Interrupted aortic arch--anatomical features of surgical significance

Single-Stage Repair of Interrupted Aortic Arch With Aortopulmonary Window and Bovine-Type Aortic Arch Complicated by Left Subclavian Artery Origin Stenosis-A Case Report

An aortopulmonary window is known to be associated in 5% of interrupted aortic arch cases. The combination of these lesions with a bovine-type aortic arch is much more uncommon. We report its embryological explanation and successful single-stage surgical repair in a three-month-old infant.

A new anatomic approach of the ventricular septal defect in the interruption of the aortic arch

The aim of this study was to analyse the anatomy of the ventricular septal defect (VSD) in heart specimens with interruption of the aortic arch (IAA) in order to explore the hypothesis of different embryologic mechanisms for the different anatomic types of IAA. We examined 42 human heart specimens, 25 with IAA as the main disease with concordant atrioventricular and ventriculo-arterial connections and two distinct great arteries, and 17 hearts with IAA associated with other malformations [six common arterial trunk (CAT), five double-outlet right ventricle (DORV), three transposition of the great arteries (TGA), three atrioventricular septal defect (AVSD)]. The interruption was classified according to Celoria and Patton. We focused on the anatomy of the VSD viewed from the right ventricular side. There were 15 IAA type A, 27 type B, no type C. The VSD in IAA type B was always an outlet VSD, located between the two limbs of the septal band, with posterior malalignment of the outlet septum in hearts with concordant ventriculo-arterial connections, without any fibrous tricuspid-aortic continuity. In addition, the aortic arch was always completely absent. Conversely, the VSD in IAA type A could be of any type (outlet in six, muscular in four, central perimembranous in two, inlet in three) and the aortic arch was either atretic or absent. In addition, IAA type B, when found in the setting of another anomaly, was always associated with neural crest-related anomalies (CAT and DORV), whereas IAA type A was found in association with anomalies not related to the neural crest (TGA and AVSD). These results reinforce the hypothesis that different pathogenic mechanisms are responsible for the two types of IAA, and the inclusion of IAA type B in the group of neural crest defects. Conversely, IAA type A could be due to overlapping mechanisms: flow-related defect (coarctation-like) and neural crest contribution.

Surgical Considerations in Interrupted Aortic Arch

Interrupted aortic arch (IAA) is a rare congenital anomaly with several anatomical variants and is often associated with other intracardiac and/or extracardiac congenital anomalies. Historically, associated with high early mortality, outcomes for this anomaly have improved in recent eras with advances in perioperative and anesthesia management and refinements in surgical technique. This review provides a description of surgical anatomy, anatomical classifications, and associated congenital lesions as well as an examination of the perioperative and surgical management of IAA in the contemporary surgical era.

An unusual case of interrupted cervical aortic arch associated with long segment coarctation of the descending thoracic aorta

Interrupted aortic arch is a rare congenital anomaly in newborns and infants and is commonly associated with other cardiovascular anomalies. Here, we report an unusual case of type A interrupted cervical aortic arch associated with long segment coarctation of the descending thoracic aorta. Patent ductus arteriosus reconstituted the descending thoracic aorta. Proximal segments of the left common carotid and left subclavian arteries were atretic. Echocardiography-gated multidetector CT angiography not only identified the type of aortic arch interruption in the neonate but also delineated the exact anatomical details.

Results of primary and two-stage repair of interrupted aortic arch

OBJECTIVE

Early results of primary and two-stage repair of interrupted aortic arch have improved. Experience with different surgical approaches should be analysed and compared.

METHODS

Forty neonates and infants with interrupted aortic arch underwent primary repair (19 patients) or palliative operation (21 patients). Twenty (50%) patients were followed-up for 5.1+/-4.3 years. All patients were regularly examined with the aim of determining clinical development, presence of residual lesions or complications and need for re-intervention. Aortic arch and the left ventricular outflow tract growth were assessed by echocardiographic examination. Data from hospital and outpatient department records were analysed.

RESULTS

The early mortality was 61.9% after palliative operations and 36.8% after the primary repair. Presence of complications (P < 0.001), earlier year of surgery (P < 0.01), bad clinical condition and acidosis (P < 0.05) represented statistically significant risk factors for death in the whole series. In seven (87.5%) out of eight early survivors, after the initial palliative operation, closure of ventricular septal defect and debanding were done, and in three (37.5%) patients, re-operation for aortic arch obstruction was also required. Out of 12 patients, after the primary repair, one required early re-operation for persistent left ventricular outflow tract obstruction and two needed late re-intervention for left bronchus obstruction. In three (25%) patients, after the primary repair, left ventricular outflow tract obstruction with a maximal systolic pressure gradient higher than 30 mmHg developed. At present, all 20 early survivors are alive. Five patients, after palliative operation, are in NYHA class 1, but in three patients, who are in class III or IV, the outcome is influenced by severe complications. All patients after the primary repair are in class I or II.

CONCLUSIONS

Our experience confirmed better results after the primary repair of interrupted aortic arch, which was associated with lower mortality, prevalence of severe complications and need for re-intervention. Higher prevalence of subaortic stenosis after primary repair could be explained by patient selection early in our experience. We recommend the primary repair of interrupted aortic arch and associated heart lesions in neonates, however, in unfavourable conditions an individualised surgical approach with initial palliative surgery should be considered.

The surgical anatomy of the left ventricular outflow tract in hearts with ventricular septal defect and aortic arch obstruction

BACKGROUND

Profound understanding of the left ventricular outflow tract (LVOT) anatomy is crucial to improve surgical results in patients with aortic arch obstruction, ventricular septal defect, and subaortic stenosis.

METHODS

We studied the morphology of the LVOT in 32 postmortem hearts with aortic arch obstruction and a ventricular septal defect. In case of subaortic obstruction, the length of the subaortic muscular component was measured anteriorly and posteriorly within the left ventricle.

RESULTS

Seven of the 32 hearts had no subaortic stenosis. Nine had aortic override, which caused LVOT narrowing. Sixteen hearts contained a subaortic shelf, downstream to the ventricular septal defect, which deviated into the left ventricle in 15. In 10 of these the shelf was muscular; in 6 it was a fibrous ridge. In cases with a muscular shelf, the posterior part was significantly shorter than the anterior part (p < 0.004). In 9 hearts the LVOT was further narrowed because of the abnormal relationship between the mitral valve and the subaortic shelf.

CONCLUSIONS

The present study confirms the complexity of LVOT stenosis in aortic arch obstruction and ventricular septal defect and provides a better understanding of the options to achieve surgical relief.

Clinical implications and possible association of malposition of the branch pulmonary arteries with DiGeorge syndrome and microdeletion of chromosomal region 22q11

We describe a series of 10 patients with malposition of the branch pulmonary arteries (4 patients with crossing [crossed pulmonary arteries] and 6 patients without crossing), 2 of whom had a short main pulmonary artery segment that resulted in iatrogenic right pulmonary artery stenosis after pulmonary artery band placement. DiGeorge syndrome was seen in 5 patients and 4 had microscopic deletion of chromosomal region 22q11.

Interrupted aortic arch. Impact of subaortic stenosis on management and outcome

Interrupted aortic arch (IAA) is often related developmentally to subaortic obstruction (SAO). When severe, SAO must be addressed in surgical management of IAA. From 1990 to 1993, 25 neonates presented for initial surgical management of IAA complexes. Associated lesions were ventricular septal defect (VSD) with or without atrial septal defect (19 patients), truncus arteriosus (3 patients), tricuspid atresia with transposition of the great arteries (1 patient), aortic atresia with VSD (1 patient), and d-transposition of the great arteries with VSD (1 patient). Overall hospital mortality was 20% (five deaths). One death was related to sepsis and two to sudden hemodynamic decompensation (a 2-kg premature infant after arch repair and VSD closure and a neonate with IAA-truncus arteriosus after arch repair and truncus repair with aortic root replacement). Two deaths were related to low cardiac output in patients with severe subaortic narrowing (< 3 mm by two-dimensional echocardiography), which was not addressed surgically. Of 10 additional patients judged preoperatively to have severe SAO, 1 underwent resection of the infundibular septum together with VSD closure and arch reconstruction, and 9 underwent a modification of Norwood's operation with arch reconstruction and proximal pulmonary artery to aortic anastomosis (7 with systemic to pulmonary artery shunts and 2 with right ventricle to pulmonary artery outflow tract reconstruction). One patient died 2 months after surgery of staphylococcal sepsis. All 9 others were discharged well. Subaortic narrowing is a physiologically important element of IAA complexes. When SAO is severe, satisfactory initial palliation can be achieved by a modification of Norwood's operation.

The relationship of the outlet septum to the aortic outflow tract in hearts with interruption of the aortic arch

We examined 13 hearts with concordant atrioventricular and ventriculoarterial connections and interruption of the aortic arch to establish and describe the morphologic features of the outflow tracts in relation to axial deviation and malalignment of the outlet septum as opposed to overriding of the arterial valvular orifices. Interruption in all cases but one was between the left common carotid and left subclavian arteries; the other arch was interrupted at the isthmus. A patent arterial duct and ventricular septal defect were universally present. When its borders were viewed from the right ventricle, the ventricular septal defect was perimembranous in seven hearts, had exclusively muscular borders in four hearts, and was doubly committed and juxta-arterial in the remaining two hearts. Malalignment between the muscular ventricular septum and outlet septum, or a fibrous raphe, as judged when the heart was viewed in its short axis, was found in 12 of the hearts. Posterior and leftward axial deviation of the outlet septum in its long axis was found in 4 of the 12 hearts and also in one heart that did not have short-axis malalignment. Attachments of the leaflets of the pulmonary valve in both right and left ventricles, however, were present in only one of the specimens, this being a case with a doubly committed and juxta-arterial defect. These separate features of the outflow tract in hearts with interruption of the aortic arch, therefore, require thorough assessment when surgical management is planned. All these variable features can be assessed preoperatively by cross-sectional echocardiography, which should be directed toward defining the degree of development and alignment of the outlet septum, as well as the length of the subpulmonary infundibulum.

Echocardiographic predictors of left ventricular outflow tract obstruction after repair of interrupted aortic arch

OBJECTIVES

This study was designed to identify preoperative echocardiographic predictors of left ventricular outflow tract obstruction after repair of interrupted aortic arch and ventricular septal defect closure.

BACKGROUND

Left ventricular outflow tract obstruction becomes apparent in nearly 50% of patients after repair of interrupted aortic arch and ventricular septal defect closure but is seldom recognized preoperatively.

METHODS

We analyzed the preoperative echocardiograms of all patients with interrupted aortic arch who had postoperative echocardiographic or catheterization data available. Thirty-seven infants (aged 1 day to 10 months, median 5 days) were included. Off-line measurements were performed on hard copies of selected images. The cross-sectional area (indexed to body surface area) and diameters (indexed to the square root of body surface area) of the left ventricular outflow tract; ascending and descending aorta; ventricular septal defect; and mitral, aortic and pulmonary valves were compared with outcome by using analysis of variance. Outcome was classified according to development of postoperative left ventricular outflow tract Doppler gradient (Group 1 < or = 20 mm Hg, Group 2 > 20 mm Hg).

RESULTS

The cross-sectional area of the left ventricular outflow tract was significantly smaller in patients who did than in those who did not develop subaortic obstruction ([mean +/- SD] 0.64 +/- 0.25 vs. 1.7 +/- 1.01 cm2/m2, p < 0.004). Left ventricular outflow tract and aortic valve diameters and aortic valve area were not predictive of postoperative left ventricular outflow tract obstruction. Incidence of postoperative left ventricular outflow tract obstruction was lower (p < 0.03) in interrupted aortic arch type A (0 of 6) than in type B (15 of 31). The incidence of aberrant right subclavian artery was lower (p < 0.02) in Group 1 (6 of 22) than in Group 2 (10 of 15).

CONCLUSIONS

The preoperatively measured cross-sectional area of the left ventricular outflow tract is significantly smaller in patients with interrupted aortic arch who develop subaortic obstruction postoperatively, with a left ventricular outflow tract area < or = 0.7 cm2/m2 being a sensitive predictor. Aortic arch anatomy (i.e., type of interrupted aortic arch and presence of aberrant right subclavian artery) is also predictive of postoperative left ventricular outflow tract obstruction, possibly by influencing the volume of blood flow across the left ventricular outflow tract. These data should enable preoperative identification of infants who may require surgical relief of subaortic stenosis.

Coarctation and other obstructive aortic arch anomalies: their relationship to the ductus arteriosus

Forty-three specimens with an obstructive aortic arch anomaly, obtained from infants that had died under the age of one year, were studied to establish the relationship between the arch anomalies and the ductus arteriosus. All specimens were studied morphologically. Twenty of the 43 were also studied histologically. The morphological part of the study included measurements of all the segments of the aortic arch and establishment of the localisation of any associated coarctation. The specimens were divided according to the appearance of the isthmus. The isthmus was not present in 4, was atretic in 2, hypoplastic in 19 and had a normal diameter in 18 cases. In all cases, except 5 (2 with atresia and 3 with hypoplasia of the isthmus) there was an associated coarctation. The majority of the coarctations (28) was located preductally. All such preductal coarctations had ductal tissue in the obstructing ridge. There were 5 paraductal coarctations. Of these, two also had ductal tissue in the ridge. The distribution of the ductal tissue among the two types of coarctation suggested a spectrum of anomalies rather than two completely different entities. The patterns of the aortic arches appeared predictive for the type of coarctation present. The arches that tapered normally towards the isthmus either presented with a preductal coarctation (20 cases) or without a coarctation (3 cases). All 4 specimens in which the isthmus was lacking also had a preductal coarctation. The 5 paraductal coarctations were found in arches that showed a "reverse" pattern, tapering towards the brachiocephalic arteries. All the preductal coarctations contained ductal tissue whereas only 2 of the 5 paraductal coarctations had ductal tissue in the obstructing ridge. It is concluded that careful evaluation of all the segments of the aortic arch may be helpful in the clinical evaluation of infants with an obstructive aortic arch anomaly.

Total anatomic correction of interrupted aortic arch complex. Experience in 4 infants

In two cases of interrupted aortic arch (IAA) of type A, one associated with a ventricular septal defect (VSD) and one with an aortopulmonary window, and two of type B, both associated with a VSD, total anatomic repair was performed at respective ages of 6 months and 24, 8 and 3 days. All four operations were performed through a median sternotomy, using profound hypothermia and circulatory arrest. The repair included resection of the patent ductus arteriosus, direct end-to-side anastomosis of the descending to the ascending aorta and closure of the VSD or, in one case, of the aortopulmonary window. The two oldest infants (with type A IAA) survived. Reexamination two years postoperatively demonstrated good width of the aortic anastomosis with no gradient. In the child who had had an aortopulmonary window there was a proximal tight stenosis of the right pulmonary artery, which was corrected at reoperation. Total anatomic correction of IAA through an anterior approach is technically feasible and the aortic anastomosis seems to grow satisfactorily. The management of very sick neonates with IAA remains a great challenge.