Ch 18 Endocarditis Flashcards
What 6 sub-poplations have high prevalence of infective endocarditis?
Older age groups (>50)
Males
IV Drug Users
Advanced HIV infections
Hemodialyis AV shunts
Permanent pacemakers
What are the 3 high risk factors for endocarditis?
- Prosthetic valves
- Surgical shunts
- Previous Infective endocarditis
What are the 4 moderate risk factors for endocarditis?
- Congenital
- Acquired
- HOCM with LVOT obstruction
- Mitral Valve Prolapse with MR
What are the most common organisms to cause infective endocarditis of native heart valves?
- Streptococcus (Viridans and Bovis)
- Staphylococcus (aureus and epidermidis)
60-80%
What are the least common organisms to cause infective endocarditis of native heart valves?
Enterococci
Fungi
HACEK organisms
(Haemophilus species, Aggregatibacter species, Cardiobacterium hominis, Eikenella corrodens, and Kingella species)
What is the most common to least common valves that native endocarditis infects?
Left > Right
Aortic > Mitral > Tricuspid > Pulmonic
What are the 4 most common organisms that cause prosthetic valve endocarditis?
- Coagulase negative staphylococcus
- Staphylococcus Aureus
- Streptococcus
- Enterococci
What defines early vs. late prosthetic valve endocarditis?
Early = Within 2 months of valve implantation
Late = After 1 year of valve implantation
What % of prosthetic valve cases are infective endocarditis?
7-25%
What is the % of incidence of endocarditis of prosthetic valves in the 1st year?
3%
What is the % of incidence of endocarditis of prosthetic valves in each subsequent year after the 1st year?
1% each year
What % of patients with infective endocarditis are blood culture negative?
5-10%
What is the time frame of subacute bacterial endocarditis?
Weeks to Months
What is the time frame of acute bacterial endocarditis?
Fulminant <2 weeks
What is the virulence of subacute bacterial endocarditis?
Low grade pathogens, Mild clinical symptoms
Successfully treated with antibiotics
What is the virulence of Acute bacterial endocarditis?
Virulent organisms that lead to acutely ill patients
What % of infective endocarditis cases have serious complications such as heart failure, stroke and perivalvular extension?
Over 50%
What is the in hospital mortality rate of infective endocarditis?
15-20%
What is the 1 year mortality rate of infective endocarditis?
30-40%
What are the 4 major Duke Criteria?
Vegetation
Abscess
NEW partial dehiscence
NEW valvular regurgitation
What are the 3 minor Duke Criteria?
New nodular thickening
Valve perforation
Non-oscillating mass
What is the sensitivity of TTE for Endocarditis?
60%
What is the specificity of TTE for Endocarditis?
98%
What are the resolution limits of TTE?
> 3 mm
What is the sensitivity of TEE for Endocarditis?
100%
What is the specificity of TEE for Endocarditis?
100%
What is the sensitivity of TEE for Endocarditis on prosthetic valves?
94%
What is the specificity of TEE for Endocarditis on prosthetic valves?
100%
What is the negative predictive value of TTE and TEE negative for infective endocarditis?
95%
Doesn’t rule it out completely
Why is the NPV (95%) and not 100% for TTE and TEE in diagnosis of infective endocarditis?
Lesions that are < 2 mm (Not able to be seen by TEE)
OR
Vegetations have embolized
If you have a high suspicion of infectious endocarditis but have negative TEE, when should you repeat the study?
7-10 days
For AV valves, where is the vegetation usually?
Atrial side
For semilunar valves, where is the vegetation usually?
Ventricular side
For VSD endocarditis, where is the vegetation usually?
Orifice of RV, PV and TV
For infectious endocarditis causing AI, where is the endocarditis usually located?
AMVL
For infectious endocarditis causing MR, where is the endocarditis usually located?
Wall of the LA
MacCallum’s Patch
MacCallum’s patch is an irregular area of thickening in the posterior wall of the left atrium, usually due to previous severe acute rheumatic endocarditis

How do vegetations appear?
Irregular
Echo-dense
Independent
Mobile masses
What are endocarditits lesions composed of?
Platelets
Fibrin
Microbes
What are Liebman Sachs lesions?
Libman–Sacks endocarditis (LSE) is a form of non-bacterial endocarditis that is seen in association with systemic lupus erythematosus (SLE), antiphospholipid syndrome, and malignancies.
What percent of infectious endocarditis patients experience an embolic event?
30%
What size of vegetations is most consisent with high embolization risk?
>10 mm
What percent of infectious endocarditis cases have abscess formation?
35%
What is an abscess defined as in terms of echo?
Region of necrosis containing purulent material that forms a cavity
What is the primary site of abscess formation in prosthetic valve endocarditits?
The sewing ring (Primary site of infection)
If you have prosthetic valve rocking, what % of the circumferential ring has dehiscence?
>40%
What clinical signs are clinically suggestive of an abscess?
- Persistent bacteremia despite antibiotics
- Worsening heart failure
- New conduction block
- Pericarditis
What is the sensitivity and specificity of abscess?
87% sensitive
96% specific
Abscess of the aortic or mitral valve are easier to see?
Aortic (86%) > Mitral (43%)
What two substances are similar in echogenicity from vegetative material?
1. Thrombus
2. Pannus (a condition in which a layer of vascular fibrous tissue extends over the surface of an organ or other specialized anatomical structure)
How does abscess appear in the Mitral valve?
Echo density in the posterior mitral annulus
How does abscess appear in the Aortic valve?
Confined to AV plane
May extending into proximal aorta to involve anterior or posterior walls
How does a mitral aortic intervalvular fibrosa pseudoaneurysm appear?
Pulsatile Echo Free Space bounded by AMVL Base, Medial LA wall and posterior aortic root

How does a mitral aortic intervalvular fibrosa pseudoaneurysm open?
Into LVOT through dehiscence in the mitral aortic continuity
How are mitral aortic intervalvular fibrosa pseudoaneurysm dynamic?
Expand in systole
Collapse in diastole
What % of perforation occur in aortic valve?
50% of IE
What % of perforation occur in mitral valve?
15%
What % of IE have CHF?
60%