Augmentation Pressure or Augmentation Index Unusually High or Low
Unexpected AP or AIx values are most often driven by test conditions, cuff setup, or waveform quality rather than a device malfunction.
Step 1: Understand What AP and AIx Represent
- Augmentation Pressure (AP): The additional pressure contributed by wave reflection. Elevated AP reflects arterial stiffness and extra cardiac workload.
- Augmentation Index (AIx): The proportion of total central pressure caused by wave reflection (how much pressure is returning toward the heart). Report interpretation and clinical decisions must be made by a qualified physician.
Step 2: Standardize Test Conditions
- Standardize patient preparation: rest, no talking or movement, same time of day.
Step 3: Verify Cuff Size and Placement
- Use the same cuff verification steps described in the Low Operator Index section above.
Step 4: Check Waveform Quality
- If the capture is noisy or unstable, treat the issue as a waveform quality problem: reposition the cuff, allow additional rest, and repeat.
- If quality issues persist, try the other arm and document the change.
Step 5: Consider Patient Factors
- Be aware of factors that may degrade signal quality (arrhythmias, tremors, inability to rest quietly), and document them for clinical interpretation.