Endocarditis

Basic Principles

▪ Echocardiographic evaluation for endocarditis uses an integrated approach with transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE), depending on the clinical setting and the initial echocardiographic findings.
▪ The modified Duke criteria for infective endocarditis are the current clinical standard.
▪ The primary goals of the echocardiographic examination in a patient with suspected or known endocarditis are to:
- ○ Detect and describe valvular vegetations
- ○ Quantitate degree of valve dysfunction
- ○ Identify paravalvular abscess or other complications
- ○ Evaluate hemodynamics effects of valve dysfunction on ventricular size and function and on pulmonary pressures
- ○ Provide prognostic data on clinical course and need for surgical intervention

Key Points

□ Definite endocarditis is present when blood cultures are positive and diagnostic findings are present on echocardiography; these are the modified Duke major criteria for the diagnosis of endocarditis.
□ Diagnostic echocardiographic findings for endocarditis are one of the following:
- □ Typical vegetation on a valve or prosthetic material
- □ Paravalvular abscess
- □ New prosthetic valve dehiscence
- □ New valvular regurgitation
□ In the absence of major criteria (blood cultures and echocardiographic findings), the minor criteria for diagnosis of endocarditis are:
- □ Predisposing heart condition or intravenous drug use
- □ Fever
- □ Vascular phenomenon (arterial emboli, mycotic aneurysm, conjunctival hemorrhage, etc.)
- □ Immunologic phenomenon (glomerulonephritis, rheumatoid factor, etc.)
- □ Other microbiologic evidence
□ A diagnosis of definite endocarditis is based on the presence of two major, or one major plus three minor, or all five minor criteria. A diagnosis of possible endocarditis is based on one major plus one minor, or three minor criteria.

Step-By-Step Approach

Step 1: Review the Clinical Data

▪ Key clinical data in the patient undergoing echocardiography for suspected endocarditis are:
- ○ Blood culture results
- ○ History of underlying cardiac disease or intravenous drug use
- ○ Other evidence of endocarditis (fever, embolic events, PR interval prolongation)
- ○ Any contraindication to TEE
▪ The clinical data help focus the echocardiographic examination so that particular attention is directed toward:
- ○ Detection of right-sided vegetations in patients with a history of intravenous drug use
- ○ Comparison of the current study with previous examinations in patients with underlying valve pathology
- ○ Additional imaging, often with TEE, of prosthetic valves and pacer leads

Key Points

□ The sensitivity of echocardiography for detection of valve vegetations depends as much on the diligence of the exam as on image quality; therefore a pretest estimate of the likelihood of disease is helpful to the sonographer.
□ Review of previous imaging studies before performing the exam allows quick recognition of new abnormalities.
□ Clinical data are critical for interpretation of echocardiographic data. The echo appearance of a cardiac tumor, thrombus, and infected vegetation are similar—the final diagnosis is based on integration of echocardiographic and clinical data.
□ Clinical data determine the urgency and most appropriate initial diagnostic modality, as well as the need for any subsequent studies.

Step 2: Choose Transthoracic and/or Transesophageal Echocardiography (Table 14.1)

▪ Most centers perform TTE before TEE in patients with suspected endocarditis, but this decision depends on the clinical situation.

TABLE 14.1

Diagnostic Imaging in Infective Endocarditis
	TTE	TEE	Other	AHA/ACC 2014 ♥	ESC 2015 ♦
Diagnosis in Patients With Suspected Infective Endocarditis (IE)
All patients with clinically suspected IE	♥ ♦			I (B)	I (B)
Non-diagnostic TTE		♥ ♦		I (B)	I (B)
Prosthetic heart valve or intracardiac device		♦			I (B)
Repeat within 5-7 days if initial study negative and clinical suspicion remains high	♦	♦			I (C)
Staphylococcus aureus bacteremia without known source	♥ ♦			IIa (B)	IIa (B)
Persistent fever in patient with a prosthetic valve		♥		IIa (B)
Positive TTE (except right sided with good quality TTE)		♦			IIa (C)
Suspected paravalvular infection with suboptimal echo images			CT	IIa (B)	∗
Suspected prosthetic valve endocarditis			¹⁸F-FDG PET/CT		∗
Staphylococcus aureus bacteremia with known source (to detect possible cardiac involvement)		♥		IIb (B)
Follow-up on Medical Therapy
Change in signs or symptoms or concern for complications (new murmur, embolism, persisting fever, heart failure, abscess, AV block)	♥ ♦	♥ ♦		I (B)	I (B)
Routine follow-up for uncomplicated IE	♦	♦			IIa (B)
Perioperative Echocardiography
Intraoperative TEE in patients undergoing valve surgery for IE		♥♦		I (B)	I (B)
Following Completion of Therapy
Baseline study after treatment for IE is completed	♦				I (C)

From Otto CM: Textbook of clinical echocardiography, ed 6, Philadelphia, 2018, Elsevier. Summarized from Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP 3rd, Guyton RA, et al: 2014 AHA/ACC guideline for the management of patients with valvular heart disease, J Am Coll Cardiol 63(22):e57-e185, 2014; and Habib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta JP, et al: 2015 ESC guidelines for the management of infective endocarditis, Eur Heart J 36(44):3075-3128, 2015.

Fig. 14.1 Detection of valvular vegetations.TEE 2D (left) and color Doppler (right) views of the mitral valve in a patient with bacteremia shows a large mobile mass on the mitral valve that prolapses into the LA is systolic consistent with a vegetation. This typical vegetation is attached to the upstream side of the valve (atrial side of mitral valve), is irregular in shape, and has a chaotic pattern of motion that is separate from the normal motion of the valve tissue. Color Doppler shows associated moderate to severe regurgitation. This appearance is similar to a partial flail mitral leaflet; the final diagnosis integrates clinical and bacteriological data with the echo findings. Ao, Aorta.
▪ TTE imaging is followed by TEE if transthoracic images are nondiagnostic, if a prosthetic valve is present, or if the patient has a high risk of endocarditis.
▪ TEE is an appropriate initial diagnostic approach in patients with a prosthetic valve or other intracardiac devices (such as pacer leads).
▪ In a patient with suspected or known endocarditis, TEE is recommended if clinical data suggest paravalvular abscess.

Key Points

□ TEE is more sensitive for detection of valve vegetations compared with transthoracic imaging (a sensitivity of ≈90% vs. ≈70%) (Fig. 14.1).
□ TEE is more sensitive for detection of paravalvular abscess compared with transthoracic imaging (sensitivity greater than 90% vs. about 50%).
□ TEE is the preferred approach in patients with prosthetic valves or other intracardiac devices (such as pacer leads) for detection of vegetations and evaluation of valve dysfunction (Fig. 14.2).
□ Transthoracic imaging provides more reliable measurements of left ventricle (LV) size and ejection fraction, because images of the LV are often oblique or foreshortened on TEE views.
□ Transthoracic imaging provides more accurate Doppler evaluation of stenotic valves and estimation of pulmonary pressures, because TEE often results in a nonparallel intercept angle between the Doppler beam and high-velocity jet.
□ When TEE is contraindicated but endocarditis is suspected on clinical grounds, a repeat transthoracic study in 5 to 10 days has additive value, with the prevalence of diagnostic findings increasing from 20% on the initial study to 40% on the repeat examination.

Step 3: Examine Valve Anatomy to Detect Valvular Vegetations

▪ Valvular vegetations on echocardiography are seen as an abnormal, irregular mass attached to the valve apparatus (Fig. 14.3).
▪ Valvular vegetations typically are attached to the upstream side of the valve leaflet (e.g., atrial side of the mitral or tricuspid valve, LV side of aortic valve) (Fig. 14.4).
▪ Motion of a vegetation typically is chaotic, with a spatial range in excess of normal valve excursion and a temporal pattern of rapid oscillations (Fig. 14.5).

Fig. 14.4 Mitral valve vegetation.TTE (top) and TEE (bottom) images of the mitral valve show an echodensity on the atrial side of the leaflets, consistent with a vegetation. The TEE images more clearly show involvement of both leaflets on the biplane and 3D images. There is no evidence of paravalvular abscess.

Key Points

□ In addition to standard views of each valve, the image plane is slowly moved from side to side (or in a rotational sweep on TEE), because vegetations often are seen only in oblique views.
□ Zoom mode, a narrow sector, high transducer frequency, and harmonic imaging are used to enhance details of valve anatomy (Fig. 14.6).
□ An M-mode recording through suspected vegetation seen on two-dimensional (2D) imaging helps distinguish vegetation from an artifact or valve tissue, based on the pattern and speed of motion of the structure.
□ Vegetations may be missed on TTE; transesophageal imaging has a higher sensitivity for detection of vegetation due to improved image quality.
□ The relationship of the vegetation to valve anatomy may be better appreciated with three-dimensional (3D) imaging, but there are no data to suggest that 3D imaging improves diagnostic accuracy for endocarditis.
Fig. 14.5 M-mode of aortic valve vegetation.An indistinct echodensity adjacent to the aortic valve leaflets was seen in a patient referred for possible endocarditis. The M-mode shows fine oscillations of the mass in diastole, suggesting a vegetation rather than nonspecific leaflet thickening. Ao, Aorta.
□ Other valve masses may be mistaken for an infected vegetation, including (Fig. 14.7):
□ Valvular vegetations tend to decrease in size and increase in echogenicity with effective therapy. However, some vegetations may still be present years after active infection.

Step 4: Evaluate Valve Dysfunction Due to Endocarditis

▪ Vegetations are associated with distortion of valve anatomy and destruction of valve tissue, typically resulting in valve regurgitation (Fig. 14.8).
▪ The presence and severity of valve dysfunction are evaluated no differently than in a patient with valve disease of any cause (see Chapters 12 and 13).
▪ Valve regurgitation in a patient with endocarditis often is acute (hours to days), rather than chronic (months to years), in duration.

Key Points

□ Vegetations may impede complete valve closure, resulting in regurgitation at the coaptation plane with either native or prosthetic valves.
□ Valve destruction results in regurgitation due to leaflet perforation or deformity of the leaflet edge.
□ Regurgitation of prosthetic valves often is paravalvular due to infection in the annulus with valve dehiscence (Fig. 14.9).
□ About 10% of patients with endocarditis do not have significant valve regurgitation due to the location of the vegetation at the leaflet base, which does not impair valve function.
□ Rarely, a large vegetation causes stenosis due to obstruction of the native or prosthetic valve orifice by the vegetation mass.
□ Prosthetic valve stenosis can result from a small infected vegetation or thrombus impinging on normal disk excursion.

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Apr 23, 2020 | Posted by admin in CARDIOLOGY | Comments Off

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Thoracic Key

Fastest Thoracic Insight Engine

Endocarditis

Endocarditis

Basic Principles

Step-By-Step Approach

Step 1: Review the Clinical Data

Step 2: Choose Transthoracic and/or Transesophageal Echocardiography (Table 14.1)

Key Points

Step 3: Examine Valve Anatomy to Detect Valvular Vegetations

Step 4: Evaluate Valve Dysfunction Due to Endocarditis

Full access? Get Clinical Tree

Thoracic Key

Fastest Thoracic Insight Engine

Endocarditis

Basic Principles

Key Points

Step-By-Step Approach

Step 1: Review the Clinical Data

Key Points

Step 2: Choose Transthoracic and/or Transesophageal Echocardiography (Table 14.1)

Key Points

Step 3: Examine Valve Anatomy to Detect Valvular Vegetations

Key Points

Step 4: Evaluate Valve Dysfunction Due to Endocarditis

Key Points

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