Pulmonary Valvotomy and Infundibulectomy

Obstruction to the outflow of the right ventricle may be at the pulmonary valve, the infundibular region, or both, and may be associated with defects in the septa.The normal and pathological anatomy of this area has been fully described by Brock (1957), and various surgical techniques have been suggested and practised for dividing the valve or relieving the infundibular stenosis.(1) Transventricular approach using a valvotome and splitter to open the valve and a punch to remove the infundibular thickening-with intact circulation (Sellors, 1948;Brock, 1948).(2) Transarterial approach using a valvotome to cut the valve-with intact circulation (Potts et al., 1950; S0ndergaard, 1952; Pettersen, 1954).(3) Open transarterial approach to the pulmonary valve with circulatory occlusion under hypothermia (Swan and Blount, 1956).(4) Open transarterial or transventricular approach to the valve and infundibular region using a cardio-pulmonary by-pass.Since 1954, 92 operations on the pulmonary valve and infundibulum have been performed at the Royal Liverpool Children's Hospital and Broadgreen Hospital, and the experience with these forms the basis of the subsequent observations.In the first 16 cases attempts were made to divide the valve through the ventricle or the pulmonary artery by means of a valvotome and stretcher.Although a complete division of the valve is possible by these methods, the disadvantage of either approach appeared to be that the valve is usually only partially divided and then stretched without further splitting.Manometric readings at this stage are somewhat difficult to interpret, and no confirmation of the resultant size of the opening was obtainable, either by sight or by finger pal- pation.The final result was often disappointing.In cases of pure pulmonary stenosis the right ventricular strain was often only partially relieved, and in cases with an associated ventricular septal defect and hypoplasia of the valve and pulmonary artery (tetrad of Fallot) the technical difficulties of dividing a miniature valve completely made the operation somewhat hazardous.This blind approach to the pulmonary valve was abandoned in favour of the direct visual exposure through the pulmonary artery and this has been used in 61 cases.Not only can the valve be seen directly and be accurately divided to the valve ring, but the finger can be passed through it into the right ventricle to ensure that there is no true infundibular stenosis.If such a stenosis is found, it can then be approached through the divided valve and the amount of material punched out controlled by finger palpation.Although this approach to an infundibular stenosis cannot be considered ideal, it is less disturbing to the heart than a transventricular approach and has the advantage that a tactile check of the residual opening can be made.There is little doubt that if the presence of an infundibular stenosis is demonstrated or suspected at the pre-operative catheterization, its complete removal can be guaranteed only by a direct visual approach.The time required for this together with any plastic repair on the outflow tract of the right ventricle demands, at present, the use of a cardiopulmonary by-pass.It has been argued that in pulmonary valve stenosis, the evidence obtained at pre-operative catheterization can not always guarantee that some degree of fibrotic infundibular stenosis or a small ventricular septal defect will not be found, and 472 on July 13,