Regurgitant Flow Patterns

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Overview

Significant regurgitant lesions are characterized by a regurgitant jet , a regurgitant jet size, a PISA formation, a vena contracta, a "filled in" flow profile, a valvular abnormality, and a receiving chamber response. Depending upon the location of the valvular regurgitation, other abnormalities may be present.

Regurgitant Jet

The regurgitant jet on color flow doppler is a hallmark sign of regurgitation. The size of the jet depends upon the size of the regurgitant orifice and the pressure differential between the presenting (high pressure) and receiving (low pressure) chambers. If the pressure differential is low the size of the jet will be small, even with a large regurgitant orifice. If the regurgitant orifice is small, a large pressure differential will yield a small regurgitant jet.

A patient with a low ejection fraction cannot generate a large peak pressure, compared to a patient with a normal ejection fraction. In a patient with mitral regurgitation, the size of the mitral regurgitant jet will be smaller in the low ejection fraction left ventricle, compared to a normal ejection fraction left ventricle if both patients have the same regurgitant orifice size. Therefore, the pressure differential must be considered when interpreting the size of a regurgitant jet.

A large regurgitant orifice can also equalize the pressures between the presenting and receiving chambers, resulting in a low pressure differential. If a patient had "wide open" mitral regurgitation where the regurgitant orifice was so large the left atrium and the left ventricle where acting as one chamber, a pressure differential would not exist. Since a pressure differential does not exist, a regurgitant jet may not be present, even though the amount of regurgitation is severe.


Moderate MR with Normal LV Function Play Stop	Severe MR with Poor LV Function Play Stop	Wide Open MR Play Stop
		Wide Open TR (No TR Jet Present)

Jet Size

In most cases, the two above scenarios represent the extreme ends of mitral regurgitation and the regurgitant jets will be easily viewable on color flow doppler. To gauge the severity of regurgitant jets, measuring schemes have been developed for each type of regurgitation. Some confusion does exist in clinical situations because two competing measuring schemes are present. The number scheme, 1+, 2+, 3+, and sometimes 4+ is presented as a scheme to gauge the severity of a regurgitant jet. Each number correlates with the word scheme, trace, mild, moderate, and severe. Some measurement schemes will indicate a 2+ jet as a moderate jet, others will indicate a 3+ jet as a moderate or a severe jet. When discussing the jet severity with a surgeon, be sure that you are talking the same language.

Severity Scores


Trace Regurgitation Play Stop	Mild Regurgitation Play Stop	Moderate Regurgitation Play Stop	Severe Regurgitation Play Stop

PISA Formation

While a PISA formation can occur in stenotic valvular abnormalities, PISA formations can also occur in regurgitant valvular abnormalities. The velocity of the blood increases as it approaches the regurgitant orifice and forms isovelocity areas. When color flow doppler is applied to the regurgitant valve, the isovelocity areas are displayed with similar colors, resulting in arcs of similar color. Aliasing of the color arcs can occur. The area of the PISA formation can be used in various calculations to determine the effective regurgitant orifice, or, with CWD of the regurgitant jet, calculations of regurgitant volumes can be performed.

Vena Contracta

The vena contracta is the narrowest part of the high velocity jet that occurs with regurgitant lesions. Vena contracta width or area measurements are reproducible and measurable in central jets. The consistency of the vena contracta measurements has recently gained popularity and validity as an indicator of the severity of the regurgitation.

A large vena contracta indicates a large regurgitant orifice, and a small vena contracta indicates a small orifice. The jet size is dependent upon many factors (pressure gradient, receiving chamber size and compliance, etc) that may alter the interpreted jet size. The vena contracta tends to be more consistent.

Regurgitant Lesion

Flow Profile Quality

A continuous wave doppler of a regurgitant jet will indicate the severity of the regurgitant lesion. A continuous wave doppler will receive all of the velocities of the regurgitant jet along the CWD line of interrogation. If the regurgitant jet is mild, a high velocity jet may be present but, marked turbulence will not be present so the profile will appear not to be filled in with multiple velocities. A severe jet will have marked turbulence in the receiving chamber and will appear to be filled in. Moderate jets will appear in between the two extremes. While the jet quality cannot be quantified, it can be qualitatively diagnosed.


1X 2X 3X 4X	1X 2X 3X 4X	1X 2X 3X 4X
CWD Video (Mildly Filled)	CWD Video (Moderately Filled)	CWD Video (Completely Filled)

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