J.Jpn. Surg. Soc.. 53(1): 44-47, 1952
宿題報告
Progress in the Field of Cardiovascular Surgery : A Review
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Consultant in Surgery with the Commission on Atomic Casualties National Research Council Warner Wells, M. D., F. A. C. S. |
That any of these problems are even capable of partial solution is dependent upon the introduction of intratracheal anesthesia, technical developments in the broader fields of thoracic and vascular surgery, and the courageous efforts and imagination of physicians and surgeons imbued with the spirit of experimentation.
Rehn' for the first time in 1869, demonstrated to the German Surgical Society that a wound of the heart could be repaired. His report was the more remarkable when we recall that Billroth, one of the outstanding surgeons of his day, stated, "The surgeon who would attempt to suture a wound of the heart would lose the respect of his colleagues''. Billroth's opinion was echood by Stephen Paget in a contemporary (1895) textbook on thoracic surgery when he observed that ''No new method or no new discovery can overcome the natural difficulties that attend of the heart''.
Rehn's example awakened an interest in the heart as a surgical accessible organ-with widespread repercussions.
Weil, in 1895, proposed reqioval of the pericardium in cases of constrictive pericarditis. His suggestion becamd a reality in 1913 when Rehn and Sauerbruch successfuly decorticated a heart held captive by scar.
Brentano, in 1899, inquired if a surgical procedure could be devised to enlarge heart valves stenosed by disease. His question was pursued by Doyen² (1913), Tuffier³ (1914), Cutler⁴ (1923), Murray, et al⁵ (1938), Smithy⁶ (1948), Harken⁷ (1948), Erock⁸ (1948), and Clover, et al⁹ (1950). Smithy himself was afflicted with an aortic insufficiency and stenosis caused by rheumatic fever and died while trying to perfect a technique to relieve stenotic heart valves. Clover and his group, profiting by the problems and errors of their predecessors, have recently reported experience with 106 cases of valvular stenosis with an operative mortality of 6.6 percent. Their technique and results will be discussed in greater detail.
The extra-cardiac approach to disease or anomaly causing vascular obstruction or shunt has attracted the attention of many workers. In 1938 Cross¹⁰ reported the firsts uccessful case of ligation of a patent ductus arteriosus. A short time later Crafoord, working independently, also achieved success in the correction of this anomaly. Cross's case involved a child otherwise free of disease. Bacterial endocarditis has been found to occur in at least twenty-five percent of persons with patent ductus arteriosus. That the bacterial endocarditiscould be cured by ligation of a patent dutus was first demonstrated in 1940 by Touroff and Vesell¹¹. Experience with ligation of patent ductus has indicated that complete division is necessary to prevent recurrence.
Coarctation of the aorta was the next rampart of cardiovascular disease to fall. In 1945 Gross and Hufnagel¹², and Crafoord and Nylin¹³ almost simultaneously resected a coarctated area of the aorta and rejoined the divided ends. The perfection of this operation projected the life expectancy well beyond the previous limit of 35 years and offered. these patients a chance for a normal life free from the dangers of hypertension, aortic rupture, aneurism, cerebral hemorrhage, and acute bacterial endocarditis. In cases where the aorta could not be rejoined the subclavian artery was used to bridge the gap, although Hallenbeck, et al²⁰ have recently indicated that subclavian-aortic anastomosis gives less good results than primary aortic anastomosis,
The cyanotic patient suffering with an insufficient flow of blood through the pulmonary bed (best illustrated in the tetralogy of Fallot) was the next challenge to the thoracic surgeon. The brilliant work of Helen Taussig, a pediatrician, Prompted her to suggest that in this complex creation of a shunt, amounting to a patent ductus arteriosus, might improve the pulmonary circulation. The results of experimental and clinical study culminated in the presentatson of a paper by Blalock and Taussig¹⁴ in 1945 which described the end-to-end anastomosis of a systemic artery (usually the innominate or subclavian) to one of the pulmonary arteries. Although this operation is only a shunt which in nowise corrects the abnormal cardiovascular structures, increse in exerciase tolerance and the relief of cyanosis and polycythemia has amply justified its use.
A year later (1946) Potts and his associates¹⁵ simplified Blalock's technique by literaly creating an artiflcial ductus arteriosus between the aorta and the pulmonary artery. Not only is Potts' prccedure easier to perform but the anastomosis can be achieved without even a temporary cessation in blood flow, and the sacrifice of a systemic artery is unnecessary.
The relative merits of the two procedures is still debatable. Both prccedures depend on an abnormal circulatory shunt for success. Patients with major systemic-pulmonary shunts have not been folloWed long enough to predict the ultimate ability of an already abnormal heart and vacular system to withstand the strain of artifici l arterio-venous fistula.
Clover, et al⁹ have approached the problem of cardiac obstruction from within the heart itself. By drawing on the experience of previos workers, (principally Tuffier and Brock) and by the application of techniques developed by themselves they have operated on fifteen cases of pulmonary stenosis (6 infundibular and 9 valvular) with two deaths; 66 cases of mitral stenosis with 4 deaths and 5 cases of aortic stenosis with 2 deaths. They claim that the initial results of a direct surgical approach are comparable to those obtained by shunt procedures and believe that the patients may achieve more permanent relief and a more certain future than could be expected from a surgicaly produced shunt. Again, it wil be impossible to judge the relative merits of the extra-cardiac against the intracardiac approach until more patients have been treated aed more time has elapsed.
Essentially, Clover has re-introduced and modified a technique described earlier by Brock. In both methods pulmonary obstruction is relieved by the actual removal of tissue from the stenosed pulmonic valve or an infuudibulum narrowed by muscular hypertrophy or fibrous change. Mitral stenosis is attacked by means of a sheathed knife introduced through a left auricular trap, so attached to the finger that digital guidance is possible.The relief of aortic stenosis is attempted by dilatatation of the aortic valve approached through the aorta or through the left ventricle. The technique is a modification of a method first successfuly employed by Tuffier in 1914, and since the valve margins are more likely to be involved than the cusps, separation of the adherent leaves results in a functioning valve that reduces regurgitation as well as stenosis. The use of the Brock valvulotome ended in the death of a patient because uncontrollable aortic regurgitation ensued.
Coronary unsufficiency is a major problem in America. Current therapeutic measures are of limited value. It is natural, therefore, that the surgeon's attention should be attracted to a problem which is imperfectly solved. Beck¹⁶ has pioneered in this field. As early as 1932 he reported experimeats in which he attempted to improve myocardiac blood supply by extraneous means. Adhesions were created between the heart and pericardial fat and skeletal muscle were imbedded in the myocardium in an effort to improve collateral circulation. Beck's results and the results of others working along similar lines have been equivocal.
Fauteux¹⁷ approached the problem in a different way. Taking a queue from the observation of Oppel, that ligation of a peripheral vein may have a salutory effect on the circulation of an obstructed limb, he occluded the coronary sinus in patients suffering with coronary insufficiency. The results have not been promising.
A recent experiment is worth mentioning. Vineberg and Niloff¹⁸, have shown experimentally that myocardial implantation of the left internal mammary artery improves coronary circulation sufficiently to withstand ligation of the left coronary artery. So far this work has been confined to animals. Clinical application is awaited with anticipation.
The relief of pain associated with coronary insufficiency is an old problem, and has been attacked by rhizotomy (anterior and posterior), posterior root section, pericoronary neurectomy, and varying degrees of sympathectomy. Jonnesco and Leriche have been prominent advocates for the latter. Recent experience in this direction is capably summarized by Evens, et al¹⁹, who believe that partial or imperfect success with sympathectomy in the past has resulted from a failure to appreciate the precise sympathetic innervation of the heart. They have operated on 10 patients with severe or intractable anginal pain and claim that resection of the first, second, third, and fourth sympathetic ganglia can be expected to give relief when performed on the side to which the pain is referred. Best results are obtained when the ganglia are resectecl bilaterally. Evidence suggests that sympathetic denervation may even improve coronary circulation by relaxing the coronary vessels.
Cardiac surgery has made rapid strides in the last half century. Technical ingenuity has reached such a state of perfection that more and more cardiac problems formerly left to the internist are inviting the attention of the surgeon. That improvement is possible and progress continuous is due to a better appreciation of cardiovascular physiology and pathology, and to the refinements in anesthesia.
The necessity for expert anaesthesia cannot be too strongly emphasized to the surgeon who would engage in the practice of cardiovascular surgery. A warning expressed by Potts is worthy of repetition : "The rather severe grades of anoxemia alow these patients a narrow margin of safety over which an expert anaesthetist must carry them. Without the services of a well-trained anaesthetist, capable of giving intratracheal anaesthesia, resourcefulness in emergencies and conscious of the significarce of the slightest change in pulse, respiration, and blood pressure, the mortality will rise appreciably. In no operation (or field of surgery) is the work of the anaesthetist more important". (author's abstract)
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