Assessment of Arterial Stiffness by 24-Hour Ambulatory Blood Pressure Monitoring in Nocturnal Hypertensive or Normotensive Subjects

Abstract

Background: Nocturnal hypertension, male gender, age and arterial stiffness are important risk factors for cardiovascular morbidity and mortality. The objective of this study was to assess arterial stiffness in nocturnal hypertensive or normotensive men and women >40 years of age. Methods: Twenty-four-hour ambulatory blood pressure monitoring was performed in 144 men and 137 women. Eighty-eight subjects were between 40 and 49 years old (53% men), 98 were between 50 and 59 years old (55% men) and 95 were >60 years old (45% men). They were classified as nocturnal hypertensive if their average night systolic blood pressure and/or diastolic blood pressure was >120/70 mm/Hg. Arterial stiffness was assessed by the Ambulatory Arterial Stiffness Index (AASI), which is calculated as 1 minus the slope of diastolic on systolic blood pressure during the 24-hour recording period. Results were analyzed by analysis of covariance and were adjusted for 24-hour mean arterial pressure, the presence of antihypertensive treatment, height and heart rate. Results: Women showed a higher AASI compared to men, independently of age. In men, the AASI increased with age, being higher in nocturnal hypertensive than in nocturnal normotensive subjects, independently of age. Nocturnal hypertensive women showed higher AASI values than their respective nocturnal normotensive controls in the 50- to 59-year and >60-year age groups only. Conclusion: The results show that arterial stiffness is higher among nocturnal hypertensive subjects, especially in women >50 years old.