Biomedical subjects
Publications and source records attributed to D F Dickinson.
A double outlet right ventricle was diagnosed in a 10 week old infant, in whom the ventricular septum was intact at the time of presentation. A large aneurysm of a membranous septal remnant was present, and this appears to be the first recorded instance of closure of a malalignment ventricular septal defect by such a mechanism.
Twenty three morphological specimens of truncus arteriosus were examined for evidence of stenosis of the semilunar valve. One third showed good evidence of stenosis as judged by careful measurement of the valve orifice, the valve ring, and the maximum diameter of the truncus. Correlation with measured pressure gradients was poor, but angiography and cross sectional echocardiography were better predictors of stenosis. Stenosis was invariably associated with cusp dysplasia and was more common in valves with two or four cusps.
In 12 patients with ductus arteriosus a characteristic velocity pattern in the pulmonary artery was identified using pulsed Doppler echocardiography. This pattern, which was absent in 52 normal control subjects and 200 consecutive patients with cardiac lesions other than ductus, consisted of a pandiastolic velocity directed away from the transducer. This pattern is thought to represent the diastolic component of flow into the pulmonary tree which occurs as a result of the left to right shunt.
Discrete delicate fibromuscular structures crossing the cavity of the left ventricle were identified on morphological examination in 329 (48%) of 686 hearts from patients of all ages with congenital heart disease, acquired heart disease, or normal hearts. These structures were also present in 151 (95%) of 159 hearts from animals of six species. Cross sectional echocardiographic findings compatible with these structures were obtained in 39 (21.7%) of 179 children reviewed retrospectively and in three of 800 (0.4%) adults studied prospectively. These structures appear to be a normal anatomical finding.
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Between February, 1969, and March, 1980, 235 consecutive patients underwent repair of tetralogy of Fallot. Of these, 94 patients were less that 4 years of age, including 40 less than 2 years of age. Previous palliative procedures had been performed in 46 patients. Conservative technique to relieve the right ventricular outflow tract (RVOT) obstruction was employed in 194 patients; transannular approach was performed in the remaining 41. There were 18 hospital deaths (7.6%) and 3 late deaths. The early and late results were significantly related to the ratio of the right ventricular to left ventricular systolic peak pressure after repair. Until 1976, the age of patients of operation constituted an operative risk factor. Since 1977, none of the 17 infants who underwent operation died after the repair. In the overall series, the transannular approach to relieve the RVOT obstruction affected the early mortality and the late results. During the last 3 years, only 1 of the 12 patients who received an aortic homograft monocusp transannular gusset died in the hospital, and the 11 survivors were completely symptom free at follow-up.
Seventeen heart specimens with tetralogy of Fallot were studied to assess the anatomy of the ventricular septal defect and the disposition and potential vulnerability to surgical trauma of the atrioventricular conduction tissue. Eleven had defects of the perimembranous type. In the majority of these cases the non-branching and branching atrioventricular bundle lay posterior to the defect in a position unlikely to be damaged during closure of the defect. However, in one case, the non-branching bundle extended onto the rim of the defect and in a further 4 cases, other major components of the atrioventricular conduction tissue appeared vulnerable. Six ventricular septal defects were of the muscular outlet type and the atrioventricular conduction tissue did not appear vulnerable in any case of this type. Conclusive differentiation between perimembranous and muscular outlet defects was not always possible on gross morphological examination. It is suggested that the crest of the muscular septum and fibrous tissue in the posterior corner of the ventricular septal defect should be avoided during closure of the defect.
The clinical course and outcome of treatment for 322 consecutive neonates referred to a supraregional paediatric cardiac unit are reviewed. Two hundred and forty-eight (77%) had structural congenital cardiac defects. The remaining 74 (23%) presented with arrhythmia, nonstructural cardiorespiratory problems, or problems unrelated to the cardiovascular or respiratory system. Transposition of the great arteries and coarctation of the aorta were associated with a good prognosis. Infants with cyanotic cardiac defects associated with a low pulmonary blood flow who required early palliation were found to have a poorer outlook.
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Forty-four consecutive infants aged from 3 days to 10 months underwent repair of total anomalous pulmonary venous connection using deep hypothermia with circulatory arrest. There were eight (18%) early hospital deaths. Using multivariate analysis no significant association could be shown between early mortality and age or weight at operation, preoperative pulmonary or systemic pressure, and preoperative condition for patients undergoing operation during the most recent five year period. Late pulmonary venous obstruction developed in four (11%) of the survivors and all of these patients died.
We have reviewed data on all patients born between 1960 and 1969 and registered in the Liverpool Registry of Congenital Malformations as having congenital heart disease. There were 385 with a ventricular septal defect as their sole or main cardiac lesion. Analysis of the available follow-up data showed that 50 of these were subsequently assigned in other diagnostic categories and a further 41 failed to fulfil our diagnostic criteria for a ventricular septal defect, leaving 294 patients for study. In view of the high incidence of small defects in asymptomatic infants and children not subjected to cardiac catheterisation, clinical criteria for the acceptance of the diagnosis were defined and 190 patients were included on these grounds alone. The clinical course, associated cardiac and non-cardiac defects, and surgical implications were analysed. The majority of defects were small and 31% closed spontaneously. Fifty per cent of the deaths in infancy were unrelated to the ventricular septal defect. We estimate that by present criteria only 15% of an unselected population of patients with a ventricular septal defect are likely to require surgical treatment.
Among 160 480 children born alive between 1960 and 1969 in Liverpool, 884 patients with structural congenital heart disease were identified. Data on these patients have been reviewed in order to estimate the number likely to need cardiac surgery during childhood and adolescence. Though only 33.9% of patients had surgery, we estimate that if current policies for management were followed, 475 (53.7%) patients would not require surgery. Extrapolation of this data suggests that each year in England and Wales approximately 830 infants (1383 per million livebirths) will require cardiac surgery within the first year of life and a further 1424 operations (2374 per million livebirths) will be required in later childhood or adolescence. No attempt has been made to estimate the number of operations for congenital heart disease which may prove necessary in adult life.
The early and late results of intracardiac repair of 175 cases of tetralogy of Fallot during the period 1969 to 76 are reviewed. Overall hospital mortality was 8%, with a 5% mortality in patients over 2 years of age. Late mortality was 1%. Both early and late mortality and morbidity were related to the right ventricular to left ventricular peak systolic pressure ratio measured at the end of the operation. During the eight year period, a fall in mortality from 37 to 15% was recorded in patients less than 2 years of age. As a result of the experience gained during this period, we have now adopted a more active policy towards reconstruction of the right ventricular outflow tract while remaining aware of the potential problems of pulmonary regurgitation.
Between January 1974 and November 1980, 13 symptomatic infants under 1 year of age with persistent truncus arteriosus type I or II underwent surgery. Pulmonary artery banding was performed in 10 cases, with five deaths. Among the survivors, one developed severe pulmonary vascular disease and only two underwent late intracardiac repair. Primary total correction was performed in three infants and all are well, though one required conduit replacement five and a half years after the initial procedure. Recently, antibiotic sterilised homograft conduits, rather than heterografts, have been preferred as extracardiac conduits in infancy. Early intracardiac repair followed, if necessary, by later conduit replacement appears to have significant advantages over "conventional" pulmonary artery banding and late total correction. Concern remains on the treatment of choice in infants under 3 months of age.
Ten patients between 8 months and 9 years of age (average 4.3 years) underwent surgical relief of coarctation of the aorta by the technique of left subclavian flap aortoplasty. Before operation, nine patients had systolic hypertension in the upper extremity (average 145 mm Hg) and all had a significant pressure gradient across the coarctated aortic segment (average 45 mm Hg). The hospital and late mortality were zero. The follow-up over 7 years has shown complete relief of the coarctation and no ischemic impairment or functional limitation of the left upper extremity. The blood pressure returned to normal in all patients. Hemodynamic and angiographic studies, performed in one case, demonstrated adequate growth of the repaired segment and absence of a pressure gradient across the previously narrowed area. The time interval between the peak of the femoral pulse and the dicrotic notch of the carotid pulse, recorded postoperatively, was normal. We consider the left subclavian flap technique to be the operation of choice in infancy and also in older children, whenever the anatomic configuration of the coarctation suggests that subsequent growth would be severely restricted if other techniques were used.
Eleven children with coarctation of the aorta were investigated before and after surgical treatment, using simultaneous indirect carotid and femoral pulse wave tracing. The timing of the onset of the femoral pulse in the children with coarctation, both before and after operation, did not differ significantly from normal. However, the time interval between the peak of the femoral pulse and the dicrotic notch of the carotid pulse was significantly shorter than normal in the children with coarctation before operation. After operation, the peak femoral to carotid dicrotic notch time interval was restored to normal. It is suggested that this simple non-invasive test might be of value in the long-term follow-up of patients after operation for coarctation of the aorta, particularly in those undergoing operation early in childhood, to detect residual or recurrent coarctation.
38 children were assessed 22 months to 6 years after open heart surgery using circulatory arrest with deep hypothermia. The mean IQ of the group was 99.2 (SD 19.5). No correlation was found between IQ and the age or weight at operation or the duration of circulatory arrest. The results suggest that the technique gives effective protection to the brain during periods of circulatory arrest for up to 60 minutes.