Aortic stenosis: echocardiographic cusp separation and surgical description of aortic valve in 22 patients

Maximal Aortic Valve Cusp Separation and Severity of Aortic Stenosis

INTRODUCTION

An integrated approach that incorporates two dimensional, M mode and Doppler echocardiographic evaluation has become the standard means for accurate quantification of severity of valvular aortic stenosis. Maximal separation of the aortic valve cusps during systole has been shown to correlate well with the severity of aortic stenosis measured by other echocardiographic parameters.

AIM

To study the correlation between Maximal Aortic valve Cusp Separation (MACS) and severity of aortic valve stenosis and to find cut-off values of MACS for detecting severe and mild aortic stenosis.

MATERIALS AND METHODS

In the present prospective observational study, we have compared the accuracy of MACS distance and the aortic valve area calculated by continuity equation in 59 patients with varying degrees of aortic valve stenosis. Aortic leaflet separation in M mode was identified as the distance between the inner edges of the tips of these structures at mid systole in the parasternal long axis view. Cuspal separation was also measured in 2D echocardiography from the parasternal long axis view and the average of the two values was taken as the MACS. Patients were grouped into mild, moderate and severe aortic stenosis based on the aortic valve area calculated by continuity equation. The resultant data regarding maximal leaflet separation on cross-sectional echocardiogram was then subjected to linear regression analysis in regard to correlation with the peak transvalvular aortic gradient as well as the calculated aortic valve area. A cut-off value for each group was derived using ROC curve.

RESULTS

There was a strong correlation between MACS and aortic valve area measured by continuity equation and the peak and mean transvalvular aortic gradients. Mean MACS was 6.89 mm in severe aortic stenosis, 9.97 mm in moderate aortic stenosis and 12.36 mm in mild aortic stenosis. MACS below 8.25 mm reliably predicted severe aortic stenosis, with high sensitivity, specificity and positive predictive value. MACS above 11.25 mm practically ruled out significant aortic stenosis.

CONCLUSION

Measurement of MACS is a simple echocardio-graphic method to assess the severity of valvular aortic stenosis, with high sensitivity and specificity. MACS can be extremely useful in two clinical situations as a simple screening tool for assessment of stenosis severity and also helps in decision making non invasively when there is discordance between the other echocardiographic parameters of severity of aortic stenosis.

Core review: physician-performed ultrasound: the time has come for routine use in acute care medicine

The use of ultrasound in the acute care specialties of anesthesiology, intensive care, emergency medicine, and surgery has evolved from discrete, office-based echocardiographic examinations to the real-time or point-of-care clinical assessment and interventions. "Goal-focused" transthoracic echocardiography is a limited scope (as compared with comprehensive examination) echocardiographic examination, performed by the treating clinician in acute care medical practice, and is aimed at addressing specific clinical concerns. In the future, the practice of surface ultrasound will be integrated into the everyday clinical practice as ultrasound-assisted examination and ultrasound-guided procedures. This evolution should start at the medical student level and be reinforced throughout specialist training. The key to making ultrasound available to every physician is through education programs designed to facilitate uptake, rather than to prevent access to this technology and education by specialist craft groups. There is evidence that diagnosis is improved with ultrasound examination, yet data showing change in management and improvement in patient outcome are few and an important area for future research.

Calcific retinal embolism as an indicator of severe unrecognised cardiovascular disease

OBJECTIVE

To describe the association between calcific retinal embolism (CRE) and cardiac valve stenosis.

DESIGN AND SETTING

Retrospective chart review of patients with clinical criteria for CRE.

PATIENTS

24 patients with CRE who underwent two dimensional echocardiography between 1976 and 1998.

RESULTS

Nine patients (38%) had calcific valve stenosis, which was haemodynamically severe in five patients (four aortic and one mitral), four of whom had no cardiac symptoms. Six patients underwent surgical intervention (aortic valve replacement in three patients, mitral and aortic valve replacement in one patient, removal of calcific cardiac pseudotumour in one patient, and carotid endarterectomy in one patient).

CONCLUSIONS

CRE may be the presenting feature of otherwise asymptomatic, clinically important underlying cardiovascular disease and, in particular, haemodynamically severe calcific valve stenosis.

The challenge of defining normality for human mitral and aortic valves: geometrical and compositional analysis

Advances in digital imaging technology and in tools for obtaining detailed quantitation of morphological features have facilitated a new approach to pathological assessment of many tissues, including heart valves. In the present study, we quantitatively examined the tissue geometry and composition of structurally normal mitral and aortic valves removed at autopsy or surgery from patients aged 15-84 years. Through univariate analyses of quantitative variables, we have determined which features change distinctively with age. The anterior mitral valve leaflet (AMV) underwent a statistically significant decrease in area of the valve proper and an increase in the number of superficial tissue accumulations called onlays as the patients aged. For all geometric variables measured in the aortic valve, increases were seen with age, leading to a thicker valve, with enlargement of the valve proper and onlays, and with changes in the number of onlays. The mitral valve proper, composed largely of collagen in younger individuals, showed significant increases in glycosaminoglycans and elastin and a relative decrease in collagen with age. The compositional characteristics of the aortic valve proper were similar to those of the mitral valve, with a dramatic relative increase in elastin and a decrease in collagen with age. Valve onlays, when present, were similar in composition to the valve proper for both valves. Our findings regarding normal valve tissue composition, when taken in the context of geometrical features, and together with evidence of age-related changes in the relative amounts of specific constituents, provide a basis on which to analyze human heart valves affected by various known or putative diseases.

Planimetry and transthoracic two-dimensional echocardiography in noninvasive assessment of aortic valve area in patients with valvular aortic stenosis

OBJECTIVES

The aim of this study was to evaluate the reliability of transthoracic two-dimensional echocardiography in measuring aortic valve area (AVA) by planimetry.

BACKGROUND

Planimetry of AVA using two-dimensional transesophageal echocardiographic images has been reported to be a reliable method for measuring AVA in patients with aortic stenosis. Recent advances in resolution of two-dimensional echocardiography permit direct visualization of an aortic valve orifice from the transthoracic approach more easily than before.

METHODS

Forty-two adult patients with valvular aortic stenosis were examined. A parasternal short-axis view of the aortic valve was obtained with transthoracic two-dimensional echocardiography. AVA was measured directly by planimetry of the inner leaflet edges at the time of maximal opening in early systole. AVA was also measured by planimetry using transesophageal echocardiography, by the continuity equation and by cardiac catheterization (Gorlin formula).

RESULTS

In 32 (76%) of the 42 study patients, AVA could be detected by using the transthoracic planimetry method. There were good correlations between results of transthoracic two-dimensional echocardiographic planimetry and the continuity equation (y = 0.90x + 0.09, r = 0.90, p < 0.001, SEE = 0.09 cm2), transesophageal echocardiographic planimetry (y = 1.05x - 0.02, r = 0.98, p < 0.001, SEE = 0.04 cm2) and the Gorlin formula (y = 1.02x + 0.05, r = 0.89, p < 0.001, SEE = 0.10 cm2).

CONCLUSIONS

Transthoracic two-dimensional echocardiography provides a feasible and reliable method in measuring AVA in patients with aortic stenosis.

Doppler echocardiographic methods to estimate severity of aortic stenosis

The continuity equation should be regarded as the Doppler echocardiographic gold standard for estimation of valve area in patients with aortic stenosis, but a quick, easy, and inexpensive screening test may be desirable in an era of medical cost containment. Aortic valve leaflet separation could be used as such a test. In fact, it could prove especially useful in cases where calculations using the continuity equation or the fractional shortening-velocity ratio are problematic.

Balloon dilatation of the aortic valve for inoperable aortic stenosis

The place of balloon dilatation of the aortic valve in the treatment of calcific aortic stenosis is controversial. Thirty two patients (mean age 76) in whom valve replacement was contraindicated were followed up for three to 24 months (mean 8); 25 were in functional class III or IV according to the New York Heart Association's classification. Major complications of the procedure occurred in four patients. Echocardiography and Doppler studies were performed before operation and before discharge in 28 patients, and the area of the valve was measured again six to 50 (mean 23) weeks after operation in 11 patients. The peak to peak aortic pressure gradient fell from a mean of 65 (SD 24) to 46 (20) mm Hg, but the area of the aortic valve, measured by Doppler echocardiography, in 18 patients showed a modest but significant increase, from 0.61 (0.16) to 0.74 (0.23) cm2. One month after dilatation, 29 patients were alive, of whom 17 had improved symptoms. Only two had lasting clinical benefit. Sixteen patients died, 12 of a cardiac cause. The estimated one year survival rate was 49%. Six patients underwent or required valve replacement because of persisting symptoms. In view of its limited long term efficacy balloon dilatation of the aortic valve should be used only for patients with severe symptoms whose life expectancy is limited by other disease or who are considered to be unsuitable for valve replacement. It may have a role in improving the condition of patients who present with cardiogenic shock or pulmonary oedema before valve replacement is undertaken.

Prediction of severity of aortic stenosis: accuracy of multiple noninvasive parameters

PURPOSE

As newer non-medical techniques are developed to treat older patients with severe aortic stenosis, reliable noninvasive diagnosis of the condition will become increasingly important. For this reason, the accuracy of multiple noninvasive indexes for quantitation of the severity of aortic stenosis was evaluated, relative to catheterization-determined aortic valve area.

PATIENTS AND METHODS

To evaluate the accuracy of multiple noninvasive parameters in assessing the presence and extent of aortic valve narrowing, noninvasive and catheterization correlations of the severity of aortic stenosis were obtained on 121 occasions in 81 patients (mean age, 76 +/- 11 years). Forty patients had studies performed before and after valvuloplasty. Noninvasive studies included the time to one-half carotid upstroke and carotid ejection time, corrected for heart rate, measured from a carotid pulse tracing; M-mode echocardiographic aortic valve excursion; mean pressure gradient across the aortic valve assessed by Doppler technique; the ratio of the peak to mean pressure gradient by Doppler; and Doppler aortic valve area assessed using the following continuity equation: aortic valve area = A X V/V1, where A = left ventricular outflow tract area, V = peak left ventricular outflow tract velocity, and V1 = peak velocity in the aortic stenotic jet. Mean aortic valve gradients and area (calculated using the Gorlin formula) were also assessed at cardiac catheterization.

RESULTS

The correlations between the catheterization measurement of aortic valve area and the various noninvasive measurements were as follows: time to one-half carotid upstroke (r = -0.32, p less than 0.001); corrected left ventricular ejection time (r = -0.24, p less than 0.05); aortic valve excursion (r = 0.51, p less than 0.001); mean gradient by Doppler study (r = -0.44, p less than 0.001); mean gradient by catheterization analysis (r = -0.55, p less than 0.001); peak to mean gradient ratio measured by continuous wave Doppler (r = 0.38, p less than 0.001); and aortic valve area assessed using the Doppler continuity equation (r = 0.85, p less than 0.001).

CONCLUSION

Noninvasive determination of aortic valve area using the continuity equation is an accurate means of assessing the severity of aortic stenosis. Although multiple other noninvasive parameters also correlate with aortic valve area measured at catheterization, there is too much scatter of data points to permit accurate prediction of catheterization aortic valve area in any given patient.

Noninvasive evaluation of aortic stenosis severity utilizing Doppler ultrasound and electrical bioimpedance

Aortic valve area was calculated noninvasively in 30 patients with aortic stenosis undergoing cardiac catheterization. Continuous wave Doppler ultrasound was employed to estimate the mean transvalvular pressure gradient. The mean left ventricular outflow tract flow velocity and cross-sectional area were determined from pulsed Doppler and two-dimensional ultrasound recordings. Electrical transthoracic bioimpedance cardiography performed simultaneously with the ultrasonic study and repeated at the time of catheterization measured heart rate, systolic ejection period and cardiac output. These noninvasive data permitted calculation of aortic valve area using the Gorlin equation (range 0.21 to 1.75 cm2) and the continuity equation (range 0.25 to 1.9 cm2). Subsequent cardiac catheterization showed valve area to range from 0.21 to 1.75 cm2. The mean Doppler pressure gradient estimate was highly predictive of the gradient measured at catheterization (r = +0.92, SEE = 10). Bioimpedance cardiac output measurements agreed with the average of Fick and indicator dye estimates (r = +0.90, SEE = 0.52). Valve area estimates utilizing continuous wave Doppler ultrasound and electrical bioimpedance were superior (r = +0.91, SEE = 0.12) to estimates obtained utilizing the continuity equation (r = +0.76, SEE = 0.29) and were more reliable in the detection of patients with severe aortic stenosis (9 of 11 versus 6 of 11). These data show that 1) electrical bioimpedance methods accurately estimate cardiac output in the presence of aortic stenosis; 2) the hybridized bioimpedance-Doppler ultrasound method yields accurate estimates of aortic stenosis area; and 3) the speed, accuracy and cost-effectiveness of aortic stenosis evaluation may be improved by this hybridized approach.

Echocardiographic assessment of aortic valve area in elderly patients with aortic stenosis and of changes in valve area after percutaneous balloon valvuloplasty

Echocardiographic studies, adequate for analysis of aortic valve area using the continuity equation, were obtained in 31 patients aged greater than or equal to 60 years who were undergoing catheterization for assessment of suspected aortic stenosis. Catheterization-determined aortic valve area was 0.74 +/- 0.30 cm2 (mean +/- SD) and Doppler-determined aortic valve areas were 0.68 +/- 0.27 and 0.65 +/- 0.27 cm2, depending on whether peak or mean velocities, respectively, were entered into the continuity equation. There were significant correlations between both of the Doppler-derived and the catheterization-determined aortic valve areas (r = 0.86, p less than 0.001 for both the continuity equation employing peak velocities and the continuity equation employing mean velocities) which were demonstrated to be linear by F test (catheterization area = -0.03 + 1.13 X Doppler area determined using peak velocities, SEE = 0.163 cm2, p less than 0.001; and catheterization area = -0.02 + 1.16 X Doppler area determined using mean velocities, SEE = 0.165 cm2, p less than 0.001). Both sets of correlations had linear regression parameters meeting the conditions for identity. Significant linear correlations were also noted between the non-invasive measurements of aortic valve excursion, ventricular ejection time, time to one-half carotid upstroke, maximal Doppler velocity and maximal Doppler gradient and catheterization aortic valve area, but the correlations were less tight than those between valve areas determined by catheterization and by Doppler continuity equation. Ten of the patients underwent percutaneous balloon aortic valvuloplasty. There were significant linear correlations between aortic valve areas determined by Doppler and catheterization methods both before valvuloplasty (r = 0.77, p = 0.01; p less than 0.001 by F test, SEE = 0.134 cm2) and after valvuloplasty (r = 0.85, p less than 0.01; p = 0.0001 by F test, SEE = 0.161 cm2). Linear regression parameters met the conditions for identity. There was also a significant linear correlation between catheterization and Doppler measurements of absolute change in aortic valve area (r = 0.79, p less than 0.01; p less than 0.001 by F test, SEE = 0.11 cm2). Aortic valve area can be determined reliably by continuity equation in elderly patients. In addition, results of balloon valvuloplasty, measured by changes in catheterization-determined aortic valve area, are accurately reflected by changes in aortic valve area determined using the continuity equation.

Correlation of continuous wave Doppler velocities with cardiac catheterization gradients: an experimental model of aortic stenosis

The purpose of this study was to use a canine preparation of experimental aortic stenosis to compare estimates of pressure gradient derived from continuous wave Doppler ultrasound with gradients measured directly by catheterization. Aortic stenosis was created in six mongrel dogs by placing an elastic band around the aorta. Eighty-eight different pressure gradients, ranging from 5 to 160 mm Hg, were produced by variable tightening of the aortic band. Pressure gradients were measured by micromanometer-tipped catheters placed in the left ventricle and aorta. Doppler spectral signals were simultaneously obtained using a 2.0 MHz nonimaging transducer placed directly on the surface of the ascending aorta. Doppler and pressure recordings were analyzed using a custom-designed software program to measure maximal instantaneous, mean and peak to peak gradients, as well as ejection and acceleration times. Maximal instantaneous Doppler gradient showed an excellent linear correlation with maximal instantaneous catheterization gradient (r = 0.98, SEE = 5.3 mm Hg). The correlation of Doppler-estimated maximal gradient to peak to peak catheterization gradient was also linear (r = 0.97, SEE = 6.2 mm Hg) but resulted in a systematic overestimation of pressure drop (mean overestimation = 9.0 mm Hg). Measurement of the Doppler gradient at mid-systole resulted in a more accurate correlation with the peak to peak catheterization gradient (r = 0.98, SEE = 6.1 mm Hg) and eliminated the problem of overestimation.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of aortic stenosis by spectral analysis of the murmur

A relation between the peak transaortic pressure gradient and the frequency content of the murmur (r = 0.79) was demonstrated in a prospective "test" set of 50 patients with the clinical diagnosis of aortic stenosis. After heart sounds were recorded and digitized, three segments of the systolic murmur were isolated and analyzed by fast Fourier transform technique. An average frequency spectrum was quantitated by a previously described empiric spectral estimator. Clinical data and spectral ratio were correlated with the transaortic pressure gradient and aortic valve area was calculated from cardiac catheterization data. The best prediction of the transaortic pressure gradient was obtained when a 170 ms murmur segment was analyzed and when the predictive algorithm also included the aortic dimension (r = 0.87). The aortic valve area was poorly predicted (r = -0.48) unless estimates of blood flow and valvular calcification were included in the algorithm (r = 0.84). Further refinement of this technique may provide a non-invasive and clinically useful method for the estimation of aortic valve stenosis.

The role of aortic valve calcium in the detection of aortic stenosis: an echocardiographic study

One hundred fifty-three men (mean age 67.0 +/- 10.0 years) with basal systolic murmurs and aortic valve calcium on the echocardiogram (group II) were studied to assess the relationship between the grade of calcium and severity of aortic valve obstruction. Patients were subdivided into group IIA (hypertension, no coronary artery disease), group IIB (coronary artery disease, no hypertension), group IIC (hypertension and coronary artery disease) and group IID (neither hypertension nor coronary artery disease). Group I consisted of 21 normal age-matched men (mean age 60.5 +/- 10.9 years). Aortic valve calcium was graded as 1+ (63 patients), 2+ (54 patients), or 3+ (36 patients) according to the degree of involvement. Left ventricular wall thickness was greater in group II than in group I, and close correlation between wall thickness parameters and grade of aortic valve calcium was observed for group IID. Of 31 catheterized patients, none of seven with 1+ aortic calcium and 11 of 14 with 3+ calcium had gradients greater than or equal to 50 mm Hg. With 3+ calcium the valve area was 0.8 +/- 0.4 cm2, and with 1+ calcium it was 2.8 +/- 0.7 cm2 (f = 0.0006). The presence of 3+ calcium or grade 2+ calcium combined with a left ventricular ejection time index greater than 433 msec and a left ventricular mass greater than 300 gm was highly suggestive of severe aortic stenosis and could be used to separate patients to be considered for invasive studies from those with benign aortic valve sclerosis.

A new method to calculate aortic valve area without left heart catheterization

Assessment of the severity of aortic stenosis remains a commonly encountered clinical problem. Noninvasive evaluation has to date not proven sufficiently accurate in most cases to permit clinical decision making in the individual patient. Therefore, cardiac catheterization and measurement of the valve area with use of the Gorlin equation remains the standard approach in patients with suspected aortic stenosis. Doppler ultrasound allows direct measurement of blood velocity in cardiac chambers. This technique was used to study 16 patients with suspected aortic stenosis after cardiac catheterization. Aortic valve area (AVA) was calculated with the equation AVA = CO/(SEP X mean velocity), where CO is cardiac output measured by thermodilution and SEP is the systolic ejection period derived from the Doppler tracings. The resulting value was compared with valve area calculated from cardiac catheterization data and an excellent correlation was noted (r = .99). This study demonstrates that Doppler ultrasound can be used to accurately measure aortic valve area without the need for left heart catheterization.

Noninvasive evaluation of the severity of aortic stenosis in adult patients

To determine if a combination of noninvasive variables would be useful in the prediction of the severity of isolated aortic stenosis (AS), 53 patients (mean age 63.4 = 11 years) were evaluated by the following criteria: (1) aortic valve calcification in the plain chest x-ray film; (2) left ventricular hypertrophy by ECG and M-mode echocardiography; (3) faint or absent aortic closure sound; (4) timing of the peak of the systolic murmur; (5) half rise time (T time) of the carotid pulse; and (6) ejection time index. A numeric scoring system and a logistic regression model employing these variables were developed. The total maximum score was 16 points. Sensitivity and specificity for each variable were determined. Patients with clinically evident coronary artery disease (CAD) and significant aortic regurgitation were excluded. All patients underwent hemodynamic studies and coronary arteriography. Thirty-two patients had severe AS (aortic valve area less than 0.75 cm2) and 21 had mild to moderate AS (aortic valve area greater than 0.75 cm2). Significant CAD (greater than or equal to 50% reduction in luminal diameter) was present in 55% of patients. A total score of greater than or equal to 5 occurred in 59% (19 of 32) of patients with severe AS compared to 5% (1 of 21) of patients with mild AS. The presence of subclinical CAD moderately reduced the accuracy of the scoring system principally by its effect upon the timing of the systolic murmur and the ejection time. Combining the scoring system with the presence or absence of symptoms improved the identification of severe AS in patients with a low score.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple aortic root echoes: clinical, radiographic, and angiographic correlations

Multiple diastolic echoes in the aortic root on M-mode echocardiography may represent fibrosis or calcification of the aortic wall, aortic leaflets, or proximal portions of the coronary arteries. In this study, 83 patients with multiple diastolic echoes were evaluated by cardiac fluoroscopy and the incidence of valvular, coronary, and aortic wall calcification was determined. In patients with multiple diastolic echoes who have no evidence of significant aortic stenosis (aortic valve opening less than or equal to 1.0 cm) or aortic insufficiency (fine fluttering of the anterior leaflet of the mitral valve), the presence of multiple diastolic echoes was highly associated with significant coronary artery calcification (64%) with over two-thirds having multivessel involvement. Patients referred for echocardiography who are free of significant aortic stenosis or aortic insufficiency by echocardiographic criteria who are found to have multiple diastolic echoes in the aortic root should be evaluated further for the possible presence of significant multivessel coronary artery disease.

Noninvasive quantification of stenotic semilunar valve areas by Doppler echocardiography

Fourteen patients, aged 1 month to 13 years, with congenital semilunar valve stenosis (11 pulmonary and 3 aortic) were studied for orifice area quantification calculated from a Doppler echocardiographic equation: Area = SV/0.88 X V2 X VET, where SV = stroke volume, V2 = maximal velocity and VET = ventricular ejection time. Results from individual measurements used in this formula and derived area were compared with individual results from cardiac catheterization and valve area derived from the Gorlin formula. Ventricular ejection time by cardiac catheterization ranged from 0.17 to 0.44 second (mean +/- standard deviation [SD] 0.27 +/- 0.09), and by Doppler study from 0.20 to 0.41 second (mean +/- SD 0.29 +/- 0.06) (r = 0.65, standard error of the estimate [SEE] = 0.03, y = 0.149 + 0.528x). Pressure gradient by catheterization ranged from 30 to 125 mm Hg (mean +/- SD 56.6 +/- 33.1), and by Doppler study from 17.6 to 100 mm Hg (mean +/- SD 46.8 +/- 27.9) (r = 0.91, SEE = 8.8, y = 1.23 + 0.904x). Stroke volume was measured by Doppler study simultaneously with cardiac catheterization in nine patients; results at cardiac catheterization with thermodilution measurements (cardiac output/heart rate) ranged from 5.5 to 53.4 cc (mean +/- SD 24.7 +/- 20), and by Doppler study from 5.8 to 46.9 cc (mean +/- SD 23 +/- 18) (r = 0.96, SEE = 3.5). Area quantification was performed in two ways. In Group 1, heart rate-matched stroke volumes from cardiac catheterization were used in the derived equation for Doppler study (all patients). In Group 2, the stroke volume used was that obtained by Doppler study, which was performed simultaneously with cardiac catheterization (nine patients).(ABSTRACT TRUNCATED AT 250 WORDS)

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 assessment of valvular heart disease: surgery without catheterization

Forty-one patients underwent valve surgery at our institution based solely on clinical, M-mode echocardiographic, phonocardiographic, and external pulse recording findings without preoperative cardiac catheterization. Patients with clinical evidence of coronary artery disease were excluded from the study. Preoperatively, 83% of the patients were New York Heart Association functional class III or IV. In all patients, the noninvasive evaluation was considered sufficiently diagnostic of the nature and severity of valvular heart disease to allow surgery without preoperative catheterization. In 23 of 41 cases (group 1), cardiac catheterization was not performed due to the patients' unstable hemodynamic condition at the time surgery was being considered. In the remaining 18 patients (group 2), the probability of obtaining data at catheterization that would significantly affect management decisions was thought to be low, thus not justifying the cost and potential morbidity of this procedure. In all cases, the noninvasive diagnosis was corroborated at operation; there were no unexpected findings nor deaths related to incomplete or incorrect diagnoses. Over a followup period of 4.5 +/- 1.4 years, no patient experienced signs or symptoms of ischemic heart disease. In selected patients without anginal chest pain syndromes, appropriate and successful valve surgery may be performed on the basis of combined clinical and noninvasive evaluation without the need for cardiac catheterization.

Aortic valve systolic flutter as a screening test for severe aortic stenosis

Previous efforts using M-mode echocardiography or 2-dimensional (2-D) echocardiography have not consistently separated patients with and without significant aortic stenosis (AS). We postulated that an aortic valve sufficiently pliant to produce systolic flutter on M-mode echocardiography could exclude significant AS and reviewed the M-mode echocardiograms of 50 consecutive patients (mean age 59 years) catheterized for presumed AS; 2-D echocardiography was also performed in 18 of 50 patients (36%). In 40 of 50 patients (80%) the aortic valve cusps were easily identified on M-mode echocardiography: 19 of 40 (48%) had systolic flutter with a mean aortic valve gradient of 4 +/- 8 mm Hg (mean +/- standard deviation [SD]) and an aortic valve area of 2.8 +/- 0.4 cm2; 21 of 40 (52%) had no systolic flutter with a mean aortic valve gradient of 55 +/- 19 mm Hg and an aortic valve area of 0.7 +/- 0.3 cm2. In the 10 of 50 patients (20%) in whom aortic valve cusps were not clearly identified, the mean aortic valve gradient was 50 +/- 24 mm Hg and the aortic valve area 0.8 +/- 0.4 cm2. Systolic flutter was not seen with an aortic valve gradient greater than 30 mm Hg or an aortic valve area less than 1 cm2. Aortic valve systolic opening by M-mode echocardiography or 2-D echocardiography did not accurately predict the severity of AS. Thus, aortic valve systolic flutter seen on M-mode echocardiography is strong evidence against significant AS, but the absence of systolic flutter does not allow reliable prediction of the severity of AS. The finding of systolic flutter by M-mode echocardiography may be a useful screening test in patients presumed to have AS.

M mode and cross-sectional echocardiographic recognition of fibrosis and calcification of the mitral valve chordae and left ventricular papillary muscles

The echocardiographic appearance of fibrotic thickening and calcification of mitral valve chordae tendineae and left ventricular papillary muscles in 17 patients is described. Pathologic proof of excessive fibrosis or calcification was obtained in five patients. In a sixth patient, calcium was demonstrated on angiography to extend from the chordae into papillary muscle. The characteristic feature of chordal and papillary muscle fibrosis and calcification is the presence of highly echogenic densities best visualized within the left ventricle at a level below the mitral valve leaflets. The more inferior location of these densities, within the body of the left ventricle, enables them to be easily differentiated from densities indicating fibrosis and calcification of the mitral valve anulus. The pattern of chordal and papillary muscle fibrosis and calcification was frequently associated with mitral anular calcification, aortic valve fibrosis or calcification and left atrial enlargement. One patient had rheumatic mitral valve disease. Many patients had mitral regurgitation and most had a history, physical examination and radiologic findings compatible with congestive heart failure. Although the origin and importance of the chordal and papillary muscle changes reported are not known, their frequent association with mitral regurgitation and with congestive heart failure suggests possible interrelations.

Reliability of two-dimensional echocardiography in assessing the severity of valvular aortic stenosis

Two-dimensional echocardiographic studies have shown that maximum long-axis systolic aortic cusp separation (MACS) represents a useful, noninvasive method for estimating severity of valvular aortic stenosis in adults. Although mean values for patients with mild, moderate, and severe aortic stenosis have been clearly separated by this method, overlap occurs among individual patients. In this study, 81 adults with aortic stenosis were studied by two-dimensional echocardiography in the long-axis view. Long-axis assessment of aortic stenosis was obtainable in 93 percent of the patients. Less than 8-mm separation was 97 percent predictive of severe stenosis and 100 percent predictive of moderate or severe stenosis. Eight- to 12-mm had a low predictive value for the severity of stenosis. Greater than 12-mm separation was 96 percent predictive of mild aortic stenosis. Short-axis scans were attempted in 61 of the 81 subjects. Short axis assessment of aortic stenosis based on patterns of leaflet motion was obtainable in 46 of the 61 patients (73 percent) and provided a valuable index of severity. When short-axis scans were included in the assessment of severity in the subgroup of patients with 8- to 12-mm MACS, the predictive value improved greatly (86 percent vs 46 percent). Direct recording of aortic valve area in short-axis was successful in only 13 percent of the subjects. The echo aortic valve area compared with the hemodynamic calculated aortic valve area yielded an r = 0.87.

The use of cross-sectional echocardiography in a general hospital

Three hundred and five patients routinely referred to a general hospital were surveyed to assess the advantages of cross-sectional echocardiography (CSE) over the conventional M mode method. CSE provided a dynamic display of the movement of the heart, particularly left ventricular function, and facilitated the location of cardiac structures. It was valuable in assessing the degree of mitral stenosis and the type of left ventricular outflow obstruction. Mitral valve prolapse, pericardial effusion, intracardiac tumours and congential heart disease were more easily diagnosed than by M mode techniques, but the origin of the basal systolic murmur still remained a problem. It was concluded that the 2 systems were complementary, and that CSE provided important additional information which improved the diagnostic capability of echocardiography.