Deep Dive Into Aortic Surgery: Acute Type A Dissection—Its Last Line of Defense

An eighty-four-year-old woman presented with acute type A aortic dissection and blood in the pericardial sac. The dissection was contained by the visceral pericardial layer (i.e. the last line of defense). The patient underwent a successful emergency aortic repair at the Royal Prince Alfred Hospital, Sydney, Australia.

First, a midline incision was performed from the manubriosternal junction to the xiphoid. The incision was developed through the subcutaneous fat onto the body of the sternum using diathermy. Sternotomy was performed using an electrical saw. Hemostasis was performed, including application of small amount of bone wax to bone marrow. The thymic fat pad was completely resected, exposing the innominate vein superiorly and the great vessels superior-laterally. The pericardium was then opened longitudinally. The ascending aorta was aneurysmal and tense. The bloody pericardial effusion was drained, and the hemodynamic parameters improved.

Next, three pericardial traction sutures were placed on each side. The supra-aortic branches were dissected free as much as possible before going on the cardiopulmonary bypass (CPB). After systemic heparinization, the right axillary cannulation strategy was used. A multistage femoral venous cannula was inserted under transesophageal echo guidance. The CPB was established, and systemic cooling toward 25 degrees centigrade was initiated. A left ventricular vent was passed through the right superior pulmonary vein and the heart was then offloaded. 

Cerebral protection was achieved by deep hypothermic circulatory arrest combined with selective antegrade cerebral perfusion. Once the nasopharyngeal and bladder temperatures reached 25 degrees Celsius, the patient was positioned head down, CPB was terminated, and the patient’s blood volume was emptied out into a reservoir. The ascending aorta was then transected. Diastolic arrest was achieved with retrograde cardioplegia delivery. Distal organ protection was achieved with deep hypothermic circulatory arrest. An atraumatic vascular clamp was applied to the base of the innominate artery, bilateral cerebral perfusion was initiated via the right axillary cannulation and direct left common carotid artery cannulation.

Next, the distal aortic reconstruction between proximal aortic arch and an Anteflo graft was performed using a 3-0 running Prolene suture and was reinforced with pledgeted 4-0 Prolene sutures where necessary. The graft was then deaired and the aortic reconstruction was inspected for hemostasis. A full-body perfusion via the right axillary artery and rewarming towards 37 degrees centigrade were initiated. This marked the end of deep hypothermia circulatory arrest for distal organ protection. Cerebral saturation was maintained at a satisfactory level throughout the procedure. 

The aortic valve was then resuspended at each commissure. An end-to-end anastomosis between the Anteflo graft and the SJT was performed using a 3-0 running Prolene suture and was reinforced with a second layer of pledgeted 4-0 Prolene sutures.

Once the body was warm, the patient was weaned from CPB uneventfully. Hemostasis was carefully checked, and Protamine was given to reverse the heparin effect. Postprocedural transesophageal echocardiography showed adequate regional wall motion and valvular function. The patient had a complete and uneventful postoperative recovery.

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