Transcatheter occlusion of large pulmonary arteriovenous fistula.

We describe the compound transcatheter occlusion of a large and symptomatic pulmonary arteriovenous malformation in a 58-yr-old man. Pre- and postintervention clinical and laboratory data support the impression of an excellent outcome.

Significant pulmonary valve incompetence following oversize balloon pulmonary valveplasty in small infants: A long-term follow-up study.

Oversized dilatation balloons are recommended for relief of valvar pulmonic stenosis in infants and children during cardiac catheterization. Little information exists about the long-term outcome of this practice. Six of 107 consecutive patients undergoing balloon pulmonary valveplasty developed increasing pulmonary valve incompetence during follow-up periods of 0.5-10 years (mean, 7.2 years). Secondary right ventricular dilatation prompted insertion of a bioprosthetic pulmonary valve in one patient 6.8 years after intervention; valve replacement is pending in two additional patients, 4.3 and 10 years after intervention, respectively; and the three remaining subjects are thought likely to require valve replacement during childhood. The six reported subjects differ from the pulmonary valveplasty group as a whole in that they are younger (median age, 3 days vs. 11 months), had a higher degree of obstruction (right/left ventricular systolic pressure ratio prior to valveplasty 1.28 vs. 0.92), and underwent dilatation with relatively oversized balloons (balloon diameter to pulmonary valve annulus ratio 1.44 vs. 1.08). The balloon diameter to valve annulus ratio did not exceed 1.5 in any subject. Caution is advised in the use of oversized dilatation balloons in neonates or young infants with severe or critical pulmonic stenosis. Long-term consequences of substantial pulmonary valve incompetence outweigh, in our opinion, the limited gradient relief achieved with smaller balloons, sometimes requiring a second dilatation of the valve at an older age and larger size. Cathet. Cardiovasc. Intervent. 48:61-65, 1999.

Vessel-sparing technique for coil occlusion of the very small patent ductus arteriosus.

A technique is described for coil occlusion of the small patent ductus arteriosus through a 4 French arterial catheter. The need for a 5 French sheath and catheter to stabilize the 3 French size delivery catheter system is obviated. The method is proposed as a way to minimize arterial vascular injury in the small patient undergoing transcatheter occlusion of the small ductus.

Great vein and right atrial thrombosis in critically ill infants and children with central venous lines.

We performed a retrospective review of echocardiographic data files of infants and children hospitalized in the Newborn and Pediatric Intensive Care Units. Echocardiograms were examined to detect the presence and evolution of great vein and right atrial thrombosis in patients with central venous lines. Thirty-seven patients were identified over a five-year period. Echocardiograms were performed, not routinely, but in response to specific indications including catheter malfunction, thrombocytopenia, persistent chylothorax, bacterial or fungal sepsis, and superior vena cava syndrome. Fifteen of 37 patients died, 13 of them during the hospitalization in which the thrombus was discovered. Thrombolytic agents and surgery were used to treat selected patients, with mixed results. Two of the 22 survivors have significant disability related to the thrombus or complications arising from it. We conclude that great vein and/or right atrial thrombosis is a common complication of central venous catheterization in small infants and children; moreover, the morbidity and mortality relating to this complication is substantial.

Hemodynamic effects of ketamine in children undergoing cardiac catheterization.

Ketamine is used to supplement sedation during cardiac catheterization. We studied ketamine-induced circulatory changes in 28 acyanotic children (18 of whom had left-to-right shunts), aged 4-161 months (mean, 33 months). Oxygen consumption (VO2) was measured continuously. In the 18 patients with shunts, the pulmonary to systemic flow ratio fell slightly (2.3 +/- 1.1 to 1.8 +/- 0.4, p less than 0.05). In all patients, the ratio of pulmonary (PVR) to systemic vascular resistance (SVR) rose from 0.16 +/- 0.09 to 0.28 +/- 0.21, p less than 0.001. Ketamine increases VO2, heart rate, cardiac output, and pulmonary arterial pressure (PAP). The rise in PAP is more consistent than the rise in PVR; resistance changes were greatest in patients with elevated resting PVR (r = 0.54). Caution should be used in administering ketamine to selected subjects; moreover, ketamine can confuse interpretation of cardiac catheterization data, especially if VO2 is assumed and not measured.

Medical management of three asymptomatic infants with severe valvar aortic stenosis.

We report on the clinical course and serial hemodynamic studies of three patients with severe valvar aortic stenosis diagnosed in the neonatal period. None of the children were symptomatic in the first year of life. In each case, a conservative initial management approach was adopted. Between the time of initial study (mean age, 1.8 months) and the follow-up at 12-27 months of age (mean, 14.3 months), mean left ventricular systolic pressure decreased from 151 to 125 mmHg, the mean peak systolic pressure gradient across the aortic valve decreased from 61 to 33 mmHg, and the mean calculated aortic valve area index increased from 0.24 to 0.60 cm2/m2. One patient was operated on for symptoms that appeared at 14 months of age. The patient followed longest is now 5 years old, is growing well, has a normal electrocardiogram and an echo-predicted left ventricular systolic pressure of 128 mmHg. This experience suggests that not all asymptomatic neonates with severe valvar aortic stenosis require surgical intervention early in life. In some, the aortic valve orifice may increase in size with somatic growth and obviate the need for surgery in infancy or early childhood.

Effect of resistive training on plasma lipid and lipoprotein levels in male adolescents.

We studied fourteen 14 to 17-year old male adolescents before and after a 9-week resistive exercise program and compared the changes in lipid and lipoprotein profiles with those in 14 non-exercising control subjects. Studies included determination of weight, body mass index (weight for height2), percent body fat, blood pressure and resting heart rate, maximum heart rate and maximum oxygen consumption, and plasma lipids and lipoproteins. No significant differences were present between the two groups before training except that percent body fat was lower in the control subjects. After training, low-density lipoprotein cholesterol in the exercising subjects decreased from 120 +/- 15 to 95 +/- 13 mg/dL (P less than 0.001), high-density lipoprotein cholesterol increased from 35 +/- 12 to 45 +/- 8 mg/dL (P less than 0.01), and high-density lipoprotein cholesterol/total cholesterol ratio increased from 0.2 +/- 0.06 to 0.27 +/- 0.05 (P less than 0.001). Control subjects showed a significant increase in weight (P less than 0.01) and body mass index (P less than 0.01) and a decrease in maximum heart rate (P less than 0.01) at the end of the 9 weeks. Adjustment for body mass index resulted in no alteration in the favorable response of the lipoprotein profile. No change occurred in body composition or maximum oxygen consumption with training. These findings indicate that resistive training is associated with a favorable alteration in the lipoprotein profile in adolescent males.

Noninvasive assessment of cardiopulmonary function in critically ill infants and children.

Echocardiography and Doppler echocardiography allow for the accurate noninvasive assessment of cardiac structure and function. Two-dimensional echocardiography accurately demonstrates both normal and abnormal intracardiac and great vessel anatomy and assists in differentiating cardiac from noncardiac causes of respiratory distress. M-mode echocardiography allows for documentation of cardiac chamber size and left ventricular function. Doppler echocardiography is used to measure cardiac output, assess AV and semilunar valve function, detect abnormal flow patterns within the heart and great vessels, and assist in the assessment of pulmonary artery pressures. This article discusses the uses of all these modalities as they apply to the critically ill infant and child.

Cardiac hypertrophy associated with ACTH therapy for childhood seizure disorder.

Hypertrophic cardiomyopathy is a newly recognized, potentially fatal complication of ACTH therapy. We report the clinical, echocardiographic, and pathologic findings of an infant who was treated with ACTH for seizure disorder and subsequently developed severe systemic hypertension. Echocardiography revealed marked cardiac hypertrophy with disproportionate septal hypertrophy. Decreasing the dose of ACTH reduced the systemic blood pressure, but the cardiac hypertrophy progressed and the child subsequently died. Children who develop hypertension during ACTH therapy should be considered at risk for hypertrophic cardiomyopathy and should undergo routine echocardiographic evaluation.

Systemic oxygen transport in patients with congenital heart disease.

The physiology of oxygen delivery was studied in 118 stable patients from 3 months to 20 years old with congenital heart disease. During cardiac catheterization, oxygen consumption (VO2), arterial and venous blood gases and oxygen saturations (range 41% to 98%), hemoglobin concentration, diphosphoglycerate (2,3-DPG), and P50 levels were measured, and then cardiac output, systemic oxygen transport (SOT), arterial and venous oxygen contents, and the VO2/SOT ratio (fractional O2 extraction) were calculated. P50 averaged 31 mm Hg, compared with 27 mm Hg in 10 control children (p less than .01). The composite O2-hemoglobin dissociation curve in vivo was broad: Po2 varied from 37 to 65 mm Hg at 80% saturation. P50, 2,3-DPG, hemoglobin concentrations, and O2 saturation varied widely and inconsistently with Po2 and arterial and venous O2 content, but resulted in clustering of the arterial oxygen content near 165 +/- 23 (SD) ml/liter over a wide range of Po2 and hemoglobin concentrations. SOT varied in direct relation with flow (r = .82, p less than .001), but not with oxygen content, Po2, or P50. VO2 varied widely at normal or high levels of SOT, but decreased linearly at SOT levels below 400 ml/min/m2. Oxygen extraction varied inversely with venous O2 content, rising to about 50% and plateauing below venous contents of 100 ml/liter. O2 extraction did not correlate with Po2, arterial O2 content, or P50. These data suggest that: O2 saturation cannot be predicted or calculated accurately from measured Po2, but must be measured directly, 2,3-DPG, hemoglobin concentration, and P50 fluctuate to stabilize arterial oxygen content, SOT is determined primarily by cardiac output in subjects who are adapted chronically, O2 extraction rises, due to a fall in venous O2 content, to maintain VO2 as transport falls, below a critical level of SOT, O2 extraction ceases to rise and VO2 falls with further reduction in transport.

Long-term follow-up of bronchopulmonary dysplasia.

We observed 10 children with bronchopulmonary dysplasia, evaluated initially by cardiac catheterization (mean age 18 months), for an average of 4.4 years. Age at last evaluation averaged 5.8 years; subjects reside in and around Albuquerque, N.M. (altitude 5000 ft). At initial cardiac catheterization, mean pulmonary artery pressure was 40 mm Hg, pulmonary vascular resistance index 8.9 units, and intrapulmonary shunt fraction was high; pulmonary wedge angiograms were normal. Over the period of follow-up the group has done poorly. Four of the 10 continue to receive home oxygen therapy, but none requires inotropic or diuretic therapy; four children have marked developmental or motor delays. Nine of 10 patients have abnormalities of respiratory function on spirometric testing. Four patients underwent recatheterization because of clinical indications; two had large atrial level left-to-right shunts not found on initial study. Reductions in pulmonary artery pressure (55 to 37 mm Hg) and pulmonary vascular resistance (11.9 to 7.8 units) occurred between the two studies in these four patients (average study interval 4.0 years); the still elevated levels of pressure and resistance fell further in response to 40% O2 administration. Pulmonary wedge angiograms were abnormal in each restudied patient. Although not uniformly bleak, the long-term outlook for children with severe bronchopulmonary dysplasia is diverse and guarded.

Hypertrophic cardiomyopathy in the adolescent.

Hypertrophic cardiomyopathy is the more accurate term for the condition also known as idiopathic hypertrophic subaortic stenosis, asymmetric septal hypertrophy or hypertrophic obstructive cardiomyopathy. Although an uncommon condition in the adolescent, its importance lies in the fact that it is hereditary, sometimes difficult to diagnose clinically, and may be associated with sudden death - especially during or after exertion. All patients with a systolic murmur at the left sternal border should be made to stand, squat and perform a Valsalva maneuver while being auscultated. Since hypertrophic cardiomyopathy is associated with a dynamic intraventricular gradient, the murmur will change in character and intensity during these maneuvers. An electrocardiogram and echocardiogram is indicated if there is any suspicion of the diagnosis. Patients with hypertrophic cardiomyopathy should be prohibited from participating in competitive sports or performing strenuous activities even in the absence of a significant intracavitary gradient. They should be placed on high-dose beta-blockers and followed closely. Follow-up should include the use of Holter monitoring to exclude the presence of arrhythmias. Supraventricular or ventricular arrhythmias should be treated aggressively since they may be associated with sudden death. Family members or first-degree relatives should be screened by echocardiography for the condition and the patient informed of the genetic nature of the disease. The condition needs to be differentiated from the 'athlete's heart' which may present with a murmur and electrocardiographic and echocardiographic evidence of left ventricular hypertrophy, since the latter condition is considered physiologic and not an indication to discontinue an athlete's activities.

Cardiac dysfunction during status epilepticus in the neonatal pig.

Cardiovascular complications frequently occur during status epilepticus. To determine the changes in systemic and pulmonary arterial pressure, cardi output, and left ventricular contractility during seizures, 1-week-old pigs were intubated, paralyzed, mechanicall entilated, and catheterized with a Swan-Ganz catheter. Seizures were induced with intravenous bicuculline. Early changes consisted of significant systemic and pulmonary arterial hypertension. After 2 hours of seizures, the animals developed progressive systemic hypotension and decreased cardiac output. M-mode echocardiography disclosed a decrease in left ventricular contractility. Cardiac tissue frozen in situ showed a significant increase in lactate and reductions in glucose, triglyceride, and adenosine triphosphate levels. Prolonged seizures in the neonatal pig result in cardiac dysfunction, which may play a role in the development of epileptic brain damage.

Acute myocardial effects of chloramphenicol in newborn pigs: a possible insight into the gray baby syndrome.

Mechanical function and mitochondrial respiration were observed in newborn pig hearts in the presence of chloramphenicol. Isolated perfused hearts exposed to chloramphenicol (25, 50, or 100 micrograms/ml) demonstrated acute reductions in pressure development and cardiac output accompanied by elevated left atrial filling pressure. The effects of chloramphenicol and chloramphenicol succinate (25, 50, 100, or 200 micrograms/ml) on oxidative activity of isolated mitochondria were also investigated. With unesterified chloramphenicol, inhibition of state 3 respiration was most apparent when glutamate and palmitylcarnitine were supplied as substrates. Inhibition of mitochondrial oxidation of succinate or glutamate was only detectable at 200 micrograms/ml. Inhibition of alpha-ketoglutarate oxidation was not seen at any concentration of antibiotic studied. Chloramphenicol succinate most strongly inhibited state 3 oxidation of succinate and alpha-ketoglutarate and had relatively mild effects on oxidation of glutamate and palmitylcarnitine. Succinate oxidation by submitochondrial particles was unaffected by chloramphenicol succinate, a result suggesting interference with succinate transport.

Ductus arteriosus aneurysm presenting as pulmonary artery obstruction: diagnosis and management.

The occurrence of pulmonary artery obstruction in an 8 day old infant as a complication of an aneurysm of a nonpatent ductus arteriosus is reported, together with the echocardiographic and angiographic findings. To relieve the obstruction, the aneurysm and an intrapulmonary thrombus were successfully removed with the use of cardiopulmonary bypass when the infant was 3 months old.

Aerobic capacity, obesity, and atherosclerotic risk factors in male adolescents.

Correlations between aerobic capacity, obesity, and atherosclerotic risk factors were evaluated in adolescents with low-to-moderate levels of physical fitness. Subjects with higher levels of fitness had a more favorable risk profile with decreased body mass index, lower systolic and diastolic blood pressure and plasma triglyceride levels, and higher plasma high-density lipoprotein-cholesterol levels. Simple linear regression analysis revealed an association between body mass index and blood pressure, plasma triglyceride and plasma high-density lipoprotein-cholesterol. The level of aerobic fitness as determined by exercise duration was also associated with the same atherosclerotic risk factors. However, multiple linear regression analysis demonstrated that body mass index provided the largest explanation, by those variables examined, of the interindividual variance in blood pressure, plasma triglyceride, and high-density lipoprotein-cholesterol. Aerobic fitness contributed only minimally to the variation in these risk factors. These findings suggest that if aerobic conditioning is used to modify atherosclerotic risk factors, it should be accompanied by a reduction in weight in adolescents with low-to-moderate levels of physical fitness.