Aortic-Femoral Stiffness Gradient and Cardiovascular Risk in Older Adults

Abstract

Background: The aortic-femoral arterial stiffness gradient, calculated as the ratio of lower-limb pulse-wave velocity (PWV) to central (aortic) PWV, is a promising tool for assessing cardiovascular disease (CVD) risk, but whether it predicts incident CVD is unknown.

Methods: We examined the association of the aortic-femoral arterial stiffness gradient measures carotid-femoral stiffness gradient (femoral-ankle PWV divided by carotid-femoral PWV) and the heart-femoral stiffness gradient (femoral-ankle PWV divided by heart-femoral PWV), as well as PWV, with incident CVD (coronary disease, stroke, and heart failure) and all-cause mortality among 3109 participants of the Atherosclerosis Risk in Communities Study cohort (age, 75±5 years; carotid-femoral PWV, 11.5±3.0 m/s), free of CVD. Cox regression was used to estimate hazard ratios (HR) and 95% CIs.

Results: Over a median 7.4-year follow-up, there were 322 cases of incident CVD and 410 deaths. In fully adjusted models, only top quartiles of carotid-femoral stiffness gradient (quartile 4: HR, 1.43 [95% CI, 1.03-1.97]; and quartile 3: HR, 1.49 [95% CI, 1.08-2.05]) and heart-femoral stiffness gradient (quartile 4: HR, 1.77 [95% CI, 1.27-2.48]; and quartile 3: HR, 1.41 [95% CI, 1.00-2.00]) were significantly associated with a greater risk of incident CVD. Only high aortic stiffness in combination with low lower-limb stiffness was significantly associated with incident CVD (HR, 1.46 [95% CI, 1.06-2.02]) compared with the referent low aortic stiffness and high lower-limb stiffness. No PWVs were significantly associated with incident CVD. No exposures were associated with all-cause mortality.

Conclusions: The aortic-femoral arterial stiffness gradient may enhance CVD risk assessment in older adults in whom the predictive capacity of traditional risk factors and PWV are attenuated.

Keywords: arterial stiffness; cardiovascular diseases; heart failure; pulse wave velocity; risk factors; stroke.

Figure 1.

Cumulative probability of cardiovascular events by quartiles of carotid-femoral pulse wave velocity (A), carotid-femoral arterial stiffness gradient (B), heart-femoral pulse wave velocity (C), heart-femoral arterial stiffness gradient (D), and femoral-ankle PWV (E). Log-rank statistic was used to compare survival distributions between quartiles.

Figure 2.

Associations of pulse wave velocity and aortic-femoral arterial stiffness gradient with risk of cardiovascular events. Abbreviations: Carotid-femoral pulse-wave velocity; hfPWV, heart-femoral pulse-wave velocity; faPWV, femoral-ankle pulse-wave velocity; cfSG, carotid-femoral arterial stiffness gradient; hfSG, heart-femoral arterial stiffness gradient; HR, hazard ratio; 95% CI, 95% confidence interval; Q1, quartile 1; Q2, quartile 2, Q3; quartile 3; Q4, quartile 4. Model adjustments: age, sex, race-centre, education, current smoking status, history of diabetes, mean arterial pressure, antihypertensive medication, total cholesterol, high-density lipoprotein cholesterol, and heart rate. cfPWV range (m/s): Q1, <9.4; Q2, 9.4 to 11.0; Q3, 11.0 to 13.1, Q4 >13.1. hfPWV range (m/s): Q1, <9.9; Q2, 9.9 to 11.2; Q3, 11.2 to 12.9, Q4 >12.9. faPWV range (m/s): Q1, <9.9; Q2, 9.9 to 10.9; Q3, 10.9 to 12.0, Q4 >12.0. cfSG range: Q1, >1.18; Q2, 1.18 to 1.00; Q3, >0.99 to 0.82, Q4 <0.82. hfSG range: Q1, >1.13; Q2, 1.13 to 0.97; Q3, >0.97 to 0.83, Q4 <0.83.

Figure 3.

Cumulative probability of all-cause mortality by quartiles of carotid-femoral pulse wave velocity (A), carotid-femoral arterial stiffness gradient (B), heart-femoral pulse wave velocity (C), heart-femoral arterial stiffness gradient (D), and femoral-ankle PWV (E). Log-rank statistic was used to compare survival distributions between quartiles.

Figure 4.

Associations of pulse wave velocity and aortic-femoral arterial stiffness gradient measures with risk of all-cause mortality. Abbreviations: Carotid-femoral pulse-wave velocity; hfPWV, heart-femoral pulse-wave velocity; faPWV, femoral-ankle pulse-wave velocity; cfSG, carotid-femoral arterial stiffness gradient; hfSG, heart-femoral arterial stiffness gradient; HR, hazard ratio; 95% CI, 95% confidence interval; Q1, quartile 1; Q2, quartile 2, Q3; quartile 3; Q4, quartile 4. Model adjustments: age, sex, race-centre, education, current smoking status, history of diabetes, mean arterial pressure, antihypertensive medication, total cholesterol, high-density lipoprotein cholesterol, and heart rate. cfPWV range (m/s): Q1, <9.4; Q2, 9.4 to 11.0; Q3, 11.0 to 13.1, Q4 >13.1. hfPWV range (m/s): Q1, <9.9; Q2, 9.9 to 11.2; Q3, 11.2 to 12.9, Q4 >12.9. faPWV range (m/s): Q1, <9.9; Q2, 9.9 to 10.9; Q3, 10.9 to 12.0, Q4 >12.0. cfSG range: Q1, >1.18; Q2, 1.18 to 1.00; Q3, >0.99 to 0.82, Q4 <0.82. hfSG range: Q1, >1.13; Q2, 1.13 to 0.97; Q3, >0.97 to 0.83, Q4 <0.83.