title: Is the area under blood pressure curve the best parameter to evaluate 24-h ambulatory blood pressure monitoring data?
abstract: BACKGROUND
  Ambulatory blood pressure monitoring (ABPM) provides relevant data about blood pressure over a 24-h period. The analysis of parameters to determine the blood pressure profile from these data is of great importance.
  
  
  OBJECTIVE
  To calculate areas under systolic and diastolic blood pressure curves (SBP-AUC/DBP-AUC) and compare with systolic and diastolic blood pressure load (SBPL/DBPL) and 24-h systolic and diastolic blood pressure (24-h SBP/24-h DBP) in order to determine which provides the best correlation with left ventricular mass index (LVMI).
  
  
  METHODS
  ABPM measurements (1143 individuals) were analyzed to obtain 24-h SBP/24-h DBP, SBPL/DBPL, and SBP-AUC/ DBP-AUC, using Spacelabs (90207) and CardioSistemas devices. Left ventricular mass was determined using an echocardiograph HP Sonos 5500 and LVMI was calculated.
  
  
  RESULTS
  The correlations between all possible pairs within the group 24-h SBP/SBPL/SBP-AUC and 24-h DBP/DBPL/DBP-AUC were high and statistically significant. The correlations between 24-h SBP/24-h DBP and SBP-AUC/DBP-AUC with SBPL/DBPL close to 100%, were lower than those mentioned above. The correlations of the parameters obtained by ABPM with LVMI were also high and statistically significant, except for blood pressure load between 90 and 100%, and for 24-h SBP of 135 mmHg or less and SBPL higher than 50%.
  
  
  CONCLUSIONS
  SBPL/DBPL and SBP-AUC/DBP-AUC can be used for the evaluation of ABPM data owing to the strong correlation with 24-h SBP/24-h DBP and with LVMI, except when SBPL is close to 100% or 24-h SBP is below 135 mmHg but SBPL is above 50%. SBP-AUC/DBP-AUC, however, are a better alternative because they do not have the limitations of blood pressure load or even of 24-h blood pressure present.
authors.affiliation: Department of Internal Medicine, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil. fernando.nobre@uol.com.br
authors.forename: Fernando
authors.initials: F
authors.lastname: Nobre
authors.forename: Décio
authors.initials: D
authors.lastname: Mion
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods* / Q000592:standards; D003971:Diastole / Q000502:physiology; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular; D008297:Male; D008875:Middle Aged; D013599:Systole / Q000502:physiology