Aortic Pressure Tracing vs Femoral Arterial Pressure Tracing

Aortic pressure tracing vs femoral arterial pressure tracing

Aortic pressure tracing vs femoral arterial pressure tracing:

  1. Upstroke and downstroke are sharper in a peripheral arterial pressure tracing compared to the central aortic pressure tracing.
  2. Amplitude is higher in a peripheral tracing due to amplification of the pressure wave.
  3. The dicrotic notch in the peripheral arterial tracing will be lower compared to the incisura of the aortic pressure tracing. The differences are due to the higher resistance in the periphery and the presence of the reflected wave.
Aortic Pressure Tracing vs Femoral Arterial Pressure Tracing
Aortic Pressure Tracing vs Femoral Arterial Pressure Tracing

It is known that peripheral wave reflection, aorta-to-peripheral pulse pressure amplification and aortic stiffness, all predict cardiovascular risk [1]. Hence there is an importance in assessing the difference between aortic and peripheral arterial pulse wave forms.

Aortic pulse wave velocity and augmentation index has also been shown to predict morbidity and mortality due to cardiovascular disease in multiple populations in meta-analysis [1].

Augmentation index is measured from the central aortic wave form. It is a measure of systemic arterial stiffness. Aortic pressure tracing has two systolic peaks P1 and P2, of which P2 becomes more prominent after the age of 35 years. The difference between P2 and P1 expressed as a percentage of pulse pressure is the augmentation index [2].

Augmentation Index
Augmentation Index

Reflected wave responsible for aortic augmentation arises mostly in the lower extremities. Gradual stiffening of the arteries towards the periphery is also a cause for aorta to leg pulse amplification. Another important aspect of amplification is that it creates an inverse pressure gradient from periphery to central aorta [1].

References

  1. Junichiro Hashimoto, Sadayoshi Ito. Pulse Pressure Amplification, Arterial Stiffness, and Peripheral Wave Reflection Determine Pulsatile Flow Waveform of the Femoral Artery. Hypertension. 2010 Nov;56(5):926-33.
  2. I B Wilkinson, H MacCallum, L Flint, J R Cockcroft, D E Newby, D J Webb. The Influence of Heart Rate on Augmentation Index and Central Arterial Pressure in Humans. J Physiol. 2000 May 15;525 Pt 1(Pt 1):263-70.