Reduced radiation during cardiac catheterization of infants using acquisition zoom technology

The new digital technology of obtaining images in an AZ mode effectively reduces the radiation dose to infants undergoing cardiac catheterization. Future software advances in this technique should enhance the image quality and potentially broaden its application to older patients.

Repair of an unusual type of total anomalous pulmonary venous connection

A 9-day-old, 4.5-kg female infant was diagnosed with total anomalous pulmonary venous connections by echocardiography. The unusual nature of the pulmonary veins and their connections led to cardiac catheterization and angiography. Angiography demonstrated the left-sided veins connected, via a retropulmonary artery vertical vein, to the left inominate vein whereas the right-sided pulmonary veins connected to the right superior vena cava. We repaired this lesion uneventfully by creating a neo-common pulmonary vein and anastomosing this confluence to the left atrium.

Decreased incidence of postoperative pericardial effusions after cardiac surgery for congenital heart disease

There has been a striking decrease in the incidence of postoperative pericardial effusion to 13.6%. A higher incidence of postoperative pericardial effusion was found in the winter months.

Coronary sinus ostial atresia with persistent left superior vena cava

BACKGROUND

Atresia of the coronary sinus orifice with a persistent left superior vena cava is an intrinsically benign cardiac anomaly with important surgical implications.

METHODS

THe medical records of 5 patients with atresia of the coronary sinus orifice with a persistent left superior vena cava were reviewed retrospectively, and a computer search of the world literature describing this cardiac malformation was undertaken.

RESULTS

The 5 patients ranged in age from 9 months to 5 years. In 2, the diagnosis was made preoperatively by angiocardiography, and in 3, the abnormality was found incidentally at the time of cardiotomy for repair of associated congenital heart disease. Four of the 5 patients underwent repair of associated cardiac lesions. During operation, care was taken to avoid disruption of left superior vena cava flow to prevent coronary venous obstruction. All patients survived and are doing well at follow-up.

CONCLUSIONS

Atresia of the coronary sinus orifice with persistent left superior vena cava is, in itself, a benign anomaly without physiologic consequence. However, the recognition of this lesion during repair of associated cardiac lesions is of vital importance to the cardiac surgeon. Interruption of this sole route of coronary venous drainage can potentially lead to myocardial ischemia and necrosis.

The use of intravitreal tissue plasminogen activator in the treatment of experimental subretinal hemorrhage in the pig model

PURPOSE

To clinically and surgically evaluate clot lysis in an animal model of subretinal hemorrhage after intravitreal injection of tissue plasminogen activator.

METHODS

Autologous subretinal hemorrhages were created via a transvitreal approach in 18 pigs. The next day (day 1) animals were randomly selected to receive either an intravitreal injection of 0.1 mL balanced salt solution or 0.1 mL tissue plasminogen activator (25 micrograms) followed by observation or vitrectomy a day later. On day 2, six pigs (all treated with tissue plasminogen activator) underwent a vitrectomy in which aspiration of the subretinal hemorrhage was attempted. The other eyes were evaluated for clot lysis by ophthalmoscopy at days 3, 10, and 30. All eyes were examined histopathologically.

RESULTS

The eyes that had been treated with tissue plasminogen activator demonstrated a color change at the peripheral margin, which suggested that clot lysis had occurred. At the time of the vitrectomy, the clots were liquefied partially; removal by aspiration alone, however, was not possible. Photoreceptor damage was moderate to severe by day 10 in all eyes, whether they were treated with tissue plasminogen activator or balanced salt solution. All eyes that underwent vitrectomy had moderate to severe photoreceptor damage.

CONCLUSIONS

In this animal model, intravitreal tissue plasminogen activator was associated with features that suggested partial clot lysis; tissue plasminogen activator did not produce sufficient lysis to allow surgical removal by aspiration alone, however.

Idiopathic polypoidal choroidal vasculopathy associated with retinal arterial macroaneurysm and hypertensive retinopathy

BACKGROUND

Idiopathic polypoidal choroidal vasculopathy (IPCV), the posterior uveal bleeding syndrome, and multiple recurrent serosanguineous pigment epithelial detachments in black women are a heterogeneous group of related entities seen in elderly hypertensive females. Similar associations are known for retinal arterial macroaneurysm (RAM).

METHODS

This report documents the clinical, fluorescein, and indocyanine green videoangiographic findings of two elderly black female hypertensive patients who presented with IPCV, RAM, and hypertensive retinopathy.

RESULTS

Clinical, fluorescein, and indocyanine green videoangiographic analysis of these two patients revealed hypertensive retinopathy, RAM, and anomalous polypoidal vascular networks associated with focal "bead-string" constrictions, terminal vascular loops, and polypoidal and pinpoint choroidal nodules.

CONCLUSION

Certain subgroups of IPCV and related entities and RAM may be pathophysiologically related as analogous hypertensive insults to the choroidal and retinal vascular beds.

Prenatal ultrasonographic diagnosis of ductus arteriosus aneurysm with spontaneous neonatal closure

Aneurysm of the ductus arteriosus may be either spontaneous or acquired as a complication of surgical closure of a patent duct. Patients may be asymptomatic or present with a wide spectrum of symptoms, including hoarseness, respiratory symptoms, aortic or pulmonary thrombosis or embolism, or rupture of the aneurysm. We present the first report of prenatal ultrasonographic diagnosis of isolated ductus arteriosus aneurysm. The aneurysm presented at 39 weeks as an enlarged, dilated, vascular structure 15 mm in diameter, which began at the bifurcation of the main pulmonary artery and ended in the descending aorta. Doppler imaging demonstrated turbulent flow in this lesion. Following spontaneous delivery, a bidirectional shunt in the ductus arteriosus was found on the 1st day, but the caliber of the vessel was normal. An almost completely functionally closed ductus was found on the 2nd day. Spontaneous resolution of the lesion was confirmed by magnetic resonance imaging at 4 weeks of age.

Acute changes in endothelin-1 after hemodialysis for chronic renal failure

Endothelin is a recently described, potent renal vascular and systemic vasoconstrictor peptide. To evaluate the response of this peptide to volume contraction, we measured eight baseline and posthemodialysis samples from seven children, aged 14.5 +/- 3 years, with chronic renal failure. Plasma was extracted and endothelin-1 was measured by radioimmunoassay. Dialysis was performed for a 3- to 3 1/2-hour period, and body weight decreased from 38.0 +/- 14.3 to 36.2 +/- 13.8 kg (p < 0.01) during this time. There were no significant changes in heart rate or respiratory rate after dialysis, but blood pressure fell from 127/80 +/- 22/16 to 114/72 +/- 20/21 mm Hg (p = 0.05 for the systolic pressure). Plasma endothelin-1 concentration increased from 1.5 +/- 1.2 pg/ml at baseline to 7.3 +/- 8.9 pg/ml (p = 0.06) after dialysis; the fall in body weight from dialysis correlated with the increase in endothelin (r = -0.75; p = 0.05). Thus volume contraction from hemodialysis is associated with a rise in plasma endothelin-1, which is related to the acute change in body weight.

Relation of elevated plasma endothelin in congenital heart disease to increased pulmonary blood flow

Endothelin-1 (ET), a potent vasoconstrictor peptide, has been found to be elevated in children with pulmonary hypertension associated with congenital heart defects. To evaluate the effect of pulmonary blood flow on ET concentrations, 5 ml blood samples were obtained peripherally at cardiac catheterization from 35 patients, ages 0.13 to 17 years (median 2). Plasma was extracted and ET measured by radioimmunoassay. Patients were classified into 2 groups based on the presence (group A) or absence (group B) of increased pulmonary blood flow defined as a Qp/Qs > or = 1.5. When the 13 patients (37%) in group A were compared with the 22 patients (63%) in group B there were no significant differences in age, cardiac index, or pulmonary and systemic resistances. ET concentrations were significantly higher in group A patients (median 3.25, range 0 to 16.5 vs median 0, range 0 to 6.35 pg/ml; p < or = 0.05). Pulmonary blood flow and pulmonary artery pressure were also higher in group A patients (p < or = 0.01). When patients within group A were subdivided into those with and without pulmonary hypertension, no difference was present in their ET concentrations (mean/SD: 4.4/4.3 vs 4.0/6.4 pg/ml, p = NS). Thus, ET is elevated in patients with congenital heart disease associated with left-to-right shunts and it appears that this increase is related to increased pulmonary blood flow independent of pulmonary artery pressure.

Pediatric sedation: short-term effects

A prospective investigation on the short-term effects of various sedation regimens on 549 nonhospitalized magnetic resonance (MR) patients was performed. The drugs evaluated were chloral hydrate, pentobarbital, midazolam, and diazepam (fentanyl was used for enhancement after any of these drugs). The overall safety and efficacy were quite good with all the regimens. Overall, 84% of children slept less than 8 h after the examination, 90% were drowsy and/or unsteady for less than 8 h after they awoke, and 97% resumed their usual activities by 24 h. Significant hyperactivity was seen only with pentobarbital and occurred in 8.4% of children over 8 years of age. The multiple-dose regimen of pentobarbital and fentanyl had a significant short-term effect on the children less than 8 years of age, with 35% sleeping longer than 8 h after the MR. Ten children who had needed the multiple-dose pentobarbital regimen or who had failed prior pentobarbital sedation presented for repeat sedation. Midazolam was effective in 9 of these 10 children.

Augmented norepinephrine and renin output in response to maximal exercise in hypertensive coarctectomy patients

To evaluate a possible neural or renal contribution to the hypertension that occurs in some patients following coarctation of aorta repair, 35 patients underwent graded bicycle exercise with serial measurements of plasma norepinephrine concentrations and plasma renin activity. Sixteen patients with coarctectomy who had systolic or diastolic hypertension at peak exercise were compared with 19 normotensive patients with coarctectomy. The average time interval between coarctation repair and study was significantly longer (p less than 0.05) in the hypertensive group than in the normotensive patients (12.8 +/- 4.8 versus 8.7 +/- 2.2 years). The heart rate response to exercise was similar for both patient groups. The systolic blood pressure in the hypertensive group was higher than in the normotensive group at rest in the supine and upright positions and at 5 minutes of recovery, in addition to peak exercise, and the diastolic blood pressure was increased at peak exercise. Plasma norepinephrine concentrations were significantly higher at peak exercise and during recovery in the hypertensive group than in the normotensive patients. Plasma renin activity was also significantly higher in the hypertensive group at peak exercise. These data suggest that patients with coarctectomy who have a hypertensive response to exercise have an augmented sympathetic nervous system output and increased plasma renin activity that may lead to peripheral vasoconstriction at peak exercise and that may contribute to the development of their hypertension.

Grading the severity of congestive heart failure in infants

To determine which variables most accurately define congestive heart failure (CHF) in infants, 41 patients (median age 2.5 months) were graded by four pediatric cardiologists for the presence and severity of CHF based on the following variables: amount of formula consumed per feeding, feeding time, history of diaphoresis or tachypnea, growth parameters, respiratory and heart rates, respiratory pattern, perfusion, presence of edema, diastolic filling sounds, and hepatomegaly. There were 19 patients graded as having no CHF, nine as mild, seven moderate, and six severe CHF. The most sensitive and specific variables (p less than 0.0001) for the presence of CHF were a history of less than 3.5 oz/feed, respiratory rate greater than 50/min, an abnormal respiratory pattern, diastolic filling sounds, and hepatomegaly. Moderate to severe CHF was present when patients took less than 3 oz/feed or greater than 40 min/feed, had an abnormal respiratory pattern with a resting respiratory rate greater than 60/min, and had a diastolic filling sound and moderate hepatomegaly. Severe CHF was accompanied by a heart rate greater than 170/min, decreased perfusion, and severe hepatomegaly. Thus, the grading of the severity of CHF in infants should include an accurate description of these historical and clinical variables.

Atrial natriuretic factor and sympathetic nervous output in response to volume shifts in the immature canine circulation

This study evaluated the immature circulation's response to acute shifts in intravascular volume with respect to atrial natriuretic factor and plasma catecholamines. Serial measurements were performed on thirteen beagle puppies during volume expansion with a saline and albumin solution followed by volume contraction with furosemide. Atrial natriuretic factor correlated with right (r = .73, p less than 0.001) and left (r = .62, p less than 0.001) atrial pressures and increased to much greater levels than previously reported for mature animals. Simultaneously, 10 puppies had a progressive decrease in plasma norepinephrine over the 60-minute infusion (p less than 0.05) while two puppies demonstrated a marked increase between the 30- and 60-minute samples. Furosemide increased urine output and reversed the hormonal changes caused by volume expansion. Thus a greatly augmented output of atrial natriuretic factor occurs in the immature canine circulation in response to increased atrial and pulmonary pressures, while sympathetic output remains unchanged or falls with increasing intravascular volume until a critical decrease in cardiac output triggers a catecholamine surge.

Myocardial performance and perfusion during exercise in patients with coronary artery disease caused by Kawasaki disease

For a study of the natural history of coronary artery lesions after Kawasaki disease and their effect on myocardial blood flow reserve with exercise, five such patients underwent exercise testing on a bicycle. Oxygen consumption, carbon dioxide production, minute ventilation, and electrocardiograms were monitored continuously. Thallium-201 scintigraphy was performed for all patients. One patient stopped exercise before exhaustion of cardiovascular reserve but had no evidence of myocardial perfusion abnormalities. Four patients terminated exercise because of exhaustion of cardiovascular reserve; one had normal cardiovascular reserve and thallium scintiscans, but the remaining patients had diminished cardiovascular reserve. Thallium scintigrams showed myocardial ischemia in two and infarction in one. No patient had exercise-induced electrocardiographic changes. These results indicate that patients with residual coronary artery lesions after Kawasaki disease frequently have reduced cardiovascular reserve during exercise. The addition of thallium scintigraphy and metabolic measurements to exercise testing improved the detection of exercise-induced abnormalities of myocardial perfusion.

Plasma norepinephrine levels in infants and children with congestive heart failure

To characterize the sympathetic nervous system response to congestive heart failure (CHF) in infants and children, plasma catecholamine levels were measured in 102 subjects undergoing routine cardiac catheterization (mean age 3.3 years, range 0.1 to 14.7), including 61 with left-to-right shunts. Plasma norepinephrine levels were significantly higher (p less than 0.0001) in children with CHF than in those without CHF. A highly significant association (p less than 0.0001) was found between the level of plasma norepinephrine and severity of CHF symptoms. This relation was found for CHF secondary to lesions producing a left-to-right shunt and CHF resulting from primary myocardial dysfunction. In congenital lesions with a left-to-right shunt, plasma norepinephrine levels correlated well with size of the shunt (Qp/Qs) (r = 0.75, p less than 0.001) and degree of pulmonary arterial hypertension (r = 0.70, p less than 0.001). Elevation of plasma norepinephrine concentrations in infants and children are seen with severe CHF regardless of its origin.

Gas-liquid chromatography of 3-chloropropanediol

To improve the gas chromatographic properties of 3-chloropropanediol, a phenylboronic acid derivative was prepared. This method appears to be suitable for trace analysis of the title compound. Epichlorohydrin, 1,2-propanediol, and 1,2-dichloropropanol were among the structurally related compounds shown not to interfere. The structure of the derivative was confirmed by gas chromatography-Fourier transform infrared spectroscopy utilizing a matrix isolation interface and gas chromatography-mass spectrometry.

Effects of source and particle size on the biological availability of calcium in calcium supplements for growing pigs

Five experiments were conducted to determine the biological availability of the Ca in high-Ca (calcitic) limestone, dolomitic limestone, oyster shell flour, gypsum, marble dust and aragonite for the growing pig, and to determine the influence of particle size of the Ca source on the bioavailability of Ca. A low-Ca, fortified, corn soybean meal basal diet calculated to contain .2% Ca and .6% P was used. This diet was supplemented with 0 or .3% Ca from either CaCO3 precipitate (the standard) or the test source of Ca. Diets were fed on an ad libitum basis to three to eight replicate pens of pigs (one or two/pen) for 35 to 42 d. Average initial weight of the pigs was 15 kg. At the end of each experiment the pigs were killed, the third and fourth metacarpals and metatarsals and the femurs were removed, and breaking strength and ash were determined. The increase in bone strength from feeding the test source of Ca relative to the increase in bone strength from feeding the CaCO3 standard was used to calculate the relative availability of Ca in the supplements. The bioavailability of Ca in calcitic limestone (two sources), oyster shell flour, gypsum, marble dust and aragonite was similar, ranging from 93 to 102%. However, the Ca in two sources of dolomitic limestone was less available (51 and 78%) than in the other sources. Particle size of the Ca sources (geometric mean diameter of .10 to .54 mm) did not influence the availability of Ca.