Pulmonary artery growth fails to match the increase in body surface area after the Fontan operation.

OBJECTIVE: To evaluate the growth of the pulmonary arteries after a Fontan procedure. DESIGN: Retrospective review. SETTING: Two paediatric cardiology tertiary care centres. PATIENTS: 61 children who underwent a modified Fontan operation and had angiography suitable for assessment of pulmonary artery size before the Fontan procedure and during long term follow up. An atriopulmonary connection (APC) was present in 23 patients (37.7%) and a total cavopulmonary connection (TCPC) was present in 38 (62.3%). Postoperative angiograms were performed 0.5-121 months (median 19 months) after the Fontan operation. MAIN OUTCOME MEASURE: Growth of each pulmonary artery measured just before the first branching point. The diameter was expressed as a z score with established nomograms used to standardise for body surface area. RESULTS: The mean change in the preoperative to postoperative z scores of the right pulmonary artery was -1.06 (p = 0.004). The mean change in the preoperative to postoperative z scores of the left pulmonary artery was -0.88 (p = 0.003). Changes in the preoperative to postoperative z scores were more pronounced in the patients undergoing APC than TCPC, especially for the right pulmonary artery. CONCLUSION: After the Fontan operation, growth of the pulmonary arteries often fails to match the increase in body surface area.

Spontaneous-onset atrial fibrillation in a toddler with review of mechanisms and etiologies.

Atrial fibrillation is a relatively rare form of arrhythmia in the pediatric population. When it is seen in an infant or child, it is often associated with a structural heart abnormality, particularly after surgical repair or palliation of congenital heart disease. Other episodes may be associated with metabolic derangements. This report discusses the unique case of a toddler with new-onset atrial fibrillation that was devoid of a readily identifiable etiology. It also reviews the literature and the implications of such a case for the primary care practitioner.

Initial results and clinical follow-up after balloon angioplasty for native coarctation.

This study describes the initial hemodynamic results and early to late clinical follow-up, including magnetic resonance imaging and exercise testing, following balloon angioplasty for native coarctation of the aorta. We advocate this approach as an alternative to surgical intervention in select patients based on age, aortic arch anatomy, or in those patients who have coexisting cardiac defects that are amenable to transcatheter intervention.

Transvenous approach to coronary angiography in infants with tetralogy of Fallot.

A new technique is offered for selective imaging of the coronary arterial system from a transvenous approach in patients with tetralogy of Fallot as an alternative to other traditional approaches. This technique should identify important coronary anomalies while avoiding femoral arterial cannulation and compromise.

Transvenous "snare-assisted" coil occlusion of patent ductus arteriosus.

Sixty consecutive patients underwent successful transcatheter closure of patent ductus arteriosus without morbidity using a modified transvenous "snare-assisted" approach and a single elongated Gianturco coil. This technique ensures complete occlusion and avoids inadvertent embolization of the coil to undesirable sites, making transcatheter occlusion a viable alternative to surgical ligation.

Transcarotid balloon valvuloplasty with continuous transesophageal echocardiographic guidance for neonatal critical aortic valve stenosis: an alternative to surgical palliation.

Neonatal critical aortic valve stenosis is a life-threatening malformation if untreated. Before the late 1980s, the preferred treatment was surgical valvotomy; however, operative mortality was high. Early reports of transcatheter balloon dilation were encouraging, although femoral artery damage and aortic valve insufficiency were procedural limitations. With new balloon catheter technology, transumbilical, transvenous, and transcarotid approaches have been advocated, although a comparison with recent surgical results has not been performed. We compared all neonates who presented to our institution since 1985 with the diagnosis of critical aortic stenosis. Ten patients underwent surgical transventricular valvotomy and 13 patients underwent balloon valvuloplasty via a right carotid cutdown with continuous transesophageal echocardiographic guidance. Prior to intervention, all patients had either left ventricular dysfunction, an aortic valve gradient > 100 mmHg, significant mitral valve insufficiency, and/or ductal dependent systemic blood flow. All patients had successful relief of aortic valve obstruction with normalization of left ventricular function and successful discontinuation of prostaglandin E1. Use of continuous transesophageal echocardiographic guidance resulted in fluoroscopic exposure of only 12 +/- 8 minutes. At the latest follow-up, a similar proportion of patients has required additional aortic valve procedures (38% vs 25%) and overall mortality (20% vs 15%) is similar. In the transcarotid group, 9 of 13 patients (69%) have a normal appearing right carotid artery by Duplex imaging, and no neurologic events have been reported. Balloon aortic valvuloplasty via a right transcarotid approach is safe, simplifies crossing the valve, and is effective for the initial palliation of neonatal critical aortic stenosis. The use of transesophageal echocardiographic guidance reduces fluoroscopy exposure, enables accurate assessment of hemodynamics without catheter manipulation or angiography, and avoids femoral artery injury.

Effectiveness of an umbilical artery "snare assisted" approach for critical pulmonary valve stenosis or atresia in the neonate.

Thirteen neonates with critical pulmonary valve stenosis/atresia underwent successful transcatheter balloon valvuloplasty using an umbilical artery "snare assisted" approach. This technique simplifies the procedure and avoids femoral artery injury by using the umbilical artery, reduces fluoroscopy exposure, and eliminates the need for a gradational approach which reduces costs.

Transcatheter vascular occlusion of the small patent ductus arteriosus: an alternative method.

The current strategies concerning a small (

The Norwood operation and subsequent Fontan operation in infants with complex congenital heart disease.

From April 1987 to September 1993, 60 infants underwent a Norwood operation for complex congenital heart disease including hypoplastic left heart syndrome (n = 41), ventricular septal defect and subaortic stenosis with aortic arch interruption/severe coarctation (n = 7), complex single right ventricle with subaortic stenosis (n = 8), critical aortic stenosis with endocardial fibroelastosis (n = 2), and malaligned primum atrial septal defect with coarctation (n = 2). Age at operation ranged from 1 day to 3.9 months (mean 9 days, median 3.5 days). The operative mortality (< 30 days) was 33% (20 patients). Late mortality was 17% (10 patients). Nine of the 20 (45%) operative deaths occurred during the first 2 days after the operation as a result of sudden hemodynamic instability. All four infants with premature closure of the foramen ovale had pulmonary lymphangiectasia and died of pulmonary failure. Seven operative deaths have occurred in 36 patients since 1990 (19%); in the past 2 years, no operative deaths have occurred in 22 patients. Overall, there are 30 long-term survivors (50%). Twenty-one of these 30 infants have undergone a two-stage repair with a modified Fontan operation at 7.3 to 27.6 months of age (mean 18.1 months) with no mortality. Six patients have entered a three-stage repair strategy by undergoing a hemi-Fontan procedure at 6.8 to 23.0 months (mean 8.8 months) with no mortality, and two of these patients have now had their modified Fontan operation at 23.0 to 46.7 months of age with no mortality (four are still awaiting surgery). Two patients have undergone a two-ventricle repair with a Rastelli procedure, with no mortality at 7.4 and 14.1 months of age. Early in our experience, infants undergoing the Norwood operation had a high early mortality most often related to sudden hemodynamic instability. After we instituted a protocol that adds carbon dioxide to the inspired gas during postoperative mechanical ventilation, the postoperative course became more stable and there have been no operative deaths. In summary, the operative mortality for the Norwood operation continues to improve. A subsequent Fontan operation can be performed with excellent clinical results.

Captopril-induced bone marrow suppression in two cardiac patients with trisomy 21.

Neutropenia is an infrequent complication following administration of the angiotensin-converting enzyme (ACE) inhibitor, captopril. Most reports have been in adult patients, with rare reports in the pediatric population. We report two cases of neutropenia following captopril use in cardiac patients with trisomy 21. As this was not seen in patients without Down's syndrome, we postulate that patients with trisomy 21 have bone marrow which is "at risk" for suppression, and, thus warrant close evaluation while on such medications.

Coarctation of the aorta in the adolescent and adult: echocardiographic evaluation prior to and following surgical repair.

The combination of two-dimensional and continuous-wave (CW) Doppler echocardiographic imaging forms the cornerstone of diagnostic imaging in pre- or postoperative coarctation of the aorta. Because of the frequent association of other congenital heart defects, e.g., bicuspid aortic valve, a segmental imaging approach with multiple image planes should be used. CW Doppler examination from the suprasternal notch should be utilized to assess the degree of obstruction at the coarctation site in all patients. This enhances diagnostic sensitivity. CW Doppler examination can also be applied throughout exercise. Such application allows detection of relative degrees of aortic obstruction following surgical repair of coarctation that may only manifest at elevated levels of cardiac output, e.g., exercise. It aids in the identification of individuals with exercise related systolic hypertension following "successful" coarctectomy and provides a rationale for treatment with beta blockade. The methodology for applying this relatively new technique is discussed.

Developmental differences in cardiac myocyte calcium homeostasis after steady-state potassium depolarization: mechanisms and implications for cardioplegia.

We previously reported developmental differences in the response of cytosolic free calcium ([Cai]) to extracellular potassium ([Kex]) depolarization (cardioplegia) in juvenile (4 weeks post partum) and mature (12 to 18 months post partum) cardiac myocytes (rabbit). Our present study explored the physiologic basis for these observations. Single calcium-tolerant cardiac myocytes were isolated by sequential exposure to proteolytic agents, loaded with a fluorescent probe for calcium (fura-2) and [Cai] measured by standard fluorescence techniques. The response of [Cai] to [Kex] depolarization (30 mmol/L) was determined in the presence of varying levels of extracellular calcium [Caex], verapamil, ouabain, and amiloride. At nominal levels of [Caex] (0 mmol/L), no significant increases in [Cai] from the juvenile (2.1% +/- 3.3%) or mature (8.5% +/- 3.1%) myocytes were seen. At increasing [Caex], there was a progressive increase in the response of [Cai] to [Kex] depolarization in mature animals' cells (191.8% +/- 40.7%) but not in the juveniles' cells (28.0% +/- 11.5%). Exposure to verapamil resulted in an approximate 80% reduction in relative increase in [Cai] in the mature compared with 60% in the juvenile myocytes. Finally, ouabain exposure resulted in a significant increase in the relative change of [Cai] in juvenile cells (30% to 126.4% +/- 39.4%) but not in the adults' cells. This increase in the juvenile myocytes was blocked by amiloride. We conclude that increases in cardiac myocyte [Cai] after [Kex] depolarization occur predominantly through the calcium channel in the mature animal and through sodium-calcium exchange in the juvenile.

Aortic "recoarctation" at rest versus at exercise in children as evaluated by stress Doppler echocardiography after a "good" operative result.

The mechanism for exercise systolic hypertension after a "good" operative repair of coarctation of the aorta remains speculative. Twenty-four children (mean age +/- SD 10.3 +/- 3.8 years) were studied with continuous-wave Doppler echocardiography while they performed continuous, graded, maximal treadmill exercise. Patients were free of "recoarctation" based on conventional resting echocardiography. Measurements of ascending and descending aortic peak instantaneous systolic velocity were obtained at rest, throughout exercise and during recovery. Results were compared with 24 age- and gender-matched control subjects. Fifteen patients were normotensive (group 1) (peak systolic blood pressure, 147 +/- 21 mm Hg) and 9 developed systolic hypertension during exercise (group 2) (196 +/- 32 mm Hg) (p < 0.05) (control subjects, 143 +/- 21 mm Hg). Descending aortic peak systolic velocity at rest ranged from 1.50 +/- 0.27 m/s in the control group to 2.57 +/- 0.57 m/s (group 1) and 2.93 +/- 0.43 m/s (group 2) (p < 0.05, group 2 vs control). Differences were amplified at peak exercise with systolic velocity increasing to 4.26 +/- 0.61 m/s in group 2 but only to 3.61 +/- 0.70 m/s in group 1 and 2.26 +/- 0.38 m/s in control subjects (p < 0.05, group 2 vs group 1 and control). Seven patients developed a descending aortic diastolic velocity during exercise. Stepwise linear regression analysis identified 2 variables to be significant determinants of peak exercise systolic blood pressure in the "total" patient group: (1) age at exercise testing, and (2) descending aortic peak systolic velocity at peak exercise (r2 = 0.88, p < 0.001) (group 2, alone - r2 = 0.98, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Discrepancies in aortic growth explain aortic arch gradients during exercise.

OBJECTIVES: This study was conducted to evaluate the incidence and etiology of hypertension and aortic arch gradients during exercise in patients who have apparent good coarctation repair assessed at rest. BACKGROUND: The reported incidence of recurrent aortic arch obstruction (rest gradient > 20 mm Hg) after previous successful surgical repair varies from 0% to 60% and usually is associated with recurrent stenosis at the site of surgical repair. METHODS: Maximal treadmill exercise with Doppler echocardiographic gradient estimation was performed in 28 patients with a good coarctation repair at rest (normal blood pressure and arch gradient < 20 mm Hg) who had isolated coarctation repair a mean of 7.8 years previously. RESULTS: Eight (29%) developed systolic hypertension for age and a mean Doppler gradient of 45 +/- 13 mm Hg. At cardiac catheterization, the rest peak to peak systolic gradient (6 +/- 6 to 28 +/- 7 mm Hg, p < 0.001), peak systolic instantaneous gradient (16 +/- 11 to 48 +/- 9 mm Hg, p < 0.01) and cardiac index (3.5 +/- 0.7 to 5.9 +/- 1.1 liters/m per m2, p < 0.001) all increased during isoproterenol infusion. Angiographic systolic aortic arch measurements proximal to the innominate artery, left common carotid artery, left subclavian artery and the narrowest dimension at the coarctation repair site demonstrated hypoplasia at the left common carotid artery (11.8 +/- 1.7 vs. 16.7 +/- 2.9 mm/m2, p < 0.01) and left subclavian artery (11.6 +/- 1.7 vs. 15.4 +/- 3.1 mm/m2, p < 0.05) compared with findings in 10 patients with normal aortograms. Transverse aortic arch ratios were also smaller in the eight patients with abnormal findings. Preoperative angiographic ratios were not predictive of late postoperative findings. CONCLUSIONS: Exercise testing detects hypertension and arch gradients in patients with a good coarctation repair as assessed at rest. The hypertension and arch "obstruction" appear to be related to discrepancies in the growth of the transverse aortic arch proximal to the repair site, rather than a "recoarctation" of the aorta.