Meiotic crossing-over in nondisjoined chromosomes of children with trisomy 21 and a congenital heart defect

We have used DNA polymorphisms to study meiotic crossovers of chromosome 21q in 27 nuclear families. Each family had a child with Down syndrome and a congenital heart defect. Twenty DNA polymorphisms on chromosome 21 were used to determine parental and meiotic origin of nondisjunction and to identify crossovers. Twenty-four cases were of maternal origin, and three were of paternal origin. Twenty-two unequivocal crossover events were identified. Sixteen crossovers were observed in 22 chromosome pairs nondisjoining at the second meiotic division. Fifty percent of crossover events in MI nondisjunction are detectable by molecular genetic means. Thus, the results suggest that, in this sample, each nondisjoined chromosome 21 pair has been involved in at least one crossover event.

Congenital heart disease in CHARGE association

This study reviews the spectrum of congenital heart disease and associated anomalies in 59 patients with the CHARGE association. We have analyzed our clinical experience in managing the cardiovascular anomalies and have reviewed outcome and risk factors for mortality. This study also highlights problems of cardiac management in children born with multiple system involvement. Twenty patients have died; actuarial survival was 78% at 1 year and 60% at 10 years. In only four of the nonsurvivors could their demise be ascribed to their underlying congenital heart disease. We found the outlook for survival was poor if more than one of the following three features were present; cyanotic cardiac lesions, bilateral posterior choanal atresia, or tracheoesophageal fistula. However, mortality was largely due not to the structural heart or choanal abnormalities, but instead reflected the underlying pharyngeal and laryngeal incoordination which resulted in aspiration of secretions. Furthermore, outcome is likely to be improved if collaboration between specialist surgical teams allows necessary procedures to be performed using the minimum of anesthetics. Examination of both the short- and long-term management of these children has stressed the importance of a multidisciplinary approach to their care. The pattern of cardiac defects was not random; lesions within the Fallot spectrum accounted for 33% of their congenital heart disease. Atrioventricular septal defects were also overrepresented. Not all cardiovascular defects could be explained by hypothesizing a neural crest etiology.

CHARGE and esophageal atresia

CHARGE association was diagnosed in 61 infants, 20 of whom died, mainly during the first 2 years of life. Esophageal atresia and/or tracheoesophageal fistula were present in 10 neonates. Axial skeletal anomalies occurred in 7 of the 10, but none had preaxial limb defects typical of the VATER association. All had major cardiac anomalies, predominantly tetralogy of Fallot. The majority of patients had primary repair of the esophagus. The postoperative course was stormy in all patients, with a high incidence of complications and 70% died. The recognition of features of the CHARGE association is important because it has major prognostic and therapeutic implications.

Morbid anatomy in neonates with Ebstein's anomaly of the tricuspid valve: pathophysiologic and clinical implications

The hearts of six neonates with Ebstein's anomaly of the tricuspid valve who died in the 1st month of life were compared with hearts of six age- and size-matched control neonates. All six hearts had morphologically severe disease with gross right atrial dilation and marked apical displacement of the tricuspid valve. All had a secundum atrial septal defect and four had additional cardiac lesions (pulmonary atresia in two, ventricular septal defect in two). There was significant thinning of the right ventricular free wall distal to the tricuspid valve (3 +/- 0.2 mm vs. control 4.2 +/- 0.2, p less than 0.01) and right ventricular fiber diameter was reduced (7.2 +/- 0.3 microns vs. control 11.4 +/- 0.6, p less than 0.001). The fibrous tissue content of both right and left ventricular free walls was increased (right, 29.3 +/- 2.6% vs. control 8.7 +/- 1.1, p less than 0.001; left, 23.2 +/- 1.5% vs. control 8.5 +/- 0.7%, p less than 0.001). Although the right ventricular abnormalities might be explained by hemodynamic stress in utero, abnormalities of the left ventricular free wall suggest that either genetic or nonhemodynamic environmental factors are involved in the morphogenesis of this condition. Increased right and left ventricular fibrosis may contribute to the poor early outcome in this group and may predispose to late complications, such as subnormal exercise performance, hemodynamic deterioration or late sudden death that may occur in patients with Ebstein's anomaly who survive the neonatal period.

Outcome in neonates with Ebstein's anomaly

The presentation and outcome of 50 patients with neonatal Ebstein's anomaly seen from 1961 to 1990 were reviewed. The majority (88%) presented in the 1st 3 days of life; cyanosis (80%) was the most common presenting feature. Associated defects, present in 27 infants (54%), included pulmonary stenosis in 11 and atresia in 7. Nine patients (18%) died in the neonatal period; there were 15 late deaths (due to hemodynamic deterioration in 9, sudden death in 5 and a noncardiac cause in 1) at a mean age of 4.5 years (range 4 months to 19 years). Actuarial survival at 10 years was 61%. A new echocardiographic grade (1 to 4 in order of increasing severity of the defect) was devised with use of the ratio of the area of the right atrium and atrialized right ventricle to the area of the functional right ventricle and left heart chambers. Cardiac death occurred in 0 of 4 infants with grade 1, 1 (10%) of 10 with grade 2, 4 (44%) of 9 with grade 3 and 5 (100%) of 5 with grade 4. In a multivariate analysis of clinical and investigational features at presentation, echocardiographic grade of severity was the best independent predictor of death. Neonates with Ebstein's anomaly have a high early mortality rate and those surviving the 1st month of life remain at high risk of late hemodynamic deterioration or sudden death. Echocardiographic grading of severity of the defect permits prognostic stratification.

Relapse following goniotomy for congenital glaucoma due to trabecular dysgenesis

Three hundred and thirty-five eyes of 210 patients with congenital glaucoma due to trabecular dysgenesis were treated by goniotomy as the primary procedure in infancy. In 313 eyes (93.5%) glaucoma was controlled at one year following surgery. Using Kaplan Meier actuarial survival analysis we found that eyes controlled in infancy by one or more goniotomies are at risk of relapse of glaucoma for at least 15 years although 93% of eyes are still controlled five years after the initial surgery. Patients whose symptoms of congenital glaucoma presented at birth were more likely to relapse than those whose symptoms developed in the first few months of life. Eyes requiring multiple goniotomies in infancy were more likely to relapse than those controlled by a single procedure.

Early and late arrhythmias after the Fontan operation: predisposing factors and clinical consequences

OBJECTIVE

To study the incidence, predisposing factors, and clinical significance of arrhythmias early and late after the Fontan operation for congenital heart disease.

PATIENTS AND METHODS

All 104 consecutive patients undergoing Fontan repair from 1975 to 1988 were studied retrospectively. Hospital records were reviewed for perioperative arrhythmia. Clinical information and annual electrocardiograms were available for all 78 hospital survivors during a follow up of up to 13 years (mean 3.7 years). Ambulatory electrocardiographic monitoring was performed in 67 patients (81%).

RESULTS

Eleven patients (10.6%) developed a perioperative tachycardia (eight, atrial flutter; three, His bundle tachycardia). Multivariate analysis showed that raised preoperative mean pulmonary artery pressure and low aortic saturation were significant risk factors for the development of atrial flutter (r2 = 0.32, p = 0.0001) but not for His bundle tachycardia. Despite intensive medical treatment 10 of these 11 patients died. At the last visit 72 (92%) of the 78 patients were in sinus rhythm on their standard 12 lead electrocardiogram. Junctional rhythm was present in three patients, two patients had atrial flutter, and one had a paced rhythm. Ambulatory monitoring did not show important bradycardia or ventricular arrhythmias. Actuarial survival free of supraventricular arrhythmia was 82% at eight years after operation. Multivariate analysis identified older age, increased right atrial size, and raised mean preoperative pulmonary artery pressure as risk factors for arrhythmia during intermediate follow-up (r2 = 0.46, p less than 0.001). Late tachycardias, in contrast to those occurring in the perioperative period, were not associated with an increased mortality.

CONCLUSIONS

Except for his bundle tachycardia in the perioperative period, early and late arrhythmias after a Fontan operation seem to be a consequence of adverse preoperative and postoperative haemodynamic function. The perioperative outcome is therefore poor even when the patient can be restored to sinus rhythm. Medical and surgical modifications to improve the haemodynamic disturbances associated with arrhythmias are therefore indicated.

Incidence and management of airway problems in the CHARGE Association

The airway problems associated with anaesthesia in patients with the CHARGE Association have been underreported. We undertook a retrospective review of 50 cases, of which anaesthetic records were available for 37 patients. Apart from choanal atresia and cleft lip and palate, 56% of patients has some other upper airway abnormality. There appeared to be greater difficulty in tracheal intubation with increase in age in four patients. The incidence and management of airway abnormalities are discussed.

Microdeletions within 22q11 associated with sporadic and familial DiGeorge syndrome

DiGeorge syndrome (DGS) is a developmental field defect of the third and fourth pharyngeal pouches. It is associated with deletion of 22q11 in 11% of cases. Molecular genetic analysis with probes from 22q11-pter reveals that a subset of markers is hemizygous in DGS patients with normal karyotypes. There is no apparent difference in the phenotype or the severity of the disorder between patients with the smallest detectable submicroscopic deletion and those with the largest cytogenetically visible abnormality. A microdeletion was found in a mildly affected child and in the severely affected child of a mildly affected father. Dysmorphology, especially cardiac outflow tract anomalies, resulting from 22q11 deletion may be more common than currently realized since chromosomes are unlikely to be checked if the complete spectrum of DGS is not present. Antenatal diagnosis, through detection of hemizygosity at 22q11, will be a possibility for mildly affected parents unwilling to risk the birth of a severely affected child.

Perioperative monitoring of total body water by bio-electrical impedance in children undergoing open heart surgery

Knowledge of the changes in total body water (TBW) following cardiac surgery (OHS) in children would be of value in fluid therapy and in researching the causes and management of capillary leak. We have validated a bioelectrical impedance technique (BEI) for non-invasive estimation of TBW in children after OHS. We report the use of this method in a longitudinal study. Twenty patients (mean age 4.7 years +/- 3.5 (SD), mean weight (WT) 16.2 kg +/- 1 kg) undergoing a variety of complex OHS procedures were studied from 1 day preoperatively to 4 days postoperatively. Anaesthetic and basic bypass (CPB) techniques were uniform. Six patients underwent CPB at less than 20 degrees C, 10 at 20 degrees - 25 degrees C and 4 at 26 degrees - 33 degrees C. TBW (BEI), core (ctemp) and peripheral (ptemp) temperatures and fluid balance (TFB) were recorded at frequent intervals. TBW (by BEI) rose (P less than 0.001) following CPB in all patients from 62% +/- 9% (SD) body weight preoperatively to 73% +/- 13% in the ICU (an increase of 11% +/- 5%). TBW remained significantly elevated until the 3rd postoperative day. Multivariate analysis (MVA) confirmed that TBW was significantly related to TFB, but not to ctemp or ptemp. MVA also revealed smaller patient size (height and weight), younger age and longer CPB time as incremental risk factors for the rise in TBW.

CONCLUSIONS

(1) BEI permits the non-invasive study of TBW in children after OHS, when TBW variation may be considerable. (2) The smaller the child and the longer the CPB, the greater the rise in TBW. (3) The technique should be a valuable tool in researching the major water fluxes associated with CPB in children.

Neural cell adhesion molecule (N-CAM) in fetal and mature human heart

Using Northern blot analysis and immunoblotting techniques we report for the first time, that the neural cell adhesion molecule, N-CAM, is expressed in human heart. We found several different N-CAM transcripts in human fetal (13-17 weeks gestation) and mature heart (left ventricle from a 5-year-old child). Northern blotting showed that a 5.2 kb transcript was the most abundant and progressively increased with age, both in fetal and mature heart. These transcripts may correspond with the different protein isoforms shown by immunoblotting. We also confirmed the presence of N-CAM in fetal and mature myocytes by immunohistochemical techniques, using a monoclonal antibody to human N-CAM. Results demonstrated that N-CAM is mainly confined to the myocyte cell surface.

The eye in the CHARGE association

CHARGE association includes patients with at least four features prefixed by the letters of the mnemonic: Coloboma, Heart defects, Atresia of the choanae, Retarded growth and development, Genital hypoplasia, Ear anomalies and/or hearing loss. Many also have facial palsy. We report a series identified by collaboration within one centre of all specialties concerned in the management of the CHARGE association. Ocular abnormalities were found in 44 out of 50 patients with the CHARGE association. Of these, 41 had 'typical' colobomata. The majority had retinochoroidal colobomata with optic nerve involvement, but only 13 patients had an iris defect. Two patients had atypical iris colobomata with normal fundi. Additional features were microphthalmos in 21 patients, optic nerve hypoplasia in four, nystagmus in 12, and a vertical disorder of eye movement in four of the 22 cases with facial palsy. We report an incidence of coloboma in the CHARGE association of 86% (43/50) compared with a previous cumulative reported incidence of 66% (112/170). We believe that there may have been previous underdiagnosis of colobomata in children with multiple congenital abnormalities.

Congenital heart anomalies in patients with clefts of the lip and/or palate

The nature and severity of congenital heart disease in 78 patients who presented with clefts of the lip and/or palate is reported. The prevalence of bilateral cleft lip and palate in patients with heart lesions was much higher than in cleft patients with normal hearts. Cardiac defects were predominantly conotruncal. Tetralogy of Fallot was present in 24 percent of patients; the prevalence of transposition, atrioventricular septal defect, and truncus arteriosus was also disproportionately high. Patients with conotruncal defects had a greater prevalence of either unilateral or bilateral cleft lip and palate. Most patients with congenital heart disease and clefting had additional abnormalities. Anomalies of other systems were found to be present in 87 percent of patients.

The natural and "unnatural" history of congenitally corrected transposition

The data available on 111 patients with congenitally corrected transposition and 2 adequate ventricles managed over the 20-year period to 1988 were reviewed retrospectively. The ages of survivors ranged from 1 to 58 years (median 20) and all but 10 had additional anatomic abnormalities. Tricuspid valve abnormalities were more prevalent in patients symptomatic with heart failure (26 of 43 patients) than those whose main problem was cyanosis (11 of 52 patients); all dysplastic or Ebstein valves were at least moderately incompetent. Intracardiac repair of the lesion was attempted in 51 patients with 11 early deaths; in multivariate models, the risk factors for early death or a bad early outcome or poor result 6 months later related to poor preoperative symptomatic status (especially from heart failure), impaired right ventricular function, heart block and younger age at surgery. Patients with more than mild preoperative tricuspid regurgitation whose valves were not replaced did very poorly. Thus, patients symptomatic from heart failure should probably be repaired early in the natural history of the disease, before the systemic right ventricles dilate. By contrast, the course of patients who were predominantly cyanosed was more stable in early childhood and their surgical outcome was less compromised by poor preoperative symptomatic status; their intracardiac repair can probably be delayed until symptoms become unacceptable.

Exercise responses in patients with congenital heart disease after Fontan repair: patterns and determinants of performance

After a Fontan repair for congenital heart disease, 42 patients underwent graded supine bicycle exercise tests at levels relevant to normal daily activities. Results were compared with those of 28 age-matched normal control subjects. At rest, the cardiac index, stroke index and systolic blood pressure were comparable in both groups, but increases with exercise were smaller in the patients with a Fontan circulation. The heart rate at rest was higher in the Fontan group, but this difference disappeared as soon as exercise started. To determine whether there are limitations intrinsic to the Fontan circulation at these levels of exercise, the 10 best performers were compared with 10 age-matched control subjects; no differences were found in cardiac index, stroke index, heart rate or blood pressure at any exercise level. Analysis of the determinants of cardiac output showed that at the other end of the spectrum poor performance after a Fontan operation did not result from inadequate levels of heart rate, but from an inability to increase or maintain stroke volume. Multivariate analysis demonstrated that impairment of ventricular contractility, only when severe, predicted limited performance. There was no evidence of increased afterload, particularly in the poor performers. Therefore, ventricular filling, which is determined primarily by the pulmonary vascular bed, appears to be a major determinant of functional result after a Fontan repair.

Endothelin-1 mRNA is widely expressed in porcine and human tissues

Endothelin-1 (ET-1) is a potent vasoconstrictor peptide isolated from porcine endothelial cells. We have previously demonstrated widespread binding sites for ET-1 in blood vessels, heart, kidney, adrenal, lung, and brain in a distribution that paralleled that of endothelial cells. To determine whether these cells are capable of synthesizing ET-1 in close proximity to its binding sites, amplification of cDNA using the polymerase chain reaction and in situ hybridization were used to study the distribution of ET-1 mRNA. We have found widespread transcription of ET-1 mRNA in human and porcine tissues. The identity of the transcripts was confirmed by prediction of restriction fragment lengths or sequencing. In situ hybridization in the kidney showed that the regional expression of these transcripts is localized, probably to small blood vessels, but the failure to visualize ET-1 mRNA in the capillaries may reflect absence of expression or insufficient sensitivity of the technique. These results should permit investigation of the role of ET-1 as a local factor in vascular pathophysiology.

Normal values for noninvasive estimation of left ventricular contractile state and afterload in children

The outcome and suitability for therapeutic interventions in children with congenital heart disease depend frequently on left ventricular function. Congenital heart disease is characterized by changes in loading conditions, making it difficult to assess ventricular contractility using conventional load-dependent indexes. Two-dimensional and M-mode echocardiography and arterial blood pressure were used to study left ventricular morphometrics and contractility in 44 normal children, aged 2 to 12 years. Left ventricular end-systolic and end-diastolic length, diameter, wall thickness, volume and mass all showed linear increases with body surface area (p less than 0.001 in all). Shortening and ejection fractions, velocity of circumferential fiber shortening, morphometric ratios and endocardial meridional and circumferential stress (mean 46 and 115 g/cm2, respectively) all remained constant. A load-independent measure of the normal resting left ventricular contractile state was determined by relating the rate-corrected velocity of circumferential fiber shortening to end-systolic endocardial meridional and circumferential stress; there was an inverse linear correlation (r = -0.641 and -0.557 respectively, p less than 0.001). These data provide a quantitative basis for assessment of myocardial hypertrophy, afterload and contractile state in childhood.

Who's in CHARGE? Multidisciplinary management of patients with CHARGE association

Clinical experience of 50 patients with the CHARGE association is reviewed and problems with management of children born with multiple system involvement is highlighted. It was found that the outlook for survival was poor if more than one of the following three features was present: cyanotic cardiac lesions, bilateral posterior choanal atresia, or tracheo-oesophageal fistula. Mortality was largely due not to the structural heart defects or choanal abnormalities, but reflected underlying pharyngeal and laryngeal incoordination, which resulted in aspiration of secretions. Outcome is likely to be improved if collaboration between specialist surgical teams allows necessary procedures to be performed using the minimum number of anaesthetics. Examination of both the short and long term management of these children has stressed the importance of a multidisciplinary approach to their care.

Impact of Fontan operation on left ventricular size and contractility in tricuspid atresia

Left ventricular dimensions and contractility were determined by echocardiography in 33 patients with tricuspid atresia in 1985 and again in 1988. Eight patients remained palliated throughout the 3-year period; neither the left ventricular end-diastolic diameter (153 +/- 15% of normal vs. 157 +/- 19%, p = NS) nor a load-independent index of contractility (rate-corrected velocity of shortening [VCFc]/end-systolic meridional stress [ESSM]) changed. Eleven patients underwent a Fontan operation during the study and were reevaluated at least 6 months after surgery; left ventricular dimension decreased (130 +/- 15% vs. 114 +/- 19%, p less than 0.001), and the contractility index VCFc/ESSM improved (p less than 0.05). Fourteen patients had undergone a Fontan operation 0.9-9.5 years (mean, 4.2 years) before initial examination in 1985. Over the 3-year period, left ventricular dimensions did not change (121 +/- 17% vs. 118 +/- 11%, p = NS), but the contractility index showed significant improvement (p less than 0.01). Eight additional patients were studied just before and after a Fontan operation to examine the early effects of surgery. Left ventricular dimensions decreased from 130 +/- 14% to 100 +/- 13% by 10 days p less than 0.001) with no further change at 2 months. An inappropriate degree of ventricular hypertrophy was observed in only the early postoperative period. Successful Fontan repair results in rapid reduction of left ventricular size, followed by regression of hypertrophy to a normal mass-to-volume ratio. Operating at more favorable dimensions and loading conditions results in an early increase in left ventricular contractility, which further improves in the medium term follow-up.

CHARGE association in two monozygous triplets

In an unusual set of triplets, two monozygous girls presented with CHARGE association. Dissimilar surgical management of identical cardiovascular lesions has resulted in a disparate effect on their clinical state. Their case poses interesting questions concerning how CHARGE association may develop.

Long-term results of homograft valves in extracardiac conduits

Between 1971 and 1986, 335 patients received various extracardiac valved conduits between one of the heart chambers and the pulmonary arteries. The group of patients who received aortic homograft conduits and survived the operation were analysed in detail. The age varied between 9 days and 18 years (mean 7.1 +/- 0.7 years), weight 2.4 kg-63.5 kg (mean 17.8 +/- 10.8 kg). The diameter of the conduit used was 10-30 mm (mean 20.8 mm). Multivariate analysis revealed a highly significant model (P less than 0.005) which showed that the time interval between harvesting and use of the homograft (P less than 0.02) and the earlier date of operation (P less than 0.05) were the major risk factors for obstruction. Homografts used within 3 weeks of harvesting had freedom from obstruction of 79% at 8 years; homografts used between 3-6 weeks had freedom from obstruction of only 55% at 8 years. Homografts used alone performed significantly better than those extended with woven Dacron tubes. At 10 years, 93% of homografts used alone were free of obstruction compared to 52% of homografts extended with a Dacron tube. We conclude that aortic homografts used within 3 weeks of harvesting provide a reasonably durable conduit for a period of 12 years. Longer storage, and extension of the homograft with a woven Dacron tube should be avoided.

The role of the priming fluid in the metabolic response to cardiopulmonary bypass in children of less than 15 kg body weight undergoing open-heart surgery

The major metabolic response to open-heart surgery using cardiopulmonary bypass has been shown in adults to be modified by the components of the pump priming fluid. This effect is likely to be more significant in children. Data on 29 children less than 15 kg body weight are presented. Patients were randomised to receive a prime containing one of three crystalloid priming fluids: 100% Hartmann's (H), 50% Hartmann's + 50% 5%-Dextrose (HD), or 100% Plasmalyte 148 (P). The remainder of the prime was CPD stored blood and the prime was buffered with sodium bicarbonate. Severe hyperglycaemia 22.4 +/- 1.3 mmol/l occurred during bypass in the HD group but moderate hyperglycaemia occurred in the other prime groups. Hyperlactataemia occurred in all prime groups during bypass and was highest in the H prime group at 3.9 +/- 0.4 mmol/l. These changes in intermediary metabolites were only partly explained by the crystalloid components of the priming fluid. A subsiduary study revealed the important contribution of CPD stored blood to those intermediary metabolite concentrations. Therefore, the well recognised changes in intermediary metabolites as components of the metabolic response to surgery, namely hyperglycaemia and hyperlactataemia were augmented by the composition of the priming fluids. In addition, CPD stored blood and the sodium bicarbonate buffer increased the sodium concentration of the prime to hypernatraemic levels in both the H and P groups which caused an increase in sodium concentration during bypass. Therefore important changes during bypass occur as a direct result of the individual components of the priming fluid. These changes may result in osmolal flux, hyperglycaemia and hyperlactataemia, all of which have been reported to be potentially harmful.

Doppler mapping of postoperative left atrioventricular valve regurgitation

Left atrioventricular valve regurgitation often occurs as a postoperative hemodynamic complication from repair of an atrioventricular septal defect. In this study, cross-sectional two-dimensional Doppler flow mapping of the left atrium was used to quantify postoperative regurgitant flow in 29 patients. Its severity and location was related to the shape of the three leaflets of the left component of the atrioventricular valve, especially to the size of the mural leaflet. To identify which leaflet configuration was likely to cause regurgitation, the position of the leaflets was obtained from the parasternal short-axis view and the angular size of the mural leaflet expressed in degrees of an arc. Doppler mapping was performed in the apical four-chamber and the parasternal long-axis views, dividing the left atrium in nine squares in each. Regurgitation was defined as a jetlike systolic downstroke of the Doppler frequency shift in early systole. The angular size of the mural leaflet varied from 38 to 144 degrees (mean 86 +/- 36 SD). Massive regurgitation (six to nine sites) was encountered in seven patients, five with a mural leaflet size of over 110 degrees, one with mural leaflet size between 70 and 110 degrees, and one with a mural leaflet size of under 70 degrees. No or minimal regurgitation was encountered in 10 patients, three having a mural leaflet size of 70 to 110 degrees and seven with a mural leaflet size of less than 70 degrees. These data suggest that massive regurgitation is encountered in patients with large mural leaflets, whereas patients with smaller mural leaflets tend to have no or mild regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgery for congenital abnormalities of the mitral valve at the Hospital for Sick Children, London from 1969-1983

The surgical management of congenital mitral valve (MV) anomalies remains controversial and complex. Valve repair has been said to be preferable to valve replacement. To assess the validity of this suggestion we have reviewed our experience of these procedures at The Hospital for Sick Children, Great Ormond Street, London from 1969-1983. In that time 48 patients have undergone surgery; in 23 repair was practicable (Group A) and in 25 replacement of the MV was required (Group B). Group A patients were slightly older than group B patients (5.9 +/- 1.0 years (SEM) vs 3.6 +/- 0.5 years). Björk Shiley valves were the predominant prosthesis used. Overall mortality was 33%, with 17% in Group A and 48% in Group B. Hospital mortality was 4.5% in Group A and 28% in Group B. Actuarial survival for Group A was 90% at 1 year, and 75% at 2 and 5 years; for Group B it was 52% at 1 and 2 years and 42% at 5 years. Mortality was significantly higher in those aged less than 5 years. Four patients in Group A have required re-operation, in 3 valve replacement was required; 2 of these died in hospital. One patient in Group B has required reoperation for valve-related thromboembolism. Three patients are awaiting replacement of calcified bioprostheses. These data support the concept that repair of MV should be performed where possible. The severity of the anomalies was greater in Group B and a rethink as to whether valve replacement is the best option for severe mitral stenosis in those aged less than 5 years seems indicated, in view of the very high mortality.

Left-ventricular cavity dimensions in children with normal and dilated hearts

Studies were carried out to find how left-ventricular length and length/diameter ratio relate to body size and degree of dilation. By use of M-mode and two-dimensional echocardiography, diastolic cavity long axis (Led), diastolic cavity diameter (Ded), systolic cavity long axis (Les), systolic cavity diameter (Des), fractional L shortening (SFL), and fractional D shortening (SFD) were measured in children, adolescents, and young adults between two and 23 years of age, with body-surface area (BSA) between 0.5 and 2.1 m2 and with a variety of volume loads and SFD values. In normal subjects, Led/Ded was about 1.9. Regardless of age and pathology (in this age range), Led correlated consistently with BSA (Led = 3.9 + 3.2 BSA), indicating that the long axis changes rather little with pathological dilation. A plot of Led/Ded vs BSA/D2ed (in m2/cm2) formed a straight-line relation: Led/Ded = 0.77 + 16.4 BSA/D2ed. Similar relations were found for end-systolic dimensions. End-systolic L/D ratio exceeded end-diastolic L/D ratio to a degree that depended on both end-diastolic L/D ratio and SFD:Les/Des = Led/Ded + (0.22 + 2.67 Led/Ded)(SFD)2. Relations like these may be useful in the interpretation of echocardiographic images. The results suggest that left-ventricular L/D ratio may be influenced by myocardial anisotropy (dominance of hoop over meridional fiber orientation tending to promote prolate shape especially during systole) and external factors that antagonize extension of the long axis.