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M Burch

Publications and source records attributed to M Burch.

At least 37 records · Page 2Linked to original sources
PubMed1995

Ventricular expression and circulating levels of insulin-like growth factor I in heart transplant recipients.

1. Insulin-like growth factor I is a major mediator of growth-promoting activities. We studied the ventricular insulin-like growth factor I gene expression at mRNA and peptide levels in 24 heart transplant recipients (14 children and 10 adults), using 'slot blot' hybridization with insulin-like growth factor I cDNA probe and a specific radioimmunoassay. 2. Ventricular insulin-like growth factor I mRNA was detected in all the cardiac transplant children but was below the limit of detection in the cardiac transplant adults. Ventricular insulin-like growth factor I levels were significantly higher in the transplant children [174 +/- 15 (SEM; range 39-950) pg/mg soluble protein] than in transplant adults [39 +/- 2 (range 14-85) pg/mg soluble protein, P < 0.01, n = 14]. Circulating levels of insulin-like growth factor I in the cardiac transplant children [164 +/- 10 (range 105-192) ng/ml] and adults [176 +/- 15 (range 126-244) ng/ml] were within normal ranges for children and adults. 3. These results suggest that the human heart is a site for insulin-like growth factor I production and provide support for an autocrine role for insulin-like growth factor I in the ventricle, despite cardiac denervation.

Adolescent↗
PubMed1994

Dilated cardiomyopathy in children: determinants of outcome.

OBJECTIVE: To determine the outcome of dilated cardiomyopathy presenting in childhood and the features that might be useful for prognostic stratification. SETTING: Supraregional paediatric cardiology unit. DESIGN: Retrospective analysis. BACKGROUND: The natural history of dilated cardiomyopathy in children is not well characterised. Previous studies have shown a variable relation between age at presentation and outcome, and sudden death has been infrequent. METHODS: Retrospective study of 63 consecutive patients with idiopathic dilated cardiomyopathy presenting between 1979 and 1992. Survival curves were constructed by the Kaplan-Meier method. RESULTS: Age at diagnosis ranged from 1 day to 15 years (median 12 months) and follow up ranged from 1 day to 13 years (median 19 months). Actuarial survival from presentation was 79% at one year (95% confidence interval (95% CI) 66%-88%) and 61% (44%-74%) at five years. Univariate analysis showed that mural thrombus, left ventricular end diastolic pressure > 20 mm Hg, and age at presentation > 2 years were predictors of adverse outcome, but on multivariate analysis only age at presentation was significant. Left ventricular echocardiographic indices either did not improve or deteriorated in 36 children (17 of whom died, four suddenly, and three were transplanted), partially improved in 16 (three of whom died, all suddenly), and returned to normal in 11 (all of whom have survived). CONCLUSIONS: Older age at presentation and lack of improvement in systolic function are associated with an adverse outcome, and early transplantation should be considered in these patients. There is a persistent risk of late sudden death in those children in whom echocardiographic dimensions remain abnormal.

Adolescent↗
PubMed1994

Role of endothelium in the maintenance of low pulmonary vascular tone in normal children.

BACKGROUND: Resting vascular tone is low in the normal pulmonary circulation, and experimental studies have suggested that this may be due to the continuous release of endothelium-derived nitric oxide (NO), a locally acting vasodilator. We have investigated whether NO contributes to the normal control of pulmonary vascular tone and resistance in children. METHODS AND RESULTS: We studied the hemodynamic effects of NG-monomethyl-L-arginine (L-NMMA), a specific inhibitor of NO synthesis, on the pulmonary circulation of six children 2 to 17 years old (mean, 9 years) with congenital heart disease but normal pulmonary blood flow, pressure, and resistance (all had isolated left heart obstructive lesions). The diameter of a segmental pulmonary artery and pulmonary blood flow velocity were measured by quantitative angiography and intra-arterial Doppler catheters. There was a consistent, dose-dependent fall in pulmonary blood flow velocity in response to three increasing doses of L-NMMA (compared with baseline, flow velocity fell to 75 +/- 7%, 62 +/- 8%, and 40 +/- 10%, P < .01). Flow velocity returned to control values with subsequent infusion of L-arginine, the substrate for NO. Thereafter, acetylcholine, an endothelium-dependent dilator, produced an increase in flow velocity (56 +/- 10% greater than baseline, P < .01). Arterial diameter was unchanged during L-NMMA and L-arginine infusions, indicating that the major effect of each agent is to alter vascular tone distal to the segmental pulmonary arteries. CONCLUSIONS: The dilator action of endothelium-derived NO contributes to the maintenance of low resting pulmonary tone in normal children. Impairment of NO production may contribute to the elevated pulmonary vascular resistance that complicates some cases of congenital heart disease.

Arginine↗
PubMed1993

Genetic counselling in Noonan syndrome.

A clinical and echocardiographic study is presented of 117 families with Noonan syndrome. The 117 families contained 144 individuals with typical Noonan syndrome. The age range of these individuals was from one week to 45 years (mean 12.0 years). One parent was definitely affected with Noonan syndrome in only 14% of the 117 families (mother 11%, father 3%). In a further 31% of families, one parent had possible signs of Noonan syndrome, based on facial appearance only. Within the apparently sporadic group of probands there was no evidence of increased parental age. Echocardiography demonstrated no cases of subclinical cardiac disease in all first degree relatives examined, and clinical examination alone missed no case of cardiac disease. Segregation analysis of affected pedigrees confirmed autosomal dominant inheritance. If both parents had only possible or no signs of Noonan syndrome, subsequent to the birth of the first child with Noonan syndrome in a family, an empiric recurrence risk of 5% was obtained.

Adult↗
PubMed1993

Brain natriuretic peptide and fluid volume homeostasis--studies during cardiopulmonary bypass surgery.

Brain natriuretic peptide (BNP) is a recently identified cardiac ventricular hormone with diuretic, natriuretic and vasorelaxant properties. The aim of our study was to examine whether serial changes in endogenous levels of BNP were associated with fluid volume homeostasis following cardiopulmonary bypass. We studied nine patients undergoing elective cardiac surgery for the repair of cardiac abnormalities requiring cardiopulmonary bypass. Urinary levels of cyclic guanosine monophosphate (cGMP), sodium, urine output, fluid balance, and plasma levels of BNP, aldosterone, plasma renin activity (PRA) and central venous pressure (CVP) were measured before, during and after cardiopulmonary bypass. Basal pre-operative plasma BNP levels were highly elevated in all nine patients with cardiac abnormalities. During bypass, pre-operative levels of BNP, urinary cGMP and plasma aldosterone decreased significantly (p < 0.05), whereas pre-operative levels of urinary sodium and PRA were slightly reduced. During recovery following bypass levels of urinary cGMP, sodium, PRA and aldosterone returned to basal pre-operative values, whereas post-operative levels of plasma BNP were found to be three-fold below basal pre-operative levels. CVP (4.3 +/- 0.2 mmHg) during the onset of bypass increased significantly (p < 0.05) at the end of bypass (9 +/- 0.3 mmHg) followed by a modest increase post-operatively (10 +/- 0.4 mmHg). After operation only BNP had a significant correlation with urine output (r = -0.82, p < 0.02) and net fluid balance (r = -0.84, p < 0.01), whereas urinary cGMP, PRA and aldosterone all exhibited a non-significant correlation with urine output.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1993

Cardiologic abnormalities in Noonan syndrome: phenotypic diagnosis and echocardiographic assessment of 118 patients.

OBJECTIVES: The purpose of this study was to determine the incidence of cardiologic abnormalities in Noonan syndrome. BACKGROUND: The incidence of cardiac abnormalities in Noonan syndrome remains unknown, largely because of such difficulties as assembling a substantial cohort, ensuring a correct phenotypic diagnosis and providing accurate definitions of the most frequent abnormalities--pulmonary stenosis and left ventricular hypertrophy. METHODS: A cohort of 145 patients was assembled, and before cardiologic assessment two independent geneticists scrutinized the phenotype. The diagnosis was confirmed in 118 patients, and they were studied by two-dimensional and Doppler echocardiography. RESULTS: A dysplastic pulmonary valve was present in eight patients (7%) and was associated with significant stenosis in six (75%) of the eight. Significant stenosis was present in 22 (20%) of 110 patients without dysplasia. Left ventricular hypertrophy was present in 29 patients (25%) without significant pulmonary stenosis. Localized anterior septal hypertrophy was the most common pattern in 12 (41%) of 29 patients. Diffuse hypertrophy involving the entire septum and the free wall was present in nine patients (31%) and was severe (> 1.7 cm) in five. Other abnormalities included secundum atrial septal defects (10%). CONCLUSIONS: The high incidence of cardiac abnormalities suggests that echocardiographic and Doppler evaluation of patients with the Noonan phenotype is important because it will aid in genetic counseling and in the assessment of the natural history of--and, ultimately, identification of the gene(s) responsible for--Noonan syndrome.

Adolescent↗
PubMed1993

Five-year follow-up after balloon pulmonary valvuloplasty.

OBJECTIVES: The aim of this study was to assess results 5 years after balloon pulmonary valvuloplasty. BACKGROUND: Since the technique of balloon pulmonary valvuloplasty was first reported in 1982, it has become the treatment of choice for pulmonary valve stenosis. In contrast to surgical valvotomy, the long-term outcome after balloon pulmonary valvuloplasty is unknown. METHODS: We reviewed the findings in 34 patients 5.2 +/- 0.8 (mean +/- SD) years after balloon pulmonary valvuloplasty: 27 with isolated pulmonary stenosis, 5 with Noonan syndrome and 2 with previous surgical valvotomy. In eight patients (three with Noonan syndrome), a second balloon valvuloplasty was the index procedure for analysis. RESULTS: The transpulmonary gradient (mm Hg) was 74 +/- 34 before balloon pulmonary valvuloplasty, 36 +/- 26 immediately after, 22 +/- 9 at cardiac catheterization in 29 patients 6 +/- 0.6 months later and 19 +/- 10 by Doppler study at 5 years. At 5 years 26 patients (group A) had a residual gradient of < or = 20 mm Hg; the remaining 8 (group B) had a gradient of > 20 mm Hg. Four group B patients had Noonan syndrome (p = 0.01). Balloon/pulmonary valve diameter ratio was larger for group A patients than for group B patients with isolated pulmonary stenosis (1.20 +/- 0.10 vs. 1.00 +/- 0.07, p = 0.005); larger balloons were used in group B patients with Noonan syndrome (1.30 +/- 0.10). Group A patients were more likely than group B patients to have significant pulmonary incompetence (6 of 24 vs. 0 of 8) and had a greater right ventricle/left ventricle long-axis diastolic dimension ratio (0.47 +/- 0.10 vs. 0.35 +/- 0.04, p = 0.05). In the subgroup of five patients with Noonan syndrome and two with prior surgical valvotomy, the transpulmonary gradient was reduced from 74 +/- 24 mm Hg before balloon valvuloplasty to 23 +/- 12 mm Hg at 5 years. In addition, two patients with isolated pulmonary valve stenosis had pulmonary valve dysplasia by angiographic criteria: transpulmonary gradients of 85 and 56 mm Hg were reduced to 20 and 11 mm Hg, respectively, at 5 years. CONCLUSIONS: Relief of obstruction persists at 5 years especially if oversized balloons are used. Acceptable results can be obtained in patients with a dysplastic valve. More complete relief of right ventricular outflow gradient is associated with increased right ventricular dimension, probably because more pulmonary incompetence is induced. This is well tolerated at 5 years but may be important in the longer term.

Blood Pressure↗
PubMed1993

Ventricular expression of brain natriuretic peptide gene following orthotopic cardiac transplantation in children--a three year follow up.

OBJECTIVE: The aim was to examine ventricular brain natriuretic peptide (B-type natriuretic peptide, BNP) gene expression and to determine its relationship with ventricular BNP and circulating BNP levels in paediatric cardiac transplant recipients, over a three year period after transplantation. METHODS: Total RNA extracted from endomyocardial right ventricular biopsy tissues (n = 26) of 13 cardiac transplant recipients (age range 5-17 years) and 10 normal hearts obtained at necropsy (age range 19-76 years) as controls was analysed by northern and slot blot hybridisations. Specific radioimmunoassay techniques were used to determine levels of BNP and atrial natriuretic peptide (A-type natriuretic peptide, ANP) in plasma (n = 26) and ventricular biopsy (n = 26) samples. RESULTS: Ventricular BNP messenger ribonucleic acid (mRNA) levels from slot blot hybridisations in the transplanted heart [122(3) arbitrary units, range 97-143] were significantly higher (p < 0.01) than in the normal heart [63(5) arbitrary units, range 37-98]. Northern blot hybridisations confirmed this result and gave a major BNP mRNA transcript of approximately 900 nucleotides. There was no significant relationship between ventricular BNP mRNA levels and ventricular BNP (r = 0.15, p = 0.5, n = 26) or plasma BNP levels (r = 0.16, p = 0.4, n = 26). There was also no significant relationship between ventricular BNP mRNA levels and any of the haemodynamic variables, or immunosuppressive drugs. A ventricular ANP RNA transcript of approximately 900 nucleotides was detected in the transplanted heart but was below the limit of detection in the normal heart. For the long term study, increased levels of BNP and ANP in both plasma and ventricular samples were observed in the first year after transplantation, with a significant reduction (p < 0.01) in levels three years later. CONCLUSIONS: Ventricular BNP gene expression is increased at the mRNA level after heart transplantation in children. Expression of both ventricular BNP mRNA and ANP mRNA in the transplanted heart may be an important response in the modulation of cardiac function after transplantation.

Adolescent↗
PubMed1993

Cardiac transplantation affects ventricular expression of brain natriuretic peptide.

OBJECTIVE: The aim was to examine the ventricular expression of brain natriuretic peptide (BNP) in the transplanted human heart. METHODS: Serial right ventricular biopsies (n = 68) and plasma samples (n = 68) were obtained for measurement of BNP and atrial natriuretic peptide (ANP) from 14 orthotopic cardiac transplant recipients from 1-74 weeks after transplantation. Right ventricular specimens (n = 10) were also obtained from normal hearts during necropsy as controls. RESULTS: Mean ventricular BNP in cardiac transplant recipients was higher (p < 0.05) than in normal hearts, at 13531(SEM 2244) pg.mg-1 soluble protein (range 3232-109448) v 56(11) pg.mg-1 (range 16-91). Ventricular BNP and ANP values were correlated (r = 0.57, p < 0.05). Plasma BNP concentrations were higher (p < 0.05) than plasma ANP concentrations, at 202(16) pg.ml-1 (range 84-655) v 100(12) pg.ml-1 (range 8-484), and were raised (p < 0.05) in comparison with normal plasma BNP concentrations of 20(1.8) pg.ml-1 (range 10-23). Mean ventricular BNP was correlated with time after transplant (r = 0.72, p < 0.05, n = 68) and with mean plasma BNP (r = 0.80, p < 0.05, n = 14). There was no significant relationship between BNP levels and intracardiac or systemic blood pressure, or prednisolone dose (0.1-0.3 mg.kg-1.d-1). The increase in ventricular BNP with time after transplant was not explained by cardiac rejection assessed from histology, and plasma BNP was not significantly increased during rejection episodes. CONCLUSIONS: High levels of BNP are synthesised and secreted by the transplanted human ventricle, and the transplanted ventricle may be an important source of circulating BNP. The significant positive association between ventricular BNP and time after transplant suggests a possible self compensatory mechanism or functional adaptation of the transplanted heart which may be beneficial to ventricular function.

Adolescent↗
PubMed1993

Studies of cardiopulmonary bypass in children: implications for the regulation of brain natriuretic peptide.

OBJECTIVE: The aim was to examine the influence of cardiopulmonary bypass on brain natriuretic peptide (BNP) and on hormones of importance in the control of sodium and water balance and blood volume. METHODS: Nine patients (mean age 4 years, range 2-9) undergoing cardiac surgery were studied. Blood samples were taken before, during, and up to 24 h after bypass. Plasma levels of BNP, atrial natriuretic peptide (ANP), arginine vasopressin (AVP), plasma renin activity, aldosterone, and catecholamines were measured. RESULTS: Preoperative concentrations of plasma BNP [573(SEM 68) pg.ml-1] and ANP [332(74) pg.ml-1] were greatly increased (p < 0.05) before bypass in all patients when compared to normal levels in children [BNP = 31(4) pg.ml-1; ANP = 27(3) pg.ml-1, n = 28]. With general anaesthetic and sternotomy, there were large reductions (p < 0.05) in both plasma BNP [180(62) pg.ml-1] and plasma ANP [163(59) pg.ml-1]. During bypass, there were no further significant decreases in plasma ANP or BNP concentrations compared with preoperative levels. Postoperatively, plasma BNP gradually increased for 12 h, to 170(28) pg.ml-1, whereas plasma ANP showed a further small decrease, to 107(20) pg.ml-1. However, postoperative plasma levels of both ANP and BNP remained well below preoperative values (p < 0.01). Plasma AVP increased rapidly within 15 min of the onset of bypass, reaching a peak value of 153(5) pg.ml-1 after 45 min. Off bypass, plasma AVP decreased slowly and was still almost 10-fold above preoperative levels 12 h after end of bypass [137(11) pg.ml-1]. Mean central venous pressure decreased during the onset of bypass, from 4.3(1.9) to 0.4(1.1) mm Hg (p < 0.05), and increased again at the end of bypass, to 9.0(3.3) mm Hg (p < 0.05); there was little further change during the postoperative period. CONCLUSIONS: The major source of plasma BNP in patients with congenital heart disease is the cardiac ventricle. The lower plasma ANP and BNP levels and the narrow band of change in central venous pressure following surgical repair of cardiac abnormalities may be a response to improved cardiac function.

Aldosterone↗
PubMed1993

Ventricular expression of atrial natriuretic peptide after orthotopic cardiac transplantation.

In order to determine if atrial natriuretic peptide is produced by the human ventricle after transplantation, specimens were obtained from 54 separate right ventricular endomyocardial biopsies from 14 transplant recipients (age range 10-19 years) and were analyzed with simultaneous plasma samples. Radioimmunoassay techniques were used to determine plasma and tissue levels of atrial natriuretic peptide in each biopsy specimen, and blot hybridizations with the atrial natriuretic peptide c deoxyribonucleic acid probe were performed once for each patient. Mean plasma levels of atrial natriuretic peptide were obtained from the right ventricle (106 +/- 12 pg/ml); there was a positive correlation with end diastolic pressure (r = 0.7, P < 0.0001). Plasma levels, however, were not significantly increased during rejection episodes. Atrial natriuretic peptide was detectable in all ventricular biopsy specimens--mean 989 +/- 164 pg/mg soluble protein. Mean tissue level during rejection episodes was 1163 +/- 17 and following treatment of rejection was 411 +/- 147--however, this difference was not significant (P = 0.55). In 6 patients biopsied within 1 month of transplantation initial myocardial levels were significantly higher than those obtained at the following biopsy (P < 0.05). Despite these initially high tissue levels no correlation was found with time posttransplantation. Ventricular tissue levels positively correlated with systolic ventricular pressure, r = 0.3, P < 0.05, but there was no significant correlation with other hemodynamic parameters. The normalized atrial natriuretic peptide messenger ribonucleic acid signal from the slot blot hybridization was 59 +/- 6 mm (peak height of signal intensity) range 20-110 mm. The expression of atrial natriuretic peptide gene was also confirmed by Northern blot analysis. The ventricular messenger ribonucleic acid signal contained a single hybridizing band of approximately 920 nucleotides. Thus, we have demonstrated that atrial natriuretic peptide production by the human ventricle is independent of innervation. The consistent atrial natriuretic peptide gene expression and detection by radioimmunoassay in apparently healthy ventricles was unexpected but may reflect the use of immunosuppressive drugs, or perhaps subclinical graft dysfunction.

Adolescent↗
PubMed1993

Purchasing quality: the South Lincolnshire approach.

Describes the authority's strategy, recording system, visiting programme, and guide to monitoring. Describes four developments in detail which South Lincolnshire's review of its quality monitoring approach has stimulated. The strategy identifies three levels of monitoring activity: an overview, a means of identifying when closer monitoring is indicated, and causes for concern; a selective view, a means of assessing the severity of causes for concern; and an investigative view, to examine and identify solutions to confirmed problems. Explains how the strategy identifies corporate responsibility for quality monitoring, and how this may be achieved; how the "monitoring matrix" enables a comparative overview of each provider's compliance to purchaser standards. An up-to-date record of progress on individual standards is constantly available. Quality monitoring visiting can be hit or miss. The South Lincolnshire approach attempts to minimize this through the management of the visit and the use of a pocket guide to monitoring. The guide's objective is to provide a practical guide to monitoring. An attempt has also been made to unveil some of the mystique surrounding quality.

England↗
PubMed1993

Investigation of vascular compression of the trachea: the complementary roles of barium swallow and echocardiography.

To determine the preferred investigation of congenital vascular compression of the trachea, preoperative investigation in 40 patients undergoing surgery 1981-91 was analysed. The importance of preoperative identification of detailed arterial anatomy in determining surgical technique was also assessed in 122 consecutive patients undergoing surgery 1952-91. Of the 40 patients (median age 5 months) seen 1981-91, barium swallow before referral suggested the diagnosis of vascular compression in 26 of 27 (96%). Angiography (1/3), bronchoscopy (0/6), and echocardiography (2/6) were generally unhelpful in diagnosing vascular compression before referral. Echocardiography was performed after referral in 18 consecutive patients since 1986 and the correct arterial anatomy was identified in 16 (88%); hyperinflation resulted in inadequate images in the two others. Barium swallow is the investigation of choice to screen for suspected vascular compression of the trachea; echocardiography at the referral centre can define the arterial anatomy in nearly all patients. Further investigation can be reserved for selected cases.

Aorta, Thoracic↗
PubMed1993

Severe unconjugated hyperbilirubinaemia with infradiaphragmatic total anomalous pulmonary venous connection.

An 8 day old girl with infradiaphragmatic total anomalous pulmonary venous connection presented with severe unconjugated hyperbilirubinaemia; exchange transfusion resulted in haemodynamic deterioration. Hyperbilirubinaemia is a rare complication of this condition, however exchange transfusion should be avoided. The diagnosis can be made on the neonatal unit by ultrasound demonstration of dilated hepatic portal veins.

Exchange Transfusion, Whole Blood↗
PubMed1992

A clinical study of Noonan syndrome.

Clinical details are presented on 151 individuals with Noonan syndrome (83 males and 68 females, mean age 12.6 years). Polyhydramnios complicated 33% of affected pregnancies. The commonest cardiac lesions were pulmonary stenosis (62%), and hypertrophic cardiomyopathy (20%), with a normal echocardiogram present in only 12.5% of all cases. Significant feeding difficulties during infancy were present in 76% of the group. Although the children were short (50% with a height less than 3rd centile), and underweight (43% with a weight less than 3rd centile), the mean head circumference of the group was on the 50th centile. Motor milestone delay was usual, the cohort having a mean age of sitting unsupported of 10 months and walking of 21 months. Abnormal vision (94%) and hearing (40%) were frequent findings, but 89% of the group were attending normal primary or secondary schools. Other associations included undescended testicles (77%), hepatosplenomegaly (50%), and evidence of abnormal bleeding (56%). The mean age at diagnosis of Noonan syndrome in this group was 9.0 years. Earlier diagnosis of this common condition would aid both clinical management and genetic counselling.

Adolescent↗
PubMed1992

Myocardial disarray in Noonan syndrome.

OBJECTIVE: To characterise the histopathology of the left ventricular hypertrophy commonly associated with Noonan syndrome by assessing the extent of myocyte disarray and therefore to define one aspect of the relation between this disease and idiopathic hypertrophic cardiomyopathy. DESIGN: Blinded histological analysis. SETTING: Hospital medical school. PATIENTS: Six hearts of children with the Noonan phenotype and isolated ventricular hypertrophy were compared with age and sex matched controls. METHODS: Histological analysis was performed with an image analyser under light microscopy. Representative sections from the entire left ventricular free wall were examined. Results were expressed as the percentage of fields showing disarray related to the number of fields evaluated: 100 fields were examined for each patient. RESULTS: In the patients with Noonan syndrome myocardial disarray was present in the ventricular septum in 24 (5.7)% (mean (SD)) of fields and in the free wall in 22.2 (6.8)%. In the controls disarray was present in the septum in 3.8 (2.3)% of fields and in the free wall in 2.4 (2.8)%. In both regions the extent of disarray was significantly greater in patients with Noonan syndrome (p < 0.0005; 95% confidence interval 14 to 26.3 for the septum: p < 0.005, 95% confidence interval 11.4 to 28.2 for the free wall). CONCLUSIONS: The ventricular hypertrophy associated with Noonan syndrome is histologically similar to hypertrophic cardiomyopathy but whether the two diseases are the expression of the same genetic defect remains to be determined.

Child↗
PubMed1992

Influence of cardiopulmonary bypass on water balance hormones in children.

OBJECTIVE: To determine the changes in the endocrine mechanisms of fluid balance after cardiopulmonary bypass in children. DESIGN: Prospective study; analysis of numbered plasma samples performed blind with respect to clinical data. SETTING: Regional paediatric cardiothoracic unit. PATIENTS: Nine patients, median age 4, range 2 to 9 years, five males. Patients under the age of 1 year were excluded because of the frequent blood sampling involved. MAIN OUTCOME MEASURES: Plasma concentrations of atrial natriuretic peptide (ANP), arginine vasopressin, plasma renin activity, aldosterone, noradrenaline and adrenaline, and urinary concentrations of cyclic guanosine monophosphate (cGMP) as measured by radioimmunoassay. RESULTS: After 30 minutes of cardiopulmonary bypass plasma atrial natriuretic peptide (ANP) decreased from (mean (SEM)) 151 (71) pg/ml to 52 (44) pg/ml (NS), and urinary production of its second messenger cyclic guanosine monophosphate (cGMP) decreased from 1286 (600) pmol/ml to 151 (414) pmol (p < 0.05). Other plasma concentrations of hormones studied did not change significantly although arginine vasopressin, adrenaline, and noradrenaline increased whereas aldosterone and plasma renin activity decreased. After cardiopulmonary bypass stopped there was an immediate and significant rise in plasma ANP, but within the next 24 hours plasma ANP declined significantly (p < 0.05), decreasing from 294 (49) pg/ml to 64 (29) pg/ml at 22 hours. In the postoperative period there was a significant correlation between plasma ANP and both mean fluid balance (r = 0.96, p < 0.001) and mean urine output (r = 0.97, p < 0.001). Plasma aldosterone peaked (p < 0.05) at 22 hours after operation, and argine vasopressin peaked (p < 0.05) at two hours and then declined (p < 0.05) to a trough at 24 hours. Plasma renin activity, adrenaline, noradrenaline, and urinary cGMP concentrations, and mean central venous pressure did not change significantly in the postoperative period. CONCLUSION: The changes documented show the differing pattern of release of water balance hormones invoked by cardiopulmonary bypass. The central role of ANP is shown by its strong correlation with urinary output and its similarly strong relation to fluid balance.

Aldosterone↗