What is coronary unroofing?

Coronary Unroofing: Surgical Technique for Anomalous Coronary Arteries

Coronary unroofing is a surgical procedure that removes the shared intramural wall segment between an anomalous coronary artery and the aorta, creating a large neo-ostium in the appropriate sinus and eliminating the interarterial course without requiring coronary reimplantation. 1

Surgical Technique

The unroofing procedure involves specific technical steps:

• The intramural segment of the anomalous coronary artery is opened by transecting or excising the endothelial tissue flap that forms the shared wall between the coronary artery and the aortic lumen 2
• The procedure creates a neo-ostium perpendicular to the aortic root in the appropriate sinus of Valsalva, allowing unobstructed coronary egress 1
• Two technical approaches exist: traditional sharp excision of the shared wall or electrical fulguration (burning) of the intramural segment, with fulguration requiring shorter cardiopulmonary bypass times (39 vs 62 minutes, p=0.02) while maintaining equal safety and effectiveness 3
• The neo-ostium is marsupialized with interrupted sutures to reapproximate the endothelium and prevent aortic dissection 2
• Resection is limited to the intramural portion only to avoid extra-aortic incision 2

Anatomic Requirements and Limitations

Unroofing is only feasible when a distinct intramural segment exists that can be opened without compromising the coronary artery 4:

• The procedure requires that the anomalous coronary has a clearly defined intramural course within the aortic wall 4
• When no distinct intramural segment is present, alternative techniques must be used: coronary reimplantation (5% of cases), coronary artery bypass grafting (7%), or pulmonary artery translocation (8%) 4
• Unroofing may not be appropriate if the procedure would result in compression by the intercoronary pillar or fails to relocate the ostium to the appropriate sinus 5

Clinical Indications

The procedure is performed for anomalous aortic origin of coronary arteries (AAOCA) with specific high-risk features:

• Anomalous left coronary artery from the right sinus with interarterial course carries the highest risk and warrants surgical intervention in adults unless surgery poses prohibitive risk 1
• Symptomatic patients with documented ischemia or ventricular arrhythmias require surgical repair 1
• High-risk anatomic features include: slit-like or fish-mouth ostium, acute angle takeoff, intramural course, and interarterial course between the aorta and pulmonary artery 1, 6

Outcomes and Follow-up

Surgical unroofing demonstrates excellent short and intermediate-term results:

• No early deaths and 1% late death from noncardiac causes in a series of 75 patients 7
• Resolution of symptoms in 82% of patients (28 of 34) at average 5-year follow-up 3
• All patients remained free of cardiac symptoms at mean 18-month follow-up in one series 7
• 93-94% of patients are released to unrestricted exercise activities after recovery 5
• Postoperative imaging shows patent, non-restrictive coronary ostia in all cases with follow-up CT angiography 4

Common Pitfalls

The slit-like orifice is the major factor responsible for myocardial ischemia and is more commonly seen in anomalous right coronary artery arising from the left sinus 2. Failure to adequately address this during unroofing can lead to persistent symptoms.

Preoperative stress testing is unreliable: only 50% of symptomatic patients with AAOCA demonstrate abnormal stress test results 7, and patients with normal stress tests have still experienced sudden cardiac death 1. Therefore, anatomic features on CT angiography should guide surgical decision-making rather than stress test results alone.

Reintervention may be required in rare cases: one patient required subsequent transection and reimplantation after unroofing due to recurrent aborted sudden cardiac death 5, and two patients needed coronary artery bypass grafting due to flow acceleration at the ostium 7.