Teruhiro Kawano

Intravascular ultrasound of coronary arteries in children. Assessment of the wall morphology and the lumen after Kawasaki disease.

BACKGROUND The long-term clinical issue in Kawasaki disease (KD) concerns the coronary artery lesion. Two-dimensional echocardiography and coronary angiography are routine examinations to evaluate the coronary lesions; however, these are not adequate to assess the wall morphology of the coronary artery (CA). Intravascular ultrasound imaging (IVUS), a new technology for the evaluation of the coronary artery lumen and wall morphology in vivo, was performed for patients after KD in their long-term follow-up, and we examined the new insights it gave. METHODS AND RESULTS IVUS was performed during cardiac catheterization in 20 subjects (10 patients after KD who still had coronary aneurysms or regressed coronary aneurysms, 2 after KD who had no coronary abnormal lesion, and 8 control patients with congenital heart disease and normal CA). We evaluated the wall structure at 10 to 15 sites of the CA in each patient. IVUS was performed with a commercially available ultrasound imaging catheter. Four sites of a CA aneurysm in KD demonstrated a markedly dilated lumen without thickened intima. One site of a CA aneurysm with calcification demonstrated an asymmetrical lumen by a dense echo with acoustic shadows. Twenty-two sites of a regressed CA aneurysm demonstrated a marked symmetrical or asymmetrical thickening of the intima with a dense echo, in which the size of the lumen was similar to that at a site near a regressed aneurysm. The sites of angiographically normal CA revealed normal structures and a thin intima in many instances. Nine of 28 sites in KD with a CA abnormal lesion, particularly near a coronary aneurysm or regressed aneurysm, demonstrated a mild thickening of the intima. All the 10 sites in KD without a CA abnormal lesion and all the 25 sites in patients with congenital heart disease with normal CA demonstrated a smooth intima. CONCLUSIONS This study demonstrated that the site of a regressed coronary aneurysm has a markedly thickened but smooth intima. The sites of angiographically normal CA after KD with or without a coronary lesion demonstrated normal IVUS findings in most instances but in some cases revealed a mild intimal thickening. IVUS is useful to evaluate the CA wall morphology and may contribute to the assessment of long-term CA sequelae and the possible development of arteriosclerotic changes in KD.

Three-dimensional helical computed tomographic angiography in neonates and infants with complex congenital heart disease

BACKGROUND For the clinical management of patients with complex congenital heart disease (CHD), accurate evaluation of their morphologic conditions is critical. Three-dimensional (3D) helical computed tomography (CT) angiography has been used to assess the vascular system in adult patients; the indication for complex CHD, especially in the neonatal period, has not yet been defined. Therefore the purposes of our study were to determine the quality and limitations of current 3D helical CT angiography for neonates and infants with complex CHD and to assess the clinical utility of this technique. METHODS AND RESULTS 3D helical CT angiography was performed in 17 patients with various types of complex CHD. Their median age was 41 days (range 3 days to 9 months), and mean body weight was 3.6 kg (range 2.2 to 8.5 kg). All 3D images were produced with the 3D reconstruction algorithm of shaded-surface display. Oral sedation was required in only 4 infants during the procedure. 3D helical CT angiography clearly demonstrated the shape and spatial relation of great arteries, proximal branch pulmonary arteries, anomalous pulmonary venous connections, the patent ductus arteriosus, and a shunt. The 3D information of extracardiac morphologic characteristics and 3D anatomic relation of each extracardiac structure were easily recognized by this imaging process. However, intracardiac structure could not be visualized because of blurred and/or unclear edges of the ventricular wall caused by respiratory movement. CONCLUSIONS 3D helical CT angiography represents an important additional diagnostic tool and may become an alternative method to angiography or other noninvasive techniques used in the evaluation of extracardiac anomalies in neonates and infants with complex CHD.

Evaluation of pulmonary artery histopathologic findings in congenital heart disease : an in vitro study using intravascular ultrasound imaging

OBJECTIVES This study aimed to 1) compare in vitro intravascular ultrasound images of human pulmonary arteries with corresponding histologic sections, and 2) correlate the relation between intravascular ultrasound findings and Heath-Edwards pathologic grade of pulmonary vascular changes. BACKGROUND The pathologic assessment of the pulmonary vascular bed is essential for diagnosis and management of congenital heart disease with pulmonary hypertension. METHODS We evaluated and compared intravascular ultrasound images with histologic findings at identical sites in 40 pulmonary artery segments from 17 autopsy studies: group 1 = 7 patients with pulmonary hypertension (Heath-Edwards grade I to V, 20 segments); group 2 = 10 patients without cardiopulmonary disease (20 segments). RESULTS In group 2, the pulmonary artery wall echo consisted of a single layer. In group 1, 1) all segments of pulmonary arteries from patients with pulmonary hypertension showed a three-layered appearance; 2) in patients with mild pulmonary hypertension (Heath-Edwards grades I and II), intravascular ultrasound demonstrated increased thickness of the echoluscent zone due to medial hypertrophy with no intimal reaction; 3) patients with severe pulmonary hypertension (Health-Edwards grade III or higher) had intravascular ultrasound findings of increased medial thickness and a bright inner layer from intimal hyperplasia; 4) percent wall thickness derived from intravascular ultrasound showed a significant correlation with that determined by histologic examination (r = 0.89, p = 0.0001, n = 20). CONCLUSIONS Changes observed with intravascular ultrasound imaging correlate well with histopathologic grade. Thus, intravascular ultrasound may have significant utility in the evaluation of pulmonary vascular morphology in patients with pulmonary hypertension.

Balloon dilatation of the pulmonary valve in a patient with pulmonary atresia and intact ventricular septum using a commercially available radiofrequency catheter.

Using a commercially available 5F deflectable radiofrequency catheter, we have succeeded in percutaneous valvotomy of an imperforate pulmonary valve and consecutive balloon dilatation in a baby with pulmonary atresia and intact ventricular septum. After the procedure, right ventricular systolic pressure fell from 125 mmHg to 65 mmHg, and right ventriculography demonstrated anterograde blood flow into the pulmonary arteries. There were no major complications. Doppler echocardiography at 1 year after the procedure demonstrated a pressure gradient across the pulmonary valve of 20 mmHg with mild pulmonary and tricuspid regurgitations.

Noninvasive evaluation of systolic pressures of pulmonary artery and right ventricle using contrast-enhanced doppler echocardiography: comparative study using sonicated albumin or glucose solution.

Evaluation of pulmonary arterial pressure is essential for the diagnosis and management of patients with congenital heart disease; it is usually done by cardiac catheterization. An alternative, noninvasive method may be clinically more useful. The purpose of this study was to assess the usefulness of the noninvasive determination of systolic pressure of the pulmonary artery and right ventricle by contrast-enhanced Doppler echocardiography. We selected 30 pediatric patients (28 with trivial or nonsignificant tricuspid regurgitant Doppler signals and 2 with significant tricuspid regurgitant Doppler signals) aged 2 months to 21 years. The flow velocity of tricuspid regurgitation was measured with continuous-wave Doppler of the right ventricular inflow view or left parasternal or apical four-chamber view before and after injection of two types of contrast medium (hand-agitated 5% glucose or sonicated albumin). The systolic pressure of the pulmonary artery was assessed as the estimated right ventricular systolic pressure (albumin method) minus the peak pressure gradient across the pulmonary valve (nonenhanced Doppler method). After injection of hand-agitated 5% glucose and sonicated albumin, trivial tricuspid regurgitation signals were enhanced in 25 of 28 patients (89%). In two patients, spectral envelopes were well defined enough to obtain the peak systolic velocity of the tricuspid regurgitation jet without contrast medium injection. Peak velocity was not altered by injection of contrast medium in these patients. There was significant correlation between the estimation by contrast-enhanced Doppler using hand-agitated 5% glucose and the cardiac catheterization measurement of the transtricuspid pressure gradient (r=0.88). The transtricuspid pressure gradients obtained by continuous-wave Doppler during sonicated albumin enhancement corresponded closely to those measured by cardiac catheterization (r=0.095). Pulmonary arterial and right ventricular systolic pressures measured by Doppler using sonicated albumin and those obtained by cardiac catheterization were highly correlated (right ventricle,r=0.96; pulmonary artery,r =0.95). In conclusion, this technique may be a valuable noninvasive method for determining accurate right ventricular and pulmonary arterial systolic pressures.

Fetal arrhythmias: Intrauterine diagnosis, treatment and prognosis

Fetal echocardiography can provide useful information for the evaluation of fetal arrhythmias. Between 1980 and 1993, 44 fetuses with arrhythmias were diagnosed in utero at 12 and 40 weeks of gestation in Kurume University Hospital. Fetal bradycardia, tachycardia and ectopic beats were revealed in 17, seven and 20 fetuses, respectively, and their clinical features and prognosis were evaluated. In the 17 fetuses with bradycardia, eight were associated with congenital heart defect, and six of these developed to fetal hydrops. Of the 17 fetuses, four died in utero, one was terminated, and six died after birth. The other six cases survived. Three of these had a pacemaker implanted after birth. In the seven fetuses with tachycardia, transplacental anti‐arrhythmic drugs were administered in five cases and conversion of the arrhythmia was achieved in four. None of the cases was associated with any congenital heart defect, and none died. Three infants had paroxysmal tachycardia postnatally. In the 20 fetuses with ectopic beats, arrhythmia was observed postnatally in 10, but all of these were resolved within 3 months after birth.