[Pressure wave shape comparison between two non-invasive tonometric devices]

Background and aim: Pulse wave analysis is a pivotal instrument to estimate central hemodynamic parameters. Applanation tonometry on radial and/or carotid arteries is usually used to detect pressure waveforms. Available commercial devices have been validated against invasive catheterism, showing a good agreement of harmonics pattern. In a previous investigation, we observed differences on radial second systolic peak (rSPB2) between two commonly used devices: SphygmoCor (AtCor, Australia) and PulsePen (Diatecne, Italy). The aim of our study was to further quantify differences on radial and carotid signals from the two devices.

Methods: We measured radial and carotid pressure waveforms in 38 patients where systolic, diastolic blood pressure and heart rate presented minimal changes between measurements. Waveforms were digitally extracted for off-line analysis.

Results: Radial rSBP2, mean arterial pressure, form factor and augmentation index were different with SphygmoCor providing lower values. Carotid augmentation index and form factor were similar. However, carotid systolic pressure (cSBP) from PulsePen was higher that cSBP from SphygmoCor (2.7 ± 4.4 mmHg, P<0.001).

Conclusion: PulsePen and SphygmoCor sensors are not equivalent and provide different wave shapes. These differences on wave shape have important consequences on parameters computed from these waveforms with more discrepancy on radial derived parameters such as rSBP2 and mean arterial pressure than on carotid derived parameters. Further studies are required to compare invasive pressure parameters to indices derived from these two devices.