Echocardiographic study of the morphology and growth of the aortic arch in the human fetus. Observations related to the prenatal diagnosis of coarctation.

BACKGROUND. In a study of normal and abnormal growth of the aorta before birth, high-resolution echocardiographic imaging of the aortic arch in 92 normal fetuses aged 16-38 weeks was used to establish normal values for aortic arch dimensions at varying gestational ages. METHODS AND RESULTS. From long-axis views of the aortic arch, the internal diameter of the aortic root, ascending aorta, transverse aortic arch, aortic isthmus, proximal descending thoracic aorta, and left common carotid artery were measured. Correlation coefficients for the diameter of each aortic arch segment when related to gestational age varied from r = 0.87 to r = 0.94 (p less than 0.001 for each), and growth curves were derived from the third and 97th percentiles around each linear regression analysis. In most of the fetuses, there was progressive tapering of the aortic arch, with the smallest diameter being at the isthmus. The ratio of the transverse aorta, isthmus, descending aorta, and aortic root to the ascending aorta remained relatively constant with gestational age, with mean values of 0.94, 0.81, 0.96, and 1.13, respectively. In five fetuses in whom a prenatal diagnosis of aortic coarctation was confirmed postnatally, transverse aortic and isthmic measurements fell on or below the third percentile for gestational age from the above data. In each case, the ratio of left common carotid artery to transverse aorta was greater than or equal to 0.73 compared with less than or equal to 0.62 for the 92 normal fetuses (mean ratios, 0.77 +/- 0.05 [SD] for coarctation versus 0.48 +/- 0.08 for normal fetuses; p less than or equal to 0.001). CONCLUSIONS. Use of normal growth curves for the developing aortic arch should facilitate the prenatal diagnosis of left heart and aortic arch abnormalities, particularly aortic coarctation, which until recently has been a difficult prenatal diagnosis to make with certainty.     

Hypoplastic left heart syndrome: is echocardiography accurate enough to guide surgical palliation?

Two-dimensional echocardiography can diagnose hypoplastic left heart syndrome. However, with the advent of the possibility of palliative open heart surgery, complete anatomic diagnosis is necessary. The anatomic findings of 15 neonates with hypoplastic left heart syndrome (age 1 to 10 days, mean 4.1) who had two-dimensional Doppler echocardiographic studies were compared with the results obtained by angiography (6 cases), surgery (11 cases) and autopsy (8 cases). Complete two-dimensional echocardiographic examination of the aortic arch, pulmonary and systemic venous return, atrial septum, ductus arteriosus and proximal coronary arteries was possible in all 15 neonates and correctly diagnosed hypoplastic left heart syndrome in each. Anatomic two-dimensional echocardiographic assessment was accurate in 13 (86%) of the 15 neonates and there were no false positive results. Undiagnosed associated abnormalities were hypoplasia of a left pulmonary artery in one patient and left superior vena cava in another. Accurate quantitation of the size of the tricuspid valve anulus, ascending aorta, pulmonary anulus and right and left pulmonary arteries was possible. Doppler examination was performed in seven patients and confirmed retrograde aortic arch flow and right to left systolic shunting in the patent ductus arteriosus. In selected neonates, surgical palliation can be attempted without angiography.     

Coarctation and related aortic arch anomalies in hypoplastic left heart syndrome

The aortic arches of 34 specimens with hypoplastic left heart syndrome were studied in order to establish the frequency, the nature and the clinical implications of aortic arch anomalies. A localized aortic coarctation was present in 23 specimens. The coarcation was located preductally in 2 and paraductally in 21 cases. The degree of obstruction caused by the coarctation varied considerably. In only 6 cases (1 preductal and 5 paraductal) was the obstruction judged to be severe. One of these cases had an additional aneurysm of the aortic wall proximal to the coarctation. An aberrant relation of the ductus arteriosus and the aortic arch was found in 2 specimens without localized coarctation. In the remaining 9 specimens the aortic arch appeared normal. The aortic arch anomalies were mostly present in specimens with a severely hypoplastic ascending aorta. Clinicians, when preparing infants with hypoplastic left heart syndrome for surgical palliation, should always suspect associated aortic arch anomalies, especially when there is severe hypoplasia of the ascending aorta. Coarctation of the aorta will require additional surgical treatment.     

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.     

Hypoplastic right retro-oesophageal aortic arch: similarities to interrupted aortic arch.

At echocardiography a dysmorphic neonate was found to have a hypoplastic mitral valve, left ventricle, and ascending aorta with interruption of the aortic arch between the left common carotid and the left subclavian arteries--the left subclavian artery arose from a normal sized left descending aorta. Cardiac catheterisation and subsequent necropsy confirmed this arrangement but also showed a tortuous right retro-oesophageal aortic arch. This arch was severely hypoplastic distal to the right subclavian artery. These cardiovascular anomalies occurred in the child of a family in which other members showed the velo-cardio-facial syndrome, a condition known to be associated with right aortic arch. This aortic arch arrangement may be impossible to distinguish from simple aortic interruption by echocardiography alone.     

Hypoplastic right retro-oesophageal aortic arch: similarities to interrupted aortic arch

At echocardiography a dysmorphic neonate was found to have a hypoplastic mitral valve, left ventricle, and ascending aorta with interruption of the aortic arch between the left common carotid and the left subclavian arteries--the left subclavian artery arose from a normal sized left descending aorta. Cardiac catheterisation and subsequent necropsy confirmed this arrangement but also showed a tortuous right retro-oesophageal aortic arch. This arch was severely hypoplastic distal to the right subclavian artery. These cardiovascular anomalies occurred in the child of a family in which other members showed the velo-cardio-facial syndrome, a condition known to be associated with right aortic arch. This aortic arch arrangement may be impossible to distinguish from simple aortic interruption by echocardiography alone.     

Antegrade flow in the aorta ascendens despite aortic atresia: 2 case reports with retrograde coronary perfusion through coronary fistulas and sinusoids

In aortic atresia, coronary perfusion normally occurs through retrograde blood flow in the ascending aorta. We report on two patients with antegrade flow in the ascending aorta despite aortic atresia. In one patient with hypoplastic left heart syndrome (aortic atresia, severe mitral stenosis), an intact interatrial septum/premature closure of the foramen ovale was found. While no other way of left atrial or ventricular decompression was found, echocardiography, angiography and the post-mortem examination showed left ventricular to coronary sinusoids as the sole pathway for systemic oxygenation. In a second patient with complex congenital heart disease, including aortic atresia, antegrade flow in the ascending aorta was through a left coronary fistula with shunt flow originating from the pulmonary trunk. This report describes systemic perfusion depending on retrograde coronary flow due to coronary-cameral (sinusoids) and coronary arterio-venous fistulas leading to the phenomenon of antegrade blood flow in the ascending aorta despite aortic atresia.     

Biventricular repair in neonates with hypoplasia of the left ventricle]

BACKGROUND: Whether to perform uni or biventricular repair in ducto dependent neonates with hypoplastic but morphologically normal left ventricle and multi level left ventricle obstructions (hypoplastic left heart syndrome class III) remains unanswered. Echocardiographic criteria have been proposed for surgical decision. HYPOTHESIS: Increased afterload and multi level left ventricle obstruction is constant. We assumed that restoration of normal loading conditions by relief of left ventricle obstructions promotes its growth, provided that part of the cardiac output was pre operatively supported by the left ventricle, whatever the echocardiographic indices. METHODS: Twenty one ducto dependent neonates presented with this anomaly. All had aortic coarctation associated to multi level left ventricle obstruction. Pre operative echocardiographic assessment showed: mean end diastolic left ventricular volume of 13.3 +/- 3.5 mL/m2 and mean Rhodes score of -1.43 +/- 0.9. Surgery consisted in relief of left ventricle outflow tract obstruction by coarctation repair in 21 associated to atrial septal defect closure in 2, aortic commissurotomy in 1 and ascending aorta enlargement in 1. RESULTS: There were 3 early and 3 late deaths. There was no predictive risk factor for failure. Growth of the left heart was demonstrated in most patients. At hospital discharge the end diastolic left ventricular volume was 19.4 +/- 3.12 mL/m2 (p = 0.0001) and the Rhodes score was -0.38 +/- 1.01 (p = 0.0003). Actuarial survival and freedom from reoperation rates at 5 years were: 68.5% and 40.75%, respectively. CONCLUSION: Biventricular repair can be proposed to ducto dependent neonates with hypoplastic but morphologically normal left ventricle provided that all anatomical causes of left ventricle obstruction can be relieved. Secondary growth of the left heart then occurs, however the reoperation rate is not low.     

Hypoplastic left heart syndrome: experience with palliative surgery

Aortic atresia is a form of hypoplastic left heart syndrome always complicated by associated severe hypoplasia of the ascending aorta and various degrees of mitral valve and left ventricular hypoplasia. At present it is a universally fatal lesion in early infancy. This is a report of a new palliative procedure for hypoplastic left heart syndrome that has resul;ed in early ongoing survival of two infants with aortic atresia. On the basis of experience with a third patient, an operation for future physiologic correction is proposed.     

An infant with hypoplastic left heart syndrome and spinal muscular atrophy

We report an infant with hypoplastic left heart syndrome consisting of mitral valvar atresia, aortic valvar atresia, hypoplasia of the aortic arch and coarctation of the aorta, who demonstrated respiratory failure and global hypotonia, and who was eventually diagnosed with spinal muscular atrophy.     

Anomalous origin of the left main pulmonary artery from the ascending aorta associated with Digeorge syndrome

We place on record 2 infants with the DiGeorge syndrome and anomalous origin of the left pulmonary artery from the ascending aorta. We postulate that: (1) embryogenesis of anomalous origin of the left pulmonary artery from the ascending aorta might be due to the persistent fifth aortic arch connecting both arterial systems; (2) an anomalous pulmonary artery arising from the ascending aorta is part of the aortic arch abnormality accompanied by normal conotruncal septation; and (3) in the DiGeorge syndrome, cardiac anomalies that originate from the conotruncus or aortic arch, or both, may have the same embryologic mechanisms.     

Selective aortic root angiography in the hypoplastic left heart syndrome.

Selective aortic root angiography was performed in 18 patients with the clinical diagnosis of hypoplastic left heart syndrome in order to allow more precise correlation with echocardiography. Aortic valve atresia and severe hypoplasia of the left heart chambers subsequently were substaniated at necropsy in each instance. Wide variation in the size and shape of the aortic root and ascending aorta was demonstrated angiographically in these patients. In some patients, despite aortic valve atresia, the dimensions of the aortic root and sinuses of Valsalva at angiography were almost normal. In addition, this technique allowed the demonstration of primitive vascular communications between the coronary artery and left ventricular cavity in 1 patient (coronary-cameral fistula). The realization that the aortic root may approach nearly normal size in some patients with the hypoplastic left heart syndrome is essential to the echocardiographic diagnosis of this disease and to the differential diagnosis from other cardiac and noncardiac causes of severe neonatal congestive heart failure.     

Congenitally corrected transposition and Ebstein's anomaly of the systemic atrioventricular valve: association with aortic arch obstruction

Aortic arch abnormalities are uncommon in patients with congenitally corrected transposition of the great arteries. Over a 20-year period, 10 patients with congenitally corrected transposition and Ebstein's anomaly of the systemic atrioventricular (AV) valve were identified. Five neonates had severe systemic AV valve regurgitation with severe coarctation of the aorta (n = 4) or aortic atresia (n = 1) and presented with heart failure. Four died in the neonatal period and one who had coarctation repair died 7 months postoperatively. The remaining five patients with congenitally corrected transposition and Ebstein's anomaly had mild left AV valve regurgitation; none of these had aortic arch obstruction. In neonates who have coexisting Ebstein's anomaly of the systemic AV valve and congenitally corrected transposition, obstruction to aortic arch flow is common. Severe systemic AV valve regurgitation with a morphologic systemic right ventricle may have contributed to low anterograde flow in the ascending aorta prenatally and thereby to the aortic arch abnormality.     

Growth characteristics of the aortic arch after the Norwood operation

Objectives. We sought to characterize the growth of the reconstructed aortic arch after the Norwood operation (NO).

Background. The first stage of surgical palliation of hypoplastic left heart syndrome (HLHS), the NO, includes augmentation of the aortic arch with homograft. Growth characteristics of the reconstructed aortic arch, which is comprised of both native aortic tissue and homograft, have not been characterized.

Methods. Retrospectively, we examined the serial echocardiograms of 50 patients with HLHS who underwent NO to determine the diameter of the reconstructed transverse arch. Measurements were taken immediately after NO and at two other points (1 to 11 years of age). In addition, the autopsy specimens of 10 other patients with HLHS who underwent NO were examined to determine the contribution of native aortic tissue to the overall size of the reconstructed arch at the time of death (12 to 34 months).

Results. The diameter of the transverse aorta increased after NO in all subjects. Its rate of growth paralleled that seen in the normal population, though the reconstructed arch had a significantly larger diameter throughout childhood. Examination of autopsy specimens demonstrated a mean increase in circumference of the native aortic tissue of 0.67 cm (p value <0.01), whereas there was no significant change in homograft circumference.

Conclusions. After reconstruction of the aortic arch in HLHS, the diameter of the arch continues to increase throughout childhood, and this increase is due to growth of the native aortic tissue.     

Absence of the aortic valve associated with hypoplastic left-sided heart syndrome

In this report we describe the twelfth case in the literature of absence of the aortic valve cusps, associated with hypoplastic left-sided heart syndrome in a neonate. Clinical and hemodynamic conditions in our patient resemble the classical features of this syndrome except for a greater development of the ascending aorta and the left ventricular cavity, due to aortic insufficiency. A patch was unsuccessfully inserted at the aortic annulus to exclude the left ventricle from the circulation. In addition the Norwood operation was performed.     

Aortic media necrosis in Marfan's disease in young adults. Apropos of 5 surgically treated cases, with 3 survivals

Five cases of Marfan's syndrome with cardiovascular lesions are presented. Among these five patients, two with type I aortic dissection, one with true aneurysm of the ascending aorta and one with aortic regurgitation underwent composite grafting of the ascending aorta according to the Bentall technique. The fifth patient died preoperatively, due to extensive dissection of the transverse aorta. Marfan's syndrome is transmitted in an autosomal dominant manner. Fifty percent of the patients die at a mean age of 32 years, and 95 p. 100 of the deaths are caused by cardiovascular lesions. These lesions predominantly affect the left cardiac valves (aortic or mitral regurgitation) and the ascending aorta. Except in emergencies, replacement of the ascending aorta by a composite graft must be envisaged in subjects with Marfan's syndrome presenting with aortic regurgitation and dilatation of the aortic root.     

Left cervical aortic arch associated with multiple vascular anomalies

Cervical aortic arch is a rare anomaly occasionally associated with other cardiovascular abnormalities. We present a case of tortuous left cervical aortic arch associated with hypoplastic transverse arch, coarctation of the aorta, and right brachiocephalic arteries arising below the coarctation and stenotic origin of the left subclavian artery. These multiple anatomic anomalies, which are associated in our case, have not been described in a single patient previously.     

Double Aortic Arch with Aortic Atresia and Left-Sided Type B Interruption

Aortic valve atresia with interruption of the aortic arch is an extremely rare anomaly; only eleven cases of this anomaly have been reported to date. In the absence of additional sources of blood flow to the ascending aorta, aortic valve atresia with interruption of the aortic arch is fatal. We present, to the best of our knowledge, the first case of a live birth with aortic valve atresia and interrupted left aortic arch (type B) without evidence of an aorticopulmonary communication or ductal supply to the native ascending aorta. Instead, blood flow to the native aortic root was derived from a persistent right embryonic dorsal aorta.     

The Impact of Aortic Arch Geometry on Flow Dynamics Using a Simplified Approach with Magnetic Resonance Velocity Mapping

Background. We sought to determine, in vivo, the impact of aortic arch geometry on flow dynamics, which affects overall cardiovascular energetics and has implications for organ perfusion and Doppler flow calculations. Methods. Twenty‐seven patients (13 with left and 14 with right aortic arches) underwent magnetic resonance phase‐encoded velocity mapping in the ascending and descending aorta. The cross‐sectional area were divided into 4 equal quadrants aligned along the long axis of the aorta for analysis. Significance P < .05. Results. In the ascending aorta, there was a significantly higher total flow throughout the cardiac cycle in the posterior and leftward quadrant of right aortic arch than left aortic arch (P = .007) that was compensated for by significantly lower flow in anterior and rightward quadrant of right aortic arch than left aortic arch (P = .02). In the right aortic arch, maximum velocity (100 ± 14 cm/second) occurred in 7/9 patients in the right half while in left aortic arch, maximum velocity (107 ± 20 cm/second) occurred in 13/15 in the left half. In the descending aorta, whether left aortic arch or right aortic arch, the posterior half appeared to have greater flow than the anterior half. Conclusion. Right aortic arch geometry impacts flow dynamics in the ascending aorta whereas it is not altered in the descending aorta, where flow is predominantly in the posterior half. The sidedness of the aortic arch determined the location of maximum velocity. Alternatively, this also may suggest that hemodynamics could have played a role in the development of right aortic arch in certain individuals.     

Association of left ventricular hypertrophy and aortic dilation in patients with acute thoracic aortic dissection

This study was designed to evaluate the impact of left ventricular mass on aortic diameters in patients who presented with acute thoracic aortic dissection where aortic dilation is common. Retrospective review of transthoracic and transesophageal echocardiograms was conducted for 63 patients treated for acute thoracic aortic dissection and for 16 normal subjects who were comparable for gender prevalence, age, heart rate, and blood pressure. The diameter of the aortic root was measured by transthoracic echocardiography. Diameters of the ascending aorta, and of the aorta at locations of 25, 30, and 35 cm from the dental arch were measured by transesophageal echocardiography. The findings indicated that all aortic diameters were significantly larger in patients with aortic dissection. Patients with aortic dissection also presented with greater left ventricular mass indices (p<0.00001) than normal subjects. Fractional shortening and left atrial diameter measurements obtained in patients with aortic dissection were similar to those obtained in the control group. Overall, the left ventricular mass index exhibited univariate relationships with aortic root diameter (r=0.27, p<0.02) and aortic diameters at 25 cm (r=0.51, p<0.00001), 30 cm (r=0.58, p<0.00001), and 35 cm (r=0.55, p<0.00001) distal to the arch but not with the diameter of the ascending aorta. After adjusting for gender, body mass index, history of hypertension and aortic dissection extent (Stanford types) by separate multivariate models, the authors found that the left ventricular mass index was independently associated with aortic diameters at 25 cm (beta=0.32, p<0.001), 30 cm (beta=0.38, p<0.0001), and 35 cm (beta=0.34, p < 0.0005) distal to the arch. They conclude that left ventricular mass is independently associated with aortic arch and descending aorta diameters in patients with acute thoracic aortic dissection. Left ventricular hypertrophy may be considered a risk factor for aortic enlargement and subsequent dissection.