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The current article will describe how the cardiovascular risk factors of obesity, increased blood pressure, hyperlipidemia, cigarette smoking, poor physical fitness and prenatal environment impact the development of cardiovascular disease and what types of therapy can be used in the pediatric patient to modify them.

Background: Models that predict survival in neonates with left ventricular hypoplasia and critical aortic stenosis may not be applicable to neonates with left ventricular hypoplasia and coarctation., Methods and Results: We report 8 infants with severe aortic coarctation and left ventricular hypoplasia. Mean age was 18 days (range 1-48 days), and mean weight was 3.5 kg (range 2.7-4.3 kg). Associated diagnoses included mild aortic stenosis (4), ventricular septal defect (2), and venous anomalies (2). All had coarctation repair as a primary procedure (3 of these had concomitant intracardiac procedures); 7 had subsequent operations. All are alive and well 1.1-6.7 years (mean 3.1 years) after the first surgery. Progressive increases were observed in aortic and mitral diameters, and in left ventricular dimensions, areas, and volumes when the preoperative, earliest postoperative, and most recent echocardiograms were compared., Conclusions: Despite severe left ventricular hypoplasia, a two-ventricle repair is possible in selected cases. The prognostic criteria for left ventricular hypoplasia in critical aortic stenosis may not be applicable to infant coarctation. Relief of coarctation may result in the growth of the very small left ventricle, especially when the aortic root and mitral diameters are satisfactory.

Background: Minimally invasive techniques are currently in use to close atrial and ventricular septal defects (VSD). Cardiopulmonary bypass (CPB) is instituted via the femoral vessels, which may cause injury to these vessels, especially in younger patients. The objectives of this study were to demonstrate the feasibility of perventricular [corrected] closure of muscular VSD (MVSD) and paramembranous VSD (PVSD) without CPB, using the Amplatz VSD device., Methods: Five Yucatan pigs with naturally occurring PVSD (3- to 7-mm diameter) and 5 dogs with surgically created MVSD (6- to 14-mm diameter) were subjects of this study. The VSDs were closed intraoperatively with a 7-French delivery sheath inserted through the free wall of the right (n = 5) or left ventricle (n = 5), under epicardial echocardiogram guidance. The animals were followed for 3 months., Results: There was no operative mortality. All MVSD closed after placement of the device. Closure rate of PVSD was 4 of 5 after placement and 3 of 5 after 3 months. One pig developed aortic incompetence at the last follow-up., Conclusions: Perventricular closure of MVSD and PVSD is feasible. Avoidance of CPB can decrease recovery time, its complications, and trauma to the femoral vessels.

Access to the central circulation can be difficult in small infants, particularly when normal anatomic landmarks have been altered. We describe a new technique that utilizes any existing central catheter to establish additional sites of vascular access. A 4 Fr end hole catheter is advanced under fluoroscopic guidance to the desired site of new vascular access. A 10-mm Amplatz snare catheter is advanced through the end hole catheter and the loop opened within the target vessel lumen. The snare is then used to guide percutaneous placement of a Cope wire through a 21-gauge needle and then to pull the wire into the central circulation. New access is then achieved by introducing an additional catheter over the guidewire. This technique has now been successfully utilized 16 times in 13 patients. Snare assistance is a safe and effective technique that provides a reliable means of establishing additional secure vascular access. Cathet. Cardiovasc. Intervent. 47:315-318, 1999., (Copyright 1999 Wiley-Liss, Inc.)

A 2100-g neonate underwent a two-ventricular surgical repair of a right ventricle-dominant unbalanced atrioventricular septal defect associated with the heterotaxy syndrome and sinus node dysfunction. Postoperative congestive heart failure persisted despite bradycardia management by temporary ventricular pacing. Spectral Doppler echocardiographic analysis of pulmonary venous inflow and aortic outflow patterns demonstrated significant improvement with transesophageal atrial pacing. Extended transesophageal pacing was performed for two days, resulting in dramatic clinical improvement. This is the first report of extended transesophageal atrial pacing complementing Doppler echocardiography predicting an improved outcome with permanent atrial pacing.

Refractory atrial arrhythmias in late postoperative Fontan patients are usually associated with residual hemodynamic abnormalities and result in significant morbidity and mortality. Surgical revision of the Fontan anastomosis may improve hemodynamics without eliminating tachycardia. This study sought to assess the impact of surgical cryoablation of the arrhythmia circuit at the time of Fontan conversion on the clinical recurrence of tachycardia. Sixteen consecutive atriopulmonary Fontan patients with refractory atrial arrhythmias underwent surgical conversion to lateral tunnel total cavopulmonary anastomosis (15) or Fontan revision (1 patient). The initial 4 patients underwent Fontan conversions alone, without specific arrhythmia surgery. The subsequent 12 patients underwent electrophysiologically guided cryoablation of the tachycardia circuits at the time of surgical conversion. The mean age at Fontan revision was 15.6 +/- 3.8 years. Cryoablation was directed to 3 identified major tachycardia circuits: the inferomedial right atrium, the superior rim of the prior atrial septal defect patch, and along the lateral right atrial wall. Transmural antitachycardia pacemakers were implanted in 11 of the 16 patients. There was no surgical mortality in either group, and all patients improved in functional classification. All patients not undergoing cryoablation experienced recurrent symptomatic tachycardia requiring antiarrhythmic therapy (median follow-up, 54 months) versus 2 of 12 patients receiving cryoablation (median follow-up, 25 months; p <0.02). Thus, surgical cryoablation of the arrhythmia circuit at the time of Fontan conversion is highly effective in the management of refractory atrial arrhythmias, and is superior to Fontan conversion alone.

The role that the central sympathetic nervous system plays in the development of obesity hypertension and insulin was evaluated by feeding dogs a high fat diet with or without clonidine treatment. Thirteen adult mongrel dogs were chronically instrumented and randomly assigned to receive either a high fat diet and no clonidine (n=6) or a high fat diet plus clonidine (n=7), 0.3 mg BID. Blood pressure, heart rate, plasma insulin, and electrolytes were measured daily. Insulin resistance was assessed with a multiple-dose euglycemic clamp (1, 2, and 30 mU. kg-1. min-1) before and after 1, 3, and 6 weeks of the high fat diet. Clonidine prevented the hypertension, tachycardia, and insulin resistance associated with feeding dogs the high fat diet but did not affect weight gain. The present study suggests that the central sympathetic nervous system plays a critical role in the development of both insulin resistance and hypertension associated with feeding dogs a high fat diet.

Background: Mitral valve remodeling techniques were applied to 26 infants and children (mean age, 6.0 years, range, 0.4 to 15.9 years) with various forms of congenital mitral valve disease over a 7-year period. Patients with atrioventricular canal, L-transposition and single ventricle were excluded. Intraoperative transesophageal echocardiography (TEE) was utilized to assess the repair and guide the need for immediate intervention., Methods: Twenty-one patients had mitral regurgitation: 10 with cleft anterior mitral leaflet, 7 with annular dilatation, 1 with normal leaflets with an obstructing cord, 2 with prolapsed leaflets and elongated cords, and 1 with restricted leaflet motion, normal papillary muscles, and shortened cords. Of the 5 mitral stenosis patients, 3 had supravalvular mitral ring, 1 had midvalvular mitral ring, and 1 had a parachute valve. Three of the mitral stenosis patients had additional stenotic lesions. Concurrent repair of associated lesions was performed in 21 patients (78%)., Results: Operative mortality was 3.8% (n = 1). There were no late deaths. Immediate rerepair in 4 patients resulted in improved function. All mitral stenosis patients improved. A total of 20 mitral regurgitation patients (95%) improved; 1 required mitral valve replacement. Mean follow-up is 31 months (range, 2 to 81 months). All patients are in New York Heart Association functional class I or II., Conclusions: Mitral valve repair can be successfully performed in infants and children with excellent short- and midterm results. Assessment using transesophageal echocardiography can guide the necessity for immediate rerepair to achieve improved function.

Endocarditis requiring surgical intervention in children is uncommon. Individualized operative therapy must be fashioned to the particular pathology of each case. In this case we describe mitral anterior leaflet homograft patch augmentation valvuloplasty, subaortic homograft patch closure of a large mycotic aneurysm, and homograft aortic root replacement in a 3-year-old patient with endocarditis after remote repair of complete atrioventricular canal.

Background: Coronary artery fistula (CAF) is a rare congenital anomaly that can be complicated by intracardiac shunts, endocarditis, myocardial infarction, or coronary aneurysms. Recent reports have emphasized the efficacy of percutaneous transcatheter techniques. The purpose of this article is to review a 28-year surgical experience with CAF as a standard for comparison and to discuss the emergence and efficacy of transcutaneous catheter coil embolization as an alternative form of therapy., Methods: From 1968 to 1996, 17 patients (age, 6 weeks to 16.5 years; mean age, 5.5 years) were diagnosed with CAF: 8 of 12 by echocardiography and 17 of 17 by cardiac catheterization. All patients with isolated CAF (n = 13) were asymptomatic despite significant clinical, electrocardiographic, and chest roentgenographic findings in 10. Sixteen had congenital CAF and 1 had acquired CAF after tetralogy of Fallot repair with injury of the anomalous left anterior descending coronary artery. Associated anomalies included tetralogy of Fallot (2), atrial septal defect (1), and patent ductus arteriosus (1). Nine fistulas originated from the right coronary artery and eight from the left. Drainage was to the right ventricle (9), right atrium (4), pulmonary artery (3), and left atrium (1)., Results: All patients had a median sternotomy with epicardial or endocardial ligation. Cardiopulmonary bypass was used in 8; 1 of these (iatrogenic CAF) required distal internal mammary artery bypass graft. There were no operative or late deaths. Follow-up evaluation by physical examination (17), echocardiography (8), and catheterization (2) showed no evidence of recurrent or residual CAF. A retrospective review of the 16 available cine cardioangiograms showed that coil embolization was possible in, at most, 6 patients., Conclusions: Early surgical management of CAF is a safe and effective treatment resulting in 100% survival and 100% closure rate. Transcatheter embolization is a reasonable alternative to standard surgical closure in only a very small, select group of patients. These surgical results should be considered the standard against which transcatheter techniques are compared.

The current study evaluated both the time course of insulin resistance associated with feeding dogs a high-fat diet and the relationship between the development of insulin resistance and the increase in blood pressure that also occurs. Twelve adult mongrel dogs were chronically instrumented and randomly assigned to either a control diet group (n = 4) or a high-fat diet group (n = 8). Insulin resistance was assessed by a weekly, single-dose (2 mU.kg-1.min-1) euglycemic-hyperinsulinemic clamp on all dogs. Feeding dogs a high-fat diet was associated with a 3.7 +/- 0.5 kg increase in body weight, a 20 +/- 4 mmHg increase in mean blood pressure, a reduction in insulin-mediated glucose uptake [(in mumol-kg-1.min-1) decreasing from 72 +/- 6 before to 49 +/- 7 at 1 wk, 29 +/- 3 at 3 wk, and 30 +/- 2 at 6 wk of the high-fat diet, P < 0.01]. and a reduced insulin-mediated increase in cardiac output. In eight dogs (4 high fat and 4 control), the dose-response relationship of insulin-induced glucose uptake also was studied. The whole body glucose uptake dose-response curve was shifted to the right, and the rate of maximal whole body glucose uptake was significantly decreased (P < 0.001). Finally, we observed a direct relationship between the high-fat diet-induced weekly increase in mean arterial pressure and the degree to which insulin resistance developed. In summary, the current study documents that feeding dogs a high-fat diet causes the rapid development of insulin resistance that is the result of both a reduced sensitivity and a reduced responsiveness to insulin.

Background: Current corrective surgical approaches for the Taussig-Bing heart include arterial switch with ventricular septal defect (VSD) closure and intraventricular repair as described by Kawashima., Methods: Between 1983 and 1994, 20 children underwent intracardiac repair of Taussig-Bing anomaly. Mean age at operation was 17 months (range, 1 week to 9 years). Prior palliation included pulmonary artery band (15) with coarctation repair (8) and atrial septectomy (1). Arterial switch with VSD closure was performed in 16 patients, 10 with anteroposterior great arteries. Kawashima repair was performed in 4 patients, all with side-by-side great arteries., Results: After arterial switch, there was one operative death (6.2%) due to myocardial ischemia and three late deaths (18.7%) due to pulmonary hypertension, gastrointestinal bleeding, and acute lymphocytic leukemia. In the Kawashima repair group there have been no deaths. After arterial switch, 9 patients underwent 11 reoperations for residual coarctation (3), residual pulmonary artery stenosis (2), aortic valve replacement, aortic valvuloplasty, unrecognized VSD, mitral valvuloplasty, mediastinitis, and pacemaker insertion. After Kawashima repair, 1 patient underwent reoperation for baffle stenosis and 1 for an unrecognized VSD., Conclusions: For children with Taussig-Bing anomaly, the Kawashima intraventricular repair (for side-by-side great arteries) preserves the native aortic valve and avoids coronary dissection. The arterial switch operation with VSD closure can be applied without ventriculotomy to all great artery relationships and allows neonatal repair with or without concomitant coarctation repair. Both techniques yield excellent early and intermediate-term results despite the high rates of prerepair palliation and postrepair reoperation for both groups.

This study evaluated both cardiac hemodynamic and metabolic effects of a graded intracoronary artery infusion of insulin in four normal and five obese anesthetized dogs. Dogs were anesthetized with isoflurane, a catheter was advanced under fluoroscopic guidance into the coronary sinus and great cardiac vein, and a 20-MHz 3F coronary Doppler catheter was advanced into either the mid left anterior descending or circumflex coronary artery. A graded intracoronary insulin infusion was administered (starting at 0.3 mU/min and doubling every 40 minutes until a maximum dose of 2.4 mU/min was achieved). Coronary glucose extraction, coronary blood flow velocity, and coronary artery size were measured at each infusion rate. An intracoronary artery infusion of insulin stimulated myocardial glucose uptake in normal dogs. However, in high-fat-fed dogs, weight gain was associated with a reduction in the ability of insulin to promote glucose uptake by cardiac muscle and a rightward shift in the dose-response curve. In normal dogs, an intracoronary insulin infusion resulted in an increase in coronary blood flow and coronary vasodilation (with insulin coronary vascular resistance index decreases to 0.72 +/- 0.06, P<.01), whereas with weight gain the vasodilator response to insulin was lost. The loss of coronary artery vasodilation to local hyperinsulinemia in fat-fed dogs is consistent with other reports in obese or hypertensive humans that document an impairment in the action of insulin to increase skeletal muscle blood flow.

Although controversy exists as to the role that insulin resistance and hyperinsulinemia play in the pathogenesis of hypertension, data are presented that strongly suggest that selective insulin resistance and hypertension are directly related. This paper summarizes how insulin resistance may be linked to obesity hypertension and describes some of the other cardiovascular implications that insulin resistance may have in the hypertensive obese individual.

Objective: To determine whether the lipid abnormalities observed in obese adolescents are associated with insulin resistance., Methods: We evaluated the relationship between lipid levels and insulin resistance in 82 obese adolescents. Insulin resistance was assessed by fasting insulin level and sum of the insulin values after an oral glucose tolerance test in all 82, and were compared with data from 40 nonobese adolescents. Whole-body glucose uptake during euglycemic hyperinsulinemia (M value) was performed in 19 of the obese adolescents and compared with that of 24 nonobese young adults., Results: The obese adolescents had significantly elevated low-density lipoprotein cholesterol (LDL-C) (3.09 +/- 0.73 mmol/L; 119 +/- 28.2 mg/dl) and triglycerides (1.22 +/- 0.62 mmol/L; 108 +/- 54.6 mg/dl) and low high-density lipoprotein cholesterol (HDL-C) levels (0.94 +/- 0.24 mmol/L; 36 +/- 9.1 mg/dl) when compared with values in the nonobese subjects. M values were significantly depressed in the obese compared with the nonobese subjects. Adiposity significantly correlated with low HDL-C and elevated triglyceride values. From the variables representing insulin resistance, the strongest correlation with the abnormal lipid profile was found for the M value. A stepwise multiple regression analysis revealed that the M value was the only step entered into the relationship for triglycerides and LDL-C, and both M value and fasting insulin were entered for HDL-C., Conclusion: In obese adolescents the degree of insulin resistance explains a significant portion of the variance in the levels of triglycerides, LDL-C, and HDL-C.

Adult-onset cardiovascular disease has its origin in childhood. During the past year there have been a number of articles that have dealt with the effects of fetal nutrition on the development of cardiovascular disease in adult life, identification of the child at high risk for the development of essential hypertension, the effects of passive smoking as a risk factor for coronary artery disease, and strategies for diagnosis and treatment for familial hypercholesterolemia. Two of the most important observations over the past year are that there appears to be a significant relationship between fetal and early childhood nutrition and the risk of developing many of the cardiovascular diseases seen in adult individuals and that environmental tobacco smoking, including smoke at work, results in an increased risk of developing coronary heart disease.

Substantial epidemiologic evidence has indirectly implicated sodium intake in the pathogenesis of hypertension. The concept of sodium-sensitivity as a cause of essential hypertension has been addressed by many investigators, yet the pathogenesis of this salt-sensitivity remains unclear. Although not well appreciated, most studies have shown that regardless of sodium intake or the presence or absence of hypertension, sodium-sensitive subjects tend to weigh more than sodium-resistant subjects. Insulin-resistance has been postulated to be responsible for enhanced sodium retention in obese individuals; therefore, insulin-resistance may be critical to the pathogenesis of sodium-sensitivity in individuals with essential hypertension. This article summarizes the data relating insulin and or insulin-resistance to sodium sensitivity in obesity, diabetes, and in non-obese subjects with essential hypertension.

Balloon valvuloplasty and angioplasty have become accepted alternatives to surgery for valvar stenosis and coarctation of the aorta. Balloon dilation avoids a potentially painful operation, the long postoperative recovery, and at the same time offers substantial cost savings. However, such advantages are meaningless if the safety of the interventional procedure does not match or surpass the results of conventional surgery. This review summarizes a number of studies that compare the natural history of surgical therapy with that of balloon pulmonary and aortic valvuloplasty and balloon coarctation angioplasty. It appears that, regardless of age, balloon valvuloplasty is preferable to surgical valvotomy. For both aortic stenosis and coarctation of the aorta, balloon valvuloplasty and surgical valvotomy produce comparable relief of the hemodynamic obstruction. However, because the length of follow-up after the balloon angioplasties has been short, the actual risk of developing severe aortic regurgitation (postaortic valvuloplasty) and aortic aneurysms (postcoarctation angioplasty) has not been trivial, a large prospective follow-up of both of these interventional procedures will be mandatory before either can be judged superior to surgical therapy.

Although heart, heart-lung, or lung transplantation is performed in more than 200 children annually, the number of patients referred for such procedures is considerably greater, and little is known about the outcome of those referrals. To determine the outcome of pediatric transplant referrals we reviewed the follow-up of 31 patients evaluated at our institution for heart (24), heart-lung (three), or lung (four) transplantations between January 1991 and September 1992. Indications included hypoplastic left heart syndrome (seven patients), cardiomyopathy or myocarditis (seven patients), and postoperative congenital heart disease (10 patients) for heart transplantation; Eisenmenger's syndrome (three patients) for heart-lung transplantation; and primary pulmonary hypertension (two patients), broncho pulmonary dysplasia, and cystic fibrosis for lung transplantation. Only 14 of 31 referred patients were listed for transplantation; the remaining 17 patients either improved when medical therapy was maximized (nine patients), died within days of referral (three patients), refused (two patients), chose alternate surgery (one patient), were medically unacceptable (one patient), or are currently undecided (one patient). To date 7 of 14 patients listed have undergone successful heart transplantation; the remaining seven patients either improved and did not require transplantation (two patients), refused (one patient), died waiting (one patient), are currently awaiting a donor (one patient), or underwent Norwood procedure because of donor unavailability (two patients). Thus including patients who died before listing, only 14 of 31 referrals (45%) were deemed in need of a transplant.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypertension is known to place the individual with IDDM at high risk for the development of both renal and cardiovascular disease. Recent data suggest that aggressive antihypertensive therapy (angiotensin I converting enzyme inhibitors, prazosin, and calcium channel blockers) have significantly improved overall prognosis and long-term survival for individuals with IDDM. Because in individuals with IDDM the development of both hypertension and renal disease has its roots in childhood, it is important that early and effective antihypertensive treatment begin there.

Although controversy exists as to the role that insulin resistance and hyperinsulinemia play in the pathogenesis of hypertension there are ample data from both obese and nonobese subjects strongly suggesting that selective insulin resistance, hyperlipidemia, and essential hypertension are directly related. It is therefore mandatory that the evaluation of both lipid profile and insulin sensitivity needs to be made in all patients with essential hypertension. In addition it appears that childhood obesity is the single marker of the child at risk for the development of cardiovascular disease later in life.

Although cardiovascular disease is an uncommon cause of hypertension, the number one cardiovascular cause of hypertension, coarctation of the aorta, is easy to diagnose and treat. It is therefore mandatory that every individual who is evaluated for hypertension should have blood pressures measured in the arms and legs. The other, more uncommon cardiovascular causes of hypertension (Table 1), also can usually be diagnosed from a thorough history and physical examination.

Background: Although overall outcome has improved, pulmonary atresia with intact septum remains a difficult surgical and clinical problem. To determine whether an early right ventricular outflow patch will result in biventricular repair for this lesion, we reviewed the long-term follow-up (5.8 +/- 0.8 years) of 19 newborns who underwent repair between 1979 and 1990., Methods and Results: An early right ventricular outflow patch was placed in 15 of 19 newborns; in the remaining four, this was preceded by an aortopulmonary shunt. Prostaglandin E1 infusion postoperatively eliminated the need for shunt in 14 of 15. Coronary sinusoids were ligated in three newborns. Based on right ventricular morphology, the newborns were divided into two groups: group 1 (tripartite, n = 9) and group 2 (bipartite and monopartite, n = 10). Before surgery, group 1 had significantly larger right ventricular volumes (23.6 +/- 3.7 versus 5.2 +/- 1.1 ml/m2, p < 0.002). Five-year survival was 79% for the entire series. Four infants, all group 2, died within 12 months of their initial surgery. Fourteen of 15 survivors (nine group 1 and five group 2) currently are acyanotic and New York Heart Association functional class I. A biventricular repair was achieved in 12 of 15, and three other children are awaiting evaluation. All 15 survivors had significant right ventricular and tricuspid annulus growth., Conclusions: Our data suggest that early placement of a right ventricular outflow patch in infants with pulmonary atresia and intact ventricular septum, regardless of right ventricular anatomy, results in an excellent chance for biventricular repair.

To determine if physiologic changes of insulin are capable of inducing sodium retention in insulin-resistant patients, we evaluated the ability of an oral glucose tolerance test to alter urine sodium excretion in 32 obese subjects (13.3 +/- 1 years, weight 82 +/- 5 kg, mean arterial pressure 89.3 +/- 1.5 mm Hg) and 13 nonobese subjects (13.8 +/- 2 years, weight 46 +/- 4 kg, mean arterial pressure 74.5 +/- 2.6 mm Hg). After an overnight fast, subjects were placed in water diuresis and fasting insulin and glucose levels were drawn. Three 30-minute urine collections were obtained for baseline urine sodium excretion. The oral glucose tolerance test was administered with glucose and insulin levels drawn at 15, 30, 45, 60, 90, and 120 minutes. During the oral glucose tolerance test, four 30-minute urine collections were obtained for urine sodium excretion. Serum glucose levels at baseline and throughout the glucose tolerance test did not differ between obese and nonobese subjects. Baseline insulin levels were elevated significantly in the obese (20 +/- 3 microU/mL) compared with the nonobese (5 +/- 0.7 microU/mL) subjects. Furthermore, insulin levels remained significantly elevated in the obese subjects compared with the nonobese subjects throughout the glucose tolerance test (118 +/- 19 vs 49 +/- 6 microU/mL, obese vs nonobese subjects at 1-hour post-glucose tolerance test).(ABSTRACT TRUNCATED AT 250 WORDS)

We assessed pediatric cardiology research by reviewing pediatric cardiology abstracts submitted in 1990 to the Society of Pediatric Research, American Academy of Pediatrics, and American Heart Association national meetings. Included were accepted and rejected studies. Abstracts were reviewed for disease being studied, methodology used to answer the research question, study design, and acceptance/rejection. Abstracts were analyzed from 123 institutions, 81 American and 42 foreign. Out of 423 abstracts, 307 (72.6%) were clinical and the remainder were basic science investigations. Slightly more than half of the clinical submissions were related to congenital heart disease. Coronary artery disease and inflammatory diseases accounted for 12% of clinical submissions. Echocardiography, clinical outcome measures, and electrophysiology were the most common research methodologies. Almost 80% of basic science research was performed in normal tissues; animal physiology, fetal physiology, and cellular/biochemical studies were the most common methodologies. With regard to study design, half of the clinical studies were retrospective and only 6% were either prospective epidemiologic or prospective controlled intervention trials. For basic sciences, 38% of abstracts were descriptions of phenomena and 62% were hypothesis testing, with developmental hypotheses being most common. Acceptance rates favored higher quality study design. However, areas of greatest interest to cardiologists, congenital heart disease, cardiomyopathy, and electrophysiology, had poorer quality study design than did other areas. We have shown broad interest in pediatric cardiology research. However, clinical studies frequently were retrospective or had uncontrolled study designs. Basic science research was performed at a small number of institutions and emphasized either description of phenomena or developmental biology of normal tissues.

To determine if structural changes in forearm resistance vessels are associated with insulin resistance, we evaluated the relation between minimum forearm vascular resistance and insulin resistance in 95 obese adolescents before and after weight loss. Insulin resistance was assessed by fasting insulin levels and sum of insulin values after an oral glucose tolerance test in all 95 subjects and whole body glucose uptake during euglycemic hyperinsulinemia in 35 of 95 subjects. Structural changes in forearm vessels were assessed by measurement of minimum forearm vascular resistance during 10 minutes of ischemic exercise. As compared with our normal values, obese adolescents had a significantly (p less than 0.01) decreased maximal forearm blood flow (41.6 +/- 1.4 versus 67.1 +/- 2.4 ml/min/100 ml) and increased minimum forearm vascular resistance (2.9 +/- 0.4 versus 1.6 +/- 0.7 mm Hg/ml/min/100 ml). There was a significant relation (p less than 0.01) between minimum forearm vascular resistance and fasting insulin, sum of insulins, and whole body glucose uptake. After a 20-week weight-loss program, minimum forearm vascular resistance decreased (3.0 +/- 0.3 versus 2.0 +/- 0.2, p less than 0.01), maximal forearm blood flow increased (41 +/- 2.3 versus 57.4 +/- 3.9, p less than 0.01), and forearm volume remained unchanged. We also observed a significant (p less than 0.01) relation between the decrease in minimum forearm vascular resistance and the decrease in fasting insulin (r = 0.29), decrease in sum of insulins (r = 0.42), and increase in whole body glucose uptake (r = 0.63).(ABSTRACT TRUNCATED AT 250 WORDS)

Current therapy of congenital or acquired stenoses of the peripheral pulmonary arteries and superior vena cava are frequently ineffective. This report describes our initial experience with the use of a balloon-expandable stainless steel stent to treat experimentally created branch pulmonary artery and superior vena cava stenosis. Fifteen adult mongrel dogs had surgically created stenoses of either a branch pulmonary artery and/or superior vena cava. A balloon-expandable stainless steel (0.076 mm), 3 cm long, intravascular stent was used in all animals. Stents were successfully placed in 13 of 15 dogs (nine with branch pulmonary stenosis and four with superior vena caval stenosis) with hemodynamic and angiographic relief of the stenoses in all. In three animals, successful stent placement was not accomplished because the distal right pulmonary artery was found to be totally obstructed in two and in one dog with combined vena cava and pulmonary stenosis the distal right pulmonary artery was so severely stenotic that the stenosis could not be crossed. Repeat catheterization performed 6 months following stent placement documented persistent gradient relief and angiographic evidence of unobstructed flow through the stent without thrombus formation and with patent side branch vessels. Our preliminary results suggests that balloon-expandable stents are a potential therapy for the treatment of branch pulmonary artery and superior vena cava stenoses.

We discuss how to identify the child at risk for developing or having heart disease. We describe both the child at risk for developing adult-onset heart disease and the child or fetus at risk for having congenital heart disease. With respect to the child at risk for developing adult-onset heart disease, we concentrate on how four risk factors (cigarette smoking, hyperlipidemia, reduced physical activity, and obesity) affect the development of cardiovascular disease, and we review the types of therapy currently being used to modify them. We also discuss the etiological factors related to the risk of developing congenital heart disease, such as single-gene conditions, known cardiac teratogens, chromosomal anomalies, and multifactorial inheritance.

Interventional cardiac catheterization has become a standard part of the practice of pediatric cardiology. In this review, articles on pediatric interventional catheterization that have been published over the past 2 years are summarized. The interventional procedures have been divided into the following: lesions, pulmonary valve, aortic valve, mitral valve, coarctation of the aorta, branch pulmonary artery stenosis, device closure of septal defects, and miscellaneous lesions. In addition, within these lesions the articles have been further categorized in the following manner: 1) large collaborative studies defining the short-term efficacy and complications associated with many of the interventional procedures; 2) follow-up studies that now define the intermediate (1 to 8 years) hemodynamic results and complications associated with the various interventional procedures; 3) the reports of new cardiac lesions that can be treated within the catheterization laboratory; and 4) the description of new technologies that have improved the results or expanded the scope of interventional pediatric cardiology.

Since 1985 balloon angioplasty, followed by surgical repair if angioplasty is unsuccessful, has been used as a treatment strategy for eligible children with discrete native coarctation of the aorta. Although balloon angioplasty has been successful in most patients, this strategy is appropriate only if surgery is safe and effective in children in whom angioplasty does not succeed. To address this issue, the surgical procedure and clinical outcome in 11 children who underwent surgery after unsuccessful balloon angioplasty (defined as a residual systolic gradient greater than 20 mm Hg in 10 and a saccular aneurysm in 1) were evaluated. Data for subjects were compared with data for a control group of seven children who had surgical repair of a discrete coarctation without prior angioplasty during the same time period. In the study group, balloon angioplasty was performed at 4.3 +/- 1.2 years of age, resulting in a balloon/isthmus ratio of 0.98 +/- 0.05 and decreasing mean peak systolic gradient from 54 +/- 3 to 27 +/- 2 mm Hg (p less than 0.001). Follow-up angiography (n = 7) or nuclear magnetic resonance imaging (n = 4) documented a discrete residual stenosis in 10 patients and a small saccular aneurysm in 1. Collateral circulation decreased in three patients. The subsequent surgical procedure and its outcome were similar in the study and control groups. Chylothorax was the only complication, occurring in one child from each group. No paraplegia or mortality occurred. Pathologic examination revealed irregular intimal surfaces with small flaps of intima in 5 of 10 resected specimens from the study group and in 2 of 6 from the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship between fatfold thickness and fat mass of 101 male and 66 female adolescents (10-16 yr) was examined with the allometric equation y = bx a . Body composition was assessed by underwater weighing and 5 fatfolds were measured: triceps, subscapular, suprailiac, abdominal, and thigh. Percent body fat ranged from 4.9% to 56.1%. The log of each fatfold thickness was plotted versus the log of fat mass. All the relationships were linear and exhibited monophasic allometry. All the alpha coefficients (slope of the log-log plots) exhibited positive allometry. The prepubescent male and female alphas were similar and had the same pattern. The pattern contrasted the trunk with the extremity fatfolds. No differences (P > .05) were found between the alphas for the pubescent males. The triceps alpha of the pubescent females was less (P < .05) than the subscapular, suprailiac, and abdominal alphas. The thigh, subscapular, suprailiac, and abdominal alphas were not significantly (P > .05) different. In conclusion, the trunk was the predominant site of subcutaneous fat deposition for prepubescents, while pubescents exhibit a more general pattern of fat distribution. © 1992 Wiley-Liss, Inc., (Copyright © 1992 Wiley-Liss, Inc., A Wiley Company.)

Post-meal energy expenditure (TEM) was compared for 14 healthy obese (body fat = 45.3%, body mass index, BMI = 35.9 kg m-2) and 9 healthy nonobese (body fat = 20.7%, BMI = 17.8 kg m-2) adolescent girls. The test meal for both groups was a standard 3348.8-kJ, 0.473-1 chocolate milkshake of 15% protein (casein), 40% fat (polyunsaturated/saturated ratio = 0.05; 75 mg cholesterol) and 45% carbohydrate (lactose and sucrose). Glucose, insulin and resting energy expenditure (RMR) were measured at rest prior to meal consumption and 20, 40, 60, 90, and 120 min after the meal. Cumulative net TEM was calculated as the integrated area under the TEM curve with RMR as baseline. Reliability was assessed by retesting 4 subjects, and a placebo effect was tested by administering a flavored energy-free drink. Results indicated high reliability and no placebo effect. The meal resulted in a greater rise in insulin and glucose for the obese compared to the nonobese subjects (P < or = 0.05), and a significant TEM for both groups (P < or = 0.05). The cumulative TEM (W kg-1) was 61.9% greater for the nonobese (P < 0.01) when expressed relative to body mass, and 33.2% greater for the nonobese (P < or = 0.01) when expressed relative to the fat-free body mass. Expressed relative to the meal, the TEM was 25.5% less for the obese (P < 0.01). The data support an energy conservation hypothesis for obese female adolescents.

The practice of pediatric cardiology has undergone remarkable changes over the past decade. Cardiac structural abnormalities may frequently be diagnosed with echocardiography alone, and treatment for many of these structural problems may be corrected during cardiac catheterization. Arrhythmia diagnosis and management have made similar progress, such that diagnosis of arrhythmia mechanisms and catheter ablative therapy may be performed during a single procedure, sparing the young patient a lifetime of antiarrhythmic drug therapy. Cardiac transplantation is now included among the treatment options for some patients with severe congenital or acquired cardiac abnormalities unresponsive to standard therapy. In this paper, we provide a brief description of current applications of recent advances in the practice of pediatric cardiology.

To determine the long-term efficacy of apical left ventricular to aortic conduits in palliating complex left ventricular outflow obstruction, we reviewed our entire experience of 20 pediatric patients who underwent placement of a composite porcine valve-bearing conduit from the left ventricular apex to the aorta from November 1977 to April 1987. There were two early postoperative deaths, both in infants less than 2 months of age at the time of surgery. The remaining 18 patients had successful conduit placement with significant relief of the left ventricular outflow obstruction. Conduits have remained functional from 3 to greater than 9 years after initial placement. Long-term maintenance of a well-functioning conduit was limited by conduit heterograft valve dysfunction secondary to degeneration and calcification, with a 3-year conduit survival of 80 +/- 9% and a 7-year survival of 52 +/- 11%. Clinical identification of conduit valve insufficiency was found to be a useful early indicator of impending conduit failure, frequently preceding other signs and symptoms of conduit valve dysfunction. Eight patients required reoperation for conduit failure, and there were two late deaths associated with conduit valve dysfunction. Other long-term complications were rare. No thromboembolic events occurred despite avoidance of anticoagulant therapy, and there were no documented episodes of bacterial endocarditis. Thus, apical aortic conduit placement is an effective surgical technique for intermediate palliation of complex left ventricular outflow obstruction and may be useful in selected pediatric patients as a staging procedure before left ventricular outflow reconstruction.

Increased pulmonary blood flow and pulmonary hypertension are frequent problems in infants with congenital heart disease. Although the use of pulmonary artery banding to limit pulmonary blood flow has decreased, the procedure may still be beneficial in certain forms of complex heart disease. The ability to noninvasively relieve the obstruction caused by the band may significantly reduce later operative complexity or even avoid reoperation entirely. The present study evaluated the effectiveness of a balloon-dilatable pulmonary artery band. Twenty 1-week-old dogs had a band of an absorbable suture material (Vicryl; Ethicon, Inc., Somerville, N.J.) placed around the main pulmonary artery. Eight dogs underwent angioplasty 6 months after band placement and also underwent follow-up catheterizations 3 and 6 months after angioplasty. Balloon angioplasty acutely reduced both the right ventricle-pulmonary artery pressure gradient (from 37 +/- 7 mm Hg to 3 +/- 1 mm Hg, p less than 0.001) and the right ventricular systolic pressure (from 62 +/- 8 mm Hg to 32 +/- 2 mm Hg, p less than 0.01). At follow-up the gradient remained low, measuring 4 +/- 1 mm Hg at 3 months and 3 +/- 1 mm Hg at 6 months. Twelve dogs did not undergo balloon dilatation until 12 months after band placement to determine whether any obstruction persisted and whether the band could be relieved after long-term placement. These 12 dogs had progressive increases in right ventricle-pulmonary artery gradient, from 27 +/- 3 mm Hg at 6 months to 43 +/- 4 mm Hg at 12 months. Ten of these dogs underwent dilation 1 year after pulmonary artery band placement. This dilation significantly reduced the right ventricular outflow tract gradient (from 43 +/- 4 mm Hg to 1 +/- 1 mm Hg, p less than 0.001). The remaining two dogs underwent successful partial dilation of the band 12 months after placement. This study demonstrated that a pulmonary artery band of absorbable suture material maintains effective right ventricular outflow tract obstruction for at least 1 year. Additionally, the effect of the pulmonary band can be successfully and persistently relieved.

Background: Percutaneous balloon valvuloplasty has proven to be acutely effective in the treatment of congenital valvar aortic stenosis; however, the intermediate- and long-term effectiveness of the procedure remain to be documented., Methods and Results: To assess the intermediate-term effectiveness of balloon valvuloplasty, repeat catheterization was performed in 27 of 30 children 1.7 +/- 0.1 years after balloon valvuloplasty for congenital aortic stenosis (AS). In 33 children the peak AS gradient was reduced acutely by 55% from 77 +/- 4 to 35 +/- 3 mm Hg (p less than 0.001), and left ventricular systolic pressure was reduced from 176 +/- 4 to 138 +/- 4 mm Hg (p less than 0.001). Despite a technically adequate valvuloplasty procedure, three patients had inadequate relief of obstruction and required complex surgical intervention. Twenty-seven of the 30 patients available for late reevaluation (90%) enrolled in the follow-up study. The peak AS gradient remained significantly reduced compared with that present before valvuloplasty (29 +/- 3 versus 77 +/- 4 mm Hg, p less than 0.001). Furthermore, there was no difference in peak AS gradient at follow-up compared with that immediately after valvuloplasty. The greatest increase in gradient at reevaluation was 14 mm Hg. Twenty of 27 patients (74%) had no change in the degree of aortic insufficiency at follow-up compared with that present before valvuloplasty. At follow-up, 16 patients had no aortic insufficiency at all, and only two had moderate-to-severe (3-4+) insufficiency. Femoral artery injury was documented in four patients, three of whom were under 12 months of age at valvuloplasty., Conclusions: Balloon aortic valvuloplasty provides safe and effective intermediate-term gradient relief without early restenosis in children and adolescents with congenital AS.

A review is presented of the potential ways in which insulin resistance and hypertension may be linked. Although controversy exists as to the role insulin resistance and hyperinsulinemia play in the pathogenesis of hypertension, data are presented from both obese and nonobese subjects that strongly suggests that selective insulin resistance and hypertension are directly related. Because insulin resistance may be both tissue and pathway specific, it is possible that the degree to which insulin resistance is tissue specific determines whether hypertension will develop in specific individuals or animals.

Between 1986 and July 1990, balloon valvuloplasty was attempted in eight newborns (less than 28 days of age) with isolated critical aortic valve stenosis. Balloon valvuloplasty could not be successfully accomplished in any of the three infants presenting before 1989. Since March 1989, when improved catheter technology became available, all five neonates presenting with critical aortic stenosis were treated successfully by balloon valvuloplasty. A transumbilical approach was utilized in all four infants in whom umbilical artery access could be obtained. One newborn who was 25 days of age underwent transfemoral balloon valvuloplasty. Balloon valvuloplasty was immediately successful in all five newborns, as evidenced by a decrease in valve gradient and improvement in left ventricular function and cardiac output. Peak systolic gradient was reduced by 64% from 69 +/- 8 to 25 +/- 3 mm Hg (p = 0.005). Left ventricular systolic pressure decreased from 128 +/- 9 to 95 +/- 9 mm Hg (p = 0.02) and left ventricular end-diastolic pressure decreased from 20 +/- 2 to 11 +/- 1 mm Hg (p = 0.02). Moderate (2+) aortic regurgitation was documented in two infants after valvuloplasty. The time from first catheter insertion to valve dilation averaged 57 +/- 14 min (range 26 to 94) and the median length of the hospital stay was 4 days. With the use of recently available catheters, the transumbilical technique of balloon valvuloplasty can be performed quickly, safely and effectively in the newborn with critical aortic stenosis. It does not require general anesthesia, cardiopulmonary bypass or a left ventricular apical incision and it preserves the femoral arteries for future transcatheter intervention should significant aortic stenosis recur.

The acute hemodynamic effects of captopril were evaluated at cardiac catheterization in 16 children (age, 0.3-18 years) with cardiomyopathy. Twelve children had congestive cardiomyopathy, whereas four had restrictive cardiomyopathy. Hemodynamic measurements were obtained 30 and 60 minutes after the oral administration of captopril (0.5 mg/kg). Blood pressures were measured in the aorta, pulmonary artery, right atrium, and pulmonary capillary wedge position; cardiac outputs were measured by the thermodilution technique. Hemodynamic data could not be obtained after the administration of captopril in one child with congestive cardiomyopathy because of an immediate, severe hypotensive response. In 11 of 12 children with congestive cardiomyopathy, cardiac index increased by 22%, from 2.3 to 2.8 l/min/m2 (p less than 0.05), and stroke volume increased by 22%, from 23 to 28 ml/m2 (p less than 0.05). Systemic vascular resistance decreased from 32 to 21 units.m2 (p less than 0.01), but the mean aortic pressure did not change significantly. In contrast, four children with restrictive cardiomyopathy had no change in cardiac output after captopril, but there was a trend toward significant arterial hypotension (mean aortic pressure decreased from 78 to 59 mm Hg). Thus, captopril acutely reduced systemic vascular resistance and increased both cardiac output and stroke volume in children with congestive cardiomyopathy. In children with restrictive cardiomyopathy, however, captopril did not affect cardiac output, but it did decrease aortic pressure. These data indicate that captopril may benefit children with a congestive cardiomyopathy but that captopril probably should not be used in children with restrictive disease.