Transformation of coronary artery aneurysm to obstructive lesion and the role of collateral vessels in myocardial perfusion in patients with Kawasaki disease.

OBJECTIVES: The aim of this study was to examine the transformation of coronary artery aneurysms to obstructive lesions and to assess the role of collateral vessels in patients with Kawasaki disease. BACKGROUND: Coronary artery aneurysms, especially giant aneurysms, are known to become obstructive lesions in patients with Kawasaki disease. However, the process of transformation is not yet clear. METHODS: Thirty patients (average age 9.9 years) with obstructive lesions secondary to Kawasaki disease underwent repeated coronary artery angiography and thallium myocardial scintigraphy over a mean period of 7.7 years after the acute onset of Kawasaki disease. RESULTS: In the 27 patients who were enrolled in the acute phase of the disease because of coronary artery aneurysms, the later transformation to obstructive lesions was not significantly different between the 61 large and 6 medium-sized aneurysms. Obstructive transformation of aneurysms was more rapid in the right than in the left coronary artery (p < 0.001). From the last coronary angiogram obtained, the obstructive lesions were classified as localized stenosis > 90% in 10 vessels, occlusions in 6 vessels and segmental stenosis in 26 vessels. Both localized and segmental stenosis occurred significantly more often in the left anterior descending and the right coronary artery than in other vessels (p < 0.05). The incidence of collateral vessels was significantly correlated with a younger age at onset of Kawasaki disease, especially in patients with segmental stenosis (p < 0.001). Collateral vessels did not develop in the presence of localized stenosis regardless of the occurrence of myocardial ischemia. All occluded vessels had collateral development regardless of the presence of myocardial infarction. CONCLUSIONS: The treatment of localized stenosis may play an important role in preventing myocardial infarction in the chronic phase of Kawasaki disease.

Reversible left ventricular dysfunction with coronary stenotic or obstructive lesions in Kawasaki disease.

BACKGROUND: Few studies have been reported on the prognosis or reversibility of ischemic myocardial lesions in Kawasaki disease. In this study, the pathophysiologic causes of reversible left ventricular dysfunction were evaluated in seven children with severe stenotic coronary lesions caused by Kawasaki disease. METHODS: The clinical process and the changes of coronary lesions in the repeated angiography were retrospectively evaluated in seven children. The ages of the seven patients (six boys and one girl) ranged from 7 to 15 years (mean, 10.4 +/- 2.6 y); the duration from the onset of Kawasaki disease to the last angiographic study ranged from 6 to 15 years (mean, 9.6 +/- 3.0 y). RESULTS: During the acute stage, an acute myocardial infarction was detected clinically in two patients, transient ST depression in two, and deep Q waves without any symptoms in the remaining three patients. In the first angiographic study (2 mo to 6 y after the onset of Kawasaki disease), significant left ventricular dysfunction was observed in the posterior or inferior wall in all patients. In the right coronary arteries, giant aneurysms (> or = 8 mm in diameter) were angiographically detected in two patients, localized stenosis (> or = 95%) in one, and recanalization in four. In a recent angiographic study, the left ventricular dysfunction had normalized in all seven patients. Recanalization was observed, even in two patients with giant aneurysms and in one with localized stenosis. Collateral circulation was detected in five patients in this study. Abnormal deep Q waves on ECG were detected in only one patient, and no abnormal findings on ECG were seen in the remaining six. Upon 201TI myocardial scintigraphy, no reduction of 201TI uptake was observed in any of the seven patients at the site of the abnormal wall motion on the first angiography. CONCLUSIONS: The regional left ventricular dysfunction in the seven patients may have been induced by severe acute ischemia due to a transient right coronary obstruction or by severe chronic ischemia due to coronary lesions. Eventually, left ventricular wall motion normalized after an improvement in the blood flow supply as a result of early recanalization and development of collateral circulation.

Assessment of effects of intravenous dipyridamole on regional myocardial perfusion in children with Kawasaki disease without angiographic evidence of coronary stenosis using positron emission tomography and H2(15)O.

BACKGROUND: Positron emission tomography and H2(15)O were used to characterize regional myocardial blood flow and distribution at rest and in response to dipyridamole in children with Kawasaki disease but without angiographic evidence of coronary stenosis. METHOD: Patients were classified into two groups on the basis of the results of selective coronary angiography: subjects in group I had normal coronary angiograms (n = 4): subjects in group II had aneurysms (n = 5). RESULTS: Myocardial perfusion, assessed with H2(15)O, was homogeneous over all regions at rest and at peak flow in groups I and II. Dipyridamole infusion significantly reduced myocardial perfusion reserve in group II (average 3.56 +/- 1.03 fold versus 5.06 +/- 1.37 fold in group I, P < 0.001). CONCLUSION: Our results suggest that aneurysms associated with Kawasaki disease may reduce myocardial reserve. Non-invasive quantitative assessment of myocardial blood flow with positron emission tomography and H2(15)O was useful in assessing the functional capacity of coronary artery lesions and the extent of myocardial damage in children with Kawasaki disease.

[Exercise and dipyridamole-loading in evaluation of ischemic coronary lesion and coronary reserve in children with Kawasaki disease].

In order to compare the clinical effects of exercise-loading and intravenous dipyridamole-loading tests in evaluating ischemic coronary lesion and coronary reserve, we evaluated changes in ECG, 201-Tl scintigraphy, coronary flow and myocardial metabolism in 10 patients with Kawasaki disease (age range: 7-16 years). Although both loading tests affect coronary hemodynamics and myocardial metabolism by different mechanisms, both were equally effective in detecting ischemic coronary lesion and reduced coronary reserve. On the other hand, when considered on the basis of clinical examination methods used, the dipyridamole-loading test was more effective for evaluating clinical symptoms and ECG, while exercise-loading was more effective for evaluating 201Tl scintigraphy and supply-demand balance. These results suggest that, in the evaluation of ischemic coronary lesion, assessment of clinical effects by a combination of several examination methods is required.

Coronary arterial flow-velocity dynamics in children with angiographically normal coronary arteries.

BACKGROUND: There have been few reports about coronary hemodynamics in children during the process of growth. In the present study, to assess the characteristics of coronary flow dynamics in children, we examined the phasic coronary flow-velocity (CFV) patterns at rest and during peak hyperemic responses in children with angiographically normal coronary arteries. METHODS AND RESULTS: Spectral Doppler phasic coronary flow velocity was recorded with a 0.018-in intracoronary Doppler guidewire at rest and during peak responses after intracoronary bolus injection of ATP in 30 patients with Kawasaki's disease (age, 8.2 +/- 5.1 years; 24 boys and 6 girls) without angiographic coronary lesions. Average peak velocity (APV), maximum peak velocity (MPV), and diastolic-to-systolic velocity ratio (DSVR) were evaluated in the left anterior descending coronary artery (LAD), left circumflex artery (LCx), and right coronary artery (RCA). Coronary vasodilator reserve (coronary flow reserve [CFR]) was calculated as the ratio of ATP-induced hyperemic to baseline APV. Flow-velocity parameters in RCA were significantly lower than those in the LAD and LCx in both proximal and distal portions. Although the distal LCx had significantly lower values of APV and MPV than did the proximal LCx, there was no significant difference between the proximal and distal portions of the LAD and RCA for APV and MPV. All three coronary vessels showed a diastolic dominant flow pattern in each segment. This coronary flow pattern was less marked in the RCA than in the LCA. All three coronary vessels showed a significant increase in APV and a significantly decrease in DSVR after ATP administration. CFR was significantly lower in the LCx than in the LAD or RCA (P < .01: 1.93 +/- 0.34 in LCx versus 2.32 +/- 0.42 in LAD and 2.37 +/- 0.44 in RCA). From the view of aging, it was revealed that APV values in three vessels were higher in the younger group than in the older group. CFR values in the LAD and LCx were significantly lower in the younger group than in the older group (P < .001 in LAD: 2.01 +/- 0.28 in the younger versus 2.53 +/- 0.37 in the older; P < .01 in LCx: 1.61 +/- 0.15 in the younger versus 2.06 +/- 0.31 in the older). In addition, intracoronary injection of ATP did not increase the absolute angiographic coronary luminal diameter. CONCLUSIONS: With the use of an intracoronary Doppler guidewire, we demonstrated that there are some characteristic findings in CFV dynamics in childhood. These physiological characteristics in CFV dynamics that occur with aging and occur in each vessel must be taken into consideration in the study of the coronary circulation in children.

[Color Doppler flow imaging of two newborns with subclavian steal phenomenon of the interrupted aortic arch (type B)].

Subclavian steal may occur in newborns with interrupted aortic arch (type B) as a result of collateral circulation. Color Doppler flow imaging could detect reversed blood flow images in the diastolic phase at the subclavian artery of two neonates with interrupted aortic arch (type B), indicating subclavian steal phenomenon at the left subclavian artery via the left vertebral artery. The diagnoses were confirmed by retrograde angiography from the radial artery.

[Effects of isosorbide dinitrate on coronary and systemic circulation in children: comparison with dipyridamole].

The effects of isosorbide dinitrate (ISDN) on the coronary and systemic circulation were evaluated in comparison with the effects of dipyridamole (DP) in 8 children with histories of Kawasaki disease and angiographically normal coronary arteries. ISDN (100 micrograms/kg) was administered as an intracoronary injection. DP was administered intravenously at the rate of 0.56 mg/kg for 4 min. In the coronary circulation, DP induced a significant reduction of the afterload, resulting in an increase in cardiac output. However, the pulmonary artery pressure, pulmonary capillary wedge pressure and left ventricular end-diastolic pressure, which are related to the preload, were significantly reduced one min after the ISDN injection. The systolic blood pressure was reduced, while the heart rate was increased. The cardiac output, pressure-rate product or systemic vascular resistance showed no significant change. The systolic work index, however, was significantly reduced. In the coronary circulation, DP significantly increased the coronary sinus blood flow due to dilatation of the resistant vessels. However, ISDN significantly dilated the conductant vessels by 4.0 to 12.9% in diameter. There was, however, no change in the coronary blood flow, coronary perfusion pressure nor coronary vascular resistance. The grade of dilatation of the coronary vessels caused by ISDN was lower in children than in adults.