Evolution of surgical trends in congenital heart disease: a population based study

The aim of this study was to establish surgical trends in patients with congenital heart disease operated on between 1947 and 1997 in a population based study. All patients diagnosed as having congenital heart disease, born in Malta up to 1995 inclusive and operated for congenital heart disease up to 1997 inclusive were included. Analysis was carried out for lesions operated, age at surgery, operative centre and mortality rates, in the setting of a regional hospital providing congenital heart disease diagnostic and follow-up services for all Malta. Increasingly more operations for cardiac malformations are being carried out, with a progressively higher proportion of operations performed on complex conditions (P<0.001), at an ever younger age (P<0.001), and with a declining perioperative mortality (P<0.001). For the period 1990-1994, 4.2 operations for congenital heart disease/1000 live births were required. Factors which may increase or decrease this rate in future are discussed, along with costs of surgery. Surgery for congenital heart disease has become progressively more aggressive and safer since this method of treatment for these malformations was initiated, but this has occurred at a significant financial cost.

Therapeutic efficacy of multiple intravenous infusions of anti-tumor necrosis factor alpha monoclonal antibody combined with low-dose weekly methotrexate in rheumatoid arthritis

OBJECTIVE

To evaluate the efficacy, pharmacokinetics, immunogenicity, and safety of multiple infusions of a chimeric monoclonal anti-tumor necrosis factor alpha antibody (cA2) (infliximab; Remicade, Centocor, Malvern, PA) given alone or in combination with low-dose methotrexate (MTX) in rheumatoid arthritis (RA) patients.

METHODS

In a 26-week, double-blind, placebo-controlled, multicenter trial, 101 patients with active RA exhibiting an incomplete response or flare of disease activity while receiving low-dose MTX were randomized to 1 of 7 groups of 14-15 patients each. The patients received either intravenous cA2 at 1, 3, or 10 mg/kg, with or without MTX 7.5 mg/week, or intravenous placebo plus MTX 7.5 mg/week at weeks 0, 2, 6, 10, and 14 and were followed up through week 26.

RESULTS

Approximately 60% of patients receiving cA2 at 3 or 10 mg/kg with or without MTX achieved the 20% Paulus criteria for response to treatment, for a median duration of 10.4 to >18.1 weeks (P < 0.001 versus placebo). Patients receiving cA2 at 1 mg/kg without MTX became unresponsive to repeated infusions of cA2 (median duration 2.6 weeks; P=0.126 versus placebo). However, coadministration of cA2 at 1 mg/kg with MTX appeared to be synergistic, prolonging the duration of the 20% response in >60% of patients to a median of 16.5 weeks (P < 0.001 versus placebo; P=0.006 versus no MTX) and the 50% response to 12.2 weeks (P < 0.001 versus placebo; P=0.002 versus no MTX). Patients receiving placebo infusions plus suboptimal low-dose MTX continued to have active disease, with a Paulus response lasting a median of 0 weeks. A 70-90% reduction in the swollen joint count, tender joint count, and C-reactive protein level was maintained for the entire 26 weeks in patients receiving 10 mg/kg of cA2 with MTX. In general, treatment was well tolerated and stable blood levels of cA2 were achieved in all groups, except for the group receiving 1 mg/kg of cA2 alone, at which dosage antibodies to cA2 were observed in approximately 50% of the patients.

CONCLUSION

Multiple infusions of cA2 were effective and well tolerated, with the best results occurring at 3 and 10 mg/kg either alone or in combination with MTX in approximately 60% of patients with active RA despite therapy with low-dose MTX. When cA2 at 1 mg/kg was given with low-dose MTX, synergy was observed. The results of the trial provide a strategy for further evaluation of the efficacy and safety of longer-term treatment with cA2.

Anomalous coronary artery with tetralogy of Fallot and aortopulmonary window

Anomalous origin of the left main coronary artery from the pulmonary artery is rarely associated with other conditions. We report the case of an infant born with tetralogy of Fallot and aortopulmonary window who at the time of surgical repair was found to have an anomalous left main coronary artery originating from the right pulmonary artery.

Changes in leucocyte counts and soluble intercellular adhesion molecule-1 and E-selectin during cardiopulmonary bypass in children

A consequence of cardiopulmonary bypass (CPB) in young children is postoperative capillary leak and associated pulmonary dysfunction. Neutrophils sequester in the lungs and may contribute to functional endothelial damage. The endothelial adhesion molecules, E-selectin and intercellular adhesion molecule-1 (ICAM-1), mediate sequential steps in adhesion by binding to leucocyte ligands. Circulating forms of these proteins have been identified. We studied changes in the plasma concentrations of soluble E-selectin and soluble ICAM-1 using fixed phase immunoassays, and associated leucocyte counts in 10 paediatric patients undergoing CPB. Concentrations of soluble L-selectin and soluble ICAM-1 consistently fell during CPB from preoperative levels of 89 +/- 17 ng/ml (mean +/- 2SEM) and 218 + 61 ng/ml, respectively, to 39 +/- 7 ng/ml and 84 +/- 24 ng/ml, respectively at the beginning of maximum hypothermia. The haemodilution that occurred during CPB largely explained this fall, but not the more marked decrease in white cell counts that also occurred over this period (6.7 +/- 1.1 to 1.7 +/- 0.5 x 10(9)/l) which may reflect increased leucocyte sequestration. By 24 h postoperatively, levels of both soluble adhesion molecules approached preoperative concentrations, as did lymphocyte counts. In marked contrast, neutrophil counts rose appreciably towards the end of CPB, and continued to rise to a maximum of 10.9 +/- 3.1 x 10(9)/l during the immediate postoperative period and remained at these elevated levels 24 h later. Major consistent changes in circulating leucocyte numbers which occur early in cardiopulmonary bypass may reflect changes in adhesion to the endothelium and consequent sequestration. Alterations in the levels of soluble adhesion proteins may influence these processes.

Therapeutic efficacy of multiple intravenous infusions of anti-tumor necrosis factor alpha monoclonal antibody combined with low-dose weekly methotrexate in rheumatoid arthritis

OBJECTIVE

To evaluate the efficacy, pharmacokinetics, immunogenicity, and safety of multiple infusions of a chimeric monoclonal anti-tumor necrosis factor alpha antibody (cA2) (infliximab; Remicade, Centocor, Malvern, PA) given alone or in combination with low-dose methotrexate (MTX) in rheumatoid arthritis (RA) patients.

METHODS

In a 26-week, double-blind, placebo-controlled, multicenter trial, 101 patients with active RA exhibiting an incomplete response or flare of disease activity while receiving low-dose MTX were randomized to 1 of 7 groups of 14-15 patients each. The patients received either intravenous cA2 at 1, 3, or 10 mg/kg, with or without MTX 7.5 mg/week, or intravenous placebo plus MTX 7.5 mg/week at weeks 0, 2, 6, 10, and 14 and were followed up through week 26.

RESULTS

Approximately 60% of patients receiving cA2 at 3 or 10 mg/kg with or without MTX achieved the 20% Paulus criteria for response to treatment, for a median duration of 10.4 to >18.1 weeks (P < 0.001 versus placebo). Patients receiving cA2 at 1 mg/kg without MTX became unresponsive to repeated infusions of cA2 (median duration 2.6 weeks; P=0.126 versus placebo). However, coadministration of cA2 at 1 mg/kg with MTX appeared to be synergistic, prolonging the duration of the 20% response in >60% of patients to a median of 16.5 weeks (P < 0.001 versus placebo; P=0.006 versus no MTX) and the 50% response to 12.2 weeks (P < 0.001 versus placebo; P=0.002 versus no MTX). Patients receiving placebo infusions plus suboptimal low-dose MTX continued to have active disease, with a Paulus response lasting a median of 0 weeks. A 70-90% reduction in the swollen joint count, tender joint count, and C-reactive protein level was maintained for the entire 26 weeks in patients receiving 10 mg/kg of cA2 with MTX. In general, treatment was well tolerated and stable blood levels of cA2 were achieved in all groups, except for the group receiving 1 mg/kg of cA2 alone, at which dosage antibodies to cA2 were observed in approximately 50% of the patients.

CONCLUSION

Multiple infusions of cA2 were effective and well tolerated, with the best results occurring at 3 and 10 mg/kg either alone or in combination with MTX in approximately 60% of patients with active RA despite therapy with low-dose MTX. When cA2 at 1 mg/kg was given with low-dose MTX, synergy was observed. The results of the trial provide a strategy for further evaluation of the efficacy and safety of longer-term treatment with cA2.

Expression of Bcl-2 in human epithelial tumor (HeLa) cells enhances clonogenic survival following exposure to 5-fluoro-2'-deoxyuridine or staurosporine, but not following exposure to etoposide or doxorubicin

A reduced capacity for apoptosis induction is considered to play a significant role both in the development of malignancy and in tumor cell resistance to chemotherapeutic drugs. The Bcl-2 oncoprotein inhibits apoptosis induced by antitumor agents at a point downstream of drug-target interactions. Stable expression of Bcl-2 in the human epithelial tumor (HeLa) cell line results in inhibition of apoptosis following exposure to the topoisomerase II poison, etoposide. However, Bcl-2 is unable to enhance clonogenic survival as a result of alternate pathways to reproductive death induced by the drug.

PURPOSE

The purpose of this study was to further investigate the role of Bcl-2 in human epithelial tumor cell drug resistance using 5-fluoro-2'-deoxyuridine, staurosporine, and doxorubicin, in addition to etoposide.

METHODS

The ability of Bcl-2 to enhance clonogenic cell survival was studied by colony-forming assays, while delay of cell death induction was assessed by trypan blue viability measurements. The proportion of apoptotic cells was measured by morphological criteria, as well as detection of apoptotic DNA fragmentation using the terminal deoxynucleotidyl transferase assay.

RESULTS

Despite profound inhibition to loss of plasma membrane integrity for all agents tested, Bcl-2 was only able to significantly increase clonogenic survival following exposure to 5-fluoro-2'-deoxyuridine and staurosporine, but not following exposure to etoposide or doxorubicin. Furthermore, the time-course of apoptosis induction following exposure of HeLa cells to equitoxic concentrations of staurosporine and etoposide was profoundly different.

CONCLUSIONS

These results indicate that Bcl-2 enhances clonogenic survival of human epithelial tumor cells in an agent-specific fashion, which may be determined by the initial cytotoxic lesion induced by a particular drug.

Primary arterial switch operation for transposition of the great arteries with intact ventricular septum in infants older than 21 days

OBJECTIVES

The aim of this study was to assess the surgical outcome of the primary arterial switch operation (ASO) in infants 3 weeks to 2 months old.

BACKGROUND

The surgical management of transposition of the great arteries and intact ventricular septum (TGA/IVS) beyond 2 to 3 weeks of age is controversial. Concern that regression of the left ventricular (LV) myocardial mass will render the left ventricle incapable of coping with the acutely increased work of systemic perfusion has been considered a contraindication to a primary ASO.

METHODS

We used retrospective analysis of 37 patients 3 weeks to 2 months old and 156 patients <3 weeks old who underwent primary ASO with TGA/IVS to determine the surgical outcomes.

RESULTS

Between January 1990 and December 1996, primary ASO was performed in 37 patients 21 to 61 days old (late ASO group) and 156 patients <21 days old (early ASO group) with TGA/IVS. One (2.7%, 95% confidence interval [CI] 0.07% to 14.2%) of 37 patients and 13 (8.3%, 95% CI 4.5% to 13.8%) of 156 patients died. One late death occurred in each group. Mechanical LV support was required in 1 (2.7%, 95% CI 0.07% to 14.2%) of 37 late ASO and 6 (3.8%, 95% CI 1.4% to 8.2%) of 156 early ASO group patients postoperatively. Neither death nor the need for mechanical LV support in the late ASO group patients could be attributed to LV failure. In the late ASO group, age, LV geometry, LV mass index, LV posterior wall thickness index, LV volume index, LV mass/volume ratio, patent arterial duct or pattern of coronary anatomy did not predict death, duration of postoperative ventilation or inotropic support or time in intensive care. Moreover, there was no difference in duration of ventilation, duration of inotropic support or the time spent in intensive care in comparison to a random sample of 37 neonates from the early ASO group.

CONCLUSIONS

Primary ASO may be appropriate treatment for infants with TGA/IVS < or = 2 months old, regardless of preoperative echocardiographic variables. The upper age limit for which primary ASO is indicated in TGA/IVS is not yet defined.

Modified ultrafiltration improves left ventricular systolic function in infants after cardiopulmonary bypass

OBJECTIVE

Our objective was to test the hypothesis that use of modified ultrafiltration after cardiopulmonary bypass improves intrinsic left ventricular systolic function in children.

METHODS

Twenty-one infants undergoing cardiopulmonary bypass were instrumented with ultrasonic dimension transducers, to measure the anteroposterior minor axis diameter, and a left ventricular micromanometer. Patients were randomized to modified ultrafiltration (n = 11, age 226 +/- 355 days, weight 6.7 +/- 3.1 kg) or control (n = 10, age 300 +/- 240 days, weight 7.0 +/- 2.5 kg) (all differences p > 0.05 between groups). Left ventricular systolic function was assessed by means of the slope of the preload-recruitable stroke work index. Myocardial cross-sectional area was measured by echocardiography. Data were acquired immediately after separation from bypass, at steady state, and during transient vena caval occlusion. Data acquisition was repeated after 13 +/- 5 minutes of modified ultrafiltration or after 12 +/- 5 minutes without modified ultrafiltration in the control group. Inotropic drug support was the same at both study points.

RESULTS

In the modified ultrafiltration group, the filtrate volume was 363 +/- 262 ml. The hematocrit value increased from 26.0% +/- 2.7% to 36.7% +/- 9.5% (p = 0.018), myocardial cross-sectional area decreased from 3.72 +/- 0.35 cm2 to 3.63 +/- 0.36 cm2 (p = 0.04), end-diastolic length increased from 25.6 +/- 9.0 mm to 28.8 +/- 9.9 mm (p = 0.01), and end-diastolic pressure fell from 5.6 +/- 0.8 mm Hg to 4.2 +/- 0.8 mm Hg (p = 0.005), suggesting an improved diastolic compliance. In the control group, the hematocrit value, myocardial cross-sectional area, end-diastolic length, and pressure did not change (all p > 0.05). Mean ejection pressure increased in the ultrafiltration group (p = 0.001) but did not change in the control group (p = 0.22). The slope of the preload-recruitable stroke work index increased after ultrafiltration from 52.3 +/- 52.0 to 74.2 +/- 66.0 (10[3] erg/cm3) (p = 0.02) but did not change in the control group (p = 0.07). One patient from each group died in the postoperative period. Patients in the ultrafiltration group received less inotropic drug support in the first 24 hours after the operation (156.62 +/- 92.31 microg/kg in 24 hours) than patients in the control group (865.33 +/- 1772.26 microg/kg in 24 hours, p = 0.03).

CONCLUSIONS

Use of modified ultrafiltration after cardiopulmonary bypass improves intrinsic left ventricular systolic function, improves diastolic compliance, increases blood pressure, and decreases inotropic drug use in the early postoperative period.

Measurement of cerebral blood flow during cardiopulmonary bypass with near-infrared spectroscopy

OBJECTIVE

A novel noninvasive method for repeatedly measuring cerebral blood flow during cardiopulmonary bypass by near-infrared spectroscopy is described. The reproducibility of the method is investigated and a comparison is made with an established technique.

METHODS AND RESULTS

The method is derived from the Fick principle and uses indocyanine green dye, injected into the bypass circuit, as an intravascular tracer. Cerebral blood flow was measured in nine children undergoing cardiopulmonary bypass on a total of 49 occasions. Results from this study suggest that an integrating period of 4 seconds provided a consistent measurement of global cerebral blood flow. The values obtained ranged from 3.2 to 32.4 (median 15.9) ml.100 gm-1.min-1. In an additional 10 children in whom repeated measurements were made, the coefficient of variation was 11% +/- 7% (mean +/- standard deviation). In a further study, the method was compared with microsphere injection in five piglets undergoing cardiopulmonary bypass. The comparison within each animal with the linear least squares method gave values for R2 in the range 0.91 to 0.99. The gradients of the fits ranged from 0.5 to 1.8 (median 1.0). The mean difference between the two techniques was 5.7 ml.100 gm-1.min-1 or 7%. The coefficient of variation for the piglets was 14% +/- 9% (mean +/- standard deviation).

CONCLUSIONS

Indocyanine green and near-infrared spectroscopy allow frequent and repeated measurements of cerebral blood flow during cardiopulmonary bypass. The measurements are reproducible and accurately reflect changes in cerebral blood flow. It may be widely applicable both in research and clinical practice.

Carotid artery pseudoaneurysm as a complication of ECMO

Any pulsatile neck mass after extracorporeal membrane oxygenation (ECMO) must be viewed as a pseudoaneurysm of the carotid artery until proven otherwise. Prompt diagnosis is necessary utilizing ultrasound. Angiography may not be necessary. Carotid artery pseudoaneurysm requires urgent surgical intervention to prevent catastrophic hemorrhage. The utilization of cardiopulmonary bypass may facilitate safe repair.

The human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor exists as a preformed receptor complex that can be activated by GM-CSF, interleukin-3, or interleukin-5

The granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor is expressed on normal and malignant hematopoietic cells as well as on cells from other organs in which it transduces a variety of functions. Despite the widespread expression and pleiotropic nature of the GM-CSF receptor, little is known about its assembly and activation mechanism. Using a combination of biochemical and functional approaches, we have found that the human GM-CSF receptor exists as an inducible complex, analogous to the interleukin-3 (IL-3) receptor, and also as a preformed complex, unlike the IL-3 receptor or indeed other members of the cytokine receptor superfamily. We found that monoclonal antibodies to the GM-CSF receptor alpha chain (GMR alpha) and to the common beta chain of the GM-CSF, IL-3, and IL-5 receptors (beta(c)) immunoprecipitated both GMR alpha and beta(c) from the surface of primary myeloid cells, myeloid cell lines, and transfected cells in the absence of GM-CSF. Further association of the two chains could be induced by the addition of GM-CSF. The preformed complex required only the extracellular regions of GMR alpha and beta(c), as shown by the ability of soluble beta(c) to associate with membrane-anchored GMR alpha or soluble GMR alpha. Kinetic experiments on eosinophils and monocytes with radiolabeled GM-CSF, IL-3, and IL-5 showed association characteristics unique to GM-CSF. Significantly, receptor phosphorylation experiments showed that not only GM-CSF but also IL-3 and IL-5 stimulated the phosphorylation of GMR alpha-associated beta(c). These results indicate a pattern of assembly of the heterodimeric GM-CSF receptor that is unique among receptors of the cytokine receptor superfamily. These results also suggest that the preformed GM-CSF receptor complex mediates the instantaneous binding of GM-CSF and is a target of phosphorylation by IL-3 and IL-5, raising the possibility that some of the biologic activities of IL-3 and IL-5 are mediated through the GM-CSF receptor complex.

The relation between pump flow rate and pulsatility on cerebral hemodynamics during pediatric cardiopulmonary bypass

OBJECTIVES

Neurologic impairment, at least partly ischemic in origin, has been reported in up to 25% of infants undergoing cardiopulmonary bypass, with or without circulatory arrest. Controversy continues about the effect of pump flow, pulsatile or nonpulsatile, on the brain and in particular on cerebral blood flow. This study examines the relationship between pump flow rate and cerebral hemodynamics during pulsatile and nonpulsatile cardiopulmonary bypass.

METHOD

Near-infrared spectroscopy was used to determine cerebral blood flow and cerebral blood volume (measured as concentration change) in a randomized crossover study. Pulsatile and nonpulsatile flow were used for six 5-minute intervals at each of three different pump flow rates (0.6, 1.2, and 2.4 L x m2 x min(-1)) in 40 patients, median age 2 months (range 2 weeks to 20 years 5 months). The relations between pulsatile flow, pump flow rate, cerebral blood flow, hemoglobin concentration change (cerebral blood volume), mean arterial pressure, arterial carbon dioxide tension, and hematocrit value were prospectively examined by means of multivariate analysis.

RESULTS

Cerebral blood flow decreased 36% per L x m(-2) x min(-1) decrease in pump flow rate and was associated with changes in mean arterial pressure but did not differ according to pulsatility. Change in hemoglobin concentration was unrelated to changes in pulsatility of pump flow.

CONCLUSION

Cerebral blood flow is related to pump flow rate. Pulsatile flow delivered with a Stöckert pump does not increase cerebral blood flow or alter hemoglobin concentration during cardiopulmonary bypass in children.

Anaemia of chronic disease in rheumatoid arthritis: in vivo effects of tumour necrosis factor alpha blockade

Anaemia of chronic disease (ACD) is a common feature of active rheumatoid arthritis (RA). Inflammatory cytokines, particularly tumour necrosis factor alpha (TNF-alpha), interleukin-1 (IL-1) and interleukin-6 (IL-6), are thought to contribute to the pathogenesis of ACD, possibly by inhibiting erythropoietin (EPO) production. In this study, we examined the in vivo effects of TNF-alpha blockade with a chimeric monoclonal antibody, cA2, on erythropoiesis in RA patients with ACD. Administration of cA2 led to a dose-dependent increase in haemoglobin levels compared to placebo and these changes were accompanied by a reduction in both EPO and IL-6 levels. The data support the notion that TNF-alpha is important in the causation of ACD, but suggest a mechanism independent of EPO suppression. Instead, TNF-alpha may act directly on bone marrow red cell precursors.

Atrioventricular septal defect and tetralogy of Fallot: a 15-year experience

AIM

Atrioventricular septal defect and tetralogy of Fallot is a relatively uncommon lesion in which there is a risk of right ventricular dysfunction related to inlet and outlet valve problems. For this reason, conservative management involving an initial palliative procedure is often chosen. The aim of this report is to retrospectively review our experience with this lesion.

PATIENT POPULATION

35 patients with atrioventricular septal defect and tetralogy of Fallot have been surgically managed at this institution between January 1980 and June 1995. Twenty-one (60%) of these patients underwent 28 initial palliative shunt procedures. Fourteen (40%) patients underwent primary definitive repair. The criteria for choosing one management strategy over another was based on a number of factors, including age at presentation, anatomy of the lesion, and severity of symptoms. Of the 21 patients who underwent an initial shunt procedure, 15 have undergone definitive operation. Of the 6 patients who did not undergo definitive operation, three died (two directly related to complications of the shunt procedure), two are awaiting operation, and one was lost to follow-up.

RESULTS

The primary indication for operation in all patients was cyanosis. Freedom from reoperation at 5 years after definitive operation was 65.1% for all patients; most reoperations were related to left atrioventricular valve regurgitation or residual leaks across the ventricular septal defect patch. The operative mortality at definitive operation was 10.3% (70% CL 4.5-20%) for all patients. The actuarial estimate of survival 7 years following definitive repair was 77.3% (70% CL 68.7-85.9%) for all patients. The actuarial estimate of survival at 7 years was 84.4% (70% CL 73.8-95%) in the patients undergoing primary repair and 65% (70% CL 52.4-77.6%) in patients initially palliated if the mortality of the palliative shunt procedure is included (P = 0.35).

CONCLUSION

Patients with atrioventricular septal defect and tetralogy of Fallot can be successfully managed with a variety of surgical strategies. Primary repair may be a reasonable option in carefully selected patients, as this eliminates the morbidity and mortality of an initial shunt procedure and the subsequent interval between initial palliation and definitive repair.

Suppression of fever and the acute-phase response in a patient with juvenile chronic arthritis treated with monoclonal antibody to tumour necrosis factor-alpha (cA2)

Juvenile chronic arthritis (JCA) is the commonest chronic rheumatic disorder of childhood. Although conventional therapy of JCA continues to improve, many patients experience long-term ill health as a result of their disease or treatment. In adult rheumatoid arthritis (RA), similar concerns have led to the development of therapies designed to interfere in key disease processes. One such therapy is cA2, a chimeric neutralizing monoclonal antibody to the inflammatory cytokine, tumour necrosis factor-alpha (TNF-alpha). The administration of cA2 in adult RA has led to impressive short-term suppression of disease, with a good safety profile. Here, we report the first use of cA2 in childhood arthritis, choosing a patient with severe systemic-onset JCA, resistant to conventional therapies. The patient received two i.v. infusions of cA2, each at a dose of 10 mg/kg, separated by 1 week. The treatment was well tolerated and induced rapid control of fever, anorexia and serositis, together with downregulation of interleukin (IL)-6, soluble TNF receptors (sTNFR) and IL-1ra, and the acute-phase proteins C-reactive protein (CRP) and serum amyloid A (SAA). In contrast, we saw no significant improvement in joint pain or tenderness. Our findings suggest that TNF-alpha is a mediator of fever and other systemic aspects of disease in systemic JCA. TNF-alpha blockade as a treatment modality in JCA deserves further study.

The relation between arterial oxygen tension and cerebral blood flow during cardiopulmonary bypass

OBJECTIVES

Neurological impairment occurs in up to 25% of infants undergoing cardiopulmonary bypass with or without circulatory arrest. Potential causes include alterations in cerebral blood flow, hypoxia and embolisation. During cardiopulmonary bypass, arterial oxygen tension is maintained at levels which under normal conditions cause cerebral vasoconstriction; this is a potential mechanism for ischaemia. The aim of this study was to explore the relation between arterial oxygen tension and cerebral blood flow during cardiopulmonary bypass.

METHODS

Near infrared spectroscopy was used to explore the relation between arterial oxygen tension and cerebral blood flow in 14 patients (median age 8 months; range 1 month to 10 years 11 months). The relations between arterial oxygen tension, arterial carbon dioxide tension, temperature, haematocrit, pump flow rate, mean arterial pressure and cerebral blood flow, were examined using multivariate analysis.

RESULTS

There was no relation between cerebral blood flow and arterial oxygen tension, but a highly significant relation was observed between cerebral blood flow and pump flow rate, with cerebral blood flow decreasing 4.2-fold per L.m-2.min-1 decrease of pump flow rate.

CONCLUSION

There was no relation between arterial oxygen tension and cerebral blood flow during cardiopulmonary bypass, but low pump flow rate may lead to reduced cerebral blood flow.

Heart transplantation for Barth syndrome

Barth syndrome is an X-linked recessive disorder comprising dilated cardiomyopathy, muscular hypotonia, and cyclical neutropenia. Affected children usually die during infancy as a consequence of septicemia, cardiac failure, or both. We report a patient with Barth syndrome who underwent successful heart transplantation.

Stöckert roller pump generated pulsatile flow: cerebral metabolic changes in adult cardiopulmonary bypass

There is evidence that during cardiopulmonary bypass (CPB), pulsatile pump flow improves cerebral metabolism. This was a study to explore the effect of pulsatile versus nonpulsatile perfusion on cerebral lactate, pyruvate, glucose and beta-hydroxybutyrate using a Stöckert roller pump. We found no significant differences between the arterial-venous (A-V) differences of lactate, glucose and beta-hydroxybutyrate (p > 0.05). When the upward trend of A-V pyruvate was accounted for, there was again no difference (p = 0.2). Arterial lactate:pyruvate ratios were not significantly different between pulsatile and nonpulsatile pump flow (p > 0.05). Venous lactate:pyruvate ratios were significantly higher during pulsatile bypass, but when the downward trend was accounted for, the differences between pulsatile and nonpulsatile values were no longer significant (p = 0.4). Therefore, the metabolic changes were not significant. There was no significant difference in systemic vascular resistance (SVR) during pulsatile and nonpulsatile flow (p = 0.4). Pulsatile flow delivered by the Stöckert roller pump appears to have no metabolic or SVR advantages in adults undergoing CPB.

Outcomes after delayed sternal closure in pediatric heart operations: a 10-year experience

BACKGROUND

Open heart operations in young children may lead to myocardial swelling and increased lung water. Decreased intrathoracic space may then make sternal closure difficult. Delayed sternal closure may be beneficial in this setting. Potential risks of delayed sternal closure are sepsis and sternal instability.

METHODS

To assess these risks, we reviewed retrospectively 150 consecutive children who underwent delayed sternal closure after repair of complex congenital cardiac defects.

RESULTS

Diagnoses included transposition of the great arteries (66), total anomalous pulmonary venous drainage (11), and complete atrioventricular septal defects (10). Age at operation was 229 +/- 51 days (mean +/- standard error of mean). Sixteen patients required extracorporeal membrane oxygenation. Survival was 88% (133 patients). The sternum was left open for 3.86 +/- 0.29 days. Fifteen patients had minor wound infections requiring antibiotics. No patient required reexploration for mediastinitis and no patient had an unstable sternum.

CONCLUSIONS

Delayed sternal closure with sternal stenting and silicone membrane skin closure is a safe procedure in infants and children with compromised cardiac output after repair of congenital cardiac defects.

Prospective, randomized, double-blind study of high-dose aprotinin in pediatric cardiac operations

BACKGROUND

Perioperative aprotinin decreases postoperative blood loss in adults undergoing cardiac operations, but its role is less clear in children. Therefore, a trial of aprotinin in pediatric cardiac operations was conducted to study the efficacy of its use in children.

METHODS

Forty-two patients were randomly assigned to receive either high-dose aprotinin or placebo. Aprotinin efficacy was assessed using time from protamine administration to skin closure, postoperative blood loss and hemoglobin loss, and postoperative transfusion requirements. Measures of fibrinolysis (fibrin degradation product titers) and platelet preservation (beta-thromboglobulin levels) were also assessed.

RESULTS

There were no statistically significant differences between groups in any of the blood loss or transfusion parameters. Fibrin degradation product levels, measured 4 hours postoperatively, had increased significantly for control patients, but remained unchanged for the aprotinin group (p < 0.02). beta-Thromboglobulin levels increased more rapidly during cardiopulmonary bypass in the control group (p = 0.03).

CONCLUSIONS

Aprotinin appears to provide no clinical benefit in routine pediatric cardiac operations. A reduction in fibrinolysis, with perhaps an early preservation of platelet structure, is seen in the aprotinin group.

Cardiopulmonary bypass tubes and prime solutions stimulate neutrophil adhesion molecules

OBJECTIVE

To evaluate effects of the material of the cardiopulmonary bypass (CPB) tubes (polyvinyl chloride, PVC) and prime solutions on expression of neutrophil adhesion molecule CD11b and L-selectin.

METHODS

We carried out a series of experiments using donor blood from 30 healthy adult human volunteers. In all experiments, neutrophil cell surface expressions of CD11b and L-selectin were assayed immediately and serially up to 2 hours, using immune-fluorescence techniques and flow cytometry. Study 1: Effects of PVC were compared with glass and polystyrene (n = 5). Study 2: Blood was mixed with Plasma-lyte (Pl) (prime solution), Hartman solutions, albumin or not altered (control), n = 5. Study 3: The effects of changing pH of the Pl (control, neutralised and acidic solution, n = 5) were examined. Study 4: Haemodilution (undiluted, 1:1, 1:2, and 1:3, vol/vol, prime to blood, n = 5) was carried out using Pl and the subsequent changes in expressions of the adhesion molecules were analysed. Study 5: The combined effect of PVC and Pl was assessed (n = 5). Study 6: We evaluated the effect of increasing plasma water by adding sterile water to whole blood and compared it with control (n = 5).

RESULTS

Study 1: PVC, similar to glass, caused more up-regulation of CD11b and down-regulation of L-selectin than polystyrene (238 and 162% vs. 68 increase of CD11b, P < 0.001; 89 and 95% vs. 16% decrease of L-selectin, P < 0.001). Study 2: Pl and Hartman solutions caused more up-regulation of CD11b and down-regulation of L-selectin compared to albumin and control (166 and 188% vs. 26 and 44% increase of CD11b, P < 0.01; 19 and 26% vs. 10 and 6% decrease of L-selectin, P < 0.01, respectively). Study 3: Haemodilution had no effect on these molecules. Study 4: The mean of the difference between the acidic and neutral solution was 208% increase of CD11b and 30% decrease of L-selectin, P < 0.05. Study 5: The combined effect of mixing blood with Pl and exposure to PVC caused marked up-regulation of CD11b (336% increase, P < 0.01) and down-regulation of L-selectin (78% decrease, P < 0.05). Study 6: Water for injection caused marked up-regulation of CD1 1b and down-regulation of L-selectin.

CONCLUSIONS

Mixing blood with acidic prime solution and/or exposing it to PVC tubes causes up-regulation of neutrophil adhesion molecule CD11b and down-regulation of L-selectin. Neutralisation of the prime solution reduces the extent of neutrophil activation, whereas haemodilution has no effect. Increasing plasma water is stimulating to the neutrophil. Modulation of prime solutions and the material of CPB tubes may reduce neutrophil activation which may reduce patient morbidity.

Heart-lung transplantation for patients under 10 with cystic fibrosis

The outcome of patients with cystic fibrosis aged under 10 years referred for heart-lung transplantation assessment (n = 58) was determined and compared with older children (n = 109). Similar proportions were placed on to the active waiting list (64% v 71%) and received transplants (35% v 31%). Three year post-transplantation survival figures were also similar (41% v 46%), as were the figures for overall survival for those placed on to the active list (27% v 29%). Paediatricians should not be deterred from referring younger patients for transplantation.

Mixed total pulmonary venous drainage: still a surgical challenge

OBJECTIVE

The aim of this report is to review the surgical experience of a single institution with a relatively large series of patients with mixed total pulmonary venous drainage.

PATIENT POPULATION

Between January 1, 1971, and December 31, 1994, 232 patients with total pulmonary venous drainage underwent surgical correction. Twenty of these patients (8.6%) had mixed type total pulmonary venous drainage. Ages at operation ranged from 1 day to 46 months, with a median of 2.3 months.

RESULTS

Both cardiac catheterization and echocardiography were performed before operation in 12 patients. Four patients underwent only cardiac catheterization, and another four patients underwent only echocardiography. The sensitivity and specificity for catheterization were 94% and 99%, respectively; they were 31% and 100%, respectively, for echocardiography. Severe pulmonary venous obstruction was present in three patients, all of whom underwent emergency operation. Three patients (15%), all of whom had preoperative pulmonary venous obstruction, died after operation. There were two late deaths, one of pulmonary vein stenosis and the other of probable pulmonary hypertension. The actuarial survival at 10 years was 73% for all patients; patients who survived the initial operation had a 10-year survival of 87%.

CONCLUSION

The diagnosis of mixed total pulmonary venous drainage can be difficult to establish by echocardiography or at the time of operation. For patients in stable condition, cardiac catheterization may be considered if fewer than three pulmonary veins are identified by echocardiography. Pulmonary venous obstruction is relatively infrequent in this group of patients but when present impacts patient survival significantly. The long-term results with this lesion are excellent.