Aortic Dissections Surgical Treatments

Treatment of type A dissection is often palliative (providing relief, but not a cure). The goal is to transform an acute type A dissection into a chronic type B dissection, thereby eliminating the risk from the most acute complications. A detailed description of the surgical procedure follows.

Once a type A dissection has been diagnosed, the patient is taken to the operating room and placed under general anesthesia. A TEE probe is placed and the extent of the dissection is assessed. (TEE or transesophageal echocardiography is an ultrasound imaging technique that uses a probe placed in the esophagus to take pictures of the heart and aorta.)

The surgeon first exposes the right axillary artery, which runs beneath the collarbone (clavicle), to confirm that it is not involved in the dissection. If the artery is intact, a tube graft is sewn to the artery and an end-hole cannula (tube) is placed, connecting the artery to the heart-lung machine. The breastbone (sternum) is then divided and the contents of the pericardium (sac around the heart) are examined to determine whether a rupture has occurred.

Once the pericardium is opened, a tube is placed to connect the right atrium to the heartlung machine. Bypass is begun and the patient's body temperature is cooled to 28°C. During this cooling period, the surgeon determines the extent of operation. The possibilities include:

1. Replacement of the ascending aorta and hemi-arch with a tube graft
2. Tube graft replacement plus repair of the aortic valve
3. Aortic root replacement plus aortic valve replacement with a mechanical valve
4. Aortic root replacement plus aortic valve replacement with a homograft
5. Total arch replacement with "elephant trunk" approach
6. Aortic root replacement plus total arch replacement

Once the heart has been stopped and carefully protected with cardioplegia, the innominate (brachiocephalic) artery is clamped and antegrade selective perfusion is begun. (Click here to learn more about antegrade perfusion for cerebral protection.) The undersurface of the aortic arch is removed and aortic continuity is re-established with bioglue and/or felt strips. The distal anastomosis (aortic opening furthest from the heart) is constructed with an appropriately sized Dacron graft.

The graft is then de-aired and clamped. Full flow and re-warming to 32° is begun. The aortic root is then assessed. All affected portions of the aorta are removed. If the aortic valve can be repaired, every effort is made to repair it. Often this will involve reattachment of the valve to the graft, a technique known as re-suspension. If the valve cannot be repaired, an appropriate valve replacement (tissue or mechanical) will be selected based upon the patient's age. After the root is properly reconstructed, the graft is de-aired and full rewarming completed. The patient is taken off the heart-lung machine and moved to the ICU for close monitoring.

Most important in initial management is the possibility of malperfusion syndrome—failure of the blood adequately circulate, potentially leading to organ failure. During the first several post-operative hours, urine output, fluid status, and laboratory values are carefully monitored. If there is any concern regarding blood flow to the organs, the patient is returned to the operating room for an abdominal angiography (imaging study). If required, a fenestration procedure can be performed endovascularly.