title: A novel measure of the power of the morning blood pressure surge from ambulatory blood pressure recordings.
abstract: BACKGROUND
  We defined a new measure of the morning blood pressure (BP) surge (MBPS) that is derived by the product of the rate of morning rise (RoR) and the amplitude (day-night difference) giving an effective "Power" of the BP rise (BP(Power)). We applied this method to determine whether morning BP(Power) is different in hypertensives compared to normotensives, males compared to females or altered by antihypertensive treatment.
  
  
  METHODS
  BP(Power), RoR, and day-night amplitude were calculated using a double logistic fit of 691 ambulatory recordings.
  
  
  RESULTS
  Ambulatory recordings from untreated male and female subjects showed that upper quartile (distributed by day BP, n = 100) had a 92% greater BP(Power) (P < 0.001) than the lower quartile subjects (n = 100) due to both a faster RoR and greater amplitude. Males had a 29% greater BP(Power) than females (P = 0.003). Untreated hypertensives and white coat hypertensives showed a greater morning BP(Power) (+158% and +86%, respectively) compared to matched normotensives. Subjects taking calcium channel blockers and diuretics alone or in combination with angiotensin receptor blockers had lower morning BP(Power) than those on angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor antagonists alone.
  
  
  CONCLUSIONS
  A new measure of the MBPS, BP(Power) which is based on a mathematical estimate of the rate and amplitude of the rise, is higher in hypertensives, white coat hypertensives, and is modifiable by some specific antihypertensive therapies suggests that it may be theoretically useful to highlight those subjects at greatest risk of cardiovascular events and for determining the most benefit of antihypertensive therapy.
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Australia. Geoff.Head@baker.edu.au
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Head
authors.forename: Kanella
authors.initials: K
authors.lastname: Chatzivlastou
authors.forename: Elena V
authors.initials: EV
authors.lastname: Lukoshkova
authors.forename: Garry L
authors.initials: GL
authors.lastname: Jennings
authors.forename: Chris M
authors.initials: CM
authors.lastname: Reid
mesh_terms: D000465:Algorithms; D047228:Angiotensin II Type 1 Receptor Blockers / Q000627:therapeutic use; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000503:physiopathology; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D004232:Diuretics / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D018570:Risk Assessment; D012727:Sex Characteristics
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D004232:Diuretics