Prosthetic valve or TAVI endocarditis:
symptoms not to ignore and what to do

Article written and reviewed by Dr Luca Moretti

People with a prosthetic valve, whether surgically implanted or placed by a transcatheter procedure such as TAVI, belong to the groups at highest risk of infective endocarditis. This does not mean that every fever is a valve infection, but persistent fever or fever without a clear explanation should be assessed more carefully than it would be in a person without prosthetic cardiac material.
Prosthetic valve endocarditis may present with fever, chills, fatigue, loss of appetite, weight loss and shortness of breath, but symptoms can be nonspecific and, especially in older people or after TAVI, fever may also be absent.

A doctor should be contacted promptly if any of the following occur:

• persistent, recurrent or unexplained fever or low-grade fever;
• chills or night sweats;
• marked fatigue or sudden deterioration in general condition;
• new shortness of breath or reduced ability to perform usual exertion;
• leg swelling or other signs of heart failure;
• confusion, sudden weakness on one side of the body or other possible embolic signs;
• recurrence of fever after a recent infection, healthcare procedure or hospitalization.

Prosthetic valve endocarditis is more difficult to diagnose and treat than many forms involving native valves. The monograph on prosthetic valve endocarditis and the one on transcatheter valve endocarditis discuss microbiology, imaging and treatment in depth. Here the aim is to clarify what a person living with a prosthetic valve or TAVI should know in practical terms.

Why a prosthetic valve increases the risk of endocarditis

A prosthesis is foreign material that becomes integrated into the heart. If microorganisms enter the bloodstream, they can adhere to the prosthetic material or surrounding tissues and form a biofilm, a structure that partly protects bacteria from the immune system and antibiotics. For this reason, prosthetic infections can be more difficult to eradicate and have a greater risk of extending to the valve annulus and nearby tissues.
Prosthetic valve endocarditis may occur soon after surgery or after a longer interval. Early forms are more closely related to the healthcare environment and the procedure, whereas late forms may result from bacteremias acquired subsequently.

TAVI is also a prosthetic valve. ESC guidelines report an incidence of endocarditis after TAVI of approximately 0.3-1.9 cases per 100 patient-years, with a higher risk during the first year and especially in the first months. Overall, the risk is similar to that observed after surgical aortic valve replacement, but the patient profile is often different: people receiving TAVI are frequently older and have more comorbidities.
The risk does not, however, become zero once the first year has passed. A prosthetic valve remains a predisposing condition for life.

Which symptoms should not be ignored

The most common symptom remains fever, but it is not mandatory. In post-TAVI endocarditis, case series report that a non-negligible proportion of patients may present without obvious fever. For this reason, unexplained deterioration in general condition, weakness, loss of appetite, weight loss, chills or night sweats should also be considered.
The onset of dyspnea or a rapid decline in exercise tolerance may indicate that the prosthesis is not functioning properly or that the infection has caused heart failure. Leg swelling, difficulty breathing while lying flat or waking at night because of shortness of breath increase the urgency of assessment.

As in other forms of endocarditis, fragments of infected material can embolize. Sudden speech disturbance, weakness of an arm or leg, facial asymmetry, loss of vision or altered consciousness are possible signs of stroke and require an immediate call to 112 or 118.
The disease should not instead be sought by trying to recognize rare signs such as petechiae or skin lesions: they may occur, but their absence does not exclude endocarditis.

Why diagnosis is more difficult with prosthetic valves and TAVI

The diagnostic pathway begins with blood cultures and cardiac imaging. Blood cultures should be obtained before antibiotics when the clinical situation allows, because identifying the microorganism is essential for selecting treatment. Transthoracic echocardiography is normally performed first, but in prosthetic valves it may be limited by artifacts and acoustic shadowing.
For this reason, transesophageal echocardiography plays a central role when prosthetic valve endocarditis is suspected. It allows better visualization of vegetations, abscesses, pseudoaneurysms, fistulas and prosthetic valve dehiscence.

Even transesophageal echocardiography, however, may be inconclusive. In TAVI, the device's metal frame makes imaging particularly complex, and vegetations may be located on the frame or adjacent structures rather than only on the valve leaflets. For this reason, modern diagnostic strategies often integrate cardiac CT and 18F-FDG PET/CT, especially when echocardiography does not explain a strongly suspicious clinical picture.
CT is useful for defining the extent of disease and perivalvular complications; PET/CT can show abnormal inflammatory activity around prosthetic material. Combining these techniques is one of the most important developments in the contemporary diagnosis of prosthetic valve endocarditis.

How prosthetic valve endocarditis is treated and when surgery is needed

Antibiotic treatment is tailored to the microorganism and its susceptibility. In prosthetic valve endocarditis, treatment is generally longer than in native valve disease, and guidelines normally indicate at least 6 weeks. The patient is monitored with blood cultures, blood tests and imaging to verify that the infection is resolving and that the prosthesis continues to function adequately.
The presence of a prosthetic valve does not automatically mean that it must be replaced. Surgery is, however, particularly important when infection causes heart failure, severe prosthetic dysfunction, dehiscence, abscess, fistula or persistent fever and bacteremia despite appropriate treatment.

In surgically implanted prostheses that become infected early, especially when infection is extensive, an antibiotic-only strategy often has an insufficient likelihood of eradicating the problem and cardiac surgical assessment is essential. Decisions are made by considering age, frailty, extent of infection, microorganism and operative risk.
After TAVI, the choice may be even more complex because many patients have high surgical risk and evidence regarding the benefit of surgery is not uniform. Guidelines therefore indicate individualized assessment by the Endocarditis Team, with surgery reserved for patients in whom complications, anatomy and overall risk make the procedure reasonable.

What people with a prosthetic valve can actually do to reduce risk

Prevention does not mean taking antibiotics every time fever develops. It is more important to maintain good oral hygiene, promptly treat dental and skin infections, avoid nonsterile procedures and inform dentists and physicians about the presence of the prosthesis.
People with prosthetic valves, including transcatheter valves, are among the high-risk groups for whom antibiotic prophylaxis is recommended before certain invasive dental procedures. Prophylaxis does not apply to every dental visit and should be prescribed according to the type of procedure.

If persistent fever develops without a clear cause, especially with chills or malaise, it is preferable not to start antibiotics independently before assessment. In high-risk patients, it may be important to obtain blood cultures before treatment, because empirical therapy started at home can make it more difficult to identify the pathogen.
It is also useful to carry documentation relating to the prosthesis or TAVI and always report the type of procedure performed when attending an emergency department or another healthcare facility.

Frequently asked questions about endocarditis, prosthetic valves and TAVI

Does fever in someone with a prosthetic valve always mean endocarditis?
No. There are still many causes of fever. However, persistent, recurrent or unexplained fever warrants more rapid assessment because a prosthetic valve is an important risk factor.

Can endocarditis occur years after the operation?
Yes. The risk is higher during certain early periods, but a prosthetic valve remains a predisposing condition even years later.

Can a TAVI become infected like a surgical valve?
Yes. Endocarditis after TAVI is a form of prosthetic valve endocarditis and has an overall incidence similar to that observed after surgical aortic valve replacement.

Why are PET/CT or CT needed if an echocardiogram has already been performed?
Prosthetic material may limit echocardiographic visualization. CT and PET/CT can show anatomical complications or inflammatory activity that are not clear on echocardiography.

Is another operation always needed?
No. Surgery is indicated mainly in complicated forms. After TAVI in particular, the decision requires individualized assessment of benefit and risk.