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Biomedical subjects

W R Morrow

Publications and source records attributed to W R Morrow.

At least 37 records · Page 2Linked to original sources
PubMed1996

Quantification of myocardial blood flow and flow reserve in children with a history of Kawasaki disease and normal coronary arteries using positron emission tomography.

OBJECTIVES: The purpose of this investigation was to determine whether myocardial blood flow and flow reserve, based on quantitative measurements derived from positron emission tomographic (PET) imaging, would be globally impaired in children with a previous history of Kawasaki disease and normal epicardial coronary arteries. BACKGROUND: Kawasaki disease is an acute inflammatory process of the arterial walls that results in panvasculitis in early childhood. Children with a history of Kawasaki disease and normal epicardial coronary arteries were previously considered to have normal coronary flow reserve. However, recent studies have reported exercise-induced regional perfusion abnormalities on single-photon positron emission tomographic (SPECT) imaging. METHODS: We assessed myocardial blood flow and flow reserve at rest and during adenosine stress with nitrogen-13 ammonia and PET in 10 children with a history of Kawasaki disease and in 10 healthy young adult volunteers. All children had acute Kawasaki disease 4 to 15 years before the PET study. None of the children had epicardial coronary artery abnormalities at the acute stage of the disease or during follow-up, as assessed by echocardiography. RESULTS: Rest blood flows normalized to the rate-pressure product, an index of cardiac work, were similar in both the patients with Kawasaki disease and healthy adult volunteers (82 +/- 14 vs. 77 +/- 16 ml/100 g per min [mean +/- SD], p = NS). However, hyperemic blood flows were significantly lower in the patients with Kawasaki disease than in the control subjects (263 +/- 64 vs. 340 +/- 57 ml/100 g per min, p = 0.01). As a result, estimates of myocardial flow reserve were lower in the patients with Kawasaki disease than in the healthy young adult volunteers (3.2 +/- 0.7 vs. 4.6 +/- 0.9, p = 0.003). In addition, total coronary resistance was higher in the patients with Kawasaki disease than in the healthy adult volunteers (33 +/- 11 vs. 24 +/- 5 mm Hg/ml per g per min, p = 0.04). Quantitative analysis of perfusion images demonstrated no evidence of regional perfusion abnormalities. CONCLUSIONS: Children with a previous history of Kawasaki disease and normal epicardial coronary arteries exhibit normal rest myocardial blood flows but reduced hyperemic flows and flow reserve. The abnormal hyperemic blood flows and flow reserve suggest an impaired vasodilatory capacity, possibly due to residual damage of the coronary microcirculation.

Adenosine↗
PubMed1996

Acute results of balloon angioplasty of native coarctation versus recurrent aortic obstruction are equivalent. Valvuloplasty and Angioplasty of Congenital Anomalies (VACA) Registry Investigators.

OBJECTIVES: This study sought to compare the immediate results and risk factors for suboptimal outcomes of percutaneous balloon angioplasty for native versus recurrent aortic obstruction. BACKGROUND: Some cardiology centers have been reluctant to adopt balloon angioplasty for treatment of native aortic coarctation, while advocating balloon angioplasty over an operation for treatment of postsurgical or recurrent aortic obstruction. METHODS: Acute results were analyzed from 970 procedures (422 native and 548 recurrent lesions) performed between 1982 and 1995 in 907 patients from 25 centers. An acute suboptimal outcome was defined as one or more of the following: residual systolic pressure gradient > or = 20 mm Hg, residual proximal to distal systolic pressure ration > or = 1.33 or a major complication (death, aortic transmural tear, stroke). RESULTS: Bal loon angioplasty significantly (p = 0.0001) increased lesion diameter fo r both native (mean [+/= SD] 128 +/= 94%) and recurrent aortic obstruction (97 +/= 87%), with a significantly greater increase in the native group (p = 0.0001). A reduction in systolic pressure gradients was significant in both groups (p = 0.0001), but slightly higher (p = 0.01) for native (-74 +/- 24%) versus recurrent obstruction (-70 +/- 31%). Death associated with angioplasty was reported in 0.7% of patients with native and in 0.7% of patients with recurrent lesions (p = 1.00). An acute suboptimal outcome was noted with angioplasty in 19% of native and in 25% of recurrent lesions (p = 0.04). Significant independent risk factors included higher preangioplasty systolic gradient (odds ratio [OR] 1.39/10-mm Hg increment; 95% confidence interval [CI] 1.28 to 1.50, p = 0.0001), earlier study date (OR 0.92/1-year increment, 95% CI 1.02 to 1.26, p = 0.02) and recurrent obstruction (OR 1.39 vs. native lesions, 95% CI 1.00 to 1.94, p = 0.05). CONCLUSIONS: Acute results and complications of balloon angioplasty of native coarctation appear to be equivalent or slightly superior to those of recurrent aortic obstructions.

Adolescent↗
PubMed1995

Effect of ductal patency on organ blood flow and pulmonary function in the preterm baboon with hyaline membrane disease.

OBJECTIVE: To examine the effect of early ductal ligation vs. maintenance of ductal patency on vital organ perfusion and pulmonary function in premature baboons with hyaline membrane disease. DESIGN: Randomized, controlled interventional study to compare early ligation with formalin infiltration of the ductus arteriosus. SETTING: Animal care facility at a dedicated research foundation. SUBJECTS: Eighteen premature baboons delivered by hysterotomy at 140 +/- 2 day gestation. INTERVENTION: Nine premature baboons underwent formalin infiltration of the ductus arteriosus (group 1), and nine underwent ductal ligation (group 2). Surgical ligation or formalin infiltration was performed at 2 to 4 hrs of age. Animals were maintained on mechanical ventilation and ventilator parameters were adjusted to maintain PaO2 and PaCO2 within the physiologic range. MAIN OUTCOME MEASURES: Left ventricular output indexed to body weight and vital organ perfusion were measured at 24 hrs of age by the radiolabeled microsphere method. Lung mechanics, including lung wet/dry weight ratio, total lung water, static compliance and functional residual capacity were measured immediately following euthanasia. RESULTS: Total pulmonary blood flow was significantly lower (p = .0001) in group 2 (mean = 94 mL/min/kg), compared with group 1 (mean = 287 mL/min/kg). Systemic blood flow and effective pulmonary blood flow were higher in group 1 (p = .07). No significant difference between groups in absolute organ blood flow was noted, although flow as a percent of left ventricular index was significantly higher in all organs except the kidney in group 2. There was no difference in arterial blood gas values, parameters of mechanical ventilation, percent lung water, or postmortem measurement of lung mechanics between groups. CONCLUSION: Early ductal ligation did not result in improved cardiac output, increased organ blood flow, or improved pulmonary function. We postulate that gradual constriction of the ductus arteriosus may play an important role in successful cardiovascular adaptation in the premature infant. While it is clear that premature infants with symptomatic patent ductus arteriosus often benefit from ductal closure, we question the practice of prophylactic early ductal closure.

Adrenal Glands↗
PubMed1994

Balloon angioplasty with stent implantation in experimental coarctation of the aorta.

BACKGROUND: Balloon angioplasty of coarctation of the aorta is an effective method of treatment but is complicated by tearing of the aortic intima, formation of aneurysms, and restenosis. Stent placement at the time of balloon dilation could prevent restenosis and could also prevent progression of intimal tears to aneurysms. The purpose of this study was to evaluate the feasibility of balloon dilation and implantation of balloon-expandable stents in an experimental model of coarctation and to examine the effect of stent placement at the site of surgically created stenosis. METHODS AND RESULTS: Coarctation of the aorta was surgically produced in 11 juvenile swine. Simultaneous coarctation angioplasty and stent implantation was performed in 10 animals 34 +/- 7.8 days after surgery. Repeat catheterization was performed 59 +/- 6 days after stent implantation. Five animals underwent reexpansion of stents with subsequent follow-up catheterization. Aortic specimens were examined by light microscopy and scanning electron microscopy. Coarctation angioplasty with stent implantation was successful in all, with an increase in coarctation diameter from 46 +/- 8.5% to 90 +/- 12.2% of proximal aortic diameter (P = .0001). Systolic pressure gradient decreased from 32 +/- 19.8 to 0.5 +/- 2.8 mm Hg (P < .001). All stents were patent at follow-up catheterization, with no evidence of intraluminal thrombosis. Reexpansion in five animals increased the stent diameter from a mean of 77.4 +/- 12.1% to 93 +/- 11.0% of proximal aortic diameter (P = .02). Gross examination of aortic specimens demonstrated formation of neointima over the stent wherever the stent struts were in contact with the aortic wall. The stent occupied a subintimal position and produced minimal compression of the underlying media. Medial compression was noted immediately beneath stent struts, but there was no evidence of intimal or medial dissection. CONCLUSIONS: Balloon angioplasty with simultaneous implantation of balloon-expandable stents is effective in relieving aortic obstruction in experimental coarctation. Reexpansion of the rigid stent can be performed in an area of surgical aortotomy and coarctation without significant intimal or medial injury. Stent implantation may be useful in preventing restenosis and aneurysm formation after angioplasty of coarctation.

Angioplasty, Balloon↗
PubMed1993

Balloon expandable intravascular stents: aortic implantation and late further dilation in growing minipigs.

Intravascular stents have been implanted in children with congenital and acquired vascular stenoses. Little information is known regarding the long-term results in growing patients, the implantation of multiple stents (in series), and the feasibility of further dilation. Nine stents were implanted in the abdominal aortas of 6 mini-pigs; in 3 pigs, 2 stents were implanted in series. Five pigs were recatheterized 196 +/- 17 days after stent implant. All stents were patent, with mild narrowing at the stent relative to the adjacent aorta; further stent dilation was performed. The stent diameter increased from 8.3 +/- 0.6 mm to 11.2 +/- 1.3 mm (p = 0.002), and the narrowing was relieved. These five pigs were catheterized 253 +/- 73 days after stent redilation. Each stent was patent without narrowing or pressure gradient. We conclude that intravascular stents do not interfere with normal growth, can be implanted in series, and can be further dilated.

Animals↗
PubMed1993

Re-expansion of balloon-expandable stents after growth.

OBJECTIVES: The purpose of this study was to evaluate the feasibility of re-expansion of balloon expandable intravascular stents and to examine the gross and histologic effects of re-expansion on vascular integrity. BACKGROUND: Intravascular stents have been used successfully as an adjunct to balloon dilation of congenital pulmonary artery branch stenosis and postoperative stenosis of the pulmonary arteries in children. However, use of rigid stents in children could result in development of relative stenosis at the site of stent implantation with subsequent growth of the child. METHODS: Stainless steel "iliac" stents were placed in the thoracic aorta of 10 normal juvenile swine by a transcatheter technique. Angiography and re-expansion were performed at a mean of 11 weeks (n = 9) and again at 18 weeks (n = 5). After euthanasia, the aortic specimens were removed for gross and histologic examination. RESULTS: Stents were successfully implanted in 10 swine. Re-expansion was successfully performed in each animal at 11 weeks and at 18 weeks. Aortic growth produced a relative constriction of the aorta of 20% +/- 10% (mean +/- SD) at the site of stent implantation at both 11 and 18 weeks. Re-expansion produced a significant increase in mean stent diameter from 10.1 +/- 1 mm to 12.3 +/- 1.2 mm at 11 weeks and from 11.2 +/- 0.7 to 13.5 +/- 1.1 mm at 18 weeks after implantation (p < 0.001). Balloon dilation produced a relative increase in stent diameter of 21% +/- 7% at 11 weeks and 18% +/- 4% at 18 weeks. Stent re-expansion was accompanied by plastic deformation of the neointima without neointimal dissection. Where neointima was thick, there was no evidence of neointimal abrasion, but where neointima was thin, areas of localized neointimal abrasion were observed with focal fibrin and platelet adherence to the stent struts. There was no evidence of medial or adventitial hemorrhage or dissection produced by re-expansion. CONCLUSIONS: Re-expansion of intravascular stents is feasible after growth in juvenile swine without significant injury to neointima, media or adventitia. The results of this study support careful and selective use of intravascular stents as an adjunct to balloon dilation of congenital stenoses in children.

Animals↗
PubMed1991

Cardiac output by Doppler echocardiography in the premature baboon: comparison with radiolabeled microspheres.

Pulsed-Doppler echocardiography (PDE) is a useful noninvasive method for determining left ventricular output (LVO). However, despite increasingly widespread use in neonatal intensive care units, validation studies in prematures with cardiopulmonary disease are lacking. The purpose of this study was to compare radiolabeled microsphere (RLM) and PDE measurements of LVO, using the critically ill premature baboon as a model of the human neonate. Twenty-two paired RLM and PDE measurements of LVO were obtained in 14 animals between 3 and 24 h of age. Average PDE LVO was 152 ml/min/kg (range, 40-258 ml/min/kg) compared to 158 ml/min/kg (range, 67-278 ml/min/kg) measured by RLM. Linear regression analysis of the paired measurements showed good correlation with a slope near unity (gamma = 0.94x + 4.20, r = 0.91, SEE = 25.7 ml). We conclude that PDE determinations of LVO compare well with those measured by RLM in the premature baboon. PDE appears to provide a valid estimate of LVO and should be useful in human prematures with cardiopulmonary distress.

Animals↗
PubMed1991

Transesophageal echocardiography in aortopulmonary communications.

The assessment of congenital aortopulmonary communications by transthoracic echocardiography may be suboptimal, particularly postoperatively, due to limited acoustic windows. We performed intraoperative transesophageal echocardiograms in six patients with eight proven systemic-pulmonary communications. Diagnosis included truncus arteriosus (1), aortopulmonary window (1), Waterston anastomosis (3), central Gore-Tex shunt (1), and modified left Blalock-Taussig shunt (2). All communications were accurately demonstrated by transesophageal echocardiography (TEE). The transesophageal technique also provided an assessment of the size of the aortopulmonary communications and the proximal pulmonary arteries. In addition, the gradient across some of the communications could be accurately estimated utilizing the high pulse repetition frequency Doppler. On the other hand, only two of the seven aortopulmonary communications were detected by transthoracic echocardiography. Postoperatively, transesophageal imaging demonstrated unobstructed conduit in five of five patients who underwent conduit repair, as well as intact closure of aortopulmonary communications and concomitant closure of ventricular septal defects.

Aortopulmonary Septal Defect↗
PubMed1991

High-frequency oscillatory ventilation versus intermittent mandatory ventilation: early hemodynamic effects in the premature baboon with hyaline membrane disease.

We studied the hemodynamic consequences during the first 24 h of life in premature baboons (140 d) with hyaline membrane disease that were treated with high-frequency oscillatory ventilation (HFOV) or conventional intermittent mandatory ventilation (IMV). Cardiac output and organ blood flow were measured at three time-points using the radiolabeled microsphere technique. Seven of seven HFOV and six of eight IMV animals survived the 24-h period. By design, initial mean airway pressure (Paw) was higher in the HFOV group (p less than 0.01). HFOV Paw was progressively reduced during the study period because of improving oxygenation as measured by the arterial to alveolar oxygen ratio. In contrast, it was necessary to increase Paw in the IMV animals to maintain the arterial to alveolar oxygen ratio. By 23 h, the IMV group required higher Paw than the HFOV group (p less than 0.05) and had a lower arterial to alveolar oxygen ratio (p less than 0.05). We found no significant differences in left ventricular output, effective systemic flow, organ blood flow, or central venous pressure between the two groups at 3, 8, or 23 h. The HFOV strategy used in our study resulted in significant improvement in oxygenation during the initial 24 h of treatment without adverse effect on left ventricular output, cerebral blood flow, or central venous pressure. We conclude that when appropriate changes in Paw are made during HFOV in response to improvement in arterial oxygenation and changes in lung inflation as assessed by chest radiographs HFOV can be achieved without depressing cardiovascular dynamics more than during conventional therapy with IMV.

Animals↗
PubMed1990

Transplacental transfer of zidovudine in the near-term pregnant baboon.

Approximately one third of infants born to human immunodeficiency virus type 1 seropositive mothers have evidence of infection or of acquired immunodeficiency syndrome by the age of 18 months. One fifth of infected infants also have died by age 18 months. This prevalence, combined with the demonstration that zidovudine (formerly azidothymidine) can decrease mortality and the frequency of opportunistic infections in patients with acquired immunodeficiency syndrome or acquired immunodeficiency syndrome--related complex, may lead to increasing use of azidothymidine in pregnancy despite a paucity of information regarding its pharmacokinetics. To further investigate the distribution of azidothymidine and its inactive metabolite 5'-glucuronide azidothymidine in the mother, fetus, and amniotic fluid, 12 near-term pregnant baboons were given oral azidothymidine (21 mg/kg/day in four divided doses every 6 hours, equivalent to the usual nonpregnant human dose of 1500 mg/day). Specimens of maternal blood, fetal arterial blood obtained by percutaneous umbilical cord blood sampling, and amniotic fluid were obtained after from one to 17 doses of azidothymidine. Azidothymidine levels were measured by radioimmunoassay with the INCSTAR commercial radioimmunoassay kit and using Escherichia coli beta-glucuronidase for determination of 5'-glucuronide azidothymidine levels. Paired analyses revealed significant concentration gradients between amniotic fluid, fetal serum, and maternal serum for both azidothymidine (p less than 0.019) and 5'-glucuronide azidothymidine (p less than 0.002). The amniotic fluid 5'-glucuronide azidothymidine level increased with increasing doses of azidothymidine despite the fact that the maternal azidothymidine and 5'-glucuronide azidothymidine concentrations were unchanged. This accumulation of amniotic fluid 5'-glucuronide azidothymidine may provide a functional drug reservoir and contribute to the higher fetal concentrations of the medication and its metabolite. Alternatively, the higher fetal levels may represent slower clearance in the fetus than in the mother. Further studies appear warranted with respect to possible adverse fetal effects, especially bone marrow suppression with prolonged and chronic exposure to azidothymidine.

Amniotic Fluid↗
PubMed1990

Left ventricular dysfunction following ligation of the ductus arteriosus in the preterm baboon.

We evaluated the effect of early closure of the patent ductus arteriosus (PDA) on cardiac performance in a preterm baboon model of hyaline membrane disease. Eleven baboon fetuses were delivered at 75% gestation, resuscitated, and treated with conventional ventilation. The animals were divided into two groups, and underwent left thoracotomy at 2 hr of age. Group 1 (N = 5) had ductal infiltration with formalin to maintain ductal patency. Group 2 (N = 6) had ductal ligation. Hemodynamic parameters were compared between groups before and after surgical intervention. Examination of cardiovascular function was performed at intervals over a 24-hr period using two-dimensional, M-mode, and pulsed Doppler echocardiography. Ventricular performance was significantly worse in the ligation animals as demonstrated by reduced left and right ventricular outputs and reduced left ventricular shortening. However, pulmonary disease and arterial blood gases were not different. Early ligation was also associated with significantly increased systemic vascular resistance. We conclude that early ductal ligation leads to impaired ventricular performance in the premature primate. We hypothesize that the PDA may protect the immature ventricle by preventing pressure overload during adaptation to postnatal life.

Animals↗
PubMed1988

An unusual cardiomelic syndrome.

We report on a patient with pre- and postnatal growth retardation, bilateral symmetrical ulnar agenesis with monodactyly, atrial septal defect, two ventricular septal defects, Wolff-Parkinson-White conduction abnormality, and abnormal configuration of the pancreas. Although she had some facial features reminiscent of the Brachmann-de Lange syndrome, relatively normal head size and motor development indicate a distinct syndrome.

Abnormalities, Multiple↗
PubMed1988

Continuous wave Doppler cardiac output: use in pediatric patients receiving inotropic support.

Doppler estimates of cardiac output have been shown to correlate closely with invasive measurement of cardiac output in hemodynamically stable adults and children. However, this method has not been validated in hemodynamically unstable pediatric patients. To assess the accuracy of continuous wave Doppler echocardiography in pediatric patients with unstable hemodynamics, we performed 27 simultaneous Doppler and thermodilution comparisons in 12 pediatric patients receiving inotropic support and afterload-reducing agents. Doppler cardiac output was calculated using aortic diameter measured from long-axis two-dimensional echocardiograms at three different sites: the aortic valve anulus, the aortic root at the sinuses of Valsalva, and the ascending aorta. For all measurements, there was a close correlation between Doppler and thermodilution techniques. However the site of measurement of aortic diameter had a significant impact on the strength on the correlation and the variability between Doppler and thermodilution. The best correlation and least variability were obtained using the aortic valve anulus diameter (r = 0.94). On serial determinations, percent change in Doppler stroke volume correlated well with thermodilution stroke volume (r = 0.87) and was useful in detecting both direction and magnitude of change in thermodilution stroke volume. Despite the administration of positive inotropic and afterload-reducing agents, Doppler cardiac output is a useful method for estimating cardiac output in hemodynamically unstable pediatric patients.

Adolescent↗
PubMed1988

Balloon dilation of unoperated coarctation of the aorta: short- and intermediate-term results.

Balloon dilation is effective in the immediate relief of obstruction due to unoperated coarctation of the aorta. However, the long-term benefits and complications of this procedure have not been established. Thirty-three patients underwent balloon dilation of unoperated coarctation using a percutaneous technique from November 1983 to December 1985. High quality biplane angiography was performed before and after dilation. Follow-up was obtained in 20 patients from 6 to 31 months following dilation. Angiography was performed at follow-up in 10, nuclear magnetic resonance (NMR) imaging in 10 and both NMR imaging and angiography in 3. Balloon dilation was successful in 31 of the 33 patients with a decrease in average systolic pressure gradient from 46 to 8 mm Hg. There was no significant change in gradient on follow-up physical examination and at recatheterization in 10 patients. In addition, there was no evidence of restenosis on follow-up angiography and NMR imaging. In two patients, a small aneurysm formed at the site of balloon dilation. Balloon dilation of unoperated coarctation is effective, providing lasting relief of coarctation gradient and no evidence of restenosis. However, because of the uncertain natural history of aneurysms after dilation, this procedure should be considered investigational until further follow-up on patients with and without an aneurysm is available.

Angiography↗
PubMed1987

Pulmonary venous and systemic ventricular inflow obstruction in patients with congenital heart disease: detection by combined two-dimensional and Doppler echocardiography.

Obstruction to pulmonary venous return may be associated with a number of congenital cardiovascular abnormalities occurring both before and after surgery. Hemodynamic assessment by cardiac catheterization is often difficult. A noninvasive method for detection and quantitation of obstruction to systemic ventricular inflow would be clinically useful. Two-dimensionally directed pulsed and continuous wave Doppler echocardiography was performed before cardiac catheterization in 31 patients thought clinically to have possible obstruction to left ventricular inflow or pulmonary venous return. Primary diagnoses included transposition of the great arteries after the Mustard or Senning procedure in nine patients, total anomalous pulmonary venous connection in nine (in two after surgical repair), cor triatriatum in eight (in four after surgical repair), congenital mitral stenosis in four (in one after surgical repair) and mitral atresia in one. Severe obstruction was defined as a mean pressure gradient at catheterization of greater than or equal to 16 mm Hg at any level of the pulmonary venous return or of the systemic ventricular inflow. Severe obstruction was predicted if Doppler examination measured a flow velocity of greater than or equal to 2 m/s across any area of inflow obstruction. At catheterization, 12 patients (39%) had severe obstruction to left ventricular inflow or pulmonary venous return and all obstructions were correctly detected by Doppler echocardiography. The site of pulmonary venous obstruction was localized by two-dimensionally directed pulsed Doppler study. Patients with a lesser degree of obstruction had a lower Doppler velocity, but none had a maximal Doppler velocity of greater than or equal to 2 ms/s.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Small bowel obstruction as a complication of Kawasaki disease.

A case of small bowel obstruction in an 8-month-old infant with Kawasaki disease is described. At laparotomy a discrete area of jejunal stricture with adhesions was noted. Microscopic examination revealed evidence of small artery thrombosis. Kawasaki disease results in a diffuse vasculitis, which may produce significant abnormalities in multiple organ systems. Serious abdominal complications can occur and should be considered when gastrointestinal symptoms develop in a patient with Kawasaki disease.

Humans↗
PubMed1986

Quantitative morphology of the aortic arch in neonatal coarctation.

It has been speculated that neonatal coarctation results from postnatal constriction of the aortic isthmus and ductus arteriosus. However, aortic arch hypoplasia is present in some neonates with coarctation and is presumed to be due to decreased aortic arch blood flow in utero. To measure the degree of aortic arch hypoplasia and to analyze the distribution of blood flow in neonatal coarctation, quantitative morphometric analysis of the great vessels from two-dimensional echocardiograms was performed in 14 neonates with isolated coarctation and 14 normal control neonates, all less than 1 month old. Measurements of the aortic valve, pulmonary valve, ascending aorta, transverse aortic arch between the carotid and subclavian arteries, aortic isthmus, descending aorta, main pulmonary artery and brachiocephalic vessels were obtained to the nearest 0.5 mm. In coarctation patients the transverse arch and isthmus were significantly smaller than in control subjects (p less than 0.001). In addition, pulmonary valve and main pulmonary artery diameters were significantly greater in neonates with coarctation than in normal neonates. Transverse arch hypoplasia and increased pulmonary valve and pulmonary artery diameters are present in neonates with coarctation. This suggests decreased aortic arch flow and increased pulmonary and ductus arteriosus flow in utero, which produce a characteristic echocardiographic appearance of transverse arch hypoplasia with a large main pulmonary artery.

Aorta, Thoracic↗