Hisashi Sugiyama

Endothelial function evaluated by flow-mediated dilatation in pediatric vascular disease

The endothelial function of children with and without vascular disease, consisting of 41 controls, 24 with Kawasaki disease (KD), and 46 with diabetes mellitus (DM), was examined. Age at examination ranged from 3 to 23 years (mean, 12.0 ± 4.7). The flow-mediated dilatation (FMD) and intima-media complex in the common carotid artery were measured. In controls age at examination was not associated with FMD or intima-media complex. FMD significantly decreased in children with KD and DM compared with the control group (control vs KD or DM: 11.7 ± 14.7 vs 3.0 ± 11.0 or 6.4 ± 8.5%, respectively; p < 0.05). However, there was no significant difference for intima-media complex among the groups. Furthermore, FMD in KD patients with coronary arterial aneurysm was lower than that in KD patients without aneurysm (-0.5 ± 9.2 vs 8.3 ± 9.1%, p < 0.05). In DM patients, FMD in the high HbA1c group (HbA1c = 7%) was lower than that in the normal HbA1c group (HbA1c < 7%) (4.8 ± 8.1 vs 11.4 ± 7.8%, p < 0.05). In conclusion, FMD detected endothelial impairment in children with KD or type 1 DM regardless of overt vascular complications, and FMD impairment occurs prior to intima-media complex thickening. By measuring both FMD and intima-media complex, useful information for predicting vascular complications may be obtained.

The Relation Between Right Ventricular Function and Left Ventricular Morphology in Hypoplastic Left Heart Syndrome: Angiographic and Pathological Studies

Abstract. Cases of hypoplastic left heart syndrome (HLHS) were studied angiographically in 18 patients and pathologically in 22 patients. They were divided into three subgroups according to the morphological features of the left heart: mitral atresia with aortic atresia (MA/AA), mitral stenosis with aortic atresia (MS/AA) and mitral stenosis with severe aortic stenosis (MS/AS). Patients with MS/AA had a significantly lower right ventricular end-diastolic volume index and more hypokinesis of the right ventricular posterior wall than those with MA/AA. MS/AA not only increased the thickness of the left ventricular posterior wall and interventricular septum but also increased endocardial thickness compared with MA/AA. Myocardial histology revealed more frequent abnormal findings such as myocardial necrosis, calcification and interstitial fibrosis in the mitral stenosis groups (i.e., MS/AA and MS/AS) than in MA/AA. Right ventricular function appeared to be greatly influenced by left heart structure. The presence of larger left ventricular muscle bulk and frequent myocardial damage seen in MS/AA seems disadvantageous to right ventricular end-diastolic volume and right ventricular wall motion.

Coronary arterial involvement and QT dispersion in Kawasaki disease

For the early detection of myocardial ischemia in patients with severe involvement of the coronary arteries after Kawasaki disease, a method with high sensitivity and low cost is desirable because these patients require frequent follow-up and diagnostic tests. For this purpose, electrocardiographic, echocardiographic, Holter, and stress testing or angiography are repeated. However, these tests have some limitations due to cost, convenience, or sensitivity. It is uncertain that increased QT dispersion would exactly indicate progression of myocardial ischemia after Kawasaki disease, but this is the first study to present that QT dispersion of > or = 60 ms had higher sensitivity for detection of severe involvement of coronary artery after Kawasaki disease. This study is limited due to the small number of patients; larger prospective studies are required to clarify the usefulness of QT dispersion analysis in detecting the progression of myocardial ischemia after Kawasaki disease.

Double-Orifice Mitral Valve Associated with Noncompaction of Left Ventricular Myocardium

Double-orifice mitral valve (DOMV) is a rare anomaly commonly associated with other congenital heart diseases. We present two patients with DOMV and noncompaction of the left ventricular myocardium (NLVM). Case 1 was a 5-year-old male diagnosed with dilated cardiomyopathy. His echocardiogram showed thin myocardium with dilatation at the basal of the left ventricle, thick noncompacted myocardium around the apex of the left ventricle, and DOMV (complete bridge type) with mild mitral regurgitation. Case 2 was an 11-year-old male diagnosed with complete atrioventricular block. His echocardiogram showed thick noncompacted myocardium with mild hypokinesis from the posterior to lateral wall and DOMV (complete bridge type) with mild mitral regurgitation. DOMV is commonly associated with congenital anomaly and always has an abnormal subvalvar apparatus. The mitral valve and its apparatus embryologically originate from the endomyocardium, which is thought to be the origin of noncompacted myocardium. We speculate that patients with DOMV may have NLVM.

The influence of morphological changes in amplatzer device on the atrial and aortic walls following transcatheter closure of atrial septal defects.

OBJECTIVE This study prospectively investigated morphological changes in Amplatzer Septal Occluder (ASO) over time and the influences of these changes on the atrial and aortic walls after atrial septal defect (ASD) closure. METHODS Between August 2005 and December 2007, 78 patients with ASD were treated with ASO devices and changes in the device shape, the device thickness, and relations of the discs to the atrial and aortic walls over time were evaluated by transesophageal echocardiography immediately and 3-12 months after deployment. RESULTS The maximum unstretched ASD diameter was 16.2 +/- 4.8 mm and the device diameter selected was 20.6 +/- 5.5 mm. At the time of last follow-up, the device thickness decreased by 17-33%, 6 of 26 devices with a flare shape on the aortic side developed a closed shape, and the relations of the discs to the anterior atrial and aortic walls changed from touching to intermittent compression in 14 of the 78 cases. In these 14 cases, the aortic rim was significantly smaller, the number of flared device shapes on the aortic side/the number of closed shapes immediately after deployment was significantly larger, and the maximum device thickness at the middle part was significantly more decreased than those in other cases. CONCLUSION As the device becomes thinner, loses its flexibility, and often changes from a flare-to-closed shape on the aortic side over time, the edges of ASO can start to compress the atrial and aortic walls. However, erosion was not recognized in these cases.

Responses of Plasma Norepinephrine and Heart Rate During Exercise in Patients After Fontan Operation and Patients with Residual Right Ventricular Outflow Tract Obstruction After Definitive Reconstruction

Abstract. To determine the exercise responses of patients with congenital heart disease, 20 patients—5 who had undergone a right ventricular outflow tract reconstruction (group R; age, 15 ± 2 years), eight who had undergone a Fontan operation (group F; age, 13 ± 2 years), and seven who had a history of Kawasaki disease (group C; age, 15 ± 1 years)—performed a treadmill exercise test. Patients of group R had a significant residual right ventricular outflow obstruction. Oxygen uptake (VO2), heart rate (HR), and plasma norepinephrine (NE) concentrations were measured at rest, during warm-up, at ventilatory threshold (VT), and at peak exercise. Exercise capacity was determined as a percentage of the predicted normal peak VO2 (%pVO2). The %pVO2 for groups R and F was 65 ± 10 and 56 ± 11, respectively. Peak HR for groups R and F was 171 ± 4 and 155 ± 5, which were lower than the HR for group C (p < 0.001). Although NE concentrations at rest, during warm-up, and at VT were significantly greater in groups R and F (p < 0.05), there were no significant differences in the NE concentrations at peak exercise. Peak HR correlated with %pVO2 (p < 0.001). The ratio of the increase in HR to NE from rest to VT was significantly lower in groups R and F than in group C (p < 0.001) and correlated with %pVO2 (r= 0.80; p < 0.001). These data suggest that sympathetic nervous activity in groups R and F is increased at rest and during mild to moderate exercises, and reduced sinus node sensitivity to NE may be partly responsible for the abnormal HR response during exercise of patients with uncorrected congenital heart disease.

Partial left ventriculectomy in an infant with dilated cardiomyopathy

being living autogenous tissue. Hence the potential for growth exists when the pulmonary autograft is used in the aortic position, and that is the reason the Ross operation is considered ideal for aortic valve replacements in infants and children. However, the potential for growth is lost when the pulmonary autograft is used in the mitral position because it has to be housed within the Dacron tube. On the other hand, inasmuch as the autograft is lying in the left atrium as a top hat, a partial or total preservation of the mitral valve apparatus is feasible, as was done in our patient. The autograft is a living autogenous tissue, fully flexible, and it cannot obstruct the left ventricular outflow tract because of its position inside the left atrium (Figs I and 2). The improved clinical condition of our patient, freedom from anticoagulation, absence of thromboembolism, and the maintained excellent performance of the pulmonary autograft in the mitral position 6 years later cautiously support this procedure as a viable alternative in specific clinical situations requiring replacement of the mitral valve. However, a larger The Journal of Thoracic and Cardiovascular Surgery March 1999

Cardiac and Haemodynamic Effects of Tacrolimus in the Halothane-Anaesthetized Dog

Tacrolimus (FK506) is a potent immunosuppressant widely used for the treatment of patients with solid organ transplantation and autoimmune diseases. The present study investigated the cardiac, haemodynamic and electrophysiological effects of tacrolimus. Tacrolimus in doses of 0.01 and 0.1 mg/kg was infused over 10 min. with a pause of 20 min. in halothane-anaesthetized dogs under monitoring of plasma drug concentrations (n = 5). Sub-therapeutic dose of 0.01 mg/kg hardly affected any of the cardiovascular variables except that it slightly delayed the repolarization. The clinically relevant dose of 0.1 mg/kg had negative chronotropic, inotropic and dromotropic effects, and lowered blood pressure by 70 +/- 12 mmHg, effects previously ascribed to Ca(2+) channel blocking action. Tacrolimus also delayed the repolarization process in a dose-dependent and reverse use-dependent manner with an increase in electrical vulnerability. The cardiovascular effects of tacrolimus were enhanced after the cessation of drug infusion, despite a decline in the plasma concentrations. In human embryonic kidney 293 cells, however, only supratherapeutic tacrolimus concentrations (>0.1 mumol/l) inhibited hERG K(+) current with a maximum inhibition of 28% at 10 mumol/l, indicating that other mechanisms might have also operated besides direct block of ionic channel function. The present study suggests that tacrolimus has negative chronotropic, inotropic and dromotropic effects in the heart, delays repolarization and lowers blood pressure. Moreover, the monitoring of the actual drug concentration may not necessarily reflect its effects on the cardiovascular system; thus, frequent monitoring of cardiovascular variables may be essential for tacrolimus-treated patients.

Gadolinium-based balloon angioplasty for pulmonary artery stenosis in an infant with a right isomerism

We report here the first described case of utilizing gadolinium‐based contrast material as the contrast agent during a catheter intervention treatment for pulmonary artery stenosis. The patient, a male infant with complex heart disease associated with a right isomerism, had a history of severe allergic reaction to iodine‐containing contrast agents. A combination of digital subtraction angiography and a gadolinium contrast agent, however, provided us with good‐quality images both before and after balloon angioplasty without any associated complications. This method should therefore be considered as an alternative angiographic procedure in children with a high risk of iodine‐related allergic complications. Catheter Cardiovasc Interv 2004;63:346–350.

Mid-term outcome after partial left ventriculectomy in pediatric patients.

From May 1998 to April 2000, we performed partial left ventriculectomy (PLV) in 3 pediatric patients with dilated cardiomyopathy (DCM). At the time of the surgery, their age ranged from eight months to three years. The first patient eventually had to receive a heart transplant, but all patients treated with PLV are alive to this day. Patient #1 was diagnosed with DCM at the age of five months, PLV was done on a semi-urgent basis at the age of eight months, when medium dose IV catecholamine therapy and mechanical ventilation were required. Fraction shortening (FS) as shown by echocardiography increased postoperatively from 8% to 15% along with marked clinical improvement. Her heart failure deteriorated three months after the surgery, and received a heart transplant in the United States when she was one year and two months old. Patient #2 developed severe heart failure two months after correction of a ventricular septal defect. Aggressive medical therapy failed to improve his condition, therefore PLV was done on an elective basis at the age of three years and five months. [The patient was initially hospitalized and underwent low dose catecholamine.] Postoperative course was well. The ventriculography one year after surgery showed an improvement of the left ventricular FS from 12% to 27% after PLV. He was still doing well at his most recent check up. Patient #3 was diagnosed with DCM as a neonate. PLV was done on an elective basis at the age of two years and five months. Her postoperative course was generally well. FS on echocardiography increased postoperatively from 10% to 25% along with marked clinical improvement. The timing of performing PLV is the most essential factor for postoperative course in our experiences. We consider that the best timing is when aggressive catecholamine infusion or mechanical ventilation is required. The mid-term outcome of PLV of pediatric patients is considered to be acceptable. We believe that PLV should be considered as a viable option for severe DCM patients.