Distal Aortic Flow Reversal

During systole, flow in the arterial circulation will be in a forward direction. After ventricular ejection, a short period of flow reversal may occur as the aortic valve closes. This i typically seen in the ascending aorta and arch. After AV closure, flow in the aorta should be virtually zero. In the case of incomplete AV closure, blood will continue to flow back into the LV from the aortic root. As AI worsens, the degree of flow reversal will increase and become apparent more distal in the arterial tree. The demonstration of flow reversal throughout diastole (holodiastolic) in the distal descending aorta is a a very specific sign for severe AI. The sensitivity of holodiastolic flow is however reasonably low. Therefor the absence thereof can not exclude severe AI.

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In the descending aorta LAX view, follow the aorta downwards as far as possible. Apply light ante-flexion so that the aorta appears at a slight angle. This will optimise the angle for Doppler interrogation of the flow in the distal descending aorta. Select PW Doppler and position the sample volume distally in the aorta. Reduce the wall filter on your Doppler settings in order not to miss low velocity signals. The above spectral Doppler display shows systolic flow in the aorta below the baseline and holodiastolic flow reversal above baseline as seen in a patient with severe AI.

Note the 2D image on top of the image showing the PW sample volume in the descending aorta at the level of the diaphragm. Fluid in the left pleura can alo