surgery for aortic dissection
Surgery for Aortic Dissection
At Max Cardiac Surgical Centre in Patparganj, doctors and surgeons collaborate to quickly determine the best treatment for an aortic dissection, which is a tear in the wall of the aorta, the largest artery in the body. Because some types of aortic dissections require emergency surgery, our experts work to accurately diagnose the condition and determine the best treatment as quickly as possible.
We are highlighting this fatal condition, as Max Patparganj is one of the very few centres in the country that runs a 24×7 Aortic dissection service. The cardio vascular team lead by Dr. Ritwick has performed a large number of such complex procedures with excellent outcome.
Treatment for aortic dissection may include medication or surgery.
Types of Aortic Dissection:
The aorta—a candy cane–shaped blood vessel originating in the chest at the top of the heart and extending into the abdomen—is the largest artery in the body. Like other arteries, it carries oxygen-rich blood from the heart to the rest of the body. The walls of the aorta consist of three layers that give it strength.
An aortic dissection or tear in the aorta typically occurs when the inner layer of the artery’s wall weakens. A small tear forms in this layer and if left untreated, it can enlarge.
Blood can pass through the tear into the middle layer of the wall, causing the layers to separate from one another or dissect. This can lead to the formation of a new channel, called a false lumen, between the two layers. This false lumen can extend from the tear to the lowest part of the aorta, preventing blood from flowing properly to the rest of the body.
The separation of the inner layer of the aorta forms a flap or septum, which can have multiple holes; known as re-entry tears, that have a Swiss cheese appearance. These tears allow blood to flow between the true lumen or natural passageway and the false lumen. If the flap doesn’t peel away from the aorta, blood can pool in the false lumen.
Over time, the blood in the false lumen can back up and clot, cutting off blood flow to other organs and further weakening the aortic wall. Sometimes, the blood breaks through the outer layer of the aorta, causing a life-threatening loss of blood and drop in blood pressure that requires immediate surgery.
Aortic dissection can lead to serious complications including; heart attack, kidney failure, stroke, paralysis, and intestinal ischemia in which blood vessels to the intestines becomes blocked. It can also cause lower extremity ischemia or blockages in the blood vessels of the legs.
Because the risks and appropriate treatments can be markedly different depending on the type of aortic dissection, it is crucial to accurately diagnose this condition. The type of aortic dissection is based on the location of the tear and the duration of the symptoms. There are two types of aortic dissection, Type A and Type B.
Type A Aortic Dissection
If the aortic dissection occurs in the ascending aorta, the curved part of the aorta that extends upward from the heart, it’s called a Type A aortic dissection. A Type A tear may extend along the upper part of the aorta and down toward the abdomen.
Type A is more common than Type B. It’s also more dangerous, because it’s more likely to cause the aorta to rupture, leading to a potentially fatal heart condition.
Although this type of dissection sometimes causes no symptoms, it is more often accompanied by shortness of breath and a sudden, severe, sharp pain that feels like a tearing in the chest and upper back. It requires immediate surgery.
Type B Aortic Dissection
A Type B aortic dissection originates in the descending aorta, which extends from the arch at the top of the ascending aorta—the part that extends upward from the heart—in the chest to the bottom section of the aorta, also known as the abdominal aorta.
This type of dissection is usually treated with medications and monitoring by a doctor, because it rarely causes life-threatening side effects. Occasionally, Type B dissections can reduce or block blood flow to organs, such as the kidneys and the intestines, requiring surgery.
Symptoms may include high blood pressure and a severe, sharp back pain that can feel like it is extending into the chest or abdomen.
Acute Aortic Dissection
Both Type A and Type B aortic dissections are further diagnosed by doctors as being either acute or chronic. The majority of aortic dissections are acute, meaning the tear causes symptoms immediately and can be life threatening.
Types of Aortic Dissection
Acute aortic dissection causes sudden chest or back pain or both. Because the condition can lead to a rupture of the aorta, it requires immediate medical attention, usually surgery.
Chronic Aortic Dissection
Sometimes symptoms of an aortic dissection are vague and nonspecific and may go unnoticed until the tear begins to cause other complications. When these symptoms occur, or if imaging tests show signs that the condition has been present two weeks or longer, it is called chronic aortic dissection. Most chronic aortic dissections are Type B.
After you receive a diagnosis, your doctor monitors the chronic dissection with CT scans or a type of MRI scan called a magnetic resonance angiogram. These imaging tests can reveal a rapid expansion of the aorta, which can signify a blood clot or an aortic aneurysm, in which the aorta bulges, necessitating surgery. Medications are often prescribed to help reduce the flow of blood against the aortic wall.
Surgeons either insert a tube called a stent to prevent blood from flowing into the false lumen that forms between the layers of the aorta during a dissection, or they replace the damaged parts of the aorta with a synthetic material.
Although most Type B aortic dissections are treated with medication, you may need surgery if you develop ischemia, a condition in which the dissection prevents the flow of blood to certain organs or to the legs.
Your doctor may recommend endovascular surgery to remove the blockage. In this minimally invasive procedure, the surgeon makes small incisions in the groin to access the femoral artery in the leg, which allows the doctor to reach the aorta. If necessary, small incisions can be made in the chest instead of the groin.
A thin wire is advanced through the artery and to the area near the aortic dissection, always staying within the true lumen, or natural passageway, of the aorta. The surgeon fits a thin tube called a sheath over the wire, slides it to the location of the dissection, and withdraws the wire.
He or she then guides a stent graft, a fabric tube covered with a metal mesh, through the sheath to the dissection. The surgeon expands the stent graft to fit the diameter of the aorta.
The stent supports the aorta, allowing it to heal by cutting off the blood flow to the false lumen, which is a new channel for blood flow that was created by the tear in the aortic wall. It also reinforces the aorta and can therefore prevent an aortic aneurysm or bulging of the aortic wall from developing in the weakened aorta.
Sometimes, the surgeon uses a “fenestrated” stent graft, which is customized to fit the person’s aorta and has specifically placed holes or fenestrations that allow blood to flow to the arteries that lead to important organs, such as the kidneys. This device allows the surgeon to repair the aorta without affecting blood flow, even if the dissection is located near important arterial branches that supply blood to vital organs.
Recovery from endovascular surgery is significantly quicker than that from open surgery. You can expect to remain in the hospital for two to three days after surgery. Because your aorta and heart need rest to heal, your doctor may recommend that you refrain from driving and lifting anything heavier than 10 pounds for 10 days after surgery.
Open Heart Surgery
Type A aortic dissections are located in the ascending aorta, the part that exits the heart. These typically require emergency surgery—as do dissections involving the arch that forms the top of the aorta—because the dissection can split open or “unzip” the aorta.
This can cause bleeding into the pericardium, the sac-like membrane that envelops the heart, or into the abdomen. This bleeding can lead to cardiac tamponade, a potentially fatal condition in which the blood accumulating in the pericardium puts pressure on the heart, preventing it from working properly.
In open heart surgery, the surgeon makes a large incision in the chest and opens the sternum or breastbone, with surgical tools. Then he or she sutures or sews together, the “flap” which is the partition between the layers of the aortic wall created by the dissection.
Sections of the aorta are replaced with a synthetic material called Dacron®, which usually lasts a lifetime. Prior to the procedure, surgeons give you a nutrient-rich solution intravenously that safely slows the heart until it’s nearly stopped to allow for surgery.
Because open heart surgery is a complex procedure, it can lead to serious complications. You can expect to remain in the intensive care unit for several days after surgery. This allows your doctor to monitor you for signs of internal bleeding, heart attack, kidney failure, infection, and ischemia; a condition in which organs, such as the kidneys, are deprived of oxygen-rich blood.
Stents may also be implanted during open surgery to repair Type A aortic dissections.
After you return home, your doctor may advise you not to drive for 1 to 2 weeks and to avoid lifting anything heavier than 10 pounds for 4 to 6 weeks. This is because your aorta and heart require rest and time to heal.
You may have a CT scan or MRI scan after surgery to ensure that your aorta is healing properly. Your doctor may prescribe a medication called a beta blocker to control your blood pressure.