Cerebral hyperperfusion syndrome (CHS) is a rare but potentially fatal risk of carotid endarterectomies and carotid artery stenting. These are surgeries that are used to increase blood flow in the carotid arteries, the major vessels that supply blood to your neck, brain, and face.
CHS can lead to swelling and bleeding in your brain. The mortality rate is as high as
The term “CHS” is often used interchangeably with “cerebral reperfusion injury” or “reperfusion syndrome.” Read on to find out more about what causes CHS and how it’s managed.
“Hyperperfusion” is the medical term for increased blood flow through an organ. The prefix “hyper” means increased or excessive, and “perfusion” refers to the passage of blood through a blood vessel.
Cerebral hyperperfusion is defined as a greater than 100 percent increase in blood flow through the carotid artery compared with baseline. Some people develop symptoms with increases in blood flow as small as 20 to 40 percent.
CHS is a potential risk of carotid arterial revascularization surgeries. These surgeries aim to increase blood flow through the carotid artery to prevent strokes in people with carotid artery disease. Blockages in the carotid arteries account for 15 percent of all strokes.
CHS was first discovered to be a risk of a type of surgery called a carotid endarterectomy, but it can also occur after carotid artery stenting. It can develop immediately after surgery or up to a month later.
The exact reason why some people develop CHS remains unclear. Multiple factors are thought to contribute.
Loss of autoregulation
Normally, your brain autoregulates itself to maintain a constant pressure when blood flow changes.
When blood flow increases after surgery, the brain may not constrict blood vessels appropriately to protect beds of tiny blood vessels called capillaries.
Chronic high blood pressure
People with a severe narrowing of the carotid artery often have chronic
Nitric oxide and free radical damage
Nitric oxide is a vasodilator, meaning that it relaxes blood vessels and allows more blood to pass through.
Baroreceptors are specialized receptors that sense blood pressure and send signals to your brain to either upregulate or downregulate blood flow. During surgery, the nerves that carry information from these receptors can become damaged. This damage can lead to increased blood pressure that’s hard to control even with medication. Fluctuations in blood pressure due to baroreceptor damage can last for up to
Most people with CHS have mild symptoms, but they can progress to severe and life threatening if left untreated. The most common symptoms are:
Less common symptoms include:
- focal neurological deficit (problem with brain function in a particular location)
- loss of consciousness
- blurred vision
This condition can be fatal in some instances.
CHS is a rare risk of carotid surgery. One
What can increase the risk of getting CHS?
Large studies have found that the three most common conditions associated with the development of CHS are:
- a more than 90 percent blockage of the carotid artery
- severe clogs (or plaques) of the blood vessels in the brain
- longstanding preexisting high blood pressure
Studies have also identified the following as risk factors for developing CHS after carotid surgery:
- being assigned female at birth
- chronic kidney disease
- left sided carotid disease
- progressive neurological disorders
- recurrent hemorrhages (bleeding)
- brain lesions (tumors or damaged areas)
- microvascular disease (disease of the small blood vessels)
- reduced ability of the blood vessels in the brain to respond to changes in blood flow
What risks does CHS pose to your health?
If left untreated, CHS can lead to severe brain swelling, bleeding, permanent disabilities, or death.
A 2018 review of studies noted that 47 percent of CHS cases led to stroke and that more than half of strokes were fatal or disabling.
Treatment for CHS often includes intravenous medications to lower blood pressure, such as labetalol and clonidine.
Seizure medications may be given to prevent seizures or to treat seizures if they occur.
Mannitol and hypertonic saline may be used to treat brain swelling. However, whether these treatments are effective in the long term
Surgery may be required if bleeding occurs.
Taking steps to keep your blood pressure in a healthy range may help you prevent CHS, since high blood pressure is considered a risk factor for its development.
Quick identification and treatment of CHS are critical for preventing potentially lethal complications. It’s recommended that blood pressure should be monitored by healthcare professionals continuously at least every 15 minutes for 24 hours or more after surgery.
CHS management focuses on reducing swelling, seizures, and bleeding, which are the main causes of brain damage.
In the early stages, swelling is usually reversible, but if it progresses to a hemorrhage, the outlook isn’t as favorable. Up to
CHS is a rare risk of surgeries used to increase blood flow in the carotid artery. It’s defined as a more than 100 percent increase in blood flow through the carotid artery from baseline.
CHS can lead to severe complications such as permanent disability or death. Early recognition of CHS is critical for receiving prompt treatment. Common initial symptoms include headaches, face pain, or eye pain on one side. Get immediate medical attention if you experience any of these symptoms within a month of carotid surgery.