What is Prosthetic Valve Endocarditis?
Prosthetic valve endocarditis (PVE) is a condition where an infection is present in parts of an artificially implanted or reconstructed natural heart valve. In simpler terms, it’s when the replaced or repaired valve of your heart gets infected. This condition makes up 20% of all endocarditis, an inflammation of the inside lining of the heart, and it’s the most serious form which comes with high risks and chances of death.
This disease is split into two types based on when it’s detected: early PVE and late PVE. Early PVE is found within the first year after the surgery, while late PVE is detected more than a year post-surgery. The reason why this distinction is crucial is because the types of microbes causing the disease are different depending on whether it’s early or late PVE.
What Causes Prosthetic Valve Endocarditis?
Early PVE, or Prosthetic Valve Endocarditis, can occur due to contamination during surgery or if it is spread to the valve through the bloodstream in the first few days or weeks after the operation. An abscess, which is a collection of pus, can form around the valve whether it is mechanical or biological. After about 2 months and up to about 12 months after the surgery, the infection can occur because of a late-onset hospital infection or an infection acquired outside the hospital.
In the first 2 months after surgery, the bacteria called Staphylococcus aureus is the most common cause of PVE. It is followed by other bacteria, like coagulase-negative staphylococci, gram-negative bacilli, and a fungus called Candida. Between 2 and 12 months after the surgery, the most common causes are bacteria like streptococcus, staphylococcus aureus, and coagulase-negative staphylococcus. These are followed by another type of bacteria called enterococcus. The most common type of coagulase-negative staphylococcus during this period is Staphylococcus epidermidis, mostly susceptible to the antibiotic methicillin.
Late PVE generally occurs due to an infection acquired outside the hospital; the types of germs involved are similar to those in native valve endocarditis, an infection that affects the heart’s original valves. The most common germs are streptococci and S. aureus, coagulase-negative staphylococci, and enterococci. Unfortunately, the death rate in late PVE is high in patients with multiple health issues who get endocarditis while in hospital for other reasons.
In both early and late PVE, there may be cases where the cultures do not show any germs, which is called culture-negative endocarditis. Other causes of PVE can be related to nontuberculosis mycobacteria (a particular type of bacteria called Mycobacterium chimera) and enterovirus.
Risk Factors and Frequency for Prosthetic Valve Endocarditis
Prosthetic valve endocarditis (PVE) accounts for around 20% of all endocarditis conditions and is found in up to 6% of individuals who have artificial heart valves. There are different rates of PVE when looking at the type of aortic valve replacement an individual had.
- The chance of getting PVE is 6 out of 1000 for people who received surgical aortic valve replacement (SAVR).
- People with bioprosthetic (made from human or animal tissue) SAVR are more likely to get PVE than those with mechanical SAVR.
- For those who received transcatheter aortic valve replacement (TAVR), the occurrence rate of PVE is similar to those with a bioprosthetic SAVR.
PVE is often associated with healthcare-acquired infections, particularly with later cases of PVE. These infections can be brought into the body during a hospital stay for other medical conditions, or during a visit to an external healthcare facility such as an infusion center, nursing home or during hemodialysis treatment.
Signs and Symptoms of Prosthetic Valve Endocarditis
Prosthetic valve endocarditis (PVE) is an infection that comes with symptoms much like other kinds of infectious endocarditis (IE). These symptoms include fever, chills, difficulty breathing, chest pains, loss of appetite, and weight loss. In addition to these symptoms, people might also feel generally unwell, have headaches, muscle pain, joint pain, night sweats, stomach aches, and a cough. It’s more common for people with PVE to have cardiac murmurs than with other types of IE. Splenomegaly (an enlarged spleen) and skin symptoms like petechiae (small red spots) or splinter hemorrhages (red to brown lines under the nails) are also common.
- Fever and chills
- Difficulty breathing
- Chest pains
- Loss of appetite
- Weight loss
- Feeling unwell
- Headaches
- Muscle pain
- Joint pain
- Night sweats
- Stomach aches
- Cough
- Heart murmurs
- Enlarged spleen
- Petechiae (small red spots)
- Splinter hemorrhages (red to brown lines under the nails)
Additionally, other less common symptoms may include Janeway lesions, which are painless red spots on the palms and soles, Osler nodes, which are violet-colored lumps mainly on the pads of the fingers and toes, and Roth spots, which are swollen, bleeding spots on the retina with white centers.
Testing for Prosthetic Valve Endocarditis
If your doctor thinks you might have an infection of an artificial heart valve, known as prosthetic valve endocarditis (PVE), there are several tests they might do. The first thing they tend to do is take three samples of your blood from different places in your body. This helps identify the bacteria causing the infection. This is especially true if you have a fever and a history of heart valve replacement.
After the blood tests, your doctor will likely order a type of ultrasound scan called a transthoracic echocardiogram, or TTE. This is a non-invasive test that uses sound waves to make pictures of your heart. It can help doctors find out what is wrong and plan further treatment.
However, if the TTE doesn’t give enough information, your doctor might recommend a second type of ultrasound called a transesophageal echo, or TEE. For this test, the ultrasound probe is guided down your throat into your esophagus — the tube that connects your mouth to your stomach — to get a closer look at your heart. This is typically done when the likelihood of having PVE is high, and the TTE scan proves to be non-conclusive. If the initial results from a TEE are not clear, doctors usually repeat it in a few days.
The TEE can detect abnormalities related to the infected heart valve, evaluate the valve’s functionality, investigate infection spread, help make decisions about possible surgery, and monitor PVE after treatment. The TEE tends to be more accurate than the TTE in diagnosing valve-related infections, particularly for PVE.
Other tests that your doctor may consider include a chest X-ray to check for lung infection, an electrocardiogram (ECG) to evaluate potential issues with your heart rhythm, and a CT (computerized tomography) scan. If the infection may have spread, your doctor might order a CT chest or abdomen to look for signs of this. If it is thought the infection might have spread to your brain, an MRI (Magnetic Resonance Imaging) test could be recommended.
If the ultrasound tests don’t give enough information, other advanced imaging techniques can be used such as a type of CT scan called a computed tomography angiogram (CTA), and a special type of PET/CT scan. These can be more effective than a TEE for identifying infections that have spread around the heart valve. The PET/CT scan involves injecting a small dose of a radioactive substance into the body, and can improve the accuracy of the diagnosis. It is also useful for monitoring the infection after finishing antibiotic treatment.
Treatment Options for Prosthetic Valve Endocarditis
In prosthetic valve endocarditis (PVE), a condition in which bacteria attach to, grow on, and damage the heart valve parts, the damaged areas, called “vegetations,” are often larger than in cases of native valve endocarditis (NVE) affecting the body’s own valves. The treatment for PVE requires a thorough approach, starting with identifying the specific bacteria causing the problem.
Once the bacteria are identified, an appropriate antibiotic treatment plan can be crafted to fight the infection. It’s important to ensure coverage against both gram-positive and gram-negative bacteria, two types of bacteria that cause infections. Specific antibiotics are then chosen based on the specific bacteria causing the infection.
If no specific bacteria are identified after taking blood cultures, initial treatment may include a combination of antibiotics. If PVE is caused by staphylococcus bacteria, the American Heart Association recommends a combination of antibiotics, depending on the strain of staphylococcus. Similarly, if PVE is caused by streptococcus or enterococcus, a combination of antibiotics will be required.
There are specific considerations for patients with allergies to certain antibiotics. For instance, if a patient has a non-severe allergy to penicillin, other antibiotics such as cephalosporin may be recommended. In more complex cases where the bacteria are resistant to traditional antibiotics, separate treatment plans may have to be developed, including the use of alternative antibiotics.
Early surgery may be necessary in certain PVE cases, especially when heart failure has developed, if there is persistent infection in the bloodstream despite antibiotic treatment, or if there are complications such as heart block or abscess. Surgery can also be a reasonable approach if the infection is caused by certain strains of bacteria or fungus that are highly resistant to antibiotics. After surgery, additional antibiotics are usually required to ensure any remaining infection is eliminated.
Treatment for PVE requires careful monitoring and a thoughtful approach. The goal is to choose the most effective treatment plan to eliminate the infection and ensure minimal damage to the heart.
What else can Prosthetic Valve Endocarditis be?
Prosthetic Valve Endocarditis (PVE) can be confused with other conditions because they share similar symptoms. These include:
- Native valve endocarditis: This is often seen in patients with symptoms that are similar to those of PVE.
- Atrial myxoma: This condition can cause symptoms like body-wide inflammation due to the release of immune response proteins, or may show signs of a disease that can affect the whole body due to blockages in blood vessels.
- Libman-Sacks endocarditis: Patients with this condition often have no symptoms and may have a medical history that suggests Systemic Lupus Erythematosus (SLE), an autoimmune disease.
- Nonbacterial thrombotic endocarditis (NBTE): This is a type of heart valve disease caused by clumps of cells and proteins that are not infected with bacteria. NBTE can result from certain cancers (like pancreas, lung, and colon), SLE, or tuberculosis.
- Rheumatic fever: This is diagnosed using the Jones criteria, which look for evidence of heart inflammation, arthritis, involuntary body movements, skin rash, under-the-skin bumps, and signs of a previous strep infection.
It’s necessary for doctors to consider all these conditions when making a diagnosis to ensure accurate and effective treatment.
What to expect with Prosthetic Valve Endocarditis
Despite doctors being able to correctly diagnose and undergo surgery for Prosthetic Valve Endocarditis (PVE), a condition where the artificial heart valve gets infected, the risk of serious illness and death remains high. This type of infection has the highest death rates when compared to other types of heart valve infections.
The most prominent signs pointing to a higher chance of death were continuous blood infection, heart failure, abscesses(areas filled with pus) in the heart and development of stroke. Continuous blood infection and infections obtained from healthcare settings are often linked with staphylococcus aureus bacteria causing heart valve infection. This type of bacteria often leads to high mortality in both PVE and native valve endocarditis, an infection of the heart’s original valves.
Infections obtained from healthcare settings related to PVE also point to a high chance of death while in the hospital. Other predictors for an increased mortality rate are large infected growths, patients who are not good surgical candidates, positive culture of infected heart valves, embolization (a blockage of blood vessels), and diabetes mellitus.
Possible Complications When Diagnosed with Prosthetic Valve Endocarditis
The most frequent heart-related issue associated with PVE, or prosthetic valve endocarditis, is heart failure. This may be caused by complications with the artificial valve or due to a heart attack triggered by clots or blockages. Other heart complications include abscess formation around the heart valve, abnormal connections within the heart, and inflammation of the heart lining.
Non-heart-related complications can arise from blockages in blood flow, the formation of abscesses in different parts of the body, or a type of bulging, infected blood vessel called a mycotic aneurysm. Neurological complications are also possible, including stroke, seizures, brain abscesses, a type of meningitis not caused by bacteria, sudden severe confusion, bleeding in the brain due to a ruptured mycotic aneurysm, or an inflammation of both the brain and meninges.
Kidney complications might include kidney damage due to clots, kidney abscesses, a type of kidney disease caused by the immune system response (glomerulonephritis) or inflammation of the kidney. All of these can cause acute kidney failure.
Complications in the lung may occur due to PVE affecting the right side of the heart; clots in the tricuspid or pulmonary valve can lead to a lung abscess, pneumonia, fluid in the chest cavity, or a collapsed lung. Other problems can include bone infections, infected joints, lasting bloodstream infections, or a specific type of bloodstream infection in fungal PVE. Despite appropriate treatment and surgery, death remains a serious concern following PVE.
Common Complications:
- Heart failure
- Heart-related abscesses
- Abnormal connections within the heart
- Inflammation of the heart lining
- Blockages in blood flow
- Formation of abscesses in the body
- Infected bulging blood vessels (mycotic aneurysms)
- Stroke
- Seizures
- Brain abscesses
- Meningitis not caused by bacteria
- Sudden severe confusion
- Bleeding in the brain due to ruptured mycotic aneurysm
- Inflammation of both the brain and meninges
- Kidney damage due to clots
- Kidney abscesses
- kidney disease caused by immune system response (glomerulonephritis)
- Inflammation of the kidneys
- Acute kidney failure
- Lung abscess
- Pneumonia
- Fluid in the chest cavity
- Collapsed lung
- Bone infections
- Infected joints
- Longstanding bloodstream infections
- Serious bloodstream infection in fungal PVE
- Potential death
Preventing Prosthetic Valve Endocarditis
Endocarditis is an ailment mainly caused by bacteria or fungi that targets the inside layer of the heart, including the heart’s valves. This means that the germs causing the sickness get into the heart through the bloodstream and begin attacking it. One form of endocarditis is called PVE and it affects replacement heart valves. The infection can injure these valves and stop them from working properly, which can lead to serious problems. Therefore, it’s crucial to get treatment as soon as possible to avoid any bad outcomes. People who have had heart valve surgery or those who inject drugs are more prone to get this type of infection.
If you or a patient show any of the following symptoms, you should go back to the emergency room immediately:
- Feeling tired for 2 to 3 days
- Struggling with physical activity more than usual
- Experiencing chest pain or difficulty in breathing
- Having a temperature over 100.4 degrees F (38.0 degrees C)
- Excessive sweating, especially at night
- Heart palpitations, which feels like your heart is beating irregularly
- Fainting
- Difficulty speaking
- Weakening of any limb or side of the face
- Noticeable spots on your fingernails, fingertips, the whites of your eyes, or other skin areas
- Signs of a stroke which include difficulties in speaking or the inability to move one side of your body
