Clinical features of aortic arch anomaly with malalignment ventricular septal defect

Aberrant Subclavian Artery in Interrupted Aortic Arch with Severe Aortic Outlet Obstruction: Cerebral Blood Flow as a Possible Determinant of Embryonic Cardiovascular Development?

Aberrant subclavian artery (ASCA) is frequently observed in interrupted aortic arch (IAA) with aortic/subaortic obstruction. Developmental significance of ASCA in IAA in utero remains elusive. Newborns with prenatally diagnosed isolated IAA under continuous prostaglandin E1 infusion were studied. Cross-sectional areas of aortic valve opening (AVOCSA) and patent ductus arteriosus (PDACSA) were represented by echocardiographic measurement of (diameter)2 indexed by body surface area (m2). Types of IAA and presence of ASCA were examined in relation to sizes of AVOCSA and PDACSA. Twenty-four newborns with IAA (six type A and 18 type B) were reviewed. Male dominance was seen in type B (male 72%). Twenty-three patients had left aortic arch. No type A patients had ASCA, but 50% of type B had ASCA; AVOCSA was significantly smaller in type B than in type A (p = 0.003). In type B, PDACSA was significantly larger in those with ASCA than without (p = 0.003), but AVOCSA exhibited no significant size difference between these two subgroups. Chromosome 22q11 deletion was only seen in type B (56%) and showed no significant correlation with the presence of ASCA. In type B IAA, the presence of ASCA was associated with larger PDACSA, suggesting an adaptive enlargement of the ductus arteriosus and ASCA in response to reduced antegrade flow across small AVOCSA, which may be augmenting cerebral blood flow. Preservation of cerebral blood flow may be another important determinant affecting embryonic cardiovascular development.

Growth of left ventricular outflow tract and predictors of future re-intervention after repair for ventricular septal defect and aortic arch obstruction

Ventricular septal defect and aortic arch obstruction are usually associated with a narrow left ventricular outflow tract. The aim of the present study was to analyse the growth and predictors of future obstruction of the left ventricular outflow tract after surgical repair.

METHODS

We carried out a retrospective review of patients who underwent repair for ventricular septal defect and aortic arch obstruction - coarctation or interrupted aortic arch - between July, 2002 and June, 2013. Echocardiographic data were reviewed, and the need for re-intervention was evaluated.

RESULTS

A total of 89 patients were included in this study. A significant left ventricular outflow tract growth was noticed after surgical repair. Preoperatively, the mean left ventricular outflow tract Z-score was -1.46±1 (range -5.5 to 1.1) and increased to a mean value of -0.7±1.3 (range -2.7 to 3.2) at last follow-up (p=0.0001), demonstrating relevant growth of the left ventricular outflow tract after repair for ventricular septal defect and aortic arch obstruction. After primary repair, 11 patients (12.3%) required re-intervention with surgical repair for left ventricular outflow tract obstruction after a mean period of 36±21 months. There were no significant differences in age, weight, and indexed aortic valve and left ventricular outflow tract measurements between those who developed obstruction and those who did not.

CONCLUSION

Significant left ventricular outflow tract growth is expected after repair of ventricular septal defect and aortic arch obstruction. Small aortic valve and left ventricular outflow tract at diagnosis are not risk factors to predict the need for surgical re-intervention for left ventricular outflow tract obstruction in future.

Predictors of left ventricular outflow obstruction following single-stage repair of interrupted aortic arch and ventricular septal defect

This study looked at echocardiographic predictors of left ventricular outflow obstruction after primary neonatal repair of interrupted aortic arch and ventricular septal defect. Results of this study indicate that the only significant independent predictor of left ventricular outflow obstruction is aortic valve diameter; all patients with an aortic valve diameter <4.5 mm (Z score <-5) subsequently developed obstruction, whereas patients with annuli >4.5 mm (Z score >-5) remained free from obstruction.

Mid- to long-term results of the two-stage approach for type B interrupted aortic arch and ventricular septal defect

BACKGROUND

Type B interrupted aortic arch with ventricular septal defect is a complex congenital heart defect that may have associated left ventricular outflow tract obstruction. Surgical management has evolved from a two-stage approach to the currently favored single-stage approach. The following data summarize our experience with the two-stage approach over a 15-year period.

METHODS

Between 1980 and 1995, 27 consecutive patients with type B interrupted aortic arch and ventricular septal defect underwent surgical management using the two-stage approach. There were 15 girls and 12 boys; 21 patients had the DiGeorge syndrome.

RESULTS

Stage I was performed at a median age of 4 days. Twenty-six (96%) of 27 patients survived first-stage palliation. One patient survived stage I palliation but died before undergoing stage II. Twenty-five patients underwent second-stage repair at a median age of 6 weeks (range, 1 to 46 weeks). There were 2 early deaths and 1 late death. Actuarial analysis demonstrates 1- and 5-year survival rates of 85% and 81%, respectively. Twenty-two survivors have been followed up for an average of 8 +/- 2 years. Freedom from reoperation for arch graft enlargement has been 86% at 3 years and 55% at 5 years. Freedom from reoperation for left ventricular outflow tract obstruction has been 82% at both 3 and 5 years.

CONCLUSIONS

The two-stage approach can achieve good mid- to long-term palliation of patients with type B interrupted aortic arch and ventricular septal defect. These results should provide a reference from which to gauge the long-term success of the single-stage approach.

The left ventricular outflow tract in atrioventricular septal defect revisited: surgical considerations regarding preservation of aortic valve integrity in the perspective of anatomic observations

OBJECTIVE

The anatomy of the left ventricular outflow tract in hearts with atrioventricular septal defect has been widely investigated, but controversies remain regarding detailed aspects of left ventricular outflow tract anatomy in the perspective of operative techniques to either prevent or relieve outflow tract obstruction.

METHODS

We investigated 29 postmortem hearts with an atrioventricular septal defect. Measurements were taken of the circumferences and of the widths of the components that make up the outflow tract, that is, the interventricular septum, the superior bridging leaflet, the left ventricular free wall, and the length of the tendinous cords.

RESULTS

The circumference of the left ventricular outflow tract immediately underneath the aortic valve was not different from that at the middle part of the outflow tract. Hearts with the partial type defect, characterized by separate atrioventricular orifices, had a smaller outflow tract than those with the complete variety. Although the anatomic constituents that contribute to left ventricular outflow tract obstruction are complex, this study showed that a reduced width of the interventricular septum was most intimately related to narrowing immediately underneath the aortic valve. Obstruction at the middle part of the left ventricular outflow tract was largely caused by reduced width of the interventricular septum together with short tendinous cords.

CONCLUSIONS

On the basis of these observations, we recommend detailed investigation of the anatomy of the left ventricular outflow tract immediately underneath the aortic valve, before surgical attempts to relieve outflow tract obstruction, because in some procedures the integrity of the aortic valve will be at stake.

Dilation mechanism, causes of restenosis and stenting in balloon coarctation angioplasty

This review focuses on the individual dilation mechanism, the possible cause of restenosis after balloon angioplasty and the clinical application of a stent in coarctation of the aorta. Balloon angioplasty is still not the first choice of therapy in neonates with native coarctation because of the potential risk of aortic disruption, the high incidence of restenosis and the satisfactory results of surgical coarctectomy. Intravascular ultrasound imaging provides the individual mechanism of aortic dilation by balloon, and this will be a new modality for assessing the relationship between restenosis and aortic luminal morphology after balloon dilation. Although the cause of restenosis after balloon angioplasty remains uncertain, it may be due to a combination of elastic recoil by ductal tissue constriction, intimal hyperplasia and arterial remodelling. A stent could be an effective alternative to conventional balloon angioplasty in native coarctation of the aorta, preventing ductal tissue constriction. However, the problematic relationship between patient growth and relative stenosis of the stent should be clarified before clinical application of a stent for this disease.

Posterior deviation of left ventricular outflow tract septal components without ventricular septal defect

OBJECTIVE

To describe 11 patients with narrowing of the left ventricular outflow tract caused by angular posterior deviation of both the outlet septum and the upper part of trabecular septum, which was diagnosed by cross sectional echocardiography in all and confirmed by angiocardiography in seven.

RESULTS

Four patients had a subaortic systolic pressure gradient ranging from 23 to 70 mm Hg by Doppler echocardiography; cardiac catheterisation showed a significant (60 and 104 mm Hg) systolic pressure gradient in two. In four cases aortic regurgitation and two tricuspid pouches were shown by Doppler echocardiography, angiocardiography, or both. Four cases had a ridge at the angulation point on echocardiographic examination. Three patients were operated on for systolic pressure gradients of the left ventricular outflow tract and one for severe aortic regurgitation. There was proliferation of collagen-rich fibrous tissue in the subendocardial region on histopathological examination of the myectomy material. A ventricular septal defect had been diagnosed previously by contrast echocardiography in one patient; thus ventricular septal defects may close spontaneously over a period of time including fetal life. A subaortic ridge was detected in one patient at follow up.

CONCLUSIONS

Deviation of the outlet and trabecular septa should be considered as a cause of ventricular outflow tract obstruction even when no ventricular septal defect is present.

One-stage repair of interrupted aortic arch, ventricular septal defect, and subaortic obstruction in the neonate: a novel approach

BACKGROUND

One-stage repair of interrupted aortic arch, ventricular septal defect, and severe subaortic stenosis represents a surgical challenge. Techniques that use extracardiac conduits to bypass the subaortic area or involve transaortic or transatrial resection of the conal septum have shown limitations and have failed to reduce the high mortality rate associated with subaortic obstruction.

METHODS AND RESULTS

A new operative approach was used in nine neonates (2.1 to 3.9 kg) who underwent one-stage repair of interrupted aortic arch (type B, eight patients; type C, one patient), ventricular septal defect, and severe subaortic stenosis. All patients had severe subaortic stenosis according to preoperative echocardiography (mean ratio of subaortic to descending aortic diameter, 0.63 +/- 0.08). With a transpulmonary (seven patients) or transatrial (two patients) approach and without resection of the conal septum, the ventricular septal patch was placed on the left side of the septum to deflect the conal septum anteriorly and away from the subaortic area. There were no early or late deaths. Median intensive care unit and hospital stays were 17 days (6 to 47 days) and 21 days (10 to 55 days), respectively. On follow-up echocardiography (1 to 29 months, median 12 months), no patients had significant residual subaortic obstruction and one patient had mild residual arch obstruction (20 mm Hg). Growth of the subaortic region was demonstrated in all patients (mean ratio of subaortic to descending aortic diameter, 1.20 +/- 0.10; < 0.001).

CONCLUSIONS

Relief of severe subaortic stenosis during one-stage neonatal repair of aortic arch interruption and ventricular septal defect can be accomplished successfully without resection of the conal septum.

Morphology of left ventricular outflow tract structures in patients with subaortic stenosis and a ventricular septal defect

OBJECTIVE

To compare the incidence and prognosis of subaortic stenosis associated with a ventricular septal defect and to define the morphological basis of subaortic stenosis.

DESIGN

Presentation and follow up data on 202 patients with subaortic stenosis seen at the Royal Liverpool Children's Hospital between 1 January 1960 and 31 December 1991 were reviewed. Survivors were traced to assess their current clinical state. Necropsy specimens of 291 patients with lesions associated with subaortic stenosis were also examined.

RESULTS

In the clinical study; 65 (32.1%) of the 202 patients with subaortic stenosis had a ventricular septal defect (excluding an atrioventricular septal defect). 32 of these patients had a short segment (fibromuscular) subaortic stenosis. 33 had subaortic stenosis produced by deviation of muscular components of the outflow tracts. In 17 patients (51.5%) this was caused by posterior deviation or extension of structures into the left ventricular outflow tract, resulting in obstruction above the ventricular septal defect. In the other 16 patients (48.5%) there was over-riding of the aorta with concordant ventriculoarterial connections, (without compromise to right ventricular outflow) producing subaortic stenosis below the ventricular septal defect. Additional fibrous obstruction occurred in 39% of the patients with deviated structures. The age at presentation was lower (P < 0.01) in patients with deviated structures (median (range) 0.4 (0 to 9.2) months) than in those with short segment obstruction (median (range) 4.2 (0 to 84.9) months). The incidence of aortic arch obstruction was higher (P < 0.002) in patients with deviated structures than in those with short segment obstruction (38%). In the morphological study 35 pathological specimens showed obstructive muscular structures in the left ventricular outflow tract either above or below the ventricular septal defect. 16 had either posterior deviation of the outlet septum or extension of the right ventriculoinfundibular fold, or both of these together into the left ventricle. 19 had anterior deviation of the outlet septum into the right ventricle with overriding of the aorta (without compromise to right ventricular outflow). The earliest age at which additional fibrous obstruction was seen was 9 months. The aortic valve circumference was small in 18% of specimens.

FOLLOW UP

The median (range) duration of follow up in survivors from the clinical study was 6.6 (1 to 25.7) years. 16 patients with deviated musculature (49%) and 16 with short segment fibromuscular stenosis (50%) underwent operation for subaortic stenosis. Patients with deviated structures were younger at operation than those with short segment stenosis (P < 0.005). Patients with posterior deviation or extension of structures into the left ventricular outflow tract underwent operation for subaortic stenosis more frequently (P < 0.05) than those with anterior deviation of the outlet septum and aortic override. The ventricular septal defect required surgical closure more frequently (P < 0.005) in patients with deviation (93.9%) than in those with short segment obstruction (21.9%). There was no significant difference in the mortality between patients with deviation (27%) and those with short segment obstruction (12%).

CONCLUSIONS

32% of patients in the clinical study with subaortic stenosis had a ventricular septal defect. Only 51% of these had obstructive and deviated muscular structures in the left ventricular outflow tract. These patients had a significantly higher incidence of aortic arch obstruction and required surgery for subaortic stenosis at a younger age than those with short segment obstruction. The ventricular septal defect also required surgical closure more frequently in those patients with deviation. The morphological study defined the two sites of obstruction. The presence or absence and type of deviation should be clearly defined in all patients with a ventricular septal defect,

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.