Anomalous Aortic Origin of a Coronary Artery #3: Surgical Procedure of Unroofing

Surgical Procedure: Unroofing for AAOCA

Unroofing is one of the principal surgical strategies for anomalous aortic origin of a coronary artery (AAOCA) when the anomalous coronary artery has a significant intramural segment. In this anatomy, the proximal coronary artery does not immediately enter the epicardial surface after arising from the opposite sinus. Instead, it travels within the aortic wall, sharing a common wall with the aortic lumen before exiting toward its normal epicardial course.

The objective of unroofing is to eliminate this intramural tunnel and create a wide, unobstructed neo-ostium in the appropriate sinus. Although the concept is straightforward, the procedure requires precise understanding of the intramural course, its relationship to the aortic valve commissures, and the distal exit point of the coronary artery. The operation should therefore be viewed not simply as “opening the coronary,” but as a controlled reconstruction of the proximal coronary entrance.

Contemporary surgical decision-making has also become more anatomy-specific. Unroofing is particularly suitable for a long intramural segment that courses above the aortic valve, whereas neo-ostium creation or coronary reimplantation may be preferred in selected anatomies, especially when the intramural segment is short, low, or absent [1].

1. Anatomical Rationale

In AAOCA with an intramural course, several anatomical features may contribute to myocardial ischemia:

1. Slit-like coronary ostium

The anomalous ostium may be narrow, elongated, or tangentially oriented, limiting coronary inflow.

2. Acute takeoff angle

The coronary artery may arise at an unfavorable angle from the aorta, producing a sharp bend at the proximal segment.

3. Intramural lateral compression

The coronary lumen may be compressed within the aortic wall, particularly during high-pressure or high-flow states.

4. Dynamic obstruction during exertion

The intramural segment may become more compromised during exercise, tachycardia, or increased aortic root expansion.

Unroofing addresses these mechanisms by opening the shared wall between the aortic lumen and the intramural coronary lumen. This converts the tunneled segment into a broad communication with the aortic sinus, thereby creating a more physiologic coronary inflow pathway.

Early and intermediate clinical series have shown that surgical correction can be performed with low operative mortality and good symptom relief when patients are appropriately selected [2–6].

2. Operative Exposure and Initial Assessment

The operation is generally performed with cardiopulmonary bypass and cardioplegic arrest. After aortotomy, the aortic root is inspected from within. The surgeon must identify the anomalous coronary ostium and define the direction of the intramural segment.

The key landmarks are:

• Anomalous coronary ostium
• Intramural coronary segment
• Distal exit point of the coronary artery
• Aortic valve leaflets
• Intercoronary commissure
• Relationship between the intramural segment and the commissure

This assessment determines whether simple unroofing is sufficient or whether commissural takedown, commissural resuspension, neo-ostium creation, or coronary reimplantation should be considered.

A critical principle is that the surgeon must distinguish the true coronary lumen from the adjacent aortic wall. The incision should remain within the common wall between the aorta and coronary artery. Deviation outside this plane can result in a false passage, aortic wall injury, or coronary injury.

3. Traction Stay Sutures

After the intramural course is identified, traction stay sutures may be placed along the common wall. These sutures are not merely for exposure; they help define the geometry of the operation.

They serve four practical purposes:

1. Expose the intramural tunnel

Gentle traction opens the operative field and improves visualization.

2. Clarify the direction of the coronary course

The surgeon can follow the natural path of the intramural segment rather than incising blindly.

3. Maintain control during stepwise unroofing

The common wall can be opened progressively, reducing the risk of uncontrolled extension.

4. Prevent disorientation between the aortic and coronary lumens

This is especially important when the intramural course is curved, long, or closely related to the aortic valve commissure.

The use of traction is particularly helpful in pediatric patients, in whom the operative field is small and the intramural coronary segment may be delicate.

4. Stepwise Unroofing of the Common Wall

The common wall is incised longitudinally, starting from the anomalous ostium and extending along the intramural course. The incision is advanced gradually toward the distal exit point of the coronary artery.

The essential technical principle is:

Open the shared wall between the aorta and coronary artery; do not enter the external aortic wall.

A controlled sequence is useful:

1. Identify the anomalous ostium.
2. Confirm the direction of the intramural course.
3. Place traction stay sutures as needed.
4. Incise the common wall longitudinally.
5. Extend the unroofing stepwise along the intramural segment.
6. Stop at the distal end of the intramural course.
7. Confirm a wide, smooth neo-ostium.

The final opening should be generous and nonrestrictive. A small, irregular, or eccentric neo-ostium may leave residual obstruction despite technically “opening” the intramural segment.

Several series have shown that unroofing provides excellent early outcomes and symptomatic improvement, but the quality of the repair depends heavily on complete relief of the intramural obstruction and avoidance of aortic valve distortion [3–6].

5. Determining Where to Stop

One of the most important decisions during unroofing is determining the distal endpoint of the incision.

The incision should stop where the coronary artery exits the aortic wall and becomes a normal extramural coronary artery. Extending beyond this point is dangerous because the surgeon may leave the coronary lumen and enter the aortic wall or surrounding tissue.

Warning signs that the incision is approaching an unsafe plane include:

• Loss of a clearly identifiable coronary lumen
• Thinning of the tissue plane
• Deviation away from the expected coronary course
• Excessive resistance to incision
• Proximity to leaflet attachment or commissural tissue
• Distortion of the aortic sinus or valve commissure

The goal is not to make the longest possible incision. The goal is to open the entire intramural segment while preserving the distal coronary artery, the aortic wall, and the aortic valve.

6. Commissural Involvement and Resuspension

In some patients, the intramural coronary segment passes close to or beneath an aortic valve commissure. In this setting, complete unroofing may require temporary takedown of the commissure. After the intramural segment is opened, the commissure must be resuspended carefully to preserve aortic valve competence.

This step is important because commissural involvement creates a balance between two competing risks:

1. Incomplete unroofing

Avoiding the commissure may leave part of the intramural segment untreated, resulting in residual coronary narrowing.

2. Aortic valve insufficiency

Aggressive unroofing without appropriate commissural reconstruction may destabilize the commissure and produce postoperative aortic regurgitation.

Clinical data support the importance of commissural resuspension when complete unroofing involves commissural manipulation. In a mid-term outcomes study, routine commissural resuspension was associated with a lower rate of postoperative aortic regurgitation without compromising relief of ischemia [8].

Therefore, commissural involvement should not be viewed as a reason to perform an incomplete operation. Rather, it should prompt a deliberate plan for commissural takedown and precise resuspension when anatomically required.

7. Technical Variations

Although classic unroofing involves sharp incision or excision of the shared wall, several technical variations have been described. In adult patients, a technique using electrical fulguration to remove the shared intramural wall has been reported as a feasible alternative to traditional sharp excision, with the proposed advantage of technical efficiency and controlled removal of the common wall [7].

Other surgical strategies may be more appropriate depending on anatomy:

• Neo-ostium creation may be considered when the intramural segment is long but courses below the level of the aortic valve.
• Coronary reimplantation may be preferable when the intramural segment is short, absent, or not favorably positioned for complete unroofing.
• Anatomical repair or coronary translocation has been proposed as an alternative to unroofing in selected cases, particularly when the anatomy is not ideal for safe and durable unroofing [9].

Thus, unroofing should not be applied reflexively to all AAOCA patients. The operative strategy should be selected according to the length, height, and orientation of the intramural course, as well as its relationship to the commissure and aortic valve.

8. Expected Outcomes

Published surgical series generally demonstrate that repair of AAOCA can be performed with very low early mortality and good symptomatic improvement [2–6]. In many patients, symptoms such as chest pain, syncope, or exertional limitation improve after correction of the intramural obstruction.

However, the absence of early mortality does not mean that all repairs are equivalent. Important postoperative endpoints include:

• Resolution of ischemic symptoms
• Absence of residual coronary obstruction
• Freedom from sudden cardiac events
• Preservation of aortic valve competence
• Freedom from reoperation
• Return to activity after appropriate evaluation
• Long-term surveillance of the reconstructed coronary origin

A large contemporary series of 230 patients reported low mortality and low overall reoperation rates, but also suggested that the durability of repair may differ by technique, with reoperation occurring in the unroofing cohort but not in the reimplantation cohort in that series [10]. This finding supports the current trend toward more anatomy-specific surgical planning rather than a single-technique approach for all AAOCA variants.

9. Technical Pitfalls

Several pitfalls should be actively avoided.

1. Incomplete unroofing

If the incision does not reach the true distal end of the intramural segment, a residual narrowed segment may remain. This may limit the effectiveness of the operation.

2. Overextension beyond the coronary lumen

Extending the incision beyond the intramural segment may create a false passage or injure the aortic wall or coronary artery. The surgeon should stop once the coronary exits the aortic wall.

3. Commissural distortion

If the intramural segment involves the commissure, unroofing without appropriate commissural resuspension may cause aortic regurgitation.

4. Small or irregular neo-ostium

The reconstructed ostium must be wide, smooth, and nonrestrictive. A narrow or jagged neo-ostium may remain functionally obstructive.

5. Wrong procedure for the anatomy

Unroofing may not be ideal for short intramural segments, low intramural courses, or anatomies in which the coronary does not have a meaningful intramural component. In such cases, reimplantation or neo-ostium creation may provide a more durable anatomical correction [1, 9, 10].

10. Practical Surgical Summary

Unroofing for AAOCA can be summarized as a sequence of anatomical decisions:

1. Open the aorta and identify the anomalous ostium.
2. Define the length and direction of the intramural coronary segment.
3. Assess the relationship to the aortic valve commissure.
4. Place traction stay sutures to expose and orient the common wall.
5. Incise the common wall longitudinally from the ostium.
6. Extend the incision stepwise along the intramural course.
7. Stop at the distal end of the intramural segment.
8. Take down and resuspend the commissure if required.
9. Confirm a wide neo-ostium and preserved aortic valve competence.
10. Consider alternative repair strategies if anatomy is unfavorable for complete unroofing.

11. Key Message

Unroofing for AAOCA is an anatomical operation designed to eliminate the intramural coronary tunnel and create a wide, physiologic neo-ostium. The surgeon must identify the true intramural course, open the shared wall completely, and stop before the incision leaves the coronary lumen.

When the intramural segment involves an aortic valve commissure, complete unroofing may require commissural takedown and resuspension to avoid residual obstruction while preserving valve competence. Current evidence supports the safety and effectiveness of unroofing in appropriately selected patients, but modern surgical planning should remain anatomy-specific. In selected cases, neo-ostium creation or coronary reimplantation may offer a better anatomical solution than unroofing alone.

The technical endpoint is a wide, smooth, non-compressed coronary entrance that restores physiologic coronary inflow without creating aortic valve dysfunction.

References

[1] Mery CM, Beckerman Z. What is the Optimal Surgical Technique for Anomalous Aortic Origin of a Coronary Artery? Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2025;28:94-100.

[2] Romp RL, Herlong JR, Landolfo CK, Sanders SP, Miller CE, Ungerleider RM, Jaggers J. Outcome of unroofing procedure for repair of anomalous aortic origin of left or right coronary artery. Ann Thorac Surg. 2003;76(2):589-596.

[3] Davies JE, Burkhart HM, Dearani JA, Suri RM, Phillips SD, Warnes CA, Sundt TM 3rd, Schaff HV. Surgical management of anomalous aortic origin of a coronary artery. Ann Thorac Surg. 2009;88(3):844-847.

[4] Mumtaz MA, Lorber RE, Arruda J, Pettersson GB, Mavroudis C. Surgery for anomalous aortic origin of the coronary artery. Ann Thorac Surg. 2011;91(3):811-815.

[5] Mainwaring RD, Reddy VM, Reinhartz O, Petrossian E, Punn R, Hanley FL. Surgical repair of anomalous aortic origin of a coronary artery. Eur J Cardiothorac Surg. 2014;46(1):20-26.

[6] Sharma V, Burkhart HM, Dearani JA, Suri RM, Daly RC, Park SJ, Horner JM, Phillips SD, Schaff HV. Surgical unroofing of anomalous aortic origin of a coronary artery: a single-center experience. Ann Thorac Surg. 2014;98(3):941-945.

[7] Vinnakota A, Stewart RD, Najm HK, Blackstone EH, Ghobrial J, Pettersson GB. Anomalous Aortic Origin of the Coronary Arteries: A Novel Unroofing Technique in an Adult Cohort. Ann Thorac Surg. 2019;107(3):823-828.

[8] Yerebakan C, Ozturk M, Mota L, Sinha L, Gordish-Dressman H, Jonas RA, Sinha P. Complete unroofing of the intramural coronary artery for anomalous aortic origin of a coronary artery: the role of commissural resuspension? J Thorac Cardiovasc Surg. 2019;158(1):208-217.e2.

[9] Gaillard M, Pontailler M, Danial P, Moreau de Bellaing A, Gaudin R, du Puy-Montbrun L, Murtuza B, Haydar A, Malekzadeh-Milani S, Bonnet D, Vouhé P, Raisky O. Anomalous aortic origin of coronary arteries: an alternative to the unroofing strategy. Eur J Cardiothorac Surg. 2020;58(5):975-982.

[10] Mainwaring RD, Ma M, Maskatia S, Petrossian E, Reinhartz O, Lee JD, Hanley FL. Outcomes of 230 Patients Undergoing Surgical Repair of Anomalous Aortic Origin of a Coronary Artery. Ann Thorac Surg. 2025;119(6):1297-1305.