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Echocardiography in Kawasaki Disease
Echocardiography in Kawasaki Disease Richard A. Meyer, MD, Cincinnati, Ohio
Two-dimensional echocardiography is the pinion of diagnostic procedures utilized to characterize the coronary arteries in Kawasaki disease. This article demonstrates the usual plans of interrogation used to systematically image the segments of the coronary arterial tree. It illustrates aneurysm formation in patients of various ages, the development of thrombosis in an aneurysm, and recanalization of the thrombosed arteries. The functional assessment and limitations of the technique are also addressed. (JAM Soc EcHo 1989;2:269-75.)
The purpose of this article is to evaluate the current status of echocardiography for assessing patients with Kawasaki disease. Since its initial description in 1967, this systemic inflammatory disease (characterized by persistent fever, mucocutaneous manifestations, cervical adenopathy, and cardiovascular involvement), has become more prevalent in the United States. Although the cause still is not entirely clear, a serious complication of Kawasaki disease has been the formation of coronary artery aneurysms that may result in coronary thrombosis with obstruction and ultimately myocardial infarction. Fortunately this complication occurs in only about 15% of all patients. Although the early administration of intravenous gamma globulin has further reduced that complication significantly in patients older than age 1 year/ the role of various therapeutic regimens on outcome is undear. 2 Nevertheless, two-dimensional echocardiography remains the mainstay of diagnostic procedures to characterize the state of the coronary arteries. IMAGING TECHNIQUE
Visualization of coronary arterial aneurysms in infants and children with Kawasaki disease with twodimensional echocardiography has been reported as early as 1979 by Yoshikawa et al. 3 and Hiraishi et al. 4 These authors were able to record aneurysms of the left main coronary artery and right proximal coronary artery from the precordial long-axis and short-axis views. Admittedly, the technology at the From the Division of Cardiology, Children's Hospital Medical Center, and the Department of Pediatrics, University of Cincinnati. Reprint requests: Richard A. Meyer, MD, Division of Cardiology, ASB-4, Children's Hospital Medical Center, Elland & Bethesda Avenues, Cincinnati, OH 45229.
time did not permit the high resolution and "pretty'' pictures to which we have become accustomed, but detection and approximation of the size of the aneurysm were possible. These two articles were primarily feasibility studies that opened the way for more in-depth studies. In 1982, Yoshida et al. 5 took a new approach and were able to demonstrate peripheral right coronary aneurysms from a subcostal view. The diagnosis and characterization of the aneurysms as far as size, shape, and anatomic position correlated well with angiocardiograms. However, from this subcostal approach, imaging of a normal coronary artery was not possible. Nevertheless, these authors 5 had demonstrated that it was possible to detect peripheral right coronary aneurysms, and in 1984 a systematic approach to visualize in detail both the right and left coronary artery anatomy was published by Satomi et al. 6 This protocol utilized seven echographic planes, which included the short-axis aortic root plane, long-axis mitral valve plane, longaxis tricuspid valve plane, apical four-chamber plane, sagittal right atrial plane, ftontal tricuspid valve plane, and finally the short-axis mitral valve plane. With a similar systematic approach to examine the coronary arteries (Figure 1) we found in a prospective study that the sensitivity, specificity, positive predictive value, and negative predictive value exceeded 97% when the entire coronary artery system was taken into account. 7 There was a marked improvement in our accuracy from 1982 through 1983 compared with the time period of 1978 to 1981, presumably because of improved instrumentation and our learning curve. Our greatest difficulty occurred in detecting aneurysms of the distal portions of the left anterior descending and circumflex coronary arteries. Part of the difficulty in making the diagnosis of a coronary artery aneurysm is in the definition of a coronary artery aneurysm. The criteria for an aneu269
journal of the American Society of Echocardiography
270 Meyer
Figure 1 Various planes used to interrogate coronary arterial tree. A, Precordial short-axis view of great vessel illustrating plane used for artaining proximal right coronary artery. B, Change in short-axis plane to record left main artery. C, Higher position on chest with inferior inclination to obtain bifurcation of left main artery into left anterior descending and left circumflex arteries. D, Apical view used to obtain distal third of right coronary artery. E, Subcostal four-chamber view of plane used to record middle segment of right coronary artery in cross section. F, Plane used to record long-axis view of middle segment of right coronary artery by turning transducer about 90 degrees clockwise or counterclockwise. AO, Aorta; LA, left atrium; LCA, left coronary artery; LV, left ventricle; PA, pulmonary artery; RA, right atrium; RCA, right coronary artery; R V, right ventricle.
rysm depended on the criteria published in a 1985 report by the Research Committee on Kawasaki Disease of the Ministry of Health and Welfare in Japan. The report indicated that an aneurysm should be defined as an increase in the coronary internal diameter to more than l.S times the adjacent vessel diameter. In addition, it was also believed that an absolute internal diameter greater than 3 mm con-
stituted dilation of that coronary artery. However, normal values and a profile of coronary arteries in children were not available untill986, when Arjunan et al. 8 published values and characterized the profile for the proximal coronary artery caliber in normal children. In addition to the normal internal dimen· sions that ranged from 2 to 5 mm from infants to adolescents, it was found that the caliber of each
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271
Figure 2 Echocardiogram from 3-year-old patient with Kawasaki disease but no aneurysms. A, Left coronary artery (LCA) dimension at upper limit of normal. B, Right coronary artery (RCA) dimension at lower limit of normal. AO, Aorta; SAX, short-axis.
Figure 3 Echocardiogram from patient with Kawasaki disease demonstrating uniform caliber of left main branch bifurcating into left anterior descending (LAD) and circumflex (CFX) branches.
artery remained uniform from its origin to its distal extent. Aneurysms tend to narrow suddenly or taper gradually from a much larger size to a normal caliber. This feature has become important to recognize, since some patients have a perfectly normal dominant coronary artery system that is larger in caliber than its smaller contralateral coronary artery (Figure 2). With the advent of higher frequency transducers focused in the near and medium fields the imaging of coronary arteries, particularly in the young, has steadily improved. This technology and additional scanning planes have improved our ability to record with greater accuracy the anatomy of the coronary arteries (Figure 3), in particular the distal segments (Figures l, F, 4 and 5). Thus a diagnosis of aneurysm formation can be established and the fate of these aneurysms followed. Fortunately many of these lesions resolve, and the regression can be monitored by echocardiography in many instances. 9
Figure 4 Echogram showing dilated fusiform aneurysm of distal third segment of right coronary artery measuring only 0.41 em. LV, Left ventricle; RA, right atrium; R V, right ventricle.
Figure 5 Echogram from subcostal four-chamber view demonstrating saccular aneurysm in cross section of middle third of right coronary artery (arrow). LV, Left ventricle; RA, right atrium; R V, right ventricle.
272
Jo urnal of dte American Society of Echocardiography
Meyer
Figure 6 Echocardiograms from 6-week-old male patient with Kawasaki disease demonstrating development and progression of aneurysms in right and left coronary arteries. A, Small but irregular lumen of right coronary artery (arrows). B, Development of aneurysm of same artery (arrow). C, Development of thrombus in further enlarged right coronary artery (RCA, arrow) . D, Relatively normal left main and anterior descending arteries (arrows). E, Development of thrombus in large aneurysm of left anterior descending artery (arrow).
Not only has our ability to image the coronary arteries and aneurysms improved, but our ability to detect thrombus formation (Figure 6) and the subsequent coronary artery stenosis has also improved. In addition, the recanalization process of the obstructive thrombus after anticoagulant and enzyme
therapy can be monitored more accurately (Figure 7). The progression of the aneurysm to giant proportions (>8 mm) (Figure 8) dramatically increases the risk of thrombus formation, 10 although this 4-yearold patient has not developed a thrombus after l year.
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Figure 8 Echogram of 4-year-old patient showing development of giant aneurysms of both proximal right coronary artery (PRCA, arrow) and left anterior descending (LAD) coronary artery. Left main artery (arrow) is normal.
Figure 7 Recanalization of both (A) left coronary artery (LCA, arrow) and (B) right coronary artery (RCA) thrombus (arrow) in same patient as Figure 6.
In our experience, the younger the infant (that is, younger than 6 months) at the time of diagnosis, the more likely the aneurysms will progress to giant size and develop thrombus (Figure 9). This 2-month-old boy later developed thrombus within 1 to 2 weeks of aneurysm formation. For this reason, these infants are examined almost daily during the first week or lO days and then weekly until 6 weeks after diagnosis to detect the appearance of aneurysms and or thrombi. Although no consensus has been reached as to the frequency of echocardiographic examinations, the protocol that we follow in our institution for those patients without evidence of aneurysms beyond 6 weeks is to obtain echocardiograms at 12 weeks, 9 months, 12 months, 18 months, 24 months, and then 1 to 2 years routinely after that. FUNCTIONAL ASSESSMENT
To date, single-gated Doppler (pulsed) and multigated Doppler (color flow) have added little to the direct evaluation of the coronary artery in these patients. The signals are varied and unreliable for the most part and very inconsistent. This is not totally
Figure 9 Development of giant aneurysm in right proximal coronary artery (arrows) of 2V2-month-old male patient who later developed a thrombus. Ao, Aorta.
unexpected, since the plane of interrogation of these arteries is for the most part perpendicular. In addition, the vessels are small, and flow characteristics do not lend themselves to meaningful information. Perhaps as time goes on these limitations will be overcome and greater functional data obtained. Conversely, Doppler clearly is helpful in assessing the presence ofvalvar regurgitation 11 . 13 (Figure 10). The aortic and tricuspid valves are affected in about 5% of patients. Most often the valvulitis is mild and resolves spontaneously. In addition to the valvar regurgitation, it also has been recognized that systolic and diastolic functional abnormalities exist in these patients. 14•15 This is not surprising, since these patients have microscopic changes in their coronary arteries and myocardium consistent with the inflammation associated with this disease. 16. 17 The issue of whether long-term left ventricular functional disability exists is not totally re-
Journal of the American Society of Echocardiography
274 Meyer
Doppler evidence of mitral valve regurgitation (arrows) that subsequently resolved in this 6-week-old male infant.
Figure 10
Pericardia! effusion during acute phase of illness in 6-month-old female patient.
Figure 11
solved. Nevertheless, evaluation of left ventricular dysfunction still depends primarily on M-mode and two-dimensional area shortening along with regional wall motion analysis. Most often the patients who have ventricular dysfunction also have effusions (Figure ll) that resolve with antiinflammatory treatment. The fate of the coronary arteries after resolution of the aneurysms is not known. One approach has been to evaluate the change in the caliber of the coronary artery between systole and diastole with angiographic techniques and densitometry. 18 Twodimensional directed M-mode measurements of the coronary arteries in patients with resolving aneurysms are being investigated, but data from such studies are not yet available. LIMITATIONS
Despite the advances in instrumentation and broadening of our understanding of the anatomy and var-
Selective coronary arteriograms of6-week-old male infant demonstrate near total occlusion of right (A) coronary arteries and left (B) circumflex artery, which was not detected by echocardiography. Patient later developed segmental wall motion abnormalities and myocardial infarction. Figure 12
ious planes of interrogation by echocardiography, limitations still exist. Many portions of the coronary arterial tree are still inaccessible to echocardiographic visualization. It is not possible to visualize many segments of the distal anterior descending, circumflex, or posterior descending branches. In addition, obstruction to flow from a thrombus is most difficult to assess. As alluded to by Pahl et al. 19 recently, total coronary occlusion by a thrombus may not be possible to detect echocardiographically. Either the area
Volume 2 Number4 July-August 1989
of stenosis is not visualized by echocardiography, or if it is visualized, it is not yet possible to determine whether there is occlusion to flow of that vessel. In addition, the occlusion may not produce symptoms. These two issues still plague the echocardiographer, but perhaps in time they may be overcome. Fortunately with rare exceptions, the proximal coronary arterial branches are involved whenever coronary artery aneurysms develop, regardless of the distal sites that are also involved. This is why we have been able to depend on echocardiography as a screening tool to detect the development of aneurysms; however, we still rely on selective coronary arteriography (Figure 12) to characterize the extent and nature of the aneurysms and their progression. SUMMARY
Since the early publications demonstrating the utility of echocardiography to image the coronary arteries in patients with Kawasaki disease, great strides have been made in instrumentation and imaging techniques, which permit better imaging capabilities and more accurate assessment of the arteries. Twodimensional imaging remains the keystone in the echocardiographer's armamentarium for evaluating this disease. The crucial element of the disease is the development of coronary artery aneurysms with subsequent thrombus formation and occlusion leading to myocardial ischemia and infarction. Echocardiography stil provides the simplest and most costeffective tool for evaluating the associated lesions and sequelae of this disease. However, when an aneurysm develops, selective angiography should be performed, although angiography in some cases has failed to show the extent of the aneurysm because of its limitation in visualizing the wall of the arteries. By the same token the converse is true; echocardiography may fail to show occlusion of flow in the arteries. Echocardiography and angiography must be used together prudently in these patients. As time goes on, advances in two-dimensional imaging, Doppler, and ideally tissue characterization will allow even greater accuracy in defining and characterizing the coronary arterial tree and myocardium of these patients.
REFERENCES l. Newburger JW, Takahashi M, Bums JC, et al. The treatment of Kawasaki syndrome with intravenous gamma globulin. N Eng! J Med 1986;315:345-7.
Echo in Kawasaki disease 275
2. Bierman FZ, Gersony WM. Kawasaki disease: clinical perspective. J Pediatr 1987;111:789-93. 3. Yoshikawa J, Yanagihara K, Owaki T, et al. Cross-sectional echocardiographic diagnosis of coronary artery aneurysms in patients with mucocutaneous lymph node syndrome. Circulation 1979;59:133-9. 4. Hiraishi S, Yashiro K, Kusano S. Noninvasive visualization of coronary arterial aneurysm in infants and young children with mucocutaneous lymph node syndrome with twodimensional echocardiography. Am J Cardiol1979;43: 122533. 5. Yoshida H, Maeda T, Funabashi T, et al. Subcostal twodimensional echocardiographic imaging of peripheral right coronary artery in Kawasaki disease. Circulation 1982; 65:956-65. 6. Satomi G, Nakamura K, Narai S, et al. Systematic visualization of coronary arteries by two-dimensional echocardiography in children and infants: evaluation in Kawasaki disease in coronary arteriovenous fistulas. Am Heart J 1984; 107:497505. 7. Capannari TE, Daniels SR, Meyer RA, et al. Specificity and predictive value of two-dimensional echocardiography in detecting coronary artery aneurysms in patients with Kawasaki disease. JAm Coil Cardiol 1986;7:355-60. 8. Arjunan K, Daniels SR, Meyer RA, et al. Coronary artery caliber in normal children and patients with Kawasaki disease but without aneurysms: an echocardiographic and angiographic study. JAm Coil Cardiol1986;8:1119-24. 9. Takahashi M, Mason W, Lewis AB. Regression of coronary artery aneurysms in patients with Kawasaki syndrome. Circulation 1987;75:387-94. 10. Tatara K, Kusakawa S. Long-term prognosis of giant aneurysm in Kawasaki disease: an angiographic study. J Pediatr 1987;111:705-10. 11. Nakano H, Ueda K, Saito A, et al. Dapper detection on tricuspid regurgitation following Kawasaki disease. Pediatr Radio! 1986;16:123-5. 12. Nakano H, Nojima K, Saito A, et al. High incidence of aortic regurgitation following Kawasaki disease. J Pediatr 1985; 107:59-63. 13. Gidding SS, Shulman ST, Ilbawi M, et al. Mucocutaneous lymph node syndrome (Kawasaki disease): delayed aortic and mitral insufficiency secondary to active valvulitis. J Am Coil Cardiol 1986;7:894-7. 14. Anderson TM, Meyer RA, Kaplan S. Long-term echocardiographic evaluation of cardiac size and function in patients with Kawasaki disease. Am Heart J 1985;110:107-15. 15. Nakano H, Ueda K, Saito A, et al. Left ventricular systolic function in children with coronary arterial lesion following Kawasaki disease. Heart Vessels 1985;1:89-93. 16. Yutani C, Go S, Karniya T, et al. Cardiac biopsy of Kawasaki disease. Arch Pathol Lab Med 1981;105:470-3. 17. Kohr RM. Progressive asymptomatic coronary artery disease as a late fatal sequela of Kawasaki disease. J Pediatr 1986;108:256-9. 18. Kurisu Y, Azurni T, Sugahara T, et al. Variation in coronary arterial dimension (distensible abnormality) after disappearing aneurysm in Kawasaki disease. Am Heart J 1987; 114:532-8. 19. Pahl E, John M, Clendaniel J, et al. The importance of angiography in assessment and follow-up of coronary abnormalities in Kawasaki disease [Abstract]. J Am Coil Cardia! 1988;11:29A.
Two-dimensional echocardiography is the pinion of diagnostic procedures utilized to characterize the coronary arteries in Kawasaki disease. This article demonstrates the usual plans of interrogation used to systematically image the segments of the coronary arterial tree. It illustrates aneurysm formation in patients of various ages, the development of thrombosis in an aneurysm, and recanalization of the thrombosed arteries. The functional assessment and limitations of the technique are also addressed. (JAM Soc EcHo 1989;2:269-75.)
The purpose of this article is to evaluate the current status of echocardiography for assessing patients with Kawasaki disease. Since its initial description in 1967, this systemic inflammatory disease (characterized by persistent fever, mucocutaneous manifestations, cervical adenopathy, and cardiovascular involvement), has become more prevalent in the United States. Although the cause still is not entirely clear, a serious complication of Kawasaki disease has been the formation of coronary artery aneurysms that may result in coronary thrombosis with obstruction and ultimately myocardial infarction. Fortunately this complication occurs in only about 15% of all patients. Although the early administration of intravenous gamma globulin has further reduced that complication significantly in patients older than age 1 year/ the role of various therapeutic regimens on outcome is undear. 2 Nevertheless, two-dimensional echocardiography remains the mainstay of diagnostic procedures to characterize the state of the coronary arteries. IMAGING TECHNIQUE
Visualization of coronary arterial aneurysms in infants and children with Kawasaki disease with twodimensional echocardiography has been reported as early as 1979 by Yoshikawa et al. 3 and Hiraishi et al. 4 These authors were able to record aneurysms of the left main coronary artery and right proximal coronary artery from the precordial long-axis and short-axis views. Admittedly, the technology at the From the Division of Cardiology, Children's Hospital Medical Center, and the Department of Pediatrics, University of Cincinnati. Reprint requests: Richard A. Meyer, MD, Division of Cardiology, ASB-4, Children's Hospital Medical Center, Elland & Bethesda Avenues, Cincinnati, OH 45229.
time did not permit the high resolution and "pretty'' pictures to which we have become accustomed, but detection and approximation of the size of the aneurysm were possible. These two articles were primarily feasibility studies that opened the way for more in-depth studies. In 1982, Yoshida et al. 5 took a new approach and were able to demonstrate peripheral right coronary aneurysms from a subcostal view. The diagnosis and characterization of the aneurysms as far as size, shape, and anatomic position correlated well with angiocardiograms. However, from this subcostal approach, imaging of a normal coronary artery was not possible. Nevertheless, these authors 5 had demonstrated that it was possible to detect peripheral right coronary aneurysms, and in 1984 a systematic approach to visualize in detail both the right and left coronary artery anatomy was published by Satomi et al. 6 This protocol utilized seven echographic planes, which included the short-axis aortic root plane, long-axis mitral valve plane, longaxis tricuspid valve plane, apical four-chamber plane, sagittal right atrial plane, ftontal tricuspid valve plane, and finally the short-axis mitral valve plane. With a similar systematic approach to examine the coronary arteries (Figure 1) we found in a prospective study that the sensitivity, specificity, positive predictive value, and negative predictive value exceeded 97% when the entire coronary artery system was taken into account. 7 There was a marked improvement in our accuracy from 1982 through 1983 compared with the time period of 1978 to 1981, presumably because of improved instrumentation and our learning curve. Our greatest difficulty occurred in detecting aneurysms of the distal portions of the left anterior descending and circumflex coronary arteries. Part of the difficulty in making the diagnosis of a coronary artery aneurysm is in the definition of a coronary artery aneurysm. The criteria for an aneu269
journal of the American Society of Echocardiography
270 Meyer
Figure 1 Various planes used to interrogate coronary arterial tree. A, Precordial short-axis view of great vessel illustrating plane used for artaining proximal right coronary artery. B, Change in short-axis plane to record left main artery. C, Higher position on chest with inferior inclination to obtain bifurcation of left main artery into left anterior descending and left circumflex arteries. D, Apical view used to obtain distal third of right coronary artery. E, Subcostal four-chamber view of plane used to record middle segment of right coronary artery in cross section. F, Plane used to record long-axis view of middle segment of right coronary artery by turning transducer about 90 degrees clockwise or counterclockwise. AO, Aorta; LA, left atrium; LCA, left coronary artery; LV, left ventricle; PA, pulmonary artery; RA, right atrium; RCA, right coronary artery; R V, right ventricle.
rysm depended on the criteria published in a 1985 report by the Research Committee on Kawasaki Disease of the Ministry of Health and Welfare in Japan. The report indicated that an aneurysm should be defined as an increase in the coronary internal diameter to more than l.S times the adjacent vessel diameter. In addition, it was also believed that an absolute internal diameter greater than 3 mm con-
stituted dilation of that coronary artery. However, normal values and a profile of coronary arteries in children were not available untill986, when Arjunan et al. 8 published values and characterized the profile for the proximal coronary artery caliber in normal children. In addition to the normal internal dimen· sions that ranged from 2 to 5 mm from infants to adolescents, it was found that the caliber of each
Volume 2 Number 4 July-August 1989
Echo in Kawasaki disease
271
Figure 2 Echocardiogram from 3-year-old patient with Kawasaki disease but no aneurysms. A, Left coronary artery (LCA) dimension at upper limit of normal. B, Right coronary artery (RCA) dimension at lower limit of normal. AO, Aorta; SAX, short-axis.
Figure 3 Echocardiogram from patient with Kawasaki disease demonstrating uniform caliber of left main branch bifurcating into left anterior descending (LAD) and circumflex (CFX) branches.
artery remained uniform from its origin to its distal extent. Aneurysms tend to narrow suddenly or taper gradually from a much larger size to a normal caliber. This feature has become important to recognize, since some patients have a perfectly normal dominant coronary artery system that is larger in caliber than its smaller contralateral coronary artery (Figure 2). With the advent of higher frequency transducers focused in the near and medium fields the imaging of coronary arteries, particularly in the young, has steadily improved. This technology and additional scanning planes have improved our ability to record with greater accuracy the anatomy of the coronary arteries (Figure 3), in particular the distal segments (Figures l, F, 4 and 5). Thus a diagnosis of aneurysm formation can be established and the fate of these aneurysms followed. Fortunately many of these lesions resolve, and the regression can be monitored by echocardiography in many instances. 9
Figure 4 Echogram showing dilated fusiform aneurysm of distal third segment of right coronary artery measuring only 0.41 em. LV, Left ventricle; RA, right atrium; R V, right ventricle.
Figure 5 Echogram from subcostal four-chamber view demonstrating saccular aneurysm in cross section of middle third of right coronary artery (arrow). LV, Left ventricle; RA, right atrium; R V, right ventricle.
272
Jo urnal of dte American Society of Echocardiography
Meyer
Figure 6 Echocardiograms from 6-week-old male patient with Kawasaki disease demonstrating development and progression of aneurysms in right and left coronary arteries. A, Small but irregular lumen of right coronary artery (arrows). B, Development of aneurysm of same artery (arrow). C, Development of thrombus in further enlarged right coronary artery (RCA, arrow) . D, Relatively normal left main and anterior descending arteries (arrows). E, Development of thrombus in large aneurysm of left anterior descending artery (arrow).
Not only has our ability to image the coronary arteries and aneurysms improved, but our ability to detect thrombus formation (Figure 6) and the subsequent coronary artery stenosis has also improved. In addition, the recanalization process of the obstructive thrombus after anticoagulant and enzyme
therapy can be monitored more accurately (Figure 7). The progression of the aneurysm to giant proportions (>8 mm) (Figure 8) dramatically increases the risk of thrombus formation, 10 although this 4-yearold patient has not developed a thrombus after l year.
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Echo in Kawasaki disease 273
Figure 8 Echogram of 4-year-old patient showing development of giant aneurysms of both proximal right coronary artery (PRCA, arrow) and left anterior descending (LAD) coronary artery. Left main artery (arrow) is normal.
Figure 7 Recanalization of both (A) left coronary artery (LCA, arrow) and (B) right coronary artery (RCA) thrombus (arrow) in same patient as Figure 6.
In our experience, the younger the infant (that is, younger than 6 months) at the time of diagnosis, the more likely the aneurysms will progress to giant size and develop thrombus (Figure 9). This 2-month-old boy later developed thrombus within 1 to 2 weeks of aneurysm formation. For this reason, these infants are examined almost daily during the first week or lO days and then weekly until 6 weeks after diagnosis to detect the appearance of aneurysms and or thrombi. Although no consensus has been reached as to the frequency of echocardiographic examinations, the protocol that we follow in our institution for those patients without evidence of aneurysms beyond 6 weeks is to obtain echocardiograms at 12 weeks, 9 months, 12 months, 18 months, 24 months, and then 1 to 2 years routinely after that. FUNCTIONAL ASSESSMENT
To date, single-gated Doppler (pulsed) and multigated Doppler (color flow) have added little to the direct evaluation of the coronary artery in these patients. The signals are varied and unreliable for the most part and very inconsistent. This is not totally
Figure 9 Development of giant aneurysm in right proximal coronary artery (arrows) of 2V2-month-old male patient who later developed a thrombus. Ao, Aorta.
unexpected, since the plane of interrogation of these arteries is for the most part perpendicular. In addition, the vessels are small, and flow characteristics do not lend themselves to meaningful information. Perhaps as time goes on these limitations will be overcome and greater functional data obtained. Conversely, Doppler clearly is helpful in assessing the presence ofvalvar regurgitation 11 . 13 (Figure 10). The aortic and tricuspid valves are affected in about 5% of patients. Most often the valvulitis is mild and resolves spontaneously. In addition to the valvar regurgitation, it also has been recognized that systolic and diastolic functional abnormalities exist in these patients. 14•15 This is not surprising, since these patients have microscopic changes in their coronary arteries and myocardium consistent with the inflammation associated with this disease. 16. 17 The issue of whether long-term left ventricular functional disability exists is not totally re-
Journal of the American Society of Echocardiography
274 Meyer
Doppler evidence of mitral valve regurgitation (arrows) that subsequently resolved in this 6-week-old male infant.
Figure 10
Pericardia! effusion during acute phase of illness in 6-month-old female patient.
Figure 11
solved. Nevertheless, evaluation of left ventricular dysfunction still depends primarily on M-mode and two-dimensional area shortening along with regional wall motion analysis. Most often the patients who have ventricular dysfunction also have effusions (Figure ll) that resolve with antiinflammatory treatment. The fate of the coronary arteries after resolution of the aneurysms is not known. One approach has been to evaluate the change in the caliber of the coronary artery between systole and diastole with angiographic techniques and densitometry. 18 Twodimensional directed M-mode measurements of the coronary arteries in patients with resolving aneurysms are being investigated, but data from such studies are not yet available. LIMITATIONS
Despite the advances in instrumentation and broadening of our understanding of the anatomy and var-
Selective coronary arteriograms of6-week-old male infant demonstrate near total occlusion of right (A) coronary arteries and left (B) circumflex artery, which was not detected by echocardiography. Patient later developed segmental wall motion abnormalities and myocardial infarction. Figure 12
ious planes of interrogation by echocardiography, limitations still exist. Many portions of the coronary arterial tree are still inaccessible to echocardiographic visualization. It is not possible to visualize many segments of the distal anterior descending, circumflex, or posterior descending branches. In addition, obstruction to flow from a thrombus is most difficult to assess. As alluded to by Pahl et al. 19 recently, total coronary occlusion by a thrombus may not be possible to detect echocardiographically. Either the area
Volume 2 Number4 July-August 1989
of stenosis is not visualized by echocardiography, or if it is visualized, it is not yet possible to determine whether there is occlusion to flow of that vessel. In addition, the occlusion may not produce symptoms. These two issues still plague the echocardiographer, but perhaps in time they may be overcome. Fortunately with rare exceptions, the proximal coronary arterial branches are involved whenever coronary artery aneurysms develop, regardless of the distal sites that are also involved. This is why we have been able to depend on echocardiography as a screening tool to detect the development of aneurysms; however, we still rely on selective coronary arteriography (Figure 12) to characterize the extent and nature of the aneurysms and their progression. SUMMARY
Since the early publications demonstrating the utility of echocardiography to image the coronary arteries in patients with Kawasaki disease, great strides have been made in instrumentation and imaging techniques, which permit better imaging capabilities and more accurate assessment of the arteries. Twodimensional imaging remains the keystone in the echocardiographer's armamentarium for evaluating this disease. The crucial element of the disease is the development of coronary artery aneurysms with subsequent thrombus formation and occlusion leading to myocardial ischemia and infarction. Echocardiography stil provides the simplest and most costeffective tool for evaluating the associated lesions and sequelae of this disease. However, when an aneurysm develops, selective angiography should be performed, although angiography in some cases has failed to show the extent of the aneurysm because of its limitation in visualizing the wall of the arteries. By the same token the converse is true; echocardiography may fail to show occlusion of flow in the arteries. Echocardiography and angiography must be used together prudently in these patients. As time goes on, advances in two-dimensional imaging, Doppler, and ideally tissue characterization will allow even greater accuracy in defining and characterizing the coronary arterial tree and myocardium of these patients.
REFERENCES l. Newburger JW, Takahashi M, Bums JC, et al. The treatment of Kawasaki syndrome with intravenous gamma globulin. N Eng! J Med 1986;315:345-7.
Echo in Kawasaki disease 275
2. Bierman FZ, Gersony WM. Kawasaki disease: clinical perspective. J Pediatr 1987;111:789-93. 3. Yoshikawa J, Yanagihara K, Owaki T, et al. Cross-sectional echocardiographic diagnosis of coronary artery aneurysms in patients with mucocutaneous lymph node syndrome. Circulation 1979;59:133-9. 4. Hiraishi S, Yashiro K, Kusano S. Noninvasive visualization of coronary arterial aneurysm in infants and young children with mucocutaneous lymph node syndrome with twodimensional echocardiography. Am J Cardiol1979;43: 122533. 5. Yoshida H, Maeda T, Funabashi T, et al. Subcostal twodimensional echocardiographic imaging of peripheral right coronary artery in Kawasaki disease. Circulation 1982; 65:956-65. 6. Satomi G, Nakamura K, Narai S, et al. Systematic visualization of coronary arteries by two-dimensional echocardiography in children and infants: evaluation in Kawasaki disease in coronary arteriovenous fistulas. Am Heart J 1984; 107:497505. 7. Capannari TE, Daniels SR, Meyer RA, et al. Specificity and predictive value of two-dimensional echocardiography in detecting coronary artery aneurysms in patients with Kawasaki disease. JAm Coil Cardiol 1986;7:355-60. 8. Arjunan K, Daniels SR, Meyer RA, et al. Coronary artery caliber in normal children and patients with Kawasaki disease but without aneurysms: an echocardiographic and angiographic study. JAm Coil Cardiol1986;8:1119-24. 9. Takahashi M, Mason W, Lewis AB. Regression of coronary artery aneurysms in patients with Kawasaki syndrome. Circulation 1987;75:387-94. 10. Tatara K, Kusakawa S. Long-term prognosis of giant aneurysm in Kawasaki disease: an angiographic study. J Pediatr 1987;111:705-10. 11. Nakano H, Ueda K, Saito A, et al. Dapper detection on tricuspid regurgitation following Kawasaki disease. Pediatr Radio! 1986;16:123-5. 12. Nakano H, Nojima K, Saito A, et al. High incidence of aortic regurgitation following Kawasaki disease. J Pediatr 1985; 107:59-63. 13. Gidding SS, Shulman ST, Ilbawi M, et al. Mucocutaneous lymph node syndrome (Kawasaki disease): delayed aortic and mitral insufficiency secondary to active valvulitis. J Am Coil Cardiol 1986;7:894-7. 14. Anderson TM, Meyer RA, Kaplan S. Long-term echocardiographic evaluation of cardiac size and function in patients with Kawasaki disease. Am Heart J 1985;110:107-15. 15. Nakano H, Ueda K, Saito A, et al. Left ventricular systolic function in children with coronary arterial lesion following Kawasaki disease. Heart Vessels 1985;1:89-93. 16. Yutani C, Go S, Karniya T, et al. Cardiac biopsy of Kawasaki disease. Arch Pathol Lab Med 1981;105:470-3. 17. Kohr RM. Progressive asymptomatic coronary artery disease as a late fatal sequela of Kawasaki disease. J Pediatr 1986;108:256-9. 18. Kurisu Y, Azurni T, Sugahara T, et al. Variation in coronary arterial dimension (distensible abnormality) after disappearing aneurysm in Kawasaki disease. Am Heart J 1987; 114:532-8. 19. Pahl E, John M, Clendaniel J, et al. The importance of angiography in assessment and follow-up of coronary abnormalities in Kawasaki disease [Abstract]. J Am Coil Cardia! 1988;11:29A.