Surgical palliation of truncus arteriosus with mitral atresia and hypoplastic left ventricle

A rare case of truncus arteriosus associated with mitral valve atresia, hypoplastic left ventricle, and intact ventricular septum is reported. Successful medical management and surgical palliation of this defect is described. The possible embryology, pertinent hemodynamics, and clinical concerns with this unusual case are discussed.

One-lung Fontan operation: hemodynamics and surgical outcome

BACKGROUND

This study examined the results of a Fontan operation for patients with acquired atresia of one main branch pulmonary artery.

METHODS

The data for 7 patients identified as having a hypoplastic left pulmonary artery discontinuous from the right pulmonary artery were compared with those for 65 patients with continuous pulmonary arteries who consecutively underwent a completion Fontan procedure.

RESULTS

No significant differences were found preoperatively with respect to right atrial pressure, aortic saturation, ventricular end-diastolic pressure, pulmonary artery pressure, pulmonary blood flow, or pulmonary vascular resistance. In the first 24 postoperative hours, there were no significant differences in heart rate, urine output, systemic venous pressure, or pulmonary venous pressure. Also, data regarding hospitalization length, effusions, and mortality were similar between the two groups. Postoperative systemic arterial saturation was lower in the one-lung group. There were no early postoperative deaths in the one-lung group, and 5 of the 7 patients are long-term survivors.

CONCLUSIONS

A completion Fontan procedure can be successfully performed in patients with a hypoplastic and discontinuous left pulmonary artery, although postoperative systemic arterial saturation is not as high as in patients with continuous pulmonary arteries.

Comparison of patterns of pulmonary venous blood flow in the functional single ventricle heart after operative aortopulmonary shunt versus superior cavopulmonary shunt

In this study we investigated the patterns of pulmonary venous flow in children with functional single ventricles to obtain a better understanding of the determinants of transpulmonary blood flow. Sixty-eight patients with functional single ventricles and aortopulmonary shunt (n = 34, group I), or superior cavopulmonary connection (n = 34, group II) underwent transesophageal Doppler echocardiographic assessment of flow in the left upper pulmonary vein before undergoing the next stage of surgery. Twelve patients from group II also underwent simultaneous evaluation of superior vena caval flow. Biphasic forward pulmonary venous flow was noted in 62 patients in sinus rhythm (S wave in systole, D wave in diastole); in 6 patients with junctional rhythm, significant early systolic reversal of flow was present. Both the S- and D-wave velocity-time integrals (VTI) were greater in group I than in group II (S(VTI) 9.9 +/- 4.2 vs 8.0 +/- 2.6, p = 0.02; D(VTI) 8.0 +/- 3.5 vs 4.2 +/- 2.6, p <0.001). In both groups, pulmonary venous flow was predominantly systolic; however, the proportion of flow during ventricular systole was significantly greater in group II than in group I (S(VTI)/D(VTI) group II: 2.4 +/- 1.5; group I 1.4 +/- 0.5, p = 0.001; percent systolic fraction of pulmonary venous flow group II = 67%, group I = 56%, p <0.001). Analysis of superior vena caval flow in group II revealed a single predominant wave with onset at early systole and peak in late systole at a mean of 150 ms after the pulmonary venous S-wave peak. Our data suggest that ventricular systole (i.e., atrial relaxation, atrioventricular valve descent) asserts great influence on transpulmonary blood flow in the functional single ventricle.

Free and total insulin-like growth factor I (IGF-I), IGF-binding protein-1 (IGFBP-1), and IGFBP-3 and their relationships to the presence of diabetic retinopathy and glomerular hyperfiltration in insulin-dependent diabetes mellitus

The existing literature on serum insulin-like growth factor I (IGF-I) levels in insulin-dependent diabetes mellitus (IDDM) is conflicting. Free IGF-I may have greater physiological and clinical relevance than total IGF-I. Recently, a validated method has been developed to measure free IGF-I levels in the circulation. Serum free and total IGF-I, IGF-binding protein-1 (IGFBP-1), and IGFBP-3 levels were measured in 56 insulin-treated IDDM patients and 52 healthy sex- and age-matched controls. Diabetic retinopathy was established by direct fundoscopy. In 54 IDDM patients, the glomerular filtration rate (GFR) and effective renal plasma flow were calculated from the clearance rate of [125I]iothalamate and [131I]iodohippurate sodium. Fasting free IGF-I, total IGF-I, and IGFBP-3 levels were significantly lower in IDDM patients than in age- and sex-matched healthy controls (free IGF-I, P < 0.005; total IGF-I, P < 0.001; IGFBP-3, P = 0.001), whereas IGFBP-1 levels were higher (P < 0.001). In IDDM subjects, decreases in free IGF-I, total IGF-I, and IGFBP-3 levels with age were observed (free IGF-I, r = -0.27 and P = 0.05; total IGF-I, r = -0.52 and P < 0.001; IGFBP-3, r = -0.37 and P = 0.005). Free IGF-I was inversely related to fasting glucose in IDDM subjects (r = -0.35; P = 0.01), whereas the relationship between total IGF-I and fasting glucose did not reach significance (r = -0.27; P = 0.06). Age-adjusted free IGF-I levels were significantly higher (P < 0.05) in IDDM subjects with retinopathy than in subjects without retinopathy after adjustment for age. Total IGF-I and IGFBP-3 levels were positively related to GFR (total IGF-I, r = 0.35 and P < 0.05; IGFBP-3, r = 0.28 and P < 0.05). Both of these differences lost significance after adjustment for age. Free IGF-I, total IGF-I, and IGFBP-3 levels were lower and IGFBP-1 levels were higher in insulin-treated IDDM subjects compared to those in age- and sex-matched controls. Free IGF-I, total IGF-I, and IGFBP-3 levels decreased significantly with age in IDDM subjects. Age-adjusted free IGF-I levels in subjects with diabetic retinopathy were higher than those in subjects without diabetic retinopathy. Total IGF-I and IGFBP-3 levels were positively related to GFR in IDDM subjects, but these relations were lost after adjustment for age. Measurement of serum free IGF-I levels in IDDM subjects did not have clear advantages compared to that of total IGF-I, IGFBP-1, and IGFBP-3 levels. Serum IGF-I and IGFBPs reflect their tissue concentrations to a various degree. Consequently, extrapolations concerning the pathogenetic role of the IGF/IGFBP system in the development of diabetic complications at the tissue level remain speculative.

Late surgical fenestration for complications after the Fontan operation

BACKGROUND

Significant morbidity after Fontan operation results in either takedown, heart transplantation, or death. Initial creation of a fenestration results in less morbidity and mortality; however, the role of late creation of a fenestration in aiding patients manifesting morbidity after an initial nonfenestrated Fontan operation is unclear.

METHODS AND RESULTS

We reviewed our experience with late creation of a surgical fenestration in 9 patients (5.2 +/- 3.1 years old) exhibiting chronic effusions (n = 4) or protein-losing enteropathy (PLE) (n = 5) after lateral tunnel-type Fontan operation. Patients with effusions had creation via coronary punch of two or three 3-mm defects; patients with PLE had creation of a large, 5-mm defect. One child with effusions and multisystem organ failure before fenestration died 7 weeks after surgery secondary to low cardiac output; the other 3 had resolution of effusions within 4 to 6 weeks. Of the 5 with PLE, 3 had normalization of serum proteins and resolution of symptoms at 2 to 6 weeks. The 2 failures had arterial saturations > 89% after surgery. Follow-up was from 25 to 30 months. Spontaneous closure of defects occurred in all 3 with effusions. No return of symptoms was noted in 2; however, the third reaccumulated effusions and has undergone refenestration with a large defect. All 3 patients with PLE have remained asymptomatic with patency of the fenestration (4 to 5 mm on echocardiography) and arterial saturation < or = 85% for > 2 years.

CONCLUSIONS

Late surgical creation of fenestration results in resolution of morbidity after Fontan operation. Improvement is related to the degree of right-to-left shunt created.

Early effects of streptozotocin-induced diabetes on insulin-like growth factor-I in the kidneys of growth hormone-transgenic and growth hormone-deficient dwarf mice

BACKGROUND

The renal growth and hyperfiltration observed in humans and animals with early diabetes might be dependent on growth hormone (GH) and insulin-like growth factor (IGF)-I. The aim of this study was to investigate the early changes in kidney IGF-I in experimental diabetes in mice transgenic for bovine GH and in genetically GH-deficient Ames dwarf mice.

METHODS

At 2, 4 and 8 days after a single intraperitoneal injection with streptozotocin, animals were weighted, bled and killed; plasma was analyzed for glucose and IGF-I. IGF-I levels were determined in tissue from snap-frozen kidney and liver.

RESULTS

Body weight decreased significantly after the induction of diabetes. Kidney weight increased significantly in GH-transgenic, but not in normal or dwarf mice. Plasma IGF-I was significantly decreased at day 2 in GH-transgenic and normal mice, while liver IGF-I was increased at day 4 in all mice. Kidney IGF-I increased significantly in normal and GH-transgenic mice and was increased more than 3-fold at day 4 in GH-transgenic mice. In dwarf mice, no kidney IGF-I was detectable.

CONCLUSION

The diabetes-induced increase in renal IGF-I is dependent on the presence of GH. GH deficiency may protect diabetic animals from early changes in the kidney.

Tetralogy of Fallot with absent pulmonary valve: echocardiographic morphometric features of the right-sided structures and their relationship to presentation and outcome

Respiratory symptoms in tetralogy of Fallot with absent pulmonary valve are believed to be due to bronchial compression secondary to dilated pulmonary arteries; however, not all patients are born compromised. Echocardiographic morphometry of the right-sided structures was investigated to determine the possible relationship between anatomy and clinical presentation. Twenty-five patients were identified, and 15 had preoperative echocardiograms. Patients were divided into two groups: those with respiratory distress (group I, n = 9) and those without (group II, n = 6). No difference was noted in branch pulmonary artery diameters between groups; however, the pulmonary valve/ aortic valve ratio, reflecting the dimension of the narrowest pathway from the right ventricle, was larger in group I (0.74 +/- 0.15 versus 0.60 +/- 0.07, p < 0.05). Pulmonary valve diameter correlated with main and right pulmonary artery diameters. We conclude that patients with tetralogy of Fallot with absent pulmonary valve and respiratory compromise have a greater pulmonary valve/aortic valve ratio but do not have greater dilatation of proximal branch pulmonary arteries. This suggests that the pathophysiology is not due solely to compression of the bronchi but is also related to the blood flow dynamics in the pulmonary vessels.

Effect of surgical reconstruction on flow profiles in the aorta using magnetic resonance blood tagging

BACKGROUND

The aorta that has undergone an aorta-pulmonary artery anastomosis may not exhibit the same velocity profile as the nonreconstructed aorta, whose velocity profile is thought to be uniform across the vessel diameter (plug flow). This may have an impact on fluid dynamics and will alter Doppler flow calculations. Our objective was to determine the impact of surgical reconstruction on the velocity and flow profiles of the reconstructed ascending and descending aorta.

METHODS

Using a magnetic resonance imaging tagging technique that labels flowing blood (bolus tagging), we studied 22 patients (mean age, 8.6 +/- 4.7 years) who had had a Fontan procedure. A cine sequence labeled the blood and acquired the image after 20 ms in the middle of the ascending aorta and behind the left atrium in the descending aorta. The repetition time was 50 ms.

RESULTS

The reconstructed ascending aorta displayed a velocity profile skewed anteriorly, whereas in the nonreconstructed aorta, the velocity profile was flat. Reconstructed aortas also displayed flows that were higher anteriorly, took a longer time to reach maximum velocity, and were less like "plug" flow than the nonreconstructed aorta. The descending aorta, regardless of whether aortic reconstruction was present, displayed velocity profiles (at various phases of systole) skewed posteriorly.

CONCLUSIONS

The reconstructed aorta displays disturbed flow, and the velocities across the ascending aortic diameter are more varied than those in aortas without reconstruction and are skewed anteriorly. The descending aortic velocity profile in children is skewed posteriorly, regardless of whether aortic reconstruction is present. This information may help design and build a "better" aortic reconstruction.

The single ventricle heart in the fetus: accuracy of prenatal diagnosis and outcome

OBJECTIVES

The purpose of this study was to determine the diagnostic accuracy of fetal echocardiography in evaluating anatomic details of the single ventricle heart and the outcome of fetuses diagnosed with this anomaly.

STUDY DESIGN

This is a retrospective study of 57 fetuses in which the results of fetal echocardiography were compared with the diagnoses at postnatal echocardiography, and postnatal surgical outcome was reviewed.

RESULTS

Diagnostic accuracy was present in predicting morphology of the predominant ventricle, visceral situs, presence of pulmonary or aortic outflow tract obstruction, and presence of obstructed pulmonary venous outflow (sensitivity 100%). However, the ability to predict for a ductal dependent pulmonary circulation was poor (sensitivity 63%). Errors were made in the fetal assessment of ventricular size and viability such that in three cases, postnatal plans were altered toward a two-ventricular intervention. Of the 57 fetuses, intervention was elected in 37 (75%). Termination or nonintervention was elected in 14, and and 6 died before intervention. Of those operated on, 71% are presently alive after various stages of intervention.

CONCLUSIONS

Accurate diagnosis of the fetal single ventricle heart is possible, and outcome is improving. Caution must be used in judging ventricular size and in predicting ductal dependent pulmonary circulation.

Effect of long-acting somatostatin analog (Somatulin) on renal hyperfiltration in patients with IDDM

OBJECTIVE

To investigate whether long-acting somatostatin (SMS) can suppress renal hyperfiltration in patients with IDDM.

RESEARCH DESIGN AND METHODS

A double-blind, randomized treatment of nine patients with IDDM was used. Selection criteria were renal hyperfiltration (glomerular filtration rate [GFR] > or = 129 ml.min-1.1.73 m2) and absence of hypertension and macroalbuminuria. Treatment was either with a long-acting SMS analog (Somatulin, 30 mg) or with placebo, given by intramuscular injections every 10 days for 9 months. GFR, effective renal plasma flow (ERPF), IGF-I, and 24-h growth hormone (GH) profiles were used as evaluation parameters.

RESULTS

Five patients were randomized to Somatulin, four patients to placebo. One of the patients treated with Somatulin stopped after 3 months because of persistent abdominal discomfort after the injections. Somatulin treatment for 3 months lowered GFR and ERPF compared with placebo (P < 0.05). After 9 months, the differences were no longer significant. After 3 months, IGF-I concentrations were decreased in all Somatulin-treated patients. GH secretion tended to increase in the placebo group.

CONCLUSIONS

The administration of long-acting Somatulin to patients with IDDM and renal hyperfiltration leads to only a temporary reduction of ERPF/GFR.

Pulmonary AV malformations after superior cavopulmonary connection: resolution after inclusion of hepatic veins in the pulmonary circulation

BACKGROUND

A high incidence of pulmonary arteriovenous malformations (PAVMs) has been reported in patients who have polysplenia and congenital heart disease after superior cavopulmonary anastomosis. Interruption of hepatic venous return to the pulmonary circulation is believed to potentiate the development of PAVMs. Surgical inclusion of hepatic flow in the pulmonary circulation may result in their resolution.

METHODS

We reviewed 3 patients with congenital heart disease and polysplenia in whom PAVMs developed and who had subsequent hepatic vein inclusion in the pulmonary circulation.

RESULTS

Patients underwent superior cavopulmonary connection at a median age of 8 months. The PAVMs were diagnosed at a median duration of 8 months after operation (arterial saturation <75% in room air). Hepatic venous flow was included in the pulmonary circulation at operation. Resolution of PAVMs occurred at a median duration of 7 months after operation (arterial saturation >90% in room air).

CONCLUSIONS

Surgical inclusion of hepatic venous blood in the pulmonary circulation results in the resolution of PAVMs. Electively associating the hepatic veins with the pulmonary vasculature may prevent the development of PAVMs in patients who are at risk.

Effect of BMI, insulin dose and number of injections on glycaemic control in insulin-using diabetic patients. Studygroup Diabetes Rijnmond (SDR)

BACKGROUND

Strict glucose control is essential to the prevention of diabetic complications. The level of glycaemic control in insulin-treated patients with diabetes mellitus (DM) in a routine clinical setting is not known.

METHODS

In a cross-sectional survey comprising 8 hospitals in the Rijnmond area, The Netherlands, age, body mass index (BMI), insulin dose, number of injections, and HbA1c were scored in 712 patients with insulin-dependent DM (IDDM) and 462 patients with non-insulin-dependent DM (NIDDM).

RESULTS

In IDDM and NIDDM patients, respectively, age (mean +/- SD) was 40 +/- 17 and 65 +/- 12 years, BMI was 24.1 +/- 3.5 and 27.3 +/- 4.1 kg/m2, daily insulin dose was 49 +/- 18 and 44 +/- 18 U (P < 0.001). Intensive therapy (> or = 4 injections or continuous subcutaneous insulin infusion) was used in 59% of IDDM and 13% of NIDDM patients. HbA1c below the upper normal limit was achieved in 11% of the patients, and within 20% above the upper normal limit in 37%. Obesity was positively associated with HbA1c in NIDDM patients (P < 0.01). A higher insulin dose was associated with higher HbA1c in both IDDM and NIDDM patients (P < 0.01).

CONCLUSIONS

Good glycaemic control was established in 37% of our patients. Intensive insulin treatment and higher insulin dose did not improve glucose regulation. Obesity is a risk factor for poor glycaemic control.

Cerebral oxygenation during cardiopulmonary bypass in children

OBJECTIVE

Previous work has found cerebral oxygen extraction to decrease during hypothermic cardiopulmonary bypass in children. To elucidate cardiopulmonary bypass factors controlling cerebral oxygen extraction, we examined the effect of perfusate temperature, pump flow rate, and hematocrit value on cerebral hemoglobin-oxygen saturation as measured by near infrared spectroscopy.

METHODS

Forty children less than 7 years of age scheduled for cardiac operations with continuous cardiopulmonary bypass were randomly assigned to warm bypass, hypothermic bypass, hypothermic low-flow bypass, or hypothermic low-hematocrit bypass. For warm bypass, arterial perfusate was 37 degrees C, hematocrit value 23%, and pump flow 150 ml/kg per minute. Hypothermic bypass differed from warm bypass only in initial perfusate temperature (22 degrees C); hypothermic low-flow bypass and low-hematocrit bypass differed from hypothermic bypass only in pump flow (75 ml/kg per minute) and hematocrit value (16%), respectively. Cerebral oxygen saturation was recorded before bypass (baseline), during bypass, and for 15 minutes after bypass had been discontinued.

RESULTS

In the warm bypass group, cerebral oxygen saturation remained at baseline levels during and after bypass. In the hypothermic bypass group, cerebral oxygen saturation increased 20% +/- 2% during bypass cooling (p < 0.001), returned to baseline during bypass rewarming, and remained at baseline after bypass. In the hypothermic low-flow and hypothermic low-hematocrit bypass groups, cerebral oxygen saturation remained at baseline levels during bypass but increased 6% +/- 2% (p = 0.05) and 10% +/- 2% (p < 0.03), respectively, after bypass was discontinued.

CONCLUSIONS

In children, cortical oxygen extraction is maintained during warm cardiopulmonary bypass at full flow and moderate hemodilution. Bypass cooling can decrease cortical oxygen extraction but requires a certain pump flow and hematocrit value to do so. Low-hematocrit hypothermic bypass and low-flow hypothermic bypass can also alter cortical oxygen extraction after discontinuation of cardiopulmonary bypass.

Hypertriglyceridemia enhances monocyte binding to endothelial cells in NIDDM

OBJECTIVE

The mechanisms by which diabetes leads to rapidly progressive atherosclerosis are not fully understood. Adherence of monocytes to the arterial wall is an early event in the development of atherosclerotic lesions.

RESEARCH DESIGN AND METHODS

The binding of freshly isolated monocytes from patients with NIDDM, IDDM, and healthy control subjects to a monolayer of endothelial cells obtained from human umbilical vein was investigated.

RESULTS

Endothelial adherence of monocytes from normolipidemic patients with IDDM (15.8 +/- 4.5%) or NIDDM (16.9 +/- 4.6%) was comparable to that of monocytes from a control population (15.3 +/- 3.5%). In patients with NIDDM with a serum triglyceride concentration > 2.5 mmol/l, the percentage of cells that adhere to endothelial cells in vitro was significantly increased (23.3 +/- 3.1%). Glycemic control did not correlate with monocyte adherence. The presence of symptomatic atherosclerotic disease, age, or sex was not associated with a change in monocyte binding in vitro.

CONCLUSIONS

The results suggest that in NIDDM hypertriglyceridemia should be treated to reduce the high risk for atherosclerosis.

Morphometric analysis of unbalanced common atrioventricular canal using two-dimensional echocardiography

OBJECTIVES

This study was designed to define morphometric echocardiographic variables of unbalanced common atrioventricular canal (CAVC) that could aid in appropriate referral for surgical repair.

BACKGROUND

Unbalanced CAVC has a high surgical mortality rate. This may be secondary to inappropriate referral of some patients for two-ventricle repair (closure of septal defects) instead of single-ventricle repair (Norwood palliation and Fontan operation).

METHODS

The echocardiograms of 103 patients with CAVC were retrospectively reviewed. In the subcostal left anterior oblique view, the area of the atrioventricular (AV) valve aportioned over each ventricle was measured, and an AV valve index (AVVI) was calculated as left/right valve area. The ventricular cavity ratio between the two ventricles was estimated as left ventricular length times width divided by right ventricular length times width. These variables were correlated with surgical referral and outcome.

RESULTS

Patients previously categorized as having balanced CAVC all had AVVI > 0.67 (n = 77). Of the patients with unbalanced CAVC (n = 26), 11 had ductal-dependent circulation and underwent Norwood palliation (AVVI 0.21 +/- 0.13, mean +/- SD), and 15 had two-ventricle repair (AVVI 0.51 +/- 0.12, p < 0.0001). Of these 15 patients, 9 have survived, with no difference in mean AVVI between survivors and nonsurvivors (0.52 +/- 0.11 versus 0.49 +/- 0.13, p = 0.72). For all 103 patients, AVVI correlated with ventricular cavity ratio. However, of the unbalanced CAVC group who underwent two-ventricle repair, three nonsurvivors had a discrepancy between AVVI and ventricular cavity ratio (low AVVI but normal ventricular size). A large ventricular septal defect was present in all six nonsurvivors but in only four of nine survivors (p < 0.05).

CONCLUSIONS

Echocardiographic morphometry is useful in defining unbalance in CAVC. If AVVI is < 0.67 in the presence of a large ventricular septal defect, a single-ventricle approach to repair should be considered.

Early reduction of the volume work of the single ventricle: the hemi-Fontan operation

BACKGROUND

In hearts with a functional single ventricle, cavity volume and myocardial muscle mass increase as a consequence of the excessive volume work associated with parallel pulmonary and systemic circulations. The hemi-Fontan operation was conceived as a means of accomplishing early reduction of the volume work of the single ventricle.

METHODS

All patients presenting in infancy with single-ventricle physiology were managed by early hemi-Fontan operation in anticipation of a subsequent completion Fontan operation. Between May 1989 and August 1995, 400 patients less than 2 years of age underwent hemi-Fontan operations. Mean age at operation was 8.5 months (range, 2 months to 24 months). The hemi-Fontan operation included association of superior vena(e) cava(e) with the branch pulmonary arteries, augmentation of the central pulmonary arteries, occlusion of the inflow of the superior vena cava into the right atrium, and elimination of other sources of pulmonary blood flow.

RESULTS

Operative mortality ( < 30 days) was 31 of 400 patients (7.8%). For the last 200 patients, operative mortality was 8 of 200 (4.0%). Younger age at operation was not an independent risk factor for operative mortality. Urgent operation in the presence of a hemodynamic burden requiring concomitant procedures was associated with increased mortality.

CONCLUSIONS

The hemi-Fontan operation can be accomplished with low operative mortality in young patients, achieving early reduction of the volume work of the single-ventricle heart.

Growth hormone responses to growth hormone-releasing hormone and clonidine in patients with type I diabetes and in normal controls: effect of age, body mass index and sex

OBJECTIVE

Increased plasma concentrations of GH and increased GH responses to provocative stimuli are reported in patients with poorly controlled type I diabetes and are suggested to be related to complications. Our aim was to investigate GH concentrations in moderately controlled patients.

PATIENTS AND MEASUREMENTS

We have investigated IGF-I concentrations and fasting GH concentrations and the response to 1 microgram/kg body weight GH-releasing hormone (GHRH) intravenously and/or to 150 micrograms clonidine intravenously in 77 moderately controlled patients with type I diabetes and in 46 healthy controls.

RESULTS

Median HbA1c in the patients was 8.5% (upper level of normal 6.3%). Fasting GH and GH concentrations after the administration of GHRH were not significantly different in patients with type I diabetes compared with normal controls. Fasting and stimulated GH concentrations after the administration of clonidine were significantly higher in the patients, but this could be explained by their lower age and body mass index compared with controls. In controls but not in patients there was a negative correlation between GH and glucose concentrations. IGF-I was significantly lower in patients with diabetes than in controls, even after correction for age, body mass index and sex.

CONCLUSIONS

Patients with moderately controlled type I diabetes mellitus have normal baseline and stimulated GH concentrations after the administration of GHRH or clonidine compared with healthy controls, when corrected for age, body mass index and sex. However, these 'normal' GH concentrations must be considered inappropriately high in view of the hyperglycaemia in these patients. The low plasma IGF-I concentrations might be responsible for the GH over-production.

Doppler echocardiographic analysis of flow in the ductus arteriosus of infants with hypoplastic left heart syndrome: relationship of flow patterns to systemic oxygenation and size of interatrial communication

Excessive pulmonary overcirculation related to imbalance in the pulmonary/systemic vascular resistance ratio contributes to hemodynamic instability in infants with the hypoplastic left heart syndrome. Because the ductus arteriosus bridges the two vascular circuits in this lesion, we studied the Doppler echocardiographic flow patterns in the ductus arteriosus of 50 infants with hypoplastic left heart syndrome to investigate their relationship to the degree of pulmonary blood flow as measured by simultaneously obtained levels of partial pressure of oxygen in arterial blood. The degree of restriction to pulmonary venous egress as determined by size of the interatrial communication was also correlated with ductal flow patterns and partial pressure of oxygen in arterial blood. Biphasic flow was noted in all infants. Mean peak velocity of antegrade flow (pulmonary artery to aorta) was greater than that of retrograde flow (aorta to pulmonary artery) (131 +/- 45 cm/sec versus 54 +/- 15 cm/sec; p < 0.001), mean time of retrograde flow was greater than that of antegrade flow (246 +/- 60 msec versus 174 +/- 28 msec; p < 0.001), and mean velocity-time integral of antegrade flow was greater than that of retrograde flow (13.3 +/- 4.8 cm versus 6.3 +/- 3.4 cm; p < 0.001). The ratio of velocity-time integral of retrograde flow/antegrade flow (a volumetric estimate of diastolic reversal into the pulmonary vascular bed indexed to systemic output) correlated extremely well with partial pressure of oxygen in arterial blood (r = 0.91; p < 0.0001). Categoric size of the interatrial communication (none, n = 2; small [<2 mm], n = 9; moderate [3 to 4 mm], n = 23; and large [>4 mm], n = 16) correlated with partial pressure of oxygen in arterial blood (r = 0.82; p < 0.001); the smaller the interatrial communication the lower the partial pressure of oxygen in arterial blood and velocity-time integral ratio of retrograde/antegrade flow. Doppler flow patterns in the ductus arteriosus of infants with hypoplastic left heart syndrome are reflective of the resistance ratio between the pulmonary and systemic vascular circuits and may be helpful in monitoring the hemodynamics of these infants.

Morphology of the ventricular septal defect in two types of interrupted aortic arch

Whether coarctation or interruption (IAA) of the aorta, ostensibly similar in morphology (and management), result from the same or different developmental errors can be inferred by examining the pattern of associated anomalies. Among the most common associated lesions, especially in IAA, is ventricular septal defect (VSD). Although muscular and perimembranous VSDs are the most common in aortic coarctation, the prevalence of various VSD morphologies in IAA has not been examined in as much detail. As part of the recent prospective multiinstitutional study of IAA conducted by the Congenital Heart Surgeons Society, 53 echocardiographic studies were reviewed; 42 of 45 patients with type B IAA had VSDs involving maldevelopment of the outflow region. In type A IAA, a significantly lower percentage (4/8) had this kind of VSD. Therefore the mechanism of development of type B IAA is likely to be different from that of type A IAA.

Protein-losing enteropathy after Fontan operation: resolution after baffle fenestration

A 4-year-old child with hypoplastic left heart syndrome and a 6-year-old child with tricuspid atresia had both undergone staged reconstructive operations culminating in a Fontan operation. Peripheral edema, ascites, and hypoalbuminemia refractory to dietary manipulation and steroid therapy developed in both patients. After hemodynamic assessment, each child underwent surgical creation of a 4.8-mm fenestration in the previously placed baffle that separated the systemic venous pathway from the pulmonary venous atrium. Peripheral edema and ascites promptly resolved and serum protein levels normalized within 2 weeks after operation. Systemic arterial saturation is 86% in each child, and both children remain clinically well with no evidence of protein-losing enteropathy on normal diets and without specific medical therapy.

Avoidance of subaortic obstruction in staged management of single ventricle

BACKGROUND

Subaortic obstruction is a frequent accompaniment of single-ventricle anatomy. Most often, the aorta arises from an outflow chamber that is connected to the single ventricle by a bulboventricular foramen or ventricular septal defect. This connection may be restrictive of flow at birth, or may become obstructive after surgical procedures that reduce the volume work of the ventricle. Subaortic obstruction is recognized as a risk factor for reconstructive surgical procedures for single ventricle.

METHODS

To prevent the consequences of subaortic obstruction, we have routinely amalgamated the proximal main pulmonary artery with the ascending aorta and arch early in the management of these patients. From September 1990 through September 1994, 29 neonates and infants with single ventricle and established or potential subaortic obstruction underwent staged reconstructive surgical procedures. The initial operation in the newborn period was a Norwood procedure (18 patients) or a pulmonary artery band (5 patients). All survivors underwent a hemi-Fontan procedure at approximately 6 months.

RESULTS

Eighteen patients have undergone a completion Fontan operation with no deaths. Five await completion Fontan. None has subaortic obstruction, and none has pulmonary valve insufficiency that is graded more than mild.

CONCLUSIONS

Early association of the proximal main pulmonary artery with the ascending aorta appears to obviate the risks and complications associated with subaortic obstruction in patients with single ventricle.

Acute changes in left ventricular geometry after volume reduction operation

BACKGROUND

After surgical removal of a volume load, regression of myocardial mass proceeds slowly relative to diminution in ventricular cavity size, resulting in increased wall thickness and decreased cavity dimensions, which may affect the filling properties and performance of the heart. We investigated the acute changes in ventricular geometry that occur after the Fontan operation and hemi-Fontan operation for tricuspid atresia, and compared them with closure of a ventricular septal defect in a two-ventricle heart.

METHODS

We reviewed the results of echocardiography performed before and 8 +/- 7 days after (1) Fontan operation for tricuspid atresia (n = 9), (2) hemi-Fontan operation for tricuspid atresia (n = 10), and (3) closure of a ventricular septal defect (n = 13). Measurements were made from images of the left ventricle at end-diastole: (1) apical, septal, and posterior wall thickness; and (2) long- and short-axis cavity diameters, cross-sectional areas, and ventricular volume. Posterior wall thickness to cavity dimension ratio was calculated.

RESULTS

Wall thickness increased in all groups, with the greatest degree of increase after the Fontan operation. Cavity measures decreased most dramatically after the Fontan operation, with less dramatic and equivalent changes noted after the hemi-Fontan operation and ventricular septal defect closure. Posterior wall thickness to cavity diameter ratios were equivalent in all before operation, increased after operation, and were greatest after the Fontan operation.

CONCLUSIONS

Changes in ventricular geometry identified as an increase in wall thickness and a decrease in cavity dimension are most dramatic after the Fontan operation. Changes seen after the hemi-Fontan operation are of a milder degree, which may in part explain the excellent clinical course after this operation.

Results of Norwood's operation for lesions other than hypoplastic left heart syndrome

Norwood's operation provides satisfactory palliation for neonates with hypoplastic left heart syndrome. The dominant physiologic features of hypoplastic left heart syndrome, ductal dependency of the systemic circulation and parallel pulmonary and systemic circulations, are shared by a multitude of other less common congenital heart malformations. Theoretically, these should be equally amenable to palliation by Norwood's operation. Between January 1990 and June 1994, 60 neonates with malformations other than hypoplastic left heart syndrome underwent initial surgical palliation by Norwood's procedure. Diagnoses included single left ventricle with levo-transposition of the great arteries (12); critical aortic stenosis (8); complex double-outlet right ventricle (8); interrupted aortic arch with ventricular septal defect and subaortic stenosis (7); ventricular septal defect, subaortic stenosis, and coarctation of the aorta (7); aortic atresia with large ventricular septal defect (6); tricuspid atresia with transposition of the great arteries (6); heterotaxy syndrome with subaortic obstruction (3); and other (3). There were 10 hospital deaths and 50 survivors (83% survival). After the introduction of inspired carbon dioxide therapy into the postoperative management protocol (1991), 42 of 47 patients survived (89% survival). Mortality was independent of diagnosis and essentially the same as that for hypoplastic left heart syndrome. With minor technical modifications, Norwood's operation provides satisfactory initial palliation for a wide variety of malformations characterized by ductal dependency of the systemic circulation in anticipation of either a Fontan procedure or a biventricular repair.

Interrupted aortic arch. Impact of subaortic stenosis on management and outcome

Interrupted aortic arch (IAA) is often related developmentally to subaortic obstruction (SAO). When severe, SAO must be addressed in surgical management of IAA. From 1990 to 1993, 25 neonates presented for initial surgical management of IAA complexes. Associated lesions were ventricular septal defect (VSD) with or without atrial septal defect (19 patients), truncus arteriosus (3 patients), tricuspid atresia with transposition of the great arteries (1 patient), aortic atresia with VSD (1 patient), and d-transposition of the great arteries with VSD (1 patient). Overall hospital mortality was 20% (five deaths). One death was related to sepsis and two to sudden hemodynamic decompensation (a 2-kg premature infant after arch repair and VSD closure and a neonate with IAA-truncus arteriosus after arch repair and truncus repair with aortic root replacement). Two deaths were related to low cardiac output in patients with severe subaortic narrowing (< 3 mm by two-dimensional echocardiography), which was not addressed surgically. Of 10 additional patients judged preoperatively to have severe SAO, 1 underwent resection of the infundibular septum together with VSD closure and arch reconstruction, and 9 underwent a modification of Norwood's operation with arch reconstruction and proximal pulmonary artery to aortic anastomosis (7 with systemic to pulmonary artery shunts and 2 with right ventricle to pulmonary artery outflow tract reconstruction). One patient died 2 months after surgery of staphylococcal sepsis. All 9 others were discharged well. Subaortic narrowing is a physiologically important element of IAA complexes. When SAO is severe, satisfactory initial palliation can be achieved by a modification of Norwood's operation.

Early changes in ventricular septal defect size and ventricular geometry in the single left ventricle after volume-unloading surgery

OBJECTIVES

This study investigated the phenomenon of, and the relation between, alterations in ventricular geometry after acute surgical volume unloading of the ventricle and the development of subaortic stenosis in patients with a single ventricle and ventricular septal defect-dependent systemic flow.

BACKGROUND

Subaortic outflow obstruction has been observed to occur in patients with a single left ventricle after placement of a pulmonary artery band. The timing and etiology of this phenomenon are not well defined.

METHODS

The preoperative and postoperative echocardiograms of 18 patients 14.9 +/- 22.8 months old (mean +/- SD) with a diagnosis of single left ventricle who underwent pulmonary artery banding or cavopulmonary connection were reviewed. Postoperative studies were performed a mean of 7.0 +/- 6.5 days after operation. The ventricular septal defect diameter was measured in two orthogonal views and the area calculated using the formula for an ellipse. Interventricular septal and posterior wall thickness and left ventricular diameter and length were also measured.

RESULTS

Mean ventricular septal defect area indexed to body surface area diminished by 36 +/- 23% (3.1 +/- 2.7 to 2.0 +/- 1.8 cm2/m2, p < 0.01). Mean interventricular septal and posterior wall thickness increased significantly, and left ventricular diameter and length decreased significantly. A greater diminution in ventricular septal defect area was noted after cavopulmonary connection (41 +/- 19%, p < 0.01) than after pulmonary artery banding (25 +/- 28%, p = 0.22).

CONCLUSIONS

In the single left ventricle, diminution in ventricular septal defect size occurs early and is related to an acute alteration in ventricular geometry that accompanies the decrease in ventricular volume. Ventricular septal defect diminution was greater after volume unloading of the ventricle after cavopulmonary connection than after pulmonary artery banding.