Effect of aortic regurgitation on the assessment of mitral valve orifice area by Doppler pressure half-time in mitral stenosis

Evaluation of the severity of mitral stenosis by continuous-wave Doppler pressure half-time measurement is now well established. However, few data exist regarding the effect of aortic regurgitation (AR) on the validity of this method. Therefore, 73 patients were studied in whom cardiac catheterization and Doppler echocardiographic examinations were performed. Mitral valve orifice area was determined by the Gorlin equation, 2-dimensional echocardiography and Doppler pressure half-time. Doppler pressure half-time and catheterization estimates of mitral valve area correlated well (r = 0.85) in patients without significant mitral regurgitation. This correlation was maintained in patient subgroups with and without significant (at least 2+) AR (r = 0.86 and 0.83, respectively). Similarly, Doppler and 2-dimensional echocardiographic assessment of mitral valve area showed a strong correlation (r = 0.84). Again, the correlation between the 2 methods was similar in patients with and without significant AR (r = 0.86 and 0.82, respectively). Thus, Doppler pressure half-time estimates of mitral valve orifice area are accurate even in patients with AR.     

A comparison of the assessment of mitral valve area by continuous wave Doppler and by cross sectional echocardiography.

Transmitral pressure half time (PHT) was assessed by continuous wave Doppler in 44 patients with rheumatic mitral valve stenosis (14, pure mitral valve stenosis; 15, combined mitral stenosis and regurgitation; and 15 with associated aortic valve regurgitation). The mitral valve area, derived from transmitral pressure half time by the formula 220/pressure half time, was compared with that estimated by cross sectional echocardiography. The transmitral pressure half time correlated well with the mitral valve area estimated by cross sectional echocardiography. The correlation between pressure half time and the cross sectional echocardiographic mitral valve area was also good for patients with pure mitral stenosis and for those with associated mitral or aortic regurgitation. The regression coefficients in the three groups of patients were significantly different. Nevertheless, a transmitral pressure half time of 175 ms correctly identified 20 of 21 patients with cross sectional echocardiographic mitral valve areas less than 1.5 cm2. There were no false positives. The Doppler formula significantly underestimated the mitral valve area determined by cross sectional echocardiography by 28(9)% in 19 patients with an echocardiographic area greater than 2 cm2 and by 14.8 (8)% in 25 patients with area of less than 2 cm2. In thirteen patients with pure mitral valve stenosis Gorlin's formula was used to calculate the mitral valve area. This was overestimated by cross sectional echocardiography by 0.16 (0.19) cm2 and underestimated by Doppler by 0.13 (0.12) cm2. Continuous wave Doppler underestimated the echocardiographic mitral valve area in patients with mild mitral stenosis. The Doppler formula mitral valve area = 220/pressure half time was more accurate in predicting functional (haemodynamic) than anatomical (echocardiographic) mitral valve area.     

A comparison of the assessment of mitral valve area by continuous wave Doppler and by cross sectional echocardiography

Transmitral pressure half time (PHT) was assessed by continuous wave Doppler in 44 patients with rheumatic mitral valve stenosis (14, pure mitral valve stenosis; 15, combined mitral stenosis and regurgitation; and 15 with associated aortic valve regurgitation). The mitral valve area, derived from transmitral pressure half time by the formula 220/pressure half time, was compared with that estimated by cross sectional echocardiography. The transmitral pressure half time correlated well with the mitral valve area estimated by cross sectional echocardiography. The correlation between pressure half time and the cross sectional echocardiographic mitral valve area was also good for patients with pure mitral stenosis and for those with associated mitral or aortic regurgitation. The regression coefficients in the three groups of patients were significantly different. Nevertheless, a transmitral pressure half time of 175 ms correctly identified 20 of 21 patients with cross sectional echocardiographic mitral valve areas less than 1.5 cm2. There were no false positives. The Doppler formula significantly underestimated the mitral valve area determined by cross sectional echocardiography by 28(9)% in 19 patients with an echocardiographic area greater than 2 cm2 and by 14.8 (8)% in 25 patients with area of less than 2 cm2. In thirteen patients with pure mitral valve stenosis Gorlin's formula was used to calculate the mitral valve area. This was overestimated by cross sectional echocardiography by 0.16 (0.19) cm2 and underestimated by Doppler by 0.13 (0.12) cm2. Continuous wave Doppler underestimated the echocardiographic mitral valve area in patients with mild mitral stenosis. The Doppler formula mitral valve area = 220/pressure half time was more accurate in predicting functional (haemodynamic) than anatomical (echocardiographic) mitral valve area.     

Determination of the severity of mitral stenosis by hemodynamic and echocardiographic parameters]

M-Mode and two-dimensional echocardiographic examinations were performed in 70 patients with pure or prevailing mitral stenosis. Mitral valve excursion, mitral valve opening area (MVOAe) and diastolic E-F slope were determined and compared with the gradient across the valve and the opening area obtained during cardiac catheterization. Mitral valve excursion and E-F slope showed mean values of 1.71 cm and 1.98 cm/sec. respectively and were indicative of a stenosed mitral valve. Correlation between E-F slope and gradient with MVOAe was poor. The correlation coefficient was r = +0.56 and r = 0.34 resp. MVOAe compared favorably to the mitral valve area determined at cardiac catheterization (r = + 0.96) and the gradient across the mitral valve (r = 0.90)9 We conclude: 1. Determination of the mitral valve opening area by means of two-dimensional echocardiography represents a valuable addition in the assessment of the severity of mitral stenosis. 2. M Mode echocardiography indicates the presence, but not the severity of mitral stenosis. 3. Computerized planimetry is superior to the manually planimetered opening area and represents a reproducible, exact and time-saving procedure.     

Effect of atrial fibrillation and mitral regurgitation on calculated mitral valve area in mitral stenosis

Forty-nine patients with mitral stenosis (MS) were studied by Doppler echocardiography and 2-dimensional (2-D) echocardiography to assess the ability of Doppler ultrasound to accurately measure mitral valve orifice area and to assess whether atrial fibrillation (AF) or mitral regurgitation (MR) affected the calculation. Twenty-four patients underwent cardiac catheterization. Mitral valve area by Doppler was determined by the pressure half-time method. Mean mitral valve area of all 49 patients by Doppler and 2-D echocardiography correlated well (r = 0.90). There was good correlation between Doppler and 2-D echocardiography in patients with pure MS in sinus rhythm (r = 0.88), in patients with MR (r = 0.93) and in patients with AF (r = 0.96). In the 7 patients with pure MS in sinus rhythm, there was good correlation between Doppler, 2-D echocardiography and cardiac catheterization (r = 0.95). In patients with either MR or AF, cardiac catheterization appeared to underestimate mitral valve orifice compared with both Doppler and 2-D echocardiography (p less than 0.05). Doppler echocardiography can estimate valve area in patients with MS regardless of the presence of MR or AF.     

Methodologic issues in clinical evaluation of stenosis severity in adults undergoing aortic or mitral balloon valvuloplasty. The NHLBI Balloon Valvuloplasty Registry.

Although both catheterization and Doppler measures of valvular stenosis severity have been validated, each has specific advantages and limitations, particularly in the setting of balloon valvuloplasty. Invasive valve area and mean pressure gradient recorded immediately before and after aortic (n = 589) or mitral (n = 608) catheter balloon valvuloplasty were compared with Doppler valve area and mean pressure gradient recorded less than 30 days before and 24 to 72 hours after the procedure. For aortic stenosis, Doppler valve area ranged from 0.1 to 1.4 cm2 before and 0.2 to 2.3 cm2 after catheter balloon valvuloplasty. Doppler and invasive aortic valve areas differed by less than or equal to 0.5 cm2 in 99% and by less than 0.2 cm2 in 92% of patients. Linear correlation was higher before versus after catheter balloon valvuloplasty, for both valve area (r = 0.49 vs r = 0.35, p = 0.01) and mean pressure gradient (r = 0.64 vs r = 0.50, p = 0.01). Group mean invasive valve area was slightly smaller before (0.50 vs 0.59 cm2, p less than 0.0001) but was not different after (0.80 vs 0.78 cm2, p = 0.16) catheter balloon valvuloplasty. Variables affecting the valve area differences were cardiac output, aortic regurgitation, heart rate and blood pressure. Mean pressure gradient differences were related to echo quality, blood pressure and mitral regurgitation. For mitral stenosis, 2-dimensional echocardiographic valve area ranged from 0.4 to 2.8 cm2 before and 0.7 to 3.8 cm2 after catheter balloon valvuloplasty. Two-dimensional echocardiography and invasive mitral valve areas differed by less than or equal to 0.5 cm2 in 96% and by less than 0.2 cm2 in 81% of cases. Linear correlation was not different before versus after catheter balloon valvuloplasty for two-dimensional echocardiographic valve area (r = 0.40 vs 0.36), pressure halftime valve area (r = 0.31 vs 0.32) or mean pressure gradient (r = 0.55 vs r = 0.46). Group mean 2-dimensional echocardiography and pressure halftime valve areas were larger than invasive valve areas before (1.09 vs 1.02 cm2, p = 0.001) and smaller after (1.71 vs 2.02 cm2, p less than 0.0001) catheter balloon valvuloplasty. Important variables affecting the differences were mitral regurgitation, interatrial shunt, cardiac output and heart rate. Nonsimultaneous studies, differing volume flow measurements, and the underlying accuracy of each technique largely account for discrepancies between these methods. The clinical use of each will depend on its ability to predict long-term patient outcome.     

Correlation between cardiac catheterization and echocardiography in assessing the severity of mitral stenosis

During a 12-mth period 162 consecutive patients with mitral stenosis underwent examination by M-mode as well as cross-sectional echocardiography. The mitral valve area was measured by cross-sectional echocardiography and the severity of mitral stenosis by M-mode echocardiography. Out of the total, 69 patients underwent left and right heart catheterization and in 53 of these the mitral valve area was calculated. A correlation of r = 0.92 for the mitral valve area was found between sector scan echocardiography and cardiac catheterization, whereas the correlation between M-mode echocardiography and catheterization yielded a result of only r = 0.38.Thus the assessment of the severity of mitral stenosis by cross-sectional echocardiography is a reliable alternative to cardiac catheterization.     

Assessment of rheumatic mitral valve disease. Value of echocardiography in patients clinically suspected of predominant stenosis.

The value of echocardiography as compared with cardiac catheterisation was evaluated prospectively in 33 consecutive patients clinically suspected of predominant mitral stenosis. Patients with clinical signs of accompanying mitral regurgitation, no matter how severe, and patients with clinical findings indicating insignificant aortic valve disease were included. Critical mitral stenosis was defined by a valve area of less than or equal to 1 cm2. Severe mitral regurgitation was diagnosed by echocardiography on the basis of left ventricular dilatation (more than 3.2 cm/m2 at end-diastole) if not explained otherwise. Significant aortic valve disease was suspected in cases with aortic valve deformity and left ventricular dilatation or hypertrophy as defined by echocardiography. Mitral valve area by echocardiography correlated well with mitral valve area calculated from catheterisation data and a good interobserver correlation was found for echocardiographic measurement. Mitral stenosis, critical or non-critical, may mask significant coexistent valve lesions; echocardiography failed to discover severe mitral regurgitation requiring valve replacement in two patients with non-critical stenosis, and significant aortic regurgitation needing valve replacement was underestimated in one patient with critical mitral stenosis. A correct echocardiographic classification with respect to surgery, however, was obtained in: (1) all patients with clinically pure mitral stenosis (nine patients), and (2) all patients with combined mitral stenosis and regurgitation when either critical stenosis or severe regurgitation was found at echocardiography (12 patients). It thus appears that two out of three patients with mitral valve disease in whom the clinical findings indicate predominant stenosis can be correctly evaluated with the echocardiogram.     

Doppler echocardiographic measurement of aortic valve area in aortic stenosis: a noninvasive application of the Gorlin formula

Thirty adult patients with aortic stenosis had Doppler echocardiography within 1 day of cardiac catheterization. Noninvasive measurement of the mean transaortic pressure gradient was calculated by applying the simplified Bernoulli equation to the continuous wave Doppler transaortic velocity recording. Stroke volume was measured noninvasively by multiplying the systolic velocity integral of flow in the left ventricular outflow tract (obtained by pulsed Doppler ultrasonography) by the cross-sectional area of the left ventricular outflow tract (measured by two-dimensional echocardiography). Non-invasive measurement of aortic valve area was calculated by two methods. In method 1, the Gorlin equation was applied using Doppler-derived mean pressure gradient, cardiac output and systolic ejection period. Method 2 used the continuity equation. These noninvasive measurements were compared with invasive measurements using linear regression analysis, and mean pressure gradients correlated well (r = 0.92). Aortic valve area by either noninvasive method also correlated well with cardiac catheterization values (method 1, r = 0.87; method 2, r = 0.88). The sensitivity of Doppler detection of critical aortic stenosis was 0.86, with a specificity of 0.88 and a positive predictive value of 0.86. Cardiac output measured nonsimultaneously showed poor correlation (r = 0.51). Doppler echocardiography can distinguish critical from noncritical aortic stenosis with a high degree of accuracy. Measurement of aortic valve area aids interpretation of Doppler-derived mean pressure gradient data when the gradients are in an intermediate range (30 to 50 mm Hg).     

Comparison of two-dimensional and Doppler echocardiography and intracardiac hemodynamics for quantification of mitral stenosis

Forty-three patients with mitral stenosis (MS) were studied to assess the relation of catheter-derived pressure gradient half-time (P 1/2), mitral valve areas (calculated by the Gorlin formula and 2-dimensional echocardiography [2-D echo]) to mitral valve areas derived from Doppler pressure half-time (T 1/2) in order to establish an accurate line-drawing method in nonlinear velocity tracings and to revalidate the use of the empiric constant of 220 ms as the T 1/2 that predicts a 1.0-cm2 mitral valve area. Mitral valve area could be quantified by 2-D echo in 39 of 43 patients and by Doppler in 31 of 34 patients, for a success rate of 91%. A reliable technique for measuring Doppler T 1/2 in nonlinear Doppler velocity tracings was a "mid-diastolic" line-drawing method, validated with the "anatomic" mitral valve area by 2-D echo (r = 0.89) and with the "hemodynamic" mitral valve area by the Gorlin formula (in pure MS without regurgitation) (r = 0.95). By both Doppler T 1/2 and hemodynamic P 1/2, the use of 220 ms to predict a mitral valve area of 1.0 cm2 was validated. Each T 1/2 and P 1/2 had an exponential inverse relation to the mitral valve area by the Gorlin formula in pure MS. Doppler and 2-D echocardiographic quantification of MS are complementary. Reliable measurement of T 1/2 in nonlinear velocity tracings is achieved by a mid-diastolic line-drawing method and use of the equation 220 ms/T 1/2 = mitral valve area accurately quantifies MS.     

Comparative accuracy of two-dimensional echocardiography and Doppler pressure half-time methods in assessing severity of mitral stenosis in patients with and without prior commissurotomy

This study was undertaken to compare the accuracies of the two-dimensional echocardiographic (2DE) and Doppler pressure half-time methods for the noninvasive estimation of cardiac catheterization measurements of mitral valve area in patients with pure mitral stenosis both with and without a previous commissurotomy. Data were retrospectively obtained from 74 consecutive patients who underwent cardiac catheterization within a 30 month period for evaluation of mitral stenosis, and who had two-dimensional echocardiograms performed before catheterization. Six patients (8.1%) had technically inadequate 2DE images and their data were excluded from analysis. Two of these patients had undergone commissurotomy, while the remaining four had not. Continuous-wave Doppler echocardiographic examinations were attempted in 45 patients and adequate measurements of pressure half-times were obtained in all patients studied. Mitral valve area by two-dimensional echocardiography was measured as the planimetered area along the inner border of the smallest mitral orifice visualized during short-axis scanning, while pressure half-time was calculated as the interval between the peak transmitral velocity and velocity/square root 2 as measured from the envelope of the Doppler spectral signal. Calculations from catheterization represented the minimal valve area at rest as derived from the Gorlin formula with the use of pressure gradients and thermodilution measurements of cardiac output. Thirty-seven of the patients had had a previous mitral commissurotomy a mean of 11.2 +/- 5.4 years before, while the remaining 37 patients were previously unoperated. Mean valve area as determined at catheterization for the total group of patients ranged from 0.37 to 2.30 cm2 (mean = 1.08 +/- 0.42 cm2).(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemodynamic evaluation of porcine bioprostheses in the mitral position by doppler echocardiography

Twenty-four patients with porcine bioprostheses in the mitral position were studied by Doppler echocardiography followed by cardiac catheterization within 24 hours. Doppler mean diastolic mitral valve gradient was calculated by a 3-point method and mitral valve area was determined by the pressure half-time method. Data from Doppler echocardiography and cardiac catheterization were compared. There was a strong correlation between Doppler echocardiography and catheterization-determined mean diastolic gradient: r = 0.9, standard error of estimate (SEE) = 1.4 mm/Hg (regression equation y = 0.63x + 1.41), p <0.001. There was also a strong correlation between Doppler echocardiography and catheterization-determined mitral valve area: r = 0.86, SEE = 0.18 cm² (regression equation y = 0.64x + 0.52), p <0.001. Fourteen patients whose valvular function was considered normal by clinical evaluation had Doppler-calculated mean diastolic gradients of 4.5 to 9.5 mm Hg (mean 6.5 ± 1.4); the Doppler-determined valve area was 1.15 to 2.0 cm² (mean 1.54 ± 0.3). Ten patients had a malfunctioning bioprosthesis, 7 had severe mitral regurgitation and 3 had stenosis. Valvular malfunction in all 10 patients was detected by Doppler echocardiography and confirmed by catheterization and angiocardiography. Nine patients underwent reoperation. Doppler hemodynamic evaluation of porcine bioprostheses in the mitral position provided noninvasive information comparable to that obtained by cardiac catheterization.     

Estimation of mitral valve area from regression analysis of the pressure gradient in mitral stenosis.

Estimation of mitral valve area (MVA) in the cardiac catheterization laboratory is prone to pitfalls because of the time required for calculations and inaccuracies in the measurement of cardiac output. Because the rate of decrease in the mitral gradient directly correlates with the severity of mitral stenosis, an on-line estimate of MVA at the time of catheterization may be possible with regression analysis of digitized pressure recordings. A total of 61 comparisons of mitral gradient measurements and MVA were obtained in 37 patients at diagnostic catheterization and in 24 patients after balloon mitral valvotomy. Linear and nonlinear regression parameters yielded pressure half-time values and empiric constants similar to those used in Doppler echocardiography for estimation of MVA. The correlations derived from linear analysis were as good as those obtained from nonlinear analysis: from linear analysis, MVAregression = 0.79.MVAGorlin -0.03; r2 = 0.64, p = 0.0001; and from double exponential analysis, MVAregression = 0.86.MVAGorlin -0.07; r2 = 0.74; p = 0.0001. The correlations were not significantly affected by the presence of mild to moderate mitral regurgitation or whether they were obtained after balloon valvotomy. In summary, linear regression analysis yields accurate estimates of MVA despite the theoretical superiority of nonlinear methods. On-line digital analysis of mitral gradient tracings may thus be useful at the time of diagnostic cardiac catheterization or balloon mitral valvotomy to assess the severity of mitral stenosis and the response to interventions.     

Doppler sonographic determination of the degree of severity of mitral valve stenoses

Using combined two-dimensional echocardiography and Doppler technique in 30 patients with pure mitral valve stenosis or combined valve disease with prevailing mitral stenosis, the mitral valve area and diastolic pressure gradient were determined, and compared to the invasively recorded values obtained during heart catheterization. Four patients were examined by Doppler ultrasound before and after mitral valve replacement. The determination of the mitral valve area was performed 1) invasively by means of the formula derived by Gorlin (and measured between 0.5 and 2.9 cm2), 2) by means of planimetry by integration of the two-dimensional echo in the short-axis view (between 0.7 and 2.8 cm2), and 3) by Doppler ultrasound based on the formula 220/t1/2, whereby the pressure half-time was obtained by dividing maximum flow velocity by square root 2. Here, the mitral valve area was between 0.5 and 2.8 cm2. The correlation between values obtained invasively and by means of Doppler ultrasound was good (r = 0.86), and compared well to the correlation between two-dimensional echocardiography and heart catheterization (r = 0.88). The best correlation of r = 0.89 was found between the mitral valve areas obtained by Doppler ultrasound and two-dimensional echocardiography. The diastolic pressure gradient was calculated by means of the formula derived from the Bernoulli equation, which is: delta P = 4Vmax2, whereby Vmax equals the maximum transmitral flow velocity. The invasively measured pressure gradients were between 2 and 30 mm Hg, the values obtained by Doppler ultrasound were between 6 and 29 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)     

Application of Doppler color flow imaging to determine valve area in mitral stenosis.

This study was undertaken to examine whether Doppler color flow imaging could accurately estimate the valve area in mitral stenosis. Doppler color flow assessments were performed in both an in vitro model and in 30 patients with mitral stenosis undergoing cardiac catheterization. In the experimental Doppler study using a circuit model, color jet width correlated well with actual orifice diameter (r = 0.99). In the clinical Doppler study, the mitral valve orifice was assumed to be elliptic and the mitral valve area was calculated from the following equation: (pi/4) (a x b), where a = color jet width at the mitral valve orifice in the apical long-axis view (short diameter) and b = the width in the 90 degrees rotated view (long diameter). Mitral valve area was also determined by two-dimensional echocardiography and the pressure half-time method, and the results for all three noninvasive methods were compared with those obtained at cardiac catheterization. By Doppler color flow imaging, mitral valve area could be determined in all patients and there was a significant correlation between the Doppler jet and catheterization estimates of mitral valve area (r = 0.93). Valve area determined by two-dimensional echocardiography correlated well with catheterization measurements in 26 patients (r = 0.84). However, the area could not be determined in 4 (13%) of the 30 patients because of technical problems. Although there was a fair correlation between the valve area determined by the pressure half-time method and catheterization (r = 0.79), this method tended to overestimate valve area in patients with aortic regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serial assessment of mitral regurgitation by pulsed Doppler echocardiography in patients undergoing balloon aortic valvuloplasty

Mitral regurgitation was serially assessed by pulsed Doppler echocardiography in 144 patients undergoing balloon aortic valvuloplasty for symptomatic aortic stenosis. Regurgitant scores of 0, 1, 2 and 3 were assigned to pulsed Doppler patterns corresponding to no, mild, moderate and severe mitral regurgitation, respectively. Before balloon aortic valvuloplasty, mitral regurgitant score correlated significantly (p less than 0.005) but weakly with aortic valve area (r = -0.24), left ventricular ejection fraction (r = -0.34) and left ventricular systolic pressure (r = 0.23). There was no significant correlation between mitral regurgitation and either mean catheterization or mean Doppler aortic valve gradient. Balloon aortic valvuloplasty produced significant decreases in both catheterization and Doppler mean transvalvular aortic valve gradients (56 +/- 19 to 31 +/- 12 and 60 +/- 19 to 48 +/- 16 mm Hg, respectively; both p less than 0.0001) and a significant increase (p less than 0.0001) in aortic valve area assessed by catheterization (0.6 +/- 0.2 to 0.9 +/- 0.3 cm2). Left ventricular ejection fraction did not change, but cardiac output increased (p less than 0.001) and pulmonary capillary wedge pressure decreased (p less than 0.0001). Pulsed Doppler findings of mitral regurgitation were present in 102 of the 144 patients. Eighty-eight patients had a score compatible with mild or more severe degrees of mitral regurgitation, and 49 had a score indicative of moderate or severe valvular insufficiency. In the entire group of 144 patients, mitral regurgitant score decreased significantly from 1.1 +/- 1.0 to 1.0 +/- 1.0 (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Echocardiography of operated heart. Assessment of results of mitral valvuloplasty

AIM: To assess results of surgery and to elaborate criteria of noninvasive diagnosis of cardiac function in patients with rheumatic mitral disease after reconstructive interventions on mitral valve. MATERIAL: Patients (n=192, mean age 41.2+/-1.2 years) with pure mitral stenosis (76%) and combined mitral valve disease with prevalent stenosis (24%), and 32 practically healthy people (n=32, mean age 36.6+/-3.5 years, control group). METHODS: Comprised transthoracic mono and two-dimensional echocardiography and doppler echocardiography. Results of intracardiac flow study were compared with data of invasive methods of investigation--intraoperative flowmetry and manometry, cardiac catheterization and intraoperative transesophageal echocardiography. RESULTS AND CONCLUSIONS: The following criteria of hemodynamically effective valvuloplasty were established: lowering of mean mitral valve pressure gradient by 54-65%; absence of regurgitation or lowering of mitral valve regurgitation fraction to < or =6% of total stroke volume. Significant increase of left ventricular stroke volume (by 22-27%), increase of mitral valve area (by 164-222%), decrease of left atrial diameter (mean decrease 17%) were also noted.     

Doppler echocardiographic assessment of the valve area in patients with atrioventricular valve stenosis by application of the continuity equation

The orifice area was non-invasively assessed in 19 patients with mitral or mitral and tricuspid stenosis by combined cross-sectional and Doppler echocardiography. Stroke volume was calculated as the product of aortic or pulmonic cross-sectional area and the time velocity integral of the flow across that valve, and the stenotic valve area was obtained as the stroke volume divided by the time velocity integral of the stenotic valve. In addition, the mitral valve area was estimated by the pressure half-time method of Hatle et al. The non-invasive determinations were compared with those calculated by the Gorlin formula at cardiac catheterization. The valve area obtained by combined cross-sectional and Doppler echocardiography showed a close correlation with the Gorlin area, r = 0.90, SEE = 0.13 cm2, n = 20. In contrast, the valve area estimated by the pressure half-time method showed only a moderate correlation with the Gorlin area, r = 0.68, SEE = 0.38 cm2, n = 18, and estimates by this method tended to significantly overestimate the Gorlin area. In conclusion, non-invasive valve area determinations based on combined cross-sectional and Doppler echocardiography can be used to accurately quantify the severity of the lesion in patients with atrioventricular valve stenosis, while determinations by the pressure half-time method may show errors of a magnitude that limits its clinical applicability.     

Doppler echocardiography determination of the pressure gradient and valve orifice area in mitral valve stenosis

Pressure gradient and orifice area of stenosed mitral valves can be determined with Doppler echocardiography using the modified Bernoulli equation and the pressure half-time method, respectively (Figures 1 and 2). There was a close linear correlation between Doppler-echocardiographically determined pressure gradients and valve orifice areas with those obtained by invasive methods. In this study, in 85 patients with mitral stenosis of various severity, the valve orifice areas, as derived by the two methods respectively, correlated well (y = 0.89x + 0.15) with a correlation coefficient r = 0.96 and standard error of the estimate SEE = 0.12 cm2 (Figure 3). The correlation was not influenced by the prevailing cardiac rhythm, ventricular function, left ventricular mass or coexistent mitral or aortic regurgitation (Table 1). Accordingly, the Doppler echocardiographic method also appears applicable in the presence of concomitant mitral and aortic regurgitation which precludes an exact determination of valve orifice area with invasive methods. The Doppler echocardiographic method is currently so well validated that it can be regarded as a reliable noninvasive procedure for determination of the severity of mitral stenosis.     

Determination of the stenotic aortic valve area in adults using Doppler echocardiography

The severity of aortic stenosis was evaluated by Doppler echocardiography in 48 adults (mean age 67 years) undergoing cardiac catheterization. Maximal Doppler systolic gradient correlated with peak to peak pressure gradient (r = 0.79, y = 0.63x + 25.2 mm Hg) and mean Doppler gradient correlated with mean pressure gradient (r = 0.77, y = 0.59x + 10.0 mm Hg) by manometry. The transvalvular pressure gradient is flow dependent, however, and associated left ventricular dysfunction was common in our patients (33%). Thus, of the 32 patients with an aortic valve area less than or equal to 1.0 cm2 at catheterization, 6 (19%) had a peak Doppler gradient less than 50 mm Hg. To take into account the influence of volume flow, aortic valve area was calculated as stroke volume, measured simultaneously by thermodilution, divided by the Doppler systolic velocity integral in the aortic jet. Aortic valve areas calculated by this method were compared with results at catheterization in the total group (r = 0.71). Significant aortic insufficiency was present in 71% of the population. In the subgroup without significant coexisting aortic insufficiency, closer agreement of valve area with catheterization was noted (n = 14, r = 0.91, y = 0.83x + 0.24 cm2). Transaortic stroke volume can be determined noninvasively by Doppler echocardiographic measures in the left ventricular outflow tract, just proximal to the stenotic valve. Aortic valve area can then be calculated as left ventricular outflow tract cross-sectional area times the systolic velocity integral of outflow tract flow, divided by the systolic velocity integral in the aortic jet.(ABSTRACT TRUNCATED AT 250 WORDS)