Pathophysiology
P-I-20. Investigation of vascular aging; pulse wave velocity
血管老化の検査；脈波伝播速度（PWV）
Vascular Aging
- Structural remodeling of arteries: increased diameter and wall thickness → decreased elasticity → may lead to endothelial dysfunction
- Partly age-related (cell biology), combined with cumulative exposure to classical risk factors (hypertension, diabetes, alcohol, smoking, obesity, physical inactivity)
Methods to investigate vascular aging
- Carotid intima-media thickening
- Aortic and carotid dilation
A. Testing Arterial Stiffness
- A persistent, progressive marker → a good tool to indicate past and present cardiovascular risk on the vessels
- Peripheral pulse pressure — heart-dependent, limited value; rises after age 50 (~50 mmHg); a +10 mmHg increase indicates CV risk
- Pulse wave analysis — mainly research; positive test = loss of pulse wave amplification and increased augmentation index
- Aortic pulse wave velocity (PWV) — the key stiffness measure
B. Testing Endothelial Dysfunction
- Flow-mediated dilatation measured in the brachial artery
Pulse Wave Velocity — Significance
- The arterial pulse wave is the pressure generated by the left ventricle during ejection, travelling through the arterial system
- It is reflected at several points (branching points, especially in the lower limb)
- The reflected wave superimposes on the forward pressure wave → an augmented (boosted) wave
- As it travels from aorta to periphery the wave becomes narrower and its amplitude rises (mean pressure unchanged) because:
- Peripheral arteries are more rigid, distorting the wave
- The pressure wave travels faster in stiffer peripheral arteries
- The inflection point (where reflected and ejected waves meet during systole) is the reference for measuring the augmentation index and augmentation pressure — important diagnostic indicators of how much the reflected wave raises pressure
- Higher PWV = stiffer aorta = greater cardiovascular risk
一問一答
▶What structural changes characterize vascular aging?
Increased arterial diameter and wall thickness with decreased elasticity, which may lead to endothelial dysfunction.
▶What two contributors drive vascular aging?
Intrinsic age-related cell biology plus cumulative exposure to classical risk factors (hypertension, diabetes, alcohol, smoking, obesity, inactivity).
▶What imaging/structural markers are used to investigate vascular aging?
Carotid intima-media thickening, and aortic/carotid dilation.
▶Why is arterial stiffness a useful cardiovascular risk marker?
It is a persistent, progressive marker reflecting both past and present cardiovascular damage to the vessels.
▶How does peripheral pulse pressure change with age, and what increase signals CV risk?
It rises after age 50 (~50 mmHg); a +10 mmHg increase indicates cardiovascular risk.
▶What does a positive pulse wave analysis test show?
Loss of pulse wave amplification and an increased augmentation index.
▶What is the key measure of arterial stiffness?
Aortic pulse wave velocity (PWV).
▶How is endothelial dysfunction tested?
By flow-mediated dilatation measured in the brachial artery.
▶What is the arterial pulse wave?
The pressure wave generated by the left ventricle during ejection, traveling through the arterial system.
▶How does the reflected wave affect the forward pressure wave?
It superimposes on the forward wave, producing an augmented (boosted) wave.
▶Where is the arterial pressure wave reflected?
At branching points (especially in the lower limb) and resistance vessels.
▶As the wave travels from aorta to periphery, how do its width and amplitude change?
It becomes narrower and its amplitude rises, while mean pressure stays unchanged.
▶Why does the pulse wave change shape toward the periphery?
Peripheral arteries are more rigid (distorting the wave) and the pressure wave travels faster in stiffer arteries.
▶What is the inflection point on the pressure wave?
The point where the reflected and ejected waves meet during systole — the reference for measuring augmentation index and augmentation pressure.
▶What do augmentation index and augmentation pressure indicate?
How much the reflected wave raises pressure — important diagnostic indicators of arterial stiffness.
▶Why is peripheral pulse pressure of limited value as a stiffness marker?
It is heart-dependent (influenced by stroke volume/ejection), so it less directly reflects arterial wall stiffness.
▶What does a higher PWV mean?
A stiffer aorta and greater cardiovascular risk.
▶How does endothelial dysfunction relate to vascular aging?
Loss of arterial elasticity from vascular aging can impair endothelial function, reducing flow-mediated vasodilation.
▶Why does the pressure wave travel faster in stiffer arteries?
Reduced wall compliance increases wave propagation speed (PWV rises with stiffness).
▶Why does mean arterial pressure stay roughly constant despite pulse wave amplification?
Amplification redistributes the waveform (raising systolic, narrowing the wave) without adding net energy, so the mean pressure is preserved.