Surgical Experience With Nine Cases of Obstructed Right Aortic Arch

Introduction

Surgical methods for coarctation repair continue to improve since its first description by Crafoord and Gross in 1945.^1,2 The first neonatal repair was attempted in 1953, and surgical outcomes have improved dramatically over the last few decades with significant advances in operative technique, anesthesia, and postoperative intensive care. ³ The majority of coarctation of the aorta occurs in a left aortic arch with an incidence of 5% to 8% of congenital heart disease.^4,5 Conversely, a right aortic arch occurs in 0.1% of the population, ⁵ and only 4% of those develop obstruction (coarctation, interrupted arch). ⁶ Surgical approach may vary depending on the degree of coarctation, associated arch hypoplasia, or other intracardiac defects that might require repair (ventricular septal defect [VSD], atrial septal defect [ASD], Tetralogy of Fallot [TOF]). Due to the rare nature of right aortic arch obstruction, there are few reports describing the optimal surgical technique and expected surgical outcomes.^6–9 We have reviewed our institutional experience over the last 30 years and described our tailored surgical approach.

Patients and Methods

After approval from The University of Alabama at Birmingham Institutional Review Board was obtained, patients were identified from a historical database of old operative reports and from the Society of Thoracic Surgeon's database for more contemporary patients. The surgical records of all patients with right aortic arch obstruction who underwent surgical repair from 1992 to 2022 were reviewed. Aortic arch obstruction was defined by echocardiogram or cross-sectional imaging (computed tomography angiography [CTA]), prostaglandin-dependent circulation, or a 20 mm Hg gradient by upper and lower extremity blood pressure (BP). Aortic arch hypoplasia was defined as proximal or distal arch hypoplasia. Proximal arch hypoplasia was defined as the portion of the arch just beyond the take-off of the innominate artery (in mirror image branching) or the first head vessel (with an aberrant left subclavian) being less than 50% the size of the ascending aorta. Distal arch hypoplasia was defined as the portion of the arch just before the take-off of the last arch vessel, being less than 50% the size of the ascending aorta. Interrupted aortic arch was confirmed by echocardiogram, and more recently CTA to further clarify the arch anatomy. Nine patients with right aortic arch obstruction who underwent surgical repair were identified and included in this study.

Results

Our patient cohort included nine patients. Patient characteristics and outcomes are presented in Table 1. Fifty-six percent (n = 5) of our cohort were male and 67% (n = 6) underwent surgical repair as neonates. Four patients (44%) had a genetic syndrome, one of these four patients had more than one genetic disorder (DiGeorge-2, heterotaxy-2, and vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal anomalies, and limb abnormalities (VACTERL)-1). Five patients (56%) were on prostaglandin infusion to maintain ductal patency prior to surgical repair. Preoperative echocardiogram was used in all patients (n = 9) to make a diagnosis of right aortic arch obstruction and CTA was utilized in four patients (44%) to further delineate anatomy and help with surgical planning (Figure 1).

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Figure 1.

CT scan 3D reconstruction of right aortic arch obstruction with a severely hypoplastic transverse arch. Abbreviations: CT, computed tomography; 3D, three-dimensional.

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Table 1.

Patient Characteristics and Outcomes for Patients Who Underwent Surgical Repair for Right-Sided Aortic Arch Obstruction From 1992 to 2022.

Pt	Age sex	Arch anatomy	PDA	DA	Associated cardiac anomalies	Other diagnoses	Surgical approach	Type of repair	1) Alive2) Arch Reintervention
1	3 d M	Circumflex aorta, discrete CoA, ALSCA,	L	L	VSD, PDA	None	Thoracotomy (L) & Sternotomy	GORE-TEX® tube graft, VSD closure	Unknown
2	1 w F	Hypoplastic aortic arch, proximal arch hypoplasia, CoA	R	R	Dextrocardia, situs inversus, DORV, L-TGA bilateral SVC	Heterotaxy	Sternotomy	Arch advancement, patch augmentation, PA band, atrial septectomy	1) Yes 2) No
3	2 w F	CoA, distal arch hypoplasia, MIB	R	R	Dextrocardia, situs inversus, L-TGA, VSD, ASD, PDA	None	Thoracotomy (R) & Sternotomy	EEEA, RSF, VSD closure, ASD closure	1) Yes 2) Yes, balloon dilation
4	2 w F	IAA, Type B, ALSCA	R	R	VSD, ASD	DiGeorge	Sternotomy	Arch advancement, VSD, ASD closure	1) Yes 2) No
5	2 w M	Hypoplastic arch, proximal arch hypoplasia, CoA, ALSCA	L	R	Vascular ring	Heterotaxy, VACTERL	Sternotomy	Arch advancement, division of vascular ring, division of ALSCA	1) Yes 2) No
6	2 w F	IAA, ARSCA, ALSCA	B/L	R	Vascular ring, Kommerell diverticulum, VSD, ASD	None	Sternotomy	Arch advancement, division of vascular ring, division of ARSCA, VSD & ASD closure	1) No 2) No
7	1 m M	CoA, distal arch hypoplasia, ALSCA	R	R	ASD, PDA	Spinal defects, absent corpus callosum	Thoracotomy (R)	EEEA, RSF	1) Yes 2) No
8	2 m M	Discrete CoA, MIB	R	R	TGA, TA, PS, VSD	None	Thoracotomy (R)	EEEA	1) Yes 2) No
9	3 m M	Discrete CoA, MIB	R	R	TOF, pulmonary atresia	DiGeorge, single kidney	Sternotomy	Arch advancement, TOF repair	1) Yes 2) No

Abbreviations: ALSCA, aberrant left subclavian artery; ARSCA, aberrant right subclavian artery; ASD, atrial septal defect; B/L, bilateral; CoA, coarctation of the aorta; DA, descending aorta; DORV, double outlet right ventricle; EEEA, extended end-to-end anastomosis; IAA, interrupted aortic arch; L, left; MIB, mirror-image branching; PA, pulmonary artery; PDA, patent ductus arteriosus; PS, pulmonary stenosis; Pt, patient; R, right; RAA, right aortic arch; RSF, right sublavian flap; SVC, superior vena cava; TA, tricuspid atresia; TGA, transposition of the great arteries; TOF, tetralogy of Fallot; VSD, ventricular septal defect.

Surgical approach included thoracotomy (n = 2), sternotomy (n = 5), or combination of both during the same surgical setting (n = 2). Primary extended end-to-end anastomosis (EEA) was performed when there was a discrete coarctation (n = 1, 11%), and reverse subclavian flap was utilized in patients who had evidence of distal arch hypoplasia (n = 2, 22%). One patient with a circumflex aorta (right aortic arch with left descending aorta) underwent a GORE-TEX® tube graft for reconstruction given the significant area of long-segment coarctation. The graft was 10 mm and the aorta was not uncrossed, unfortunately, this patient was in our early era so there were no postoperative images and was lost to follow-up. The remaining five patients (56%) underwent aortic arch advancement using deep hypothermic circulatory arrest. We chose to use Photofix™ pericardium in one of these patients for anterior patch augmentation in order to help relieve undue tension and adequately augment the aortic arch. Antegrade cerebral perfusion was utilized in three of the five patients (60%) who required arch advancement. The remaining two patients (40%) had aortic arch advancement under a brief period of circulatory arrest. For the entire cohort, the mean cardiopulmonary bypass time was 112 min (range 45-176 min); ascending aortic cross clamp 52 min (range 18-90 min); ACP 23 min (range 16-32 min); and deep hypothermic circulatory arrest 14 min (range 12-16 min). For those patients with isolated coarctations repaired via thoracotomy the mean cross clamp time was 18 min (range 10-26 min). Associated defects repaired at the time of sternotomy included VSD (n = 2), division of vascular ring (n = 2), division of aberrant subclavian (n = 2), and TOF (n = 1) (Table 1).

Freedom from reintervention on the reconstructed arch was 89% for our cohort (Figure 2). One patient (11%) required reintervention because of a recurrent coarctation at the anastomotic site. This patient originally underwent a reverse subclavian flap and came back with recurrent coarctation three months postoperatively. The gradient was completely relieved with balloon angioplasty, and no further intervention has been required. All patients were discharged in good condition with no 30-day mortality. There was one late death (11%) and one patient lost to follow-up with a mean follow-up period of 10.5 years. The patient who died had a complete heart block at the initial operation and developed progressive cardiomyopathy requiring a heart transplant. Following discharge, the patient suffered an acute intestinal volvulus six months after transplantation and died.

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Figure 2.

Kaplan-Meier analysis of freedom from reintervention following repair of right-sided arch obstruction.

Last available follow-up data (n = 7, 78%) show all patients are without antihypertensive medications, and there is no evidence of recurrent coarctation by echocardiogram. Although we do not routinely image patients to evaluate for airway compression, no bronchial issues have been reported to date. No patient has a significant arm-to-leg BP gradient and all are asymptomatic from a functional standpoint without exercise limitations.

Comment

Right aortic arch obstruction is a rare morphologic finding that can be quite challenging to surgically manage. There have been very few reports describing the optimal approach for managing neonates, infants, and children with right aortic arch obstruction given its rare association.^6‐9 We present our institutional experience over 30 years with a total of nine patients who had undergone surgical correction for right aortic arch obstruction. Our series reflects on the evolution of surgical management for right aortic arch obstruction and how our surgical strategy has changed over the last few decades. Two patients in our series underwent a reverse subclavian flap procedure to address distal arch hypoplasia. One of these patients required balloon angioplasty for recurrent coarctation likely due to residual ductal tissue near the reconstructed subclavian flap. Our institution no longer performs the reverse subclavian flap procedure because in our opinion it is more difficult to completely remove all ductal tissue with this technique. This could potentially lead to increased rates of recoarctation. Although our numbers are too small to make definitive conclusions, we believe that aggressively removing all ductal tissue can be an important surgical principle in decreasing the chance of recurrent coarctation in these patients. Therefore, it is our preference for discrete coarctation with or without distal arch hypoplasia, to perform a thoracotomy with resection and extended EEA. This allows aggressive removal of all ductal tissue and appropriate augmentation of the distal arch when necessary. This has yielded excellent results with low reintervention.

In patients with intracardiac defects in need of repair, with associated right aortic arch obstruction, we aggressively pursue a single-stage primary repair as demonstrated in Table 1. There were two patients who underwent a thoracotomy to address the coarctation followed by a sternotomy to address intracardiac defects in the same operative setting. This occurred in the earlier era of our series and would no longer be our surgical preference. Nationally, staged repair has fallen out of favor as outcomes for single-stage primary repair continue to improve for neonates and small infants. There were 5 (56%) patients in our cohort who underwent aortic arch advancement and simultaneous repair of all intracardiac defects via sternotomy. This is our preferred surgical approach to manage arch obstruction with intracardiac pathology regardless of a right or left arch.

A concern that some institutions have regarding arch reconstruction in patients with right aortic arches is bronchial compression due to the higher take-off of the right main stem bronchus. ¹² This has not been an issue in any of our patients who underwent aortic arch reconstruction by advancement technique. Extensive mobilization of the descending and ascending aorta allows for adequate length for reconstruction. Surgical exposure and operative setup for right aortic arch advancement tends to be similar to left-sided arches, but there is often a need to divide an anomalous left subclavian artery in order to achieve enough mobilization of the descending aorta. This tends to free up the descending aorta substantially and allows it to freely move up to the undersurface of the transverse arch. If there is still too much tension, we usually augment the anterior portion of the reconstructed aortic arch with a piece of Photofix™ pericardium.

Over the last 15 years, we, as an institution, have become more aggressive about obtaining cross-sectional imaging for all patients with aortic arch obstruction. Important additional information can be gained from a high-quality CTA to help surgical planning. In recent years, CTAs have become routine for all patients with right aortic arch obstruction and are being more frequently used for patients with left arch obstruction. Although in our early patients, CTA was not used and many of our patients had good outcomes, we believe that CTA provides a more precise transverse arch measurement as well as unmasking any abnormal aortic arch branching patterns and is an invaluable tool to help guide surgeons in their operative planning.

An extremely rare anomaly is that of a circumflex aorta where the right aortic arch crosses midline posteriorly behind the esophagus and descends on the left side of the spine. Early on in this series, we had one patient who required a GORE-TEX® tube graft to reconstruct the circumflex aortic arch and long segment coarctation. Currently, our strategy to surgically manage a circumflex aorta associated with arch obstruction (coarctation or hypoplasia) is with aortic uncrossing and arch advancement, which has been previously described. ⁹

In summary, right aortic arch obstruction is a rare entity. The optimal surgical approach should be tailored to underlying anatomy and associated intracardiac defects. Sternotomy with single-stage primary repair is safe, effective, and our preferred surgical approach for patients with right aortic arch obstruction and associated intracardiac pathology. As opposed to patients with left arch obstruction where echocardiogram is often the only necessary diagnostic modality, routine CTA in right aortic arch obstruction may provide valuable information to help with surgical planning in these rare cases.