282 S E C T I O N I V Pediatric Critical Care: Cardiovascular A B C D • Fig 29.21 Pericardiocentesis (A) Subcostal coronal imaging showing a needle (arrow) entering the pericardial space (B) Off-axis subcostal imaging showing pericardiocentesis needle (arrow) immediately adjacent to the heart (C) With injection of agitated saline, the pericardial effusion becomes partially opacified (arrows) while the right ventricular cavity remains dark, indicating that the needle is located within the pericardial space (D) Subcostal coronal image showing resolution of the effusion at conclusion of the pericardiocentesis endocarditis is often associated with indwelling catheters.86 When endocarditis is due to congenital heart disease, the lesion should be located on the downstream side of the abnormal blood flow, such as on the atrial side of an atrioventricular valve with regurgitation, or in the pulmonary artery of a patient with a patent ductus arteriosus Transthoracic echocardiography is the first-line tool for assessment of endocarditis in pediatrics TEE should be performed when transthoracic imaging is inadequate However, unlike in adults, TEE is not always required in children, as the thin chest wall allows for better image resolution by transthoracic imaging and smaller TEE with fewer imaging elements (piezoelectric crystals) embedded in the transducer head may not produce comparable resolution to that obtained by transthoracic imaging in young children Goals of echocardiography in suspected endocarditis are to (1) visualize any mass within the heart or major vessels; (2) characterize mass in terms of number, size, location, and mobility; and (3) assess for complications related to endocarditis, including valve regurgitation, valve perforation, chordal rupture, abscess formation, and dehiscence of prosthetic valve (Fig 29.22) Not all masses identified by echocardiography will be a vegetation, and it may be difficult to distinguish a vegetation from a thrombus or other intracardiac mass Vegetations typically are characterized as oscillatory masses, meaning that they move with high frequency and faster than surrounding heart structures In comparison, calcifications typically move with adjacent structures Thrombi and some tumors can be also oscillatory Additionally, endocarditis can be present without a vegetation visible by echocardiography Therefore clinical factors remain essential for an accurate diagnosis in endocarditis When endocarditis is present, echocardiographic findings can help determine whether surgical intervention is indicated based on findings such as left-sided vegetation greater than 15 mm in size, increasing vegetation size despite antibiotic therapy, highly mobile vegetation, persistent vegetation after systemic embolization event, valve perforation or rupture, significant valve regurgitation with heart failure, large abscess, or valve dehiscence.87 Serial echocardiography is an important part of the management of patients with a confirmed diagnosis Intracardiac thrombi can occur as a complication of an indwelling catheter, cardiomyopathy (low-flow areas), arrhythmia, or certain congenital heart diseases Echocardiography remains the primary imaging modality for assessment of cardiac thrombi.88 As in evaluation of vegetations, transthoracic echocardiography is used as the initial test in pediatrics TEE should be obtained when transthoracic image quality is not sufficient but is not required in all children Venous catheters leave behind a fibrin cast after removal (Fig 29.23) or cause intravascular thrombus formation or thrombi within the heart itself (Fig 29.24) Patients who have undergone the Glenn or Fontan procedure are at increased risk of venous thrombosis.89 Echocardiography remains the first-line CHAPTER 29 Echocardiographic Imaging A B C D • Fig 29.22 (A) Parasternal long-axis view tilted toward tricuspid valve showing a large vegetation on the atrial side of the septal leaflet (arrow) (B) Transesophageal image showing vegetation on mitral valve with perforation, dark space (arrow) (C) Color Doppler imaging shows severe mitral regurgitation through the perforation (D) Modified parasternal short-axis view showing two areas of abscess formation (blue arrows) surrounding the Sano shunt with stent in place (white arrow) in a patient with hypoplastic left heart syndrome A B • Fig 29.23 (A) On apical four-chamber view, a linear echogenicity is noted (arrow) that appears consis- tent with a catheter However, all previously placed catheters were removed consistent with this being a fibrin sheath cast from a previous catheter If there is concern regarding a fragment of catheter being left behind, a chest radiograph can be obtained In general, casts will be benign and gradually resolve over time (B) In a different patient, a small cast was noted to be attached to the atrial septum During diastole, the free end was seen to prolapse across the tricuspid valve, raising concern for possible embolic events to the pulmonary vasculature 283 284 S E C T I O N I V Pediatric Critical Care: Cardiovascular Embolic stroke may be a complication of an intracardiac thrombus or vegetation but also can be due to a paradoxical embolus of a venous thrombus across a patent foramen ovale (PFO) Detection of a PFO can be enhanced by intravenous injection of agitated saline At rest, a left-to-right shunt would be expected; thus performing a Valsalva maneuver to transiently increase systemic venous return and right atrial pressure improves detection of a PFO in patients who can cooperate Even with a Valsalva maneuver, echocardiography is not 100% sensitive for detection of a “probe-patent” PFO, but it is important to remember that a PFO is considered a normal finding.88 When a PFO is detected, it can be closed with a transcatheter device, but it remains controversial at this time whether device closure of PFO or medical anticoagulation is the better treatment option • Fig 29.24 Subcostal sagittal image showing thrombus extending into the right atrium (arrow) from a catheter in the superior vena cava • Fig 29.25 Apical four-chamber view showing a large thrombus, echo bright area (arrow) in the left ventricular apex of a patient with dilated cardiomyopathy (DCM) The apex is the most common location for thrombus formation in patients with DCM and can be difficult to visualize when small and adjacent to trabeculations or the cannula of a mechanical assist device diagnostic test, but echocardiography has lower sensitivity for thrombosis in this patient population, and alternative testing with CMR, cardiac CT or cardiac catheterization should be considered Venous thrombosis may contribute to superior vena cava syndrome, pleural effusions, protein-losing enteropathy, or plastic bronchitis Patients with a systemic-to-pulmonary-artery shunt are at risk for shunt thrombosis Patients who are shunt dependent for systemic or pulmonary venous blood flow should undergo emergent echocardiographic evaluation for any change in clinical status concerning for partial or complete obstruction of the shunt These include sudden drops in oxygen saturations (in the case of shuntdependent pulmonary blood flow) or cardiac output (in the case of shunt-dependent systemic blood flow), coupled with change in or loss of shunt murmur Intracardiac thrombi related to cardiomyopathy can occur in either ventricle, with thrombus typically located in the apex or adjacent to assist device driveline (Fig 29.25).90 Careful evaluation of the entire ventricular chamber is essential in assessing for small thrombi in these patients Serial echocardiography can help the decision to pursue surgical thrombectomy or to ensure resolution of the intracardiac thrombus with anticoagulation Peripheral vascular thrombosis is assessed by vascular ultrasound rather than echocardiography Kawasaki Disease and Coronary Artery Anomalies When performing echocardiography in any ICU patient with shock or new-onset cardiomyopathy, assessment of coronary arteries is a standard part of the evaluation to rule out acquired (e.g., Kawasaki disease [KD], severe acute respiratory syndrome coronavirus [SARS-CoV-2] infection–associated multisystem inflammatory syndrome in children) or congenital coronary artery anomalies as the underlying diagnosis The origin and proximal course of the coronary arteries should be visualized by both 2D and color Doppler imaging, with documentation of antegrade flow in diastole KD is an acute systemic vasculitis in which cardiovascular complications are a major contributor to morbidity and mortality both in the acute stage and in the long term.91 Although not part of the clinical findings used to define classic KD, cardiac findings of coronary artery aneurysm, myocarditis, pericarditis, valvar regurgitation, and aortic root enlargement may aid in the diagnosis of KD, especially in atypical cases (Fig 29.26) While most patients with KD will not require ICU treatment, up to 6% do.92 KD should be considered in any patient thought to be septic but with negative cultures Approximately 20% of patients with KD will have left ventricular dysfunction at presentation Typically, myocarditis associated with KD is mild, and the ventricular dysfunction responds to medical therapy but can be severe and prolonged in KD shock syndrome.93 The echocardiogram may confirm a diagnosis of KD in a patient with septic shock picture if coronary artery aneurysms are noted Children with KD typically are irritable; thus the initial study in an unsedated patient may be inadequate A sedated study should be obtained as soon as possible and within 48 hours for any patient in whom initial imaging was inadequate A coronary artery z-score of 2.5 or greater is used to define the presence of an aneurysm Coronary artery aneurysms in themselves not cause cardiac symptoms, but they can lead to myocardial ischemia secondary to thrombosis Even more rarely, the coronary artery may rupture Risk for thrombosis and rupture are greatest in the acute stage; repeat echocardiography twice weekly is reasonable in patients with large or giant aneurysms early in the disease course.91 Patients with coronary artery aneurysms are at risk for late development of coronary thrombosis or stenosis, with a direct relationship between coronary artery aneurysm size and risk.94 Coronary thrombosis may present with an acute myocardial infarction, cardiac arrest, or sudden death Young children with KD can have myocardial infarction without clinical symptoms,95 leading to development of cardiomyopathy CHAPTER 29 Echocardiographic Imaging A 285 B • Fig 29.26 Patient with Kawasaki disease with large aneurysm (arrow) of the right coronary artery (A) and moderate aneurysm (arrow) of left coronary artery (B) based on z-scores A B • Fig 29.27 (A) Apical four-chamber view showing a dilated C Therefore, any patient with a history of KD presenting to the ICU with signs or symptoms of myocardial infarction, cardiac arrest, or new-onset cardiomyopathy should undergo extensive evaluation of the coronary arteries beginning with echocardiographic assessment followed by more advanced imaging or cardiac catheterization as needed Congenital coronary artery anomalies are an infrequent cause of admission to the pediatric ICU The true incidence of congenital coronary arteries is difficult to determine, but isolated coronary artery abnormalities have been found in 1.3% of patients undergoing cardiac catheterization.96 A coronary artery anomaly that causes myocardial ischemia can lead to acute or chronic heart failure, arrhythmias, cardiac arrest, or sudden death left ventricle with echobright papillary muscle and mitral regurgitation Off-axis parasternal short-axis imaging shows a coronary artery arising from the pulmonary artery by twodimensional (B) and color Doppler imaging (C) Evaluation of the coronary arteries by echocardiography should be performed in any patient presenting to the ICU for these indications Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) (Fig 29.27) is estimated to affect in 300,000 live births.97 ALCPA has variable timing of presentation, but typically causes irritability with feeds in the first month of life due to myocardial ischemia, as pulmonary vascular resistance drops, resulting in coronary steal Ischemia then leads to development of a dilated cardiomyopathy characterized by echobright mitral valve papillary muscle and significant mitral regurgitation Detection prior to development of dilated cardiomyopathy is rare The possibility of an ALCAPA should be thoroughly evaluated in any infant presenting with dilated cardiomyopathy 286 S E C T I O N I V Pediatric Critical Care: Cardiovascular A B • Fig 29.28 (A) C Parasternal short-axis two-dimensional (2D) imaging shows the coronary artery (arrow) crossing between the pulmonary artery anteriorly and aorta with apparent origin from the right sinus of Valsalva and giving rise to the left anterior descending artery (circumflex artery not seen in this image) (B) Color Doppler imaging demonstrates blue color Doppler flow within the coronary artery, indicating flow away from the transducer consistent with the left coronary artery arising from the right sinus Due to low Nyquist limit, there is some aliasing of flow within the coronary artery (C) Transesophageal imaging with color comparison confirms the diagnosis of anomalous left coronary artery from the right sinus by 2D imaging (white arrow) and color Doppler imaging (yellow arrow) myocardial ischemia and sudden death AAOCA has been reported as the second leading cause of death in young athletes.98 Although anomalous origin of left coronary from right sinus is less common than anomalous right coronary from left sinus, it is more likely to cause sudden cardiac death.99 Echocardiography is the first-line diagnostic test for determining the origin of coronary arteries; however, obtaining the diagnostic imaging can be technically challenging and may require sedation in young children Advanced imaging, such as CT angiography or MRI, may be necessary.100 Intravascular Catheters • Fig 29.29 A parasternal short axis using color comparison showing anomalous origin of the right coronary artery from the left sinus of Valsalva by two-dimensional (white arrow) and color Doppler (yellow arrow) Note that the color Doppler flow in the right coronary artery is red, indicating flow toward the transducer as it crosses between the great arteries but also should be considered in older patients presenting with cardiac arrest, coronary ischemia, or dilated cardiomyopathy Although ALCAPA is the most common form of anomalous coronary originating from the pulmonary artery, isolated left anterior descending coronary artery, isolated circumflex coronary artery, and right coronary artery also may arise from the pulmonary artery Anomalous aortic origin of a coronary artery (AAOCA) can involve a left coronary originating from right sinus or a right coronary from left sinus (Figs 29.28 and 29.29) When the anomalous coronary artery courses between the great arteries, it is associated with risk of Ultrasonography can be useful for evaluation of intravascular catheters Vascular ultrasound is used for assessment of catheters in the periphery, but echocardiography can be used to assess catheter position and patency in the great vessels Assessment for thrombus is discussed earlier in this chapter Echocardiography can aid in positioning catheters and in manipulating catheters through intracardiac connections.101 Indications for echocardiographic evaluation of catheters include evaluation of signs or symptoms attributable to a catheter-related thrombus (e.g., persistent pleural effusions, facial edema), assessment of catheter tip position in a patient with new arrhythmias, and guidance of catheter position during a procedure (e.g., balloon atrial septostomy) Although it is not standard practice to obtain an echocardiogram to confirm the position of umbilical venous catheters, it is possible for the catheter to cross a PFO into the left atrium despite the appearance of proper position on chest radiograph (Fig 29.30), resulting in increased risk of systemic air emboli This highlights the appropriateness of assessing catheter position in any patient undergoing echocardiography for another indication ... anterior descending artery (circumflex artery not seen in this image) (B) Color Doppler imaging demonstrates blue color Doppler flow within the coronary artery, indicating flow away from the transducer... PFO is detected, it can be closed with a transcatheter device, but it remains controversial at this time whether device closure of PFO or medical anticoagulation is the better treatment option... mechanical assist device diagnostic test, but echocardiography has lower sensitivity for thrombosis in this patient population, and alternative testing with CMR, cardiac CT or cardiac catheterization