Is the blood velocity beat-to-beat variation in the descending aorta similar to the arterial pulse pressure variation?

The beat-to-beat analysis of the arterial pulse pressure (PP) [1] and of the maximal aortic velocity measured by the transesophageal echocardiographic Doppler technique (TEE) [2] have been demonstrated as good predictors of volume responsiveness in patients with circulatory failure. However, the PP analysis requires an invasive procedure for arterial catheter placement and TEE does not allow long-term continuous analysis. Therefore, we have tested the hypothesis that the beat-to-beat variation of the peak of velocity of blood in the descending aorta (PV Ao), measured by a transesophageal echo-doppler device (a less invasive monitoring technique using a small probe) was of the same degree as the beat-to-beat PP variation measured by an arterial catheter.