Aortic Pulse Pressure Does Not Adequately Index Cardiovascular Risk Factor-Related Changes in Aortic Stiffness and Forward Wave Pressure

Abstract

Background: Through the impact of conventional risk factors on arteries, several changes in aortic function contribute to cardiovascular events. It is nevertheless uncertain whether these effects are accurately reflected by changes in central aortic pulse pressure (PPc). We, therefore, aimed to determine the extent to which relations between modifiable risk factors and aortic function translate into increases in PPc. Methods: In 1,232 black South Africans from the South West Township (SOWETO) of Johannesburg, we determined risk factors and aortic function from carotid-femoral pulse wave velocity (PWV), aortic PPc, forward wave pressures (Pf ), and reflected (backward) wave pressures (Pb) (applanation tonometry and SphygmoCor software). Results: With adjustments for alternative risk factors and distending pressure (mean arterial pressure (MAP)), diabetes mellitus (treatment or HbA1c > 6.5%, n = 151) was associated with an increased PWV (7.10 ± 2.09 vs. 6.17 ± 2.00 m/s, P < 0.0001), and Pf (26 ± 8 vs. 24 ± 8 mm Hg, P < 0.005), but neither brachial PP (46 ± 14 vs. 45 ± 13, P = 0.19), PPc (36 ± 12 vs. 35 ± 11 mm Hg, P = 0.48), nor Pb (17 ± 6 vs. 17 ± 6 mm Hg, P = 0.83). Moreover, independent of alternative risk factors and MAP, uncontrolled hypertension (office blood pressure > 140/90 mm Hg, n = 433) was associated with an increased Pf (26 ± 12 vs. 24 ± 10 mm Hg, P < 0.01), but not with changes in brachial PP (45 ± 19 vs. 44 ± 17, P = 0.75), PPc (35 ± 16 vs. 35 ± 15 mm Hg, P = 0.93), or Pb (18 ± 8 vs. 17 ± 8 mm Hg, P = 0.46). Conclusions: Neither brachial nor aortic PP are adequate indexes of relations between the modifiable conventional risk factors, uncontrolled hypertension or diabetes mellitus, and risk-related aortic functional changes.