Determination of regurgitant fraction in isolated mitral or aortic regurgitation by pulsed Doppler two-dimensional echocardiography

Measurements of mitral and aortic valve flows were obtained with two-dimensional Doppler echocardiography in 25 patients with isolated mitral (n = 19) or aortic (n = 6) regurgitation and regurgitant fraction was calculated as the difference between the two flows divided by the flow through the regurgitant valve. Results were compared with measurements of regurgitant fraction determined by combined left ventricular angiography and thermodilution. Regurgitant fraction averaged 56 +/- 18% (range 19 to 79) by Doppler echocardiography and 48 +/- 17% (range 13 to 72) by angiography. A significant correlation was observed between the two methods (r = 0.91; SEE = 7%). In contrast, no significant correlation was found between regurgitant fraction measured by either method and the angiographic 1+ to 4+ qualitative classification of regurgitation. Doppler echocardiography appears to be an accurate method for the non-invasive quantification of severity of regurgitation in isolated left-sided valve lesions.     

Analysis of methodology for quantifying mitral regurgitation by Doppler echocardiography

It is generally agreed that Doppler echocardiography is highly sensitive and specific for the detection of mitral regurgitation. There is more confusion about its ability to quantitate the degree of mitral regurgitation. Studies of the intensity of the Doppler signals, as well as cross sectional Doppler studies apparently can provide a straightforward, but rough estimate of the degree of regurgitation in term of atrial extent of the disturbed flow. The methods are also sensitive to methodological errors as beam direction, movement of the heart, signal/noise relationship and the size of the left atrium. Another approach to the non-invasive measurement of mitral regurgitation includes the use of Doppler echocardiography for the determination of both aortic and mitral volumetric flow. In a study of patients with mitral regurgitation, we found a close correlation between the regurgitant fraction determined by Doppler echocardiography, and the regurgitant severity determined by left ventriculography. This technique can only be used in pure mitral regurgitation, while associated atrial fibrillation, mitral stenosis, and combined aortic and mitral regurgitation make correct measurements difficult.     

A new approach to noninvasive evaluation of aortic regurgitant fraction by two-dimensional Doppler echocardiography

The aortic regurgitant fraction was estimated noninvasively in 20 patients with aortic regurgitation from systolic aortic and pulmonary volume flow determined by duplex Doppler echocardiography. By assuming that an excess of the aortic volume flow (AF) compared with the pulmonary volume flow (PF) is due to aortic regurgitant flow, the aortic regurgitant fraction (RF) was calculated as follows: RF(%) = (AF - PF)/AF X 100. The aortic and pulmonary volume flows were determined as products of systolic integrals of ejection flow velocities and cross-sectional areas of the left and right ventricular outflow tracts, respectively. The Doppler estimate of the regurgitant fraction was compared by semiquantitative grading (1+ to 4+) by cineaortography and with the measurement of regurgitant fraction by catheter technique. The mean Doppler-determined aortic regurgitant fraction was 2.4% for normal subjects, 28.0% for the patients with 1+, 32.6% for the patients with 2+, 53.3% for the patients with 3+, and 62.4% for the patients with 4+. A fair correlation was found between Doppler estimates of regurgitant fraction and semiquantitative cineaortographic grades (r = .80, p less than .01). In the patients without associated mitral regurgitation, a close correlation was observed between Doppler and catheter estimates of regurgitant fraction (r = .96, p less than .01; y = 1.0x - 0.08). In the patients with associated mild mitral regurgitation, however, Doppler estimates of regurgitant fraction substantially underestimated those determined by the conventional catheter technique, which cannot separately quantitate the aortic regurgitant fraction in the presence of mitral regurgitation. These observations indicate that the proposed Doppler technique provides a useful method to evaluate the aortic regurgitant fraction specifically regardless of the presence of associated mitral lesions.     

Cross-sectional visualization of regurgitant jet by color flow mapping to evaluate aortic regurgitation

In the noninvasive evaluation of aortic regurgitation by Doppler echocardiography, flow mapping of the aortic regurgitant jet using the long-axis approach is of limited value in cases of combined mitral stenotic lesions. This is because the transmitral flow yields flow disturbances in the left ventricle, making it difficult to identify the extent of the aortic regurgitant jet. To overcome these limitations, the severity of aortic regurgitation was evaluated using the cross-sectional area of the aortic regurgitant jet at the level of the aortic valve as visualized by color flow imaging technique. The study population consisted of 16 patients with aortic regurgitation (10 with pure aortic regurgitation, five with superimposed mitral stenosis, and one with mitral valve replacement). Three normal subjects served as controls. The cross-section of the aortic regurgitant jet was visualized as a mosaic of yellow and blue in all patients with aortic regurgitation, but not in any of the controls. Planimetric measurements of the cross-sectional area of the regurgitant jet (J) and the aortic annulus area (Ao) were performed, and the Doppler parameter, J/Ao, was calculated. As a reference, the aortic regurgitant fraction (RF) was calculated from Doppler measurements of systolic aortic and pulmonary flows (AF and PF); RF (%) = (AF - RF)/AF x 100. The Doppler parameter, J/Ao, correlated well with the Doppler measurement of RF (r = 0.82, p less than 0.005), irrespective of the presence of associated mitral lesions. Thus, the cross-sectional area of the aortic regurgitant jet determined by color flow imaging technique would be a useful estimate of the severity of aortic regurgitation, even in the presence of associated mitral stenotic changes.     

Quantitative determination of aortic regurgitant volumes in dogs by ultrafast computed tomography

Current imaging modalities can provide only a qualitative or semiquantitative measure of the severity of aortic regurgitation. Ultrafast computed tomography (CT) has the capability of rapid imaging (17 frames/sec) coupled with high spatial resolution (1.5 mm2). Eight millimeter thick images can be acquired to interrogate simultaneously the right and left ventricles. End-diastolic and end-systolic tomograms can be reconstructed serially from apex to base by Simpson's rule to provide end-diastolic and end-systolic volumes from which the right and left ventricular stroke volumes can be derived. To determine whether the difference between left and right ventricular stroke volume measured with ultrafast CT could be used to estimate the volume of experimentally induced aortic regurgitation, we studied six dogs in which proximal aortic electromagnetic flow probes had been implanted. Varying degrees of aortic regurgitation were induced by manipulation of a basket catheter through the aortic valve. During suspended respiration in the control state in the absence of aortic regurgitation, right and left ventricular stroke volumes measured with ultrafast CT were nearly identical (mean difference 1.0 +/- 1.2 ml [mean +/- SE]). In the presence of varying degrees of aortic regurgitation, regurgitant volume derived by ultrafast CT as the difference between right and left ventricular stroke volumes correlated closely to the regurgitant volume measured by the electromagnetic flow probe (r = .99, slope = .92, y intercept = 0.98 ml, SEE = 1.02 ml, n = 16). Regurgitant fraction also correlated closely to the regurgitant fraction measured by the electromagnetic flow probe (r = .94, slope = .98, y intercept = 0.66%, SEE = 4.73%, n = 16).(ABSTRACT TRUNCATED AT 250 WORDS)     

Measurement of mitral regurgitation by Doppler echocardiography.

In an attempt to develop a new approach to the non-invasive measurement of mitral regurgitation, Doppler echocardiography and left ventriculography were performed in 20 patients without valvar heart disease (group A) and in 30 patients with pure mitral regurgitation (group B). Volumetric flows through the aortic and the mitral orifices were determined by Doppler echocardiography. Aortic flow (AF) was calculated as the product of the aortic orifice area and the systolic velocity integral. The mitral flow (MF) was calculated as the product of the corrected mitral orifice area and the diastolic velocity integral. The mitral regurgitant fraction (RF) was calculated as RF = 1 - AF/MF. In group A aortic and mitral flow were very similar and the difference between the two did not differ significantly from zero. In group B the mitral flow was significantly larger than the aortic flow. There was a good correlation (r = 0.82) between the regurgitant fraction determined by Doppler echocardiography and the regurgitant grades determined by left ventriculography. The regurgitant fraction increased significantly with each grade of severity. These results show that Doppler echocardiography can be used to give a reliable measure of both aortic and mitral flow. This technique is a new and promising approach to the non-invasive measurement of mitral regurgitation.     

Assessment of severity of aortic regurgitation by M-mode colour Doppler flow imaging

To assess the value of measuring the aortic regurgitant jet diameter at its origin by M-mode colour Doppler imaging, 82 patients with aortic regurgitation underwent, within 72 h of each other, colour Doppler examination and angiography. After excluding one patient without colour Doppler aortic regurgitation and five with a highly eccentric regurgitant jet, we found a close relationship between the jet diameter at its origin measured by M-mode colour Doppler and the angiographic grade of aortic regurgitation (r = 0.88). A jet diameter greater than or equal to 12 mm identified severe aortic regurgitation (grade III or IV) with a sensitivity of 86.4% and a specificity of 94.4%. In 38 patients, the jet diameter correlated well with the regurgitant fraction measured by a combined haemodynamic-angiographic method (r = 0.88). A jet diameter greater than or equal to 12 mm identified a regurgitant fraction greater than or equal to 40% with a sensitivity of 88.2% and a specificity of 95.2%. This study indicates that the size of the regurgitant jet diameter at its origin measured by M-mode colour Doppler provides a simple and useful measure of the severity of aortic regurgitation. It may allow differentiation between mild or moderate and severe aortic regurgitation and evaluation of regurgitant fraction.     

Measurement of mitral regurgitation by Doppler echocardiography

In an attempt to develop a new approach to the non-invasive measurement of mitral regurgitation, Doppler echocardiography and left ventriculography were performed in 20 patients without valvar heart disease (group A) and in 30 patients with pure mitral regurgitation (group B). Volumetric flows through the aortic and the mitral orifices were determined by Doppler echocardiography. Aortic flow (AF) was calculated as the product of the aortic orifice area and the systolic velocity integral. The mitral flow (MF) was calculated as the product of the corrected mitral orifice area and the diastolic velocity integral. The mitral regurgitant fraction (RF) was calculated as RF = 1 - AF/MF. In group A aortic and mitral flow were very similar and the difference between the two did not differ significantly from zero. In group B the mitral flow was significantly larger than the aortic flow. There was a good correlation (r = 0.82) between the regurgitant fraction determined by Doppler echocardiography and the regurgitant grades determined by left ventriculography. The regurgitant fraction increased significantly with each grade of severity. These results show that Doppler echocardiography can be used to give a reliable measure of both aortic and mitral flow. This technique is a new and promising approach to the non-invasive measurement of mitral regurgitation.     

Quantitative assessment of aortic regurgitation by combined two-dimensional, continuous-wave and colour flow Doppler measurements.

The width of the regurgitant jet at the aortic valve plane, i.e. the core flow diameter, the ratio of the jet width to the left ventricular outflow diameter, the regurgitant volume and regurgitant fraction were determined using two-dimensional, continuous wave and colour flow Doppler echocardiography. The relationship between the non-invasive measurements and semiquantitative angiographic grading of the regurgitant flow (1 + to 4+) was examined in a primary group of 20 patients with chronic aortic regurgitation. Cut-off points for the non-invasive measurements were selected so as to separate patients with mild or moderate regurgitation (1+ or 2+) from patients with moderately severe or severe regurgitation (3+ or 4+). These cut-off points were prospectively applied in a new group of 35 patients with aortic regurgitation to predict the angiographic grading. Jet width correctly predicted the angiographic grading in 86% of cases, the ratio of the jet width to the outflow diameter in 83% of cases, the regurgitant volume in 86% of cases and the regurgitant fraction in 91% of cases. We conclude that the severity of aortic regurgitation as determined by angiographic grading can be estimated with reasonable accuracy by non-invasive techniques based on colour flow imaging.     

Quantification of aortic regurgitation with amplitude-weighted mean flow velocity from continuous wave Doppler spectra

Aortic regurgitant fraction (RFao) was quantified by estimating the ratio of the forward blood flow through the aortic (Qao) and pulmonary (Qp) valve: RFao = 100(Qao - Qp)/Qao. Aortic and pulmonary flow were measured by the systolic time integrals of the amplitude-weighted mean velocity from continuous wave Doppler spectra recorded over the aortic and pulmonary valves. Thus, measurements are independent of the left and right ventricular outflow tract area. In 20 normal subjects, aortic regurgitant fraction ranged between -2.9% and +12.0% (mean +4.3%), the physiologic value being +2%. In 20 patients with pure aortic regurgitation, aortic regurgitant fraction obtained by Doppler spectra (y) was compared with that calculated from biplane left ventriculography and cardiac output determined with the Fick method (x). The correlation was r = 0.94, (SEE = 5.4%, which is 10.6% of the angiography-Fick mean value). The regression line was y = 0.87x + 6.6 (mean y = 51.2%, mean x = 51.1%). It is concluded that determination of aortic regurgitant fraction in pure aortic regurgitation by using the amplitude-weighted mean velocity from continuous wave Doppler spectra is accurate and allows easy noninvasive evaluation of the regurgitant fraction in routine clinical applications.     

Doppler echocardiography measurement of the regurgitation fraction in patients with aortic valve insufficiency

The purpose of this study was to assess the clinical utility of pulsed Doppler echocardiography in the determination of regurgitant fraction in patients with aortic regurgitation. Therefore, in 33 unselected consecutive patients with aortic regurgitation, and in 16 patients without heart disease Doppler echocardiography was performed to measure blood flow at the aortic and pulmonary valve. The regurgitant blood flow (RBV) was calculated as the difference of the stroke volumes measured at the aortic and pulmonary valve. The regurgitant fraction (RF) was computed as RBV/aortic flow. At cardiac catheterization RBV and RF were calculated from the left ventricular angiographic stroke volume and the stroke volume measured by thermodilution technique. Four patients were excluded because of technically poor left-ventricular angiograms. In eight patients with aortic regurgitation Doppler measurement of RBV and RF was impossible. The correlations between the invasive and the Doppler data were significant in 21 patients with aortic regurgitation (RBV: r = 0.87, SEE = 16.1 ml; RF: r = 0.90, SEE = 8.1%). However, the RF (41.6 +/- 17.6%) was overestimated by Doppler echocardiography (46.0 +/- 17.9%; p les than 0.021). In the control group RBV ranged between -8.1 ml and 10.5 ml and RF between -13.3% and 7.4%. Thus, pulsed Doppler echocardiography is clinically useful in determination of the regurgitant fraction in about 70% of patients with pure aortic regurgitation. The Doppler method, however, is limited in the diagnosis and quantification of mild aortic regurgitation.     

A simplified method for determining regurgitant fraction by Doppler echocardiography in patients with aortic regurtitation

Objectives. This study attempted to develop and validate a simple method for calculating aortic regurgitant fraction by use of pulsed wave Doppler echocardiography.Background. Although several investigators have been able to determine aortic regurgitant fraction by Doppler echocardiography, the methods used require accurate determination of the cross-sectional areas of intracardiac sites at which the volumetric flow is calculated.Methods. Our concept was based on a constant relation that exists between the cross-sectional area of the left ventricular outflow tract and the mitral valve annulus in normal subjects. To verify this, we used Doppler echocardiography to measure the flow velocity integral of the left ventricular outflow tract and the mitral annulus in the apical view in 50 normal subjects (32 men, 18 women, mean age 34 years).Results. Close correlation (r = 0.95) was observed between the flow velocity integral (FVI) of the outflow tract (OT) and that of the mitral annulus (MA): FVI_MA/FVI_OT= 0.77. Because mitral flow equals aortic flow in normal subjects, the ratio of the cross-sectional area of the mitral annulus to that of the outflow tract was 1/0.77. In patients with aortic regurgitation, the regurgitant fraction (RF) = (Aortic flow − Mitral flow)/Aortic flow = 1 − Mitral flow/Aortic flow. Substituting 0.77 for the area component of flow, RF = 1 − (1/0.77) · (FVI_MA/FVI_OT). To evaluate the accuracy of this method, we compared the regurgitant fraction derived by Doppler echocardiography with that from catheterization findings in 20 patients with aortic regurgitation (an isolated lesion was found in 14). The regurgitant fraction by catheterization was the difference between total (angiographic) and forward (thermodilution) stroke volumes as a percent of total flow. Good correlation was observed between catheterization and Doppler regurgitant fraction (r = 0.88, SEE 9%, p < 0.01).Conclusions. Thus, regurgitant fraction can be estimated from Doppler echocardiography in patients with aortic regurgitation by a method that requires only measurements of the flow velocity integral from the mitral annulus and left ventricular outflow tract.     

Doppler assessment of aortic regurgitation. Correlation with hemodynamics and angiography

The Doppler method by permitting assessment of transvalvular blood flow velocity has provided a direct means to interrogate aortic regurgitant flow. Pulsed Doppler permits detection of disturbed diastolic flow by sampling proximal to the aortic valve in the outflow tract and is highly sensitive for diagnosis of aortic regurgitation (AR). For semi-quantitative assessment of the severity, left ventricular (LV) mapping can be performed and a ratio of the area of retrograde diastolic to antegrade systolic flow in the descending aorta can be used. According to the continuity principle, it should be possible to estimate regurgitant fraction by examination of forward flows from two different sites, one representative of forward output and one of total left ventricular output, but this method has not yet been sufficiently validated. Continuous wave (CW) Doppler is nearly as sensitive for detection of aortic regurgitation as pulsed wave (PW) Doppler. Signal strength of regurgitant jet provides an indirect clue to its severity: generally a strong signal indicates moderate to severe degree, a weak signal is associated with mild degrees of regurgitation. The spectral outline of regurgitant jet velocity is determined by instantaneous pressure difference between aortic root and the left ventricle during diastole and an indirect clue to severity of aortic regurgitation is provided by the slope of the curve. A steeper slope or shorter velocity half-time is associated with more severe degrees of regurgitation and vice versa. However, there is considerable scatter in this correlation for any given grade of severity of aortic regurgitation, providing a limited predictive value.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effective regurgitant orifice area: A noninvasive Doppler development of an old hemodynamic concept

Objectives. The purpose of this study was to determine the feasibility, relation to other methods and significance of the effective regurgitant orifice area measurement.Background. Assessment of the severity of valvular regurgitation (effective regurgitant orifice area) has not been implemented in clinical practice but can be made by Doppler echocardiography.Methods. Effective regurgitant orifice area was calculated by Doppler echocardiography as the ratio of regurgitant volume/ regurgitant jet time-velocity integral and compared with color flow Doppler mapping, angiography, surgical classification, regurgitant fraction and variables of volume overload.Results. In 210 consecutive patients examined prospectively, feasibility improved from the early to the late experience (65% to 95%). Effective regurgitant orifice area was 28 ± 23 mm²(mean ± SD) for aortic regurgitation (32 patients), 22 ± 13 mm²for ischemic/functional mitral regurgitation (50 patients) and 41 ± 32 mm²for organic mitral regurgitation (82 patients). Significant correlations were found between effective regurgitant orifice and mitral jet area by color flow Doppler mapping (r = 0.68 and r = 0.63, p < 0.0001, respectively) and angiographic grade (r = 0.77, p = 0.0004). Effective regurgitant orifice area in surgically determined moderate and severe lesions was markedly different in mitral regurgitation (35 ± 12 and 75 ± 33 mm², respectively, p = 0.009) and in aortic regurgitation (21 ± 8 and 38 ± 5 mm², respectively, p = 0.08). Strong correlations were found between effective regurgitant orifice area and variables reflecting volume overload. A logarithmic regression was found between effective regurgitant orifice area and regurgitant fraction, underlining the complementarity of these indexes.Conclusions. Calculation of effective regurgitant orifice area is a noninvasive Doppler development of an old hemodynamic concept, allowing assessment of the lesion severity of valvular regurgitation. Feasibility is excellent with experience. Effective regurgitant orifice area is an important and clinically significant index of regurgitation severity. It brings additive information to other quantitative indexes and its measurement should be implemented in the comprehensive assessment of valvular regurgitation.     

Noninvasive quantification of mitral regurgitation in dilated cardiomyopathy: correlation of two Doppler echocardiographic methods

The presence and severity of functional mitral regurgitation were quantified by Doppler echocardiography in 17 patients with dilated cardiomyopathy and no evidence of primary valvular disease. Mitral regurgitant fraction was greater than 20% in 11 of the 17 patients, and exceeded 40% in four patients. Total stroke volume, calculated from the difference between end-diastolic and end-systolic volumes obtained by two-dimensional echocardiography, correlated well with mitral valve inflow determined by Doppler echocardiography (r = 0.90, p less than 0.001). Similarly, mitral regurgitant volume, calculated as the difference between echocardiographic total stroke volume and forward aortic volume obtained by Doppler echocardiography, correlated well with regurgitant volume calculated as the difference between mitral valve inflow and forward aortic flow, both determined by Doppler echocardiography (r = 0.90, p less than 0.001). Accordingly, functional mitral regurgitation can be conveniently demonstrated in patients with dilated cardiomyopathy by two different Doppler echocardiography methods, whose results are closely correlated. Mitral regurgitant fraction is greater than 20% in two thirds of the patients with a dilated cardiomyopathy.     

Non-invasive measurement of the regurgitant fraction by pulsed Doppler echocardiography in isolated pure mitral regurgitation.

OBJECTIVE--To assess the usefulness of pulsed Doppler echocardiography as a method of measuring the regurgitant fraction in patients with mitral regurgitation. PATIENTS AND METHODS--Twenty controls and 27 patients with isolated mitral regurgitation underwent Doppler studies. In the patients the study was performed within 48 hours of cardiac catheterisation. Aortic outflow was measured in the centre of the aortic annulus, and mitral inflow was derived from the flow velocity at the tip of the leaflets and the area of the elliptical mitral opening. The regurgitant fraction was calculated as the difference between the two flows divided by the mtiral inflow. RESULTS--In the 20 controls the two flows were almost identical (mitral inflow, 4.44 (SD 0.88) l/min; aortic outflow, 4.58 (SD 0.84) l/min), with a mean regurgitant fraction of 4.2 (SD 8.4)%. In patients with mitral regurgitation, the mitral inflow was significantly higher than the aortic outflow (8.8 (3.6) v 4.3 (1.1) l/min). In most patients the Doppler-derived regurgitant fraction (45.8 (19.2)%) accorded closely with the regurgitant fraction (41.3 (SD 17.8)%) determined by the haemodynamic technique. CONCLUSION--Pulsed Doppler echocardiography, with an instantaneous velocity-valve area method for calculating mitral inflow, reliably measured the severity of regurgitation in patients with mitral regurgitation.     

Strategy for optimal aortic regurgitation quantification by Doppler echocardiography: agreement among different methods

BACKGROUND: Although different Doppler methods have been validated for aortic regurgitation quantification, the benefit of combining information from different methods has not been defined. METHODS: Our study included 2 phases. In the initial phase (60 patients), Doppler parameters (jet width, short-axis jet area, apical jet area, regurgitant fraction from pulmonary and mitral flow, and deceleration slope) were correlated with angiography; range values for each severity grade were defined and intraobserver and interobserver and intermachine variability were studied. In the validation phase (158 patients), defined value ranges were prospectively tested and a strategy based on considering as the definitive severity grade that in which the two best methods agreed was tested. RESULTS: Jet width had the best correlation with angiography (r = 0.91), and its ratio with the left ventricular outflow diameter did not improve the correlation (r = 0.85) and decreased reproducibility. Apical jet area and regurgitant fraction from pulmonary flow permitted acceptable quantification (r = 0.87 and 0.86, respectively) but with worse reproducibility. The other methods were not assessable in 20% to 30% of studies. Concordance with angiography decreased in jet width when the jet was eccentric (90% vs 77%, P <.01), in apical jet area when mitral valve disease was present (84% vs 65%, P <.02), and in short-axis jet area and regurgitant fraction from pulmonary flow with concomitant aortic stenosis (77% vs 44%, P <.002 and 77% vs 53%, P <.02, respectively). Agreement with angiography was very high (94 [95%] of 99) when severity grade coincided in both jet width and apical jet area. In 59 cases without concordance, regurgitant fraction from pulmonary flow was used as a third method. Overall, this strategy permitted concordance with angiography in 146 patients (92%). CONCLUSIONS: Jet width is the best predictor in aortic regurgitation quantification by Doppler echocardiography. However, better results were obtained when a strategy based on concordance between jet width and another Doppler method was established, particularly when the jet was eccentric.     

Prevalence of regurgitant murmurs in patients with valvular regurgitation detected by Doppler echocardiography

STUDY OBJECTIVE: To determine the relation between heart valve regurgitation detected by Doppler echocardiography and audible regurgitant murmurs. DESIGN: Consecutive sample. SETTING: Adult echocardiography laboratory in a tertiary care university hospital. PATIENTS: Sequential sample of 408 patients presenting for clinical echocardiographic studies who had technically satisfactory studies and were available for auscultation. MEASUREMENT AND MAIN RESULTS: Valvular regurgitation occurred in 43% of patients at the mitral valve, 39% of patients at the tricuspid valve, 33% of patients at the aortic valve, and 15% of patients at the pulmonic valve. Corresponding regurgitant murmurs were frequently absent. A murmur corresponding to Doppler-detected regurgitation was detected in 56% of patients with mitral regurgitation, 61% of patients with aortic regurgitation, 28% of patients with tricuspid regurgitation, and 15% of patients with pulmonic regurgitation. There was a highly significant positive correlation of audibility with severity of valve regurgitation for the aortic, tricuspid, and mitral valves. Audibility ranged from 10% to 40% for mild regurgitation to 86% to 100% for severe regurgitation. Murmur audibility was not related to the type of valvular disease present. CONCLUSIONS: Doppler echocardiography is a sensitive method for detecting valve regurgitation. Corresponding regurgitant murmurs are frequently not present. The audibility of regurgitant murmur is highly dependent on the severity of valve regurgitant and has little relation to the type of valve disease present.     

Aortic regurgitation: quantitative methods by echocardiography

Quantification of aortic regurgitation (AR) is a common and difficult clinical problem. The severity of regurgitation has traditionally been estimated with the use of contrast aortography, which is impractical as a screening tool or for serial examinations. In the past two decades, Doppler echocardiography has emerged as an important tool in the quantification of AR. Pulsed Doppler mapping of the depth of the regurgitant jet into the left ventricle was one of the initial echocardiographic methods used for this purpose. The slope and pressure (or velocity) half-time of continuous-wave Doppler profiles of regurgitant jets are also useful. These Doppler techniques may be used to determine the regurgitant volume or regurgitant fraction in patients with AR. The use of color Doppler to measure the height (or cross-sectional area) of the regurgitant jet relative to the height (cross-sectional area) of the left ventricular outflow tract is both sensitive and specific in the quantification of AR. More recently, the continuity principle has been used to determine the effective aortic regurgitant orifice area, which increases as AR becomes more severe. Although this is a promising tool, calculation of this value is not yet common practice in most echocardiography laboratories. Although no single echocardiographic technique is without limitations, all have some validity, and it is reasonable to use a combination of them to obtain a composite estimate of the severity of AR.     

Non-invasive measurement of the regurgitant fraction by pulsed Doppler echocardiography in isolated pure mitral regurgitation.

OBJECTIVE--To assess the usefulness of pulsed Doppler echocardiography as a method of measuring the regurgitant fraction in patients with mitral regurgitation. PATIENTS AND METHODS--Twenty controls and 27 patients with isolated mitral regurgitation underwent Doppler studies. In the patients the study was performed within 48 hours of cardiac catheterisation. Aortic outflow was measured in the centre of the aortic annulus, and mitral inflow was derived from the flow velocity at the tip of the leaflets and the area of the elliptical mitral opening. The regurgitant fraction was calculated as the difference between the two flows divided by the mtiral inflow. RESULTS--In the 20 controls the two flows were almost identical (mitral inflow, 4.44 (SD 0.88) l/min; aortic outflow, 4.58 (SD 0.84) l/min), with a mean regurgitant fraction of 4.2 (SD 8.4)%. In patients with mitral regurgitation, the mitral inflow was significantly higher than the aortic outflow (8.8 (3.6) v 4.3 (1.1) l/min). In most patients the Doppler-derived regurgitant fraction (45.8 (19.2)%) accorded closely with the regurgitant fraction (41.3 (SD 17.8)%) determined by the haemodynamic technique. CONCLUSION--Pulsed Doppler echocardiography, with an instantaneous velocity-valve area method for calculating mitral inflow, reliably measured the severity of regurgitation in patients with mitral regurgitation.