Considerations in the surgical management of infantile coarctation of aorta

The results of a recent 5 year experience with resection of coarctation of the aorta in infants less than 1 year of age are compared with those of an earlier series from the same institution. The significant improvement in mortality and morbidity statistics is attributed to modifications in operative and postoperative care. Operative mortality has decreased from 38 to 17 percent and the incidence rate of significant restenosis has diminished from 60 to 33 percent. It is suggested that in patients with large associated intracardiac shunt banding of the main pulmonary artery should be performed before resection of the coarctation. Three of five patients have survived procedures performed in this sequence. Microsurgical techniques and careful approximation of the aortic lumen with interrupted sutures are the major factors responsible for the reduced incidence of recoarctation. Prolonged ventilatory support postoperatively with the occasional addition of controlled positive airway pressure and continued aggressive medical therapy for heart failure are recommended.

Cardiovascular malformation in infant deaths. 10-year clinical and epidemiological study

The infant mortality from cardiovascular malformations in a region with a population of 2 million inhabitants during a 10-year period has been studied. The study involved validation of the diagnoses and judgement whether the cardiovascular malformation was the dominating or a contributing cause of death. It is shown that the incidence of fatal cardiovascular malformations is probably overestimated in the official death statistics. Evaluation of the clinical findings and necropsy reports are important aids in obtaining more reliable figures of the incidence. The rate of referral of infants with cardiovascular malformations has increased during the period of this study, so that the number of operable lesions not referred has decreased. The infant mortality rate, found in this study, of 1.33 per 1000 liveborn babies constitutes about 20 per cent of all liveborn infants with cardiovascular malformations. The most common lesions found in those who died belonged to the group constituting the hypoplastic left heart syndrome. The proportion of this type of malformation, about 20 per cent of all those dying, is higher than in other similar studies. This difference can probably be explained by variations in selection and classification.

[Total transposition of the great vessels: Surgical treatment]

One hundred nine cases of complete transposition of great vessels alone or associated to other abnormalities are presented. In 91 cases a palliative treatment is given and in 18 cases there is a total correction done, depending upon the technique. Surgical indication and the technique used in every case is commented, making special reference to transpositions with ductus arteriosus or associated to coarctation of the aorta. In the 18 cases where we have done a total correction, we comment the surgical procedure of one of them who had a subpulmonary stenosis of the fibromuscular type, which we resolved through left ventriculotomy done on the apex of the ventricle and resecting the stenosis with an electroscalpel, which is a technique we have devised.

The surgical treatment of coarctation of the aorta

Patients with coarctation of the aorta have a significantly decreased life expectancy. Surgical correction is curative and involves a low mortality rate which increases with coexisting cardiovascular abnormalities. In our series, there were no operative deaths in patients with pure coarctation of the aorta. Age is an important factor and postoperative complications were more frequent in older patients. Re section of the narrowed area with end-to-end anastomosis is the technique of choice. If theis is not possible, a Dacron tube is a good alternative. Early diagnosis and early intervention are of utmost importance, even in asymptomatic patients.

Coarctation of the aorta. Longitudinal assessment of operated patients

One hundred and ninety patients over the age of two operated upon for coarctation of the aorta from 1957 to 1972 at one institution were followed for one to 15.5 years (mean, 6.6 years). There were eleven cardiovascular deaths in the follow-up period. The mean age at death was 32.5 years. Two-thirds of the patients had an associated cardiovascular anomaly; 74 had coexistent aortic valve disease, and 19 had mitral stenosis or insufficiency. Five patients had a significant central nervous system event in the late postoperative period. Left ventricular hypertrophy by electrocardiogram was noted in 45, and 72 had radiographic left ventricular hypertrophy. A significant persistent or residual hemodynamic abnormality, either congenital heart disease, residual coarctation or persistent diastolic hypertension, could account for the residual electrocardiographic or radiographic abnormality. The data indicate that this population requires continuing care despite correction of the coarctation.

Coarctation of the aorta with congenital mitral regurgitation

Among 861 infants and children with coarctation of the aorta examined between 1950 and 1973, inclusive, 18 (2.1%) also had congenital mitral regurgitation (MR).

Resection of the coarctation of the aorta was performed in 16 of these 18 patients (89%). There were three operative deaths early in the series, giving a total mortality rate of 18% since 1950. Over the past decade, mortality in this group has been reduced to zero. Mitral valve replacement was performed following resection of the coarctation in 2/13 patients (13%), both successfully. The follow-up of the 13 postoperative patients and the two who have not undergone surgery has ranged from 5 to 18 years, with a median of nine years. At the last examination, an appreciable pressure gradient persisted between the right arm and the legs in 4/15 patients (27%). Weight remained below the third percentile in none. The clinical picture of congestive heart failure was present in none, but significant cardiomegaly was found radiologically in 11/15 (73%) and the electrocardiogram remained abnormal in 8/15 (53%). Over the period of follow-up, the MR became clinically worse in 4/15 patients (27%), remained unchanged in 7/15 (47%), and improved following resection of the coarctation in 4/15 patients (27%).

The pathologic anatomy of congenital MR associated with coarctation of the aorta was reviewed and classified. Two unique cases were presented — rupture of chordae tendineae and perforation of the posterior leaflet, both apparently congenital. When mitral surgery becomes necessary, an understanding of the pathologic anatomy of congenital MR may well make it possible to avoid mitral valve replacement in selected cases.

Natural history of coarctation of the aorta

With the increasing number of subjects with coarctation of the aorta having operations, its natural history becomes more difficult to determine. The expectation of life has been calculated by two quite independent methods: (1) from 304 reported necropsies, and (2) from 22 deaths among 161 subjects followed for 716 patient-years. These were mostly patients rather than unselected school-children, but many were quite free from symptoms and were sent only because a murmur was heard on examination. Knowing how long they had been under observation, mortality rates could be calculated for each decade. They rise gradually but not very regularly, from 1.6 per cent in the first two decades to 6.7 per cent per annum in the sixth and later decades. The two methods give results in close agreement, closer than could be expected considering the relatively small numbers of patients and patient-years. The percentages of deaths at the end of each decade found by the two methods never differ by more than +/-4 per cent and are often much closer. Of those surviving the serious hazards of the first one or two years, 25 per cent die before they reach 20, 50 per cent by 32, 75 per cent by 46, and 90 per cent by 58 years. The arithmetical mean of the ages of death is 34 years instead of 71 years as normally. These means, however, hide a very wide range, with standard deviations of at least +/-15 per cent. For coarctation the median is 31 years and the mode is widely spread through the second to fifth decades rather than closely clustered round a point. This poor outlook makes an operative mortality in the region of 5 per cent a small price to pay for the greatly increased security afterwards. We do not yet know how much the risk of bacterial endocarditis or of intracranial haemorrhage will be reduced in the long run because there may be bicuspid aortic valves or intracranial berry aneurysms. The exact incidence of subacute bacterial endocarditis is uncertain, somewhere between 0.6 (from necropsy series) and 1.3 per cent per annum in clinical series. The range was similar for persistent ductus arteriosus, but paradoxically 1.5 for the necropsy series and 0.5 for the clinical series. Clearly the incidence is high in all the four malformations shown in Table 5, about 0.9+/-0.4 per cent per annum.

Coarctation of the aorta

In a series of 70 patients who had surgical correction of coarctation of the aorta between 1952 and 1969, the operative mortality was 7% and the complication rate was 14%. The mortality was particularly high in adult males over 30, with pre-operative evidence of left ventricular ischaemia. Simple surgical procedures had satisfactory results, but the use of prostheses carried a high risk, and turning down the left subclavian artery failed to lower the blood pressure. The blood pressure score fell by 68% after operation, and by a further 8% following discharge from hospital. This result was maintained up to 17 years after operation, and may be expected in all groups of patients.