Aortic Arch Repair via Median Sternotomy (Surgeon’s View)

Aortic arch repair through median sternotomy is a comprehensive operative strategy for neonates and infants with coarctation of the aorta when the obstruction extends beyond a discrete juxtaductal narrowing and involves the transverse arch, distal arch, isthmus, or proximal descending aorta. The central concept is that neonatal arch obstruction is frequently a regional disease of the arch, not simply a focal coarctation shelf. Durable repair therefore requires complete exposure of the arch and descending aorta, excision of ductal and coarctation tissue, relief of transverse arch hypoplasia, and creation of a broad, tension-free, growth-capable aortic pathway.

Recent comparative and single-center series support the safety and durability of median sternotomy for neonatal and infant arch repair, particularly when transverse arch hypoplasia is present or when intracardiac lesions require concomitant repair [1–5]. In contemporary series, early mortality is low, recurrent arch obstruction requiring reintervention is generally reported in the range of approximately 6–10%, and late freedom from reintervention is favorable when the repair adequately addresses the full arch anatomy [1,3–5].

1. Surgical Indication and Anatomical Target

Median sternotomy is most relevant when coarctation is associated with:

1. Hypoplastic transverse arch
2. Distal arch and isthmus hypoplasia
3. Long-segment arch narrowing
4. A large ductus arteriosus obscuring the distal arch
5. Associated intracardiac lesions requiring cardiopulmonary bypass
• Ventricular septal defect
• Atrial septal defect
• Atrioventricular septal defect
• Complex biventricular lesions
• Single-ventricle lesions requiring staged reconstruction

The decision between left thoracotomy and median sternotomy should be individualized according to the extent of arch hypoplasia, the relationship of the coarctation to the arch branches, associated intracardiac anatomy, and the need for cardiopulmonary bypass [1,6,7]. A left thoracotomy may be adequate for isolated coarctation with limited isthmic involvement, but it can be insufficient when the proximal transverse arch is significantly hypoplastic. In such cases, median sternotomy provides superior access to the ascending aorta, transverse arch, arch branches, ductus, and descending thoracic aorta.

The operative goal is not simply to “cut out the coarctation.” The objective is to reconstruct the entire narrowed segment so that flow from the ascending aorta into the descending aorta is smooth, non-obstructed, and anatomically durable.

2. Operative Exposure

2.1 Median Sternotomy

The operation begins through a median sternotomy. This provides direct access to the ascending aorta, innominate artery, transverse arch, main pulmonary artery, ductus arteriosus, and right atrium.

After thymic mobilization or partial thymectomy, the surgeon identifies the major vascular structures:

1. Ascending aorta
2. Innominate artery
3. Left common carotid artery
4. Left subclavian artery
5. Transverse and distal aortic arch
6. Patent ductus arteriosus
7. Main and branch pulmonary arteries
8. Descending thoracic aorta

This approach is particularly useful because it permits simultaneous control of perfusion, ductal flow, and arch geometry. Historical and contemporary reports describe the midline approach as a versatile strategy when arch reconstruction must extend beyond the juxtaductal segment or when intracardiac repair is required [6,7].

2.2 Mobilization of the Great Vessels

The arch vessels, ductus, and descending aorta must be mobilized sufficiently to permit a tension-free reconstruction. Inadequate mobilization is a major technical cause of residual narrowing, anastomotic tension, and late recoarctation.

Key technical principles include:

1. Mobilize the arch branches enough to permit safe clamping and reconstruction.
2. Divide ductal attachments to free the distal arch and descending aorta.
3. Mobilize the descending thoracic aorta sufficiently to reach the arch without traction.
4. Avoid injury to the recurrent laryngeal nerve region near the ductal arch.
5. Preserve tissue quality and avoid excessive adventitial trauma.

The descending aorta should not be forced upward to meet the arch. A durable repair depends on the descending aorta reaching the reconstructed arch naturally after complete mobilization.

3. Cannulation Strategy

3.1 Innominate Artery Graft Cannulation

A commonly used strategy is to sew a small graft to the innominate artery and use this graft for arterial cannulation. This provides stable systemic inflow for cardiopulmonary bypass and allows controlled transition to selective antegrade cerebral perfusion during the arch reconstruction.

Advantages include:

1. Stable arterial inflow away from the small neonatal ascending aorta
2. Improved operative exposure during arch reconstruction
3. Controlled cerebral perfusion through the innominate artery
4. Reduced manipulation of the ascending aorta
5. A practical route for perfusion during arch opening

This cannulation concept is widely used in neonatal arch reconstruction, especially when the arch will be opened under cerebral perfusion or circulatory arrest strategies [8].

3.2 Venous Cannulation

Venous return is typically established through right atrial cannulation. In isolated arch repair, single venous cannulation may be sufficient. When intracardiac repair is required, bicaval cannulation may be selected. The cannulation plan should reflect the total operative strategy, not only the arch repair.

4. Cardiopulmonary Bypass and Cerebral Protection

Cardiopulmonary bypass permits controlled systemic perfusion, cooling, ductal division, and arch reconstruction. Perfusion strategies vary by institution and include deep hypothermic circulatory arrest, selective antegrade cerebral perfusion, or hybrid strategies. Contemporary discussion emphasizes that cerebral protection is not defined by a single technique alone, but by the integration of flow, temperature, hematocrit, pressure, metabolic strategy, and monitoring [8].

4.1 Selective Antegrade Cerebral Perfusion

Selective antegrade cerebral perfusion allows oxygenated blood to be delivered to the brain, usually through the innominate artery, while the arch is opened. The major rationale is to reduce or avoid total circulatory arrest while maintaining a controlled operative field.

Important monitoring parameters include:

1. Cerebral near-infrared spectroscopy
2. Arterial pressure
3. Perfusion flow rate
4. Temperature
5. Acid-base management
6. Hematocrit
7. Lactate trend and systemic perfusion markers

The available literature supports the feasibility of selective antegrade cerebral perfusion, but comparative outcome data remain limited, and optimal lower-body perfusion strategies continue to evolve [8].

5. Ductal Control and Pulmonary Blood Flow Management

5.1 PDA Ligation

In neonatal coarctation and arch hypoplasia, the ductus arteriosus often provides critical lower-body perfusion before surgery. Once cardiopulmonary bypass is established, the ductus can be ligated to control pulmonary runoff and separate the systemic and pulmonary circulations.

Ductal control is essential for:

1. Hemodynamic stability during bypass
2. Reduction of pulmonary overcirculation
3. Improved visualization of the distal arch
4. Preparation for complete ductal tissue excision

5.2 PDA Division

Division of the ductus is a critical exposure maneuver. The ductus frequently tethers the distal arch and proximal descending aorta. After division, the descending aorta can be mobilized more completely, allowing a more favorable reconstruction.

PDA division improves:

1. Exposure of the distal arch
2. Mobilization of the descending aorta
3. Access to ductal tissue
4. Anastomotic geometry
5. Tension-free arch reconstruction

6. Coarctectomy and Ductal Tissue Excision

Complete excision of coarctation and ductal tissue is fundamental. Residual ductal tissue can constrict after repair and contribute to recurrent obstruction. This is particularly important in neonates, where ductal tissue may extend into the juxtaductal aorta, isthmus, and proximal descending aorta.

The surgeon must distinguish:

1. True aortic tissue
2. Ductal tissue
3. Coarctation shelf
4. Hypoplastic isthmus
5. Proximal descending aortic tissue

A durable repair requires an anastomosis constructed from healthy aortic tissue. Incomplete removal of ductal tissue may leave a biologic substrate for restenosis.

7. Arch Reconstruction Strategy

Several reconstructive strategies are described for neonatal and infant arch obstruction:

1. Extended end-to-end anastomosis
2. Extended end-to-side anastomosis
3. Arch advancement
4. Patch augmentation
5. Homograft patch aortoplasty
6. Autologous tissue-based arch reconstruction

The optimal technique depends on the length and location of hypoplasia, tissue quality, branch vessel anatomy, size discrepancy between the arch and descending aorta, and the presence of associated intracardiac lesions.

Median sternotomy facilitates direct treatment of transverse arch hypoplasia. In a series of neonates and infants undergoing arch augmentation via sternotomy, most repairs used homograft patch aortoplasty, with no mortality and a reported 10% reintervention rate for recurrent distal obstruction [3]. Another contemporary series of homograft patch arch repair reported no 30-day mortality, low neurologic adverse events, and a reintervention rate of approximately 9% [4].

8. Arch Aortotomy

Under cerebral protection, the aortic arch is opened. The aortotomy must be designed to treat the entire narrowed segment. A limited incision may leave residual transverse arch hypoplasia, even if the coarctation shelf itself is removed.

The incision should be planned according to:

1. Degree of proximal transverse arch hypoplasia
2. Distal arch and isthmus caliber
3. Location of the left carotid and left subclavian arteries
4. Size mismatch between the arch and descending aorta
5. Need for patch augmentation
6. Anticipated final curvature of the reconstructed arch

The aortotomy should create a broad pathway, not a narrow slit. The reconstructed arch should have a smooth transition from ascending aorta to transverse arch, distal arch, and descending aorta.

9. Posterior Wall Anastomosis

The posterior wall is the foundation of the repair. This deep portion of the anastomosis determines the effective diameter, alignment, and geometry of the reconstructed arch.

Technical priorities include:

1. Use full-thickness, evenly spaced bites.
2. Avoid purse-string narrowing.
3. Prevent posterior wall twisting.
4. Ensure that the descending aorta is not under tension.
5. Avoid leaving ductal tissue at the anastomotic margin.
6. Maintain a broad connection between arch and descending aorta.

A narrow posterior wall cannot be compensated for by a generous anterior wall. If the posterior suture line is small, the repair will remain functionally narrow.

10. Anterior Wall Completion

After the posterior wall is completed, the anterior wall is reconstructed. This completes the final arch geometry.

The surgeon should assess:

1. Anastomotic diameter
2. Arch curvature
3. Relationship to the arch branch vessels
4. Descending aortic alignment
5. Presence of kinking or narrowing
6. Bleeding from the posterior suture line
7. Tension on the reconstruction
8. Completeness of ductal tissue excision

The final repair should appear smooth and generous. A gothic, kinked, or acutely angulated arch may predispose to abnormal flow patterns, residual gradients, and late hypertension, even if the immediate anastomosis appears patent.

11. Weaning from Cardiopulmonary Bypass

After arch reconstruction, systemic perfusion is restored and the patient is rewarmed. If intracardiac repair is required, it is completed according to the operative plan. The patient is then separated from bypass after confirming adequate systemic perfusion and hemodynamic stability.

Before weaning from bypass, the team should evaluate:

1. Upper and lower body arterial pressures
2. Arch gradient
3. Femoral pulse quality
4. Ventricular function
5. Pulmonary blood flow
6. Lactate and acid-base status
7. Cerebral and somatic oxygenation
8. Bleeding from the arch reconstruction
9. Ventilation and lung recruitment

The innominate artery graft is divided or oversewn according to institutional practice. Hemostasis is secured, mediastinal drainage is placed, and the sternum is closed if physiology and bleeding are acceptable.

12. Outcomes and Evidence

Modern series suggest that median sternotomy arch repair can be performed with very low early mortality and acceptable morbidity in appropriately selected neonates and infants [1,3–5]. In a 15-year institutional analysis of 132 neonates and infants, the operative approach was selected according to anatomy, reflecting the principle that sternotomy and thoracotomy should not be viewed as interchangeable exposures but as anatomy-driven strategies [1].

In the series by Gray and colleagues, 62 neonates and infants underwent arch augmentation through median sternotomy, most commonly with homograft patch aortoplasty; there was no mortality, morbidity was low, and reintervention-free survival at 1, 3, and 5 years was reported as 87% [3]. Ashry and colleagues reported 76 neonates and infants undergoing homograft patch repair with no 30-day mortality, low neurologic adverse events, 5-year survival of 93.42%, and a 9.21% arch reintervention rate [4]. Costopoulos and colleagues described institutional adoption of a median sternotomy approach for coarctation with arch hypoplasia and concluded that sternotomy was safe, with low morbidity and mortality [5].

The importance of operative access is highlighted by Tulzer and colleagues, who reported that the lateral thoracotomy approach was a risk factor for recurrent obstruction in infants with coarctation and hypoplastic arch [2]. This does not mean that thoracotomy is inappropriate for all coarctation repairs. Rather, it emphasizes that thoracotomy may be inadequate when the disease extends into the transverse arch and requires proximal arch reconstruction.

13. Technical Pitfalls

13.1 Treating Coarctation as a Focal Lesion

A common conceptual error is to treat neonatal arch obstruction as a discrete narrowing. In many neonates, the disease involves the transverse arch, isthmus, ductal insertion, and proximal descending aorta. Failure to treat the full region risks residual obstruction.

13.2 Incomplete Ductal Tissue Excision

Residual ductal tissue may constrict postoperatively and contribute to recurrent narrowing. The anastomosis should be constructed from healthy aortic tissue whenever possible.

13.3 Insufficient Descending Aortic Mobilization

If the descending aorta is not adequately mobilized, the anastomosis may be placed under tension. This can narrow the repair, distort the arch, and increase bleeding risk.

13.4 Limited Arch Aortotomy

A short aortotomy may fail to address proximal transverse arch hypoplasia. The incision must be long enough to reconstruct the true extent of obstruction.

13.5 Narrow Posterior Wall

The posterior wall determines the functional caliber of the repair. A narrow posterior suture line is one of the most important technical causes of residual obstruction.

13.6 Branch Vessel Distortion

The reconstructed arch must preserve unobstructed flow to the innominate, left carotid, and left subclavian arteries. Branch vessel distortion can occur if the arch is reconstructed with excessive tension or poor geometry.

14. Postoperative Assessment

Postoperative evaluation focuses on whether the repair has restored unobstructed systemic blood flow.

Important findings include:

1. Upper and lower extremity blood pressure comparison
2. Femoral pulse quality
3. Urine output
4. Lactate clearance
5. Renal and hepatic perfusion
6. Left ventricular function
7. Residual arch gradient by echocardiography
8. Descending aortic Doppler pattern
9. Evidence of diastolic runoff
10. Vocal cord function if recurrent laryngeal nerve injury is suspected
11. Chylothorax surveillance when extensive mediastinal or descending aortic mobilization was required

A good repair should show minimal arm-leg gradient, strong distal pulses, preserved ventricular function, and a widely patent arch without significant Doppler obstruction.

15. Educational Summary

Aortic arch repair via median sternotomy is an anatomy-driven operation for neonates and infants in whom coarctation is associated with transverse arch hypoplasia, long-segment arch narrowing, or associated intracardiac disease. The operation combines controlled exposure, cardiopulmonary bypass, ductal division, coarctectomy, descending aortic mobilization, cerebral protection, and precise arch reconstruction.

The essential principles are:

1. Exposure: mobilize the arch, ductus, and descending aorta sufficiently.
2. Excision: remove coarctation and ductal tissue completely.
3. Perfusion: protect the brain and systemic organs during reconstruction.
4. Geometry: create a smooth, wide, tension-free arch.
5. Durability: avoid residual transverse arch hypoplasia and recurrent obstruction.

Median sternotomy is not simply a larger incision than thoracotomy. It is a different operative strategy that allows complete treatment of the proximal and distal arch, controlled cerebral perfusion, and concomitant intracardiac repair when needed. When the anatomy demands full arch reconstruction, median sternotomy provides a reliable platform for durable relief of neonatal arch obstruction.

References

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[2] Tulzer A, Mair R, Kreuzer M, Tulzer G. Outcome of aortic arch reconstruction in infants with coarctation: importance of operative approach. J Thorac Cardiovasc Surg. 2016;152(6):1506-1513.e1.

[3] Gray WH, Wells WJ, Starnes VA, Kumar SR. Arch augmentation via median sternotomy for coarctation of aorta with proximal arch hypoplasia. Ann Thorac Surg. 2018;106(4):1214-1219.

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[5] Costopoulos K, Philip J, Lopez-Colon D, Kaliki G, Chandran A, Bleiweis M. A single centre experience with an evolving approach for the repair of coarctation of the aorta. Cardiol Young. 2019;29(7):885-887.

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[8] Hornik CP. Commentary: Perfusion strategies for neonatal aortic arch repair, future strategies, and research opportunities. Semin Thorac Cardiovasc Surg. 2020;32(4):874-875.

[9] Lacour-Gayet F, Bruniaux J, Serraf A, Chambran P, Blaysat G, Losay J, Petit J, Kachaner J, Planché C. Hypoplastic transverse arch and coarctation in neonates: surgical reconstruction of the aortic arch. A study of sixty-six patients. J Thorac Cardiovasc Surg. 1990;100(6):808-816.

[10] Wright GE, Nowak CA, Goldberg CS, Ohye RG, Bove EL, Rocchini AP. Extended resection and end-to-end anastomosis for aortic coarctation in infants: results of a tailored surgical approach. Ann Thorac Surg. 2005;80(4):1453-1459.