney
mesh_terms: D000368:Aged; D001794:Blood Pressure; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D059168:Carotid Intima-Media Thickness; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging / Q000503:physiopathology