Pulmonary arterial compliance in children with atrial and ventricular septal defect.

Previous studies have documented the normal values of pulmonary arterial compliance (Cp) in animals and adult humans. In the past, variations in Cp and its measurement in children with septal defects has been unknown. In the present study, we found the Windkessel model, which uses compliance and resistance as parameters, to be a useful tool in understanding Cp in pediatric patients. Calculations of Cp were based on the pulmonary arterial diastolic pressure waveform as an exponential function of time. First, Cp was estimated by studying pressure tracings of the main pulmonary artery (MPA) obtained from both routine cardiac catheterization and pressure measured by a catheter-tip manometer, which was performed during a catheterization study of seven children with various congenital heart diseases. Second, 124 children with atrial and ventricular septal defects aged between 45 days and 12 years were studied using the data obtained from routine catheterization. Hemodynamic data were used to calculate pulmonary vascular resistance (Rp), pulmonary arterial time constant (Tp) and Cp. A strong correlation (r = 0.954) was found in the Cp value estimated by data obtained from routine catheterization and from the catheter-tip manometer study. The present study shows an estimated mean (SEM) Cp in normal children of 1.53 (0.17) ml/mmHg per m2. The estimated mean (SEM) Cp was 1.91 (0.10) and 1.70 (0.11) ml/mmHg per m2 in children with atrial septal defect (ASD) and ventricular septal defect (VSD), respectively. It was found that Cp was significantly (P = 0.04) higher in female patients with a VSD. Also, a significantly low Cp (0.95 +/- 0.06 ml/mmHg per m2) was observed in patients with a VSD and pulmonary hypertension (VSDPH). In conclusion, Cp was calculated by the exponential decay portion of the MPA diastolic pressure waveform. A normal Cp value was observed in ASD and VSD patients and a significantly low Cp was observed in children with a VSDPH. Cp was higher in female VSD patients than in male VSD patients.

Forty year review of bacterial endocarditis in infants and children.

From 1950 through 1989 at Tokyo University's Department of Pediatrics, 25 children were treated for bacterial endocarditis. Twenty-two of these patients had previously been diagnosed as suffering from congenital heart disease. Twenty one of the 25 patients had positive blood cultures. Streptococcus viridans was the most common organism isolated, although the incidence of Streptococcus viridans infection has decreased in the last 20 years. In present series only a few post-surgical cases with congenital heart disease occurred. There were three deaths which all occurred prior to 1965.

[Relationship between deep body temperature and hemodynamics in pediatric patients with congenital heart disease].

Relationship of the abdomen-sole deep body temperature difference (DBT) to the hemodynamics was examined in patients with congenital heart disease. Hemodynamic data were obtained by routine cardiac catheter examination, and DBT was measured during the catheterization. Significant positive correlation was found between DBT and systemic-pulmonary flow ratio (Qp/Qs) (r = 0.85, p = 0.001). DBT was maintained below 2 C degrees in almost every patient when the Qp/Qs was less than 2, whereas DBT rose rapidly when the Qp/Qs was more than 2. Furthermore, systemic blood flow and arterial-venous oxygen difference ranged widely within the normal values when DBT was less than 2 C degrees. On the other hand, when DBT was more than 2 C degrees, systemic blood flow and arterial-venous oxygen difference tended to show fixed values which were around the normal upper or lower limits. This means that systemic circulation is marginally adapted when the Qp/Qs is more than 2. The measurement of deep body temperature difference is noninvasive, easy and useful as a circulatory monitor in pediatric patients with congenital heart disease.

Reconsideration of criteria for the Fontan operation. Influence of pulmonary artery size on postoperative hemodynamics of the Fontan operation.

BACKGROUND: The outcome of the Fontan operation largely depends on the selection of patients because this procedure is a physiological correction. Among the several selection criteria for the Fontan operation, the importance of adequate size of the pulmonary artery remains controversial. In this series, in order to clarify whether the pulmonary artery size is indispensable or not as one of the selection criteria for the Fontan operation, we considered the physiological meaning of pulmonary artery size and investigated how it influenced postoperative hemodynamics of the Fontan operation. METHODS AND RESULTS: In congenital heart disease of decreasing pulmonary blood flow, 40 patients were examined for this analysis. Pulmonary artery indexes (cross-sectional area of the right and left pulmonary arteries divided by body surface area) were measured as the expression of pulmonary artery size, and the relations of pulmonary artery index (PAI) to pulmonary vascular resistance (Rp) and compliance (Cp) were studied. There was no significant correlation between PAI and Rp, whereas a significant correlation was found between PAI and Cp (r = .71, P = .001). Furthermore, Cp influenced postoperative hemodynamics of the Fontan operation by affecting the peak central venous pressure (pCVP) and total impedance, which was the afterload to the ventricle. Impedance increased abruptly when PAI was < approximately 100 mm2/m2. CONCLUSIONS: The smaller pulmonary artery size causes more disadvantageous hemodynamics after the Fontan operation, with resultant effects of the rise in pCVP and the increase in afterload to the single ventricle.

Reconsideration of criteria for the Fontan operation. Influence of pulmonary artery size on postoperative hemodynamics of the Fontan operation.

BACKGROUND: The outcome of the Fontan operation largely depends on patient selection because this procedure is a physiological correction. Among the several selection criteria for the Fontan operation, the importance of adequate size of the pulmonary artery remains controversial. To clarify whether or not pulmonary artery size is indispensable as one of the selection criteria for the Fontan operation, we considered the physiological importance of pulmonary artery size and investigated how pulmonary artery size influenced postoperative hemodynamics of the Fontan operation. METHODS AND RESULTS: In congenital heart disease of decreasing pulmonary blood flow, 40 patients were examined for this analysis. Pulmonary artery indexes (cross-sectional area of the right and left pulmonary arteries divided by body surface area) were measured as the expression of pulmonary artery size, and the relations of pulmonary artery index (PAI) to pulmonary vascular resistance (Rp) and compliance (Cp) were studied. There was no significant correlation between PAI and Rp, whereas a significant correlation was found between PAI and Cp (r = .71, P = .001). Furthermore, Cp influenced postoperative hemodynamics of the Fontan operation by affecting peak central venous pressure and total impedance, which was the afterload to the ventricle. Impedance increased abruptly when PAI was less than approximately 100 mm2/m2. CONCLUSIONS: The smaller pulmonary artery size is hemodynamically disadvantageous after the Fontan operation, with resultant rise in peak control venous pressure and increased afterload to the single ventricle.

A new protocol for the perinatal management of patients with congenital diaphragmatic hernia with severe hypoplastic lungs and its clinical application.

It is prerequisite for the pre-operative management of patients with congenital diaphragmatic hernia (CDH) to avoid the factors that increase pulmonary vascular resistance, because such patients easily fall into the state of persistent fetal circulation (PFC). In this paper, a new protocol is proposed for the perinatal management of CDH patients to prevent the PFC which is facilitated by the enlargement of hernia and the deviation of mediastinum caused by spontaneous breathing just after birth. We also describe the usefulness of this protocol based on our experience in which we successfully treated a patient with CDH with severe hypoplastic lungs that were diagnosed antenatally by ultrasonographic examination. In treating the CDH patient with severe hypoplastic lungs, it is effective for the respiratory control and the prevention of PFC to administer morphine and pancuronium to the neonate through the umbilical vein before the resection of the umbilical cord. In the case of Cesarean section, in addition to the direct administration of morphine to the patient, administration of morphine to the patient's mother just before the delivery is more effective to prevent PFC, which can be easily induced by the initial resuscitation at birth.

Relationship between the pulmonary artery index and physiological properties of the pulmonary vascular bed.

BACKGROUND: To clarify the physiological significance of the pulmonary artery index (PAI), we examined the relationship between PAI and physiological properties of the pulmonary vascular bed. We also examined the limitations of PAI in practical use. METHODS AND RESULTS: We examined the relationships between PAI and pulmonary vascular resistance (Rp), pulmonary arterial compliance (Cp), and the time constant (RC) of pulmonary circulation in 50 patients with congenital heart disease with decreased pulmonary blood flow. PAI was significantly related to Cp and RC (r = 0.67, r = 0.63, respectively). These correlations became more significant when we excluded patients in whom the central pulmonary arteries were disproportionately dilatated in contrast to the peripheral pulmonary arteries (r = 0.80, r = 0.70, respectively). CONCLUSIONS: PAI reflects the state of the pulmonary vascular bed, especially when the peripheral arteries develop in proportion to the central pulmonary artery.

Use of the internal jugular vein approach in balloon dilatation angioplasty of pulmonary artery stenosis in children.

Generally, the approach used for balloon dilatation angioplasty for pulmonary artery stenosis in children is from the femoral vein. However, sometimes an alternative approach must be used because of femoral vein occlusion or some other reason. As reports have been limited about the results achieved using the internal jugular vein approach in pediatric interventional catheterization, we report on the internal jugular vein approach in balloon dilatation angioplasty of the pulmonary artery for pediatric patients and discuss the advantages of this approach. From 1991 through 1993 15 balloon dilatation angioplasties of the pulmonary artery using the internal jugular vein approach were performed in 14 pediatric patients, ranging in age from 4 months to 13 years. Based on this experience, we have evaluated this method from several viewpoints including the technique and possible complications. All procedures were performed without complications in all patients; and by inserting a 7 sheath it was even possible to perform balloon dilatation in a 4-month-old infant. A sheath as large as 9F could be inserted in other patients, and the double balloon method was used in seven patients. The Seldinger method was also available when the balloon catheter was too large to use with a sheath. For pediatric interventional cardiac catheterization, it was found that the internal jugular vein approach is relatively safe and reliable. Furthermore, catheterization of the pulmonary artery was easier with the internal jugular vein approach than with the femoral vein approach.

Acute heart failure and acute renal failure in Kawasaki disease.

Acute renal failure and acute heart failure are rare in Kawasaki disease. We experienced two patients with Kawasaki disease who presented acute renal failure and acute heart failure. These two patients gave us an important insight into the understanding of water balance and fluid therapy in Kawasaki disease. One patients showed acute prerenal failure due to fluid exudation from the intravascular to the extravascular space, and subsequent acute heart failure. The other patient showed acute heart failure caused by fluid infusion for the treatment of dehydration. It is suggested that acute renal failure could be caused by a fluid shift from the intravascular to the extravascular space in Kawasaki disease. It is also demonstrated that the reserve of cardiac function could be decreased in patients with Kawasaki disease due to myocarditis even with normal echocardiography and chest X-rays.

Ventricle works as a converting organ of atrial blood flow: physiological significance of mean ventricular pressure.

The roles and characteristics of the ventricle were examined using mean ventricular pressure (MVP) in ventricular-vascular association. One hundred and two patients with congenital heart diseases who had undergone cardiac catheterization were studied. They were divided into five groups: Group 1, atrial septal defect without pulmonary hypertension (PH); Group 2, ventricular septal defect (VSD) without PH; Group 3, VSD with PH; Group 4, pulmonary valvular stenosis; and Group 5 as a control group. Then, we examined the relationships between mean pulmonary artery pressure (MPAP) and mean right ventricular pressure (MRVP), and also between mean systemic arterial pressure (MSAP) and mean left ventricular pressure (MLVP) among the five groups. Furthermore, we defined new indicators to express the ease of blood flow through each ventricle. They were referred to as a conductance of the right ventricle (CDR) and a conductance of the left ventricle (CDL), respectively. Then they were compared among the five groups. The values of MPAP/MRVP and MSAP/MLVP were kept constant to be about 1.3 and 1.7, respectively. Furthermore, CDR was different between each group according to the property of the pulmonary vascular bed, whereas CDL took almost the same value among the five groups. The ventricle works as a converter of atrial blood flow so that it can achieve efficient blood transport.

New criteria for the radical repair of congenital heart disease with pulmonary hypertension. In order to avoid postoperative residual pulmonary hypertension.

In congenital heart disease (CHD) with pulmonary hypertension (PH) resulting from high pulmonary flow, we sometimes experience patients whose PH continues even after the normalization of flow following surgery. Preoperative identification of these patients is difficult even using direct hemodynamic measurements at cardiac catheterization. The purpose of this study is to interpret the state of the pulmonary vascular bed more precisely using a new theoretical approach and to present the criteria available for avoiding residual PH. During preoperative routine catheter examination in CHD patients with PH we applied the Windkessel model to the pulmonary circulation and calculated the diastolic time constant (Td) of the pulmonary circulation. Td of Group 1 (0.50 +/- 0.03 sec), 6 patients who manifested residual PH after surgery, was higher than that of group 2 (0.23 +/- 0.14 sec), 42 patients with normalized pulmonary artery pressure after surgery. Furthermore, the relationships between Td and pulmonary blood flow (Qp) or pulmonary to systemic flow ratio (Qp/Qs) were very sensitive for distinguishing between these two groups. Group 1 was located in the left-upper quadrant of the graph of Td vs Qp or Td vs Qp/Qs relationships, whereas group 2 was located in the right-lower quadrant. The relationships between Td and Qp or Qp/Qs were considered to reflect the pathological change in the pulmonary vasculature more precisely. As a consequence, they would be very useful in understanding the state of the pulmonary vascular bed and avoiding residual PH.

Comparison of the incidence of intracranial hemorrhage following conventional mechanical ventilation and high frequency oscillation in beagle puppies.

Controversy exists as to whether high frequency oscillation (HFO) increases the risk of intraventricular hemorrhage (IVH) compared with conventional mechanical ventilation (CMV). We compared the risk of intracranial hemorrhage after phenylephrine-induced hypertension, combined with a hypovolemic, hypotensive insult followed by rapid volume replacement in two groups of newborn beagle puppies (one group on a piston pump HFO and the other on CMV). A total of 12 beagle puppies (6 on HFO and 6 on CMV) survived the protocol. Arterial blood gas analysis and arterial blood pressures through the study were of the same magnitude in both groups. The length of time for which the puppies remained hypertensive and hypotensive also did not vary significantly between the groups. Intraventricular hemorrhages were observed in two of six CMV puppies and two of six HFO puppies. One animal in each group had a white matter hemorrhage. Subarachnoid hemorrhages were seen in 4 animals on CMV and 3 on HFO. This study indicated that HFO does not increase the risk of any kind of intracranial hemorrhage, including IVH, in beagle puppies.

Neurally mediated syncope complicated with paroxysmal atrial fibrillation.

Recently, it has come to be accepted that the result of the tilt test is specific to neurally mediated syncope (vasovagal syncope). Only rarely is a case of paroxysmal atrial fibrillation without any organic diseases in childhood reported. A case reported here of a 14-year-old boy with neurally mediated syncope; which was complicated by paroxysmal atrial fibrillation, and which was diagnosed by performing the tilt test. Atrial fibrillation can be induced by the extraordinary stimulation of the vagal nerve during syncope. In a child, neurally mediated syncope complicated with paroxysmal atrial fibrillation has not been previously reported.

Evaluation and comparison of the axis of the interventricular septum by two-dimensional echocardiography among the patients with congenital heart disease (ASD, VSD, PDA, PS, TOF) and the normal subjects.

A two-dimensional echocardiographic method was applied to determine the axis of interventricular septum (IVS) in the horizontal plane. This study comprised 19 subjects with ASD, 15 subjects with VSD(I), 20 subjects with VSD(II), 13 subjects with PDA, 16 subjects with PS, 15 subjects with TOF and 99 normal children. Parasternal left ventricular short axis view was taken, and the IVS was recorded by using the polaroid prints. The axis of the IVS in the horizontal plane was measured from the recorded polaroid prints. The value of the angularity of IVS (IVS-A) expressed as means +/- one standard deviation (mean +/- 1S.D.) is 52.0 +/- 13.7 degrees in ASD, 42.2 +/- 9.7 degrees in VSD(I), 43.7 +/- 9.1 degrees in VSD(II), 41.6 +/- 11.4 degrees in PDA, 38.6 +/- 10.9 degrees in PS, 61.0 +/- 8.5 degrees in TOF and 40.1 +/- 8.2 degrees in normal controls. There was no significant difference among VSD(I), VSD(II), PDA, PS and normal controls but a highly significant difference was noted in ASD and TOF as compared to other groups. The correlation coefficient of the IVS-A with (1) the Qp/Qs ratio, (2) the magnitude of shunt (%), (3) the right ventricular pressure and (4) the hematocrits were evaluated among the patient groups. The IVS-A of ASD and VSD(II) had a good correlation with the shunt flow (r = 0.921 and 0.88 respectively) and/or the Qp/Qs ratio (r = 0.782 and 0.955 respectively); while that of VSD(I), PDA, and PS had a good correlation with the right ventricular pressure (r = 0.956, 0.953, 0.842 respectively) and that of TOF was mostly concerned with the hematocrits (r = 0.911). Besides, the IVS-A in each severe CHD subgroup was significantly (p less than 0.005 or a better value) higher than the normal control group. Thus an alternative method was validated for evaluating the severity of congenital heart disease by using a noninvasive two-dimensional echocardiographic technique.

Two-dimensional pulsed Doppler echocardiographic technique for estimating pulmonary to systemic blood flow ratio in children with atrial septal defect and patent ductus arteriosus.

A two-dimensional pulsed Doppler echocardiographic method was evaluated for quantifying the pulmonary (Qp) to systemic (Qs) blood flow ratio. Twenty six patients were studied, 15 with atrial septal defect (ASD) and 11 with patent ductus arteriosus (PDA). An apical four-chamber view was used to measure the maximal Doppler flow velocities in the right and left ventricular inflow regions (RVIR and LVIR) and the maximal diameters of the tricuspid and mitral anuli at diastole. The two-dimensional pulsed Doppler pulmonary to systemic blood flow ratio (Qp/Qs) estimation involved calculating the area of the Doppler flow velocity signal along the time scale multiplied by the diameter of either the tricuspid or mitral anulus as measured on the apical four-chamber view. In ASD patients, Qp was measured at RVIR and Qs at LVIR. In PDA patients, Qp was calculated at LVIR and Qs at RVIR. Twenty-six healthy children comprised the control group. The areas of the Doppler flow velocity signals along the time scales of RVIR and LVIR were also quantified and the diameters of the tricuspid and mitral anuli were measured. In the control group, the linear correlation of the trans-mitral M(d)*M(a) to trans-tricuspid T(d)*T(a) value was r = 0.909, n = 26. The correlations between Doppler Qp/Qs ratio estimates and those obtained at cardiac catheterization were r = 0.902, n = 15 in ASD and r = 0.967, n = 11 in PDA. These results suggest a clinical application of this Doppler echocardiographic method in the noninvasive estimation of the cardiac shunt in ASD and PDA.