What is infective endocarditis?
Infective endocarditis (IE) [also called bacterial endocarditis (BE), or subacute bacterial endocarditis (SBE) ] occurs when germs (especially bacteria) enter the blood stream and attack the lining of the heart valves. Infective endocarditis causes growths or holes on the valve or scarring of the valve tissue, most often resulting in a leaky heart valve. Without treatment, endocarditis is a fatal disease.
Bacteria get into the bloodstream regularly when eating, during teeth brushing and when passing stools. Normal heart valves are very resistant to infection, but diseased valves have defects on the surface where bacteria may attach. The bacteria rapidly form colonies, grow vegetations and produce enzymes, destroying the surrounding tissue and opening the path for invasion. Dental procedures (particularly tooth extractions) and endoscopic examinations are associated with bacteria in the blood, so prophylactic (preventative) antibiotics are advised for patients with valve disease. Intravenous drug abusers are at high risk for developing IE. Click here to learn more about endocarditis
In many cases of endocarditis, antibiotics alone can cure the infection. However, in about 25-30 percent of patients with IE, surgery is needed during the early acute phase of infection due to severe valve leakage or failure to control the infection with antibiotics. Another 20-40 percent of patients will require surgery later. Patients who have had prior valve replacement, and have an infected prosthetic valve (prosthetic valve endocarditis or PVE), are more likely to need surgery than those with their original valves (native valve endocarditis).
The timing of surgery, the type of surgery, and the antibiotics used to treat the endocarditis are based on several issues:
- The diagnosis of IE
- The microorganisms involved and their presence in the blood or tissues of the valve
- The location of the IE and the extent of heart and valve damage
- Presence of complications, such as heart failure, sepsis, emboli (blood clots or stroke), and other organ involvement
- History of previous IE
Evaluation of infective endocarditis includes:
- Evaluation of symptoms
- Blood cultures - blood tests for microorganisms
Patients who require surgery more urgently include those with:
- Moderate to severe or progressive heart failure due to valve regurgitation (leaky heart valve), caused by the infection
- Vegetation or blood clots blocking the valve
- Abscesses or aneurysm around the aortic valve. This occurs more often with IE of the aortic valve and PVE, and can be difficult to diagnosis.
- Emboli (blood clots or stroke), that continue to occur, even after antibiotic therapy. Some patients have large attached, but mobile vegetations (growths), likely to break loose from the valve.
- Certain fungal infections with extensive valve damage
- An unstable prosthetic valve
Other patients who may require surgical treatment for IE include patients with:
- Infective endocarditis, persistent fever, and other signs of uncontrolled infection, even after adequate antibiotic therapy has been given
- An infection on a new prosthetic valve, supported by positive blood cultures and an echocardiogram showing vegetation on the valve
- Certain types of difficult to treat bacteria such as non-candida fungal endocarditis or pseudomonas infection
- Very large vegetations, or growths on the valve leaflets and risk of embolism
These patients should be evaluated by the surgeon. After the surgeon reviews the particular risk factors and extent of infection, an individualized decision is made on how and when to proceed with surgery.
Along with the type of microorganism, complications related to IE, and the extent of valve damage, the surgeon also looks at other factors when determining if and when to have surgery and the risks involved. These include transient ischemic events or stroke, the age of the patient, and intravenous drug abuse.
Surgery for Infective Endocarditis (IE)
Surgical treatment of infective endocarditis is aimed at:
- Removal of all infected tissue
- Drainage of abscesses (collection of pus)
- Repair of the heart tissue
- Repair or replacement of the affected valve
Surgery for endocarditis is very specialized and demanding. It requires extensive experience and familiarity with different reconstructive methods including the use of homografts (human cadaver valves). Transesophageal echocardiograms (TEE) performed before, during and after surgery help to guide the surgeon and ensure valve function is optimal.
Debridement - removal of infected tissue. If the infection has affected only the valve leaflets (cusps), removal of the infected matter will be sufficient. However, if the infection has affected more of the valve or into the heart tissue, then debridement will require a more technically difficult approach. Photo(s) of IE and valve debridement (please note: very graphic)
Valve reconstruction - depending on the specific surgical case, the surgeon will repair the valve or replace the valve with a new valve (valve prosthesis). The prosthesis may be biological, mechanical or a homograft. The homograft has proven to be particularly effective in cases with severe aortic valve endocarditis. In some cases of aortic valve IE, the Ross Procedure may be used. Photo(s) of IE and valve reconstruction (please note: very graphic)
Care after surgery
After surgery, patients with IE always require a complete six-week course of antibiotic therapy. The type of and duration of therapy will vary depending on the results of blood tests (cultures), severity of infection, and possible other sources of infection.
Patients with IE have a greater chance of developing IE again and should take precautions to prevent future episodes. Fungal infections may require life-long treatment to prevent recurrence. Click here to learn more about IE prevention
The recovery after heart surgery, is similar to other patients after heart valve surgery. However, the recovery may be slower, depending on the extent of illness prior to surgery.
Olaison L, Pettersson G. Current best practices and guidelines. Indications for surgical intervention in infective endocarditis. Cardiology Clinics 2003: 21: 235 - 251.
Pettersson G, Carbon C. Recommendations for the surgical treatment of endocarditis. Clinical Microbiology Infection 1998: 4: 3S34-3S46.
Click here to find related publications written by Heart and Vascular Institute physicians
*a new browser window will open with this link. The inclusion of links to other web sites does not imply any endorsement of the material on the web sites or any association with their operators