Treatment of Infective Endocarditis
The main goals of treatment of infective endocarditis are to address complications caused by valvular infection and to eradicate microbial agents from the thrombus. Some of the consequences of infective endocarditis may require surgical treatment.
General measures for stabilizing the patient include:
- Oxygen – reduces the hypoxia, supporting the function of the heart. This can potentially reduce the damage that the heart may sustain as a result of hypoxia.
- Treatment of heart failure – involves the use of the right combination of medications (including angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, digoxin, beta blockers, diuretics, aldosterone antagonists, and inotropes) and, in some cases, the use of special devices that help the heart contract properly.
- Hemodialysis – this method is used for patients with renal failure, which can occur as a result of embolization of the renal arteries or due to septicemia.
After the blood cultures are made (usually 3 to 5 sets of blood cultures done within 60-90 minutes) and the microorganism that caused infective endocarditis is identified, an antibiotic therapy, tailored to the patient, can be started.
However, in case of acute infective endocarditis, waiting can result in serious complications, which is why empiric antibiotic therapy is chosen based on the physical examination and clinical history. This way the doctors can determine the most likely infecting organisms. For example, patients who have a history of intravenous drug abuse are often infected by Staphylococcus aureus. Patients with prosthetic valves often have methicillin-resistant Staphylococcus aureus or coagulase-negative staphylococci.
On the other hand patients with subacute infective endocarditis can safely wait until the sensitivity results are available, as this doesn’t increase the risks of complications.
Intravenous administration of antibiotics is a preferred method, since it allows creating more reliable therapeutic levels of antibiotics within the bloodstream.
About 15-25% of the patients with infective endocarditis require surgery.
Indications for surgical treatment include:
- Congestive heart failure that is resistant to standard medical therapy.
- Fungal infective endocarditis (except for the one caused by Histoplasma capsulatum) – since this type of infective endocarditis is very resistant to drug therapy.
- If sepsis persists after 72 hours of appropriate antibacterial therapy.
- Recurrent septic emboli (especially if 2 weeks have passed after the antibiotic treatment).
- Rupture of an aneurism in an aortic sinus.
- Damage to the electrical conduction system of the heart by a septal abscess.
- Intracardiac fistula and paravalvular abscess – in most cases require surgical treatment.
- Persistent hypermobile vegetations create a risk of embolization and should be treated surgically.
- Infective endocarditis caused by multiresistant microorganisms is also in the majority of cases an indication for surgery.
- Patients who developed infective endocarditis as a result of pacemaker installation. In some cases this condition can be treated using drugs alone. However, in the majority of cases this type endocarditis can only be treated if the whole system is removed. According to American Health Association 2010 Guidelines, infections of cardiovascular implantable electronic device (CIED) can be treated and managed only through complete removal of the infected CIED. After the removal of the device, using a temporary transvenous pacer is the best option. However, immediate implantation of a permanent pacemaker can also be achieved. Moreover, AHA 2010 guidelines recommend careful evaluation whether the patient still requires CIED. If blood cultures were positive before the removal of the device, it is recommended to wait at least 72 hours after receiving negative blood cultures before installing a new pacemaker.
Removal of CIED should be done in the following cases:
o Patients with valvular endocarditis or sepsis.
o Patients with abscess formation, skin adherence, or device erosion.
In about 15-25% of infective endocarditis is the result of invasive procedures that cause a significant bacteremia. However, administration of pre-procedure antibiotics is only indicated in 50% of the cases, therefore only 10% of the cases of infective endocarditis can be prevented using antibiotics.
On the other hand, maintaining a good oral hygiene is a more effective method of prophylaxis, since gingivitis is one of the most common causes of spontaneous bacteremias.
Moreover, any form of diet doesn’t affect the progress of infective endocarditis in any way. The only reason why a person should adopt a diet with a lowered amount of sodium chloride is if infective endocarditis has led to congestive heart failure
Next Chapter: Endocarditis: Complications and Prognosis