The aorta is the largest blood vessel in the body, through which blood flows to the rest of the body from the heart. It begins from the chest, that is, the thoracic aorta, to the abdomen, the abdominal aorta, which takes blood to the intestines, kidneys, and the liver. Below the abdomen, it divides into iliac arteries, from which each leg receives blood.
An aortic aneurysm refers to a dilation of the aorta from the typical diameter of two centimeters to almost twice its size, which is about five centimeters and above. It is a thin weakened section of the aorta that bulges outward weakening the artery wall. If it remains untreated, it may rupture leading to massive bleeding and is often fatal.
Abdominal aortic aneurysm (AAA) is repaired through classical opening or endovascular repair also referred to as stent grafting. The process involves inserting a graft mounted on slender metal tubes also referred to as stents. The surgery is aimed at repairing an aneurysm in the aorta so as to prevent it from bursting.
The surgery is undertaken at the UW Health, Heart, Vascular and Thoracic Centre located in Madison, Wisconsin. There are about eight people in the operating room, five of whom are vascular surgeons and one of them is the host of the webcast. In addition to the surgeons, are two assistants and a nursing professional. A radiologist is also present to assist with imaging.
Dr Jon, Matsumura, the host of the show explains that there is presently no cure for abdominal aortic aneurysms; therefore Endovascular AAA Repair (EVR) is significant in cases where a patient has a bulging aorta. An advantage of the stent grafting compared to the open heart surgery is that it is less invasive in that the incision made is small as opposed to an incision on a larger part of the abdomen. Moreover, the patient experiences lesser blood loss and has a quicker recovery. He introduces Dr.Hoch, who gives a brief history of the patient and introduces the rest of the medical staff to be involved in the surgery.
Dr. Hoch describes the patient as a 64 year old male, who has chronic destructive pulmonary disease and thus is oxygen dependent. He has a history of arterial fibrillation, morbid obesity, adult onset diabetes mellitus, is hypertensive and hyperlidemic and quit smoking in 2007. He explains that the patient’s discovery of aortic aneurysm was during an MRI of the spine.
Dr. Tefera takes up the first phase of the endovascular aortic repair and begins with examination of a CT scan that had been performed earlier. It is manipulated to demonstrate a 3D imaging of the aorta. He explains that incisions, although not large, have been made in the groin area of the patient so as to expose the femoral arteries. The surgery preparation involves placing of a sheath through the femoral arteries to allow access of the graft material. The sheath is placed in the opening to keep the artery open and control bleeding.
An arteriogram is used to show the landmarks to assist in the positioning of the stent graft. A Percutaneous delivery device is inserted through the femoral artery, into which a guide wire is passed to the site of the aneurysm. The Percutaneous device is then removed and a sheath is passed over the guide wire by use of a pro-glide device.
The surgeons perform an angiogram enables the surgeons to visualize the position of the aneurysm and the adjacent blood vessels. Therein, they identify the right and left renal artery and the renal vein. They use this to calculate the diameter of all the necessary vessels that will be involved in the aneurysm repair. This ensures that all the devices inserted into the aneurysm are well placed.
An intravascular ultrasound is employed to determine the extent of the aneurysm in the patient. Using the images presented by the fluoroscopy, a cathereter is positioned and the surgeons take note of the measurements that will determine the correct position of the stent graft. The Catheter can be spotted as it is placed up inside. The Aorta should have a narrow enough area so that the graft can withstand the resistance of the aneurysm and does not lead to leaking. Hence forth the procedure entails a multi- step positioning of the stent graft. The graft opens up into the aorta and a check is performed to ensure that there is no damage on the kidneys. The origin of the renal artery can be seen as they move the device upwards so that it rests on the exact position that it should be (http://orlive.uwhealth.org/videos/endovascular-repair-for-aortic-aneurysms).
An opening for the guide wires is made on the other leg. There is emphasis that the wire should be inside the graft and not behind it. In essence, all the devices necessary have been deployed at this point. The most essential issue is the stent graft to be well sitted. A balloon device is used to ensure that all wrinkles present are smoothened out and that the stent is placed close to the arterial wall. The stent graft is relatively short, thus extension grafts are deployed to cover the iliac arteries. The sheath is used as a dilator to enable the balloon to pass over the wires. Ballooning is therefore necessary to seal the overlapping extensions so that blood does not flow out of the aneurysm.
Lastly, an angiogram is performed to make sure that there is no endoleak. The devices used during the procedure are removed and the sheath is taken out. Afterwards groin area of the patient is stitched. The surgeon then pulls out the switcher and the procedure is complete. There is minimal bleeding of the patient after the surgery.