J.Jpn. Surg. Soc.. 59(8): 1213-1234, 1958

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DIRECT VISUAL OPERATION OF AORTIC STENOSIS WITH A CARDIOSCOPE

Surgery for aortic stenosis is still considerd difficult even under hypothermic conditions and with the use of artificial heart-lung apparatus. Before attempting surgical intervention on this valvular disease, preliminary studies of normal valvular movements in animals were carried out. Using the method of iutracardiac irrigation with physiologic saline, the movements of the aortic, mitral, pulmonary and tricuspid valves were recorded on films and the valvular movments were analysed.
The aortic valvular movements are as follows :
During the period of maximum ejection of blood, concomitant with dilatation of the aorta, the commissures open outward, the free edges of the valve leaflets remain tens forming a equilateral triangle and the surface of the cusps bulge toward the ventricle, thereby preventing occlusion of the coronary sinus. At diastole, There is an instantaneous slackening of the cusps and then apposition and closure of the valve is effected. During the period of valvular closure, the opposing edges of the cusps form a narrow ridge. Therefore, when commissurotomy is performed from the aortic lumen, the separated edges forming this narrow ridge cannot be distinguished unless the valve is a quiescent state and the possibility of incising the leaflets with resultant aortic insufficiency is exceedingly great.
In view of the extreme difficulty in producing valvular stenosis in animales, study of pulmonary stenosis in clinical cases was carried out as the stenotic condition is very similar to aortic stenosis. Furthermore, the stenotic condition of the pulmonary valve can be directly observed during open heart surgery. The stenotic character, mobility and state of commissural fusion were first filmed through a cardioscope with a vinyl-cap and then this record on film was compared with the appearence of the valve observed under direct vision through the incised ventricle. The results of this comparative study showed that it is possible to observe accurately the stenotic condition through the cardioscope.
Based upon the above observation, a cardioscope for observation and operation of aortic valve was deviced and its use was investigated. We found that for observation of the aortic valvular orifice and commissurotomy, maximum safety and certainly was provided with trans-ventricular mobilization of the commissures using a cardio scope with a serrat edged knife attachment without occluding the blood flow. Asid from these experiments, results of 67 operations for aortic stenosis which have been performed in our service up to the present were evaluated. Comparison of operative technics and prognosis of the patients showed that mobilization of commissures is frequently inadequated with the closed technic and the method of trans-aortic palpation and incision is full of danger. These disadvantages with the difficulty encountered in this surgical procedure under direct vision using the heart-lung apparatus demonstrated keenly the necessity of a safer and more reliable method of repairing the valvular orifice.
A surgical technic using the cardioscope for aortic valve incision which the author had deviced was there by investigated and has been performed in 7 patients with aortic stenosis or combined valvular diseases showing moderate calcification of the valve. Commissurotomy was successfully pertormed through direct cardioscopic visualization in all 7 cases. There was one postoperative death due to cerebral embolism, which could, I believe, have been prevented. The blood loss in these patients compared to that of similar operations using the heart-lung by-pass technic was less than half. Electrocardiographic observations showed no detremental changes and the intracardiac presure and ballistocardiogram indicated improvement in the postoperative period. No incidence of aortic insuffciency occurred and aggravation of cardiac function was not observed in any cases. This method was thereby judged to be relatively safe and reliable.
Summarizing the above, direct observation of the aortic valve from the aortic lumen, the mitral, tricuspid and pulmonary valves from the heart chambers were made in animals, recorded on films and valvular movements were analyzed. Dirct observation and similar procedures were also carried out in clinical cases of pulmonary stenosis and based on these studies commissurotomy has been successfully performed in patients with aortic stenosis through cardioscopic visualization.
We believe that this study is the first attempt of its kind.
(author's abstract)

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