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HYPERTROPHIC INFUNDIBULAR STENOSIS COMPLICATING SIMPLE PULMONARY VALVE STENOSIS

1959; BMJ; Volume: 21; Issue: 3 Linguagem: Inglês

10.1136/hrt.21.3.429

1468-201X

Alan M. Johnson,

Cardiac tumors and thrombi

Pulmonary valvotomy by the closed transventricular technique was introduced as an alternative to the Blalock-Taussig operation in Fallot 's tetralogy (Brock, 1948) and for relief of pulmonary stenosis in the presence of a closed ventricular septum (Brock and Campbell, 1950).In Fallot's tetralogy, at least until closure of the ventricular septal defect became feasible, some residual pulmonary stenosis was considered desirable.With a normal aortic root, however, complete relief of the stenosis was sought.It was soon found that this could not always be achieved at operation and for this three main reasons have been suggested.Kirklin et al. (1953), reporting twelve cases of transventricular pulmonary valvotomy, discussed the possibility that right ventricular hypertrophy might result in secondary stenosis in the infundi- bular region.Brock (1955), in an account of control mechanisms in the outflow tract of the right ventricle following a careful study extending over seven years, described and illustrated with pressure records secondary infundibular stenosis after pulmonary valvotomy.He discussed two factors responsible for this, the first mechanical, particularly in the region of the greatly enlarged crista supraventricularis, the second an exaggeration of the infundibular muscle tonus that normally functions to support the pulmonary valve ring.He suggested that, when this condition prevented complete relief of right ventricular hypertension, even a partial relief might suffice to allow regression of right ventricular hypertrophy and thus of secondary infundibular obstruction.Comparing their results of transventricular pulmonary valvotomy and ofthe open procedure Swan et al. (1954) expressed the view that inadequate valvotomy was the usual cause of failure to reduce right ventricular pressure with the closed technique.They contrasted the complete relief obtained in every one of five open operations in which they performed pulmonary valvotomy through the pulmonary artery, using hypothermia, and concluded that hypertrophy of the right ventricle was not a cause of outflow obstruction.The same group, however, found later that open valvotomy did not always completely remove the systolic gradient between right ventricle and pulmonary artery (Blount et al., 1957) and agreed that this was sometimes due to infundibular obstruction which, they observed, was capable of regression.Campbell and Brock (1955) suggested a third explanation of residual stenosis, namely that the valve ring itself and the outflow tract were small.They noted that, in spite of a high residual gradient following valvotomy, the clinical improve- ment and the diminution of right ventricular strain were better than they had expected.In one such case the right ventricular pressure was found to have fallen further at recatheterization a year after operation.McGoon and Kirklin (1958) have reported further experience with transventricular and open pulmonary valvotomy.They found that, in some patients, infundibular stenosis demonstrated by catheterization within a few weeks of operation had regressed completely twelve to eighteen months later.The existence of infundibular obstruction after valvotomy appeared to add to the hazards of the post-operative period.