16

effusions slowly develop.32 When pericardial reserve

volume is exhausted, additional pericardial fluid results

in a marked increase in pericardial pressure with

increased and equalized end-diastolic intracardiac pressures.36 Cardiac output may be maintained initially by a

compensatory sinus tachycardia prior to hemodynamic

deterioration, and other clinical features include pulsus

paradoxus, and hypotension in most but not all cases.

Echocardiography is essential in suspected cardiac tamponade, and clinical correlation with symptoms, heart

rate, and blood pressure are vital. A dilated inferior vena

cava (>2.1 cm) with minimal or no respiratory variation is

a useful tool to screen for tamponade (high sensitivity)

but does not confirm it, whereas diastolic right ventricular

collapse is the most specific finding. Right atrial inversion

beyond one-third of the cardiac cycle and marked respiratory variation in ventricular inflow (trans-mitral >30%

and trans-tricuspid >60%) are also features of cardiac

tamponade (Figure 10).3

Pericardiocentesis is therapeutically performed in

cases of impending or established cardiac tamponade,

especially in urgent or emergency settings with echocardiography guidance, and diagnostically when there

is concern for specific causes, such as bacterial, tuberculous, or malignant etiologies.7 In patients with an

inflammatory pericardial effusion and no concern for

tamponade, anti-inflammatory therapy should be pursued prior to pericardiocentesis. Anatomical approaches

to pericardiocentesis include subxiphoid, apical, and

parasternal. In an emergency, a subxiphoid or apical

approach is preferred. Otherwise, the approach should be

determined by where pericardial fluid is most accessible

with the least likelihood of damaging intervening vital

structures. Echocardiography, fluoroscopy, and/or

computed tomography may be utilized to guide the pericardiocentesis procedure. Surgical creation of a pericardial window is considered in select patients with

recurrent large pericardial effusions and/or cardiac tamponade despite prior pericardiocentesis. In certain rare

cases, radical pericardiectomy surgery may be indicated

for recurrent pericardial effusions, even following the

creation of a pericardial window, especially when there is

concomitant medically refractory constrictive pericarditis

or pericarditis.

4.3.3. Constrictive Pericarditis

Constrictive pathophysiology arises from a loss of pericardial elasticity, which impairs diastolic ventricular

filling and presents as a heart failure syndrome, typically

with normal ejection fraction.1,37 This condition can be

caused by irreversible pericardial thickening and fibrosis,

termed chronic constrictive pericarditis, or from

TABLE 8 Multimodality Cardiac Imaging Indications, Characterization, and Added Value for Evaluating Pericardial Effusions

Imaging Modality Echocardiography CCT CMR

Indications n First-line imaging n Second-line if echocardiography

inconclusive, or suspects secondary causes

n Second-line if echocardiography inconclusive,

or suspects pericarditis, pericardial malignancy, and/or CP

PEff characterization n Transudate: anechoic, homogenous,

free flowing

n Exudate/complex: echogenic,

heterogenous  loculations,

stranding or adhesions

n Transudate: 0-20 HU

n Exudate: 20-50 HU

n Hemorrhagic: >50-60 HU

n If very high HU: pericardial leakage

of contrast (eg, ruptured aortic

dissection)

n Chylous: –60 to –80 HU

n Transudate (homogenous):

Low SI on T1W or T2W BB

High SI on TW2/cine white-blood

T1 time >3,015 ms (1.5-T)

Jet-black on LGE PSIR

n Exudate/complex (nonhomogenous):

Intermediate/mixed SI on T1W or T2W BB

T1 time <3,015 ms (1.5-T)

n Acute hemorrhagic:

High SI in T1W or T2W BB

n Subacute hemorrhagic:

Intermediate SI in T1W or T2W BB

n Chronic hemorrhagic:

Low SI in T1W or T2W BB

Added value n Evaluate for coexisting CTP or ECP

n Guide pericardiocentesis

n TEE useful in detecting focal CTP

(eg, post–cardiac surgery)

n Identify secondary causes and

mimickers

n Assess for loculated PEff/focal CTP

(stable patients)

n May identify pericardial inflammation with late iodine enhancement

n CT-guided pericardiocentesis in

challenging cases

n Evaluate for coexisting pericarditis

n Evaluate for constriction if echocardiography

equivocal

n Useful when suspecting pericardial malignancy

n Assess for loculated PEff/focal CTP

(stable patients)

Adapted with permission from Klein et al.1

BB ¼ black-blood; CCT ¼ cardiac computed tomography; CMR ¼ cardiac magnetic resonance; CP ¼ constrictive pericarditis; CTP ¼ cardiac tamponade; ECP ¼ effusive constrictive

pericarditis; HU ¼ Hounsfield units; LGE ¼ late gadolinium enhancement; PEff ¼ pericardial effusion; PSIR ¼ phase-sensitive inversion-recovery; SI ¼ signal intensity;

T1W ¼ T1-weighted; T2W ¼ T2-weighted; TCP ¼ transient constrictive pericarditis; TEE ¼ transesophageal echocardiography.

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significant pericardial inflammation, termed transient

constrictive pericarditis. This distinction is crucial, as the

former usually requires surgical radical pericardiectomy,

whereas the latter may resolve spontaneously or with

anti-inflammatory therapy given for 3 to 6 months.38 In

areas where tuberculosis is endemic, it is the most common cause of constrictive pericarditis.39 Outside of this

setting, the most common cause is idiopathic, followed by

post–cardiac surgery and prior mediastinal radiation.1

Effusive constrictive pericarditis is a distinct entity

defined as persistent constrictive pathophysiology after

drainage of a pericardial effusion. Classically, this phenomenon was diagnosed invasively by a failure of the

right atrial pressure (or pericardial pressure) to decrease

following pericardiocentesis and is attributed to marked

inflammation of the visceral pericardium.40 Currently,

this condition is often diagnosed based on features of

constrictive pathophysiology with echocardiography that

appear after pericardial effusion drainage.41

The primary objectives of imaging here are to identify

constrictive pathophysiology and to assess the presence

and severity of pericardial inflammation. Echocardiography and CMR imaging play complementary roles, with

echocardiography serving as the primary and initial modality, whereas CMR offers the most comprehensive

assessment of pericardial inflammation.42 The predominant hemodynamic features of constrictive pathophysiology are dissociation of intrathoracic and intracardiac

pressures during respiration with resultant accentuated

interventricular dependence and elevated diastolic filling

FIGURE 9 Pericardial Effusion Sizing Evaluation by Echocardiography

Representative (A) small, (B) moderate, and (C) large PEffs (*). Representative (D) simple PEff with fibrin strands, (E) exudative PEff, and (F) malignant PEff (*) caused

by pericardial mesothelioma. Adapted with permission from Klein et al.1 PEff ¼ pericardial effusion; TTE ¼ transthoracic echocardiography.

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pressures in right- and left-side cardiac chambers. On

echocardiography, this hemodynamic abnormality results

in shift of the interventricular septum to the left with

inspiration, an E-wave predominant mitral inflow pattern,

an elevated medial e’ tissue Doppler velocity, a plethoric

inferior vena cava, and late-diastolic flow expiratory

reversal in the hepatic veins (Tables 10 and 11, Figures 11

and 12).43,44

With CMR imaging, early inspiratory septal shift during

a free-breathing cine white-blood acquisition is indicative

of constrictive pathophysiology. Pericardial thickness is

also readily assessed. Inflammation is characterized

based on whether there is increased pericardial signal on

T2-short tau inversion recovery imaging indicative of

edema and late gadolinium enhancement compatible

with neovascularization and inflammation. CCT evaluates

pericardial calcifications and defines thoracic anatomy

before pericardiectomy, particularly the relationship between cardiovascular structures and the sternum

(Tables 10 and 11).1 If clinical and imaging data are

incongruent, a detailed invasive hemodynamic evaluation should be performed with right and left heart catheterization, including an assessment for respiratory

FIGURE 10 Echocardiography Signs of Cardiac Tamponade

(A) TTE in parasternal long-axis view featuring moderate-to-large PEff (*). (B) Parasternal long-axis and short-axis views demonstrate end-diastolic right ventricular

free wall collapse. Significant respirophasic tricuspid (C) and mitral (D) inflow velocity variation is noted, and there is a plethoric IVC (E). Adapted with permission from

Klein et al.1 Exp ¼ expiration; Insp ¼ inspiration; IVC ¼ inferior vena cava; PEff ¼ pericardial effusion; TTE ¼ transthoracic echocardiography.

TABLE 9

Recommendations for Multimodality Cardiac

Imaging Evaluation and Management for

Pericardial Effusions and Cardiac Tamponade

Recommendation Class

TTE to identify pericardial effusion and assess for cardiac

tamponade

Recommended

CCT/CMR or transesophageal echocardiogram to confirm

diagnosis of pericardial effusion when clinically indicated if

TTE inconclusive

Recommended

CCT/CMR to assess for secondary causes of pericardial effusion

when clinically indicated

Reasonable

CCT/CMR for routine assessment of cardiac tamponade Not

recommended

Transesophageal echocardiogram/CCT to confirm clinical

diagnosis of focal cardiac tamponade in cases of high

suspicion with unrevealing/equivocal TTE

Recommended

TTE for surveillance of pericardial effusion (atleast moderate in size) Reasonable

Pericardiocentesis for cardiac tamponade Recommended

Pericardiocentesis for pericardial effusion without tamponade Not

recommended

Pericardial window after prior pericardiocentesis for recurrent

large pericardial effusion and cardiac tamponade

Reasonable

Adapted with permission from Klein et al.1

CCT ¼ cardiac computed tomography; CMR ¼ cardiac magnetic resonance;

TTE ¼ transthoracic echocardiography.

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discordance in left and right ventricular systolic pressures

using systolic area index (Figure 13).45,46 Table 12 compares the characteristics of constrictive pericarditis with

cardiac tamponade and restrictive cardiomyopathy.

For patients with underlying pericardial inflammation

as in transient constriction, anti-inflammatory therapy

should be initiated before considering pericardiectomy

(Figure 14).48 This approach may resolve the constrictive

pathophysiology, or if pericardiectomy remains indicated,

facilitates a more successful surgery on a less-inflamed

pericardium.38 In tuberculous constrictive pericarditis,

antituberculous therapy may resolve constrictive pathophysiology, and corticosteroids may enhance clinical

improvement.49 In patients with chronic constrictive

pericarditis and heart failure, diuretic therapy can treat

volume overload but does not alter the natural history.

Goal-directed heart failure therapy may be implemented,

although evidence is limited. Surgical radical pericardiectomy is preferred, with resection of the entire

pericardium—including anterior, diaphragmatic and posterior segments—on cardiopulmonary bypass, and should

be performed at experienced tertiary surgical centers for

optimal clinical outcomes.38

4.3.4. Pericarditis in Oncologic Patients

Pericardial involvement in the setting of known malignancy can occur with direct spread or hematologic or

lymphatic dissemination.50 Most pericardial metastases

are identified as part of a staging chest computed tomography or positron emission tomography-computed

tomography study. Frequently, the presence of new

pericardial effusion or nodularity in staging imaging

studies is the first clue for pericardial malignant

involvement. The presence of hemorrhagic or complex

pericardial effusion increases the likelihood of pericardial

metastasis in that setting. Symptoms of pericardial

metastasis, if present, are related to associated pericardial

TABLE 10 Multimodality Imaging Features of

Constrictive Pericarditis

TTE CCT CMR

n Respirophasic ventricular dependence/septal

shift

n E-wave predominant

LV filling with respirophasic variation

n Dilated inferior vena

cava with <50%

collapse

n Hepatic vein enddiastolic expiratory

reversal flow velocity/

forward flow velocity

$0.8

n Normal or increased

medial mitral annular e’

velocity (>8 cm/s)

n Annulus reversus

(medial > lateral e’

mitral annular velocity)

n Loss of superior vena

cava systolic flow

variation

n Respirophasic variation

across mitral and

tricuspid valve E-wave

inflow velocities

(>25% and >40%,

respectively)

n Increased

pericardial

thickness

n Pericardial

calcification

n Increased pericardial

thickness

n Respirophasic ventricular dependence on

free breathing cine

white-blood sequences

n Wall tethering and

conical deformity of

the ventricle on cinewhite blood and

tagging sequences

n Inflammation LGE and

edema on T2-STIR (in

inflammatory TCP)

No single isolated imaging finding is diagnostic of CP; a constellation of findings in

conjunction with clinical features of CP is required to make the diagnosis. Adapted with

permission from Klein et al.1

CCT ¼ cardiac computed tomography; CMR ¼ cardiac magnetic resonance; CP ¼

constrictive pericarditis; LGE ¼ late gadolinium enhancement; LV ¼ left ventricular;

STIR ¼ short tau inversion recovery; TCP ¼ transient constrictive pericarditis; TTE ¼

transthoracic echocardiography.

TABLE 11

Recommendations for Multimodality Cardiac

Imaging Evaluation and Management for

Constrictive Pericarditis

Recommendation Class

Noninvasive hemodynamic assessment by TTE for the

diagnosis of constrictive pericarditis and effusive

constrictive pericarditis

Recommended

CMR to provide supportive evidence of constrictive

pericarditis, especially when TTE inconclusive

Reasonable

CMR to identify pericardial inflammation as an etiology

of for constrictive pericarditis

Recommended

CCT to identify pericardial calcifications as supplementary

evidence for constriction, and for preoperative

evaluation for pericardiectomy surgery

Reasonable

Invasive cardiac catheterization for the diagnosis of

constrictive pericarditis, where noninvasive methods

are nondiagnostic or equivocal

Recommended

First-line treatment of inflammatory constrictive

pericarditis with anti-inflammatory therapy

Recommended

Diuretics for symptomatic treatment of constrictive

pericarditis

Reasonable

Radical surgical pericardiectomy for noninflammatory

constrictive pericarditis and inflammatory constrictive

pericarditis failing anti-inflammatory therapy

Recommended

Partial anterior and/or diaphragmatic pericardiectomy for

constrictive pericarditis

Not recommended

Adapted with permission from Klein et al.1

CMR ¼ cardiac magnetic resonance; CCT ¼ cardiac computed tomography; TTE ¼

transthoracic echocardiography.

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