Quantitative evaluation of aortic stenosis using continuous wave Doppler

Thirteen patients with suspected aortic stenosis were studied with left-heart catheterization and 2 D, Doppler echocardiography. Thickness and abnormal motion of aortic valve was detected by 2 D Echo in 12 cases. One case had thick aortic valve with normal motion. The causes of lesions included rheumatic heart disease in one patient, bicuspid aortic valve in one, and senile calcific aortic valves in eleven. The left ventricular and aortic pressure were recorded simultaneously with left-heart catheterization. Peak-to-peak, instant peak and mean pressure gradients were measured. The aortic velocity was obtained with Continuous Wave (CW) Doppler. Instant peak and mean pressure gradients were calculated from Bernoulli equation. Both catheterization and Doppler demonstrated significant pressure gradient between LV and aorta in twelve patients. The instant peak and mean pressure gradients calculated from CW Doppler were compared with catheterization data. Doppler pressure gradients correlated well with that measured at catheterization: Doppler instant peak pressure gradient compared with that by catheterization, r = 0.89, P less than 0.001, Doppler instant peak pressure gradient compared with peak-to-peak pressure gradient by catheterization, r = 0.79, P less than 0.001, Doppler mean pressure gradient compared with that by catheterization, r = 0.75, P = 0.002. This study demonstrates that CW Doppler provides a valuable method for assessment of the severity of aortic stenosis.     

Assessment of severity of aortic stenosis by continuous wave Doppler echocardiography

Fifty consecutive patients with aortic stenosis were evaluated by continuous wave Doppler echocardiography for assessment of the transaortic gradient. The Doppler derived gradients were compared with the gradients measured at cardiac catheterisation. Excellent correlation was found between the Doppler and catheterisation findings for the maximum instantaneous gradient (r = 0.92) and the mean systolic gradient (r = 0.84). The maximum, midsystolic and late systolic Doppler gradients also showed a good correlation with the peak to peak catheter gradient. The maximum Doppler velocity however, showed overestimation of the peak to peak gradient in the presence of mild aortic stenosis (predictive accuracy 86%). The midsystolic Doppler velocity showed the highest predictive accuracy (94%) for the detection of severe aortic stenosis. No case of severe aortic stenosis was missed by Doppler using either the maximum or midsystolic Doppler velocity. These findings indicate that continuous wave Doppler ultrasound provides a reliable estimate of the gradient in patients with aortic stenosis.     

Non-invasive study of aortic insufficiency by Doppler echocardiography

The possibilities of diagnosis and quantification of aortic regurgitation by pulsed Doppler analysis of blood flow in the aortic arch were examined in 60 patients aged between 9 and 67 years old. Aortic flow curves were recorded from the suprasternal area with the sample volume positioned at the junction of the horizontal part of the aortic arch and the descending aorta. Normal flow curves are characterised by an anterograde systolic wave with a brief proto-diastolic reflux. In aortic regurgitation holodiastolic reflux is observed. An index of regurgitation may be calculated from the ratio of the amplitude of end diastolic reflux measured on the R wave of th ECG and the maximal amplitude of anterograde systolic flow. This ratio eliminates the factor related to the incident angle between the ultrasound beam and the direction of blood flow. The values of this ratio were compared to the semi quantitative assessment of aortic regurgitation from ascending aortic angiography. The only false negatives were observed in patients with negligible regurgitation (grade I). One false positive result was obtained in a patient in whom it was difficult to obtain the recording and in whom the value of the ratio was very low (0,02). Global specificity was 91 p. 100 and sensitivity was 82 p. 100. The sensitivity for average or severe regurgitation was 100 p. 100. The correlation coefficient between the Doppler index or regurgitation and the semi quantitative angiographic estimation was 0,69. In patients with pure aortic regurgitation the correlation reached 0,85 (p less than 0,001). The differences between the different groups then became highly significant.     

Quantification of aortic regurgitation using continuous and pulsed wave Doppler echocardiography

In a prospective blind study, continuous and pulsed wave Doppler echocardiography were used to predict the severity of angiographically assessed aortic regurgitation in 36 patients. High quality continuous wave spectral recordings of the regurgitant jet were obtained in 32 patients but four patients with mild aortic regurgitation had dropout of high velocity signals precluding accurate assessment. The deceleration slope of the peak to end-diastolic velocity measured by continuous wave Doppler, and pulsed wave Doppler mapping of the regurgitant jet in the left ventricle were compared with angiographic severity. The deceleration slope was significantly steeper in patients with severe rather than mild or moderate aortic regurgitation (3.65 +/- 1.04 vs. 1.89 +/- 0.42 vs. 1.52 +/- 0.59 m sec-2). A decay slope of greater than 3 m sec-2 was observed only in patients with 3+ or 4+ aortic regurgitation and a decay slope less than 1.2 m sec-2 was seen only in mild 1+ aortic regurgitation but there was considerable overlap between groups, making it difficult in individual cases to assess severity on the basis of the continuous wave deceleration slope. The pulsed wave Doppler technique was more time consuming, added little to the continuous wave Doppler assessment and underestimated severe regurgitation in almost 50% of cases. Hence, there are significant problems using either Doppler technique in quantitatively assessing aortic regurgitation.     

Quantifying aortic valve insufficiency using color Doppler echocardiography

51 consecutive patients with the clinical signs of aortic valve incompetence (AI) were evaluated by color-coded Doppler flow mapping (CDF) before angiography (AG). Quantitation of the severity of AI was performed by measurement of length and width of the extension of regurgitant jet (grade I-IV). After AG results both -AG and CDF- were compared. In 36 patients the results of both methods concurred exactly by use length in CDF. With CDF, the regurgitation was overestimated in 7 cases by one grade and underestimated in 8 patients also by one grade. Width of regurgitant jet relative to size of outflow space is a useful parameter to distinguish between mild and severe A1 (limit 0.50). Conclusion: CDF is a suitable method for semiquantitative assessment of AI. In presence of unequivocal CDF signs and in consideration of clinical and other patients findings AG will be dispensable before aortic valve replacement.     

Evaluation of aortic stenosis by continuous wave Doppler ultrasound

Twenty-four patients with suspected aortic stenosis (Group I) were evaluated noninvasively by continuous wave Doppler ultrasound before undergoing cardiac catheterization. Twenty normal subjects served as the control group (Group II). Maximal velocity measurements in the ascending aorta ranged from 3.0 to 5.8 m/s (mean 4.34 +/- 0.65) in Group I versus 1.0 to 1.6 m/s (mean 1.28 +/- 0.16) in Group II (p less than 0.001). Using the Bernoulli equation, the peak pressure gradient across the aortic valve was calculated from the maximal velocity in the Group I patients. The results correlated well with the peak aortic valve gradient obtained at cardiac catheterization (r = 0.79). In 20 of these 24 patients, the peak Doppler gradient was within 25% of the gradient found at cardiac catheterization. In three patients, the Doppler study under-estimated the gradient by slightly more than 25% but still detected the presence of significant aortic stenosis. The Doppler technique failed to detect critical aortic stenosis in only one patient. Significant overestimation of the gradient by Doppler measurement did not occur in any patient. The technique was particularly helpful in older patients in whom other noninvasive tests often yield inconclusive results. An important but infrequent limitation of the technique is underestimation of the gradient that occurs when the angle of incidence between the ultrasound beam and aortic blood flow is too large. The findings indicate that continuous wave Doppler ultrasound provides a reliable estimate of the valvular gradient in most patients with aortic stenosis.     

Noninvasive evaluation of aortic regurgitation by continuous-wave Doppler echocardiography

Continuous-wave Doppler echocardiography was used to examine the aortic regurgitant flow velocity pattern in 32 patients with aortic regurgitation (AR) and 10 patients without AR. The aortic regurgitant flow velocity patterns, characterized by a rapid rise in flow velocity immediately after closure of the aortic valve, high peak flow velocity, and a gradual deceleration until the next aortic valve opening, were successfully obtained in 30 of the 32 patients with AR (sensitivity 94%, specificity 100%). The velocity decline was greater in patients with severe AR; thus, the slope of the velocity decline (deceleration) and the time to decline to half the peak velocity (half-time index) were measured from the flow velocity pattern. The deceleration became greater and the half-time index shortened in accordance with angiographic grading of AR (p less than .01). The deceleration and the half-time index also correlated well with the aortic regurgitant fraction (r = .79, p less than .01; r = -.89, p less than .01). Because the half-time index could be measured easily and independently of Doppler incident angle, it seemed a simple and accurate index of assessing the severity of AR. Thus continuous-wave Doppler echocardiography permitted the noninvasive evaluation of AR.     

Evaluation of aortic valve insufficiency using color Doppler echocardiography

Colour flow mapping Doppler echocardiography is a new, noninvasive method for studying the direction and velocity of blood flow within the cardiac chambers. In order to estimate the sensitivity and specificity of this method in the evaluation of aortic regurgitation, 44 patients were examined consecutively. In 24 patients, aortic valve incompetence was proven by angiography; in 20 patients aortography revealed no regurgitation. Quantification of the severity of aortic insufficiency was performed by grading the amount of colour of the regurgitant flow (grade I-IV) and comparing it with the angiographic data. In 43 out of 44 patients diagnostic images could be obtained with colour flow mapping Doppler echocardiography. With this method aortic insufficiency was detected in all cases (sensitivity 100%). The specificity was 97% (one false positive diagnosis). For quantification of the severity of regurgitation agreement with the angiographic findings was obtained in 18 out of 24 cases. In the remaining 6 patients the difference was one grade. Conclusion: Colour flow mapping Doppler echocardiography is an important advance in the noninvasive preoperative diagnostics of aortic incompetence.     

Quantitative assessment by Doppler echocardiography of pulmonary or aortic regurgitation

This study quantitates semilunar valve regurgitation by Doppler measurement of flows. The patients selected had single semilunar valve regurgitation; the other semilunar valve was normal. For the regurgitant valve, forward and reverse flows were measured in the great vessel distal to the abnormal valve, and reverse flow was subtracted from total forward flow to yield net flow. Net flow was compared with forward flow distal to the normal semilunar valve. If all values were computed accurately, net flow should equal forward flow distal to the normal semilunar valve. Twenty patients were studied and 18 had satisfactory recordings. Mean flow in the normal great vessel (3,511 ml/min) was not significantly different from mean net flow in the vessel with the abnormal valve (3,590 ml/min). The correlation coefficient for the paired flow measurements was +0.91 (685 ml [standard error of the estimate]). The slope of the relation was 0.88 and the intercept was 502 ml. Percent regurgitation varied from 29 to 73% and the percentage generally corresponded to clinical estimates. It is concluded that this method, which includes an internal control for each patient, is useful and reasonably accurate for clinical use in patients with pulmonary regurgitation, and appears clinically useful in some patients with aortic regurgitation.     

Diagnostic accuracy of continuous wave Doppler echocardiography in severe aortic stenosis in the elderly

Forty-four male patients (mean age 63.6 years) with aortic stenosis (AS) were evaluated by conventional hemodynamic methods and continuous wave (CW) Doppler echocardiography. The relationship between Doppler mean gradients and direct mean pressure gradients in all patients was significant, with an r value of 0.88. Sixteen of 17 patients with a mean Doppler gradient greater than or equal to 40 mmHg had severe AS (AVA less than or equal to 1.0 cm2). Twenty-seven patients had a Doppler gradient less than 40 mmHg, and 8 of these patients had severe AS (AVA less than or equal to 1.0 cm2). The sensitivity and specificity of a Doppler gradient greater than or equal to 40 mmHg in detecting severe AS were, therefore, 67% and 95%, respectively. Thirty-three percent (8/24) of patients with severe AS and low Doppler gradients (less than 40 mmHg) had evidence of poor left ventricular function, evidenced by a lower cardiac output, a higher heart rate and an abnormal PEP/LVET ratio compared to the other patients. Thus, the presence of a low stroke volume less than or equal to 60 ml/beat and PEP/LVET x HR greater than 26 is of value in identifying patients where the Doppler is likely to significantly underestimate the degree of aortic stenosis.     

Quantitative assessment of the hemodynamic consequences of aortic regurgitation by means of continuous wave Doppler recordings

The purpose of this study was to evaluate the ability of continuous wave Doppler ultrasound recordings to reflect the magnitude and hemodynamic effects of aortic regurgitation. Forty-five patients with angiographically proved aortic regurgitation had Doppler studies performed within 24 hours of cardiac catheterization. High quality spectral recordings of the regurgitant jet were obtained in 31 patients, whereas 14 patients exhibited dropout of high velocity signals precluding measurement of maximal velocities. The slope of the peak to end-diastolic velocity decrease measured by Doppler examination was compared with the decay in the aortic to left ventricular diastolic pressure gradient by catheterization and was found to correlate well (r = 0.86). The Doppler velocity decay slope was generally higher in patients with angiographically severe rather than mild or moderate aortic regurgitation, but considerable overlap was present among groups. However, a diastolic velocity decay slope of greater than 3 m/s2 was seen only in those patients with advanced (3 or 4+) aortic regurgitation. Left ventricular end-diastolic pressure was estimated from the Doppler recordings by subtracting the end-diastolic pressure gradient obtained by the modified Bernoulli equation from the cuff diastolic blood pressure. A correlation was observed (r = 0.84) between Doppler and catheterization left ventricular end-diastolic pressure in the 31 patients with high quality spectral data, although the SEE was substantial (5.5 mm Hg). These data demonstrate that continuous wave Doppler recordings of the regurgitant jet can be useful in assessing the angiographic severity and hemodynamics of aortic regurgitation.     

Variability in the transtricuspid gradient by continuous wave Doppler echocardiography.

In order to examine the day-to-day variability in the tricuspid regurgitant velocity jet and to determine the degree of physiological changes under exercise and volume loading, repeated echo cardiographic Doppler measurements in 1 single subject were performed.     

Exercise capacity in ischemic heart disease evaluated by continuous wave Doppler echocardiography

To evaluate exercise capacity in ischemic heart disease, we measured the peak aortic flow velocity by continuous wave Doppler (CWD) echo from the suprasternal notch at rest and during multiple load ergometer testing in the supine position. The study subjects consisted of 14 normal controls, 10 patients with effort angina and 21 patients with old myocardial infarction (OMI). In all the patients and in five normal subjects, thallium-201 emission CT (SPECT) was also performed immediately after exercise and four hours subsequently. Change in the peak aortic flow velocity during exercise was compared with the extent of perfusion defects and the presence or absence of redistribution images on SPECT. At rest, the peak aortic flow velocity was not different from that of the other three groups. During exercise, it increased progressively (crescendo type) as the exercise was increased in normal subjects. In patients with angina pectoris it increased at the initial stage of exercise, but was unchanged (crescendo-plateau type) or decreased (crescendo-decrescendo type) at the maximum exercise stage. Redistribution images on SPECT were seen in nine of 10 patients with angina pectoris. In patients with OMI, change in the peak aortic flow velocity was of the crescendo type in 14, crescendo-decrescendo in three and crescendo-plateau in one. In the remaining three it decreased from the beginning of exercise (decrescendo type). Redistribution images were seen in all patients with the crescendo-decrescendo, crescendo-plateau or decrescendo types. Furthermore, myocardial damage was much more extensive in the decrescendo type. We conclude that exercise continuous wave Doppler echocardiography is a useful means of evaluating exercise capacity in ischemic heart disease.     

Quantification of aortic regurgitation utilizing continuous wave Doppler ultrasound

Aortic regurgitation and mitral stenosis are hemodynamically similar, insofar as both result in passive ventricular filling across a narrow orifice driven by a declining pressure gradient. Because mitral stenosis is successfully characterized by Doppler ultrasound determination of the velocity half-time, or time constant, aortic regurgitation might be quantified in an analogous fashion. Eighty-six patients with diverse causes of aortic regurgitation underwent continuous wave Doppler examination before cardiac catheterization or urgent aortic valve replacement. The Doppler velocity half-time was defined as the time required for the diastolic aortic regurgitation velocity profile to decay by 29%, whereas catheterization pressure half-time was calculated as the time required for transvalvular pressure to decay by 50%. Doppler velocity and catheterization pressure half-times were linearly related (r = 0.91). Doppler velocity half-times were inversely related to regurgitant fraction (r = -0.88). Angiographic severity (1+ = mild to 4+ = severe) was also inversely related to pressure and velocity half-time; a Doppler half-time threshold of 400 ms separated mild (1+, 2+) from significant (3+, 4+) aortic regurgitation with high specificity (0.92) and predictive value (0.90). The Doppler velocity half-time was independent of pulse pressure, mean arterial pressure, ejection fraction and left ventricular end-diastolic pressure. Estimation of transvalvular aortic pressure half-time utilizing continuous wave Doppler ultrasound is a reliable and accurate method for the noninvasive evaluation of the severity of aortic regurgitation.     

组织多普勒腺苷负荷超声心动图定量评估心肌缺血的应用

目的 评价定量腺苷负荷超声心动图技术诊断冠心病的准确性.方法 40例患者行常规剂量(140μg·ks-1·min-1持续6 min静脉滴注)腺苷负荷超声心动图试验以评估心肌缺血.基于常规二维图像之上的组织多普勒成像采集基线状态和药物负荷状态下的心肌运动图像(美国GE VIVID7超声诊断仪),在ECHOPAC软件上进行后处理分析测量16节段心肌运动速度、应变、应变率.结果 以冠状动脉造影或CT冠状动脉成像为标准,共有缺血节段159个节段,非缺血节段465个.腺苷负荷峰值后,除缺血心肌的舒张早期应变(Se)无明显变化外,缺血心肌和非缺血心肌的收缩期速度(Sm)、舒张早期速度(Em)、舒张晚期速度(Am)和收缩期应变(Smax)以及收缩期应变率(SRs)、舒张早期应变率(SRe)、舒张晚期应变率(SRa),以及非缺血心肌的舒张早期应变(Se)均明显增加(P＜0.05).缺血心肌的基线Sm和Em均显著低于非缺血心肌[分别为(3.16±1.20)cm/s和(4.03±1.27)cm/s,P＜0.01;(3.75±1.67)cm/s和(4.66±1.70)cm/s,P＜0.05],峰值负荷下,两组间Sm和Em差异更加显著[分别为(3.98±1.63)cm/s和(5.07±1.52)cm/s;(4.51±2.32)cm/s和(6.52±2.56)cm/s;均P＜0.01];缺血心肌的收缩期应变(Smax)和舒张早期应变(Se)均明显低于非缺血心肌(分别为16.91%±3.35%和19.56%±5.47%,P＜0.01;9.53%±2.89%和13.06%±4.63%,P＜0.001).操作者工作特性(ROC)曲线所得曲线下面积以负荷峰值的Se最大(曲线下面积=0.740,敏感性为67%,特异性为83%).结论 组织多普勒负荷超声心动图参数可定量评估心肌缺血,是临床非创伤性诊断冠心病准确可靠的方法.     

Multiparameter evaluation of tricuspid insufficiency using two-dimensional echocardiography, Doppler and contrast echocardiography

The evaluation of the presence and severity of tricuspid insufficiency is still difficult even if many criteria of grading are available for different techniques. In this study the data obtained from Doppler mapping of the right atrium, from the analysis of the hepatic vein flow and from the contrast echocardiography of the inferior vena cava in 56 patients with mitral or mitral-aortic valvulopathy and with clinically suspected tricuspid insufficiency were submitted to the cluster analysis. This analysis was used to redistribute the study population according to the following parameters: diameter of the inferior vena cava, maximal systolic and diastolic flow of the hepatic veins, the length of regurgitant jet in right atrium and the duration of contrast in vena cava. The aim was to identify the variability range of each degree of severity. None of the analyzed parameters "per se" identifies the regurgitation severity because there is a large variability in the intermediate degrees. The cluster analysis shows a definite pattern of parameters for each cluster (1 = no significant regurgitation, 2 = mild, 3 = moderate, 4 = severe insufficiency).(ABSTRACT TRUNCATED AT 250 WORDS)     

Measurement of aortic regurgitation by Doppler echocardiography

In an attempt to develop a new approach to the non-invasive measurement of aortic regurgitation, transmitral volumetric flow (MF) and left ventricular total stroke volume (SV) were measured by Doppler and cross sectional echocardiography in 23 patients without aortic valve disease (group A) and in 26 patients with aortic regurgitation (group B). The transmitral volumetric flow was obtained by multiplying the corrected mitral orifice area by the diastolic velocity integral, and the left ventricular total stroke volume was derived by subtracting the left ventricular end systolic volume from the end diastolic volume. The aortic regurgitant fraction (RF) was calculated as: RF = 1 - MF/SV. In group A there was a close agreement between the transmitral volumetric flow and the left ventricular total stroke volume, and the difference between the two measurements did not differ significantly from zero. In group B the left ventricular total stroke volume was significantly larger than the transmitral volumetric flow, and there was good agreement between the regurgitant fractions determined by Doppler echocardiography and radionuclide ventriculography. Discrepancies between the two techniques were found in patients with combined aortic and mitral regurgitation or a low angiographic left ventricular ejection fraction (less than 35%). The effective cardiac output measured by Doppler echocardiography accorded well with that measured by the Fick method. Doppler echocardiography provides a new and promising approach to the non-invasive measurement of aortic regurgitation.