What is the recommended initial imaging modality for studying the heart in a child with Kawasaki disease?

Echocardiography is the Primary Imaging Modality for Cardiac Assessment in Kawasaki Disease

Echocardiography should be used as the initial imaging modality for cardiac assessment in children with Kawasaki disease due to its high sensitivity and specificity for detecting abnormalities of the proximal coronary artery segments. 1

Initial Echocardiographic Evaluation

• The initial echocardiogram should be performed as soon as the diagnosis of Kawasaki disease is suspected, but treatment should not be delayed by the timing of the study 1
• Sedation is frequently needed for children under 3 years of age and may be required in older, irritable children to obtain high-quality images 1
• If a poor-quality initial echocardiogram is obtained without sedation, a sedated study should be repeated within 48 hours after diagnosis and initial treatment 1
• An initial echocardiogram in the first week of illness is typically normal and does not rule out the diagnosis 1

Echocardiographic Imaging Standards

• Studies should be performed with appropriate high-frequency transducers and supervised by an experienced pediatric echocardiographer 1
• 2D imaging should be performed with the highest-frequency transducer possible, even for older children, to allow high-resolution detailed evaluation of the coronary arteries 1
• Studies should be recorded in a dynamic video or digital cine format to enable future review and comparison 1
• Multiple imaging planes and transducer positions are required for optimal visualization of all major coronary segments 1

Specific Areas of Assessment

• Coronary artery evaluation should focus on imaging the left main coronary artery (LMCA), left anterior descending (LAD), left circumflex, right coronary artery (RCA) (proximal, middle, and distal segments), and posterior descending coronary arteries 1
• Assessment of left ventricular function is essential as myocarditis is universal in acute Kawasaki disease 1
• Evaluation should include LV end-diastolic and end-systolic dimensions, shortening fraction, and ejection fraction 1
• The aortic root should be imaged and measured as mild aortic root dilation is common among patients with Kawasaki disease 1
• Presence or absence of pericardial effusion should be noted 1
• Valvular regurgitation, particularly of mitral and aortic valves, should be assessed using standard pulsed and color flow Doppler 1

Follow-up Echocardiographic Schedule

• For uncomplicated cases, echocardiographic evaluation should be performed at:
  • Time of diagnosis
  • 2 weeks after onset
  • 6-8 weeks after onset 1
• More frequent echocardiographic evaluation is needed for children at higher risk (persistently febrile or with coronary abnormalities, ventricular dysfunction, pericardial effusion, or valvular regurgitation) 1
• Research suggests that repeat echocardiography performed 1 year after onset is unlikely to reveal coronary artery enlargement in patients whose echocardiographic findings were normal at 4-8 weeks 1, 2

Limitations of Echocardiography

• While echocardiography is excellent for detecting coronary abnormalities, it has limitations in identifying thrombi and coronary artery stenosis 1
• Visualization of coronary arteries becomes progressively more difficult as a child grows and body size increases 1
• For patients with more complex coronary artery lesions, additional imaging modalities may be necessary 1

Alternative Imaging Modalities

• Coronary angiography offers more detailed definition of coronary artery anatomy and can detect coronary artery stenosis or thrombotic occlusion 1
• For patients with mild ectasia or small fusiform aneurysms on echocardiography, coronary angiography is unlikely to provide additional useful information 1
• Patients with more complex coronary artery lesions may benefit from coronary angiography after the acute inflammatory process has resolved (generally recommended 6-12 months after onset) 1
• Other modalities including magnetic resonance angiography (MRA), computed tomography (CT), intravascular ultrasound (IVUS), and transesophageal echocardiography may be valuable in selected patients 1, 3

Common Pitfalls to Avoid

• Relying on a single echocardiogram early in the disease course, as coronary abnormalities may develop later 1
• Failing to use sedation when needed, resulting in suboptimal imaging 1
• Inadequate visualization of all coronary segments due to improper technique or insufficient imaging planes 1
• Overlooking assessment of ventricular function, which is commonly affected in Kawasaki disease 1
• Assuming normal coronary arteries based on an initial echocardiogram in the first week of illness 1

By following these guidelines, clinicians can effectively use echocardiography as the primary imaging modality for cardiac assessment in children with Kawasaki disease, ensuring timely detection of coronary abnormalities and appropriate management.