Background: new commercially available radiofrequency (RF) based ultrasound (US) allows accurate depiction of common carotid (CCA) distension waveforms, whereas carotid applanation tonometry represents a validated technique for pressure waveform description. From both distension and pressure waveforms local carotid pressure and some hemodynamic indices, such as Left Ventricular Ejection Time (LVET), are obtained. Aim of this study was to validate estimates of local CCA pressure and LVET by ultrasound distension waveforms against applanation tonometry.

Methods: in 112 subjects (66 males; mean age 56.2±9.9; 16 non diabetic non hypertensive, NL; 34 hypertensives, HT; 62 diabetics, DM), right CCA distension waveforms were obtained by RF-based wall tracking of the near and far wall (MyLab70, Esaote). Afterwards, CCA pressure waveforms were recorded by applanation tonometry (Pulsepen, Diatecne). Local systolic, diastolic and pulse pressure were derived calibrating both waveforms for brachial pressure (Omron) as previously described (Van Bortel LM et al, J Hypertens 2001). LVET was also evaluated with both systems.

Results: brachial SBP and PP were 137.0±17.1 and 57.4±13.9 mmHg, significantly higher (p<0.001) than those recorded by tonometry or US. Brachial DBP was 79.6 ± 8.9 mmHg. US-derived SBP, DBP and PP were slightly but significantly higher than tonometric values, while LVET was lower (see Table).

However, corresponding measures obtained with the two techniques were well correlated (r values from 0.754 and 0.896, p< 0.001). In Bland-Altman analysis, the outliers were between 4 and 6 for each parameter.

Conclusions: RF-US allows accurate estimate of central BP and LVET.