Overview of Endomyocardial Biopsy
The usefulness of a medical procedure called endomyocardial biopsy (EMB), which is used to study heart diseases, is still a subject of debate. Also, how frequently it’s used can vary greatly among different medical facilities. Essentially, EMB is a way to help diagnose various heart conditions when non-invasive tests, or ones that don’t involve entering the body, can’t provide a clear answer.
However, performing EMB is not without risks, and there are other tests that are less invasive – like heart MRI scans or PET scans – that are sometimes more appropriate. That being said, there are situations where EMB can be very helpful in providing a diagnosis when no other test can. All diagnostic procedures, including EMB, have varying degrees of accuracy and precision in detecting different diseases.
The EMB procedure involves several stages: deciding if the procedure is necessary, taking the biopsy, handling the sample, and then interpreting the results. Although its primary use is for clinical diagnosis, EMB is also utilized for research purposes.
Anatomy and Physiology of Endomyocardial Biopsy
Endomyocardial biopsy (EMB) is a medical procedure that can be performed on either side of the heart’s ventricles, which are the two lower chambers of the heart that pump blood out to the body. The most common place where doctors often sample tissue for this procedure is the septum of the right ventricle. This is like a wall that separates the two ventricles. To access the right ventricle, doctors usually use the right or left femoral vein, located in your thigh, or the right internal jugular vein in your neck. However, in the United States the neck vein is the usual choice. For the left ventricle, doctors will access it through the right or left artery in your thigh, or through the right artery in your wrist.
When performing an endomyocardial biopsy, it’s extremely beneficial for the doctor to fully understand the structures of your heart and where certain diseases like to make themselves at home. This not only ensures a better result for the biopsy but also helps to keep you safe and to prevent potential complications. For instance, arrhythmogenic right ventricular dysplasia, a heart condition that produces abnormal heart rhythms, tends to impact the “free wall” of the right ventricle, which is an area that is at high risk for damage during a biopsy. Meanwhile, tumors can often be found in very specific areas of the heart. Myxomas, a particular type of tumor, are usually located within the left atrium or the upper left chamber of the heart. Therefore, knowing where exactly to take samples is crucial.
In order to increase the accuracy of the results for certain conditions that could affect widespread areas of the heart, more samples might have to be taken. The use of detailed heart imaging tools such as a cardiovascular MRI along with an EKG, which measures the electrical signals of your heart, can help guide your doctor to gather samples from the areas most affected by conditions like myocarditis (inflammation of the heart muscle) or cardiac sarcoidosis (an inflammatory disease that could affect the heart). This way, doctors have a better chance at identifying and treating the issues impacting your heart’s health.
Why do People Need Endomyocardial Biopsy
Endomyocardial biopsy (EMB) isn’t often used to diagnose heart disease. It’s a test that isn’t used often and doesn’t have many solid studies to support its use in any specific heart condition. The recommendations for this test’s use mostly come from looking back at past patient data, individual case studies, and expert opinion.
This test is most useful for diagnosing certain heart conditions. These conditions include heart failure of unknown of cause, cardiac sarcoidosis, amyloidosis, inflammatory heart muscle diseases, storage diseases (like hemochromatosis), cardiac masses, and side effects from chemotherapy. EMB can also be useful for monitoring patients who have had a heart transplant or differentiating between specific heart conditions.
For instance, EMB is helpful for heart failure patients where other causes have been ruled out. These patients can potentially suffer from conditions called Fulminant lymphocytic myocarditis (FLM), giant cell myocarditis (GCM), and necrotizing eosinophilic myocarditis (NEM). FLM patients often recover on their own, while GCM and NEM patients often need treatments to suppress the immune system and may require support from a mechanical heart device.
The test can also assist in diagnosing cardiac sarcoidosis, although it can be difficult to differentiate from other similar conditions. Patients with cardiac sarcoidosis usually respond well to steroid treatments and can be treated for irregular heartbeats with an implantable device.
Furthermore, EMB can identify hypersensitivity myocarditis (HSM), a rare disorder that often presents as a type of progressive heart muscle disease. Recognizing and treating this disorder as well as Eosinophilic cardiomyopathy (ECM), a related condition, is crucial because removing the allergic cause or treating the underlying parasite infection may also treat the heart condition.
In patients treated with chemotherapeutic agents like anthracycline, EMB can be used if the cause of heart dysfunction is in question. It’s also useful in diagnosing restrictive cardiomyopathy (RCM), a disease that can be caused by accumulation of abnormal substances in the heart tissue, or heart tumors. For certain heart conditions like arrhythmogenic right ventricular cardiomyopathy (ARVC), non-invasive tests are often used first, with EMB reserved for cases of diagnostic uncertainty.
Finally, EMB is crucial for patients who have had a heart transplant, as routine checks are necessary within the first year of transplant to detect any signs of the body rejecting the new heart and adjust treatments accordingly.
When a Person Should Avoid Endomyocardial Biopsy
Endomyocardial biopsy, or EMB, is a procedure that looks at the heart’s muscle. As it’s quite an invasive procedure, there are certain situations or conditions where it cannot, or should not, be performed. These are commonly referred to as contraindications. In some cases, these contraindications are absolute, meaning under no circumstances should the procedure be performed.
For example, if a patient has certain heart valve conditions like vegetations or stenosis (a narrowing of the heart valves), or blood vessel issues such as aneurysm (a bulging in a blood vessel) or thrombosis (blood clots), these are absolute reasons not to proceed. Another important absolute contraindication is the presence of atrial myxomas, a type of noncancerous heart tumor. Since they can break off and block blood vessels, they should not typically be biopsied.
There are also relative contraindications; these are conditions where EMB might still be performed but with caution. This might be the case for those with a blood clotting disorder (coagulopathy), or individuals taking dual antiplatelet therapy (medicines to stop blood clots) or therapeutic anticoagulants (blood thinners).
If any of these contraindications exist, alternatives to a biopsy would need to be explored. These could include different types of heart imaging, such as tissue doppler echocardiography, which uses sound waves to create pictures of the heart; scintigraphy, a test that uses radioactive material to create images; or cardiac magnetic resonance imaging (CMRI), an imaging test that uses powerful magnets and radio waves to create pictures of the heart.
Equipment used for Endomyocardial Biopsy
A bioptome is a special tool used by doctors to take a small sample from your heart, known as a cardiac biopsy. This procedure is usually seen using a fluoroscopy, which is a type of live X-ray, or through an ultrasound of your heart known as echocardiography. Modern bioptomes have been improved to be more flexible and thinner than the earlier models.
The entrance to reach your heart for taking the biopsy can be made either through a vein or an artery, depending on whether the biopsy from the right or left part of heart is being taken. The doctors usually use the vein in your neck (internal jugular) or in your leg (femoral vein). For taking a biopsy from the left side of your heart, the doctor might make a small hole in the artery of your arm (radial artery) or in your leg (femoral artery).
The bioptome is gently moved forward into your heart through a small tube, also called a sheath, which has been inserted using a technique known as the Seldinger method. This technique is commonly used by doctors to access blood vessels without causing much damage.
Who is needed to perform Endomyocardial Biopsy?
A heart specialist, known as an interventional cardiologist with specific experience in performing heart muscle biopsies, is needed to lower the chance of any problems during the procedure. This procedure should preferably be done with the help of a highly skilled medical team, which includes nurses and technologists, in a heart examination laboratory, usually called a cardiac catheterization lab. This procedure involves the collection and examination of small samples of heart tissue.
Examining the heart tissue samples needs special knowledge and experience. There are other doctors, known as cardiac pathologists, who are trained specifically to look at these samples. They examine these samples taken from the heart muscle biopsy or from an autopsy (examination of a body after death). These doctors’ role is very crucial as the result of these examinations can often help determine the most appropriate treatment for the patient.
Preparing for Endomyocardial Biopsy
Doctors often use a tool called a bioptome to collect small samples of heart tissue in a procedure known as a heart biopsy. Different techniques can be used to guide this tool. One method is by using equipment that produces images through X-rays, called fluoroscopy, in a specially equipped room known as a catheterization laboratory. Alternatively, doctors can use ultrasound techniques at the patient’s bedside, either from within the heart or through the chest wall.
Using ultrasound methods to guide the bioptome is just as effective as using X-rays, and doesn’t make the procedure more complex or take longer. Another benefit is that ultrasound can be done without needing to expose the patient to any radiation.
Also, doctors can use more advanced techniques to make sure that the bioptome is targeting the right areas. These techniques use electrical maps of the heart or special imaging techniques like cardiovascular magnetic resonance (CMR), which can identify specific areas such as heart scars. Having this extra information can increase the chances of a successful biopsy.
How is Endomyocardial Biopsy performed
To prepare for an endomyocardial biopsy, a procedure where samples of heart tissue are taken to diagnose various heart conditions, the patient must stop taking any blood-thinning medication 16 hours before the procedure and for 12 hours afterward. Also, the patient’s blood-clotting test result, known as the INR, must be less than 1.5 before the procedure.
Once the patient is sedated and placed in a comfortable, lying down position, we will monitor their heartbeat, blood pressure, and oxygen levels. It’s important that we ensure their comfort during the procedure by using pain relief and sedation, which generally takes a few minutes. In order to accurately assess the heart’s condition, multiple small tissue samples will be taken.
These heart tissue samples will then be preserved in various solutions and examined under microscopes to identify any abnormalities. The samples will be stained with different chemicals to highlight specific features, helping us identify any heart problems like inflammation, abnormal cell growth, damage to heart muscle cells, scar tissue, unwanted fatty tissue, iron buildup, or abnormal protein deposits.
We measure the level of inflammation by counting specific immune cells and looking at immune response markers. We’ll also check for viral presence in the heart tissue, which might be causing heart problems.
For patients who had a heart transplant, we use a certain grading system to assess the tissue samples for signs of inflammation and heart muscle damage which is crucial for detecting organ rejection. You’ll also hear the term ‘Quilty lesions,’ which are specific changes in heart tissue commonly seen after a heart transplant.
It’s important to note that the endomyocardial biopsy procedure itself can lead to some changes or artifacts in the heart tissue samples that don’t really reflect any disease or condition. These include changes in muscle contraction, cell swelling, and changes in cell membranes, among others.
Possible Complications of Endomyocardial Biopsy
If you’re undergoing a procedure that involves taking a small tissue sample from your heart, known as an Endomyocardial Biopsy (EMB), there are some complications you should be aware of. These complications are generally divided into two types: acute (happening immediately after the procedure) and chronic (occurring over time).
Often dreaded acute complications could involve a collapsed lung (pneumothorax), irregular heart rhythms (arrhythmias), a hole in an organ (perfusion), fluid around the heart (pericardial effusion), pressure on the heart due to fluid build-up (pericardial tamponade), abnormal connections between arteries and veins (fistulas), blockage of the heart’s electrical signal (heart block), accidental puncture of an artery, blockage in the lungs’ blood vessels (pulmonary embolization), nerve damage, blood clots underneath the skin (hematoma), connections between an artery and a vein (arteriovenous fistula), blood clot in the deep veins (deep vein thrombosis), and damage to the valve in the heart that prevents blood from flowing back into the right atrium (tricuspid valve injury).
Patients who undergo multiple EMB procedures, particularly for monitoring a heart transplant, can experience tricuspid valve damage. Most of this damage is tolerable and won’t usually need valve replacement. However, doctors are careful to minimize sampling tricuspid valve tissue in patients who need many EMB procedures. Fortunately, severe issues occur in less than 1% of procedures, and minor ones happen in up to 6%.
In terms of chronic complications, these could include bleeding at the place where a doctor accessed a vein or artery, damage to the tricuspid valve, pressure build-up around the heart (pericardial tamponade), and blood clot in the deep veins.
The risks of EMB could depend on your health condition, the experience of your doctor, and the quality and knowledge at the medical center. It’s advised to seriously consider transferring to a medical center with EMB and heart pathology expertise if one is not available. Furthermore, patients with heart-related shock or unstable heart rhythms may need a heart failure specialist who can provide solutions, including heart support devices and possibly heart transplant procedures.
What Else Should I Know About Endomyocardial Biopsy?
Endomyocardial biopsy (EMB) is a medical procedure used to take a small sample of heart tissue for examination under a microscope. It’s important in diagnosing various heart diseases and informs doctors about the best treatment methods.
The EMB’s usefulness depends largely on how clear its results are for diagnosing a disease and how much it affects the choice of treatment. While it’s essential in uncovering the different diseases causing heart failure, sometimes, the diagnostic value of EMB might have limited impact on treatment decisions.
To accurately interpret tissue changes, it’s important to remember that what’s seen under the microscope doesn’t always directly relate to the symptoms a patient feels.
For some conditions, doctors might need to use more advanced techniques alongside EMB, such as electron microscopy and immunohistochemistry, which involve chemical staining and molecular analysis. Simple EMB examination may not be enough to diagnose diseases like hemochromatosis (a condition related to iron overload) and some storage diseases that widely affect the heart.
EMB’s role in diagnosing diseases continues to evolve. There’s ongoing debate about its use for diagnosing myocarditis (an inflammation of the heart muscle) as some patients who don’t meet the traditional criteria still end up being diagnosed with it. EMB isn’t always accurate for certain conditions like myocarditis and cardiac sarcoidosis (an inflammatory disease that could affect the heart); it only detects these conditions 25%-35% of the time.
Although it may not be very sensitive for all conditions, EMB is good at confirming specific diseases when doctors already strongly suspect them. In cases where initial suspicion of a disease is low, other tests may be a better choice. Scintigraphy, for instance, is a medical imaging test that can help rule out other diseases.
Combining EMB with other tools such as Cardiac MRI (CMR, a type of heart scan) can be more effective in diagnosing conditions like myocarditis.
