What is Lambl Excrescences?
Lambl excrescences are rare growths that develop in the heart at the sites where the heart valves meet, known as valvular coaptation sites. They appear on an echocardiogram, which is a scan that looks at the heart and blood vessels, as thin, very mobile, thread-like strands. These thread-like strands can be discovered on an echocardiogram by chance or in connection with serious problems like an embolic stroke or acute coronary syndromes (heart conditions that cause sudden, reduced blood flow to the heart) if they break off and travel to other organs.
Lambl excrescences are named after Vilem Dusan Lambl, a physician-scientist from Bohemia, who first identified these thread-like growths on an aortic valve (one of the four main valves in the heart) in 1856. The detailed examination of these structures took place around a hundred years later by F. Margarey.
Vilem Dusan Lambl is also known for his first detailed description of the parasite named after him, Giardia lamblia. This parasite was outlined by him in microscopic drawings. Lambl also made the initial description of what bladder cancer cells and spondylosis (a type of arthritis spurred by wear and tear to the spine) look like.
What Causes Lambl Excrescences?
Lambl excrescences are thin, thread-like structures that are neither attached at a base nor connected by a stem. They are typically found where the flaps inside our heart valves touch. When looked at closely, we can see that they are not made of living cells but are more like a skeleton made of sturdy, rubbery tissue covered by a layer of non-living material. They are further coated by a thin layer of cells. These structures do not have any blood vessels, which means they don’t undergo the usual healing process that involves new tissue growth. We commonly find Lambl excrescences on human heart valves, but they can also appear on artificial ones. On rare occasions, they can occur in other parts of the heart like the string-like tendons or the wall separating the two upper compartments of the heart.
Lambl excrescences can be a single thread or a group. They are about the width of a grain of sand and can stretch to the length of a sunflower seed. Their growth is limited because they exist in high-stress parts of the heart valves that are subjected to strong pressures, especially the aortic valve – the main outlet for our hearts. Sometimes, many excrescences can stick to each other, forming larger structures that can stretch up to the length of a jelly bean. Some reports suggest a link between these larger excrescences and strokes, but no strong scientific evidence proves that the size of these structures increases the risk of stroke.
Risk Factors and Frequency for Lambl Excrescences
Transesophageal echocardiogram (TEE), a heart test, is known to detect valvular strands in 5.5% of the general population. This percentage jumps to 40% in patients being investigated for unexplained strokes. Valvular strands, known as Lambl excrescences, can be found in both adults and children, but they are more frequently found in adults, with the number increasing with age.
Within the adult population, the highest prevalence of Lambl excrescences is found between the ages of 61 and 70. After this age range, detection decreases due to the increased calcification, or hardening, of aging heart valves, which can conceal the Lambl excrescences.
It’s also noteworthy that men are more likely to have Lambl excrescences than women. Additionally, although these growths can occur on all heart valves, native or artificial, they are most often found on the left side of the heart, specifically the aortic valve more so than the mitral valve. When Lambl excrescences don’t cause symptoms and are monitored over several years, they appear to remain stable without significant changes in shape or size.
Signs and Symptoms of Lambl Excrescences
Lambl excrescences are often silent and are usually found unexpectedly while conducting a heart scan or at an autopsy. In some instances, especially when they are located on the aortic valve flaps, these growths can break away and become lodged in organs located elsewhere in the body. This can cause strokes, heart attacks, or lung blockages. If these formations grow sufficiently large, they can obstruct the heart valves even without moving to other parts of the body. Depending on the organ impacted, the condition may manifest with a range of neurological and heart or lung symptoms.
Symptoms pointing to a stroke can include loss of muscle control, sensation loss, trouble with speech, difficulty swallowing, vision problems, facial muscle weakness, and loss of coordination. Heart and lung symptoms can include chest pain, shortness of breath, excessive sweating, fainting, dizziness, nausea, vomiting, low oxygen levels, low blood pressure, abnormal heart rhythms, changes in electrocardiogram (ECG – a test that measures your heart’s electrical activity), and high heart-specific protein levels.
- Loss of muscle control
- Sensation loss
- Trouble with speech
- Difficulty swallowing
- Vision problems
- Facial muscle weakness
- Loss of coordination
- Chest pain
- Shortness of breath
- Excessive sweating
- Fainting
- Dizziness
- Nausea
- Vomiting
- Low oxygen levels
- Low blood pressure
- Abnormal heart rhythms
- Changes in ECG readings
- High heart protein levels
Testing for Lambl Excrescences
The best tool for spotting and analyzing Lambl excrescences (tiny, thread-like growths on the heart valves) is a medical test called a transesophageal echocardiogram (TEE). This technique employs sound waves to take pictures of the heart, displaying the tiny growths and showing their attachments to the valves, their place in the heart, and how mobile they are. However, if a TEE can’t be done, a CT scan, which uses X-rays to create detailed pictures of the heart, will work just fine.
Despite how revealing these images can be, the surest way to diagnose Lambl excrescences is to analyze a sample of the growths under a microscope when it’s plausible.
On the images taken during the echocardiogram, Lambl excrescences appear as skinny, highly mobile, thread-like wisps on the heart valve’s line of closure. When the echocardiogram scans horizontally (or short-axis view), these growths look like lines sticking out from the ends of the aortic valve cusps, the flaps that open and close to let the blood flow in our hearts. When viewed from a vertical (or long-axis) perspective, these strands can be seen on all three flaps of the aortic valve.
Treatment Options for Lambl Excrescences
There are no agreed-upon guidelines for treating Lambl excrescences, which are rare, tiny wart-like growths on heart valves. The planned approach is always based on individual case reports.
Multiple treatments, including medication and surgery, have been used to manage Lambl excrescences. If a patient has no symptoms, it may be best to watch the condition closely with repeated heart scans or echocardiograms. If a stroke occurs alongside these growths, a detailed investigation should be done to find the causes of the stroke. This could involve an ultrasound of the neck arteries, a blood clot disorder test, and a complete heart scan examining all parts of the aorta, the main artery that carries blood from the heart to the rest of the body.
If the investigation doesn’t reveal any specific cause, patients can be treated with medications that thin the blood, such as aspirin or clopidogrel/dipyridamole, or anticoagulants like coumadin, which prevent the formation of new clots. For people who experience recurrent strokes linked to Lambl excrescences, surgically removing the growths could be an option.
The decision between surgery and maintaining the symptoms through medicine depends on the specifics of each case and the potential risks of surgery. We are yet to establish the effectiveness and benefits of these treatments in terms of reducing mortality.
Because there’s no consensus so far, it’s hard to rule out the chance of Lambl excrescences causing an embolic stroke — a stroke caused by a clot traveling to the brain. Medical providers should be mindful of this possibility and include it as a potential diagnosis in patients with strokes of unknown origin. A comprehensive heart scan should always be included in the evaluation of an embolic stroke when the source of the clot is unknown.
What else can Lambl Excrescences be?
Lambl excrescences, unusual growths on the heart valves, need to be differentiated from several other possible medical conditions. These may include:
- Fibroelastomas
- Valvular vegetations
- Myxomas
- Cardiac thrombi
- Nonbacterial vegetations
- Other cardiac tumors
- Metastases
All of these conditions pose different risks of material breaking off and blocking blood flow. Distinguishing Lambl excrescences from these similar conditions can be challenging.
Lambl excrescences look similar to fibroelastomas but differ in some key characteristics. Fibroelastomas are larger, softer, usually found in different locations in the heart, and have multiple layers of cells on the surface. Lambl excrescences, however, are smaller, positioned at the line of valve closure, and have only one cell layer on the surface. They are also less likely to grow due to their high-stress location, whereas fibroelastomas are usually in less stressed areas and as a result, are larger and thus more likely to cause blockages. Fibroelastomas also often require surgical removal.
Another condition to differentiate from Lambl excrescences is endocarditis-related valvular vegetations, which are irregular masses that appear different from other structures in the heart on imaging. These can stick to any part of a valve and are often accompanied by other signs of infection such as abscesses and valve splitting.
Nonbacterial vegetations, such as Libman Sacks thrombotic vegetations, can also appear anywhere on a valve. These are somewhat round, not connected by a stem, and do not move independently of the valve.
What to expect with Lambl Excrescences
The outlook for people who don’t show any symptoms but are found to have Lambl excrescences, which are small, threadlike growths, is generally very good. However, if these growths are associated with complications such as a stroke caused by blocked blood flow to the brain, a sudden, severe heart problem, or a potentially life-threatening clot in the lungs, the outlook is the same regardless of what caused these complications. In simpler words, no matter what specifically led to these issues, the outcomes are the same as if they’re caused by other things.
Possible Complications When Diagnosed with Lambl Excrescences
Most people with Lambl excrescences, a type of tissue overgrowth, don’t even realize they have it because they typically don’t display any symptoms. However, complications can occur when these overgrowths break off and move to distant parts of the body like the brain, heart, and lungs. They can cause problems such as strokes, heart blockages that can lead to heart-related problems, and blockages in the lungs if they’re large enough. Sometimes, these overgrowths can grow into much larger structures that can cause blockages in the heart valves, even without moving to other parts of the body.
Complications of Lambl Excrescences:
- Moving to distant organs like the brain, heart, and lungs
- Causing strokes due to lack of blood to the brain
- Causing acute heart problems due to blockages
- Causing blockages in the lungs
- Growing into large structures that can block heart valves
Preventing Lambl Excrescences
Lambl excrescences are unusual thread-like growths on the heart valves that are now detected more frequently, even on regular heart scans, thanks to improvements in ultrasound technology. These strands can be accidentally discovered or they may be associated with serious problems like stroke, heart embolism, lung embolism, or blockage of heart valves. However, it’s important to note that these growths do not directly cause these complications – they are simply found together.
When Lambl excrescences are detected, it’s very important to properly identify them and differentiate them from other similar conditions. If a patient experiences complications like a stroke caused by a clot, a detailed examination should be conducted to identify where the clot came from. Lambl excrescences should be considered as a possible cause, but only as a last option in unexplained strokes.
There are several treatment options that have been tried, including simple observation, medication to prevent clot formation, blood thinning medication, and surgery to remove the growths. However, at this time, there aren’t any specific guidelines backed by research to help doctors treat patients with these growths over the long term. Further research is urgently needed.
Due to the advancements in medical technology, the chances of spotting Lambl excrescences are increasing, which might lead to us seeing these unusual growths more often. Catching these growths early could help doctors manage patients better.
