Extended End-to-End Anastomosis via Left Thoracotomy #1: Left Thoracotomy, Dissection, and Exposure

1. Surgical Objective

Extended end-to-end anastomosis is a standard reconstructive strategy for native coarctation of the aorta in neonates and infants, particularly when focal coarctation is accompanied by hypoplasia of the isthmus or distal transverse arch. The objective is not simply to excise the visually narrowed segment. Successful repair requires removal or bypass of abnormal tissue, adequate enlargement of the hypoplastic arch segment, and creation of a broad anastomosis without excessive tension.

These principles are directly related to the risk of recurrent obstruction. Inadequate removal of ductal tissue, failure to address associated arch hypoplasia, and excessive suture-line tension have all been identified as mechanisms contributing to early recurrent coarctation [1]. Consequently, the quality of the reconstruction is determined partly before the aorta is clamped: exposure and mobilization establish whether a sufficiently extensive, tension-free reconstruction can be achieved.

The initial phase of the operation therefore has three major objectives:

1. Establish appropriate exposure through a left posterolateral thoracotomy.
2. Define and mobilize the distal arch, branch vessels, ductal region, and descending aorta.
3. Identify and preserve the neural, lymphatic, venous, and collateral structures surrounding the aortic arch.

2. Left Posterolateral Thoracotomy

A left posterolateral thoracotomy through the third intercostal space provides direct access to the distal transverse arch, isthmus, ductus arteriosus, and proximal descending thoracic aorta.

The relatively high intercostal entry is important because extended repair requires proximal exposure well beyond the discrete coarctation. The operative field must permit visualization and mobilization of:

• Distal transverse aortic arch
• Left carotid artery
• Left subclavian artery
• Aortic isthmus
• Ductus arteriosus or ligamentum arteriosum
• Coarctation segment
• Proximal descending thoracic aorta

The choice between thoracotomy and a sternotomy-based arch reconstruction should not be determined solely by the presence of coarctation. The extent and location of arch hypoplasia are fundamental to operative planning. Histologic and clinical studies support repair through left thoracotomy when the proximal arch is sufficiently developed, whereas marked proximal transverse arch hypoplasia or associated intracardiac lesions requiring repair may favor reconstruction through median sternotomy [2].

Thus, preoperative echocardiographic and cross-sectional assessment of the entire arch—not merely the narrowest coarctation diameter—is essential.

3. Defining the Aortic Anatomy Before Dissection

The visible coarctation shelf represents only one component of the obstructive anatomy. Before proceeding with extensive mobilization, the surgeon should define the complete relationship among:

• Ascending and transverse aortic arch
• Brachiocephalic artery
• Left carotid artery
• Left subclavian artery
• Distal transverse arch
• Isthmus
• Ductal insertion
• Descending thoracic aorta
• Intercostal arteries

Particular attention should be directed toward the dimensions of the distal transverse arch and isthmus. Preoperative arch dimensions influence operative strategy, and smaller isthmic dimensions have been associated with subsequent reintervention after repair through lateral thoracotomy [3].

In neonates, the ductus may remain large and patent, and systemic perfusion can remain partially ductal dependent. In older infants, the ductus may have involuted into the ligamentum arteriosum. In either situation, the ductal insertion serves as a critical anatomical landmark because ductal tissue can extend into the adjacent aortic wall.

4. Initial Exposure and Mobilization

After entering the chest, the mediastinal pleura is opened to expose the descending thoracic aorta and distal arch. Dissection should proceed within recognizable tissue planes and under direct visualization.

The goal is not simply to expose the stenotic segment. Sufficient normal aorta must be identified both proximal and distal to the coarctation to permit safe clamp placement, complete treatment of abnormal tissue, and creation of an appropriately extended anastomosis.

Mobilization should be systematic. The distal arch, left carotid artery, left subclavian artery, ductal region, and descending aorta are progressively released from surrounding tissues. This transforms a relatively fixed arch-descending aortic junction into mobile vascular segments that can be approximated without distortion.

This concept is particularly important when arch hypoplasia extends proximal to the isthmus. In such patients, simply resecting the discrete narrowing and performing a conventional end-to-end anastomosis may leave residual proximal obstruction. Tailored enlargement of the distal arch, including combinations of extended end-to-end reconstruction with additional arch augmentation techniques, has been used successfully in neonates with substantial distal arch hypoplasia [4].

5. Mobilization of the Distal Aortic Arch

Adequate proximal mobilization is a defining feature of extended reconstruction.

The distal transverse arch is dissected sufficiently to identify the origins of the left carotid and left subclavian arteries. Mobilization around these vessels provides several advantages:

• Defines the true proximal extent of arch hypoplasia
• Facilitates safe vascular clamp placement
• Increases mobility of the distal arch
• Permits extension of the proximal incision into healthier tissue
• Reduces tension during approximation to the descending aorta

The left subclavian artery is especially important because its origin lies immediately adjacent to the isthmus and ductal region. The transition from distal arch to isthmus should therefore be clearly visualized.

More extensive proximal arch hypoplasia may exceed what can be adequately addressed by a conventional extended end-to-end repair through thoracotomy. In one comparative experience, patients with significant proximal arch hypoplasia treated with a modified end-to-side reconstruction had no residual gradient during follow-up, whereas early proximal arch restenosis occurred in patients treated with extended end-to-end repair [5]. This emphasizes that the operative technique must be matched to the distribution of arch hypoplasia rather than applied uniformly to all coarctation anatomy.

6. Mobilization of the Descending Aorta

Distal mobilization is equally important.

The descending thoracic aorta should be freed sufficiently to allow it to move cephalad toward the distal arch without excessive longitudinal tension. If the two vascular segments meet only after substantial traction is applied, further mobilization should be considered before accepting the reconstructive geometry.

Several intercostal arteries originate from the posterior descending aorta. These branches must be recognized during circumferential dissection. Blind passage of instruments behind the aorta should be avoided whenever possible.

In older infants or children with longstanding obstruction, collateral vessels may be considerably larger than in neonates. Their injury can produce significant bleeding and compromise visualization. Meticulous dissection and hemostasis are therefore particularly important before aortic clamping.

The operative endpoint is not maximum mobilization for its own sake, but sufficient mobility to create a broad anastomosis without tension, torsion, or distortion of the reconstructed arch.

7. Ductus Arteriosus and Ductal Tissue

The relationship between coarctation and the ductal insertion has important surgical implications.

Histologic examination of resected specimens has demonstrated that ductal tissue may extend beyond the obvious ductal junction into the adjacent aortic wall. In a series of neonates and young infants, ductal tissue extended into the lateral aortic wall, supporting the concept that incomplete treatment of this region may permit later constriction as ductal tissue involutes [2].

Accordingly, successful reconstruction should avoid leaving a substantial circumferential component of abnormal ductal tissue within the reconstructed lumen.

Rajasinghe and colleagues specifically identified inadequate removal of ductal tissue, failure to address arch hypoplasia, and suture-line tension as important causes of recurrent obstruction. Their technique emphasized extensive mobilization, removal of potentially abnormal tissue, and extended anastomosis of the descending aorta to the undersurface of the arch; 21 of 22 late survivors remained free of recurrent coarctation [1].

This provides an important conceptual distinction: coarctation repair is not simply division and reconnection at the narrowest point but reconstruction of the entire abnormal ductal–isthmic–arch region.

8. Left Vagus and Recurrent Laryngeal Nerves

The left vagus nerve and left recurrent laryngeal nerve are among the most important nonvascular structures encountered during the exposure.

The left vagus descends adjacent to the aortic arch. The recurrent laryngeal nerve branches from the vagus and loops around the undersurface of the arch in close relationship to the ductus or ligamentum arteriosum before ascending toward the larynx.

This course places the recurrent nerve directly within the area required for ductal and distal arch mobilization.

Particular caution is required during:

• Circumferential dissection of the ductus or ligamentum
• Division of ductal tissue
• Mobilization of the undersurface of the distal arch
• Placement of vascular loops or clamps
• Retraction of the arch and surrounding tissues

Direct transection is not required to produce dysfunction. Traction, thermal injury, compression, or entrapment in a ligature may also damage the nerve.

The early series reported by Rajasinghe and colleagues included one recurrent laryngeal nerve injury among 23 neonates and infants [1]. Although this does not establish a contemporary incidence, it illustrates the anatomical vulnerability of the nerve during extensive arch reconstruction.

Postoperative recurrent laryngeal nerve dysfunction may present with a weak or hoarse cry, stridor, impaired swallowing, aspiration, or feeding difficulty and should be considered when these findings occur after repair.

9. Thoracic Duct and Lymphatic Structures

The thoracic duct lies posteriorly within the mediastinum and is potentially vulnerable during deep dissection around the descending aorta and distal arch.

Its anatomy is variable, and it may not be directly visualized during routine exposure. Nevertheless, unnecessary posterior dissection should be minimized because lymphatic disruption can result in postoperative chylous drainage.

The available outcome series used for this review do not provide sufficiently detailed data to quantify the incidence of chylothorax specifically after extended end-to-end repair. Therefore, thoracic duct injury should be regarded primarily as an anatomically plausible and clinically important complication rather than one whose frequency can be defined from the current evidence set.

10. Superior Intercostal Vein, Intercostal Arteries, and Collateral Vessels

The left superior intercostal vein may cross the operative field near the distal arch and should be identified during proximal exposure.

Intercostal arteries arising from the descending aorta require similar attention during distal mobilization. In patients with more severe or longstanding obstruction, collateral arterial pathways may be prominent and can complicate dissection.

These vessels should be managed under direct visualization. Even relatively small collateral branches may cause troublesome bleeding within the confined thoracotomy field and impair identification of the recurrent nerve, ductal region, or posterior aortic wall.

As with chylothorax, the available clinical series do not provide sufficiently specific data to define the incidence of collateral-vessel complications. Their importance in this phase of the operation is therefore primarily technical: careful identification and hemostasis preserve a clean operative field and facilitate subsequent vascular control.

11. The Principle of a Tension-Free Reconstruction

One of the most important objectives of exposure is to ensure that the eventual anastomosis is not created under excessive tension.

The following structures may require mobilization:

• Distal transverse arch
• Left carotid artery
• Left subclavian artery
• Ductus or ligamentum
• Proximal descending thoracic aorta

Suture-line tension was specifically recognized as a potential mechanism of recurrence in early extended reconstruction experience [1]. Rather than using sutures to forcibly approximate relatively fixed segments, the surgeon should create mobility before clamping.

This principle also explains why the distribution of arch hypoplasia affects technique selection. When adequate mobility and a broad reconstruction can be achieved through thoracotomy, excellent results are possible. Conversely, more extensive proximal arch disease may require an end-to-side reconstruction or sternotomy-based approach to avoid leaving residual obstruction.

12. Preparing for Vascular Control

Before aortic clamping, the surgeon should confirm:

• Adequate proximal and distal aortic exposure
• Clear identification of the left carotid and left subclavian arteries
• Definition of the extent of distal arch and isthmic hypoplasia
• Complete understanding of ductal anatomy
• A safe proximal clamp position
• A safe distal clamp position
• Adequate mobility of the descending aorta
• Protection of the vagus and recurrent laryngeal nerves
• Identification or avoidance of significant intercostal and collateral vessels

The operative field should permit placement of clamps without trapping surrounding neural or vascular structures.

This assessment is particularly important in neonates with small transverse arches. The final decision regarding the extent of reconstruction should be made before ischemic time begins whenever possible.

13. Recurrent Obstruction and the Importance of Surgical Strategy

Contemporary series confirm that recurrent arch obstruction remains clinically relevant despite generally excellent survival.

In a retrospective series of 183 infants undergoing aortic arch reconstruction, lateral thoracotomy was identified as a risk factor for recurrent obstruction, although 10-year freedom from reintervention remained 90.1% [6]. This observation should not be interpreted as evidence that thoracotomy itself is inherently inadequate; rather, it emphasizes the importance of patient selection and the relationship between operative access and the extent of arch pathology.

A larger series of 340 neonates with coarctation, many with associated distal arch hypoplasia, demonstrated hospital mortality of only 0.6%. Recurrent arch obstruction requiring intervention occurred in 33 patients, approximately 9.7% of the cohort. The authors emphasized a tailored surgical strategy according to arch anatomy [7].

Similarly, long-term follow-up after extended end-to-end repair through left thoracotomy has demonstrated recurrent arch obstruction in approximately 8% of patients, while also documenting significant subsequent growth of initially hypoplastic transverse arches [8].

More recent experience reinforces the same principle. In a 15-year series of 132 neonates and infants, selecting the operative approach according to individual arch anatomy was associated with operative mortality below 1%, transcatheter intervention for recurrent coarctation in 5.3%, and surgical reintervention in 2.3% [9].

Taken together, these studies support an anatomy-driven strategy rather than a single universal reconstruction for all forms of neonatal coarctation.

14. Common Technical Pitfalls

Inadequate proximal mobilization

Failure to mobilize the distal arch and branch vessels may restrict the extent of reconstruction and increase anastomotic tension.

Inadequate distal mobilization

Insufficient release of the descending aorta prevents cephalad displacement and may distort the anastomosis.

Incomplete treatment of ductal tissue

Residual ductal tissue within the reconstructed region may contribute to secondary narrowing as the tissue involutes [1,2].

Failure to address arch hypoplasia

A technically satisfactory anastomosis at the coarctation site may still leave clinically important proximal arch obstruction [4,5].

Recurrent laryngeal nerve injury

The nerve is particularly vulnerable during ductal dissection and mobilization of the undersurface of the arch.

Injury to intercostal or collateral vessels

Bleeding can obscure the field and complicate subsequent clamp placement.

These pitfalls reinforce that the dissection phase is an integral component of the reconstruction rather than merely preparation for the anastomosis.

15. Surgical Endpoint of the Exposure Phase

Before proceeding to clamping and reconstruction, the entire coarctation complex should be clearly defined.

The distal arch, left carotid artery, left subclavian artery, isthmus, ductal region, and descending aorta should be adequately visualized and mobilized. The descending aorta should reach the distal arch without excessive traction, and the surgeon should understand how far proximally the reconstruction must extend to bypass or enlarge hypoplastic tissue.

At the same time, the vagus and recurrent laryngeal nerves, thoracic duct region, superior intercostal vein, intercostal arteries, and collateral vessels should remain protected.

The fundamental surgical principle is therefore straightforward: a durable extended end-to-end repair begins with complete anatomical understanding, adequate mobilization, appropriate treatment of ductal and hypoplastic tissue, and preparation for a broad, tension-free reconstruction.

References

[1] Rajasinghe H, Reddy VM, van Son JA, Black MD, McElhinney DB, Brook MM, Hanley FL. Coarctation repair using end-to-side anastomosis of descending aorta to proximal aortic arch. Ann Thorac Surg. 1996. doi:10.1016/0003-4975(95)01153-6.

[2] van Son JA, Falk V, Schneider P, Smedts F, Mohr F. Repair of coarctation of the aorta in neonates and young infants. J Card Surg. 1997. doi:10.1111/j.1540-8191.1997.tb00114.x.

[3] Ramachandran P, Khoury P, Beekman R, Michelfelder E, Manning P, Tweddell J, Cnota J. Preoperative aortic arch size and late outcome after coarctation repair by lateral thoracotomy. Ann Thorac Surg. 2018. doi:10.1016/j.athoracsur.2018.03.084.

[4] Poncelet A, Henkens A, Sluysmans T, Moniotte S, de Beco G, Momeni M, Detaille T, Rubay J. Distal aortic arch hypoplasia and coarctation repair: a tailored enlargement technique. World J Pediatr Congenit Heart Surg. 2018. doi:10.1177/2150135118780611.

[5] Dharmapuram A, Ramadoss N, Verma S, Vejendla G, Ivatury R. Early outcomes of modification of end to side repair of coarctation of aorta with arch hypoplasia in neonates and infants. Ann Pediatr Cardiol. 2018. doi:10.4103/apc.APC_5_18.

[6] 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. doi:10.1016/j.jtcvs.2016.08.029.

[7] Provost B, Fournier E, Hascoët S, Le Bret E, Roussin R, Zoghbi J, Belli E. Aortic coarctation associated with distal aortic arch hypoplasia in neonates can be effectively repaired through left thoracotomy. J Card Surg. 2023. doi:10.1155/2023/5599161.

[8] Belyaeva MM, Ilyin V, Kornouhov OY, Kornouhov YY, Kalinina O. Coarctation repair through left thoracotomy in neonates and infants. Patologiya krovoobrashcheniya i kardiokhirurgiya. 2018. doi:10.21688/1681-3472-2018-4-12-20.

[9] Stukov Y, Jacobs J, Sharaf OM, Peek GJ, Pitkin A, Cruz Beltrán SC, Lopez-Colon D, Nixon CS, Bleiweis M. 15-year analysis of surgical approaches and outcomes for coarctation in 132 neonates and infants. Pediatr Cardiol. 2024. doi:10.1007/s00246-023-03360-1.