Distinct Contribution of Systemic Blood Flow to Hypertension in an African Population Across the Adult Lifespan

Hypertension. 2020 Aug;76(2):410-419. doi: 10.1161/HYPERTENSIONAHA.120.14925. Epub 2020 Jun 22.

Abstract

Although hypertension in groups of African ancestry is volume-dependent, the relative impact of systemic flow (stroke volume, peak aortic flow [Q]) versus vascular mechanisms (systemic vascular resistance, aortic characteristic impedance [Zc], total arterial compliance) components of arterial load has not been evaluated across the adult age range. In participants of African ancestry (n=824, age=16-99 years, 68.3% female), using central arterial pressure and aortic velocity and diameter measurements in the outflow tract, we determined the hemodynamic correlates of age-related increases in blood pressure. Strong independent positive relations between age and stroke volume or peak aortic Q were noted (P<0.0001), effects associated with ventricular end diastolic volume and aldosterone-to-renin ratios. Age-related increases in mean arterial pressure were associated with stroke volume and not systemic vascular resistance. Although age-Q relations began from early adulthood, initially an inverse association between age and aortic Zc (P<0.0001) driven by increments in aortic root diameter (P<0.0001) prevented an enhanced systolic blood pressure and pulse pressure. When Zc began to positively relate to age (P<0.0001), age-Q relations translated into increases in forward wave pressures and hence systolic blood pressure and pulse pressure. Age relations with pulse pressure were as strongly determined by Q as by Zc or total arterial compliance (0.027±0.001 versus 0.028±0.001 and 0.032±0.003 mm Hg per yearly increase in pulse pressure produced by Q, Zc, and total arterial compliance; P<0.0001). Uncontrolled hypertension (confirmed with 24-hour blood pressure) was determined more by Q, Zc, and total arterial compliance than by increases in systemic vascular resistance (P<0.0005 for comparison). In conclusion, relationships between age and systemic blood flow contribute markedly to hypertension in groups of African origins.

Keywords: aldosterone; blood pressure; compliance; stroke volume; vascular resistance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Aorta / physiopathology
  • Arteries / physiopathology
  • Black or African American
  • Blood Pressure / physiology*
  • Female
  • Hemodynamics / physiology*
  • Humans
  • Hypertension / physiopathology*
  • Longevity
  • Male
  • Middle Aged
  • Stroke Volume / physiology*
  • Vascular Resistance / physiology*
  • Vascular Stiffness / physiology
  • Young Adult