**8.1 Coronary artery involvement**

The main features of coronary artery involvement are dilatation, aneurysm formation, lack of tapering of the distal coronary vessel and perivascular brightness. Aneurysms may be fusiform (spindle-shaped, gradual tapering from normal to dilated segment), saccular (spherical, acute transition from normal to dilated segment), ectatic (uniformly dilated long segment) or segmented (multiple dilatations joined by normal or stenotic areas) (Figure 1). The common sites of coronary involvement (from highest to lowest frequency) include the proximal left anterior descending artery (Figure 2), proximal right coronary artery (Figure 3 & 4), left main coronary artery (Figure 5), left circumflex branch (Figure 5), distal right coronary artery (Figure 6) and the junction of the right and posterior descending coronary artery. Takahashi et al reported that aneurysms were more likely to resolve if they were fusiform in nature and if the child was female and/or less than a year of age. Distal coronary artery aneurysms tended to regress more rapidly than aneurysms located in proximal coronary vessels (Takahashi et al., 1987).

Fig. 1. Illustrative example of coronary artery abnormalities.

The main features of coronary artery involvement are dilatation, aneurysm formation, lack of tapering of the distal coronary vessel and perivascular brightness. Aneurysms may be fusiform (spindle-shaped, gradual tapering from normal to dilated segment), saccular (spherical, acute transition from normal to dilated segment), ectatic (uniformly dilated long segment) or segmented (multiple dilatations joined by normal or stenotic areas) (Figure 1). The common sites of coronary involvement (from highest to lowest frequency) include the proximal left anterior descending artery (Figure 2), proximal right coronary artery (Figure 3 & 4), left main coronary artery (Figure 5), left circumflex branch (Figure 5), distal right coronary artery (Figure 6) and the junction of the right and posterior descending coronary artery. Takahashi et al reported that aneurysms were more likely to resolve if they were fusiform in nature and if the child was female and/or less than a year of age. Distal coronary artery aneurysms tended to regress more rapidly than aneurysms located in

**8. Cardiovascular involvement 8.1 Coronary artery involvement** 

proximal coronary vessels (Takahashi et al., 1987).

Fig. 1. Illustrative example of coronary artery abnormalities.

Fig. 2. Parasternal short axis echocardiographic image at the level of the mitral valve leaflets demonstrating an aneurysm of the left anterior descending artery.

Fig. 3. Parasternal short axis echocardiographic image showing a uniformly dilated proximal right coronary artery (RCA).

Echocardiography in Kawasaki Disease 145

Fig. 6. Off-axis parasternal short axis view demonstrating a fusiform aneurysm of the mid to

Virtually all patients with Kawasaki disease develop myocarditis to varying degrees during the acute phase, and over half of these patients develop acute transient left ventricular dysfunction (Ajami et al., 2010). Systolic left ventricular function should be routinely assessed. Regional wall motion abnormalities may occur if there is significant coronary artery involvement. Pericarditis may be reflected by the presence of a pericardial

distal right coronary artery (RCA) aneurysm

**8.2 Myo-pericarditis** 

effusion.

Fig. 4. Parasternal short axis image showing a giant aneurysm of the right coronary artery (RCA).

Fig. 5. Parasternal short axis view showing a uniformly dilated left main coronary artery (LMCA, 4.7mm) and dilated circumflex artery (Cx, 3.4mm). Ao = aorta

Fig. 4. Parasternal short axis image showing a giant aneurysm of the right coronary artery

Fig. 5. Parasternal short axis view showing a uniformly dilated left main coronary artery

(LMCA, 4.7mm) and dilated circumflex artery (Cx, 3.4mm). Ao = aorta

(RCA).

Fig. 6. Off-axis parasternal short axis view demonstrating a fusiform aneurysm of the mid to distal right coronary artery (RCA) aneurysm

#### **8.2 Myo-pericarditis**

Virtually all patients with Kawasaki disease develop myocarditis to varying degrees during the acute phase, and over half of these patients develop acute transient left ventricular dysfunction (Ajami et al., 2010). Systolic left ventricular function should be routinely assessed. Regional wall motion abnormalities may occur if there is significant coronary artery involvement. Pericarditis may be reflected by the presence of a pericardial effusion.

Echocardiography in Kawasaki Disease 147

Fig. 7. Magnetic resonance image using T2 weighted truFISP sequence demonstrating a

Cardiac stress testing may be used to identify reversible ischaemia and regional wall motion abnormalities during increased demand. Coronary perfusion abnormalities can be further assessed with exercise echocardiography, pharmacologic (dobutamine, dipyridamole or adenosine) stress echocardiography and exercise myocardial perfusion scans. The stress modality employed depends on the age of the child and local expertise, although practically speaking, pharmacologic stress echocardiography or exercise myocardial perfusion scans are the preferred techniques in the paediatric age group. If abnormalities of coronary segmental perfusion are found, the results may assist decision-

dilated left anterior descending (LAD) artery with a distal fusiform aneurysm.

**12. Functional assessment** 

making for further management.

### **8.3 Valvar involvement**

Myocardial inflammation may also involve valve tissue and lead to mitral, tricuspid or aortic regurgitation that is usually mild in nature. If severe mitral regurgitation is present, papillary muscle dysfunction and myocardial ischaemia should be assessed (Akagi et al., 1990). Mild aortic regurgitation is seen to persist in approximately 4% of patients with serial follow-up (Ravekes et al., 2001). Aortic root dilatation may occur as part of the overall vasculitis but is usually mild.
