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.     

Determination of pressure gradient across patent ductus arteriosus with simultaneous continuous wave Doppler and catheterization methods and non-invasive estimation of pulmonary artery pressure]

To evaluate the accuracy of Doppler technique for measuring the pressure gradient (delta P) across patent ductus arteriosus (PDA) with a simplified Bernoulli equation (delta P = 4 V2) and estimating the pulmonary artery pressure (PAP) by subtracting delta P from brachial arterial pressure (BAP) measured with cuff sphygmomanometry, Doppler echocardiography and catheterization (both left and right) were performed simultaneously in 20 patients with PDA. For the values of systolic peak delta P (SPPG), mean delta P (MPG) and end-diastolic delta P (EDPG) determined by both Doppler and catheter, the correlation was excellent (r = 0.99, 0.99, 0.99). Doppler determined SPPG also correlated well with catheter determined peak to peak delta P (P-PPG) (r = 0.97). Comparison between Doppler-derived and catheter measured systolic PAP (SPAP), mean PAP (MPAP) and diastolic PAP (DPAP) also showed high correlation (r = 0.95, 0.98, 0.97). This study demonstrates that Doppler echocardiography is valuable for measurement of delta P across PDA and non-invasive estimation of PAP in patients with PDA.     

连续波多普勒和双心导管同步测量动脉导管未闭分流压差的研究

在30例动脉导管未闭患者中,应用连续波多替勒超声心动图和双心导管技术,同步测量了跨动脉导管的分流压差。结果显示:两种技术测量的最大瞬时压差、舒张末期压差和平均压差均高度相关(r分别为0.99,0.96和0.98),三种多普勒压差分别与肺动脉收缩压、舒张压和平均压呈高度负相关(r分别为-0.85、-0.89和-0.90),表明多普勒超声心动图是估测跨动脉导管压差和肺动脉压力的可靠技术。     

Validation of Doppler-derived pulmonary arterial pressure in patients with ductus arteriosus under different hemodynamic states

Twenty-nine patients with a patent ductus arteriosus (PDA) in isolation (n = 17) or in combination with other lesions (n = 12) underwent simultaneous hemodynamic assessment and evaluation of PDA flow velocity by the Doppler method. The accuracy with which Doppler velocity across the PDA predicted pulmonary arterial pressure and the influence of PDA size and shape on the Doppler velocity-pressure relationship were examined. Seventy percent had a cone-shaped PDA (narrowest at the pulmonary artery end), and the remainder were tubular. Narrowest PDA diameter ranged from 1.5 to 9 mm (mean 3.5 mm). Peak systolic and mean pulmonary arterial pressure ranged from 10 to 116 and 8 to 72 mm Hg, respectively. Twenty-one patients (group 1) had left-to-right shunting only. The following variables showed significant correlation in this group: peak instantaneous systolic aortic-to-main pulmonary arterial (MPA) pressure gradient and maximum Doppler velocity across the PDA (slope = 1.03, SEE = 13 mm Hg, r = .94, p less than .001), mean aortic-to-MPA pressure gradient and mean Doppler velocity (slope = 1.06, SEE = 10 mm Hg, r = .95, p less than .001), and end diastolic aortic-to-MPA pressure gradient and minimum Doppler velocity (slope = 1.12, SEE = 8 mm Hg, r = .96, p less than .001). Eight patients (group 2) had bidirectional shunting. In this group peak instantaneous aortic-to-MPA pressure gradient significantly correlated with maximum Doppler velocity measured from the left-to-right shunt (slope = .70, SEE = 2 mm Hg, r = .92, p less than .002) and mean pressure gradient correlated with mean Doppler velocity (slope = .83, SEE = 3 mm Hg, r = .78, p less than .003). Right-to-left Doppler velocities showed no correlation with pressures. In six patients with pulmonary hypertension Doppler velocity changes accurately predicted the effect of pulmonary vasodilation on pulmonary arterial pressure. Doppler velocity of PDA flow reliably predicts pulmonary arterial pressure over a wide range of pressures and PDA shapes and sizes.     

Does the Myocardial Performance Index Affect Pulmonary Artery Pressure in Patients With Mitral Stenosis? A Tissue Doppler Imaging Study

BACKGROUND: The relation between systolic pulmonary artery pressure (PAP) and mitral stenosis (MS) has been poorly understood. Although the mitral valve area (MVA) is an important factor affecting the PAP, there is a wide spectrum of the PAP in patients with MS despite a similar MVA. So, we analyzed whether the left and right ventricular myocardial performance index (MPI) correlated with the PAP. METHODS: Two-dimensional Doppler echocardiography was performed in 46 patients with MS. The left atrial diameter, mean mitral gradient, and MVA were measured. The PAP was derived from the tricuspid regurgitant jet velocity. The ejection time (ET), isovolumetric relaxation time (IRT), and contraction time (ICT) were measured on annulus of interventricular septum, lateral, inferior and anterior wall of left ventricle, and right ventricle free wall from apical two- and four-chamber views in patients with MS and 40 age-matched healthy patients by tissue Doppler imaging (TDI). Then the MPI was calculated as (IRT + ICT)/ET for both left and right ventricle. The correlation of PAP with MVA, mean mitral gradient, left atrial diameter, and left and right ventricular MPI was evaluated. RESULTS: MVA and PAP were measured as 1.57 +/- 0.39 cm2 (0.8-2.5 cm2)and 42 +/- 16 mmHg, respectively. It was determined that the MPI increased in patients with MS(0.59 +/- 0.1 vs 0.48 +/- 0.07, P < 0.001). It was also demonstrated that the MVA, left atrial diameter, mean diastolic gradient, and left ventricular MPI were correlated with PAP(r =-0.39 [P = 0.007], r = 0.43 [P = 0.003], r = 0.58 [P < 0.001], and r = 0.65 [P < 0.001], respectively). In multivariate analysis, although the PAP correlated with mean diastolic gradient and MPI (r = 0.39 [P = 0.013], and r = 0.48 [P < 0.001]), it did not correlate with left atrial diameter and MVA. The PAP also correlated with right ventricular MPI(r = 0.63 [P < 0.001]). CONCLUSION: This study demonstrates that the left ventricular MPI obtained by TDI is an important marker of PAP, and right ventricular MPI correlates with the PAP in patients with MS.     

Validation of Doppler-derived interventricular pressure gradients in patients with ventricular septal defect comparing with catheterization study]

To evaluate the accuracy of Doppler echocardiography for measuring the interventricular pressure gradient in patients with ventricular septal defect (VSD), Doppler echocardiography and dual catheters were performed simultaneously in 31 cases with VSD ranging from 9 to 40 years old. The systolic jet velocities through VSD were recorded by the continuous-wave Doppler technique and converted to the peak instantaneous pressure gradient (delta Pp) and the mean pressure gradient (delta Pm) using a modified Bernoulli's equation with the aid of computer system. Both left and right heart catheters were performed to record the left (LVSP) and the right (RVSP) ventricular systolic pressure simultaneously. Guided by the color flow image Doppler technique, the tip of the right heart catheter was carefully placed within the jet area of the right ventricle. The following parameters were measured from the ventricular pressure curves, the peak instantaneous pressure gradient (IPG), the peak to peak pressure gradient (PPG) and the mean pressure gradient (MPG). The comparison between delta Pp and PPG yielded an excellent correlation (r = 0.99, SEE = 0.69 kPa). There was a close agreement between delta Pp and IPG (r = 0.99, SEE = 0.64 kPa). However, the correlation between delta Pm and MPG was also high (r = 0.98, SEE = 0.67 kPa). We conclude that Doppler echocardiography offers a reliable technique for measuring the interventricular pressure gradient in patients with VSD.     

Noninvasive estimation of systolic pulmonary artery pressure using Doppler echocardiography in patients with chronic obstructive pulmonary disease

In patients with acquired or congenital heart diseases, the systolic pulmonary artery pressure (PAPs) can be predicted using continuous-wave Doppler ultrasound (CWD) measurement of the peak velocity of a tricuspid regurgitation (TR) jet. The aim of this study was to determine whether CWD could be used to accurately estimate PAP in patients with chronic obstructive pulmonary disease (COPD). In 41 patients with stable COPD, we prospectively performed CWD and right heart catheterization. The mean value of PAPs for the entire group was 38.5 +/- 14.9 mm Hg. Pulmonary arterial hypertension (PAPs greater than or equal to 35 mm Hg) occurred in 51 percent (21/41) of patients. Doppler estimation of PAP was impossible in 34 percent (14/41) because of poor signal quality (n = 3), absence of Doppler-detected TR (n = 8), and inadequate TR Doppler signal (n = 3). The PAP could be estimated in 66 percent (27/41) of patients. A statistically significant correlation was found between the Doppler-estimated PAP and the catheter-measured PAPs (r = 0.65; p less than 0.001; SEE = 9 mm Hg). Therefore, CWD appears to be useful for the noninvasive estimation of PAP in patients with COPD. However, this method is associated with two limitations: (1) the high percentage of patients in whom the PAP cannot be estimated by CWD, mainly because of the absence of Doppler-detected TR, and (2) the high value of the standard error of the estimate. The combination of CWD with other Doppler methods should increase the feasibility and accuracy of Doppler echography for the prediction of PAP in patients with COPD.     

Estimation of pulmonary vascular resistance by Doppler echocardiography with simultaneous catheterization

To establish a noninvasive prediction of pulmonary vascular resistance (PVR), we combined continuous wave Doppler pressure gradient with pulsed Doppler volumetric flow methods for measuring mean pulmonary arterial pressure (mPAP) and pulmonary flow (QP) respectively and calculated PVR by the Poiseullie equation. Simultaneous invasive and noninvasive measurements were made beat to beat in 28 patients: 18 patients with patent ductus arteriosus (PDA), 10 with other heart diseases complicated with pulmonary regurgitation (PR). In the PR group, the peak of Doppler determined pressure gradient during diastole correlated well with mPAP measured via catheter, r = 0.99. In the PDA group, the Doppler determined mPAP (subtracts mean pressure gradient across PDA measured by the continuous wave Doppler from brachial artery blood pressure) correlated well with catheter, r = 0.98, Doppler determined QP and PVR also correlated well with catheter, r = 0.98 and 0.99. There were high linear correlations between the mPAP, QP, PVR in all patients by Doppler and catheter, r = 0.99, 0.98, 0.98, respectively. The results indicate that combined continuous wave and pulsed Doppler can predict mPAP, QP, and PVR dynamic indices for PDA and other heart diseases complicated with PR quite accurately.     

Measurement of the right ventricular systolic pressure in ventricular septal defect--a simultaneous correlative study with Doppler echocardiography and dual cardiac catheterization]

To assess the reliability of Doppler echocardiography (DE) in measuring the right ventricular systolic pressure (RVSP) in ventricular septal defect (VSD), both left and right heart catheterization (Cath) and DE were performed simultaneously in 59 cases with VSD. Systolic shunt velocities through VSD were recorded by DE and converted into the peak instantaneous (delta P-PD) and mid-systolic (delta P-MD) pressure gradients using the simplified Bernoulli equation RVSP was estimated by subtracting delta P-PD from the brachial artery systolic pressure (BASP) measured by a cuff sphygmomanometer (method A) and by subtracting delta P-MD from BASP (method B). The left ventricular systolic pressure (LVSP), RVSP, and the peak instantaneous (delta P-PC) and the peak-to-peak (delta P-PP) pressure gradients were measured from pressure c rves. The comparison between BASP and LVSP yielded a good correlation (r = 0.90, SEE = 0.76 kPa). There were also good correlation of interventricular pressure gradients measured by two techniques (r = 0.98, SEE = 0.83-0.93 kPa). Although RVSP estimated by method A correlated well with that measured by Cath, there was a significant underestimation (P < 0.05). On the other hand, RVSP estimated by method B agreed highly with that measured by Cath and there was no significant difference between the two means. We conclude that DE offers a reliable technique for estimating RVSP in VSD noninvasively.     

The pulmonary venous wedge pressure in pulmonary arterial hypertension

The comparability of the main pulmonary artery pressure (PAP) and the pulmonary venous wedge pressure (PVWP) was assessed during cardiac catheterization in 89 patients with pulmonary artery hypertension (PAH) and increased pulmonary blood flow. Preliminary evaluation revealed a wide disparity between the 2 determinations. Fifty-five pull-back pressure recordings from branch-to-main pulmonary artery were analyzed. Twenty-four percent (13/55) had systolic pressure gradients >20 mm Hg. between branch and main pulmonary artery. When PVWP and only ipsilateral branch PAP were compared (n=48), diastolic and mean (m), but not systolic PVWP, correlated closely with branch PAP (r=0.77, r=0.73 and r=0.59, respectively). In 46 of 48 patients the PVWP_m was not significantly greater than the ipsilateral PAP. Twenty-nine of 30 patients with PVWP_m <30 mm Hg. had an ipsilateral PAP_m <40 mm Hg. In 15 patients with PVWP_m between 30 and 39 mm Hg, there was a wide range (30–59 mm Hg) of PAP_m. Three patients with PVWP_m >40 mm Hg. had severe PAH. It is concluded that: 1) hemodynamically significant branch-to-main PAP gradients are present in some patients with PAH and may result in erroneously high pulmonary arteriolar vascular resistance when calculated from main PAP; 2) properly performed PVWP determination can define the lower limit of mean pressure in the ipsilateral branch pulmonary artery; 3) a PVWP_m <30 mm Hg. usually indicates an ipsilateral PAP_m <40 mm Hg; 4) a PVWP_m >30 mm Hg. is compatible with either moderate or severe PAH; 5) correlation of PVWP with PAP is not related to pulmonary blood flow.     

The efficacy of using pulmonary vein wedge pressure for the estimation of pulmonary artery pressure in children with congenital heart disease.

The objectives of this study were to assess the accuracy of pulmonary vein wedge pressure (PVWP) in estimating pulmonary artery pressure (PAP) in various types of congenital heart disease, including single-ventricle physiology. The systolic, diastolic, and mean values of both PAPs and PVWPs were measured in 30 patients (a total of 46 points). Pulmonary artery pressure ranged from 13 to 74 (34 +/- 15) mm Hg in systole, 5 to 25 (13 +/- 6) mm Hg in diastole, and 6 to 48 (18 +/- 10) mm Hg in mean. As a whole, good correlations between PAPs and PVWPs were observed (systole, r = 0.70; diastole, r = 0.85; mean, r = 0.82; P < 0.0001). However, with an increase in PAP, the discrepancy between PAPs and PVWPs increased. When the mean PVWP was more than 18 mm Hg, the mean PVWP in 14 of 24 (58%) underestimated the mean PAP by up to 22 mm Hg (mean difference, -1.7 +/- 5.8 mm Hg). On the other hand, all of the patients with mean PVWPs less than 18 mm Hg (n = 22) had mean PAPs less than 18 mm Hg (r = 0.86; PAP = 1.11 x PVWP - 1.41; P < 0.0001), and the mean difference was -0.2 +/- 1.8 mm Hg. The mean PVWP can accurately estimate the mean PAP in children with congenital heart disease who have a mean PVWP less than 18 mm Hg.     

Relationship of pulmonary artery diastolic and pulmonary artery wedge pressures in mitral stenosis

Resting and exercise hemodynamic studies were performed in 33 patients with mitral stenosis (14 men and 19 women; average age, 25 years) in normal sinus rhythm with normal pulmonary vascular resistances. A normal pulmonary vascular resistance was assumed when the resting pressure gradient between the pulmonary artery diastolic and mean pulmonary artery wedge pressures was 5 mm. Hg or less. A satisfactory correlation existed between the pulmonary artery wedge and pulmonary artery diastolic pressures at rest (r = 0.9017) and during exercise (r = 0.8670). A method of predicting pulmonary artery wedge pressure from pulmonary artery diastolic pressure during exercise was formulated. The correlation between the predicted and measured exercise pulmonary artery wedge pressures was very close (r = 0.9561). It is suggested that during exercise the pulmonary artery diastolic pressure can be modified as above and substituted for mean pulmonary artery wedge pressure if the resting gradient between pulmonary artery wedge and pulmonary artery diastolic pressure is known.     

Estimation of systolic pulmonary artery pressure with continuous wave Doppler pressure gradient method: a simultaneous Doppler and catheter correlative study

To estimate more precisely the systolic pulmonary artery pressure (PASP), continuous wave Doppler pressure gradient method and catheter measurement were performed simultaneously in 85 patients. There were 30 patients with tricuspid regurgitation (TR), 35 with ventricular septal defect (VSD), and 20 with patent ductus arterosus (PDA). For maximal transtricuspid pressure gradient (TRPG) determined by continuous wave Doppler and catheter determined PASP in TR group, the correlation coefficient (r) was as high as 0.99. For Doppler determined PASP (subtracting pressure gradient across PDA from systemic arterial pressure measured by cuff sphygmomanometer) and catheter determined PASP in PDA group, r was 0.95. Doppler determined PASP in VSD group (subtracting pressure gradient across VSD from systemic arterial pressure) also correlated well with catheter determined PASP (r = 0.97). This study demonstrates that continuous wave Doppler pressure gradient method can accurately estimate PASP in patients with TR, PDA, and VSD.     

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.     

Estimation of mean left atrial pressure from transesophageal pulsed Doppler echocardiography of pulmonary venous flow

To determine whether pulmonary venous flow and mitral inflow measured by transesophageal pulsed Doppler echocardiography can be used to estimate mean left atrial pressure (LAP), we prospectively studied 47 consecutive patients undergoing cardiovascular surgery. We correlated Doppler variables of pulmonary venous flow and mitral inflow with simultaneously obtained mean LAP and changes in pressure measured by left atrial or pulmonary artery catheters. Among the pulmonary venous flow variables, the systolic fraction (i.e., the systolic velocity-time integral expressed as a fraction of the sum of systolic and early diastolic velocity-time integrals) correlated most strongly with mean LAP (r = -0.88). Of the mitral inflow variables, the ratio of peak early diastolic to peak late diastolic mitral flow velocity correlated most strongly with mean LAP (r = 0.43), but this correlation was not as strong as that with the systolic fraction of pulmonary venous flow. Similarly, changes in the systolic fraction correlated more strongly with changes in mean LAP (r = -0.78) than did changes in the ratio of peak early diastolic to peak late diastolic mitral inflow velocity (r = 0.68). We conclude that in the surgical setting observed, pulmonary venous flow from transesophageal pulsed Doppler echocardiography can be used to estimate mean LAP. This technique may provide a rapid, simple, and relatively noninvasive means of gauging this variable in patients undergoing intraoperative transesophageal echocardiography.     

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.     

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.     

Influence of right ventricular pressure overload on left and right ventricular filling in cor pulmonale assessed with Doppler echocardiography

We evaluated the influence of right ventricular (RV) pressure overload on RV and left ventricular (LV) filling using Doppler echocardiography in cor pulmonale. The LV and RV inflow signals were recorded by Doppler flowmetry. The end-diastolic (ED) and end-systolic (ES) LV short axis images were detected by 2-dimensional echocardiography in 20 healthy subjects and in 36 cases of chronic pulmonary disease (CPD) with pulmonary hypertension. We measured (1) the ratio of the peak velocity of inflow due to atrial contraction to the peak velocity of rapid inflow (A/R), (2) the deceleration half-time of rapid inflow (delta TD), (3) the corrected radius of curvature (cRC) of the interventricular septum (IVS) at ES and ED, and (4) the percent change of length of 16 radial grids (%CL) using the fixed method on the ED and ES short axis images. In 17 of 36 patients with CPD, we measured the systolic pulmonary artery pressure (sPAP), the cardiac index (CI), the mean pulmonary capillary wedge pressure (mPCWP), the end-diastolic right ventricular pressure and the partial oxygen pressure of arterial blood (PaO2). The results were as follows: in CPD, (1) both the RV and the LV diastolic behavior were impaired as shown by increased A/R (1.04 +/- 0.20, 0.98 +/- 0.17, respectively) and prolonged delta TD (115 +/- 20, 100 +/- 17 msec, respectively), (2) the IVS was flattened at ED (cRC of IVS = 0.67 +/- 0.12), (3) the IVS wall motion was impaired (%CL of IVS = 133 +/- 13), (4) the sPAP had an adequate correlation with RV A/R (r = 0.80, p less than 0.01), RV delta TD (r = 0.59, p less than 0.05), LV A/R (r = 0.82, p less than 0.01), LV delta TD (r = 0.61, p less than 0.05), cRC of IVS (r = 0.67, p less than 0.01), %CL of IVS (r = -0.59, p less than 0.05). There was no significant correlation between the LV diastolic behavior and the CI, the mPCWP, the PaO2. It is concluded that the impairment of RV diastolic behavior was caused by the decreased RV compliance due to RV free wall hypertrophy. Moreover, the RV pressure overload interfered with the IVS motion during diastole, this regional impairment of diastolic behavior of the IVS subsequently causing impairment of LV diastolic filling.     

Reduced pulmonary clearance of endothelin in congestive heart failure: a marker of secondary pulmonary hypertension

BACKGROUND: Endothelin-1 (ET-1) levels are elevated in congestive heart failure (CHF) in relation with the severity of pulmonary hypertension. We evaluated whether a reduced pulmonary ET-1 clearance could contribute to this elevation. METHODS AND RESULTS: We determined pulmonary ET-1 clearance in 24 patients with CHF in relation with hemodynamics, plasma ET-1, and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. Pulmonary ET-1 extraction, measured by the single bolus indicator-dilution technique, was reduced to 32 +/- 14% in comparison to historic controls (47 +/- 7%). Plasma ET-1 clearance by the lungs (924 +/- 588 mL/min) was also much lower than in controls (1424 +/- 79 mL/min). Clearance correlated inversely with mean pulmonary artery pressure (PAP, r = -.47, P = .017) and pulmonary capillary wedge pressure (r = -.47, P = .017) and positively with the rate of left ventricular (LV) relaxation LV -dP/dt (r = .593, P = .004). After multivariate analysis, only mean PAP and LV -dP/dt were independently correlated with ET-1 clearance (r = -.40, P = .03, and r = .55, P = .005, respectively). Plasma ET-1 levels did not correlate with clearance (r = .038, P = .86), and there was no significant arteriovenous ET-1 gradient. There was a mild nonsignificant correlation between plasma ET-1 and pulmonary artery systolic pressure (r = .38, P = .06), but a strong correlation with right atrial pressure (r = .696, P < .0001) and NT-proBNP levels (r = .51, P = .001), which were maintained after multivariate linear regression (r = .60, P = .001, and r = .32, P = .04, respectively). CONCLUSION: Pulmonary ET-1 clearance is reduced in CHF in relation with the severity of pulmonary hypertension. This reduced clearance does not significantly modulate plasma ET-1 levels. Whether this is only a marker of secondary pulmonary hypertension or could modulate pulmonary vascular tone will require further studies.     

Pulmonary artery pulse pressure and wave reflection in chronic pulmonary thromboembolism and primary pulmonary hypertension

OBJECTIVES: The purpose of this time-domain study was to compare pulmonary artery (PA) pulse pressure and wave reflection in chronic pulmonary thromboembolism (CPTE) and primary pulmonary hypertension (PPH). BACKGROUND: Pulmonary artery pressure waveform analysis provides a simple and accurate estimation of right ventricular afterload in the time-domain. Chronic pulmonary thromboembolism and PPH are both responsible for severe pulmonary hypertension. Chronic pulmonary thromboembolism and PPH predominantly involve proximal and distal arteries, respectively, and may lead to differences in PA pressure waveform. METHODS: High-fidelity PA pressure was recorded in 14 patients (7 men/7 women, 46 +/- 14 years) with CPTE (n = 7) and PPH (n = 7). We measured thermodilution cardiac output, mean PA pressure (MPAP), PA pulse pressure (PAPP = systolic - diastolic PAP) and normalized PAPP (nPAPP = PPAP/MPAP). Wave reflection was quantified by measuring Ti, that is, the time between pressure upstroke and the systolic inflection point (Pi), deltaP, that is, the systolic PAP minus Pi difference, and the augmentation index (deltaP/PPAP). RESULTS: At baseline, CPTE and PPH had similar cardiac index (2.4 +/- 0.4 vs. 2.5 +/- 0.5 l/min/m2), mean PAP (59 +/- 9 vs. 59 +/- 10 mm Hg), PPAP (57 +/- 13 vs. 53 +/- 13 mm Hg) and nPPAP (0.97 +/- 0.16 vs. 0.89 +/- 0.13). Chronic pulmonary thromboembolism had shorter Ti (90 +/- 17 vs. 126 +/- 16 ms, p < 0.01) and higher deltaP/PPAP (0.26 +/- 0.01 vs. 0.09 +/- 0.07, p < 0.01). CONCLUSIONS: Our study indicated that: 1) CPTE and PPH with severe pulmonary hypertension had similar PA pulse pressure, and 2) wave reflection is elevated in both groups, and CPTE had increased and anticipated wave reflection as compared with PPH, thus suggesting differences in the pulsatile component of right ventricular afterload.