- Email: [email protected]
Surgical Treatment of Mitral Stenosis
898
hands, for inadequate chemotherapy by unskilled people or by unrestricted purchase and self-administration will almost certainly increase the risks of infection by resistant organisms and reduce the benefit from masstreatment schemes, with further economic loss. The poorer countries will be considerably aided by the knowledge that is being accumulated by purposeful clinical trials, such as the Madras project. More such experiments are necessary; and the more favoured Western countries, with their money and technical skills, could offer more help than they have provided so far.
Surgical
Treatment of
Mitral Stenosis THE first
operations on the mitral valve were those CUTLER and LEVINEand SOUTTAR2 in the devised by 1920s, and from then on progress has been remarkable, particularly since the modem procedure was introduced.3-5 It soon became clear that the most satisfactory approach to the mitral valve was by means of a finger introduced through the left atrial appendage, and for the first few years all valvotomies were done by the surgeon’s finger in this way. But although the left atrial route is best for palpating the valve and determining its condition, the results of finger-fracture alone were often unsatisfactory, because the commissures could not be completely divided. So the next development was a cutting instrument introduced via the left atrium and guided into position by the surgeon’s finger. The fused valve cusps could then be divided more effectively, but it was often very hard to identify the exact site of the commissure, and a knife cut in the wrong place might well lead to disorganised valve function and serious incompetence. DUBOST6 therefore introduced mechanical splitting of the valve by a transatrial dilator, which had the advantage over the finger that no counter pressure from outside was needed to split a resistant valve, and its action was the same as the finger’s in that it stretched the valve until it gave at its weakest point, which was usually where the commissures were fused. Mr. LOGAN and Dr. TURNER, whose paper we publish this week, were dissatisfied with the atrial approach but impressed by the possibilities of the mechanical dilator; and in 1954 they began to use a transventricular dilator, guided into position by a finger in the left atrium. They review (p. 874) 438 patients who have undergone mitral valvotomy performed with the transventricular dilator. Since LOGAN introduced this technique, it has been widely used by surgeons in this country and -abroad; but this is the first large series described by the originators of the method, and an account of their experience has been awaited with keen interest by cardiac surgeons. This issue also includes a report by Mr. CRUM and Dr. TSAPOGAS of 50 consecutive mitral valvotomies performed in this way. Cutler, E. C., Levine, S. A. Bost. med. surg. J. 1923, 188, 1023. Souttar, H. S. Brit. med. J. 1925, ii, 603. Bailey, C. P. Dis. Chest. 1949, 15, 377. Harken, D. E., Ellis, L. B., Ware, P. F., Norman, L. P. New Engl. J. Med. 1948, 239, 801. 5. Baker, C., Brock, R. C., Campbell, M. Brit. med. J. 1950, i, 1283. 6. Dubost, C. Pr. méd. 1954, 62, 253. 1. 2. 3. 4.
The was
most
much
important finding was that the valvotomy thorough with the dilator, and the
more
in which division of both commissures was incomplete dropped from 26% to 11%. This should mean that re-stenosis of the valve will be considerably less common after transventricular dilation. As experience grew the dilator was used in more and more operations until it became the routine in almost every case. Valvotomy by the finger in the atrium was always tried first, but these preliminary attempts became more gentle as the series progressed. When there was clot in the atrium the dilator technique had a positive advantage in that manipulation of the valve could very often be much reduced, and the finger had to be inserted only once, thus decreasing the risk of liberating emboli. The instrument should have stops on it so that the maximum opening can be varied (most surgeons choose a maximum between 3- 5 and 5 cm.) and the ideal spread was provided by the instrument designed by 0. S. TUBBS.
proportion
of
cases
A criticism levelled against this technique is that it increases the risk of traumatic mitral incompetence, but in LOGAN and TURNER’S series there have been only 6 deaths from this cause out of 438 operations, as opposed to 4 deaths out of 388 in the pre-dilator series. LOGAN emphasises that a suitable mechanical stop on the dilator and steady dilation to avoid sudden rupture of the valve are important in avoiding traumatic incompetence. If the dilator completely divides one commissure and not the other, it is dangerous to dilate further because that could lead to rupture of the mitral ring with gross incompetence. Calcification of the valve is not a bar to the use of the instrument. LOGAN says that the exact position of the dilator in relation to the valve at the time of opening is unimportant since the valve will always split at its weakest point-namely, along the commissures. But CRUM and TSAPOGAS aimed to open the instrument in the line of the commissure. It seems reasonable to exert if possible the greatest pressure on the weakest point-where the commissures are fused-but if this cannot be accurately identified it is valuable to know that no harm will be done by deviating from this line.
mortality-rate in LOGAN and TURNER’S series is slightly higher (6-4%, compared with 5% in their predilator series), but against this must be balanced a considerably more efficient opening of the valve by the new technique. Calcification of the valve was not associated with a higher mortality; and figures for cerebral embolism were slightly lower. Moreover, ventricular fibrillation was not apparently a problem. The transventricular technique has shown itself to be one of the major advances in mitral surgery in recent years. The same results can be and are obtained by other operations with finger-knives or guillotines, but LOGAN’S method is the easiest to perform and probably the safest. The results of blind operations will hardly improve on the transventricular figures, and this operation is likely to remain the standard approach to mitral The
stenosis in this country for
some
time.
hands, for inadequate chemotherapy by unskilled people or by unrestricted purchase and self-administration will almost certainly increase the risks of infection by resistant organisms and reduce the benefit from masstreatment schemes, with further economic loss. The poorer countries will be considerably aided by the knowledge that is being accumulated by purposeful clinical trials, such as the Madras project. More such experiments are necessary; and the more favoured Western countries, with their money and technical skills, could offer more help than they have provided so far.
Surgical
Treatment of
Mitral Stenosis THE first
operations on the mitral valve were those CUTLER and LEVINEand SOUTTAR2 in the devised by 1920s, and from then on progress has been remarkable, particularly since the modem procedure was introduced.3-5 It soon became clear that the most satisfactory approach to the mitral valve was by means of a finger introduced through the left atrial appendage, and for the first few years all valvotomies were done by the surgeon’s finger in this way. But although the left atrial route is best for palpating the valve and determining its condition, the results of finger-fracture alone were often unsatisfactory, because the commissures could not be completely divided. So the next development was a cutting instrument introduced via the left atrium and guided into position by the surgeon’s finger. The fused valve cusps could then be divided more effectively, but it was often very hard to identify the exact site of the commissure, and a knife cut in the wrong place might well lead to disorganised valve function and serious incompetence. DUBOST6 therefore introduced mechanical splitting of the valve by a transatrial dilator, which had the advantage over the finger that no counter pressure from outside was needed to split a resistant valve, and its action was the same as the finger’s in that it stretched the valve until it gave at its weakest point, which was usually where the commissures were fused. Mr. LOGAN and Dr. TURNER, whose paper we publish this week, were dissatisfied with the atrial approach but impressed by the possibilities of the mechanical dilator; and in 1954 they began to use a transventricular dilator, guided into position by a finger in the left atrium. They review (p. 874) 438 patients who have undergone mitral valvotomy performed with the transventricular dilator. Since LOGAN introduced this technique, it has been widely used by surgeons in this country and -abroad; but this is the first large series described by the originators of the method, and an account of their experience has been awaited with keen interest by cardiac surgeons. This issue also includes a report by Mr. CRUM and Dr. TSAPOGAS of 50 consecutive mitral valvotomies performed in this way. Cutler, E. C., Levine, S. A. Bost. med. surg. J. 1923, 188, 1023. Souttar, H. S. Brit. med. J. 1925, ii, 603. Bailey, C. P. Dis. Chest. 1949, 15, 377. Harken, D. E., Ellis, L. B., Ware, P. F., Norman, L. P. New Engl. J. Med. 1948, 239, 801. 5. Baker, C., Brock, R. C., Campbell, M. Brit. med. J. 1950, i, 1283. 6. Dubost, C. Pr. méd. 1954, 62, 253. 1. 2. 3. 4.
The was
most
much
important finding was that the valvotomy thorough with the dilator, and the
more
in which division of both commissures was incomplete dropped from 26% to 11%. This should mean that re-stenosis of the valve will be considerably less common after transventricular dilation. As experience grew the dilator was used in more and more operations until it became the routine in almost every case. Valvotomy by the finger in the atrium was always tried first, but these preliminary attempts became more gentle as the series progressed. When there was clot in the atrium the dilator technique had a positive advantage in that manipulation of the valve could very often be much reduced, and the finger had to be inserted only once, thus decreasing the risk of liberating emboli. The instrument should have stops on it so that the maximum opening can be varied (most surgeons choose a maximum between 3- 5 and 5 cm.) and the ideal spread was provided by the instrument designed by 0. S. TUBBS.
proportion
of
cases
A criticism levelled against this technique is that it increases the risk of traumatic mitral incompetence, but in LOGAN and TURNER’S series there have been only 6 deaths from this cause out of 438 operations, as opposed to 4 deaths out of 388 in the pre-dilator series. LOGAN emphasises that a suitable mechanical stop on the dilator and steady dilation to avoid sudden rupture of the valve are important in avoiding traumatic incompetence. If the dilator completely divides one commissure and not the other, it is dangerous to dilate further because that could lead to rupture of the mitral ring with gross incompetence. Calcification of the valve is not a bar to the use of the instrument. LOGAN says that the exact position of the dilator in relation to the valve at the time of opening is unimportant since the valve will always split at its weakest point-namely, along the commissures. But CRUM and TSAPOGAS aimed to open the instrument in the line of the commissure. It seems reasonable to exert if possible the greatest pressure on the weakest point-where the commissures are fused-but if this cannot be accurately identified it is valuable to know that no harm will be done by deviating from this line.
mortality-rate in LOGAN and TURNER’S series is slightly higher (6-4%, compared with 5% in their predilator series), but against this must be balanced a considerably more efficient opening of the valve by the new technique. Calcification of the valve was not associated with a higher mortality; and figures for cerebral embolism were slightly lower. Moreover, ventricular fibrillation was not apparently a problem. The transventricular technique has shown itself to be one of the major advances in mitral surgery in recent years. The same results can be and are obtained by other operations with finger-knives or guillotines, but LOGAN’S method is the easiest to perform and probably the safest. The results of blind operations will hardly improve on the transventricular figures, and this operation is likely to remain the standard approach to mitral The
stenosis in this country for
some
time.