Aortic Arch Replacement Procedure—Extended Aortic Arch Replacement Through the L-Incision Approach

Skin incisions for the L-incision approach and for arterial cannulation of the bilateral axillary arteries are shown. The skin incision is extended to the left anterior axillary line, and usually the 5th intercostal space (ICS) is used for the thoracotomy. A double-lumen endotracheal tube is routinely used to permit deflation of the left lung during the distal anastomosis. With a patient in either supine or left anterolateral position, a left anterior thoracotomy is made through the 4th to 6th ICS, and thereafter, an upper half median sternotomy is performed. Patient position depends on how the descending aortic aneurysm goes down. When the descending aorta goes down more medially than usual, the patient should be in the left anterolateral position with 30- to 45-degree rotation. The intercostal muscles are divided widely as much as possible to prevent rib fractures. The left internal thoracic artery is ligated and divided.

In principle, the systemic arterial perfusion is delivered through the cannulae inserted into the axillary arteries.³ An 8-mm Hemashield graft (Hemashield Gold; Meadox Medicals, Inc., Oakland, NJ) is anastomosed in an end-to-side fashion to the axillary arteries for arterial perfusion. The graft anastomosis is performed instead of direct cannulation to obtain a large bore size for the arterial perfusion line and to prevent vascular injury including arterial dissection. When the intraoperative epiaortic echography reveals no significant atheromatous plaque on the ascending aortic wall, the ascending aorta can also be used as an alternative cannulation site. The right or left femoral artery is always exposed, and a 10-mm Hemashield graft is anastomosed on it only for lower systemic perfusion during arch vessel reconstruction. We avoid perfusing the arch vessels via the femoral artery because retrograde aortic perfusion carries the risk of cerebral embolism.⁴

The operative view through the L-incision approach is shown. Two spring retractors (Kent-boomerang/spring retractor; Takasago, Tokyo, Japan) are placed to obtain an adequate operative field; one retracts the left half of the sternum in a left cranial direction and the other retracts the right half of the sternum in a right caudal direction. An adequate operative field for the ascending aorta, three arch vessels, innominate vein, and right atrial appendage can be obtained through this approach. The superior vena cava, which is used for retrograde cerebral perfusion, can also be accessible. When a surgical table is rotated to a surgeon and the lung is retracted to the medial side, the entire descending aorta can be observed in selected cases.

A two-stage venous cannula is inserted through the right atrial appendage, and cardiopulmonary bypass is established. In L-incision approach, a left ventricular venting tube can be inserted from the left upper pulmonary vein, the roof of the left atrium, or the left atrial appendage. Of these, the left upper pulmonary vein is the most preferable site. Thereafter, systemic cooling is initiated; exposure of the ascending aorta, arch, arch vessels, and descending aorta is obtained, and vascular tapes are placed around them. The fat pad containing the vagal and phrenic nerve is identified and isolated by a piece of tape.

A proximal anastomosis (graft to the ascending aorta) using a sealed graft with four branches (Hemashield Gold; Meadox Medicals, Inc.) is performed while cooling to 25°C rectal (or urinary bladder) temperature with cardiopulmonary bypass. After confirming with epiaortic echography that there are no plaques in the ascending aorta, aortic cross-clamping is performed, and antegrade cardioplegia is administered. The epiaortic echography is routinely used. We believe that the epiaortic echo is an essential tool for preventing catastrophic brain damage due to dislodging of the atherosclerotic plaque on the ascending aorta because preoperative computed tomographic scanning might pass away the small soft plaque occasionally.

When the epiaortic echography reveals atheromatous plaques on the ascending aorta, core cooling to 25°C is performed, and the tourniquets around both the brachiocephalic and the left subclavian arteries are tightened. Thereafter, the ascending aorta is transected after lower body circulatory arrest. We start selective cerebral perfusion using a 12-Fr perfusion catheter placed into the left carotid artery. Care must be taken not to dislodge the soft plaque that is frequently seen at the orifice of the left carotid artery. Crystalloid cardioplegia is directly infused into the left and right coronary arteries. Next, the descending aorta is clamped, and lower body perfusion is instituted through the femoral artery. One pump circuit is used for bilateral axillary arteries and femoral artery. The perfusion pressure is maintained at around 60 mm Hg as measuring in the opposite site of the femoral artery. As the perfusion rate for each vessel is not monitored, care must be taken not to kink the arterial line.

Immediately after proximal anastomosis, the heart is reperfused from one branch of the graft. Next, three arch vessels are reconstructed, one by one, from the left subclavian artery, left carotid artery, and brachiocephalic artery.

After completion of arch vessel reconstruction, the antegrade cerebral flow is restored from the graft.

Then the left lung is deflated for adequate exposure of the descending aorta, and we perform the distal anastomosis. The surgical table is rotated 30° from supine toward the patient's right side, and the operator moves from the patient's right side to left side. The open distal anastomosis using elephant trunk technique can be done safely under direct vision. Care must be taken to check bleeding from the intercostal arteries and branch vessels to the esophagus and bronchus. Deep bite of suturing for hemostasis from the inside of the aorta should be performed carefully, not penetrating the esophagus, which is located closely to the aorta. The left lung should be manipulated gently to prevent postoperative pulmonary dysfunction.

Regarding the distal anastomosis, we use two techniques. One of them is shown in this figure: that is, a modified elephant trunk technique.⁵ After ceasing lower systemic perfusion, the folded graft is inserted into the descending aorta. Then, over-and-over sutures are made and the graft is pulled out. To reinforce the anastomosis, we routinely perform double running sutures. As this anastomosis is being completed, perfusion through the femoral arterial line is reestablished to remove air and debris.

If the descending aorta is too small to put the folded graft in, a straight unfolded graft is inserted into the descending aorta.⁶ After double running suture technique is performed, the graft is reversed and pulled out. Occasionally, a modified elephant technique for a small descending aorta causes stenosis at the anastomosis.

After completion of the distal anastomosis, we initiate systemic rewarming. During the open distal anastomosis, the rectal temperature is maintained at 25°C to protect the spinal cord. The previously anastomosed graft to the ascending aorta and arch vessels is passed down through the opening under the pedicle containing the vagal and phrenic nerves. Then, the graft-to-graft anastomosis (between the four-branched graft and the graft to the descending thoracic aorta) completes the operation. Total arch replacement with extended replacement of the descending aorta can be easily performed through the L-incision approach.