Intramural Coronary Artery Unroofing

Introduction

Intramural coronary arteries are a rare congenital coronary malformation that are infrequently seen in adult patients. This video shows the management of two intramural coronary arteries: one of the right coronary artery and one of the left.

Case 1 - Intramural Right Coronary Artery

The first case involves a 48-year-old woman who presented with episodes of angina and was admitted for an NSTEMI. The coronary computed tomography (CT) scan showed an anomalous right coronary artery, with the ostium originating adjacent to the left main ostium in the left sinus and coursing between the aorta and pulmonary artery (interarterial course). Given her symptoms, the patient was brought to the operating room for surgical repair.

Before initiating cardiopulmonary bypass, the pulmonary artery was dissected free from the aorta, starting with the right pulmonary artery and then advancing carefully down to the main pulmonary artery (MPA). The intramural right coronary artery (RCA) ostium was identified, and its intramural course could be seen within the aorta. Heparin was administered and cardiopulmonary bypass was initiated through aortic and right atrial cannulation. On an empty beating heart, the aortic root was further dissected out and the proximal RCA was freed.

The aorta was cross-clamped and the heart was arrested with cold blood cardioplegia. A transverse aortotomy was performed. A coronary probe was passed through the right ostium, with its course in the aortic root wall. The intramural portion was unroofed using a beaver-blade over the coronary probe. The intramural portion coursed behind the right-left commissure, which was marked with a stay suture. The unroofing continued behind the commissure all the way to the exit of the RCA from the right aortic sinus. The tissue covering the intramural course was resected with the beaver blade. The unroofing was then marsupialized, apposing the endothelium in the coronary artery to the aortic sinus endothelium, to avoid a potential plane for dissection or bleeding once the cross-clamp was removed. This was done using a 6-0 or 7-0 polypropylene suture. The right-left commissure, which was taken down during the unroofing, was reattached to the aortic wall. The aortic valve was inspected to ensure good function and coaptation.

Case 2 - Intramural Left Coronary Artery

The second case involves a 63-year-old woman who presented with severe and symptomatic aortic stenosis. The preoperative coronary CT showed a left main coronary coming from the anterior right sinus, adjacent to the RCA ostium, and coursing between the aorta and pulmonary artery.

The heart was accessed through a median sternotomy and cardiopulmonary bypass was initiated after aortic and right atrial cannulation. On an empty beating heart, the MPA was dissected free from the aorta. The intramural left main was identified and dissected free.  The aortic root was further dissected free towards the right, to identify the proximal right coronary artery. After cross-clamping the aorta and arresting the heart with cold blood cardioplegia, a transverse aortotomy was performed. The stenotic aortic valve was resected.

The intramural left coronary artery was unroofed, coursing behind the left-right commissure towards the left sinus. A probe was inserted in the intramural portion to help identify the exact course and avoid damaging the aortic wall. Extra tissue covering the intramural course was resected, and the unroofing was then marsupialized, apposing the endothelium in the coronary artery to the aortic sinus endothelium. The left main coronary artery was then probed to ensure it remained patent after repair. The aortic valve was then replaced using a bioprosthetic valve. The left main ostium was probed after valve insertion.

Comment

Both patients had an uneventful postoperative course and remain symptom free. Augmenting the neo-ostium with a saphenous vein patch has been proposed to avoid the risk of coronary occlusion, if the unroofing is too limited. The authors believe that this technique of unroofing is straightforward, and that marsupialization after unroofing is critical to avoid a plane for dissection or bleeding after releasing the aortic cross-clamp.