Overview of Carotid Endarterectomy
When fatty substances, or plaque, build up in the carotid artery (the main blood vessels in the neck that supply blood to the brain), this can lead to a disease known as atherosclerosis. This can make the artery narrower, a condition called stenosis. Sometimes, this may not cause any noticeable symptoms, but it can significantly increase the chance of stroke or other diseases related to the blood vessels in the brain.
One way to reduce this risk is a surgical procedure known as carotid endarterectomy (CEA). This surgery involves removing the plaque from the carotid artery, helping to improve blood flow to the brain and removing any material that could potentially block these blood vessels. By doing this, the surgery helps restore a more normal flow of blood to the brain. Surgeons have been performing reconstructions of the carotid artery since the early 1950s, and techniques for CEA, as well as the reasons to do this surgery, have continued to develop over time.
Anatomy and Physiology of Carotid Endarterectomy
The aorta is a major blood vessel, and within the upper part of the space in the chest cavity, it forms an arch at the spot where the breastbone meets the middle rib bones. From the aorta, three big blood vessels emerge: the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery.
On the right side, the common carotid artery branches from the brachiocephalic trunk. Additionally, both left and right common carotids split into an internal and an external carotid artery, usually at the level of the fourth neck bone, near the top edge of a flexible piece of cartilage in the neck known as the thyroid cartilage.
The carotid arteries, internal jugular veins, and vagus nerves are wrapped in a thick layer of dense connective tissues called the deep cervical fascia to form what we know as the carotid sheath. These systems are located towards the middle of the sternocleidomastoid muscle, a significant neck muscle that allows rotation and flexion of the head.
The internal carotid artery then proceeds into the skull where it becomes part of the Circle of Willis, a circular network of arteries located at the base of the brain. This system provides blood to the brain and eyes. The external carotid artery has blood vessels branching from it providing blood to the neck and face.
Why do People Need Carotid Endarterectomy
In 1987, a study called the North American Symptomatic Carotid Endarterectomy Trials (NASCET) began. This study helped doctors understand how to treat a patient with different degrees of carotid stenosis, a condition where one of the main blood vessels supplying blood to the brain (the carotid artery) becomes narrow and restricted.
The study found that surgery had a significant benefit for people with severe carotid stenosis, where the blood vessel is more than 70% blocked. No significant benefits were found for those with less than 50% blockage. Based on this study, the current guidelines for doctors suggest surgery for patients who have at least 50% blockage and who have had symptoms of a stroke or a mini-stroke (known as transient ischemic attack or TIA).
Symptoms might include temporary loss of vision, weakness on one side of the body, facial weakness, or speech loss.
Another study examined patients who didn’t show any symptoms, but were known to have diseased carotid arteries. Here they found that patients with severe blockage who underwent surgery had a significant drop in their risk of stroke in the following five years. As a result, such patients are also now encouraged to have the surgery.
Since medical treatments have improved since the 1980s, a new study is underway. It aims to compare how well medication versus surgery works in patients who have a high degree of carotid stenosis but no symptoms.
Doctors can find these patients by using a type of ultrasound scan, called carotid duplex ultrasonography (CDU). CDU can measure the narrowness of the carotid artery and observe the blood flow. Other forms of imaging, like computed tomography angiography (CTA) and contrast-enhanced magnetic resonance angiography (CE-MRA) can also be used. These techniques help to look at different factors like plaque build up and brain perfusion, which can affect the risk levels of the patient.
For those showing symptoms and having significant carotid blockage, the surgery must be done soon after the onset of symptoms to be of use. If performed within two weeks of symptom onset, the surgery is effective in preventing a stroke in every fifth patient. However, the surgery is beneficial only when the symptoms aren’t disabling, and there are no other major health concerns.
A different procedure, called Carotid artery stenting (CAS), where a wire mesh tube is used to open up the blocked artery, is preferred in cases where the patient has other health complications, or if they’ve previously received neck radiation or had a neck dissection. While it carries a slightly higher risk of stroke during the procedure, their outcomes are mostly similar to those treated with surgery. The effectiveness of CAS is also being studied in the ongoing research.
When a Person Should Avoid Carotid Endarterectomy
People who are very sick and can’t have traditional surgery might be candidates for a procedure called carotid angioplasty and stenting (CAS). In this procedure, a small flexible tube, like a mesh, is inserted into the artery while the person is awake but numbed. This tube is opened up over a balloon to expand the blood vessel and increase blood flow.
A major study showed that this procedure and another one called carotid endarterectomy (CEA), which involves removing plaque from the artery, have similar rates of complications after surgery, like blood vessel narrowing again, heart attack, long-term stroke, and death. However, people who have the CAS procedure may have a higher risk of having a stroke during the procedure. On the other hand, the overall risk of having a heart attack is higher in people who have the CEA procedure.
Patients who have had radiation therapy to the neck may face a higher risk of temporary injury to the nerves in the head during CEA, and also have an increased risk of late events like stroke and blood vessel narrowing following CAS. CEA can be more difficult in patients who have had radiation to the neck because these patients tend to have more diffuse plaques throughout the artery, as well as adhesions, scar tissue, and wound complications because of the radiation.
Women who have symptoms may face a higher risk of complications after CEA compared to men. However, for patients without symptoms, both men and women have similar outcomes and complications.
Preparing for Carotid Endarterectomy
Before having a procedure called a carotid endarterectomy, which is a surgery to remove blockage from the carotid arteries in the neck, patients are generally asked to take antiplatelet medication, unless a doctor advises not to. Antiplatelet medication helps prevent blood clots.
This surgery can be done under general anesthesia, which means the patient is fully asleep, or local anesthesia, where only the area of the surgery is numbed and the patient is awake but relaxed. With local anesthesia, the patient won’t feel any pain in the area where the surgery is being done.
Then, for safety and to prevent infection, the patient’s neck, including the jaw and earlobe, is covered with a sterile drape after it has been cleaned. This preparation helps ensure the surgery goes smoothly and reduces the risk of infection.
How is Carotid Endarterectomy performed
Carotid endarterectomy, a type of surgery to unclog a carotid artery, has two common techniques: the traditional method and the eversion method.
Traditional Method
In the traditional method, the surgeon makes an incision along the side of the neck muscle, cutting through layers of fat and the platysma muscle, which is a thin layer of muscle covering the front of the neck. The surgeon then carefully cuts through the cover around the blood vessels in the neck, revealing the carotid arteries. The surgeon then temporarily clamps the carotid artery on either side of the plaque, which is essentially a fatty deposit, to stop blood flow momentarily. The surgeon then opens the length of the artery and locates both ends of the plaque. The clamps are released one at a time and a flexible tube, a bypass stent, is inserted to maintain blood flow around the surgical area as the blockage is removed. To repair the artery, a patch is used to widen the artery and the stent is taken out. The patch material can be from one’s own vein, from a cow, or from synthetic materials. Once the artery is fixed, the surgeon checks that the blood flow is good using ultrasound or angiography.
Eversion Method
In the eversion method, the surgeon cuts the carotid artery at the point where the two branches of the artery meet. The artery wall is turned inside out, like turning the finger of a glove inside out, around the plaque, and the blockage is cut away and removed. Afterward, the artery is repaired by sewing the two ends back together. This method is sometimes preferred as it doesn’t require a patch and the overall surgery may take less time.
Possible Complications of Carotid Endarterectomy
How well a surgery goes and what happens afterward can depend on many things. It can depend on how skilled the surgeon is and their methods, the patient’s health, and how well the patient is cared for before and after the operation.
When undergoing a carotid endarterectomy (CEA), a surgical procedure to remove plaque from the carotid artery (the main blood supply to the brain), there can be both major and minor complications.
Major complications can include:
– Myocardial Infarction, which is a fancy name for a heart attack.
– Hyperperfusion syndrome, a condition where too much blood flows into one part of the body.
– Nerve Injury, specifically damage to the cranial nerves. These could be the hypoglossal (tongue movement), vagus (controls various organ functions), glossopharyngeal (throat and taste), and facial nerves (controls facial muscles and sensations).
– Perioperative stroke, which means having a stroke during or just after the surgery.
– Restenosis, which is when the artery that was opened narrows again.
– In worst cases, death is also a possibility, although rare.
Minor complications can include:
– Transient Ischemic Attack, which is like a mini-stroke that goes away quickly but could be a warning sign of a bigger stroke.
– Bleeding, which is a typical risk in any surgery.
– Infection, which can be a risk with any kind of surgery.
– Greater Auricular Nerve Injury, which could impact sensation around the ear.
– Dysphagia, or trouble swallowing.
These are not guaranteed to happen, but they are possibilities to be aware of. The doctor will do everything they can to prevent these from happening and to treat any that do occur.
What Else Should I Know About Carotid Endarterectomy?
A carotid endarterectomy is a surgery that works to prevent strokes and improve a person’s health and quality of life. A stroke happens when blood flow to your brain is interrupted. This surgery helps by removing the build-up from the carotid arteries, the main blood vessels that deliver blood to your brain. These blockages can reduce blood flow or potentially cause a stroke.
It’s been proven that this surgery significantly decreases the chances of having a stroke in patients who have moderate to severe carotid disease: a condition where these blood vessels become narrowed or blocked. This procedure can also increase one’s chances of survival and promote a healthier life.
