Peripheral augmentation index defines the relationship between central and peripheral pulse pressure

Area of Science:

• Cardiovascular Physiology
• Hemodynamics
• Vascular Biology

Background:

• Peripheral systolic blood pressure exceeds central aortic systolic pressure due to amplification.
• The peripheral augmentation index, reflecting pressure wave reflection, is linked to late systolic pressure.

Purpose of the Study:

• To investigate the relationship between peripheral pulse waveform characteristics and central systolic pressure.
• To determine if the late systolic shoulder of the peripheral pulse approximates central systolic pressure.

Main Methods:

• Compared peripheral late systolic shoulder pressure with central systolic pressure estimates (transfer function and direct aortic root measurement) in 391 subjects.
• Measurements were taken at baseline, during atrial pacing, and nitroglycerin administration.

Main Results:

• Peripheral late systolic shoulder pressure closely approximated transfer function estimates of central pressure (R=0.96).
• Close agreement was maintained even with altered waveform morphology due to pacing and nitroglycerin (R=0.96).

Conclusions:

• The late systolic shoulder of the peripheral pulse is a reliable non-invasive estimate of central systolic pressure.
• Lowering augmentation index and peripheral vascular resistance may have multiplicative effects on reducing central blood pressure.