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

Comparison of 2D vena contracta area with 3D planimetric mitral valve area in rheumatoid mitral valve disease

Rheumatoid valve disease is a general health problem of developing countries, and it mainly affects after the age of 40. Assessment of the correct mitral valve area (MVA) is important for the treatment of rheumatoid valve disease. However, there are contradictions between the three-dimensional (3D) and two-dimensional (2D) methods. A measurement with 3D echocardiography is a more accurate method to measure the MVA. However, in centers without 3D echocardiography, there are some difficulties in the accurate measurement of the MVA. The aim of this study was to assess the value of 2D transesophageal echocardiography (TEE) mitral valve vena contracta area (VCA) in predicting the severity of rheumatoid mitral stenosis (RMS) by comparing 3D planimetry. A total of 24 patients (10 females and 14 males) who were diagnosed with mild/moderate/severe RMS with using pressure half time, mean transmitral gradient, and planimetry methods were included in this study. 3D images were acquired using the 3D zoom and full volume. 2D TEE VCA was measured at an angle of 140° and 60°, which was perpendicular to the former, with color Doppler and the VCA was measured with an ellipsoid area using mathematical formula. There was statistically significant relationship between the measurements of 2D VCA and 3D zoom mode MVA planimetry and MVA full measurements (MVA full volume) (p < 0.01). Calculation of the valvular area after measuring the mitral valve VCA with 2D TEE is a reliable method that is usable in centers without 3D echocardiography.

3D Xplane Echocardiographic Technique for Validation of Mitral Leaflet Separation to Assess Severity of Mitral Stenosis

BACKGROUND

Determining the severity of mitral stenosis (MS) is important for both prognostic and therapeutic implications. Mitral valve area (MVA) calculation techniques have more limitations. Mitral leaflet separation (MLS) is a precise and operator friendly alternative to planimetry. In contrast to previous researchers, we have used a novel 3D Xplane technique to validate MLS for assessing the severity of MS. 3D Xplane is superior for validation of MLS due to simultaneous real time acquisition of MLS in parasternal long-axis view and corresponding MVA by planimetry in parsternal short-axis view.

METHODS

It was a prospective observational single center study. A total of 174 patients with MS were evaluated for MVA estimation by various echocardiographic modalities. Maximum leaflet separation and corresponding planimetered MVA were measured using novel 3D Xplane technique.

RESULTS

With 3D Xplane technique, there was strong positive correlation between planimetered MVA and MLS (R = 0.925, P < 0.001), irrespective of coexisting MR (R = 0.886, P < 0.001) or AF (R = 0.912, P < 0.001). Receiver operating characteristic curves of MLS demonstrated AUC for mild and severe MS to be 0.966 and 0.995, respectively. MLS less than 8.62 mm predicted severe MS with 95.5% sensitivity and 94.7% specificity and MLS more than 12.23 mm predicted mild MS with 93.2% sensitivity and 91.4% specificity.

CONCLUSION

In our study, a strong correlation between planimetered MVA and MLS was found using 3D Xplane technique. 3D Xplane thus validates and standardizes MLS by excluding errors due to temporal and spatial variations which are important limitations of 2D echocardiography.

Measurement of vena contracta width for the assessment of severity of mitral stenosis

This study was designed to test whether vena contracta width (VCW) measured by color Doppler flow could be used to assess the severity of mitral stenosis (MS). A secondary objective was to determine the cut-off value of VCW for the prediction of severe MS. We studied 47 consecutive patients with MS (mean age, 50+/-11 years; 34 females) who did not have more than mild mitral regurgitation. We compared VCW with conventional methods for determining mitral valve area (MVA). Mitral valve area was assessed by one observer using continuity equation (CE), pressure half-time (PHT), and planimetry in the parasternal short axis view. Vena contracta width was measured in the same patients by two observers (blinded to the MVA data) using the apical four-chamber view by color Doppler flow. Vena contracta width measurements were compared with MVA by CE, PHT, and planimetry. The MVA determined by CE, PHT, and planimetry was 1.19+/-0.42, 1.31+/-0.53, and 1.27+/-0.43 cm2, respectively. The VCW in patients with MVA<1 cm2, 1-1.5 cm2, and >1.5 cm2 (calculated by the CE method) was 0.77+/-0.19, 1.13+/-0.16, and 1.36+/-0.24 cm, respectively. Vena contracta width was significantly correlated to MVA by planimetry (r=0.756, P<0.001), PHT (r=0.673, P<0.001), and CE (r=0.813, P<0.001). The VCW of patients with MVA<or=1 cm2 was significantly smaller than that of patients with MVA>1 cm2 determined by the CE method (0.77+/-0.19 vs 1.26+/-0.26, P<0.001). Vena contracta width measurement of 1 cm or less had a sensitivity of 88% and a specificity of 77% for the prediction of severe MS. These results demonstrate that the correlations between VCW and MVA measured by conventional methods were highly significant. In addition, these results suggest that VCW<or=1 cm may indicate the presence of severe mitral stenosis.

A different method for measuring mitral valve area with special emphasis on concomitant aortic regurgitation: A new application of proximal isovelocity surface area method

Measurement of mitral valve area is still a challenge for the echocardiographers. Each method has its own limitations. In this study we assessed a different method and compared it with the other methods. The study included 50 consecutive patients with mitral stenosis. The reference method was planimetry. The suggested method was compared with the pressure half-time method, proximal isovelocity surface area method with and without angular correction, and the continuity method. There was a good correlation between each method and planimetry. The suggested method had the best correlation both for patients with and without aortic regurgitation. The pressure half-time method and continuity method overestimated the mitral valve area for patients with aortic regurgitation, whereas proximal isovelocity surface area method without angular correction overestimated the area in all patients. In conclusion, this method has very good correlation with planimetry. It can be used both in patients with and without aortic regurgitation.

Impact of atrioventricular compliance on pulmonary artery pressure in mitral stenosis: an exercise echocardiographic study

BACKGROUND

The decay of the pressure gradient across a stenotic mitral valve is determined by the size of the orifice and net AV compliance (C(n)). We have observed a group of symptomatic patients, usually in sinus rhythm, characterized by pulmonary hypertension (particularly during exercise) despite a relatively large mitral valve area by pressure half-time. We speculated that this discrepancy was due to low atrial compliance causing both pulmonary hypertension and a steep decay of the transmitral pressure gradient despite significant stenosis. We therefore tested the hypothesis that C(n) is an important physiological determinant of pulmonary artery pressure at rest and during exercise in mitral stenosis.

METHODS AND RESULTS

Twenty patients with mitral stenosis were examined by Doppler echocardiography. C(n), calculated from the ratio of effective mitral valve area (continuity equation) and the E-wave downslope, ranged from 1.7 to 8.1 mL/mm Hg. Systolic pulmonary artery pressure (PAP) increased from 43+/-12 mm Hg at rest to 71+/-23 mm Hg (range, 40 to 110 mm Hg) during exercise. There was a particularly close correlation between C(n) and exercise PAP (r=-0.85). Patients with a low compliance were more symptomatic (P<0.025). Catheter- and Doppler-derived values for C(n), determined in 10 cases, correlated well (r=0.79).

CONCLUSIONS

C(n), which can be noninvasively assessed, is an important physiological determinant of PAP in mitral stenosis. Patients with low C(n) represent an important clinical entity, with symptoms corresponding to severe increases in PAP during stress echocardiography.

Improved assessment of mitral valve stenosis by volumetric real-time three-dimensional echocardiography

OBJECTIVES

This study was performed to determine the feasibility, accuracy and reproducibility of real-time volumetric three-dimensional echocardiography (3-D echo) for the estimation of mitral valve area in patients with mitral valve stenosis.

BACKGROUND

Planimetry of the mitral valve area (MVA) by two-dimensional echocardiography (2-D echo) requires a favorable parasternal acoustic window and depends on operator skill. Transthoracic volumetric 3-D echo allows reconstruction of multiple 2-D planes in any desired orientation and is not limited to parasternal acquisition, and could thus enhance the accuracy and feasibility of calculating MVA.

METHODS

In 48 patients with mitral stenosis (40 women; mean age 61 +/- 13 years) MVA was determined by planimetry using volumetric 3-D echo and compared with measurements obtained by 2-D echo and Doppler pressure half-time (PHT). All measurements were performed by two independent observers. Volumetric data were acquired from an apical view.

RESULTS

Although 2-D echo allowed planimetry of the mitral valve in 43 of 48 patients (89%), calculation of the MVA was possible in all patients when 3-D echo was used. Mitral valve area by 3-D echo correlated well with MVA by 2-D echo (r = 0.93, mean difference, 0.09 +/- 0.14 cm2) and by PHT (r = 0.87, mean difference, 0.16 +/- 0.19 cm2). Interobserver variability was significantly less for 3-D echo than for 2-D echo (SD 0.08cm2 versus SD 0.23cm2, p < 0.001). Furthermore, it was much easier and faster to define the image plane with the smallest orifice area when 3-D echo was used.

CONCLUSIONS

Transthoracic real-time volumetric 3-D echo provides accurate and highly reproducible measurements of mitral valve area and can easily be performed from an apical approach.

Application of proximal isovelocity surface area method to determine prosthetic mitral valve area

BACKGROUND

In this study, we investigated the accuracy of orifice area determination of the prosthetic valve (Biocor) by using proximal isovelocity surface area method (PISA). Thirty-two patients (26 women, 6 men; mean age 44 +/- 8.1 years) were studied. Eleven patients were in normal sinus rhythm and the rest were in atrial fibrillation. Associated valvular lesions were mild aortic regurgitation in 12 patients and moderate tricuspid regurgitation in 19 patients. Sizes of prosthetic valves were 27 to 31, and implantation duration was 4 to 8 years.

METHODS AND RESULTS

We analyzed the flow convergence zone proximal to the valve orifice with the concept of a hemispheric model. Mitral valve area (MVA) calculation was formulated by MVA = 2pi r2 x Va/Vm x (Vm/Vm-Va), where Vm is the maximal mitral velocity and Vm/Vm - Va is a correction factor to account for flattening of isotachs near the prosthetic orifice. MVA calculations by PISA were compared with pressure half-time (PHT), continuity equation (CONT), and color flow area (CFA) methods. Mitral valve areas were 2.17 +/- 0.17 cm2, 2.22 +/- 0.21 cm2, 2.19 +/- 0.22 cm2, and 2.16 +/- 0.17 cm2 in PISA, CFA, PHT, and CONT methods, respectively. Values in the comparison of MVA measurements by different methods were PISA vs PHT, r =.86; PISA vs CFA, r =.77; and PISA vs CONT, r =.89.

CONCLUSIONS

The PISA method gives reliable estimates of large orifices such as prosthetic valves. Although the best correlation was seen with the CONT method, results of this study also confirmed that the PISA method can be applied with reasonable accuracy.

Doppler pressure half-time method of assessing mitral valve area: aortic insufficiency does not adversely affect validity

OBJECTIVES

This study evaluated the effect of aortic insufficiency on the correlation of pressure half-time-derived mitral valve area with each of 2 standards for mitral valve area (planimetry and cardiac catheterization) in a prospectively assembled cohort of patients scheduled for percutaneous balloon mitral commissurotomy.

BACKGROUND

Although Doppler pressure half-time has been validated as a method for assessing mitral valve area, most previous studies have suggested that this noninvasive technique overestimates mitral valve area in the setting of coexistent aortic insufficiency.

METHODS AND RESULTS

Echocardiography and cardiac catheterization were performed on 212 consecutive patients scheduled for percutaneous balloon mitral commissurotomy. After excluding 35 patients who did not have aortography, the rest were divided into a "no aortic insufficiency [AI] group" (n = 146) including those with trivial or no aortic insufficiency at catheterization and an "AI group" (n = 31 ) including those with mild or moderate aortic insufficiency. The pressure half-time mitral valve area tended to slightly underestimate invasive valve area by 0.04 cm2 in the AI group and to slightly overestimate invasive valve area by 0.06 cm2 in the no AI group. This difference between the groups was not statistically significant (P = .13). The pressure half-time mitral valve area tended to underestimate planimetered valve area by 0.11 cm2 in the AI group and by 0.10 cm2 in the no AI group. There was no difference between the 2 groups (P = .94). Potential confounders that could theoretically mask the effect of aortic insufficiency on the pressure half-time (including age, heart rate, blood pressure, left ventricular diastolic pressure, ejection fraction, mitral regurgitation, and atrial fibrillation) were excluded by multivariable analyses.

CONCLUSIONS

The pressure half-time method of determining mitral valve area is not adversely affected by mild to moderate aortic insufficiency. This finding has implications for the utility of this technique in the rheumatic valvular disease population, in which mitral and aortic valve disease frequently coexist.

An enhanced method for measuring cardiac output using Doppler color flow echocardiography

An enhanced method for determining cardiac output using Doppler color flow imaging techniques to measure mitral orifice diameter was developed and validated in an experimental model and in clinical patients. In an in vitro circuit model, color jet width correlated well with actual orifice dimension from 12 to 24 mm (r = 0.99). In the clinical application, mitral valve area was calculated as a X b X pi/4 where a and b represent the width of the color flow stream in the mitral orifice just distal to the annulus in apical long-axis (short-diameter) and 4-chamber (90 degrees rotated, long-diameter) views, respectively. Cardiac output was then computed as the product of mitral valve area and time-velocity integral of transmitral flow from the same site. Cardiac output was also measured by thermodilution and conventional echocardiographic methods using diameters and time-velocity integrals from the left ventricular outflow tract. In 30 patients with nonvalvular heart disease, cardiac output measured by thermodilution ranged from 3.40 to 8.40 L/min. Cardiac output was determined in 28 of 30 patients (93%) by the Doppler color flow imaging technique; it ranged from 3.00 to 8.36 L/min and correlated well with thermodilution: y = 0.90x + 0.63, r = 0.91. Cardiac output was determined in 24 of 30 patients by the conventional left ventricular outflow method (80%). The cardiac output measured by the conventional method correlated less closely with thermodilution (r = 0.84), although there was no statistical difference in correlation coefficiencies between the 2 methods. These results indicate that the Doppler color flow imaging technique can be used to enhance the determination of cardiac output by echocardiography, particularly when the conventional method has resulted in technically inadequate recordings.

Accurate assessment of mitral valve area in patients with mitral stenosis by three-dimensional echocardiography

The accuracy of measurements of mitral valve orifice area (MVA) from three-dimensional echocardiographic (3DE) image data sets obtained by a transthoracic or transesophageal rotational imaging probe was studied in 15 patients with native mitral stenosis. The smallest MVA was identified from a set of eight parallel short-axis cut planes of the mitral valve between the anulus and the tips of leaflets (paraplane echocardiography) and measured by planimetry. In addition, MVA was measured from the two-dimensional short-axis view (2DE). Values of MVA measured by 3DE and 2DE were compared with those calculated from Doppler pressure half-time (PHT) as a gold standard. Observer variabilities were studied for 3DE. MVA measured from PHT ranged between 0.55 and 3.19 cm2 (mean +/- SD 1.57 +/- 0.73 cm2), from 3DE between 0.83 and 3.23 cm2 (mean +/- SD 1.55 +/- 0.67 cm2), and from 2DE between 1.27 and 4.08 cm2 (mean +/- SD 1.9 +/- 0.7 cm2). The variability of intraobserver and interobserver measurements for 3DE measurements was not significantly different (p = 0.79 and p = 0.68, respectively); for interobserver variability, standard error of the estimate = 0.25. There was excellent correlation, close limits of agreement (mean difference +/- 2 SD), and nonsignificant differences between 3DE and PHT for MVA measurements (r = 0.98 [0.02 +/- 0.3] and p = 0.6), respectively. There was moderate correlation, wider limits of agreement, and significant difference between 2DE and PHT for MVA measurements (r = 0.89 [0.32 +/- 0.66] and p = 0.002), respectively. This may be related to the difficulties in visualization of the smallest orifice in precordial short-axis views. This study suggests that three-dimensional image data sets, by providing the possibility of "computer slicing" to generate equidistant parallel cross sections of the mitral valve independently from physically dictated ultrasonic windows, allow accurate and reproducible measurement of the MVA.

Measurement of mitral valve area in mitral stenosis: four echocardiographic methods compared with direct measurement of anatomic orifices

OBJECTIVES

This study sought to compare the mitral valve areas of patients with rheumatic mitral valve stenoses as determined by means of four echocardiographic and Doppler methods with those obtained by direct anatomic measurements.

BACKGROUND

There has been no systemic comparison between Doppler-determined valve areas and the true anatomic orifice in a single cohort.

METHODS

In 30 patients with mitral stenosis, the mitral valve areas determined by two-dimensional echocardiographic planimetry, pressure half-time, flow convergence region and flow area were compared with the values directly measured on the corresponding excised specimen by means of a custom-built sizer.

RESULTS

The correlation coefficient was r = 0.95 (SE 0.06, p < 0.0001) for two-dimensional planimetry; r = 0.80 (SE 0.09, p < 0.0001) for pressure half-time; r = 0.87 (SE 0.09, p < 0.0001) for flow convergence region; and r = 0.54 (SD 0.1, p < 0.002) for flow area. Two-dimensional echocardiographic planimetry, pressure half-time, flow convergence region and flow area overestimated the actual anatomic orifice by > 0.3 cm2 in 2, 1, 6 and 0 patients, respectively, and underestimated it by > 0.3 cm2 in 0, 4, 1 and 8 patients, respectively.

CONCLUSIONS

Mitral valve areas determined by two-dimensional planimetry, pressure half-time and proximal flow convergence region reliably correlated with size of the anatomic orifice. The flow area method provided a less reliable correlation.

Transesophageal echocardiography

This article presents an overview of the benefits and efficacy of transesophageal echocardiography (TEE) in the critically ill patient. The echocardiographic evaluation of ventricular function both regional and global, is discussed with special emphasis on ischemic heart disease; assessment of preload, interrogation of valvular heart disease (prosthetic and native) and its complications; endocarditis and its complications; intracardiac and extracardiac masses, including pulmonary embolism; aortic diseases (e.g., aneurysan, dissection, and traumatic tears); evaluation of patent foramen ovale and its association with central and peripheral embolic events; advancements in computer technology; and finally, the effect of TEE on critical care.

Transesophageal echocardiographic evaluation of native valvular disease and repair

Surgery for valvular heart disease corrects systolic or diastolic dysfunction of the mitral, aortic, or tricuspid valves. The intraoperative echocardiographic assessment of the native heart valve is aimed at defining the pathology of valve disease, determining the mechanism of valve dysfunction, and quantitating the degree (grade) of valvular stenosis or insufficiency.

Biplane transesophageal color Doppler echocardiography for assessment of mitral valve area with mitral inflow jet widths

Biplane transesophageal color Doppler echocardiography can image the mitral valve orifice in two orthogonal views. If the maximal stenotic jet width through the mitral valve obtained with the vertical transducer represents the major axis, the stenotic jet width dissected by the horizontal transducer should be the minor axis of the mitral orifice. Thus the mitral valve area can be calculated assuming an oval shape of mitral orifice. Nineteen patients with mitral stenosis were investigated. Maximal mitral stenotic jet width (JW1) was searched on a vertical plane and the jet width from the orthogonal view (JW2) was obtained on a horizontal plane. Mitral valve areas from the color Doppler jet widths were calculated by pi.JW1/2.JW2/2 and compared with those derived from Gorlin's formula. Adequate quality of echocardiographic images could be obtained in all patients for transesophageal color Doppler jet width measurements or Doppler pressure half-time determinations and in 16 of 19 patients for transthoracic planimetery of the mitral orifice at the parasternal short axis. Mitral valve areas derived from biplane transesophageal color Doppler imaging (1.31 +/- 0.53 cm2) were not different from those calculated according to Gorlin's formula from the catheterization data (1.25 +/- 0.50 cm2), those determined by transthoracic echocardiographic planimetery (1.38 +/- 0.5 cm2), or those calculated from the Doppler pressure half-time method (1.32 +/- 0.41 cm2) (difference not significant by analysis of variance). There was a very strong correlation between transesophageal echocardiographic mitral valve areas and those derived from catheterization data (r = 0.94; standard error of the estimate = 0.13 cm2). A similar correlation was obtained for the planimetric echocardiographic method (r = 0.94; standard error of the estimate = 0.14 cm2). A slightly less strong correlation was found between mitral valve areas derived from the Doppler pressure half-time method and those derived from Gorlin's formula (r = 0.83; standard error of the estimate = 0.24 cm2). The pressure half-time method accurately predicted the mitral valve area in most (15/19) patients, but it significantly (> 0.4 cm2) overestimated mitral valve area in two patients with aortic regurgitation and underestimated (< 0.4 cm2) mitral valve area in two patients with left ventricular hypertrophy. Determination of mitral valve area by color Doppler biplane transesophageal echocardiography is an alternative for accurate estimation of mitral valve area and may be most useful in intraoperative monitoring during surgical or balloon mitral commissurotomy or in the case of inadequate imaging quality of transthoracic echocardiography.

Proximal jet size by Doppler color flow mapping predicts severity of mitral regurgitation. Clinical studies

BACKGROUND

Recent studies have shown that many instrument and physiological factors limit the ability of color Doppler total jet area within the receiving chamber to predict the severity of valvular regurgitation. In contrast, the proximal or initial dimensions of the jet as it emerges from the orifice have been shown to increase directly with orifice size and to correlate well with the severity of aortic insufficiency. Only limited data, however, are available regarding the value of proximal jet size in mitral regurgitation, and it has not been examined in short-axis or transthoracic views. The purpose of the present study, therefore, was to evaluate the relation between proximal jet size and other measures of the severity of mitral regurgitation.

METHODS AND RESULTS

In 49 patients, the anteroposterior height of the proximal jet as it emerges from the mitral valve was measured in the parasternal long-axis view; proximal jet width and area were measured in the short-axis view at the same level. Results were compared with regurgitant volume and fraction by pulsed Doppler subtraction of aortic and mitral flows in 47 patients without more than trace aortic insufficiency; with angiographic grade determined within 24 hours in 33 catheterized patients; and with angiographic regurgitant fraction in 13 patients who were in normal sinus rhythm and had no significant aortic and tricuspid insufficiency. Proximal jet height, width, and area correlated well with Doppler regurgitant volume and fraction (r = .86 to .95; SEE = 7.7 to 9.0 mL; 5.9% to 7.3%). Proximal jet size could also be used to distinguish angiographic grades of mitral regurgitation with minimal overlap (P < .0001) and correlated well with angiographic regurgitant fraction (r = .85 to .91; SEE = 4.1% to 5.1%).

CONCLUSIONS

Proximal jet size correlates well with established measures of the severity of mitral regurgitation. It is conveniently available with transthoracic clinical scanning and should be useful in the routine evaluation of patients with mitral regurgitation.

Quantification of tricuspid regurgitation by means of the proximal flow convergence method: a clinical study

Quantitation of valvular regurgitation remains an important goal in clinical cardiology. It has been described previously that with the use of color Doppler flow mapping, simple measurements of apparent jet size do not correlate closely with quantitative regurgitant indices. Recently the proximal flow convergence method has been proposed to quantify valvular regurgitation by analysis of the converging flow field proximal to a regurgitant lesion. Assuming hemispherical convergence, flow rate Q can be calculated as Q = 2 pi r2va, where va is the aliasing velocity at a distance r from the orifice. For maximal accuracy, previously validated correction factors must be used to account for the flattening effect of the isovelocity contours close to the orifice and for the actual sector angle subtended by the valve leaflets (alpha), to yield a flow rate formula Q = 2 pi r2va.(vp/vp - va).(alpha/180), where vp is the orifice velocity obtained by continuous wave Doppler. In 45 patients (35 in sinus rhythm, 10 with atrial fibrillation) with tricuspid regurgitation, regurgitant stroke volume, regurgitant flow rate, and regurgitant fraction were calculated using the proximal flow convergence method and were compared with values obtained by the Doppler two-dimensional echocardiographic method. Regurgitant stroke volumes (SV) calculated by the proximal flow convergence method correlated very closely with values obtained by the Doppler two-dimensional method with r = 0.95 (y = 0.94x + 0.99) and delta SV = -0.3 +/- 5.2 cm3. Regurgitant flow rates (Q) calculated by both methods showed a similar correlation: r = 0.96 (y = 0.97x + 45) and delta Q = 1.6 +/- 429 cm3/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative assessment of lumen area stenosis by Doppler echocardiography and application of continuity equation

Assessment of luminal stenosis plays a central role in the clinical decision makings for patients with heart diseases. To examine the role of Doppler echocardiography in the measurement of stenotic areas, we attempted to determine the mitral valve area and coronary artery stenosis by Doppler technique with a continuity equation. Mitral valve area was determined as a product of aortic or pulmonic annular cross-sectional area and the ratio of time velocity integral of aortic or pulmonic flow to that of the mitral stenotic jet. Mitral valve area determined at catheterization by Gorlin's formula was used as a gold standard. In the determination of coronary artery stenosis, flow velocity at the site prior to the stenotic lesion and that of stenosis was measured by catheter-tipped Doppler flowmeter (3-Fr, 20 MHz). The severity of the stenosis was calculated from the ratio of time-velocity integrals from prestenotic and stenotic segments. In 41 patients with mitral valve stenosis, valve area determined by continuity equation method correlated well with catheterization measurements irrespective the presence of aortic regurgitation (r = 0.91, y = 0.84x + 0.15, P less than 0.01). Of 20 patients with coronary artery disease, flow velocity both at the stenosis and prior to the stenosis could be determined in 13 patients examined. Under these conditions, coronary artery stenosis determined by continuity equation varied from 21%-76%. When these values were compared with those determined by biplane cineangiography, there was good correlation between them (r = 0.83, y = 0.92x - 0.45, P less than 0.01). These results demonstrate that Doppler-derived luminal area stenosis is applicable to assess the severity of the stenotic lesions, providing further information which cannot be obtained by the conventional methods, although several limitations should further be resolved.