What is Cholesterol Emboli?
Cholesterol embolism, also known as atheroembolism, is a condition where cholesterol crystals and other materials like platelets and fibrin get dislodged from larger arteries such as the aorta, and travel to smaller, distant arteries. This usually happens when a cholesterol plaque in the artery breaks. If a patient experiences worsening kidney function, high blood pressure, sudden dysfunction in multiple systems, or reduced blood flow to distal body parts after an invasive arterial procedure, they might have cholesterol emboli. Most often, this condition occurs after procedures carried out in the arteries but it can also occur without any apparent trigger.
This condition is quite rare and can impact different organs, including the brain, muscles, skin, eyes, kidneys and the gastrointestinal tract. The organ damage is typically observed when cholesterol crystals breakaway from plaques in arteries and travel to other parts, causing blockage and inflammation in the target organ. It’s crucial to clarify that cholesterol embolism is different from thromboembolism. In thromboembolism, larger clots break away from plaques and cause sudden blockage, whereas cholesterol embolism is a slower process that ultimately damages the organs over time.
Cholesterol embolism is also known as “blue toe syndrome.” This variant of the condition occurs when the embolisms block the small arteries that supply the digital regions of the body. Despite the blockage, blood flow remains normal in the larger peripheral arteries. Hence, if someone has sores or blue discoloration in extremities like the toes, but normal blood flow, they might have “blue toe syndrome.”
What Causes Cholesterol Emboli?
Cholesterol emboli, or blockages in the bloodstream caused by cholesterol, have several risk factors, including:
- Being male
- Having high blood pressure
- Having high cholesterol levels
- Having diabetes
- Having diseases that affect the blood vessels in your legs and arms
- Having diseases that affect your main artery or the arteries in your lower body
- Having kidney failure
- Being over 60
- Having a stiffened heart valve
- Having a disease that affects your brain’s blood vessels
Patients who undergo procedures on their blood vessels or cardiovascular surgery are also likely to develop cholesterol emboli. People with an aortic aneurysm, or a bulging in the main artery of the body, have increased inflammation, which makes them more likely to have cholesterol emboli. Treatment options like blood clot dissolvers and anticoagulants can also increase the chances of developing cholesterol emboli. Lastly, the most critical risk factor is atherosclerosis, or the build-up of fats and cholesterol on the inside of your artery walls. The severity of atherosclerosis is directly linked to the likelihood of developing cholesterol emboli.
Risk Factors and Frequency for Cholesterol Emboli
Cholesterol emboli, or blockages, can happen on their own or after certain procedures on the arteries such as heart surgery or clot-breaking therapy. These blockages largely result from procedures carried out within the arteries, whereas quite a small percentage occur spontaneously.
It’s hard to pinpoint the exact rate of these emboli as it’s not always noticeable, but it’s thought to be under 3.5%. These blockages are more likely to happen in older patients with heart disease related to hardening and narrowing of the arteries.
Medical studies have shown that these emboli have occurred in between 10% to 77% of older patients who had arteries-related operations and then passed away. However, when looking at patients in general, studies found these blockages in only about 0.31% to 2.4% of cases.
It is important to mention that certain diseases and procedures can increase the chances of blockages by harden substances like cholesterol. These include:
- Aortic aneurysms (31% chance)
- Severe aortic disease (13%-16% chance)
- Repairing abdominal aortic aneurysm (can go up to 77% chance)
- Mild aortic disease (1%-2% chance)
Signs and Symptoms of Cholesterol Emboli
Cholesterol emboli are often found in patients who recently underwent procedures involving the blood vessels like heart catheterization, valve replacement, vascular stent placement, or carotid endarterectomy. People at risk for this condition typically have health issues related to heart disease and blood vessels. They may have a history with conditions such as coronary artery disease, high blood pressure, high cholesterol, stroke, mini-stroke, diabetes, abdominal aortic aneurysm, diseases of blood vessels outside the heart and brain, or kidney failure.
Patients with this syndrome often experience unclear symptoms such as fever, fatigue, weight loss, muscle soreness, and decreased appetite. Certain symptoms related to specific body organs may also manifest, most typically in the kidneys, skin, and gastrointestinal tract.
In the kidneys, cholesterol emboli cause injuries that can take a severe and immediate form or a lasting form. Immediate kidney injury from emboli shows up as red blood cells, eosinophils, and little protein in the urine test. The long-term form shows up as a lot of protein in the urine, similar to what is seen in nephrotic syndromes. If kidney disease is suspected due to these symptoms, cholesterol emboli syndrome should be considered as a possible cause, especially when the damage to the small filters in the kidneys is high.
When the gastrointestinal tract is affected, symptoms like stomach pain, side pain, back pain, gastrointestinal bleeding, blockage or death of parts of the intestine, spleen attack, pancreatitis, gallbladder inflammation, abnormal liver enzymes, and diarrhea may surface.
Skin-related symptoms include irregular purple skin spots, blue or purple toes, ulcers, gangrene, skin discolorations in a lacy pattern, small sores in the nail beds, and pain in the foot and toe. These are caused by non-inflammatory blockage of skin blood vessels due to cholesterol emboli, usually after procedures involving arteries.
Other issues linked to this syndrome include sudden blindness, temporary loss of vision or bright spots in vision, and plaques in the retina. With the involvement of the central nervous system, symptoms like headache, impaired consciousness, stroke, temporary ischemic attack, tingling, and spinal cord infarction may manifest.
Tests will usually show evidence of bodywide inflammation. A complete blood count may show low red blood cells, high white blood cells, and low platelets. Other potential findings include high eosinophils, low complement proteins, high amylase, lipase, lactate, LDH, ESR, and CRP levels. Urine tests may show varying amounts of red blood cells, eosinophils, and protein. Tests for kidney function may show evidence of ongoing or sudden kidney damage.
Testing for Cholesterol Emboli
No single lab test can definitively diagnose cholesterol emboli, also known as cholesterol embolization. But some basic lab tests, including a full blood count, a comprehensive metabolic panel, and a urine analysis, can offer helpful clues. In some cases, a patient might need a retinal exam, especially if they’re experiencing symptoms like brief visual loss or sudden blindness. This condition can only be confirmed with a biopsy, which involves taking a small sample from various organs like the skin, muscles, gut lining, bone marrow, or kidneys.
The way we examine and treat this disease can vary greatly, depending on the specific organ affected by cholesterol embolization. For instance, if a patient is showing symptoms similar to a stroke, a CT scan and MRI of the brain, along with an MRA of the head and neck, should be done.
If a patient comes in with a condition known as acute limb ischemia, then a CT angiogram might be needed urgently.
If there is a suspicion of bowel ischemia, lab tests should include serum lactate and a white blood cell count, which will probably be high. An abdominal CT scan should be performed, along with a potentially high-resolution CT angiography of the abdomen.
If there might be renal (kidney) emboli, a urine analysis should be done to look for protein and eosinophils. Lab tests should include a check for high levels of LDH, a type of enzyme. Either a renal ultrasound or a high-resolution abdominal CT angiography can aid in diagnosis.
If the emboli might have affected the heart valves, an echocardiogram should be performed. This type of specialist ultrasound uses sound waves to create pictures of the heart’s chambers, valves, walls and the blood vessels.
The diagnosis can also be made clinically when the disease shows up rapidly, usually within a few days after a procedure involving the blood vessels, and is often accompanied by symptoms like blue toes or a skin discoloration condition known as livedo reticularis.
Treatment Options for Cholesterol Emboli
The right treatment for cholesterol emboli, or clots, can vary greatly depending on the specifics of a patient’s situation. For example, the organ affected, how long symptoms have been present, and the type of clot will all influence the best course of action. In acute scenarios, the immediate treatment is typically mostly supportive. It can also be necessary to stop anticoagulation (blood thinning) treatment if it’s believed to be making the problem worse.
Long-term treatment usually requires identifying the source of the clots and taking preventative measures against further spread. For example, if clots formed in the heart, prescriptions may be given for blood thinning medication. For patients with larger arteries affected by atherosclerosis (hardening), medications that prevent blood vessel blockage and cholesterol-lowering drugs could be recommended. As it’s known that cardiovascular procedures can cause more clots to form, they should be avoided if possible.
Patients with chronic kidney disease, a common serious complication, could benefit from a dedicated approach to treating high blood pressure and regularly checking kidney health. Studies have shown that treatments to remove ‘bad cholesterol’ from the blood – LDL apheresis – combined with anti-inflammatory steroids, restored better kidney function than steroids alone in patients with cholesterol clots.
If a patient is suspected to have inflammation of blood vessels (vasculitis), they can be treated with high-dose steroids and anti-inflammatory therapy. However, while steroids can have benefits; they also carry risks such as increasing the chances of infection, messing with metabolism and nutrition, and hindering wound healing. Therefore, it’s necessary to balance these risks against the benefits when deciding on a treatment plan.
What else can Cholesterol Emboli be?
When diagnosing cholesterol emboli, doctors must consider a few other conditions which can also lead to blockages in the small blood vessels of various organs, causing inflammation. These may include:
- Different types of blood vessel inflammation, such as Takayasu disease, polyarteritis nodosa, or Henoch-Schonlein purpura.
- Antiphospholipid syndrome, a disorder that leads to abnormal blood clotting.
- Infective endocarditis, an infection of the heart’s inner lining.
- Blood disorders like thrombotic thrombocytopenic purpura or disseminated intravascular coagulation.
- Cryoglobulinemia, a condition that affects the blood’s proteins.
- Left atrial myxoma, a rare, noncancerous tumor on the heart.
Other serious conditions that may have similar symptoms to cholesterol emboli include certain cancers like lymphoma, diseases such as polycythemia vera or tuberculosis, and conditions affecting blood vessels or kidneys.
For example, Raynaud phenomenon (where small blood vessels narrow in response to cold or stress), pheochromocytoma (a rare tumor on the adrenal glands), or radiocontrast nephropathy (kidney damage caused by dyes used in some imaging tests) may also be considered.
Finally, doctors may also need to rule out conditions that can cause rapid kidney damage, like certain types of inflammation and scarring of the kidneys, or hypertensive nephrosclerosis, which is damage caused by high blood pressure.
What to expect with Cholesterol Emboli
People diagnosed with cholesterol embolization syndrome generally have an unfavorable prognosis because of related heart conditions. Survival rates after a diagnosis are 87% after one year, 75% after two years, and fall to just 52% after four years. Research indicates that the mortality rate can range from 63% to 81%.
Possible Complications When Diagnosed with Cholesterol Emboli
Cholesterol embolization syndrome can potentially lead to various serious complications. The type of complication you experience depends on the source of the embolus (a blockage-causing substance) and which organ it affects. Here are some potential complications:
- High blood pressure (Hypertension)
- Lack of blood flow to the intestine (Bowel ischemia)
- Kidney problems (Renal insufficiency)
- Stroke
- Final stage kidney disease (End-stage renal disease)
- Inflammation of the pancreas (Pancreatitis)
- Inflammation of the gallbladder (Cholecystitis)
- Loss of blood supply to the spleen (Splenic infarction)
- Narrowing of the carotid artery (Carotid stenosis)
- Loss of vision (Blindness)
- Skin rashes
- Insufficient blood supply to the heart (Myocardial ischemia)
- Multiple organs stop working at once (Multiorgan failure)
- Death
Preventing Cholesterol Emboli
To prevent cholesterol emboli, which are clumps of fat and cholesterol that can block blood vessels, patients should focus on reducing their risk factors. This includes adopting a healthy diet and regular physical activity to assist with maintaining a healthy weight and keeping blood pressure under control. Quitting smoking is also strongly advised. Patients should understand the importance of taking medications as directed and attending scheduled appointments with their doctors.
In some cases, if a definite source of the emboli can be determined and the patient is suitable for surgery, a surgical or endovascular treatment might be recommended. At this point, patients should take the time to understand the potential risks and benefits of the treatment. They should be fully informed about the expected outcomes, code status, meaning their current health statuses, and should discuss advance directives, which are orders voicing their medical treatment preferences in the event they are unable to communicate or make decisions.