Analysis of interobserver and intraobserver variation of interpretation of the echocardiographic and Doppler flow determination of cardiac output by the mitral orifice method

The variability of the interpretation by two individuals of a combined echocardiographic and Doppler method of calculating output was studied in 30 normal adults. In each subject three separate cardiac cycles were recorded to calculate maximal mitral valve orifice, the ratio of mean to maximal mitral valve leaflet separation, and the mean flow velocity through the mitral valve. The recordings were digitised twice by two independent observers. Estimates of cardiac output ranged from 3.2 to 8.11 1/min. Analysis of variance showed that interobserver and intraobserver variability for these measurements was 5.8% and 6.1% respectively. It is concluded that the reproducibility for interpreting this non-invasive method is adequate for clinical use in adults with cardiac outputs within the normal range.     

Calculating cardiac output from transmitral volume flow using Doppler and M-mode echocardiography

To simplify transmitral volume flow determination by Doppler echocardiography, a formula for calculating mean mitral valve orifice area using M-mode echocardiography without any 2-dimensional measurements was developed and evaluated in this study. The maximal mitral orifice area was assumed to be circular and its diameter was calculated from the maximal M-mode mitral leaflet separation. The maximal area was multiplied by the mean to maximal anterior mitral leaflet excursion ratio to correct for phasic changes in flow orifice area during ventricular filling. This measurement had a high correlation (r = 0.97, standard error of the estimate + 0.26 cm2) with mean mitral valve orifice area calculated from frame-by-frame analysis of short-axis 2-dimensional echoes in a select group of 10 normal volunteers and 10 patients with cardiomyopathy who had very high quality images of the mitral valve leaflet tips. Cardiac output calculated using the new method for orifice area estimation combined with apex view mitral valve Doppler velocities was then validated in 48 consecutive patients undergoing thermodilution cardiac output determinations with a close correlation between Doppler and thermodilution cardiac output (2.3 to 6.1 liter/min, r = 0.93, standard error of the estimate = 362 ml). The correlation improved when 12 patients with mild mitral insufficiency were excluded (r = 0.95). The M-mode echocardiogram-derived mitral valve orifice method combined with Doppler mitral valve velocities is accurate, easy to perform, has a high success rate and should increase the applicability of Doppler echocardiography for estimation of cardiac output.     

Accuracy of mitral Doppler echocardiographic cardiac output determinations in adults

The Doppler echocardiographic estimation of cardiac output at the mitral valve site is often underestimated in adults with slow heart rates because the mitral valve remains open in mid-diastole when flow is markedly reduced. Therefore we tested several approaches to this measurement in 17 adults with nonvalvular heart disease who had thermodilution catheters in the right side of the heart. Superior correlations with thermal output values were obtained by a new method that excludes mitral orifice measurements during mid-diastole when flow less than 10 cm/sec (r = 0.94) compared with the standard method (r = 0.89). Also, the new method resulted in significantly less underestimation of thermal cardiac output in patients with heart rates less than 70 beats/min (-10%) compared with the standard method (-34%). In addition, use of a constant maximal two-dimensional echocardiographic mitral orifice correction factor of 0.77 with the new method to account for variations in mitral valve orifice during the cardiac cycle, as opposed to 0.68 with the standard method, resulted in similar results as compared with determining individual correction factors from M-mode echoes. We conclude that: (1) the mitral orifice approach is accurate for measuring cardiac output in adult patients with nonvalvular heart disease; (2) a new method that excludes mid-diastolic mitral orifice measurements is superior to the standard method; and (3) use of a constant two-dimensional echocardiographic mitral valve orifice correction factor obviates the need for M-mode echoes.     

The mitral valve orifice method for noninvasive two-dimensional echo Doppler determinations of cardiac output

We developed and validated a mitral valve orifice method for Doppler cardiac output determination. In 15 open-chest dogs, cardiac output was controlled and measured by a roller pump interposed between the right atrium and pulmonary artery as a right-heart bypass. Left heart flows were measured in the open-chest dog model by Doppler measurements at the mitral valve orifice and compared not only to volume flow measured by the roller pump, but to electromagnetic flow meters as well. The maximum mitral valve orifice area was measured off short-axis two-dimensional echocardiographic views by planimetry. The maximal orifice was then adjusted for its diastolic variation in size by calculating a ratio of mean-to-maximal mitral valve separation on a derived M-mode echocardiogram. Flow was sampled parallel to mitral valve inflow in a four-chamber plane. The multiplication of mean flow throughout the cardiac cycle by the mean mitral valve area after correction for diastolic size variation yielded a cardiac output determination that could be compared to the roller pump measurement. Fifty-two cardiac output determinations over roller pump values of 1-5 l/min yielded a high correlation between roller pump flows and Doppler (r = 0.97 +/- 0.23 l/min). Our study shows that the mitral valve orifice provides an accurate site for Doppler cardiac output measurements.     

A comparison between mitral and aortic outputs evaluated by Doppler echocardiography in a group of healthy subjects: false regurgitation

Doppler echocardiography is a potentially useful tool for the non invasive evaluation of cardiac output and, therefore, for the quantitative assessment of valvular regurgitation. The aim of our study was to establish the presence of possible pitfalls in the evaluation of mitral and aortic regurgitant fraction obtained by Doppler echocardiography comparing the cardiac output measured at the level of the mitral and aortic valve. For this purpose 19 healthy volunteers, aged between 14-68 years, were studied. Stroke volume and cardiac output were calculated at the level of the mitral and aortic valve. The methods we used for the measurement of both the mitral and aortic cardiac output had already been validated and presumes that the shape of the valve annulus, is circular. No statistically significant differences were found between the parameters obtained at the two different valvular levels. Furthermore, cardiac output values correlated fairly well (r = 0.83, ESS = 0.78 l/min). In 9 subjects the aortic cardiac output was greater than the mitral one, while in the others mitral cardiac output was greater. The average of the differences between the two cardiac outputs was 0.58 +/- 0.48 l/min with a regurgitation fraction of 9.5 +/- 7.9%. Our results show that the mitral and aortic stroke volume and cardiac output, as measured by Doppler echocardiography (considering a circular shaped valve annulus, are not statistically different and correlate fairly well in our normal subjects. Nevertheless, we observed a certain degree of variability between the mitral and the aortic cardiac output.(ABSTRACT TRUNCATED AT 250 WORDS)     

Feasibility and variability of six methods for the echocardiographic and Doppler determination of cardiac output

The feasibility and the intrinsic variability of six different methods of echocardiographic and Doppler flow determination of cardiac output were analysed in 34 healthy volunteers. Four were excluded because of poor quality echocardiograms. The mean (range) age of the remaining 30 (12 women, 18 men) was 21 years (13-36 years). Cardiac output was calculated by six methods as a product of echocardiographically determined cross sectional area of the aorta (apical and suprasternal views), pulmonary trunk, tricuspid annulus, and mitral annulus (circular and corrected for diastolic variations), and the flow velocity integral measured by Doppler. Cardiac output ranged from 2.79 to 6.56 1/min (4.45 (1.29) 1/min) (mean (SD)). The feasibility of the methods ranged from 87% (26 patients) for the aorta from the suprasternal notch to 100% (30 patients) for the mitral orifice corrected for diastolic variations and for the tricuspid valve. The corresponding results for all 34 individuals were 76% and 88% respectively. Three way analysis of variance was performed in the 23 healthy volunteers in whom all six methods were feasible. Interobserver and intraobserver interpretative variabilities were 6.8% and 5.9% respectively. The intrinsic variability of each single measurement of cardiac output, independently of the observer and the method used, was 25%. Provided the image was suitable for analysis echocardiographic and Doppler flow determination of cardiac output was feasible in most healthy volunteers. But there was significant intrinsic variability for each of different methods. A single value of cardiac output in an individual should be interpreted with caution.     

Feasibility and variability of six methods for the echocardiographic and Doppler determination of cardiac output.

The feasibility and the intrinsic variability of six different methods of echocardiographic and Doppler flow determination of cardiac output were analysed in 34 healthy volunteers. Four were excluded because of poor quality echocardiograms. The mean (range) age of the remaining 30 (12 women, 18 men) was 21 years (13-36 years). Cardiac output was calculated by six methods as a product of echocardiographically determined cross sectional area of the aorta (apical and suprasternal views), pulmonary trunk, tricuspid annulus, and mitral annulus (circular and corrected for diastolic variations), and the flow velocity integral measured by Doppler. Cardiac output ranged from 2.79 to 6.56 1/min (4.45 (1.29) 1/min) (mean (SD)). The feasibility of the methods ranged from 87% (26 patients) for the aorta from the suprasternal notch to 100% (30 patients) for the mitral orifice corrected for diastolic variations and for the tricuspid valve. The corresponding results for all 34 individuals were 76% and 88% respectively. Three way analysis of variance was performed in the 23 healthy volunteers in whom all six methods were feasible. Interobserver and intraobserver interpretative variabilities were 6.8% and 5.9% respectively. The intrinsic variability of each single measurement of cardiac output, independently of the observer and the method used, was 25%. Provided the image was suitable for analysis echocardiographic and Doppler flow determination of cardiac output was feasible in most healthy volunteers. But there was significant intrinsic variability for each of different methods. A single value of cardiac output in an individual should be interpreted with caution.     

Reproducibility of Doppler echocardiographic quantification of aortic and mitral valve stenoses: comparison between two echocardiography centers

Doppler echocardiography has been widely used as a noninvasive method to quantify valvular heart diseases. This study assessed the variability between 2 echocardiography centers concerning 2-dimensional and Doppler echocardiographic results in the quantification of mitral and aortic valve stenoses. Forty-two patients were studied by 2 different echocardiography centers in a blinded, independent fashion. In patients with aortic and mitral valve stenosis, mean and maximal flow velocities were measured. The aortic valve orifice area was calculated according to the continuity equation. Mitral valve orifice area was determined by direct planimetry and by pressure half-time. In patients with an aortic valve stenosis, a close relation between the 2 centers was found for the maximal and mean flow velocities (coefficient of correlation, r = 0.72 to 0.92; coefficient of variation, 3.7 to 7.7%). A close correlation and a small observer variability was found for the flow velocity ratio determined by flow velocities measured in the left ventricular outflow tract and over the stenotic valve (r = 0.88; coefficient of variation, 0.01 +/- 0.009). In contrast, there was a poor correlation between the diameter of the left ventricular outflow tract and the aortic orifice area (r = 0.36 and 0.59, respectively). In patients with a mitral valve stenosis, mean and maximal velocities were closely correlated (r = 0.85 and 0.77, respectively). Velocities were not found to be significantly different between the 2 centers. Variability between the 2 centers for the mitral valve orifice area was 9.8% (2-dimensional echocardiography) and 5.7% (pressure half-time).(ABSTRACT TRUNCATED AT 250 WORDS)     

Determination of the transvalvular gradient using continuous wave Doppler in patients with mitral stenosis. Correlation with the hemodynamic method

In order to assess the reliability of Doppler echocardiography in the determination of mean mitral gradient 38 consecutive patients (pts) affected by rheumatic mitral valve stenosis (MS) were analyzed by continuous wave Doppler echocardiography (CWD). Cardiac catheterization (CATH) was performed within 24 hours from echocardiographic examination. The mean diastolic mitral gradient (MG) at CATH was calculated by planimetry from simultaneously recorded left ventricular and pulmonary artery wedge pressure. The maximal velocity profile through the mitral valve was used to calculate pressure gradient by CWD. A mean mitral gradient was calculated for each patient by the planimetered velocity profile throughout diastole. MG determined by CATH ranged from 6 to 31 mmHg (mean 15.2 +/- 6.0); MG determined by CWD ranged from 4 to 18 mmHg (mean 10 +/- 3.7). The correlation between CWD and CATH by linear regression analysis was: y = 0.53 X + 1.8; r = 0.85; p less than 0.001. Mean % error of CWD in the assessment of MG was 34.7%. In conclusion this study indicates that CWD seems systematically underestimate MG with respect to CATH. The identification of CWD flow tracings "optimal" for analysis could not represent the maximal velocity of transmitral jet, which is a complex three dimensional entity. In addition non-simultaneous determinations of gradient and day-to-day variations in cardiac output may account for discrepancies between CWD and CATH measurements.     

Doppler echocardiographic estimation of cardiac output: analysis of temporal variability

The temporal variability of combined cross-sectional and Dopplerechocardiographic estimates of cardiac output was studied in14 normal subjects. In each subject cross-sectional echocardiographsand Doppler velocities were recorded from the aortic, pulmonaryand mitral valves. Recordings were repeated after 30–60min and after 1–3 months to allow estimation of short-termand long-term temporal variability. A components of variance analysis showed that between-subjectvariability was significantly larger than within-subject variabilityfor all measured and calculated variables. Long-term variabilitywas larger than short-term variability for all variables exceptthe mitral valve area. Calculation of flows from the three measurementsites were equally reproducible and the mean percentage errorfor CO measurements performed 1–3 months apart rangedfrom 6.4% to 7.4%. The 95% confidence intervals for Dopplermeasurements of CO at the three sites ranged from ±0.491min^–1 to ± 0.561 min^–1, suggesting that thetemporal variability of flow measurements using the non-invasiveDoppler method is sufficiently small for the method to be usefulin serial haemodynamic studies.     

Method for computation of cardiac output in mitral stenosis independent of left ventricular dimensions and kinetic state: correlation with cardiac catheterization via the Fick method

An hydraulic orifice formula offering the possibility of quantifying cardiac output in conditions of mitral stenosis is tested using potentially noninvasive portions of catheterization data from patients evaluated for obstructive mitral valve disease. The equation studied is V = (1/21) R A T2, where V is the cardiac output (ml/min), R is the heart frequency, A is the mitral valve area (cm2), and T is the diastolic filling interval (sec/min). The mitral valve area was determined by the Gorlin formula, and R and T were measured from the pressure tracings recorded at cardiac catheterization. The degree of correspondence between the equation tested and the measured cardiac output as determined by the Fick principle technique is characterized by r = 0.87, SE = 450 ml/min, N = 10. The results suggest that the new formulation may offer a noninvasive method for estimating the cardiac output status of patients with mitral valve disease once mitral valve area is measured either at catheterization or by two-dimensional echocardiography.     

Doppler echocardiographic evaluation of Hancock and Bj?rk-Shiley prosthetic values

Doppler echocardiographic characteristics of normally functioning Hancock and Bj?rk-Shiley prostheses in the mitral and aortic positions were studied in 50 patients whose valvular function was considered normal by clinical evaluation. Doppler studies were also performed in 46 patients with suspected malfunction of Hancock and Bj?rk-Shiley valves and who subsequently underwent cardiac catheterization. Mean gradients were estimated for both mitral and aortic valve prostheses and valve area was calculated for the mitral prostheses. Doppler prosthetic mitral valve gradient and valve area showed good correlation with values obtained with cardiac catheterization (r = 0.93 and 0.97, respectively) for both types of prosthetic valves. The correlation coefficient (r = 0.93) for mean prosthetic aortic valve gradient was also good, although Doppler echocardiography overestimated the mean gradient at lower degrees of obstruction. Regurgitation of Hancock and Bj?rk-Shiley prostheses in the mitral and aortic positions was correctly diagnosed. These results suggest that Doppler echocardiography is a reliable method for the characterization of normal and abnormal prosthetic valve function.     

Comparison of cardiac catheterization and Doppler echocardiography in the decision to operate in aortic and mitral valve disease

Clinical decisions utilizing either Doppler echocardiographic or cardiac catheterization data were compared in adult patients with isolated or combined aortic and mitral valve disease. A clinical decision to operate, not operate or remain uncertain was made by experienced cardiologists given either Doppler echocardiographic or cardiac catheterization data. A prospective evaluation was performed on 189 consecutive patients (mean age 67 years) with valvular heart disease who were being considered for surgical treatment on the basis of clinical information. All patients underwent cardiac catheterization and detailed Doppler echocardiographic examination. Three sets of two cardiologist decision makers who did not know patient identity were given clinical information in combination with either Doppler echocardiographic or cardiac catheterization data. The combination of Doppler echocardiographic and clinical data was considered inadequate for clinical decision making in 21% of patients with aortic and 5% of patients with mitral valve disease. The combination of cardiac catheterization and clinical data was considered inadequate in 2% of patients with aortic and 2% of patients with mitral valve disease. Among the remaining patients, the cardiologists using echocardiographic or angiographic data were in agreement on the decision to operate or not operate in 113 (76% overall). When the data were analyzed by specific valve lesion, decisions based on Doppler echocardiography or catheterization were in agreement in 92%, 90%, 83% and 69%, respectively, of patients with aortic regurgitation, mitral stenosis, aortic stenosis and mitral regurgitation. Differences in cardiac output determination, estimation of valvular regurgitation and information concerning coronary anatomy were the main reasons for different clinical management decisions. These results suggest that for most adult patients with aortic or mitral valve disease, alone or in combination, Doppler echocardiographic data enable the clinician to make the same decision reached with catheterization data.     

Effect of percutaneous transvenous mitral commissurotomy for the preservation of sinus rhythm in patients with mitral stenosis

OBJECTIVES: Atrial fibrillation is frequently associated with mitral stenosis and is considered to be an unfavorable factor for the long-term prognosis. The efficacy of percutaneous transvenous mitral commissurotomy(PTMC) was examined for the preservation of sinus rhythm in patients with mitral stenosis after PTMC. METHODS: Long-term clinical data after PTMC were obtained from 71 patients who had undergone PTMC from March 1989 to September 1999. Eighteen patients in sinus rhythm before PTMC were divided into two groups: the SR group(n = 5) who remained in sinus rhythm, and the Af group(n = 13) who showed change from sinus rhythm to persistent or paroxysmal atrial fibrillation after PTMC. RESULTS: Age, sex, mitral valve area(1.4 +/- 0.3 vs 1.2 +/- 0.3 cm2), mean mitral pressure gradient(14.3 +/- 5.5 vs 12.6 +/- 5.9 mmHg), mean left atrial pressure(15.9 +/- 7.6 vs 19.0 +/- 7.7 mmHg), left ventricular end-diastolic pressure(7.5 +/- 2.8 vs 9.3 +/- 3.9 mmHg), left ventricular end-diastolic volume index(77 +/- 13 vs 82 +/- 14 ml/m2), left ventricular ejection fraction(60 +/- 6% vs 55 +/- 4%) and cardiac output(5.1 +/- 0.4 vs 4.9 +/- 0.8 l/m2) before PTMC were not different between the two groups. Changes in mean mitral pressure gradient, mean left atrial pressure and cardiac output immediately after PTMC were not different statistically. Mitral valve area immediately after PTMC was significantly greater in the SR group compared to the Af group(2.3 +/- 0.3 vs 1.8 +/- 0.3 cm2, p < 0.05). The change in mitral valve area was also greater in the SR group(1.0 +/- 0.2 vs 0.6 +/- 0.4 cm2, p < 0.05), but there was no statistical difference in the percentage change of mitral valve area between before and immediately after PTMC(SR group 78 +/- 35% vs Af group 50 +/- 35%). End-diastolic pressure, end-diastolic volume index and ejection fraction immediately after PTMC were not statistically different. CONCLUSIONS: The final mitral valve area immediately after PTMC in the patients with mitral stenosis in sinus rhythm, but not the changes of mean mitral pressure gradient, mean left atrial pressure or cardiac output, is important for the maintenance of sinus rhythm.     

Comparison of Doppler echocardiographic methods of determining cardiac minute volume

In 40 patients without valvular disease, cardiac output was determined by pulsed Doppler echocardiography and thermodilution simultaneously. The sample volume was located in the center of the mitral valve ring, at the tips of the mitral leaflets and in the left ventricular outflow tract, directly proximal to the aortic valve leaflets. Circular cross-sectional areas of the mitral valve ring, aortic ring and bulbus of the aorta were calculated from the M-mode and two dimensional echocardiographic diameters. The mitral orifice was assumed to be an ellipse with varying short axes, determined as the mean diastolic leaflet separation in the M-mode and a constant long axis, derived from the maximal mitral orifice area or mitral ring diameter. Cardiac output was calculated by multiplying time-velocity integrals with different areas and heart rate. Cardiac output, measured by the thermodilution technique, ranged from 4.0 l/min to 10.2 l/min. Cardiac output determined by the different Doppler methods correlated significantly with the thermodilution measurements. Cardiac output measurements in the left ventricular outflow tract provided the best correlation coefficient (0.93) and a standard error of the estimate of 0.589 l/min, when the circular flow area was derived from the M-mode echo of the aortic ring.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reproducibility of Doppler indices of left ventricular systolic and diastolic function in patients with severe chronic heart failure

Doppler ultrasound has been utilized to evaluate cardiac outputand left ventricular filling pressure in patients with variouscardiac diseases. This method would be particularly useful fornon-invasive haemodynamic monitoring in patients with severechronic heart failure. However, few data exist on the reproducibilityof Doppler indices in this population. To determine the magnitudeof technical and biological variability of Doppler indices,serial Doppler echocardiographic studies were performed in 26patients with severe heart failure in the usual clinical setting.Short-term intra- and inter-observer, mid-term and day-to-dayvariabilities of stroke volume, cardiac output, maximal earlyand late diastolic velocities of mitral flow, rate of decreaseand deceleration time of flow velocity in early diastole andthe colour Doppler area of the mitral regurgitant jet were evaluatedby two cardiologists. For each source of variability, correlationcoefficients with standard errors and mean differences betweenpaired determinations with their standard deviations were calculated.Short-term (intra- and inter-observer) variability was smallfor each considered variable: the mean differences of measurementswere within 10% of the mean value for most parameters and nosystematic error was found. Stroke volume and cardiac outputshowed a significant increase in the afternoon. The standarddeviations of differences between day-to-day measurements were41 ml (9% of the mean value) and 39 ml (11% of the mean value),respectively. Doppler indices assessing diastolic filling andcolour Doppler area of mitral regurgitant jet showed greatervariations on a mid-term and day-to-day basis. ‘Spontaneous’shifts from a predominant early diastolic velocity to a predominantlate diastolic velocity mitral flow pattern were observed infour patients with coronary artery disease and less compromisedleft ventricular ejection fraction. We conclude that, in patients with severe heart failure, Dopplermeasurements have a good short-term intra- and inter-observerreproducibility and, therefore, may be suitable for assessingacute interventions. For systolic indices, day-to-day variabilitywas also fairly small, provided that a rigorous—but practicablyobtainable—methodology is used. The relatively large mid-termand day-to-day variability of diastolic variables, observedin less compromised patients, should be considered when serialDoppler studies are performed.     

Pulsed Doppler echocardiographic determination of stroke volume and cardiac output: clinical validation of two new methods using the apical window

Two methods of measuring stroke volume and cardiac output with pulsed Doppler two-dimensional echocardiography were developed and validated against the thermodilution technique in 39 patients, 33 of which were in an intensive care unit. With the use of the apical four-chamber view, a mitral inflow method combined the velocity of left ventricular inflow at the mitral anulus with the cross-sectional area of the anulus calculated from its diameter at middiastole (area = pi r2). From the apical five-chamber view a left ventricular outflow method combined the velocity of left ventricular outflow with the cross-sectional area of the aortic anulus calculated from its diameter during early systole (parasternal long-axis view). Measurements with the mitral inflow and left ventricular outflow methods were obtained in 35 of 39 (90%) and 39 of 39 (100%) patients, respectively. Validation of the mitral method excluded patients with mitral regurgitation (n = 11) and validation of the left ventricular outflow method excluded those with aortic regurgitation (n = 4). Good correlations were observed between thermodilution and Doppler measurements of stroke volume and cardiac output for both the mitral anulus method (R = .96 and .87, respectively) and the left ventricular outflow method (R = .95 and .91, respectively). The results of the two methods correlated well with each other in patients without regurgitant valve lesions. A greater interobserver variability was observed with the mitral anulus method, which was related solely to greater variability in measuring the annular diameter.(ABSTRACT TRUNCATED AT 250 WORDS)     

Noninvasive determination of stroke volume with impulse Doppler echocardiography: comparison with the Fick method

Pulsed Doppler echocardiographic studies were performed in 14 patients (eleven with mitral valve disease, two with coronary artery disease, one with aortic and mitral valve replacement) for determination of cardiac output and the results compared with those obtained from simultaneous measurements carried out according to the Fick principle. Determination of cardiac output and stroke volume was achieved with a pulsed Doppler instrument specifically designed in our laboratory (repetition frequency 10 kHz, maximal penetrance 7.7 cm, ultrasonic beam diameter 3 cm at a distance of 5 cm from the transducer). Doppler measurements of the instantaneous blood flow velocity in the ascending aorta were obtained with the transducer in a suprasternal position. Through integration of the mean spatial velocity over an entire cardiac cycle, the distance traversed by the blood during one heart beat was obtained and then multiplied by the echocardiographically-determined cross-section area of the aorta and the heart rate to yield the cardiac output. There was a statistically-significant linear correlation between the cardiac output determined by Doppler (CO-D) and Fick (CO-F): CO-D = 0.92 CO-F X 0.48, r = 0.85, n = 14. The mean values for the two methods were 3.89 and 3.68 1/min, respectively. The correlation between the two methods improved if only those patients with sinus rhythm were taken into consideration (CO-D = 1.05 CO-F - 0.21, r = 0.93, n = 11). The results show that the pulsed Doppler method used enables accurate determination of cardiac output. The method can be carried out in all patients without aortic stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immediate and midterm outcome of balloon mitral valvotomy in children and adolescents

BACKGROUND: The midterm and long term results of balloon mitral valvotomy (BMV) have not been well characterized, particularly in those below the age of 20 years. AIM: The present study evaluated the hemodynamic benefits, safety and efficacy, as well as the midterm follow-up results, of Inoue BMV in children and adolescents less than 20 years of age who have severe mitral stenosis. PATIENTS: Sixty-one patients younger than 20 years of age underwent BMV between December 1989 and May 1998. METHODS: All patients underwent BMV using the Inoue balloon for symptomatic severe mitral stenosis with a mitral valve area less than 1.2 cm2. Cardiac hemodynamics were acquired before and immediately after BMV. In addition, Doppler echocardiography measurements were obtained during follow-up. RESULTS: The procedure was successful in 59 patients (96.7%). There were no deaths during the procedure or during follow-up. The mean Boston Mitral Echo score was 7.4 1.4. Mitral valve area on cardiac catheterization increased from 0.8 0.3 to 1.9 0.6 cm2 (P<0.001), and the mean mitral valve gradient decreased from 16.9 5 to 5.8 2.8 mmHg (P<0.001). Severe mitral regurgitation developed in one patient (1.6%) and cardiac tamponade developed in two. At a mean follow-up of 36.9 27 months (range 12 to 84 months), mitral valve area by Doppler echocardiography remained at 1.7 0.4 cm2 and the mean mitral valve gradient by Doppler echocardiography was 6 2 mmHg. CONCLUSIONS: BMV is safe and effective in children and adolescent patients with rheumatic mitral stenosis and provides a similar hemodynamic benefit with that reported in adults. The benefits were sustained during a mean follow-up period of 36 months.     

Clinical and hemodynamic results after combined aortic and mitral valve replacement with the Lillehei-Kaster pivoting disc valve.

Combined mitral and aortic valve replacement with the Lillehei-Kaster pivoting disc valve prosthesis was performed in 23 patients. Hospital mortality rate was 8.3 per cent. Detailed postoperative clinical and hemodynamic studies were performed after a mean follow-up period of 24.4 months. Replacement of both valves had resulted in a marked symptomatic and hemodynamic improvement with a normal or nearly normal resting value of cardiac output, pulmonary arterial pressure, and pulmonary vascular resistance while left ventricular end-diastolic pressure (LVEDP) had increased significantly. The rise in left ventricular end-diastolic pressure most probably might be related to the simultaneous rise in cardiac output (Starling mechanism), reflecting the severity and irreversibility of the underlying myocardial disease. Most patients also had systolic gradient across the aortic prosthesis, as well as diastolic gradient across the mitral prosthesis. The gradients across the mitral prosthesis were approximately the same as seen after single valve replacement, while the pressure gradients across the aortic prosthesis were somewhat smaller than previously reported. Angiographic studies of the aortic valve movement indicated that the opening angle of the disc was approximately 60 degrees, and thus less than according to the valve specifications.