Elevated augmentation index derived from peripheral arterial tonometry is associated with abnormal

Kevin S Heffernan1, Eshan A Patvardhan1, Michael Hession1

  • 1The Vascular Function Study Group, Division of Cardiology, Tufts Medical Center, Molecular Cardiology Research Institute, Boston, MA, USA.

Insights

The augmentation index (AIx) measured by peripheral arterial tonometry (PAT) reflects ventricular-vascular coupling. Abnormal coupling, whether from arterial or ventricular changes, is linked to higher PAT-AIx values.

Area of Science:

  • Cardiovascular Physiology
  • Biomedical Engineering
  • Vascular Diagnostics

Background:

  • Augmentation index (AIx) is typically derived from arterial pressure waveforms.
  • Peripheral arterial tonometry (PAT) allows AIx derivation from digital pulse volume waveforms.
  • Physiologic correlates of PAT-derived AIx and ventricular-vascular coupling are not well understood.

Purpose of the Study:

  • To investigate the relationship between AIx derived from PAT and measures of ventricular-vascular coupling.
  • To explore the clinical utility of PAT-AIx in assessing cardiovascular load.

Main Methods:

  • AIx was derived from pulse volume waves measured by PAT.
  • Effective arterial elastance index (EaI) and left ventricular (LV) end-systolic elastance index (E(LV)I) were calculated using echocardiography.
  • The ventricular-vascular coupling ratio was defined as EaI/E(LV)I.

Main Results:

  • Patients were stratified into low, optimal, and high ventricular-vascular coupling groups.
  • After adjusting for confounders, optimal coupling was associated with lower PAT-AIx (1 ± 4%).
  • Conversely, low (13 ± 4%) and high (19 ± 5%) coupling groups exhibited significantly higher PAT-AIx.

Conclusions:

  • Abnormal ventricular-vascular coupling, due to increased arterial or ventricular elastance, correlates with elevated PAT-AIx.
  • PAT-AIx may serve as a non-invasive indicator of ventricular-vascular coupling.
  • Further research is warranted to explore other vascular correlates of PAT-AIx.
Abstract

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