II.D

Echocardiographic Findings in Infective Endocarditis

36 cards

Notes

Modified Duke criteria (definite vs possible IE)

Definite IE:

2 major, OR
1 major + 3 minor, OR
5 minor criteria.

Possible IE:

1 major + 1 minor, OR
3 minor.

Major criteria

1. Positive blood cultures

2 separate BCx with typical organisms: viridans strep, S. aureus, S. bovis (S. gallolyticus), HACEK group, community-acquired enterococci without a primary focus.
OR persistently positive: BCx > 12 hr apart, or 3 of 3 / majority of ≥ 4 separate BCx (first and last drawn ≥ 1 hr apart).
OR single positive BCx for Coxiella burnetii, or phase 1 IgG anti-Coxiella titer > 1:800.

2. Evidence of endocardial involvement (echo)

Oscillating intracardiac mass on valve/supporting structure/path of regurgitant jet/implanted material with no alternative explanation.
Abscess.
New partial dehiscence of a prosthetic valve.
New valvular regurgitation (increase in a prior murmur is not sufficient).

Minor criteria

Predisposition (heart condition or IV drug use).
Fever > 38.0 °C (100.4 °F).
Vascular phenomena - major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, ICH, conjunctival hemorrhages, Janeway lesions.
Immunologic phenomena - glomerulonephritis, Osler nodes, Roth spots, rheumatoid factor.
Microbiologic evidence not meeting major criterion.

Detection sensitivity

Smallest left-sided vegetation detectable: TTE 5 mm, TEE 1 mm.
TTE sensitivity 62–82 %; specificity 91–100 %.
TEE sensitivity 87–100 %; specificity 91–100 %.
With Staph aureus bacteremia and a NEGATIVE TTE without clinical signs, the chance IE is missed if TEE is skipped is ~15 %.

Anatomic tendencies

Vegetations settle on the upstream (low-pressure) surface of the valve.
- Ventricular surface of AV in AI.
- Atrial surface of MV in MR.
Downstream-surface masses are more often degenerative (papillary fibroelastoma, chordal masses).
IE more common on previously abnormal (turbulent) valves.

Mimics of IE

Papillary fibroelastoma (typically on the aortic side of AV; small, pedunculated).
Myxomatous mitral valve disease.
Nonbacterial thrombotic (marantic) endocarditis - malignancy (esp. mucinous adenocarcinoma), SLE (Libman-Sacks).
Antiphospholipid syndrome - large valvular masses, "kissing" lesions at any location; tissue destruction usually absent (its presence should raise concern for IE).
Prosthetic valve thrombus.
Beam-width artifact.
Normal variants: Lambl's excrescences, Arantius nodules.

Perivalvular complications

Abscess

Localized abnormal thickening of perivalvular tissue or an echolucent cavity that does NOT communicate with cardiac chambers.
Most common location: aortic root and aorto-mitral intervalvular fibrosa.
Best view: PSAX of the aortic valve (TEE mid-esophageal 45–60°).
Early sign: abnormal thickening (echo-dense) of the aortic root > 10 mm; over time echolucency develops.
Complications: extrinsic compression of left main coronary artery → high-velocity diastolic LMCA flow; myocardial abscess → AV block (septal abscess); pericardial fistula.

Pseudoaneurysm

Abscess that has established communication with the aortic lumen - localized bulging (best seen in systole).

Fistula

Abscess erodes aortic root → communicates with another chamber.

Leaflet perforation

Origin of regurgitant jet away from the coaptation line → leaflet perforation.

Mitral valve aneurysm (from posteriorly-directed AI jet)

Localized systolic bulge of AMVL toward LA (expands in systole, collapses in diastole).
Perforation of aneurysm → MR (color shows systolic flow crossing into LA).
Repair with pericardial patch preferred over replacement.

Prosthetic valve endocarditis - special considerations

TEE is essential. Reverberations/shadowing limit TTE.
Infection often involves the sewing-ring area rather than a discrete valvular vegetation.
Look for: perivalvular regurg, dehiscence with rocking > 15°, annular bulging.

Indications for early surgery

Valve dysfunction with heart failure.
Resistant organism (Staph aureus, fungus).
Heart block (suggests abscess).
Perivalvular abscess.
Large mobile vegetation (> 10 mm) with severe valve disease.
Persistent bacteremia despite antibiotics.
Prosthetic valve endocarditis.
Recurrent embolization.
Right-sided TV vegetation > 2.5 cm → high embolic risk → replacement.

Antibiotic prophylaxis (2020 AHA/ACC) - highest-risk groups only

Prosthetic heart valves (including TAVR) or prosthetic material used in valve repair.
Prior IE.
Cardiac transplant with valvular dysfunction.
Congenital heart disease:
- Unrepaired cyanotic CHD (including palliative shunts).
- Repaired CHD with prosthetic material within 6 months.
- Repaired CHD with residual defects at/near prosthetic material.

Not recommended for TEE, upper endoscopy, colonoscopy, cystoscopy without ongoing infection.

Recommended before dental procedures involving gingival/periapical/oral mucosal manipulation.

Post-treatment findings

Successful ABX: vegetations shrink and become more echodense.
Persistence alone does NOT predict worse outcome.
Lack of vegetation regression after 4–6 weeks with progressive valve disruption → higher mortality.
< 10 % of affected valves regain normal structure after healing.

Cards

basicII.D-001
By modified Duke criteria, what combinations diagnose DEFINITE infective endocarditis?
→ 2 major, OR 1 major + 3 minor, OR 5 minor criteria.
basicII.D-002
By modified Duke criteria, what combinations diagnose POSSIBLE infective endocarditis?
→ 1 major + 1 minor, OR 3 minor criteria.
basicII.D-003
List the four echocardiographic findings that constitute the 'evidence of endocardial involvement' major Duke criterion.
→ 1) Oscillating intracardiac mass on valve or supporting structure, in the path of a regurgitant jet, or on implanted material without alternative explanation. 2) Abscess. 3) New partial dehiscence of a prosthetic valve. 4) NEW valvular regurgitation (increase in a preexisting murmur is not sufficient).
basicII.D-004
List the typical organisms whose growth on 2 separate blood cultures without a primary focus counts as a major Duke criterion.
→ Viridans streptococci, Staphylococcus aureus, Streptococcus bovis (gallolyticus), HACEK group, community-acquired enterococci.
basicII.D-005
What does 'HACEK' stand for?
→ Haemophilus species, Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans, Cardiobacterium hominis, Eikenella species, Kingella kingae. Fastidious Gram-negative organisms.
basicII.D-006
List three examples of vascular phenomena that count as minor Duke criteria.
→ Major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, Janeway lesions.
basicII.D-007
List three examples of immunologic phenomena as minor Duke criteria.
→ Glomerulonephritis, Osler nodes, Roth spots, rheumatoid factor.
basicII.D-008
What is the smallest left-sided vegetation detectable by TTE vs TEE?
→ TTE: ~5 mm. TEE: ~1 mm.
basicII.D-009
State TTE and TEE sensitivity for left-sided vegetations.
→ TTE: 62–82%. TEE: 87–100%. Specificity 91–100% for both.
basicII.D-010
In S. aureus bacteremia with a negative TTE and no clinical signs of IE, what is the approximate rate of missed IE if TEE is not performed?
→ ~15%. TEE is generally indicated in S. aureus bacteremia even when TTE is negative.
basicII.D-011
On which surface of the valve do IE vegetations typically settle?
→ The upstream (low-pressure) surface. Ventricular surface of the AV in AR. Atrial surface of the MV in MR. Downstream-surface masses are more often degenerative (fibroelastoma).
basicII.D-012
Where is a perivalvular aortic root abscess most commonly located, and what is the best imaging view?
→ Aortic root and aorto-mitral intervalvular fibrosa. Best view: PSAX of the aortic valve on TEE (mid-esophageal 45–60°).
basicII.D-013
What is the earliest echo sign of an aortic root abscess?
→ Abnormal echo-dense thickening of the aortic root (typically > 10 mm), later evolving into an echolucent cavity as the abscess matures.
basicII.D-014
A patient with aortic root abscess develops new complete heart block. What likely happened?
→ Extension of the abscess into the interventricular septum (myocardial abscess) — a highly lethal complication requiring urgent surgery.
basicII.D-015
An aortic root abscess causes high-velocity diastolic flow in the left main coronary artery. Why?
→ Extrinsic compression of the LMCA by the abscess narrows the vessel, producing high-velocity diastolic coronary flow.
basicII.D-016
Distinguish a pseudoaneurysm from an abscess in IE.
→ An abscess is a contained perivalvular cavity that does NOT communicate with cardiac chambers. A pseudoaneurysm is an abscess that HAS eroded into the aortic lumen (or an adjacent chamber) and communicates — localized bulging expands in systole.
basicII.D-017
How can you tell an aortic-valve endocarditis has caused a mitral valve aneurysm rather than isolated MR?
→ Posteriorly directed AR jet strikes the AMVL → seeds a satellite lesion → localized systolic bulge of AMVL toward the LA that collapses in diastole; often with perforation. Repair with pericardial patch preferred over replacement.
basicII.D-018
What tricuspid vegetation size threshold indicates high embolic risk and possible surgical replacement?
→ > 2.5 cm on the tricuspid valve — high embolic risk, often prompts surgical intervention.
basicII.D-019
List six indications for early surgery in native-valve endocarditis.
→ 1) Valve dysfunction with heart failure. 2) Perivalvular abscess/fistula. 3) Highly resistant organism (S. aureus, fungi). 4) Persistent bacteremia despite antibiotics. 5) Recurrent embolization. 6) Large (>10 mm) mobile vegetation with severe valve disease. Also new heart block.
basicII.D-020
List five conditions for which endocarditis antibiotic prophylaxis IS recommended (2020 AHA).
→ 1) Prosthetic heart valves (including TAVR) or prosthetic material used in valve repair. 2) Prior IE. 3) Cardiac transplant with valvular dysfunction. 4) Unrepaired cyanotic CHD. 5) Repaired CHD within 6 months of prosthetic material placement or with residual defects at/near the prosthetic.
basicII.D-021
Which procedures generally do NOT require IE prophylaxis in high-risk patients?
→ TEE, upper endoscopy, colonoscopy, and cystoscopy — as long as there is no active infection.
basicII.D-022
Is prophylaxis indicated for isolated mitral valve prolapse?
→ No. Isolated MVP is not on the list of high-risk conditions requiring dental IE prophylaxis.
basicII.D-023
After a successful antibiotic course, how do vegetations typically change?
→ They shrink in size and become more echo-dense. Persistence alone does NOT predict worse outcome. Failure to regress after 4–6 weeks combined with progressive valve dysfunction predicts worse outcomes.
basicII.D-024
What is Libman-Sacks endocarditis, and in what conditions is it seen?
→ Non-bacterial, sterile verrucous vegetations on valves — typically in SLE (Libman-Sacks) and antiphospholipid syndrome. Malignancy (esp. mucinous adenocarcinomas) causes 'marantic' NBTE, a related process.
basicII.D-025
Describe typical valvular findings of antiphospholipid syndrome (APLA).
→ Large valvular masses (mobile or broad-based, heterogeneous echogenicity), sometimes multiple 'kissing' lesions on either surface. Tissue destruction is usually ABSENT — if present, suspect superimposed IE.
basicII.D-026
With a membranous VSD, on which valve leaflet is IE most commonly seen?
→ Septal leaflet of the tricuspid valve — its proximity to the VSD jet exposes it to bacterial deposition. RVOT and subpulmonic vegetations can also occur.
basicII.D-027
How can caseous calcification of the mitral annulus be distinguished from a mitral annular abscess?
→ Caseous calcification shows an echolucent space within the calcified ring but WITHOUT a vegetation, leaflet perforation, or valve dysfunction. In abscess, expect associated vegetation, perforation, or severe valve dysfunction.
basicII.D-028
If TEE is initially negative but clinical suspicion for IE remains high, when should the study be repeated?
→ After 5–12 days of ongoing suspicion, ideally after antibiotics have been given time to stabilize or reveal the process.
basicII.D-029
Duke Criteria — what is the significance of Streptococcus gallolyticus (bovis) bacteremia beyond IE?
→ Highly associated with colon cancer (especially adenocarcinoma and adenomas). Any patient with S. bovis/gallolyticus bacteremia should undergo colonoscopy for colorectal malignancy screening.
basicII.D-030
Which infective endocarditis pathogen is most associated with IV drug use?
→ Staphylococcus aureus (both MSSA and MRSA). Predominantly right-sided IE (tricuspid valve). Pseudomonas and Candida also more common in IVDU.
basicII.D-031
Which pathogens have a predilection for prosthetic valve endocarditis in the first 60 days after surgery ('early PVE')?
→ Staphylococcus aureus and coagulase-negative staphylococci (usually S. epidermidis) — from perioperative contamination. Higher mortality than late PVE.
basicII.D-032
Vegetation size threshold on left-sided IE that increases embolic risk?
→ > 10 mm — increased embolic risk. > 15 mm mobile vegetation is a strong indication for early surgery, especially with prior embolism or valve dysfunction.
basicII.D-033
State the vegetation size threshold for right-sided (tricuspid) IE that increases surgical risk consideration.
→ > 2.5 cm on the tricuspid valve → high embolic (PE) risk and often prompts surgical intervention (valve repair or replacement).
basicII.D-034
How does aortic root abscess most commonly cause complete heart block?
→ Extension of the abscess into the interventricular septum near the AV node and bundle of His, disrupting conduction. New AV block in the setting of IE mandates urgent evaluation for perivalvular extension.
basicII.D-035
Which IE criteria change was made in the 2023 Duke-ISCVID modification?
→ Added F-18 FDG-PET/CT as a major criterion (18F-FDG uptake around a prosthetic valve after 90 days postoperative). Also refined some clinical criteria and modernized organism list.
basicII.D-036
How does Bartonella endocarditis differ clinically from typical IE?
→ Bartonella (henselae, quintana) causes 'culture-negative' subacute endocarditis. Requires special serologic testing or PCR. Homeless population and cat exposure are risk factors. Typically responds to doxycycline + gentamicin.