The current standard for arterial stiffness assessment, aortic pulse wave velocity (aPWV), is measured at diastolic pressure. Arterial stiffness, however, is pressure dependent. At the carotid artery level, the degree of this dependency can be quantified as the difference (ΔPWV) between systolic and diastolic (cPWVd) carotid pulse wave velocity. Biomechanically, a greater ΔPWV implies greater increases in left ventricular afterload with physical activity. Therefore, we hypothesized, that ΔPWV is more strongly associated with left ventricular mass index (LVMI) than aPWV and cPWVd.
In 1776 healthy individuals from the Asklepios cohort (age 35–55 years), ΔPWV was obtained from combined carotid artery ultrasound and tonometry recordings. Multiple linear regression analysis was performed to investigate the associations of ΔPWV, cPWVd and aPWV with LVMI, adjusting for age, sex, mean blood pressure (MBP), central pulse pressure, and other possible confounders.
ΔPWV was 2.4 ± 1.2 m/s (mean ± SD), ranging from 0.8 m/s, indicating almost constant arterial stiffness over the cardiac cycle, to 4.4 m/s, reflecting substantial pressure dependency. ΔPWV was significantly associated with LVMI (β of 2.46 g/m1.7 per m/s, P < 0.001), even after full adjustment (β of 0.56 g/m1.7 per m/s, P = 0.03). cPWVd and aPWV had clear crude associations with LVMI (P < 0.001), but lost significance after adjustment (β of −0.48 and −0.33 g/m1.7 per m/s, with P = 0.11 and 0.2, respectively).
The change in arterial stiffness over the cardiac cycle, rather than diastolic stiffness, is independently associated with LVMI in healthy middle-aged individuals. Therefore, the pressure dependency of arterial stiffness should be considered in cardiovascular risk assessment.
aDepartment of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, The Netherlands
bIBiTech-bioMMeda, Ghent University
cDepartment of Clinical Pharmacology, Ghent University Hospital
dDepartment of Cardiology, Ghent University Hospital, Ghent, Belgium
eDepartment of Internal Medicine
fDepartment of Clinical Epidemiology and Medical Technology Assessment
gDepartment of Physiology, CARIM School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, The Netherlands
Correspondence to Koen D. Reesink, PhD, Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, P.O. Box 616, 6200 MD Maastricht, The Netherlands. Tel: +31 43 388 1668; e-mail: firstname.lastname@example.org
Abbreviations: ΔPWV, systolic–diastolic difference in carotid pulse wave velocity; A, carotid artery cross-sectional area; aPWV, aortic pulse wave velocity; cPWV, carotid pulse wave velocity; cPWVd, diastolic carotid pulse wave velocity; cPWVs, systolic carotid pulse wave velocity; D, diameter; LV, left ventricle; LVMI, left ventricular mass index; MBP, mean blood pressure; p, carotid artery pressure; PP/cPP, pulse pressure/central pulse pressure
Received 30 June, 2011
Revised 22 September, 2011
Accepted 18 October, 2011