Ten consecutive patients with a coronary artery fistula, aged 1 day to 4 years, were studied by two-dimensional echocardiography, pulsed Doppler ultrasound and color flow imaging. All patients underwent cardiac catheterization, and seven patients had surgical closure of the fistula. The origin, course and site of drainage of the coronary artery fistula were correctly identified prospectively by echocardiographic examination in all patients. Color flow imaging was particularly helpful in visualizing the site of drainage of the fistula. Diameters of the right and left coronary arteries at their origin and of the aortic root were measured from two-dimensional echocardiographic frames and compared with measurements obtained in normal children. The ratio of coronary artery diameter to aortic root diameter in normal children was 0.14 +/- 0.03 (mean +/- SD) for the right coronary artery and 0.17 +/- 0.03 for the left coronary artery. These normal ratios were greatly exceeded for coronary arteries feeding the fistula, and ranged from 0.68 to 0.84 for the right coronary artery and from 0.34 to 0.52 for the left coronary artery. All anatomic information needed for surgical treatment of coronary artery fistula was consistently obtained by echocardiography with color flow imaging. The fistula was closed from within the heart in five patients and by ligation from the epicardial surface in two patients. In these latter patients, intraoperative color flow imaging at the time of ligation proved to be extremely valuable in achieving complete closure.

At birth, pulmonary vasodilation occurs during rhythmic distension of the lungs and oxygenation. Inhibition of prostaglandin synthesis prevents pulmonary vasodilation during rhythmic distension of the lungs but not during oxygenation. Because endothelium-derived relaxing factor (EDRF) modulates pulmonary vascular tone at birth, at rest, and during hypoxia in older animals, we hypothesized that EDRF may modulate pulmonary vascular tone during oxygenation in fetal lambs. We studied the responses to N omega-nitro-L-arginine, a competitive inhibitor of EDRF synthesis, in nine near-term fetal lambs and to drug vehicle in six of these lambs and the subsequent responses to in utero ventilation with 95% O2 in these fetal lambs. In all fetal lambs, prostaglandin synthesis was prevented by meclofenamate. N omega-nitro-L-arginine increased pulmonary and systemic arterial pressures by 28% (P < 0.05) and 31% (P < 0.05), respectively, and decreased pulmonary blood flow by 83% (P < 0.05). In the controls, ventilation with 95% O2 increased pulmonary blood flow by 1,050% (P = 0.05) without changing pressures, thereby decreasing pulmonary vascular resistance by 88% (P = 0.05). During N omega-nitro-L-arginine infusion, ventilation with 95% O2 increased pulmonary blood flow by 162% (P = 0.05) and decreased pulmonary vascular resistance by 74% (P = 0.05). This suggests that EDRF may play an important role in modulating resting pulmonary vascular tone in fetal lambs and in the vasodilatory response to ventilation with O2 in utero.

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ABSTRACT. Prostaglandins (PG) are vasoactive factors involved in the regulation of pulmonary vascular resistance at birth. However, their physiologic importance is unclear. We hypothesized that PG are important regulators of pulmonary vascular resistance during static and rhythmic distension of the lungs. To test this hypothesis, we studied seven near-term fetal lambs treated with meclofenamate (a PG synthetase inhibitor) and six controls. The fetal lambs were instrumented on a long-term basis with vascular catheters to measure pulmonary arterial pressures, left atrial pressures, and pulmonary blood flow (radionuclidelabeled microsphere method). The fetal airway was intubated, and the ductus arteriosus wall was infiltrated with formalin to assure full patency during the study period. Pulmonary vascular resistance was calculated during baseline and during sequential in utero static distension of the fetal lungs, rhythmic distension, and ventilation with oxygenation. We found that during rhythmic distension, inhibition of PG synthesis abolished the 4-fold decrease in pulmonary vascular resistance seen in the control group. In contrast, during static distension, pulmonary vascular resistance did not change in either group, and during ventilation with oxygenation, pulmonary vascular resistance decreased 12-fold in both groups. We conclude that PG are important regulators of pulmonary vascular resistance during rhythmic distension but are not essential for the regulation of pulmonary vascular resistance during static distension or during ventilation with oxygenation. ( The sudden and dramatic decrease in pulmonary vascular resistance that occurs at birth is essential for the normal transition from fetal to neonatal circulation (1). This decrease in pulmonary vascular resistance is regulated by a complex and incompletely understood interplay between metabolic and mechanical factors the most important PG in the perinatal pulmonary circulation (3), is produced by the lungs of fetal goats and newborn lambs at the onset of mechanical ventilation (4) and at the onset of spontaneous breathing (5). However, inhibition of PG synthesis results in only moderate attenuation of the normal decrease in pulmonary vascular resistance at birth in acutely exteriorized full-term fetal goats (6) and in newborn lambs that were instrumented on a long-term basis (7). Therefore, the physiologic importance of PGs in the regulation of the perinatal pulmonary vascular resistance has been questioned (7).To put these observations in perspective, an understanding of the ventilatory and circulatory changes that occur simultaneously with the fall in pulmonary vascular resistance at birth is essential. These changes include rhythmic distension of the lungs, removal of fluid from the alveolar spaces, and changes in pH, arterial 0 2 tension, cardiac output, and systemic arterial pressures. All these changes, individually or in various combinations, can influence pulmonary vascular resistance. For instance, both rhythmic distension without oxygenation (...

We report on 2 sibs with cardiac and renal abnormalities. The first had hypoplastic left heart sequence and renal hypoplasia; the second had a complex congenital heart defect, renal agenesis, and cleft lip and palate. We suggest that these cases represent the first familial examples of the Holzgreve syndrome. As such, they demonstrate the phenotypic variability seen in sibs, and may serve to further delineate the syndrome.