1
Arterial stiffness
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INTIMA
MEDIA
ADVENTITIA
MEDIA + ADVENTITA - responsible for arterial stiffness
Stiffness is ability to resist distension when a force is applied to it.
Compliance
C = ∆
V
∆
P
COMPLIANCE
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COMPLIANCE
Endothelial cells:
• endothelial dysfunction
• ↑ permeability
Intima:
• ↑ collagen
• ↓ elastin
• ↑ AGE`s, TGF-β, VSMC
Media:
• ↑ collagen
• ↓ elastin
• ↑ AGE`s, MMP, VSMC
Adventicia:
• ↑ collagen
• fibroblasts
Extrinsic influences
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MEASUREMENT OF THE
COMPLIANCE
Indirect ways
➢ Ultrasound
➢ Sphygmography (PWV a PWA)
➢ CAVI measurement
➢ Bioimpedance
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ULTRASOUND MEASUREMENT
5
Intima Media Thickness (IMT)
věk IMTR (mm) IMTL (mm)
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ULTRASOUND MEASUREMENT
66
β – index measurement
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CAVI MEASUREMENT
7
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CAVI MEASUREMENT
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PWV MEASUREMENT
A highly compliant aorta has a relatively low PWV (< 6 m/s)
PWV = distance (m) / transit time (s)
transit time = t2 – t1
PULSE WAVE
PULSE WAVE
PULSE WAVE
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P1 corresponds to the pressure at peak systolic flow and is usually identified by
the first shoulder of the pressure wave.
P2 corresponds to the peak of the reflected wave and is usually identified by
the peak of the pressure wave after the first shoulder.
PULSE WAVE ANALYSIS
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PULSE WAVE ANALYSIS
14
Higher values of AP and AIx indicate increased wave reflection from the periphery and/or early
return of the reflected wave as a result of increased pulse wave velocity (due to increased
arterial stiffness)
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Čas [s]
Tlak [mmHg]
SBP
DBP
TTI DTI
SEVR =
DTI
TTI
PULSE WAVE ANALYSIS
SEVR>140%
PBP
TTI - Tension Time Index (area under systolic part of the pulse curve)
DTI - Diastolic Time Index (area under diastolic part of the pulse curve)
SEVR - Buckberg Sub-Endocardial Viability Ratio – subendocardial blood supplying
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PULSE WAVE ANALYSIS