Pulmonary Artery Doppler Research Articles

Transplacental sildenafil rescues lung abnormalities in the rabbit model of diaphragmatic hernia

IntroductionThe management of congenital diaphragmatic hernia (DH) would benefit from an antenatal medical therapy, which addresses both lung hypoplasia and persistent pulmonary hypertension. We aimed at evaluating the pulmonary effects...

Rapid Fire Abstract session: assessing the single ventricule and new techniques for assessing tetralogy477Echocardiographic assessment of ventricular function and predictors of mortality in adults with a Fontan circulation478The left pulmonary artery doppler in the assessment of atrial restriction after the hybrid procedure for hypoplastic left heart syndrome479Magnetic resonance imaging in patients with Fontan physiology detects a high prevalence of liver

Rapid Fire Abstract session: assessing the single ventricule and new techniques for assessing tetralogy477Echocardiographic assessment of ventricular function and predictors of mortality in adults with a Fontan circulation478The left pulmonary artery doppler in the assessment of atrial restriction after the hybrid procedure for hypoplastic left heart syndrome479Magnetic resonance imaging in patients with Fontan physiology detects a high prevalence of liver

Can fetal pulmonary artery Doppler indices predict neonatal respiratory distress syndrome?

To study whether fetal main pulmonary artery (MPA) Doppler indices can predict the development of neonatal respiratory distress syndrome (RDS). This prospective cross-sectional study included pregnant women between 34 and 38+6 weeks gestation. The diagnostic accuracy of MPA Doppler measurements (systolic/diastolic (S/D) ratio, peak systolic velocity (PSV), pulsatility index (PI), resistance index (RI) and acceleration time/ejection time (At/Et)) for diagnosis of neonatal RDS was tested. Of the 698 eligible fetuses, 55 (7.87%) developed neonatal RDS. PSV, PI, RI and At/Et were positively correlated with gestational age. The strongest correlation was found with At/Et (r=0.602, P<0.001). PI and RI were significantly higher, whereas At/Et and PSV were significantly lower in fetuses that developed RDS. A cutoff value of 0.305 for At/Et predicted the development of RDS (sensitivity: 76.4%; specificity: 91.6%). Development of neonatal RDS can be predicted using the MPA At/Et with high sensitivity and specificity.

Pulmonary Impedance and Pulmonary Doppler Trace in the Perioperative Period.

Pulmonary hypertension and associated vascular changes may frequently accompany left-sided heart disease in the adult cardiac surgical population. Perioperative assessment of right ventricular function using echocardiography is well established. In general, understanding the constraints upon which the right ventricle must work is mostly limited to invasive monitoring consisting of pulmonary artery pressures, cardiac output, and pulmonary vascular resistance. The latter 2 measurements assume constant (mean) flows and pressures. The systolic and diastolic pressures offer a limited understanding of the pulsatile constraints, which may become significant in disease. In normal physiology, pressure and flow waves display near-similar contours. When left atrial pressure and pulmonary vascular resistance are increased, changes in pulmonary arterial compliance will result in elevated impedance to right ventricular ejection. Pressure reflections, the result of strong reflectors, return more quickly in a noncompliant system. They augment pulmonary artery pressure causing a premature reduction in flow. As a result, pressure and flow waves will now be dissimilar. The impact of vascular changes on right ventricular ejection can be assessed using pulmonary artery Doppler spectral imaging. The normal flow velocity profile is rounded at its peak. Earlier peaks and premature reductions in flow will make it appear more triangular. In some cases, the flow pattern may appear notched. The measurement of acceleration time, the time from onset to peak flow velocity is an indicator of constraint to ejection; shortened times have been associated with increased pulmonary vascular resistance and pressure. Understanding the changes in the pulmonary arterial system in disease and the physics of the hemodynamic alterations are essential in interpreting pulmonary artery Doppler data. Analyzing pulmonary artery Doppler flow signals may assist in the evaluation of right ventricular function in patients with pulmonary vascular disease.

Predicting Fetal Lung Maturity Using the Fetal Pulmonary Artery Doppler Wave Acceleration/Ejection Time Ratio

Objective: To determine whether the acceleration/ejection time ratio of the fetal main pulmonary artery Doppler waveform (PATET) can accurately predict the results of fetal lung maturity testing in amniotic fluid. Methods: We prospectively studied pregnant women attending our ultrasound unit for clinically indicated fetal lung maturity testing. An ultrasound examination that included measurement of the PATET was performed before the results of the amniocentesis were reported. The results of the PATET and the surfactant/albumin ratio were compared, and a receiver operating characteristic curve was used to determine the PATET cutoff with the optimal sensitivity and specificity for predicting surfactant/albumin ratio results. p < 0.05 was considered statistically significant. Results: Forty-three patients were included in this study. The receiver operating characteristic curve demonstrated that a PATET cutoff of 0.3149 provided a specificity of 93% (95% CI 77-98%), a sensitivity of 73% (95% CI 48-89%), a negative predictive value of 87% (95% CI 70-95%), and a positive predictive value of 85% (95% CI 58-96%) for predicting immature surfactant/albumin ratio results. Conclusion: The PATET may provide a noninvasive means of determining fetal lung maturity with acceptable levels of sensitivity, specificity, and predictive values.

Doppler parameters of fetal lung hypoplasia and impact of sildenafil

Congenital diaphragmatic hernia (CDH) is clinically challenging because of associated lung hypoplasia (LH). There have been no validated parameters to evaluate fetal LH severity. Sildenafil has been shown to improve LH mass in nitrofen-induced pulmonary artery (PA) models, but the pulmonary vascular tone has not been evaluated invivo. The aim of this study was to identify the PA Doppler parameter that best predicts LH severity and to investigate the efficacy of antenatal sildenafil treatment in experimental CDH. Nitrofen (50-60% CDH in offspring) or vehicle on E9.5 and sildenafil or vehicle on E11.5-20.5 were administrated to pregnant rats. On E20.5, PA Doppler indices were investigated with and without maternal hyperoxia. The presence/absence of CDH, lung/body weight ratio and radial saccular count were assessed at E20.5. At baseline, CDH rats had lower PA Doppler acceleration/ejection time ratios and pulsatility index (PI). Maternal hyperoxia resulted ina significant decrease in the PA/PI suggesting pulmonary vasodilation. Incontrast, in CDH fetuses, the ipsilateral PA/PI showed little or no response to hyperoxia (P > .05), and in those with LH, PI response to maternal hyperoxia correlated positively with hernia, lung/body weight ratio (r= 0.70, P= .01). Maternal sildenafil therapy significantly improved PA response to hyperoxia and lung growth in CDH fetuses (P < .01). Pulmonary vasodilation that occurs in E20.5 fetal rats in response to maternal hyperoxia is blunted in CDH. Change in PA/PI with hyperoxia is a useful predictor of LH severity. Sildenafil improves pulmonary vascular response and lung growth in fetal CDH.

Echocardiographic assessment of anomalous origin of the left coronary artery from the pulmonary artery.

Transthoracic echocardiography of a 4-month-old boy with heart failure revealed poor left ventricular contractility with severe mitral regurgitation. Deformation analysis revealed significantly decreased circumferential strain in the anterior and anteroseptal segments. Furthermore, post-systolic shortening was evident in the anterior and lateral segments. The pulmonary arterial short-axis view showed that the left coronary artery originated from the pulmonary artery and color Doppler flow mapping showed retrograde flow in the left coronary artery. These findings were quite helpful for concluding the anomalous origin of the left coronary artery from the pulmonary artery.

Fetal pulmonary and cerebral artery Doppler velocimetry in normal and high risk pregnancy

Studies on fetal lung/brain circulation by means of power Doppler technique have suggested a marked reduction in lung perfusion in high-risk pregnancies as a sign of circulation redistribution. The ratio between lung/brain perfusion might therefore give a new method to predict fetal circulation centralization. The aim of the present study was to obtain fetal lung and cerebral artery ratio in normal and high-risk pregnancies. Doppler samples from proximal right pulmonary artery blood velocities and middle cerebral artery (MCA) were recorded cross-sectionally in 228 normal singleton pregnancies at gestational age 22 to 40 weeks. MCA/right pulmonary artery pulsatility index (PI) ratio was calculated. Doppler samples from proximal right pulmonary artery and MCA were also recorded in 89 high-risk singleton pregnancies and the results related to perinatal outcome. In the normal controls, right pulmonary artery PI remained stable until 30 weeks of gestation with slight increase thereafter until term. The MCA to right pulmonary artery PI ratio increased between 22 and 28 weeks of gestation with the rapid fall towards term. In the high-risk pregnancies group, right pulmonary artery PI showed no significant correlation to perinatal outcome, but signs of brain-sparing in the MCA were correlated to all adverse outcome parameters. Velocimetry of the middle cerebral artery is better than velocimetry of right pulmonary artery in predicting adverse outcome of pregnancy The brain/lung PI ratio does not improve the prediction of adverse outcome of pregnancy.

Can Pulmonary Hypertension and Increased Pulmonary Vascular Resistance Be Ruled in and Ruled Out by Echocardiography?

Several treatment options are available for pulmonary vascular disease, and more patients are considered for right heart catheterization. The aims of this study were to evaluate the diagnostic ability of echocardiography to detect pulmonary hypertension and increased pulmonary vascular resistance (PVR). This retrospective study comprised 118 patients investigated within 48 hours of right heart catheterization. Echocardiography was used to assess pulmonary artery systolic pressure and pulmonary artery mean pressure, filling pressures, cardiac output, and PVR. To diagnose increased PVR, three echocardiographic variables related to pressure reflection in the pulmonary circulation were used. Separate cutoff values aimed at ruling in (high positive likelihood ratio [PLR]) and ruling out (low negative likelihood ratio) pulmonary hypertension (pulmonary artery mean pressure >25 mm Hg) and increased PVR (>3 Wood units) were determined from a derivation group (n= 59, receiver operating characteristic curve analysis) and evaluated in a test group (n= 59). The linear relations between hemodynamic variables assessed with simultaneous echocardiography and right heart catheterization were moderate to strong (R= 0.55 to 0.95), and there were no significant differences, but the limits of agreement were wide. With Doppler pulmonary artery systolic pressure >39mm Hg, the PLR for pulmonary artery mean pressure >25 mm Hg was 4.7, and with Doppler pulmonary artery systolic pressure ≤29 mm Hg, the negative likelihood ratio was 0.12. The PLR for pressure reflection variables with ruling-in cutoff values ranged from 4.3 to 6.4. With all three variables positive, the PLR was 9.9. The negative likelihood ratio with ruling-out cutoff values ranged from 0.22 to 0.08. Echocardiography that includes assessment of pressure reflection in the pulmonary circulation can rule in and rule out pulmonary hypertension and increased PVR.

Acceleration Time-to-Ejection Time Ratio in Fetal Pulmonary Artery Predicts the Development of Neonatal Respiratory Distress Syndrome: A Prospective Cohort Study

This study investigates whether fetal pulmonary artery Doppler waveforms can predict the subsequent development of respiratory distress syndrome (RDS). A prospective cohort study was performed in women with impending preterm birth. Pulsatility index, resistance index, systolic-to-diastolic ratio, peak systolic velocity, and acceleration time-to-ejection time (At/Et) ratio were measured in the main pulmonary artery of fetus just before delivery. Neonates who developed RDS (n = 11) had significantly lower gestational age at birth than those without RDS (n = 31; median: 28.7 [range: 24.7 to 34.9] versus 32.9 [range: 25.7 to 36.0] weeks; p = 0.003); there was no difference in antenatal corticosteroid administration. Pulmonary artery At/Et ratio was significantly higher in fetuses that developed RDS compared with those that did not (median: 0.37 [range: 0.26 to 0.41] versus median: 0.30 [range: 0.21 to 0.44]; p = 0.008). RDS prediction score (=a hundredfold At/Et ratio) is significantly associated with the subsequent development of RDS after controlling for gestational age by logistic regression analysis (odds ratio = 1.31, 95% confidence interval 1.05 to 1.63, p = 0.017). An elevated At/Et ratio in the fetal pulmonary artery is independently associated with the development of RDS in preterm infants. These data suggest that fetal pulmonary artery Doppler velocimetry may provide a reliable noninvasive technique to evaluate fetal lung maturity, similar to the way in which middle cerebral artery Doppler has replaced amniocentesis for the assessment of fetal anemia.

393: A non-invasive method to predict fetal lung maturity using fetal pulmonary artery Doppler wave acceleration/ejection time ratio

393: A non-invasive method to predict fetal lung maturity using fetal pulmonary artery Doppler wave acceleration/ejection time ratio

Determinants of pulmonary hypertension in young adults

Risk factors of pulmonary hypertension (PH) are poorly understood. The objective of this study was to identify the determinants of PH in young adults. We analysed a limited access dataset from the CARDIA (Coronary Artery Risk Development in Young Adults) study provided by the National Heart, Lung and Blood Institute. Pulmonary arterial pressure was assessed by the Doppler pulmonary artery acceleration time (PAAT). Socio-demographic characteristics, self-reported clinical variables, echocardiographic variables, pulmonary function tests, systemic blood pressure and body mass index calculated from height and weight were used in multivariate analysis. There were 4171 study subjects, mean age 24.9 ± 3.6 years, retained in year five with echocardiographic data available after five years of follow-up. The prevalence of severe PH (PAAT ≤ 70 ms) and mild to moderate PH (PAAT = 109.9-70.01 ms) was 1.1% and 14% respectively. Multivariate analysis revealed that body mass index (β = -1.09, p < 0.0001), female gender (β = 6.25, p < 0.0001), age (β = -0.30, p = 0.02), African American race (β = -2.57, p = 0.007), physical activity (β = 0.005, p = 0.002), current smoking (β = -3.42, p = 0.001), left atrial dimension (β = -2.97, p = 0.009) and diastolic dysfunction (β = -13.06, p = 0.006) were statistically significant variables predicting PH. In this large, observational study of young adults, pulmonary hypertension, as assessed by echocardiography, is common. Diastolic dysfunction, obesity, physical inactivity and smoking are associated with elevated pulmonary arterial pressure in young adults.

The Use of Reconstructive Surgery to Improve Quality of Life and Survival in Prenatal Hypoplastic Left Heart Syndrome

Outcomes for hypoplastic left heart syndrome have improved substantially in the era of prenatal diagnosis. Current stage 1 survival rates are in excess of 90% in the absence of risk factors. However, fetuses with an intact atrial septum continue to have poor postnatal survival. Accurate diagnosis of these fetuses with an intact atrial septum relies upon careful assessment of the patent foramen ovale, pulmonary venous Doppler flow patterns and branch pulmonary artery Doppler flow patterns. Prenatal and perinatal interventions, such as the placement of an atrial stent in utero or delivery at a center where a stent may be placed immediately after birth to relieve left atrial hypertension, may improve survival in this particularly high-risk group.

363: A non-invasive method to predict fetal lung maturity using fetal pulmonary artery Doppler wave acceleration time/ejection time ratio

363: A non-invasive method to predict fetal lung maturity using fetal pulmonary artery Doppler wave acceleration time/ejection time ratio

Predictive Value of Doppler Ultrasound in Childhood Pneumonia

This study aimed to determine the predictive value of intercostal and pulmonary artery Doppler flow patterns in the outcome of childhood pneumonia. Pneumonia was classified according to type of pleural effusion and the ultrasound features of consolidations. Doppler flow patterns of intercostal and pulmonary arteries were analysed and correlated with pneumonia type and hospital stay. Of 83 pneumonia cases, 55 were uncomplicated and 28 were complicated. Pleural effusion was present in 54 cases, with 29 non-septated and 25 septated cases. Patients with uncomplicated pneumonia did not have abnormal Doppler flow patterns, compared with 64% (18 of 28) of patients with complicated pneumonia. Doppler ultrasound patterns in childhood pneumonia were correlated with pneumonia type and may be predictive of pneumonia outcome.

Echocardiography Can Identify Patients With Increased Pulmonary Vascular Resistance by Assessing Pressure Reflection in the Pulmonary Circulation

Pulmonary hypertension is a frequent finding in patients with cardiopulmonary disorders. It is important to recognize pulmonary hypertension due to increased pulmonary vascular resistance (PVR), as this affects treatment and prognosis. Patients with increased PVR have an increased pulmonary pressure reflection. We hypothesized that pressure reflection can be described by echocardiography and that variables related to pressure reflection can identify patients with increased PVR. The study comprised 98 patients investigated within 24 hours of right heart catheterization and 20 control subjects. The pressure reflection variables were obtained by pulsed Doppler in the pulmonary artery and continuous Doppler of tricuspid regurgitation. We selected 3 variables related to pressure reflection: the interval from valve opening to peak velocity in the pulmonary artery (AcT, ms), the interval between pulmonary artery peak velocity and peak tricuspid velocity (tPV-PP, ms), and the right ventricular pressure increase after peak velocity in the pulmonary artery (augmented pressure, AP, mm Hg). The correlation between simultaneous catheter- and echocardiography-determined AP was strong (n=19, R=0.83). The AcT, tPV-PP, and AP in patients with a PVR of >3 Woods units (n=71) was (mean+/-SD) 77+/-16 ms, 119+/-36 ms, and 22+/-12 mm Hg, respectively, and differed from patients with a PVR of </=3 Woods units (n=27, P<0.0001), 111+/-32 ms, 39+/-54 ms, and 3+/-4 mm Hg, and from controls, 153+/-32 ms, -19+/-45 ms, and 0 mm Hg, respectively (P<0.0001). The AcT, tPV-PP, and AP values were not correlated with capillary wedge pressure (R=0.08-0.16). The areas under the receiver operator characteristic curve (95%CI) for AcT, tPV-PP, and AP were 0.87 (0.82 to 0.95), 0.94 (0.89 to 0.99), and 0.98 (0.95 to 1.0), respectively. In this study, we describe a novel echocardiography method for assessing pressure reflection in the pulmonary circulation. This method can be used to identify patients with pulmonary hypertension due to increased PVR.

Hemodynamic parameters determined by transesophageal doppler echocardiography and pulmonary artery catheter after volume administration in patients receiving off-pump coronary artery bypass surgery: a correlation analysis

Objective:To investigate the changes of hemodynamic parameters by transesophageal doppler echocardiography(TEE) and pulmonary artery catheter(PCA) before and after volume administration in patients receiving off-pump coronary artery bypass(OPCAB) surgery,to analyze the correlation between the two methods,and to discuss the value of TEE in monitoring the preload during OPCAB.Methods: Twenty patients who were to receive OPCAB were enrolled in the present study.TEE was used to determine the mitral valve flow(MVF).Simultaneously,the central vein pressure(CVP),pulmonary capillary wedge pressure(PCWP),pulmonary artery pressure(PAP),mixed venous oxygen saturation(SvO2),cardiac output(CO),cardiac index(CI),and stroke volume(SV) were examined during OPCAB by PCA.The above parameters were recorded before and immediately after volume infusion(5 ml/kg,in 10 minutes).Patients with SV increased by 10% were taken as effective responders.Pearson correlation analysis was used to examine the relationship of SV with the results of TEE and PAC.Results: There were 14 effective responders after the first volume load,and only 6 after the second infusion.Compared with the baseline values,PCWP of all the patients,and CO,CI and SV of the effective responders increased significantly after volume loading(P0.05);the values of MVe,MTIe,and VTIe+a also increased significantly after volume loading(P0.05);and there were no significant changes in MVa,VTIa,MVedt values after volume loading.The results of correlation analysis of SV with other parameters were: MVe(r=0.36,P0.05),VTImve(r=0.63,P0.05),VTIe/VTIa(r=0.67,P0.01),VTIe+a(r=0.77,P0.01),and PCWP(r=0.35,P0.01).SvO2 was increased after infusion(P0.05).Conclusion: The relationship of TEE parameters with SV is variable.There is a significant positive correlation between SV with VTIe and VTIe+a;and VTI can be used to evaluate the preload of left ventricular,which should be further studied to guide clinical medication.

Doppler Echocardiography Can Provide a Comprehensive Assessment of Right Ventricular Afterload

The purpose of this study was to evaluate novel Doppler echocardiographic methods for a comprehensive assessment of right ventricular afterload, including pulmonary artery (PA) mean pressure (PAMP) and the PA pressure waveform. The study comprised 109 patients who underwent right-heart catheterization simultaneously (group A, n = 31) with Doppler echocardiography on 35 occasions or nonsimultaneously (group B, n = 78) within 24 hours of Doppler echocardiography. Right ventricular afterload variables were obtained using pulsed Doppler in the PA and continuous Doppler of tricuspid regurgitation. The intervals from QRS to the opening and closing of the pulmonary valve and to the peak velocity of tricuspid regurgitation were measured. PA end-diastolic pressure, PA systolic pressure, and PA notch pressure were calculated. The Doppler-derived pressure curve was separated into 3 parts with fitted second-order curves. Catheter PAMP and Doppler PA systolic pressure in group A were strongly related (R = 0.85). The regression equation from group A (PAMP = 0.65 x Doppler PA systolic pressure - 1.2 mm Hg) was used to calculate PAMP in group B. There was no difference between catheter PAMP (mean, 39 +/- 18 mm Hg; range, 8-95 mm Hg) and Doppler PAMP (mean, 39 +/- 15 mm Hg; range, 12-83 mm Hg) (P = .85). The systolic areas under the curves for catheter and Doppler PAMP in group A were 20 +/- 4.7 and 20 +/- 4.0 mm Hg s, respectively (P = .52), and the diastolic areas were 21 +/- 5.7 and 22 +/- 6.3 mm Hg s, respectively (P = .21). A comprehensive assessment of right ventricular afterload that includes PAMP and the PA pressure waveform can be provided by Doppler echocardiography in patients with a wide range of PA pressures and different diagnoses.

Estimation of Pulmonary Vascular Resistance with Doppler Diastolic Gradients

This study was undertaken to determine the diastolic Doppler echocardiographic correlates of pulmonary vascular resistance calculated on cardiac catheterization in patients with secondary pulmonary arterial hypertension. Thirty-eight consecutive patients with congenital heart disease, pulmonary artery hypertension and pulmonary regurgitation were studied. Continuous-wave Doppler-derived pulmonary artery diastolic gradients were measured at 3 points on the pulmonary regurgitant diastolic velocity slope: peak diastolic, end-diastolic (at the R wave on the electrocardiogram), and mid-diastolic (midway between the peak and end-diastolic points). Catheterization data included oximetry, measurements of pressure in the cardiac chambers and great arteries, and calculation of pulmonary vascular resistance index. Doppler-derived peak, mid, and end-diastolic pulmonary regurgitation gradients correlated best with catheterization-measured pulmonary artery systolic, mean and diastolic pressures, respectively. The best Doppler correlate of pulmonary vascular resistance index was the pulmonary artery end-diastolic gradient. Clinically useful information can be obtained from Doppler pulmonary artery diastolic gradients measured on the pulmonary regurgitant diastolic velocity slope, which can estimate the pulmonary arterial pressure as well as pulmonary vascular resistance obtained on cardiac catheterization.

OC273: Prenatal prediction of pulmonary hypoplasia in prolonged oligohydramnios before 26 weeks: clinical, biometric and pulmonary artery Doppler velocimetry correlates

Methods: Included were fetuses with isolated CDH that were liveborn after 30 weeks’ gestation and had postnatal follow-up until discharge from the hospital. Regression analysis was used to investigate the effect on survival of gestation at diagnosis, o/e total FLV, intrathoracic herniation of the liver, side of CDH and gestation at MRI, institution, year and gestational age at delivery. Results: Some 144 fetuses were evaluated between 22 and 38 weeks. Significant predictors of survival (univariate regression analysis) were the presence or absence of intrathoracic herniation of the liver, side of CDH and o/e total FLV. Multiple regression analysis demonstrated that liver herniation and o/e total FLV provided significant independent prediction of survival. Conclusions: In fetuses with isolated CDH, measurement of o/e total FLV and assessment of intrathoracic herniation of the liver by MRI at 22–38 weeks of gestation provide independent prediction of subsequent postnatal survival at discharge from the hospital.