Cerebral hyperperfusion syndrome (CHS) is a rare but life-threatening risk of carotid endarterectomies and carotid artery stenting. These are surgical procedures that are used to increase blood flow in the carotid arteries, the main vessels that supply blood to the neck, brain and face.
CHS can cause swelling and bleeding in your brain. The death rate is as high as
The term “CHS” is often used interchangeably with “reperfusion brain injury” or “reperfusion syndrome.” Read on to learn more about the causes of CHS and how it is managed.
Meaning of “hyperperfusion”
“Hyperperfusion” is the medical term for increased blood flow to 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 an increase greater than 100% in blood flow in the carotid artery compared to baseline. Some people develop symptoms with an increase in blood flow as low as 20-40%.
CHS is a potential risk of carotid artery revascularization surgeries. These surgeries aim to increase blood flow in the carotid artery to prevent strokes in people with carotid artery disease. Blockages in the carotid arteries account for 15% of all strokes.
CHS was first discovered as a risk of a type of surgery called carotid endarterectomy, but it can also occur after stenting the carotid artery. It can develop immediately after surgery or up to a month later.
The exact reason why some people develop CHS remains unclear. Several factors are thought to contribute to this.
Loss of self-regulation
Normally, your brain regulates itself to maintain constant pressure when blood flow changes.
When blood flow increases after surgery, the brain may not constrict blood vessels appropriately to protect the beds of tiny blood vessels called capillaries.
Chronic high blood pressure
People with severe narrowing of the carotid artery often have
Damage caused by nitric oxide and free radicals
Nitric oxide is a vasodilator, which means it relaxes blood vessels and lets more blood flow through.
Dysfunction of baroreceptors
Baroreceptors are specialized receptors that sense blood pressure and send signals to your brain to up-regulate or down-regulate blood flow. During surgery, the nerves that carry information from these receptors can be damaged. This damage can lead to increased blood pressure that is difficult to control, even with medication. Fluctuations in blood pressure due to baroreceptor damage can last up to
Most people with CHS have mild symptoms, but they can progress to severe and life-threatening symptoms if left untreated. The most common symptoms are:
Less common symptoms include:
This condition can be fatal in some cases.
CHS is a rare risk of carotid surgery. A
What can increase the risk of getting CHS?
Extensive studies have revealed that the three most common conditions associated with the development of CHS are:
- more than 90% blockage of the carotid artery
- severe blockages (or plaques) of blood vessels in the brain
- long-standing pre-existing high blood pressure
Studies have also identified the following as risk factors for developing CHS after carotid surgery:
- to be assigned female at birth
- chronic kidney disease
- left carotid disease
- progressive neurological disorders
- recurrent hemorrhaging (bleeding)
- brain damage (tumors or damaged areas)
- microvascular disease (disease of small blood vessels)
- reduced ability of 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 disability, or death.
A 2018 review of studies noted that 47% of CHS cases resulted in stroke, and more than half of strokes were fatal or disabling.
Treatment for CHS often includes intravenous drugs to lower blood pressure, such as labetalol and clonidine.
Antiepileptic drugs may be given to prevent seizures or to treat seizures if they occur.
Mannitol and hypertonic saline solution can be used to treat brain swelling. However, if these treatments are effective in the long term
Surgery may be needed if bleeding occurs.
Taking steps to keep your blood pressure within a healthy range can help prevent CHS, as high blood pressure is considered a risk factor for its development.
Prompt identification and treatment of CHS is essential to prevent life-threatening complications. It is recommended that blood pressure be monitored by medical professionals continuously at least every 15 minutes for 24 hours or more after surgery.
Management of CHS focuses on reducing swelling, seizures, and bleeding, which are major causes of brain damage.
In the early stages, the swelling is usually reversible, but if it progresses to hemorrhage, the outlook is not as good. Until
CHS is a rare risk of surgeries used to increase blood flow in the carotid artery. It is defined as an increase of more than 100% in blood flow in the carotid artery compared to baseline.
CHS can lead to serious complications such as permanent disability or death. Early recognition of CHS is key to receiving prompt treatment. Common early symptoms include headache, facial pain, or eye pain on one side. Seek immediate medical attention if you experience any of these symptoms within a month of carotid surgery.