Doppler flow characteristics in the assessment of pulmonary artery pressure in ductus arteriosus

The Doppler spectral pattern of flow through the ductus arteriosus was studied in 117 patients. In 37 who underwent catheterisation, Doppler records and aortic and pulmonary artery pressure were available (21 simultaneously with two catheters) for review while the others had surgical ligation of the duct on the basis of the results of non-invasive tests. Four flow patterns were obtained: (a) continuous flow, maximum velocity in late systole with gradual fall throughout diastole; (b) continuous flow, high systolic flow with rapid fall to a very low early diastolic velocity maintained throughout diastole; (c) continuous low velocity, maximum in late diastole; and (d) bidirectional flow. Flow pattern (a) was associated with normal or slightly raised pulmonary artery pressure; (b) with raised pulmonary artery pressure; and (c) and (d) with pulmonary artery pressure at systemic values. Comparison of the Doppler and measured pressure differences between the great arteries was reasonably good for peak values but poor for the trough readings. Doppler ultrasound clearly showed ductal flow; the flow pattern gave an indication of the pulmonary artery pressure, but pressure measurement by application of the Bernoulli equation to the flow velocities cannot yet be regarded as reliable.     

Evaluation of pulmonary arterial pressure by Doppler colour flow mapping in patients with a ductus arteriosus

Blood flow in the pulmonary artery was studied by Doppler colour flow mapping and cardiac catheterisation in 19 patients with a ductus arteriosus and different pulmonary artery pressures. In the four patients with normal pulmonary artery pressures colour Doppler flow mapping showed multicoloured wide and long systolic and diastolic jets in the pulmonary artery. In the 15 patients with raised pulmonary arterial pressure the systolic jets varied from multicoloured to red and were thinner: in patients with considerably raised pulmonary arterial pressure the jets became redder during diastole. The Doppler velocity tracings showed that in patients with normal pulmonary artery pressures the mean peak systolic velocity was higher than the mean end diastolic velocity--so that in all four the ratio of peak systolic velocity to end diastolic velocity was less than 2. The mean peak systolic velocity was much higher than the mean end diastolic velocity in 13 of the 15 patients with raised pulmonary artery pressure; this meant that the ratio of peak systolic velocity to end diastolic velocity was greater than 2 in 10 of 11 patients. The end diastolic velocity was significantly lower in those patients with raised pulmonary artery pressure than in those with normal artery pressure. There was an inverse linear correlation between the mean pulmonary artery pressure and end diastolic ductal jet velocity in 17 of the 19 patients. Colour flow mapping and this quantitative Doppler technique can detect pulmonary artery hypertension in patients with a ductus arteriosus.     

Evaluation of pulmonary arterial pressure by Doppler colour flow mapping in patients with a ductus arteriosus.

Blood flow in the pulmonary artery was studied by Doppler colour flow mapping and cardiac catheterisation in 19 patients with a ductus arteriosus and different pulmonary artery pressures. In the four patients with normal pulmonary artery pressures colour Doppler flow mapping showed multicoloured wide and long systolic and diastolic jets in the pulmonary artery. In the 15 patients with raised pulmonary arterial pressure the systolic jets varied from multicoloured to red and were thinner: in patients with considerably raised pulmonary arterial pressure the jets became redder during diastole. The Doppler velocity tracings showed that in patients with normal pulmonary artery pressures the mean peak systolic velocity was higher than the mean end diastolic velocity--so that in all four the ratio of peak systolic velocity to end diastolic velocity was less than 2. The mean peak systolic velocity was much higher than the mean end diastolic velocity in 13 of the 15 patients with raised pulmonary artery pressure; this meant that the ratio of peak systolic velocity to end diastolic velocity was greater than 2 in 10 of 11 patients. The end diastolic velocity was significantly lower in those patients with raised pulmonary artery pressure than in those with normal artery pressure. There was an inverse linear correlation between the mean pulmonary artery pressure and end diastolic ductal jet velocity in 17 of the 19 patients. Colour flow mapping and this quantitative Doppler technique can detect pulmonary artery hypertension in patients with a ductus arteriosus.     

A Case of Cardiac Amyloidosis Presenting with Mid- to Late Diastolic Retrograde Flow from the Left Atrium to the Pulmonary Vein: Transesophageal Pulsed Doppler Echocardiographic Observations

A patient of cardiac amyloidosis was found to have mid-to late diastolic retrograde flow from the left atrium (LA) to the pulmonary vein. Congo-red staining was positive for amyloid in the rectal tissue. M-mode and two-dimensional echocardiograms revealed symmetric hypertrophy and typical speckled pattern of the left ventricle (LV). The LV pressure curve showed a dip and plateau configuration during diastole, and end-diastolic pressure was 28 mmHg. In addition, the LV pressure was high at mid-diastole, surpassing the pulmonary capillary wedge pressure from mid-to late diastole. The transmitral flow velocity revealed "restrictive" pattern, and the pulmonary venous flow velocity showed retrograde flow from the LA to the pulmonary vein during mid-diastole and atrial systole. It is suggested that recording of the pulmonary venous flow velocity by transesophageal pulsed Doppler echocardiography is useful for understanding the mechanism of the development of pulmonary congestion or edema.     

Pulmonary blood velocity profile variability in open-chest dogs: Influence of acutely altered hemodynamic states on profiles,and influence of profiles on the accuracy of techniques for cardiac output determination

Summary Clinical investigations focused on finding characteristics of noninvasively obtained measurements of pulmonary blood velocity that can be used to quantitate pulmonary blood flow and/or pulmonary pressure have often yielded results whose imprecision has been attributed to flow pattern variability. To determine flow pattern variability in an in vivo animal model in varying hemodynamic states, main pulmonary artery blood velocity waveforms were recorded in 17 dogs at 2-mm intervals along an anterior to posterior wall-oriented axis using a 20-MHz pulsed Doppler needle probe. Control data were obtained before the animals were subjected to altered flow (atrial level shunts) and pressure (10% O₂ inhalation) states. Instantaneous velocity profiles were computed throughout the cardiac cycle. Estimates of pulmonary blood flow were obtained assuming an elliptical model of the pulmonary artery which allowed computation of velocity at all points in the cross section, based on the measured values along the axis. Model-based estimates were compared to measured values and estimates obtained in the traditional fashion, i.e., the product of centerline velocity and cross-sectional area. Results clearly showed marked interanimal variability, even in control states. Reverse flow in the posterior half of the vessel, which tended to become more pronounced with increased pulmonary artery pressure, was observed during late systole and early diastole. Elevated pulmonary blood flow tended to increase the maximum velocities along the anterior wall relative to midline velocities. Neither estimate of cardiac output yielded consistently accurate results (r=0.77 for model-based method,r=0.80 for area times central velocity method). Findings of this study, which highlight the dependency of waveform characteristics on sampling site, the large degree of intersubject variability, and the need for large or multiple sample volumes for pulmonary blood flow determination, help clarify inconsistencies observed by clinicians and suggest that future work with animal models will facilitate a greater understanding of the determinants of human pulmonary velocity waveforms.Work supported in part by: NIH-R01-HL-35389     

Continuous-wave Doppler echocardiographic detection of pulmonary regurgitation and its application to noninvasive estimation of pulmonary artery pressure

Continuous-wave Doppler echocardiography was used to estimate pulmonary artery pressures by measuring pulmonary regurgitant flow velocity in 21 patients with pulmonary hypertension (mean pulmonary artery pressure greater than or equal to 20 mm Hg) and 24 patients without pulmonary hypertension. The pulmonary regurgitant flow velocity patterns, characterized by a rapid rise in flow velocity immediately after closure of the pulmonary valve and a gradual deceleration until the next pulmonary valve opening, were successfully obtained in 18 of the 21 patients with pulmonary hypertension and in 13 of the 24 patients without pulmonary hypertension. As pulmonary artery pressure increased, pulmonary regurgitant flow velocity became higher; the pulmonary artery-to-right ventricular pressure gradient in diastole (PG) was estimated from the pulmonary regurgitant flow velocity (V) by means of the simplified Bernoulli equation (PG = 4V2). The Doppler-determined pressure gradient at end-diastole correlated well with the catheter measurement of the pressure gradient at end-diastole (r = .94, SEE = 3 mm Hg) and with pulmonary artery end-diastolic pressure (r = .92, SEE = 4 mm Hg). The peak of Doppler-determined pressure gradient during diastole correlated well with mean pulmonary artery pressure (r = .92, SEE = 5 mm Hg). Thus continuous-wave Doppler echocardiography was useful for noninvasive estimation of pulmonary artery pressures.     

Responsiveness of raised pulmonary vascular resistance to oxygen assessed by pulsed Doppler echocardiography.

OBJECTIVE--To assess whether changes in Doppler echocardiographic indices in the pulmonary artery correlated with changes in pulmonary vascular resistance. DESIGN--Acceleration time, ejection time, maximal flow velocity, and velocity time integrals were measured at the same time as pressure and oxygen saturation measurements in room air and during 10 minutes of oxygen breathing in the catheterisation laboratory. Pulmonary vascular resistance and pulmonary blood flow (Qp) were calculated from catheterisation data by use of the Fick principle. PATIENTS--14 consecutive patients with a congenital heart defect and a left to right shunt associated with raised pulmonary artery pressure who underwent routine diagnostic cardiac catheterisation to assess their pulmonary vascular resistance. RESULTS--Though pulmonary vascular resistance and systolic pulmonary artery pressure fell significantly during oxygen administration, there was no significant change in the acceleration time or ejection time. Peak velocity increased significantly during oxygen administration. During oxygen breathing Doppler derived measurements of pulmonary flow showed a significant increase in Qp similar to the increase in Qp measured by the Fick principle. There was no significant correlation between the fall in pulmonary vascular resistance and the increase in acceleration time or ejection time, increase in peak velocity, increase in pulmonary artery diameter, or increase in Doppler derived pulmonary blood flow. CONCLUSIONS--Measurements of acceleration and ejection time by Doppler echocardiography did not predict the response of pulmonary artery pressure and resistance to oxygen. Though changes in maximal flow velocity across the pulmonary artery and in Doppler derived pulmonary blood flow measurements became significant during oxygen breathing, the correlation of these changes with fall in pulmonary vascular resistance was poor.     

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.     

Responsiveness of raised pulmonary vascular resistance to oxygen assessed by pulsed Doppler echocardiography.

OBJECTIVE--To assess whether changes in Doppler echocardiographic indices in the pulmonary artery correlated with changes in pulmonary vascular resistance. DESIGN--Acceleration time, ejection time, maximal flow velocity, and velocity time integrals were measured at the same time as pressure and oxygen saturation measurements in room air and during 10 minutes of oxygen breathing in the catheterisation laboratory. Pulmonary vascular resistance and pulmonary blood flow (Qp) were calculated from catheterisation data by use of the Fick principle. PATIENTS--14 consecutive patients with a congenital heart defect and a left to right shunt associated with raised pulmonary artery pressure who underwent routine diagnostic cardiac catheterisation to assess their pulmonary vascular resistance. RESULTS--Though pulmonary vascular resistance and systolic pulmonary artery pressure fell significantly during oxygen administration, there was no significant change in the acceleration time or ejection time. Peak velocity increased significantly during oxygen administration. During oxygen breathing Doppler derived measurements of pulmonary flow showed a significant increase in Qp similar to the increase in Qp measured by the Fick principle. There was no significant correlation between the fall in pulmonary vascular resistance and the increase in acceleration time or ejection time, increase in peak velocity, increase in pulmonary artery diameter, or increase in Doppler derived pulmonary blood flow. CONCLUSIONS--Measurements of acceleration and ejection time by Doppler echocardiography did not predict the response of pulmonary artery pressure and resistance to oxygen. Though changes in maximal flow velocity across the pulmonary artery and in Doppler derived pulmonary blood flow measurements became significant during oxygen breathing, the correlation of these changes with fall in pulmonary vascular resistance was poor.     

Pulsed Doppler flow characteristics of ductus arteriosus in infants with associated congenital anomalies of the heart or great arteries

Pulsed Doppler echocardiography (PDE) from the suprasternal approach was used to assess flow characteristics of ductus arteriosus (DA) in 145 infants (aged 1 day to 6 months) with major congenital heart disease. Direct ductal Doppler interrogation was possible in 138 patients and serial studies before and after medical treatment were performed in 28 infants. According to pulmonary artery pressure and associated heart lesions, 3 ductal shunting patterns were identified. An isolated left-to-right shunt, observed in isolated DA or in right ventricular outflow tract obstruction, was characterized by a continuous flow with a peak velocity in late systole. An isolated right-to-left shunt, observed in persistent fetal circulation and aortic arch abnormalities, was characterized by a continuous flow with a peak velocity in early systole. In patients with a bidirectional ductal shunt, the right-to-left shunt always occurred in systole and the left-to-right shunt began in late systole and extended into diastole. A systolic right-to-left shunt always corresponded to the presence of significant pulmonary hypertension. Ductal flow changes could be documented after prostaglandin E1 therapy in patients with ductus-dependent heart disease or after tolazoline therapy in patients with persistent fetal circulation. Thus, PDE with direct ductal Doppler interrogation is an important complement to the echocardiographic evaluation of DA. It is a safe noninvasive approach to ductal shunt and permits convenient evaluation of the effects of drugs on pulmonary artery resistance (tolazoline) and ductal patency (prostaglandin E1).     

Usefulness of Blalock-Taussig shunt Doppler flow velocity profiles in the assessment of pulmonary artery pressure and flow.

AIM: To assess the utility of continuous wave Doppler evaluation of velocity profiles across a Blalock-Taussig (BT) shunt in the evaluation of pulmonary artery pressure and pulmonary blood flow. METHODS AND RESULTS: Eleven children with complex congenital heart disease with a BT shunt as the sole source of pulmonary blood supply were studied prospectively (median age 5 (0.3-21) months). Doppler evaluations of shunt flow velocity profile and cardiac catheterization were carried out simultaneously. Pulmonary artery pressure and flow were estimated using the modified Bernoulli equation and velocity time integral of shunt flow. There was a positive correlation between (1) the Doppler estimates for mean pulmonary artery pressure, using the diastolic flow velocity, and the mean pulmonary venous wedge pressure ( r = 0.93, SEE = 1.0 mmHG; P<0.001 ) and (2) the Doppler derived and calculated pulmonary blood flow ( r = 0.9, SEE = 0.19 l/min; P<0.001). In contrast, the Doppler estimates for mean pulmonary artery pressure using the peak or mean Doppler gradients were poor. CONCLUSION: The diastolic BT shunt flow velocity can be used reliably to predict mean pulmonary artery pressure when a BT shunt is the sole source of pulmonary artery flow. There was agreement between Doppler predicted pulmonary blood flow and catheter based calculations. These findings may prove a useful tool for perioperative management.     

Doppler techniques in the detection of valvular regurgitation: their value and limitations

To evaluate the clinical value of various Doppler techniques in detecting valvular regurgitation, we compared the sensitivity, timing and duration of regurgitation, and the peak velocity of regurgitant signals among conventional pulsed Doppler, color Doppler, continuous wave Doppler and HPRF Doppler echocardiography. 1. Sensitivity of Doppler techniques in detecting mitral regurgitation: Among fifty patients with mitral regurgitation confirmed by left ventriculography, mitral regurgitation was detected in 48 (96%) using color Doppler and pulsed Doppler echocardiography; in 41 (82%) by HPRF Doppler; and in 37 (74%) by continuous wave Doppler echocardiography. In 103 consecutive normal volunteers, mitral regurgitant signals were detected in 46 (45%) by color Doppler, in 39 (38%) by pulsed Doppler, in 16 (16%) by HPRF Doppler, and in 8 (8%) by continuous wave Doppler echocardiography. 2. Timing and duration of regurgitant signals: To assess the timing and duration of regurgitant signals, 43 patients with regurgitant signals of short duration during systole or diastole were studied using M-mode color Doppler echocardiography. Using the latter method, regurgitant signals throughout systole and the isovolumic relaxation period could be demonstrated in all but four patients who had regurgitant signals of short duration during systole, but suggesting mitral or tricuspid regurgitation. In all patients with regurgitant signals of short duration during diastole, aortic or pulmonary regurgitant signals throughout diastole could be demonstrated with M-mode color Doppler echocardiography. Thus, this technique is superior to conventional pulsed Doppler echocardiography for detecting accurate timing and duration of valvular regurgitation. 3. Peak velocity of regurgitant flow: To compare the peak velocity of regurgitant flow by continuous wave Doppler and by HPRF Doppler echocardiography, 20 patients with mitral regurgitation and 22 patients with tricuspid regurgitation were examined using the both methods. In patients with severe mitral regurgitation, the peak velocity detected by HPRF Doppler echocardiography correlated well (r = 0.96) with that detected by continuous wave Doppler echocardiography. However, in patients with mild mitral regurgitation, the peak velocity detected by HPRF Doppler echocardiography was higher than that detected by continuous wave Doppler echocardiography. In patients with severe tricuspid regurgitation, the peak velocity had a close correlation (r = 0.99) with the both techniques. In patients with mild tricuspid regurgitation, the peak velocity was higher by HPRF than by continuous wave Doppler echocardiography. In conclusion, color or pulsed Doppler echocardiography should be used for detecting valvular regurgitation. M-mode color Doppler echocardiography is superior to conventional pulsed Doppler echocardiography for detecting timing and duration of valvular regurgitation.(ABSTRACT TRUNCATED AT 400 WORDS)     

多普勒组织成像与脉冲多普勒方法对比评价高血压患者舒张功能

目的应用脉冲多普勒组织成像测量二尖瓣环平均舒张速度,以鉴别高血压患者舒张功能假性正常。方法在健康者(正常组200例)与高血压患者(高血压组47例)中,应用脉冲多普勒技术分别测量二尖瓣口舒张早期峰值速度(E)、舒张晚期峰值速度(A),肺静脉收缩波(S)、舒张波(D)及心房收缩波(Ar)。应用脉冲多普勒组织成像测量二尖瓣环各点舒张早期峰值速率(Ea)、舒张晚期峰值速率(Aa)。结果正常组与对照组患者二尖瓣E、A、E/A差异无显著性意义,肺静脉S、S/D、Ar差异有显著性意义,二尖瓣环平均Ea间差异有显著性意义,Aa间差异无显著性意义。结论二尖瓣环舒张早期速率可用于鉴别高血压舒张功能假性正常。     

Diastolic forward blood flow in the pulmonary artery detected by Doppler echocardiography

The etiology of diastolic motion of the pulmonary valve seen on the M-mode echocardiogram has been the subject of much debate. To further investigate diastolic events in the pulmonary artery, the patterns of diastolic pulmonary artery blood flow velocity were studied using pulsed Doppler echocardiography in patients with a normal heart. Two diastolic waveforms were found, one in early diastole related to passive filling of the right ventricle and one in late diastole related to atrial contraction. These waveforms were also related to the two recognized phases of diastolic pulmonary valve motion detected by M-mode echocardiography. The presence of biphasic diastolic blood flow in the pulmonary artery was confirmed by electromagnetic flow velocimetry in four additional patients with various cardiac diseases and normal right heart pressures. It is concluded that both atrial contraction and passive right ventricular filling produce blood flow in the pulmonary artery.     

Diastolic blood flow into the pulmonary artery in carcinoid heart disease

A patient with carcinoid heart disease manifested by mild pulmonary stenosis, severe tricuspid incompetence and mild tricuspid stenosis had unequivocal evidence of blood flow from the right ventricle into the pulmonary artery during ventricular diastole. Simultaneous right ventricular and pulmonary arterial pressure curves demonstrated that right ventricular diastolic pressure exceeded pulmonary arterial pressure during mid-diastole, indicating consistent mid-diastolic opening of the pulmonary valve. This was followed by a parallel increase in right ventricular and pulmonary arterial pressures throughout the rest of diastole. Right heart cineangiograms, obtained with right atrial dye injection, substantiated the pattern of flow from the right ventricle to the pulmonary artery during ventricular diastole. This previously unrecognized phenomenon is probably due to the combined effects of increased right atrial pressure, decreased right ventricular compliance and normal pulmonary arterial pressure.     

Echocardiographic evaluation of left ventricular diastolic function in chronic cor pulmonale

In this study we hoped to understand the abnormalities of left ventricular filling dynamics in chronic cor pulmonale. Our findings showed a severe left ventricular diastolic impairment, directly related to a progressive increase in pulmonary hypertension itself, as expressed by correlation analysis between systolic pulmonary artery pressure and the following parameters: transmitral flow velocity in early/late diastole ratio (r = -0.69, p <0.001), isovolumic relaxation time (r = 0.54, p = 0.001), and transmitral flow velocity in early diastole (r = -0.59, p <0.01).     

Bidirectional ductal shunts in the early neonatal period: evaluation by Doppler color flow imaging

Serial Doppler echocardiographic examinations were performed in 10 normal neonates (0.3-4.0 hrs after birth). The flow patterns through the ductus arteriosus were evaluated using Doppler color flow imaging, pulsed Doppler echocardiography and continuous-wave Doppler echocardiography. At the initial examination, flow through the ductus arteriosus was clearly visualized in all the neonates using Doppler color flow imaging. The ductal flow patterns were categorized as follows: 1. Systolic blue color (right-to-left shunt flow) and diastolic red color (left-to-right shunt flow) in four neonates (group 1). 2. Systolic blue color and diastolic mosaic colors in four neonates (group 2). 3. Continuous mosaic colors in two neonates (group 3). Using pulsed Doppler echocardiography, the systolic right-to-left ductal shunt flow in the groups 1 and 2 was triangular in shape beginning in early systole. The diastolic left-to-right shunt flow was box-like in shape beginning late in systole and lasting long in diastole in the group 1. In the group 2, the diastolic flow showed a wide spectrum (turbulent flow). In the group 3, the flow through the ductus arteriosus had a continuous wide spectrum (turbulent flow). Mosaic or turbulent ductal flow of a left-to-right ductal shunt had high velocities by continuous-wave Doppler echocardiography. Serial examinations revealed that the ductal flow pattern observed in the group 1 changed to the flow pattern observed in the group 2, and then to that of the group 3 with increasing diastolic ductal flow velocities. The estimated aorto-pulmonary pressure gradient according to the simplified Bernoulli equation (delta p = 4V2) using a maximum diastolic left-to-right ductal shunt velocity increased within 12 hrs after birth. It was concluded that bidirectional ductal shunts may be observed in most normal neonates (8/10). With increasing diastolic velocities the bidirectional ductal flows changed to the pattern of a continuous left-to-right shunt. The bidirectional ductal shunt is considered due to physiologic pulmonary hypertension of the newborn and due to less conduction time from the pulmonary valve to the pulmonary end of the ductus than from the aortic valve to the aortic end of the ductus. Analysis of the flow through the ductus provides informations about the neonatal circulatory adaptation, especially in the early neonatal period.     

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.     

Role of echo/Doppler in the diagnosis of pulmonary embolism

Echocardiography supplemented with pulsed and continuous wave Doppler facilities is a potent diagnostic tool in many cardiovascular disorders. Its potential role in the management of patients with suspected pulmonary embolism, though less extensively studied, deserves attention. Benefits of echo/Doppler in these patients are as follows: (1) Echo/Doppler is a noninvasive, relatively inexpensive technique, readily available and repeatable in critically ill patients at the bedside. (2) Echo/Doppler provides a number of independent parameters related to the pulmonary hemodynamics. These parameters include: (a) characteristics of blood flow velocity curves across the right heart valves as well as systolic and diastolic time intervals of the right ventricle (b) motion pattern of the interventricular septum (c) dimensions of the heart chambers and inferior vena cava (d) thickness of the right ventricular free wall (3) Echocardiography allows detection of thrombi within right heart chambers or in major branches of the pulmonary artery in some patients. (4) Echo/Doppler may disclose alternative abnormalities explaining symptoms found in a patient with suspected pulmonary embolism such as pericardial disease, myocardial infarction, aortic dissection, hypovolemic shock, etc.     

Attempts at measuring pulmonary arterial pressure by means of Doppler echocardiography in patients with chronic lung disease

In 72 patients with severe chronic pulmonary or pulmonary vascular disease pulmonary arterial pressure was measured by means of right heart catheterization. Forty three patients had pulmonary hypertension, (32 +/- 11 mmHg) and 27 patients had normal pressure (14 +/- 3 mmHg). These patients were examined with continuous wave (CW) and pulsed wave (PW) Doppler echocardiography. The retrograde systolic tricuspid valve pressure gradient assessed with CW Doppler correlated with systolic pulmonary pressure (r = 0.92, p less than 0.001, SEE 7.7 mmHg) but was measurable in only 17 of the 70 patients. The flow velocity pattern in the right ventricular outflow tract could be recorded in 68 of the 70 patients. Acceleration time (AcT) from systolic flow onset to peak velocity correlated with mean pulmonary artery pressure (r = 0.72, p less than 0.001, SEE 8.3 mmHg). An AcT less than 90 msec had an 84% positive predictive value for pulmonary hypertension. Right ventricular isovolumic relaxation time could be measured in 59 of the 70 patients and correlated with systolic pulmonary artery pressure (r = 0.69, p less than 0.001, SEE 12.4 mmHg). No single Doppler method is at the same time easily applicable and accurate in prediction of pulmonary arterial pressure in patients with chronic lung diseases.