What is Tricuspid Valve Endocarditis?

Tricuspid valve infective endocarditis (TVIE) is a rare type of heart infection that mostly affects the tricuspid valve on the right side of the heart, which is less common compared to infections on the left side of the heart. It accounts for around 5 to 10% of all cases of heart infections overall. The tricuspid valve, which can be involved in up to 90% of these cases, is particularly impacted in people who use injectable drugs (IVDU). With the rise of injectable drug use in the United States since 2006, the occurrence of TVIE has also significantly increased.

Other risk factors can include having devices like dialysis catheters, pacemakers, or defibrillator leads. The most common bacteria causing TVIE is Staphylococcus aureus, but other bacteria from skin, and different types of Staphylococcus and Streptococcus bacteria can also cause this infection. For diagnosis, doctors use something called Duke’s Criteria. However, TVIE can be hard to detect as it can often present without the usual findings such as the presence of an abnormal heart sound (murmur), an associated lung infection or other visible symptoms like splinter hemorrhages, which are tiny lines seen under the nails.

Nevertheless, if discovered and treated early enough, TVIE can have a good outcome. Even though the occurrence of TVIE and right-sided heart infections are on the rise, antibiotics and potential surgical treatments remain the main, successful treatment methods.

What Causes Tricuspid Valve Endocarditis?

There are several key factors that can increase the risk of developing an infection in the tricuspid valve, a part of your heart. This condition is known as tricuspid valve infective endocarditis (TVIE). Here are some common risk factors:

People who use drugs intravenously (injected through the veins) make up about 30% to 40% of all TVIE cases. This type of drug use can lead to infections that affect the heart valves.

Having a Cardiac Implantable Electronic Device (CIED) can also increase the risk of TVIE. CIED includes things like pacemakers or defibrillators. If there’s an infection related to these devices, it may cause symptoms such as valve thickening and heart valve leaks, especially if blood tests also show that there are infectious agents in the blood.

Lastly, people who have a long-term central venous access, that allows medications or nutrients to be delivered directly into a large vein, can also have a higher risk for TVIE. This includes people undergoing hemodialysis (a treatment for kidney failure), parenteral nutrition (receiving nutrients through a vein), and chemotherapy.

Risk Factors and Frequency for Tricuspid Valve Endocarditis

There is a noticeable rise in the number of cases of right-sided infective endocarditis (RSIE) and tricuspid valve infective endocarditis (TVIE). In fact, one study found a 12-percent increase in hospital admissions due to infective endocarditis related to intravenous drug use (IVDU). It has been observed that IVDU is responsible for about 86% of all TVIE instances. Although TVIE is more commonly found in males, this ratio is gradually stabilizing. Over the years, the average age of those affected by TVIE has decreased and there is an increase in cases among the white population.

Signs and Symptoms of Tricuspid Valve Endocarditis

To diagnose Tricuspid Valve Infective Endocarditis (TVIE), doctors usually rely on a patient’s medical history and physical examinations. It can sometimes be tricky to identify this disease since it might develop slowly over time or not show the typical signs connected with Infective Endocarditis (IE). Observable symptoms like splinter hemorrhages or a heart murmur are not always present in TVIE patients. Nonetheless, there could be a variety of complications from this disease that present as different embolic phenomena. If a person experiences the following signs and symptoms, doctors must consider the possibility of TVIE:

Fever
Chills
Loss of appetite
Weight loss
Fatigue
Feeling of discomfort or illness (malaise)
Joint ache (arthralgia)
Shortness of breath during exertion (dyspnea on exertion)
A cough
Chest pain that worsens when you breathe in (pleuritic pain)
Abdominal pain

During a physical examination, the doctor might notice the following:

Rapid breathing (tachypnea)
Low blood pressure (hypotension)
Heart murmur
Enlarged spleen (splenomegaly)
Splinter hemorrhages (narrow, red to reddish-brown lines of blood under the nails)
Small red or purple spots on the skin (petechiae)
Red, painless spots on the palms and soles (Janeway lesions)
Purple or blue lumps on the fingers or toes (Osler nodes)
Blotchy retina with pale, round spots surrounded by hemorrhage (Roth spots)
Localized impaired or lost sense of function (focal neurologic deficits)
Swollen joints with accumulated fluid (joint effusion)
Rounded and widened fingers and toes (clubbing)

Testing for Tricuspid Valve Endocarditis

The diagnosis of tricuspid valve infective endocarditis (TVIE), a type of heart valve infection, is typically based on a commonly-used system known as the modified Duke Criteria. This standardized approach helps doctors to categorize the likelihood of infective endocarditis as definite, possible, or rejected.

According to these criteria, a definite diagnosis of infective endocarditis can be made if two main clinical signs are present. Alternatively, a definite diagnosis can be made if there is one main sign paired with three minor signs, or if there are five minor signs.

Possible endocarditis can be confirmed by the presence of one main sign along with two minor signs, or with three minor signs alone. The main and minor signs are divided as follows:

Main Signs:

A positive blood culture which includes: two separate blood cultures with organisms known to cause infective endocarditis, or blood cultures that are collected 12 hours apart and have organisms consistent with endocarditis, or three or more blood cultures that have organisms which can contaminate the skin, or a single positive blood culture of a bacterium called Coxiella burnetti.
Evidence of the disease affecting the inner lining of the heart, like plant-like growths on heart valves (vegetations), an abscess, new heart valve leakage, or the breakdown of an artificial heart valve.

Minor Signs:

Fever of more than 38 degrees Celsius (100.4 degrees Fahrenheit)
Certain immune responses, including ‘Roth spots’ effects on the eyes, painful bumps under the skin (Osler nodes), and kidney inflammation (glomerulonephritis)
A pre-existing heart defect or the use of intravenous drugs
Vascular symptoms: infection-related clots, arterial blocks, red spots on the eyes, splinter-like marks under nails, smooth red spots (‘Janeway lesions’) on palms or soles, or fungus-related swellings in the aorta
Positive blood culture that does not meet the main criteria

Additional tests are often recommended to find other signs of infective endocarditis. These may include blood tests, which could reveal higher than normal white blood cell count, elevated levels of proteins called ESR and CRP, a common form of anemia, or urinary problems. An EKG, or heart tracing, may show abnormal electrical activity.

Other scans, such as a chest X-ray or CT scan of the abdomen, can look for signs of infection in other parts of the body, like the lungs or spleen. Blood cultures (tests to find bacteria in the blood) are essential for people suspected of having TVIE, with a minimum of three samples advised.

An echocardiogram, a scan of the heart, is another essential test. The initial test is usually a transthoracic echocardiogram (TTE). If the results from the TTE are negative, but doctors still suspect infective endocarditis, a further scan called a transesophageal echocardiogram may be done. This second scan can also give more detail about heart valve problems before any surgery takes place.

Treatment Options for Tricuspid Valve Endocarditis

For some people with Tricuspid Valve Infective Endocarditis (TVIE), a kind of heart valve infection, doctors could consider a shorter duration of antibiotic treatment. This could be an option when patients don’t show any signs of kidney failure, spread of infection to other parts of the body, or combined left-sided infection. However, short-duration treatments aren’t generally recommended if the infection involves the aortic or mitral valves, if the bacteria causing the infection are resistant to common antibiotics like methicillin (MRSA), or if the infection is unusually complicated.

When TVIE is suspected, initial treatment usually starts with broad-spectrum antibiotics that target a wide range of bacteria. Most commonly, doctors will make sure the antibiotics can fight staphylococcus and streptococcus bacteria, the usual culprits in such infections. Vancomycin is often the first choice of antibiotics to use.

Antibiotic treatment can then be adjusted based on results from blood cultures, which reveal the exact type of bacteria causing the infection. Usually, once they’ve identified the bacteria, doctors continue the antibiotic treatment for about six weeks from the time they get the first ‘negative’ blood culture (meaning no bacteria are found).

A shorter course of antibiotic treatment could be considered in very specific circumstances. This could be an option for patients who: have an infection only on the tricuspid valve, haven’t experienced any complications as a result of the infection, and if the bacteria causing the infection come from the HACEK group of bacteria.

For patients infected with bacteria that are sensitive to methicillin (MSSA), doctors usually switch from vancomycin to a more effective antibiotic like nafcillin, oxacillin, or cefazolin. If the infection is caused by MRSA bacteria, doctors usually stick with a six-week treatment course using vancomycin.

If the infection can’t be managed with medication alone, surgical treatment might be necessary. Some indicators that surgery could be required include: if the vegetations (clumps of bacteria and cells) on the tricuspid valve are larger than 2cm and there’s evidence of septic pulmonary emboli (a serious complication where clots infected with bacteria break off and travel to the lungs), if the bacteria persist in the bloodstream for over a week despite suitable antibiotic treatment, or if there’s severe regurgitation (backward flow of blood) through the tricuspid valve leading to right-sided heart failure.

Infective endocarditis is a complex condition that can be challenging to diagnose. It often presents with vague symptoms that may be similar to a range of other conditions, including autoimmune diseases, infections, and cancers. Think of it as a syndrome – a group of symptoms that often occur together and characterize a particular disease or abnormal condition. Doctors use a diagnostic tool known as the Duke Modified Criteria, which considers all potential signs of this disease process.

Other conditions doctors might need to rule out when considering a diagnosis of infective endocarditis include:

Systemic lupus erythematosus (an autoimmune disease)
Polymyalgia rheumatic (an inflammatory disorder)
Lyme Disease (an infectious disease caused by ticks)
Antiphospholipid syndrome (a disorder that causes blood clots)
Libman sacks endocarditis (a rare form of endocarditis)
Atrial myxoma (a benign tumor in the heart)
Rheumatic fever (an inflammatory disease)
Marantic endocarditis (a form of endocarditis associated with cancer)

What to expect with Tricuspid Valve Endocarditis

Patients with TVIE, a type of heart infection, tend to have a better outlook compared to those with other types of infection in the heart. According to research, the death rate is lower in these individuals. In one study that looked at native valve endocarditis (an infection of the heart’s valves), the overall death rate was found to be 6%.

The size of vegetation (clusters of bacteria) involved is a key factor in determining how severe the condition may become. Those with vegetations that are larger than 1cm usually have higher mortality rates. Also, those who have both TVIE and an infection on the left side of the heart generally have a worse outlook. This is because these cases have a higher chance of developing an abscess, which is a collection of pus.

Possible Complications When Diagnosed with Tricuspid Valve Endocarditis

Complications related to TVIE can vary. Here are some examples:

Abscesses around the heart’s valve ring (Peri-annular abscess)
Blockages in the lung’s blood vessels due to infection (Septic pulmonary emboli)
Abscess in the spleen (Splenic abscess)
An infection-caused blood vessel bulge (Mycotic aneurysm)
Heart failure, where the heart can’t pump blood efficiently

Preventing Tricuspid Valve Endocarditis

Patients should be informed about the possible risks that can lead to TVIE, a kind of infection in the heart. If they are admitted to the hospital, it’s crucial to explain to them the dangers associated with the misuse of intravenous drugs or “IV drug abuse”. Also, every available means should be used to help these patients avoid falling back into the habit of injecting drugs again. These resources encompass providing information about and access to local rehabilitation centers, educating them about their condition and treatments, and discussing drug therapy options.