Aortic flow patterns in normal neonates with patent ductus arteriosus: evaluation by Doppler color flow imaging

Serial Doppler echocardiography was performed in 12 normal neonates (0.5-4.0 hrs after birth) to evaluate flow patterns through the ductus arteriosus, and in the aorta and brachiocephalic artery. At the initial examination, flow through the ductus arteriosus was bidirectional in eight of the 12 neonates and continuously left-to-right in the remaining four. The bidirectional ductal shunts became continuous left-to-right flows within 11-21 hrs after birth in seven of the eight neonates and resolved by 29-47 hrs after birth. In the remaining four neonates, the continuous left-to-right shunts disappeared 14-36 hrs after birth. Systolic ejection flow patterns in the aorta and brachiocephalic artery had a triangular shape with the peak velocity in early systole, followed by a minimal flow reversal in all sites examined. Diastolic flow patterns in each arterial site were as follows: 1. In the ascending aorta, there was slow and sustained diastolic forward flow, which did not change with increasing age. 2. In the brachiocephalic artery, there was a pan-diastolic flow reversal in the neonates with bidirectional ductal flow (7/8). This pattern changed to slow pan-diastolic forward flow when the ductal changed to continuous left-to-right flow or when the ductal closure was confirmed. Most (3/4) of the remaining four neonates with continuous left-to-right ductal flow exhibited pan-diastolic forward flow. Another showed a pan-diastolic flow reversal 2 hrs after birth, which changed to pan-diastolic forward flow in the second examination 6 hrs after birth. 3. In the distal aortic arch, there was a pan-diastolic forward flow in all the neonates, and the velocity decreased when a closure of the ductus was confirmed. 4. In the descending aorta, there was a pan-diastolic flow reversal in neonates with bidirectional ductal flow (7/8). This reversal changed to pan-diastolic forward flow, when the ductal flow changed to continuous left-to-right flow or when the ductal closure was confirmed. In the remaining four neonates with continuous left-to-right ductal flow, two showed a pan-diastolic flow reversal at the initial examinations 2 to 3 hrs after birth. This became a pan-diastolic forward flow at the second examinations 6 and 12 hrs after birth. In the other two, there was a pan-diastolic forward flow which did not change. This pan-diastolic flow reversal observed in the brachiocephalic artery and descending aorta was closely related to the bidirectional ductal flow.(ABSTRACT TRUNCATED AT 400 WORDS)     

Noninvasive Doppler echocardiographic evaluation of shunt flow dynamics of the ductus arteriosus

The pulsed Doppler technique was used to record the flow velocity patterns in the ductus arteriosus and the pulmonary artery in 26 patients with either isolated or complicated patent ductus arteriosus (PDA). In all patients, abnormal Doppler signals indicating left-to-right (L-R) or right-to-left shunt flow or both could be obtained at the site of the ductus arteriosus. These Doppler flow patterns determined within the ductus coincided with the direction of ductal flow seen on the contrast two-dimensional echocardiogram. No Doppler signals of shunt flow were demonstrated in any of 42 control subjects. The peak, mean, and diastolic velocities of the L-R shunt flow within the ductus were measured from the ductal flow velocity profiles. With the Doppler-derived measurements of the mean and diastolic velocities, patients with normal pulmonary arterial pressure and those with evidence of pulmonary hypertension could be correctly identified. In addition, the mean velocity of the diastolic antegrade flow portion obtained from the proximal left pulmonary artery, which was related to ductal L-R shunting, was measured in 16 patients with isolated PDA. This Doppler flow determinant showed a good linear correlation with the L-R shunt ratio determined by Fick's method (r = .88, p less than .01). Our technique permits the noninvasive evaluation of shunt flow dynamics in patients with PDA.     

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).     

Real-time bidimensional-color Doppler evaluation of patent ductus arteriosus

In order to assess the presence and severity of left-to-right shunt at ductal level, eleven patients with proven ductus arteriosus (PDA), ages 1 day to 16 years, were examined by real-time two-dimensional Doppler echocardiography. Eighteen subjects with no signs of cardiovascular disease were selected as normal controls. Normal pulmonary flow pattern was clearly visualized in the healthy subjects examined. The jet stream through the ductus was well imaged in the main pulmonary artery in patients with PDA and disappeared in two infants after pharmacologic manipulation with indomethacin. The colour-coded shunt area was related to the left-to-right shunt calculated at cardiac catheterization. Moreover, the combined use of colour-flow Doppler and continuous-wave Doppler yielded a reliable noninvasive assessment of pulmonary artery pressure.     

Doppler echocardiographic flow characteristics of isolated patent ductus arteriosus: better delineation by Doppler color flow mapping

Eighteen infants and children with isolated ductus arteriosus and various hemodynamic states were examined with the Doppler color flow mapping technique to study the flow patterns of the patent ductus and its adjacent structures. Direct visualization of the ductus was achieved in all patients. All ductal flow was shunting left to right from the descending aorta to the pulmonary artery even in the presence of significant elevation of pulmonary artery pressure. However, transient bidirectional shunting was observed in two patients on serial studies. Disturbed systolic and diastolic flows were demonstrated within the ductus in each case. The blood flows in the main pulmonary artery consisted of three distinguishable areas: 1) a characteristic high velocity turbulent retrograde ductal jet throughout the entire cardiac cycle, located in the anterolateral aspect of the main pulmonary artery; 2) nonspecific low velocity retrograde late systolic and early diastolic flow, located in the posteromedial aspect of the main pulmonary artery; and 3) low velocity forward systolic and diastolic flow, occupying the remaining area of the pulmonary artery. The blood flows in the descending aorta near the ductal orifice consisted of disturbed systolic and diastolic flows in a reversed direction. By providing detailed real time blood flow information with simultaneous imaging of the ductus, Doppler color flow mapping greatly facilitates the detection of a small ductal shunt. This technique also allows detection of a bidirectional or right to left ductal shunt.     

Left-to-right shunt via the foramen ovale in the early neonatal period: evaluation by Doppler color flow mapping

Serial two-dimensional Doppler echocardiography was performed in 22 normal neonates (2-9 hours after birth). A left-to-right shunt through the foramen ovale and a shunt through the ductus arteriosus were evaluated. Interatrial shunts were observed as transseptal jets in 16 of 22 neonates on initial examination and resolved nine to 26 hours after birth in 13 neonates. In the remaining three neonates the shunts were observed more than six days and resolved by two months of age. Shunts through the ductus arteriosus were observed in all neonates examined as diastolic or continuous flows toward the transducer in the main pulmonary artery at the initial examination. The ductal flow resolved simultaneously with (3/13) or after (10/13) the disappearance of interatrial flow. With two-dimensional echocardiography, the enlarged left atrium and rightward deviation of the interatrial septum were observed in the neonates with interatrial shunts. This was confirmed by the immobile septum primum and the increased ratio of the left atrial to aortic diameters (LA/Ao ratio) on the M-mode echo. The interatrial septum became mobile and the LA/Ao ratio decreased after disappearance of the interatrial shunts. It was speculated that in neonates with large ductal shunts, large pulmonary venous flow enters into the less compliant left ventricle and raises the left ventricular end-diastolic pressure. Then, increased left atrial pressure distends the interatrial septum and causes left-to-right interatrial shunts via the stretched foramen ovale. This shunt is considered one of the physiological phenomena occurring in the early neonatal period.     

Real-time Doppler color flow mapping for detection of patent ductus arteriosus

In this study, ultrasound Doppler color flow mapping systems were utilized to examine flow in the pulmonary artery in 31 premature and term infants (aged 4 hours to 9 months) with patent ductus arteriosus accompanying respiratory distress syndrome, as an isolated lesion, or with patent ductus in association with other cyanotic or acyanotic congenital heart disorders. The flow mapping patterns were compared with those of a control population of 15 infants who did not have patent ductus arteriosus. In unconstricted ductus arteriosus, the flow from the aorta into the pulmonary artery was detected in late systole and early diastole and was distributed along the superior leftward lateral wall of the main pulmonary artery from the origin of the left pulmonary artery back in a proximal direction toward the pulmonary valve. In constricted patent ductus arteriosus, or especially in a ductus in association with cyanotic heart disease, the position of the ductal shunt in the pulmonary artery was more variable, often directed centrally or medially. Waveform spectral Doppler sampling could be performed in specific positions guided by the Doppler flow map to verify the phasic characteristics of the ductal shunt on spectral and audio outputs. Shunts through a very small patent ductus arteriosus were routinely detected in this group of infants, and right to left ductal shunts could also be verified by the Doppler flow mapping technique. This study suggests substantial promise for real-time two-dimensional Doppler echocardiographic flow mapping for evaluation of patent ductus arteriosus in infants.     

A pulsed Doppler echocardiographic study of the postnatal changes in pulmonary artery and ascending aortic flow in normal term newborn infants

Postnatal circulatory adaptations were studied with Doppler echocardiographic measures of flow velocity in the main pulmonary artery (PA) and ascending aorta (Ao) in 45 normal full-term neonates at 5 hours and at 27 hours after birth. PA flow velocity integral (FVI) was measured as the area under the systolic flow velocity curve and reflected total systemic flow in the presence of a left-to-right shunt through the ductus arteriosus. This index increased from 5 and 27 hours age, while Ao FVI, reflecting total pulmonary flow, remained unchanged. Evidence of a left-to-right ductal shunt demonstrated as diastolic retrograde flow in the main PA was detected in 42 neonates at 5 hours and in only four subjects after 27 hours of age, indicating a patent ductus arteriosus at 5 hours of age and its subsequent closure. In the PA, acceleration time (AT) increased while pre-ejection period to ejection time ratio (PEP/ET) decreased from 5 to 27 hours of age, reflecting the physiologic fall in PA pressure. In the Ao, FVI, AT, and PEP/ET remained unchanged, suggesting little change in left ventricular function.     

Valve-incompetent foramen ovale in premature infants with ductus arteriosus: a Doppler echocardiographic study

In a 1 year period, 56 neonates with a clinical diagnosis of ductus arteriosus had Doppler echocardiographic confirmation of the ductus; 33 (59%) had additional, turbulent left to right flow at the atrial level through a valve-incompetent foramen ovale. Normalized left atrial dimensions in the group with the atrial shunt were significantly larger than when there was a competent foramen ovale; when the ductus closed and left atrial enlargement receded, the atrial shunt disappeared. However, several infants with large left chambers had no interatrial shunting. When the atrial shunt was present, there were up to three flow pulses, corresponding to atrial systole, ventricular systole and ventricular diastole, but these were frequently fused into two pulses or even one pulse per cycle. The atrial septal morphology provided supporting clues: general bowing of the septum or a localized bulge in the region of the foramen ovale indicated relatively high left atrial pressure, and frequently a slitlike dropout could be seen at the superior edge of the foramen. During the study, three additional neonates with a ductus arteriosus were found to have a secundum atrial septal defect with a typical echographic image, "matchhead" appearance of the septal rim of the defect, but the Doppler flow patterns were indistinguishable from those of a valve-incompetent foramen ovale. The hemodynamic effects of the interatrial shunt, from either cause, seemed slight during the hospital course, but the presence of a valve-incompetent foramen ovale indicated a relatively large ductal shunt. Quantification of the ductal shunt, however, continues to rely primarily on measurement of the left atrial and ventricular size.     

Detection and quantitation of constriction of the fetal ductus arteriosus by Doppler echocardiography

Pulmonary hypertension may occur in the fetus in the presence of constriction of the ductus arteriosus. The feasibility of detection and quantitation of fetal ductal constriction by Doppler echocardiography was assessed in an animal preparation in which ductal constriction was created in the fetal lamb with a variable ligature causing varying degrees of fetal pulmonary hypertension (fetal pulmonary arterial systolic pressure 57 to 97 mm Hg and ductal gradient 9 to 42 mm Hg). Comparison of blinded, continuous-wave peak Doppler velocity (V) measurements of the ductal gradient with the modified Bernoulli assumption (gradient = 4V2) compared well with direct catheter measurements of instantaneous peak systolic gradient (r = .99, catheter = 0.95 X Doppler + 0.6), peak-to-peak gradient (r = .97), and mid-diastolic gradient (r = .85). Ductal constriction was characterized by an increase in the peak systolic and diastolic velocities. The normal human fetal ductus arteriosus blood flow velocity pattern was assessed by pulsed Doppler techniques in 25 normal human fetuses after 20 weeks gestation. The peak systolic flow velocity in the ductus arteriosus measured by image-directed pulsed Doppler echocardiography ranged from 50 to 141 cm/sec (mean 80 cm/sec) and increased with gestational age (r = .50). Diastolic velocity in the ductus arteriosus was consistently directed toward the descending aorta and ranged from 6 to 30 cm/sec. The ductal systolic velocities were the highest blood flow velocities in the fetal cardiovascular system. Application of these techniques to fetuses whose mothers were receiving indomethacin for treatment of premature labor at 30 to 31 weeks gestation confirmed this method to be sensitive for detection of fetal ductal constriction, which developed in three fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)     

Patency of the ductus arteriosus in normal neonates: two-dimensional echocardiography versus Doppler assessment

Two-dimensional echocardiography using a high resolution, 7.5 ,Jsz transduce was compared with Doppler echocardiography for the assessment of patency of the ductus arteriosus in normal newborn infants. Twenty-eight neonates were studied between 1 and 10 hours (mean 5.5) after birth and both examinations were possible in 27 (96%). Doppler echocardiography under two-dimensional direction indicated ductal patency in all 27 neonates. Doppler sampling in the pulmonary end of the ductus rather than the main pulmonary artery was more sensitive for detecting patency. When two-dimensional echocardiography only was used to predict patency, there was 85% sensitivity. Two-dimensional echocardiography showed no evidence of ductus arteriosus narrowing ion four neonates studied shortly after birth. In 18, the pulmonary portion of the ductus arteriosus appeared narrowed and in 8 of these, the narrowing extended toward the mid-portion of the ductus. In five others, there was only mid-ductus arteriosus narrowing. It is concluded that high resolution two-dimensional echocardiography can be used to assess ductus arteriosus morphology, but is limited in predicting ductal patency near the time of normal physiologic closure. Combined two-dimensional and Doppler echocardiography is a highly sensitive technique for detection of ductal patency when sampling is performed in the pulmonary end of the ductus arteriosus.     

Interatrial shunt flow profiles in newborn infants: a colour flow and pulsed Doppler echocardiographic study

Interatrial shunt flow profiles in 36 normal term infants were examined serially by colour flow and pulsed Doppler echocardiographic techniques from within an hour of birth to four or five days after birth. Shunt flow across the foramen ovale was detected in 33 normal infants (92%) within an hour of birth (mean 40 minutes). The occurrence of interatrial shunting decreased with age, but a shunt signal was still detected in 17 infants (47%) on the fourth or fifth day of life, by then the ductus arteriosus had already closed in all the normal infants. The direction of interatrial shunt flow was predominantly left-to-right, but in 64% there was a coexistent small right-to-left shunt in diastole within an hour of birth; by four to five days it was found in 19%. In the six patients with persistent fetal circulation the direction of the interatrial shunt flow was predominantly right-to-left with biphasic peaks in diastole and systole at the early stage of the disease, and the period of right-to-left shunt flow during each cardiac cycle was significantly longer than that in normal infants examined within 1 hour of birth. In all patients the ductus closed before the foramen ovale. At the time of ductal closure in all patients with persistent fetal circulation right-to-left shunt flow was seen during diastole and its period was still prolonged. These findings suggest that interatrial shunting, predominantly left-to-right, is common in normal newborn infants. Evaluation of the characteristics of the interatrial shunt by Doppler echocardiography may be useful for predicting the progress of or improvement in neonates with persistent fetal circulation.     

Interatrial shunt flow profiles in newborn infants: a colour flow and pulsed Doppler echocardiographic study.

Interatrial shunt flow profiles in 36 normal term infants were examined serially by colour flow and pulsed Doppler echocardiographic techniques from within an hour of birth to four or five days after birth. Shunt flow across the foramen ovale was detected in 33 normal infants (92%) within an hour of birth (mean 40 minutes). The occurrence of interatrial shunting decreased with age, but a shunt signal was still detected in 17 infants (47%) on the fourth or fifth day of life, by then the ductus arteriosus had already closed in all the normal infants. The direction of interatrial shunt flow was predominantly left-to-right, but in 64% there was a coexistent small right-to-left shunt in diastole within an hour of birth; by four to five days it was found in 19%. In the six patients with persistent fetal circulation the direction of the interatrial shunt flow was predominantly right-to-left with biphasic peaks in diastole and systole at the early stage of the disease, and the period of right-to-left shunt flow during each cardiac cycle was significantly longer than that in normal infants examined within 1 hour of birth. In all patients the ductus closed before the foramen ovale. At the time of ductal closure in all patients with persistent fetal circulation right-to-left shunt flow was seen during diastole and its period was still prolonged. These findings suggest that interatrial shunting, predominantly left-to-right, is common in normal newborn infants. Evaluation of the characteristics of the interatrial shunt by Doppler echocardiography may be useful for predicting the progress of or improvement in neonates with persistent fetal circulation.     

The newborn transitional circulation: a two-dimensional Doppler echocardiographic study

To characterize changes in circulation after birth, 11 normal full-term infants were examined with two-dimensional and pulsed Doppler echocardiography. The initial examination was performed within 10 hours after delivery and serially for 3 days. Retrograde diastolic pulmonary artery velocities, which are evidence for a patent ductus arteriosus, were detected in 10 infants (91%) on day 1, in 2 (18%) on day 2 and in none on day 3. Retrograde systolic descending aortic velocities, which are evidence of flow from the aorta into the ductus arteriosus, were observed in 10 infants (91%) on day 1, 9 (81%) on day 2 and 7 (64%) on day 3. Persistence of the retrograde systolic velocity in the descending aorta in the absence of retrograde diastolic velocity in the pulmonary artery is consistent with physiologic ductal closure beginning near the pulmonary artery end of the ductus arteriosus. Localized turbulent retrograde systolic flow, proximal to the septal leaflet of the tricuspid valve and consistent with tricuspid insufficiency, was detected in six patients (55%) on day 1, in eight (73%) on day 2 and in seven (64%) on day 3. Thus, tricuspid insufficiency appears to be a frequent observation in healthy newborns. Normal Doppler velocities in the great arteries and across the tricuspid and mitral valves of newborns up to 3 days of age are presented. These normal measures of intracardiac flow velocities may be used for comparison to identify abnormal flow profiles in newborns with congenital heart defects.     

The neonatal transitional circulation: a combined noninvasive assessment

Dramatic changes occur in the circulation of the newborn during the transition from fetal to neonatal life. Closure of the foramen ovale and ductus arteriosus, decrease in pulmonary vascular resistance, and improvement in right ventricular compliance are among these changes. These physiological-anatomical events were characterized by means of two-dimensional, Doppler and color flow echocardiography. Forty-five full-term infants (22 male, 23 female) were studied at a mean age of 4.2 hours (T1), 25.5 hours (T2), 49.8 hours (T3), and 73.8 hours (T4) by two-dimensional, Doppler and color flow echocardiography. At T1, T2, T3, and T4, the ductus arteriosus was patent by color flow echocardiography in 100%, 34%, 22%, and 11%, respectively. Conversely, patency of the ductus by Doppler alone was detected in 100% (T1), 13% (T2, T3), and 11% (T4). Reversal of flow in the descending aorta, reflective of diastolic ductal filling, was not sensitive in detecting ductal patency (T1 50%, T2 3%, T3 and T4 0%). The patency of the foramen ovale was noted to decrease over the course of the study. Right ventricular compliance was quantitatively assessed by pulsed-Doppler diastolic properties (E-to-A ratio). This changed significantly from T1 to T4 (0.90 to 0.97) reflecting improving compliance of the right ventricle. The ratio of acceleration to ejection time, a Doppler estimation measure of pulmonary vascular resistance, increased from 0.28 to 0.33 (T1 to T4) reflecting a decrease in pulmonary vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)     

The ductus arteriosus in healthy newborn infants studied by continuous Doppler guided by two-dimensional Doppler color echocardiography

To characterize the ductus arteriosus shunt after birth, 53 normal newborn infants (36-41 weeks gestation), appropriate in size for gestational age, were examined using two dimensional Doppler echocardiography directed continuous Doppler for evidence of patent ductus arteriosus. The infants were examined within six hours of birth, and every six-eight hours thereafter until ductus arteriosus shunt could no longer be detected. In 51/53 infants, an adequate examination was possible and ductus arteriosus was detected in every infant using the standard precordial approach. Using two dimensional Doppler echocardiography a yellow-orange-red jet, sometimes blue in the central area, directed at the lateral wall of the pulmonary artery was recorded; using continuous Doppler a diastolic or continuous spectral flow into the main pulmonary artery was recorded. Ductus arteriosus shunt could no longer be detected in 7 infants 12 hours after birth, in 26 infants 12-24 hours after birth, in 11 infants 24-36 hours after birth, in 5 infants 36-48 hours after birth and in 2 infants 48-60 hours after birth. A diastolic spectral Doppler flow was present in 38 infants and became continuous before duct closure in 27 infants. In 13 infants it was continuous at first examination and until the ductus arteriosus closure. Both diastolic or continuous spectral Doppler flow could present a flat waveform profile, or a protodiastolic or protosystolic peak velocity. The shunt peak velocity increased significantly with the age i.e. (1.5 +/- 0.7 m/sec mean and SD-), at first examination, vs 2.3 +/- 0.6 m/sec at last examination before ductus arteriosus closure (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Doppler echocardiographic measurement of pulmonary artery pressure from ductal Doppler velocities in the newborn

The ductal flow velocities in 37 newborns (group 1: persistent pulmonary hypertension [n = 16], transient tachypnea [n = 3], other [n = 2]; group 2: respiratory distress syndrome [n = 16]) were prospectively evaluated by Doppler ultrasound for the purpose of deriving systolic pulmonary artery pressures. Maximal tricuspid regurgitant Doppler velocity in 21 of these patients was used to validate the pulmonary artery pressures derived from ductal flow velocities. There was a significant linear correlation between tricuspid regurgitant Doppler velocity and pulmonary artery systolic pressure derived from ductal Doppler velocities in patients with unidirectional (pure left to right or pure right to left) ductal shunting (p less than 0.001, r = 0.95, SEE 8) and in those with bidirectional shunting (p less than 0.001, r = 0.95, SEE 4.5). Systolic pulmonary artery pressure in group 1 (67 +/- 13 mm Hg) was significantly higher than that in group 2 (39 +/- 10 mm Hg) (p less than 0.001). In those with bidirectional shunting, duration of right to left shunting less than 60% of systole was found when pulmonary artery pressure was systemic or less, whereas duration greater than or equal to 60% was associated with suprasystemic pulmonary artery pressures. Serial changes in pulmonary artery systolic pressure, reflected by changes in ductal Doppler velocities, correlated with clinical status in persistent pulmonary hypertension of the newborn. Persistently suprasystemic pulmonary artery pressure was associated with death in five group 1 patients. It is concluded that ductal Doppler velocities can be reliably utilized to monitor the course of pulmonary artery systolic pressures in newborns.     

Flow in the aorta and patent ductus arteriosus in infants with aortic atresia or aortic stenosis: a pulsed Doppler ultrasound study

We used pulsed Doppler ultrasound to determine the flow dynamics of the aorta and patent ductus arteriosus (PDA) in 21 infants (ages 1 to 16 days) with PDA and aortic atresia (n = 15) or aortic stenosis (n = 6). The flow within the PDA was recorded in 19, and was right-to-left during systole in all. There was a diastolic left-to-right PDA shunt in 11 patients with aortic atresia and in three with aortic stenosis, and the shunt was associated with large (3 to 11 mm in diameter) interatrial communications. In two patients with aortic atresia and three with aortic stenosis, however, the diastolic PDA shunt was from right to left, and the interatrial communications were small (0 to 2 mm in diameter). The right-to-left diastolic PDA shunting may be best explained by the relative pulmonary (high with left-sided inflow obstruction and a small interatrial communication) and systemic resistances. All patients with aortic atresia and three with aortic stenosis had retrograde systolic flow in the transverse aortic arch, probably resulting from inadequate left ventricular output. Antegrade diastolic flow in the transverse aortic arch toward the PDA was observed in all infants with aortic atresia and a left-to-right PDA shunt. Ascending aortic flow was recorded in 11 patients with aortic atresia, and was retrograde during diastole in each, the result of coronary perfusion. Application of pulsed Doppler ultrasound can lead to a better understanding of the hemodynamics and physiology of patients with congenital cardiovascular disease.     

Pulsed doppler echocardiographic evaluation of the cyanotic newborn: Identification of the pulmonary artery in transposition of the great arteries

During M mode echocardiographic evaluation of cyanotic newborn infants, one may find two ventricles and two great vessels, but not have proof of their identity. Identification of the great vessels is important in evaluation of possible transposition of the great arteries. In a series of 68 cyanotic neonates pulsed Doppler echocardtography was applied to test the hypotheses that (1) a patent ductus arterlosus in present in most cyanotic neonates, (2) the great vessel that receives diastolic ductal flow is the pulmonary artery, and (3) specific noninvasive identification of pulmonary artery will allow diagnosis or exclusion of transposition of the great arteries. On M mode examination, the relations of the great vessels were normal in 43 infants; in all, pulsed Doppler echocardiography detected a patent ductus arteriosus flowing into a normally positioned pulmonary artery. The cyanosis in these 43 patients was later proved to be of pulmonary origin. In eight infants, the relation of the great vessels suggested transposition, and in all eight, Doppler echocardiography detected a patent ductus flowing into the posterior great vessel, proved at angiocardiography to be the transposed pulmonary artery. In 17 patients, the relation of the great vessels was front to back, neither “normal” nor suggestive of classic d transposition. A patent ductus arterlosus, detected with pulsed Doppler echocardiography in all 17, flowed into the anterior great vessel in the 14 normal infants, and flowed into the transposed pulmonary artery in the 3 with proved transposition. It is concluded that ductal patency is prevalent in cyanotic neonates, and that pulsed Doppler echocardiographic detection of ductal flow can define the pulmonary artery; such definition is most helpful in resolving the question of transposition in infants with a relation of the great vessels that is neither normal nor suggestive of transposition.     

Noninvasive detection of pulmonary hypertension in patent ductus arteriosus by pulsed Doppler echocardiography.

Twenty-five patients with proven patent ductus arteriosus were examined by pulsed Doppler echocardiography (PDE) before invasive assessment. Ten patients had normal pulmonary artery pressures, and by PDE, pandiastolic ductal flow. Fifteen patients had elevation of mean pulmonary artery pressure, and by PDE, all had abbreviations of diastolic ductal flow. PDE correctly distinguished between patients with normal pressure and those with evidence of pulmonary hypertension; the ECG did not allow such differentiation. Detection by PDE of pulmonary hypertension complicating patent ductus arteriosus appears to be clinically useful.