Noninvasive determination of pulmonary arterial systolic pressure by continuous wave Doppler

We evaluated the accuracy of continuous wave Doppler for estimating pulmonary arterial systolic pressure in patients with tricuspid regurgitation. Of 44 patients with a variety of cardiac disorders, 39 (89%) had Doppler-detected tricuspid regurgitation. Adequate spectral profiles of the flow signals were obtained in 34 of them (87%), representing 77% of the entire group. Continuous wave Doppler ultrasound was used to measure the maximum velocity of the regurgitant jet, and by applying the modified Bernoulli equation, the systolic pressure gradient between the right ventricle and the right atrium was calculated. Pulmonary arterial systolic pressure was estimated by adding the transtricuspid gradient to the mean right atrial pressure, and correlated well with catheterization values (r = 0.96). The correlation coefficient was not significantly modified if mean right atrial pressures were excluded in the calculations (r = 0.91). Continuous wave Doppler constitutes a sensitive method for the detection of tricuspid regurgitation. The method using the tricuspid gradient provides an accurate estimation of pulmonary arterial systolic pressure. Combined with other available methods (pulsed wave Doppler), this noninvasive technique can yield information comparable with that obtained at catheterization.     

Quantitative assessment of pulmonary hypertension in patients with tricuspid regurgitation using continuous wave Doppler ultrasound

Doppler ultrasound examination was performed in 69 patients with a variety of cardiopulmonary disorders who were undergoing bedside right heart catheterization. Patients were classified into two groups on the basis of hemodynamic findings. Group I consisted of 20 patients whose pulmonary artery systolic pressure was less than 35 mm Hg and Group II consisted of 49 patients whose pulmonary artery systolic pressure was 35 mm Hg or greater. Tricuspid regurgitation was detected by Doppler ultrasound in 2 of 20 Group I patients and 39 of 49 Group II patients (p less than 0.001). Twenty-six of 27 patients with pulmonary artery systolic pressure greater than 50 mm Hg had Doppler evidence of tricuspid regurgitation. In patients with tricuspid regurgitation, continuous wave Doppler ultrasound was used to measure the velocity of the regurgitant jet, and by applying the Bernoulli equation, the peak pressure gradient between the right ventricle and right atrium was calculated. There was a close correlation between the Doppler gradient and the pulmonary artery systolic pressure measured by cardiac catheterization (r = 0.97, standard error of the estimate = 4.9 mm Hg). Estimating the right atrial pressure clinically and adding it to the Doppler-determined right ventricular to right atrial pressure gradient was not necessary to achieve accurate results. These findings indicate that tricuspid regurgitation can be identified by Doppler ultrasound in a large proportion of patients with pulmonary hypertension, especially when the pulmonary artery pressure exceeds 50 mm Hg. Calculation of the right ventricular to right atrial pressure gradient in these patients provides an accurate noninvasive estimate of pulmonary artery systolic pressure.     

Continuous wave Doppler determination of right ventricular pressure: a simultaneous Doppler-catheterization study in 127 patients

Simultaneous continuous wave Doppler echocardiography and right-sided cardiac pressure measurements were performed during cardiac catheterization in 127 patients. Tricuspid regurgitation was detected by the Doppler method in 117 patients and was of adequate quality to analyze in 111 patients. Maximal systolic pressure gradient between the right ventricle and right atrium was 11 to 136 mm Hg (mean 53 +/- 29) and simultaneously measured Doppler gradient was 9 to 127 mm Hg (mean 49 +/- 26); for these two measurements, r = 0.96 and SEE = 7 mm Hg. Right ventricular systolic pressure was estimated by three methods from the Doppler gradient. These were 1) Doppler gradient + mean jugular venous pressure; 2) using a regression equation derived from the first 63 patients (Group 1); and 3) Doppler gradient + 10. These methods were tested on the remaining 48 patients with Doppler-analyzable tricuspid regurgitation (Group 2). The correlation between Doppler-estimated and catheter-measured right ventricular systolic pressure was similar using all three methods; however, the regression equation produced a significantly better estimate (p less than 0.05). Use of continuous wave Doppler blood flow velocity of tricuspid regurgitation permitted determination of the systolic pressure gradient across the tricuspid valve and the right ventricular systolic pressure. This noninvasive technique yielded information comparable with that obtained at catheterization. Approximately 80% of patients with increased and 57% with normal right ventricular pressure had analyzable Doppler tricuspid regurgitant velocities that could be used to accurately predict right ventricular systolic pressure.     

Quantitative assessment of pulmonary hypertension in patients with rheumatic heart disease using continuous wave Doppler ultrasound

The accuracy of Doppler ultrasound in estimating pulmonary arterial systolic pressure non-invasively was evaluated in 50 patients with rheumatic heart disease. In all cases, the maximal velocity of the tricuspid regurgitation jet was measured by continuous wave Doppler ultrasound and the systolic pressure gradient between right ventricle and the right atrium was calculated by the modified Bernoulli equation. There was a close correlation between Doppler estimated and hemodynamically measured transtricuspid systolic gradient (r = 0.86, P less than 0.001). Right ventricular systolic pressure, which equals pulmonary arterial systolic pressure in the absence of right ventricular outflow obstruction, was calculated by adding a constant of 10 to the Doppler gradient and also by using a regression equation. Right ventricular systolic pressure obtained by both of these Doppler methods correlated closely with values at cardiac catheterization (r = 0.82 and 0.83, respectively). Our study suggests that pulmonary arterial systolic pressure can be determined non-invasively with accuracy, by Doppler ultrasound, in patients with rheumatic heart disease.     

Feasibility of generating hemodynamic pressure curves from noninvasive Doppler echocardiographic signals

Objectives. This study was designed to determine the feasibility of Doppler generation of accurate, complete right ventricular and pulmonary artery pressure curves in patients with Dopplermeasurable tricuspid and pulmonary regurgitation.Background. Doppler-derived flow velocities have been used to assess right ventricular systolic pressure; pulmonary artery systolic, diastolic and mean pressures, and left ventricular systolic and diastolic pressures. Instantaneous gradient across any area of discrete narrowing is accurately derived using the simplified Bernoulli equation (4V²). Invasive catheterization is currently the only means of generating intracardiac pressure curves. Noninvasively derived pressure curves using Doppler echocardiography would be a considerable advance in the assessment of normal and pathologic cardiac hemodynamics.Methods. Right ventricular and pulmonary artery pressure curves were generated in 18 of 22 patients with measurable tricuspid and pulmonary valve regurgitation using superimposition of Doppler-measured tricuspid and pulmonary valve blood flow velocities on an assumed right atrial pressure. Dopplermeasured right ventricular and pulmonary artery pressure curves were compared with simultaneous catheterization-measured curves.Results. Doppler-derived pulmonary artery systolic pressure (Doppler PAP) correlated with simultaneous catheter-measured pulmonary artery pressure (Cath PAP) by the equation Doppler PAP = 0.92(Cath PAP) + 4.5, r = 0.98. Other Doppler-derived pressure measurements that correlated at near identity with the catheterization-measured corresponding measurement include Doppler-derived pulmonary artery mean pressure (Doppler mean PAP) [Doppler mean PAP = 0.85(Cath mean PAP) + 2.6, r = 0.97], and Doppler-derived right ventricular pressure (Doppler RVP) [Doppler RVP = 0.84(Cath measured RVP) + 7.9, r = 0.98]. Doppler-derived pulmonary artery diastolic pressure (Doppler PAP diast) did not correspond as well in this study [Doppler PAP diast = 0.45(Cath PAP diast) + 6.6, r = 0.83].Conclusions. Clinically usable right ventricular and pulmonary artery pressure curves can be derived by superimposing Dopplermeasured tricuspid and pulmonary valve blood flow velocities in patients with tricuspid and pulmonary valve regurgitation.     

Quantification of left-side intracardiac pressures and gradients using mitral and aortic regurgitant velocities by simultaneous left and right catheterization and continuous-wave doppler echocardiography

Noninvasive determination of left-side intracardiac pressures is of clinical importance in many cardiac diseases. To test the reliability and accuracy of left-side intracardiac pressure measurements by continuous-wave Doppler echocardiography, using left-side valvular regurgitations, 47 patients with mitral regurgitation, with or without associated aortic regurgitation, underwent simultaneous Doppler and left and right catheterization. Doppler-derived left atrial and ventricular end-diastolic pressures were respectively estimated by subtracting mitral regurgitant gradient from systolic blood pressure and by diastolic blood pressure minus aortic regurgitant gradient. There were high correlations of mitral (r = 0.961) and aortic regurgitant gradients (r = 0.896) and of left atrial (r = 0.945) and ventricular end-diastolic pressures (r=0.854) between noninvasive and invasive measurements. Also, agreement analyses showed that there was close agreement between the two technical measurements for each parameter. The present study concluded that continuous-wave Doppler echocardiography provides a reliable and accurate method for the noninvasive evaluation of left-side intracardiac pressures and gradients in patients with mitral and aortic regurgitations.     

Noninvasive estimation of both systolic and diastolic pulmonary artery pressure from Doppler analysis of tricuspid regurgitant velocity spectrum in patients with chronic heart failure

Background Noninvasive estimation of pulmonary artery systolic and diastolic pressures usually requires the investigation of both tricuspid and pulmonary regurgitant jets and an estimate of right atrial pressure. A new, noninvasive method to obtain pulmonary diastolic pressure (based on the hemodynamic demonstration that right ventricular systolic pressure and pulmonary artery diastolic pressure are equal at the time of pulmonary valve opening) from the analysis of tricuspid regurgitation alone has been described in a small cohort of patients. We sought to verify the accuracy of this method in a large population of patients with heart failure. Methods An estimate of pulmonary artery diastolic pressure was obtained by transposing the pulmonary opening time (from the onset of the R wave on the electrocardiographic tracing to the beginning of pulmonic forward flow on Doppler examination) onto the tricuspid regurgitant velocity curve and calculating the pulmonary artery diastolic pressure value as the pressure gradient between the right ventricle and right atrium at this time. The study group included 86 consecutive patients (64 men, aged 52 ± 11 years) with heart failure (New York Heart Association class ≥II, 94%) who were in stable clinical condition with a chiefly idiopathic (57%), ischemic (24%), or other form (13%) of dilated cardiomyopathy. Noninvasive, right-sided pressures were compared with invasive measurements obtained during right heart catheterization performed within 24 hours. The Bland and Altman graphic method was used together with the calculation of the Lin concordance correlation coefficient and its 95% CI to assess the agreement between hemodynamic and echocardiographic measurements. Results Catheter-derived pulmonary artery systolic pressure ranged from 8 to 119 mm Hg (mean 42 ± 21 mm Hg), pulmonary artery diastolic pressure from 1 to 59 mm Hg (mean 20 ± 11 mm Hg), and right atrial pressure from −5 to 20 mm Hg (mean 6 ± 5 mm Hg). Tricuspid regurgitation was detected in 75 of 86 patients (87%). Pulmonary artery systolic pressure ranged from 13 to 110 mm Hg (mean 44 ± 21 mm Hg); the pressure gradient between the right ventricle and right atrium at time t of the pulmonary valve opening on the tricuspid regurgitation velocity curve was measurable in 70 of 75 (93%) cases and ranged from 3.5 to 64 mm Hg (mean 22 ± 11 mm Hg). Good agreement was observed not only for pulmonary artery systolic pressure but also for pulmonary artery diastolic pressure, based on the analysis of the tricuspid regurgitation velocity jet, with a slight difference between measurements (−1.8 and 0.1, respectively), no evident pattern of point scattering, and a high concordance correlation coefficient that was elicited by the virtually total overlapping of lines on the graph. Overall results were not significantly different whether patients with depressed right ventricular function (right ventricular ejection fraction ≤35%), with a tricuspid regurgitation grade ≥2 and atrial fibrillation were included in the analysis. Conclusions The narrow paired difference for the estimate of pulmonary artery systolic pressure and the even better difference for pulmonary artery diastolic pressure using the tricuspid regurgitation velocity curve analysis indicates that this new method reliably estimates invasive right-sided pressures over a wide range of pressure values in patients with heart failure. The overall good correlation with invasive values indicates that Doppler examination of tricuspid regurgitation alone may provide a simple and comprehensive new method for the noninvasive evaluation of right ventricular and pulmonary hemodynamics in patients with heart failure. (Am Heart J 2002;144:1087-94.)     

Quantitative analysis of systolic function of the right ventricule by Doppler echocardiography

The recording of the velocity of tricuspid valve regurgitation by continuous wave Doppler enables the calculation of the instantaneous systolic pressure gradient between the right ventricle and right atrium. As right atrial pressure is relatively constant, the rate of acceleration of the regurgitant jet reflects the quality of the rise in pressure in the right ventricle in early diastole, and therefore right ventricular contractility. The authors studied 3 Doppler parameters of the rate of velocity increase of the tricuspid regurgitation; the maximum rate of acceleration (dV/dt max), the maximum derivative of the pressure (dP/dt max) and the mean rate of increase in pressure (T). The interobserver variability of these indices is low (r greater than 0.96); reproducibility is good in patients with sinus rhythm but mediocre in atrial fibrillation. The comparison of the Doppler indices with the right ventricular isotopic fraction in 26 patients with tricuspid regurgitation showed a good correlation (dV/dt max, r = 0.79, p less than 0.0001; dP/dt max, r = 0.69, p less than 0.0001; T, r = 0.60, p = 0.0012). These results show that right ventricular systolic function can be evaluated by continuous wave cardiac Doppler by recording the spectral envelope of tricuspid regurgitation.     

Noninvasive estimation of pulmonary artery diastolic pressure in patients with tricuspid regurgitation by Doppler echocardiography.

OBJECTIVES: The purpose of this study was to determine whether Doppler echocardiographic assessment of right ventricular pressure at the time of pulmonary valve opening could predict pulmonary artery diastolic pressure. BACKGROUND: Doppler echocardiography has been used to estimate right ventricular systolic pressure noninvasively. Because right ventricular and pulmonary artery diastolic pressure are equal at the time of pulmonary valve opening, Doppler echocardiographic estimation of right ventricular pressure at this point might provide an estimate of pulmonary artery diastolic pressure. METHODS: We studied 31 patients who underwent right heart catheterization and had tricuspid regurgitation. Pulmonary flow velocity was recorded by pulsed wave Doppler echocardiography, and tricuspid regurgitant velocity was recorded by continuous wave Doppler echocardiography. The time of pulmonary valve opening was determined as the onset of systolic flow in the pulmonary artery. Tricuspid velocity at the time of pulmonary valve opening was measured by superimposing the interval between the onset of the QRS complex on the ECG and the onset of pulmonary flow on the tricuspid regurgitant envelope. The tricuspid gradient at this instant was calculated from the measured tricuspid velocity using the Bernoulli equation. This gradient was compared to the pulmonary artery diastolic pressure obtained by right heart catheterization. MEASUREMENTS AND RESULTS: The pressure gradient between the right atrium and right ventricle obtained at the time of pulmonary valve opening ranged from 9 to 31 mm Hg (mean, 19+/-5) and correlated closely with invasively measured pulmonary artery diastolic pressure (range, 9 to 36 mm Hg; mean, 21+/-7 mm Hg; r = 0.92; SEE, 1.9 mm Hg). CONCLUSION: Doppler echocardiographic measurement of right ventricular pressure at the time of pulmonary valve opening is a reliable noninvasive method for estimating pulmonary diastolic pressure.     

Tricuspid Regurgitation and Right Heart Dimensions at Early and Late Follow-Up After Orthotopic Cardiac Transplantation

Tricuspid regurgitation is common immediately after cardiac transplantation, but its course over long-term follow-up is not known. This study was performed to determine the prevalence of valvular regurgitation and to evaluate if pulmonary hypertension or right ventricular enlargement were associated with the severity of tricuspid regurgitation at early and late follow-up after cardiac transplantation. Fifty-five patients had hemodynamic and echocardiographic studies performed at 1 week and 2.4 ± 1.3 years after cardiac transplantation. Right ventricular dimensions were measured and related to the severity of tricuspid regurgitation as assessed by Doppler color flow. There was a fall in right heart filling pressures with decreases in the systolic pulmonary artery pressure (31 mmHg ± 7 mmHg vs 27 mmHg ± 7 mmHg, P = 0.0001) and right atrial pressure (8 ± 5 mmHg vs 6 ± 4 mmHg, P < 0.01). Sixty-three percent of patients had mild or higher grade tricuspid regurgitation initially and 71% at follow-up (P = NS). The major determinant of tricuspid regurgitation severity at late follow-up was the presence of flail tricuspid leaflets (P < 0.0001). There was an association between the change in grade of tricuspid regurgitation and the change in right ventricular diastolic area (P = 0.002) and the change in tricuspid annulus diameter (P < 0.0001). The prevalence of tricuspid regurgitation remains high at late follow-up after cardiac transplantation and neither pulmonary hypertension nor right ventricular dilatation are prerequisites for tricuspid regurgitation, which can persist in their absence. Flail tricuspid leaflets are the most important predictors of the severity of tricuspid regurgitation following cardiac transplantation.     

The importance of tricuspid valve structure and function in the surgical treatment of rheumatic mitral and aortic disease.

A significant proportion of individuals with rheumatic disease have tricuspid valve involvement which may be clinically important and alter the medical or surgical approach to treatment. Therefore 50 patients with rheumatic left-sided valvular lesions who were referred for operative treatment were studied. Thirty patients had angiographically significant tricuspid regurgitation (group I) and 20 had a competent tricuspid valve (group II). Pre-operative cardiac assessment included Doppler echocardiography and contrast ventriculography. Patients with tricuspid regurgitation more commonly had mitral valve disease or combined mitral and aortic valve lesions, (P less than 0.001) and were more likely to have atrial fibrillation than those without tricuspid regurgitation (P less than 0.001). Pulmonary arterial systolic and mean right atrial pressures were higher in group I (both P less than 0.01). A close relationship was found between the angiographic and Doppler assessment of the degree of tricuspid regurgitation (P less than 0.01). Doppler-derived measurement of the right ventricular-right atrial systolic pressure difference correlated well with the systolic trans-tricuspid pressure difference measured at cardiac catheterization (y = 0.7x + 22, r = 0.67, P less than 0.001) and the pulmonary arterial systolic pressure (y = 0.8x + 27, r = 0.71, P less than 0.001). Rheumatic involvement of the tricuspid valve identified by pre-operative echocardiography was confirmed in five patients at surgery. Of the 13 patients with functional tricuspid regurgitation at operation, only two had been diagnosed as having organic disease by echocardiography. Furthermore, in all 18 cases where Doppler suggested grade 3 or 4+ tricuspid regurgitation, surgical repair or replacement of the valve was performed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgical experience with diseases of the tricuspid valve. Cross-sectional and Doppler echocardiographic evaluation following DeVega's repair

Seventy-eight patients undergoing mitral valve surgery with or without replacement of the aortic valve also underwent procedures on the tricuspid valve over a period of 10 years. All patients were in functional class III or IV preoperatively. The procedures were performed in all patients with organic disease of the tricuspid valve (N = 44) and in those with moderate or severe functional tricuspid valvar regurgitation (N = 34). Seventy-one patients underwent DeVega's annuloplasty with or without commissurotomy. The overall mortality was 11.5%. 65 long-term survivors were followed up for a period of 6 months to 10 years (mean 5.3 years). Sixty-three patients were in functional class I or II at the last follow-up. Six patients had clinical evidence of mild to moderate tricuspid regurgitation. Regression of cardiomegaly (as judged by the chest radiograph and right ventricular hypertrophy seen in the electrocardiogram) was evident in most cases. Fifty-one of 54 patients evaluated by cross-sectional echocardiography were reported to have a functionally normal tricuspid valve. Doppler echocardiography in 28 patients showed no significant tricuspid regurgitation or stenosis in 26 patients. Eleven consecutive patients undergoing DeVega's annuloplasty were studied prospectively with pre- and postoperative Doppler echocardiography. Good correlation existed between right ventricular systolic pressures predicted by Doppler with those obtained preoperatively at cardiac catheterization. Postoperative Doppler echocardiography in these 11 patients showed complete restoration of competence of the tricuspid valve as well as normalisation of the right ventricular systolic pressure in 10 patients.     

Doppler echocardiographic evaluation of pulmonary artery pressure in chronic obstructive pulmonary disease. A European multicentre study. Working Group on Noninvasive Evaluation of Pulmonary Artery Pressure. European Office of the World Health Organization, Copenhagen

The feasibility, reproducibility and reliability of Doppler echocardiography in evaluation of pulmonary artery pressure in patients with chronic obstructive pulmonary disease (COPD) were determined in a multicentre study. In 100 COPD patients with mean pulmonary artery pressure ranging from 10 to 62 mmHg at cardiac catheterization, pulmonary pressure estimation was attempted by four Doppler echocardiographic methods. These methods comprised the calculation of transtricuspid and transpulmonary pressure gradients from Doppler-detected tricuspid or pulmonary regurgitation, the evaluation of right ventricular outflow tract velocity profiles with the measurement of right ventricular systolic time intervals and the measurement of the right ventricular isovolumic relaxation time. In 98 (98%) patients at least one of the methods could be employed. A tricuspid regurgitation jet was detected in 47 (47%) patients but its quality was adequate for measurement in 30 (30%). Pulmonary regurgitation jet velocity was measured only in five cases. The standard error of estimate in testing intra- and interobserver reproducibility of Doppler systolic time intervals was less than 5%. The predictive value of right ventricular outflow tract acceleration time less than 90 ms in the identification of patients with mean pulmonary artery pressure greater than 20 mmHg was 80%. Of Doppler echocardiographic data, best correlations with mean pulmonary artery pressure were found for the transtricupid gradient (r = 0.73, SEE = 7.4 mmHg), for the right ventricular acceleration time (r = 0.65, SEE = 8 mmHg) and right ventricular isovolumic relaxation time (r = 0.61, SEE = 8.5 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Measurement of right ventricular dP/dt. A simultaneous/comparative hemodynamic and Doppler echocardiographic study]

Right ventricular systolic function is difficult to assess by Doppler echocardiography. We studied 14 patients with tricuspid regurgitation on Doppler echocardiographic examination with the object of determining an index of right ventricular contractility based on the continuous Doppler signal of the regurgitant jet. The rate of increase in right ventricular pressure was calculated between 2 points, V1 and V2, situated on the ascending limb of the velocity profile of the tricuspid regurgitation and compared with the dP/dt max measured simultaneously at right heart catheterisation. The different values of V1 and V2 were: 0 and 1 m/s, 0 and 2 m/s, 0.5 and 1.5 m/s, 1 and 2 m/s and 0.5 and 2 m/s. An excellent correlation was observed between the catheter dP/dt max and the rate of increase in pressure measured by Doppler between 0 and 2 m/s (r = 0.93; p = 0.0001) and between 0.5 and 2 m/s (r = 0.93; p = 0.0001). The correlation was not as close between 0 and 1 m/s (r = 0.69; p = 0.048) and there was no correlation with the measurements between 0.5 and 1.5 m/s and between 1 and 2 m/s. Doppler echocardiography could therefore be used for non-invasive assessment of right ventricular systolic function in clinical practice.     

The value of recording the pulmonary insufficiency flow by continuous Doppler for the evaluation of systolic pulmonary artery pressure

Systolic, diastolic and mean pulmonary artery pressures can be evaluated by Doppler recordings of the maximal velocity of tricuspid regurgitation and early and late diastolic pulmonary regurgitant flow. The aim of this study was to assess the reliability of the calculation of systolic pulmonary artery pressure from pulmonary regurgitant flow by comparing the values with those obtained from the tricuspid regurgitant flow in the same patient. With this objective in mind, we investigated 70 patients with an average age of 45 +/- 34 years, in sinus rhythm, all of whom had tricuspid and pulmonary regurgitant jets which could be recorded with continuous wave Doppler. Systolic pulmonary artery pressure was calculated as follows: from tricuspid regurgitation: maximum pressure gradient + 10 mmHg; from pulmonary regurgitation: 3 x early diastolic gradient - 2 x late diastolic gradient + 10 mmHg. The systolic pulmonary artery pressures calculated from tricuspid and pulmonary regurgitation were: 42 +/- 16 mmHg and 43 +/- 17 mmHg respectively (r = 0.97) with an estimated standard error of 4.7 mmHg. These results show that the recording of pulmonary regurgitation by continuous wave Doppler allows accurate estimation of pulmonary artery pressures. The calculation by the two methods using tricuspid and pulmonary regurgitant jets increases the reliability of the results and provides a means of internal validation of the Doppler technique.     

Simultaneous measurement of left atrial pressure by Doppler echocardiography and catheterization.

Simultaneous, continuous wave Doppler echocardiography, left ventricular systolic and mean pulmonary capillary wedge pressure measurements were performed during cardiac catheterization in 54 patients with mitral regurgitation. Doppler-derived left atrial pressure, which was calculated by subtracting mitral regurgitant gradient from brachial artery systolic pressure, correlated well with mean pulmonary capillary wedge pressure by catheter (r = 0.933, SEE = 2.9 mmHg, P < 0.001); a comparison between non-invasive and invasive systolic gradients across the mitral valve yielded a high correlation (r = 0.91, SEE = 6.0 mmHg, P < 0.001); and there was also a high correlation between brachial artery and left ventricular systolic pressures (r = 0.93, SEE = 4.9 mmHg, P < 0.01). It is concluded that Doppler echocardiography provides a reliable and accurate method for complete non-invasive assessment of left atrial pressure in patients with mitral regurgitation.     

Pulsed doppler echocardiographic detection of right-sided valve regurgitation: Experimental results and clinical significance

Pulsed Doppler echocardiography may allow noninvasive detection of tricuspid insufficiency as disturbed or turbulent systolic flow in the right atrium and pulmonary insufficiency as turbulent diastolic flow in the right ventricular outflow tract. Accordingly, six open chest mongrel dogs were examined with Doppler echocardiography before and after surgical creation of tricuspid and pulmonary insufficiency. The Doppler technique detected the appropriate lesion in all instances, with a specificity of 100 percent.In 121 patients (20 without heart disease, 101 with heart disease of various causes), pulsed Doppler echocardiography was used to detect right-sided valve regurgitation. Results were compared with right-sided pressure measurements and M mode echocardiographic findings in all, and with right ventricular angiography in 21 patients. Pulsed Doppler study detected tricuspid insufficiency in 61 of 100 patients, 12 (20 percent) of whom had clinical evidence of this lesion. Angiographic evidence of tricuspid regurgitation was present in 18 patients, 17 of whom had positive Doppler findings (sensitivity 94 percent), and absent in 3, all with negative Doppler findings. Pulmonary insufficiency was found on pulsed Doppler study in 47 of 91 patients, 3 of whom (all after pulmonary valvotomy) had clinical evidence of this lesion. Increased right ventricular systolic pressure (greater than 35 mm Hg) was noted more often in patients with (55 of 61 or 90 percent) than in those without (22 of 59 or 37 percent) tricuspid insufficiency (p <0.01). Pulmonary arterial mean pressure was elevated (22 mm Hg or less) more often in patients with (38 of 43 or 88 percent) than in those without (24 of 64 or 38 percent) pulmonary insufficiency (p <0.01).Thus, pulsed Doppler echocardiography appears to be an accurate noninvasive technique for detection of right-sided valve regurgitation. The absence of diagnostic physical findings in many of the patients indicates that the hemodynamic severity of the Doppler-detected valve insufficiency was probably insignificant. However, because of its high incidence rate (87 percent) and association with pulmonary hypertension (87 percent), pulsed Doppler detection of tricuspid or pulmonary insufficiency, or both (in the absence of pulmonary stenosis) was found superior to M mode echocardiographic measurements (right ventricular size, pulmonary valve motion) in the prediction of pulmonary hypertension.     

Noninvasive estimation of right ventricular systolic pressure in ventricular septal defect by a continuous wave Doppler technique

Noninvasive determination of right ventricular systolic pressure was attempted in 27 patients with ventricular septal defect based on the peak velocity of left-to-right shunt flow as measured in the right ventricle by a continuous wave Doppler technique. The systolic pressure gradient between the ventricles (delta p: mmHg) was calculated according to the simplified Bernoulli's formula, delta p = 4 V2, where V (m/sec) is the peak velocity of the left-to-right shunt flow. Right ventricular systolic pressure was determined by subtracting delta p from the systolic blood pressure measured in the upper arm, which was regarded as the left ventricular systolic pressure. The peak velocity of left-to-right shunt flow could be measured in all patients except one with muscular ventricular septal defect, and values ranged from 0.6 to 4.8 m/sec. The peak velocity of left-to-right shunt flow decreased inversely with the increase in right ventricular systolic pressure. The values of right ventricular systolic pressure determined by the continuous wave Doppler technique correlated highly (r = 0.820) with those determined by cardiac catheterization. The peak velocity of left-to-right shunt flow also showed high negative correlations with the pulmonary to systemic pressure ratio (r = -0.876) and pulmonary to systemic resistance ratio (r = -0.855). These results indicate that the continuous wave Doppler technique is clinically useful for determination of right ventricular systolic pressure as well as the pulmonary to systemic pressure ratio and pulmonary to systemic resistance ratio.     

Comparison of Doppler derived haemodynamic variables and simultaneous high fidelity pressure measurements in severe pulmonary hypertension.

OBJECTIVE--To assess relations between right ventricular pressure measured with a high fidelity transducer tipped catheter and the characteristics of tricuspid regurgitation recorded with Doppler echocardiography. DESIGN--A prospective non-randomised study of patients with severe pulmonary hypertension referred for consideration of lung transplantation. SETTING--A tertiary referral centre for cardiac and pulmonary disease, with facilities for invasive and non-invasive investigation, and assessment for heart and heart-lung transplantation. PATIENTS--10 patients with severe pulmonary hypertension being considered for lung transplantation. ENDPOINTS--Peak right ventricular, pulmonary artery, and right atrial pressures; peak positive and negative right ventricular dP/dt; peak Doppler right ventricular-right atrial pressure drop; Doppler derived peak positive and negative right ventricular dP/dt; and time intervals of Q to peak right ventricular pressure and to peak positive and negative right ventricular dP/dt. RESULTS--The mean (SD) pulmonary artery systolic pressure was 109 (29) mm Hg. The peak Doppler right ventricular-right atrial pressure drop underestimated peak right ventricular pressure by 38 (21) mm Hg, and by 21 (18) mm Hg when the Doppler value was added to the measured right atrial pressure (P values < 0.05). This discrepancy was greater for higher pulmonary artery pressures. The timing of peak right ventricular pressure differed, with the Doppler value consistently shorter (mean difference 16 ms, P < 0.05). Values of peak positive and negative right ventricular dP/dt and the time intervals Q-peak positive right ventricular dP/dt and pulmonary closure to the end of the pressure pulse differed between the two techniques in individual patients, but not in a consistent or predictable way. CONCLUSIONS--Doppler echocardiography significantly underestimates the peak right ventricular pressure and the time interval to peak right ventricular pressure in pulmonary hypertension, particularly when severe. These differences may be related to orifice geometry. Digitisation of Doppler records of tricuspid regurgitation provides useful semiquantitative estimates of absolute values and timing of peak positive and negative right ventricular dP/dt. Clinically significant differences may exist, however, and must be considered in individual patients.     

Noninvasive measurement of the time constant of left ventricular relaxation using the continuous-wave Doppler velocity profile of mitral regurgitation.

BACKGROUND. The time constant of isovolumic relaxation (tau) is an important parameter of ventricular diastolic function, but the need for invasive measurement with high-fidelity catheters has limited its use in general clinical cardiology. The Doppler mitral regurgitant velocity spectrum can be used to estimate left ventricular (LV) pressure throughout systole and may provide a new noninvasive method for estimating tau. METHODS AND RESULTS. Mitral regurgitation was produced in nine dogs, and ventricular relaxation was adjusted pharmacologically and with hypothermia. High-fidelity ventricular pressures were recorded, and tau was calculated from these hemodynamic data (tau H) assuming a zero-pressure asymptote. Continuous-wave mitral regurgitant velocity profiles were obtained, and the ventriculo-atrial (VA) pressure gradient was calculated by the simplified Bernoulli equation; tau was calculated from the Doppler data from the time of maximal negative dP/dt until LV-LA pressure crossover. Three methods were used to correct the Doppler VA gradient to better approximate the LV pressure before calculating tau: 1) adding actual LA V wave pressure (to yield tau LA); 2) adding 10 mm Hg (tau 10); and 3) no adjustment at all (actual VA gradient used to calculate tau 0). The agreement between tau H and the three Doppler estimates of tau was assessed by linear regression and by the mean and standard deviation of the error between the measurements (delta tau). the measurements (delta tau). tau H ranged from 29 to 135 msec. Without correction for LA pressure, the Doppler estimate of tau seriously underestimated tau H: tau 0 = 0.30 tau H + 9.4, r = 0.79, delta tau = -35 +/- 18 msec. This error was almost completely eliminated by adding actual LA pressure to the VA pressure gradient: tau LA = 0.92 tau H + 7.6, r = 0.95, delta tau = 2 +/- 7 msec. Addition of a fixed LA pressure estimate of 10 mm Hg to the VA gradient yielded an estimate that was almost as good: tau 10 = 0.89 tau H + 4.9, r = 0.88, delta tau = -2 +/- 12 msec. In general, tau was overestimated when actual LA pressure was below this assumed value, and vice versa. Numerical analysis demonstrated that assuming LA pressure to be 10 mm Hg should yield estimates of tau accurate to +/- 15% between true LA pressures of 5 and 20 mm Hg. CONCLUSIONS. This study demonstrates that the Doppler mitral regurgitant velocity profile can be used to provide a direct and noninvasive measurement of tau. Because mitral regurgitation is very common in cardiac patients, this method may allow more routine assessment of tau in clinical and research settings, leading to a better understanding of the role of impaired ventricular relaxation in diastolic dysfunction and the effect of therapeutic interventions.