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Coronary-bypass Surgery
137
THE LANCET Coronary-bypass Surgery As each
new
technical achievement in heart surgery
impact, a new wave of enthusiasm surges through patients and doctors alike. Sometimes the value of an operation is so obvious as not to require formal scientific proof. More commonly there are makes its
sides to the matter.’ At no time has heart surgery had such problems in validation as in aortocoronary bypass for coronary-artery disease. Surgery for atherosclerotic heart-disease is not new. O’SHAUGHNESSY’S omental grafts,2 BECK’s scarification of the epicardium to encourage collateral growth,3VINEBERG’S internal-mammary implantation into ischEemic heart tissue,4and other operations have held the stage for varying periods over more than thirty years. From a technical viewpoint, all these operations had an element of the blunderbuss, and only with later precise definition of the anatomy of coronary-artery disease by coronary arteriography 5,6 was a planned attack on discrete arterial stenosis and obstruction possible. Coronary endarterectomy7 was partly successful but was rapidly superseded by aorto-coronary venous bypass 8-the most convincing operation so far undertaken. The pioneer work at the Cleveland Clinic9 has led to many thousands of such operations in the United States, and the snowball is still increasing in size and The implications and potential remomentum. are immense. If the operation is shown percussions to be effective, then there will be demands for rapid expansion in heart investigation and surgical services; if no scientifically reputable appraisal of the results is made, then we are at risk of making many serious errors of judgment, both for the individual and in general policies. The bypass operation consists in construction of a channel for arterial blood from the aorta to the patent section of a coronary artery distal to a region of arterial disease. A section of the patient’s saphenous vein has been used most often, but lately the internal mammary artery has been shown to have advantages. Experienced surgeons are able to perform multiple bypass grafts to segments of the coronary tree as two
1. 2. 3. 4. 5.
Dexter, L., Werkö, L. (editors). Circulation, 1968, 38, suppl. no. 5. O’Shaughnessy, L. Br. J. Surg. 1936, 23, 665. Beck, C. S. Ann. Surg. 1935, 102, 901. Vineberg, A. M. Can. med. Ass. J. 1946, 55, 117. Sones, F. M., Shirey, E. K. Mod. Concepts cardiovasc. Dis. 1962, 31, 735.
6. 7.
Lancet, 1971, ii, 1297. Effler, D. B., Groves, L. K., Sones, F. M., Shirey, E. K. J. thorac. cardiovasc. Surg. 1964, 47, 98. 8. Favaloro, R. G., Effler, D. B., Groves, L. K., Sones, F. M., Fergusson, D. J. ibid. 1967, 54, 359. 9. Favoloro, R. G., Effler, D. B., Groves, L. K., Sheldon, W. C., Sones, F. M. Ann. thorac. Surg. 1970, 10, 97.
small as 2 mm. diameter. Under favourable circumstances, graft blood-flow can then be shown to be in the normal range.10,1l Angiograms likewise confirm a good channel from the arterial supply via the graft to the distal coronary vessels. From the mechanical point of view this is a remarkable achievement, and it is understandable that many major cardiac centres have gone straight ahead in organising a production line for thousands of such operations. The main clinical indication has been chronic
angina pectoris,9 although preinfarction syndromes (crescendo angina, unstable angina) and acute myocardial infarction have also been aggressively treated by urgent operation.12,13 But among some physicians there is unease and a sense of déjà vu.14 Previous operations have all had their moments - losing popularity as the placebo effect of having an operation " and the absence of proof fcr longterm benefit become evident. No previous operation, however, has had such tangible immediate success in re-establishing blood-flow, and the future role of the bypass graft in the management of ischaemic heart"
be assessed with all the care that is now for new pharmaceutical agents. The main claim for bypass surgery is relief of chronic angina refractory to medical treatment. Patients are selected on the basis of severity of symptoms and coronary arteriographic evidence of lesions amenable to bypass surgery. What does to medical treatment " mean ? When " refractory the relief of gauging symptoms by surgery, potential we need to recognise the very wide range in severity and frequency of angina in different individuals-no doubt related to different sorts of lesion but also depending on personality, occupation, pressure of work, fatigue, fluctuations in mood, ambient temperature, and so on. Obesity, hypertension, and poor general physical fitness are other contributing factors. Assiduous attention to all these, together with planned use of trinitrin and adequate doses of &bgr;blocking agents, can transform the symptom pattern of the patient with angina. A satisfactory state of affairs may be reached only after many months of patient and doctor commitment. Without prejudging the application of surgery to any given level of incapacity, it would seem essential to know that all conservative routes had been explored, if only to categorise the residual symptoms for which operation is proposed and against which relief by operation has to be matched. In estimating the postoperative relief from angina, we also need to recognise that amelioration of symptoms immediately disease
must
mandatory
10.
Flemma, R. J., Johnson, W. D., Lepley, D. Archs Surg. 1971, 103, 82.
Grondin, C. M., Lepage, G., Castonguay, Y. R., Meere, C., Grondin, P. Circulation, 1971, 44, 815. 12. Smullens, N. S., Wiener, L., Kasparian, H., Brest, A. N., Bacharach, B., Noble, P., Templeton, J. Y. J. thorac. cardiovasc. Surg. 1972, 64, 495. 13. Cohn, L. H., Gorlin, R., Herman, M. V., Collins, J. J. ibid. p. 503. 14. Friedberg, C. K. Cardiovasc. Res. Abstr. VI Wld Congr. Cardiol. 1970, p. 42. 11.
138
after operation should not be assumed to be cause and effect. Angina may well be less during relaxed convalescence, and only when the patient re-enters his normal life can the improvement be judged. This evaluation should desirably be backed by noninvasive objective measurements of exercise tolerance before and after operation-at comparable levels of general physical fitness. Careful study of the coronary lesion is also basic in a programme of bypass evaluation. Theoretically, the best symptomatic and physiological improvement after bypass surgery would be expected in a coronary stenosis severe enough to restrict flow at rest or at any given level of myocardial work while the distal arterial tree is of normal calibre and distribution. The myocardial cells should be able to make use of the increased oxygen supply-i.e., there should be no irreversible ischaemic change and no fibrous scars. Of course, the practical situation will often fall short of this ideal state, and it is important to document the precise situation in each patient operated on in order to help define what symptom relief may be expected of the operation in a given pathological situation. Within this area is the specialist problem of measuring coronary stenosis by two-plane angiography, grading the distal arterial distribution, and quantifying regional muscle function. Apart from linking the type of lesion with the potential for symptom relief in the individual, the pattern of disease shown by the arteriogram may be of key importance in the overall evaluation of bypass surgery. We must be able to compare the results of treatment with the natural history of disease. The natural history (in terms of mortality) of ischaemic disease depends to a large extent on the number of coronary arteries involved. In patients known to have two or three vessel disease, the risk of not surviving 5 years is said to be two or three times that in single-vessel disease.15,16 Singlevessel-disease prognosis may be as good as 90% survival at 5 years. 15 The mean mortality in stable angina pectoris irrespective of coronary-disease anatomy, given by the Framingham study, 17 is approximately 5*B, a year in men and rather less in women. In order to compare natural history with operative survival it would therefore seem necessary to match the outlook in operated patients with that in unoperated patients who have arteriographically similar disease distribution. In the most experienced centres perioperative mortality in patients with good ventricular function is a little under 5%,18 and in 5-yearmortality terms operation may well offer little to the patient with single-vessel disease and more to the patient with three-vessel disease. There is also a different prognostic pattern, in that operation implies Friesinger, G. C., Page, E. E., Ross, R. S. Trans. Ass. Am. Physns, 1970, 83, 78. 16. Moberg, C. H., Webster, J. S., Sones, F. M. Am. J. Cardiol. 1972, 29, 282. 17 Kannel, W. B., Feinleib, M. ibid. p. 154. 15.
18. Favoloro, R. G. Progr. Cardiol. 1972. 1, 205.
small but certain immediate mortality but, one hopes, a better mid and long term chance in selected patients. Before ideas harden on natural and operated survival, one thing needs to be clearly stated. We do not know the natural history of ischxmic disease with pharmacologically demonstrable long-term &bgr;blockade. It has already been suggested that clofibrate (’Atromid S ’) may lessen mortality, 19 possibly by an anti-arrhythmic action. &bgr;-blockade, with well-known anti-arrhythmic action, might therefore have a more powerful beneficial influence-not necessarily dependent on the degree to which angina is controlled. It is perhaps against survival with &bgr;-blockade that survival after operation should finally be matched. a
Bypass surgery in preinfarction syndromes (crescendo angina, unstable angina) and acute myocardial infarction is even more problematical. Logically, prevention of irreversible cell damage by emergency revascularisation should be a strong argument for operation. From North America there are impressive accounts of aborted evolution of ischaemic changes in various deteriorating situations.12 Proof of operative benefit is given by CoHN et al.,13who performed emergency saphenous-vein grafts in 8 patients with acute coronary occlusion; 7 of the incidents were a complication of coronary angiography. Grafts were functional within three hours of the known time of obstruction. Electrocardiographic abnormalities To achieve such were. reversed in 6 of 8 patients. results, surgical team, theatre, and arteriography have to be immediately available. This makes for real difficulties even in specialist centres, and especially if patients need to be transferred from a distance. The time after arterial occlusion during which revascularisation is profitable is not certain. It has been stated 20-22 that, if revascularisation can be performed within six hours of acute myocardial infarction, most of the ischaemic myocardium can be preserved. How far these observations in the laboratory animal apply to man, with his variably developed collateral circulation, is uncertain, but perhaps a longer period of ischemia might be sustained without irreversible damage. Again the risk of intervention has to be matched with natural hazards. Coronary arteriography has been performed in unstable angina with minimal risk,21 and surgical intervention has relieved angina with some evidence of reversal ofischaemic processes.12 This is in the hands of very experienced teams, however, and the risks of investigation and operation under these circumstances should not be underrated .23 The other half of the equation is the natural history of preinfarction 19. Newcastle and Edinburgh trials of Clofibrate in the treatment of ischæmic heart-disease. Br. med. J. 1971, iv, 767. 20. Favoloro, R. G., Effler, D. B., Cheanvechai, C., Quint, R. A., Sones, F. M. Am. J. Cardiol. 1971, 28, 598. 21. Cox, J. L., McLaughlin, V. W., Flowers, N. C., Horan, L. A. Am. Heart J. 1968, 76, 650. 22. Lie, J. T., Holley, K. E., Kampa, W. R., Tilus, J. L. Mayo Clin. Proc. 1971, 46, 319. 23. Fowler, N. O. Circulation, 1971, 44, 755.
139
myocardial infarction. Mortality in preinfarction syndromes has ranged from 5% to 40% 24-2-so no great debating skill is needed to make a plausible case for or against surgery. Selection of patients no doubt explains the highest mortality figures. Closest to the truth may be a recent community study in Edinburgh 28 which revealed only 3 sudden deaths in 167 patients. Frank myocardial infarction occurred in 14% of patients. Worldwide experience in coronary care suggests that the mortality from acute myocardial infarction not associated with cardiogenic shock should now be only a few percent,29 and it is difficult to see that surgery offers a better prognosis for life. When acute infarction is followed by profound circulation failure and shock, the usual mortality is about 90%, syndromes
and
and in this restricted group circulation-assist and emergency bypass surgery conceivably improve survival-rates slightly. 30,31 What is the likely future role of bypass operations ? On the broad front, symptomatic, pathophysiological, and prognostic improvement probably depend essentially on establishing a channel for normal
blood-flow, through an adequately patent distal arterial tree, to living myocardium capable of responding to renewed blood-supply. Such improvement seems unlikely to be maintained if the graft subsequently closes. The long-term patency of bypass grafts has not been fully documented. Early patency of approximately 90% has been reported 32 and patency
months to 1 year variously 33-36 as about 2 out of 3. Local deterioration quoted at the anastomotic site may be due to further arterial narrowing or occlusion proximal to the stenosis; to stenosis at the junction of graft and artery; or to subintimal fibroplasia and thrombosis of the graft. Early closure of grafts is associated particularly with low blood-flow observed at operation. 19,31 If symptomatic and other improvement depends on graft patency, and is merely a placebo effect or due to tissue death when the graft has closed, we may conclude that the future of bypass surgery hangs
largely
on
at
6
long-term patency.
Reinvestigation of
24. Wood, P. Br. med. J. 1961, i, 1779. 25. Resnik, W. H. Mod. Concepts cardiovasc. Dis. 1962, 31, 757. 26. Levy, H. Ann. intern. Med. 1956, 44, 1123. 27. Vakil, R. J. Am. J. Cardiol. 1964, 14, 55. 28. Fulton, M., Duncan, B., Lutz, W., Morrison, S. L., Donald, K. W., Kerr, F., Kirby, B. J., Julian, D. G., Oliver, M. F. Lancet, 1972, i, 860. 29. Lown, B., Shillingford, J. P. (editors). Am. J. Cardiol. 1967, 20, 449. 30. Lancet, 1972, ii, 1238. 31. Corday, E., Meerbaum, S., Lang, T. W. Am. J. Cardiol. 1972, 30, 575. 32. Morris, G. C., Reul, G. J., Howell, J. F., Crawford, E. S., Chapman, D. W., Beazley, H. L., Winters, W. L., Petersen, P. K., Lewiss, J. M. ibid. 1972, 29, 180. 33. Johnson, W. D., Aver, J. E., Tector, A. J. ibid. 1970, 26, 640. 34. Grondin, C. M., Lepage, G., Castonguay, Y. R., Meere, C., Grondin, P. Archs Surg. 1971, 103, 535. 35. Walker, J. A., Friedberg, H. D., Flemma, R. J., Johnson, W. D.
Circulation, 1971, 44, suppl. 2, p. 108. 36. Ross, D., Sutton, R., Dow, J., Gonzales-Lavin, L., Hendrix, G., Jefferson, K., McDonald, L., Petch, M., Smithen, C., Sowton, E. Br. med. J. 1972, ii, 644. 37. Johnson, BV. D., Lepley, D. W. J. thorac. cardiovasc. Surg. 1970, 39, 640.
coronary disease by arteriography, even if limited to selective graft injections, carries a small risk and therefore raises ethical questions. Yet not to have such information would be to exclude the most cogent arguments for surgery and, risk the lingering uncertainty experienced with femoro-popliteal bypass
grafts. 38 How should
advise
patients presenting today ? correctly haver over long-term prospects, practical policies must be decided while the results of clinical trials and follow-up are awaited. Nearly all such clinical decisions arise in patients with chronic stable angina, preinfarction and acuteinfarction surgery being comparatively small-scale exploration. In stable angina, before a decision on surgery, overall organic and psychological incapacity should be carefully assessed during a period of expert medical therapy. If angina remains an intolerable burden, then surgery offers the chance of rapid relief. Lesser degrees of incapacity must be weighed against the risks of investigation and surgery by the existing services. Until reputable follow-up data accumulate over the years there can be no complete idea of the effect of surgery on prognosis for life. Relief of symptoms is at present the overwhelming
Whilst
we
we must
consideration.
A New IN
Lymphoma Syndrome 1969, ROSAI and DORFMAN 39 tentatively
identified a disorder, "sinus histiocytosis with massive lymphadenopathy " (S.H.M.L.), which they thought was the same entity as had been described in single instances by AZOUNY and REED in 1966 40 and by VINCENT and MIERCORT in 1967.41 Apparently it was particularly common in Blacks, produced massive lymphadenopathy, had a characteristic and uniform microscopic picture, and followed a benign ROSAI and DORFMAN 42 have now described course. a further 30 cases, contributed by lymph-gland fanciers in many countries; the series includes cases described by DESTOMBES 43 in 1965 and 2 which came to necropsy. S.H.M.L. is evidently of worldwide but of the 30, 17 were in Blacks. It was distribution, predominantly a disease of the first decade of life, the youngest being 7 months old at onset. The oldest patient was aged 45 at onset. The sex distribution was equal, and lymphadenopathy was the common clinical feature, bilateral, painless, and often massive, all lymph-nodes being involved. When, as often happened, the node first involved was in the submandibular area, the late result tended to be a multinodular conglomerate mass. Axillary and was involvement inguinal usually slight and seen in 38. De Weese, J. A., Robb, C. G. Ann. Sung, 1971, 174, 346. 39. Rosai, J., Dorfman, R. F. Archs Path. 1969, 87, 63. 40. Azouny, F. J., Reed, R. J. New Engl. J. Med. 1966, 274, 928. 41. Vincent, T. N., Miercort, R. Penrose Cancer Hosp. Semin. 1967, 246. 42. Rosai, J., Dorfman, R. F. Cancer, 1972, 30, 1174. 43. Destombes, P. Bull. Soc. Path. exot. 1965, 58, 1169.
3,
THE LANCET Coronary-bypass Surgery As each
new
technical achievement in heart surgery
impact, a new wave of enthusiasm surges through patients and doctors alike. Sometimes the value of an operation is so obvious as not to require formal scientific proof. More commonly there are makes its
sides to the matter.’ At no time has heart surgery had such problems in validation as in aortocoronary bypass for coronary-artery disease. Surgery for atherosclerotic heart-disease is not new. O’SHAUGHNESSY’S omental grafts,2 BECK’s scarification of the epicardium to encourage collateral growth,3VINEBERG’S internal-mammary implantation into ischEemic heart tissue,4and other operations have held the stage for varying periods over more than thirty years. From a technical viewpoint, all these operations had an element of the blunderbuss, and only with later precise definition of the anatomy of coronary-artery disease by coronary arteriography 5,6 was a planned attack on discrete arterial stenosis and obstruction possible. Coronary endarterectomy7 was partly successful but was rapidly superseded by aorto-coronary venous bypass 8-the most convincing operation so far undertaken. The pioneer work at the Cleveland Clinic9 has led to many thousands of such operations in the United States, and the snowball is still increasing in size and The implications and potential remomentum. are immense. If the operation is shown percussions to be effective, then there will be demands for rapid expansion in heart investigation and surgical services; if no scientifically reputable appraisal of the results is made, then we are at risk of making many serious errors of judgment, both for the individual and in general policies. The bypass operation consists in construction of a channel for arterial blood from the aorta to the patent section of a coronary artery distal to a region of arterial disease. A section of the patient’s saphenous vein has been used most often, but lately the internal mammary artery has been shown to have advantages. Experienced surgeons are able to perform multiple bypass grafts to segments of the coronary tree as two
1. 2. 3. 4. 5.
Dexter, L., Werkö, L. (editors). Circulation, 1968, 38, suppl. no. 5. O’Shaughnessy, L. Br. J. Surg. 1936, 23, 665. Beck, C. S. Ann. Surg. 1935, 102, 901. Vineberg, A. M. Can. med. Ass. J. 1946, 55, 117. Sones, F. M., Shirey, E. K. Mod. Concepts cardiovasc. Dis. 1962, 31, 735.
6. 7.
Lancet, 1971, ii, 1297. Effler, D. B., Groves, L. K., Sones, F. M., Shirey, E. K. J. thorac. cardiovasc. Surg. 1964, 47, 98. 8. Favaloro, R. G., Effler, D. B., Groves, L. K., Sones, F. M., Fergusson, D. J. ibid. 1967, 54, 359. 9. Favoloro, R. G., Effler, D. B., Groves, L. K., Sheldon, W. C., Sones, F. M. Ann. thorac. Surg. 1970, 10, 97.
small as 2 mm. diameter. Under favourable circumstances, graft blood-flow can then be shown to be in the normal range.10,1l Angiograms likewise confirm a good channel from the arterial supply via the graft to the distal coronary vessels. From the mechanical point of view this is a remarkable achievement, and it is understandable that many major cardiac centres have gone straight ahead in organising a production line for thousands of such operations. The main clinical indication has been chronic
angina pectoris,9 although preinfarction syndromes (crescendo angina, unstable angina) and acute myocardial infarction have also been aggressively treated by urgent operation.12,13 But among some physicians there is unease and a sense of déjà vu.14 Previous operations have all had their moments - losing popularity as the placebo effect of having an operation " and the absence of proof fcr longterm benefit become evident. No previous operation, however, has had such tangible immediate success in re-establishing blood-flow, and the future role of the bypass graft in the management of ischaemic heart"
be assessed with all the care that is now for new pharmaceutical agents. The main claim for bypass surgery is relief of chronic angina refractory to medical treatment. Patients are selected on the basis of severity of symptoms and coronary arteriographic evidence of lesions amenable to bypass surgery. What does to medical treatment " mean ? When " refractory the relief of gauging symptoms by surgery, potential we need to recognise the very wide range in severity and frequency of angina in different individuals-no doubt related to different sorts of lesion but also depending on personality, occupation, pressure of work, fatigue, fluctuations in mood, ambient temperature, and so on. Obesity, hypertension, and poor general physical fitness are other contributing factors. Assiduous attention to all these, together with planned use of trinitrin and adequate doses of &bgr;blocking agents, can transform the symptom pattern of the patient with angina. A satisfactory state of affairs may be reached only after many months of patient and doctor commitment. Without prejudging the application of surgery to any given level of incapacity, it would seem essential to know that all conservative routes had been explored, if only to categorise the residual symptoms for which operation is proposed and against which relief by operation has to be matched. In estimating the postoperative relief from angina, we also need to recognise that amelioration of symptoms immediately disease
must
mandatory
10.
Flemma, R. J., Johnson, W. D., Lepley, D. Archs Surg. 1971, 103, 82.
Grondin, C. M., Lepage, G., Castonguay, Y. R., Meere, C., Grondin, P. Circulation, 1971, 44, 815. 12. Smullens, N. S., Wiener, L., Kasparian, H., Brest, A. N., Bacharach, B., Noble, P., Templeton, J. Y. J. thorac. cardiovasc. Surg. 1972, 64, 495. 13. Cohn, L. H., Gorlin, R., Herman, M. V., Collins, J. J. ibid. p. 503. 14. Friedberg, C. K. Cardiovasc. Res. Abstr. VI Wld Congr. Cardiol. 1970, p. 42. 11.
138
after operation should not be assumed to be cause and effect. Angina may well be less during relaxed convalescence, and only when the patient re-enters his normal life can the improvement be judged. This evaluation should desirably be backed by noninvasive objective measurements of exercise tolerance before and after operation-at comparable levels of general physical fitness. Careful study of the coronary lesion is also basic in a programme of bypass evaluation. Theoretically, the best symptomatic and physiological improvement after bypass surgery would be expected in a coronary stenosis severe enough to restrict flow at rest or at any given level of myocardial work while the distal arterial tree is of normal calibre and distribution. The myocardial cells should be able to make use of the increased oxygen supply-i.e., there should be no irreversible ischaemic change and no fibrous scars. Of course, the practical situation will often fall short of this ideal state, and it is important to document the precise situation in each patient operated on in order to help define what symptom relief may be expected of the operation in a given pathological situation. Within this area is the specialist problem of measuring coronary stenosis by two-plane angiography, grading the distal arterial distribution, and quantifying regional muscle function. Apart from linking the type of lesion with the potential for symptom relief in the individual, the pattern of disease shown by the arteriogram may be of key importance in the overall evaluation of bypass surgery. We must be able to compare the results of treatment with the natural history of disease. The natural history (in terms of mortality) of ischaemic disease depends to a large extent on the number of coronary arteries involved. In patients known to have two or three vessel disease, the risk of not surviving 5 years is said to be two or three times that in single-vessel disease.15,16 Singlevessel-disease prognosis may be as good as 90% survival at 5 years. 15 The mean mortality in stable angina pectoris irrespective of coronary-disease anatomy, given by the Framingham study, 17 is approximately 5*B, a year in men and rather less in women. In order to compare natural history with operative survival it would therefore seem necessary to match the outlook in operated patients with that in unoperated patients who have arteriographically similar disease distribution. In the most experienced centres perioperative mortality in patients with good ventricular function is a little under 5%,18 and in 5-yearmortality terms operation may well offer little to the patient with single-vessel disease and more to the patient with three-vessel disease. There is also a different prognostic pattern, in that operation implies Friesinger, G. C., Page, E. E., Ross, R. S. Trans. Ass. Am. Physns, 1970, 83, 78. 16. Moberg, C. H., Webster, J. S., Sones, F. M. Am. J. Cardiol. 1972, 29, 282. 17 Kannel, W. B., Feinleib, M. ibid. p. 154. 15.
18. Favoloro, R. G. Progr. Cardiol. 1972. 1, 205.
small but certain immediate mortality but, one hopes, a better mid and long term chance in selected patients. Before ideas harden on natural and operated survival, one thing needs to be clearly stated. We do not know the natural history of ischxmic disease with pharmacologically demonstrable long-term &bgr;blockade. It has already been suggested that clofibrate (’Atromid S ’) may lessen mortality, 19 possibly by an anti-arrhythmic action. &bgr;-blockade, with well-known anti-arrhythmic action, might therefore have a more powerful beneficial influence-not necessarily dependent on the degree to which angina is controlled. It is perhaps against survival with &bgr;-blockade that survival after operation should finally be matched. a
Bypass surgery in preinfarction syndromes (crescendo angina, unstable angina) and acute myocardial infarction is even more problematical. Logically, prevention of irreversible cell damage by emergency revascularisation should be a strong argument for operation. From North America there are impressive accounts of aborted evolution of ischaemic changes in various deteriorating situations.12 Proof of operative benefit is given by CoHN et al.,13who performed emergency saphenous-vein grafts in 8 patients with acute coronary occlusion; 7 of the incidents were a complication of coronary angiography. Grafts were functional within three hours of the known time of obstruction. Electrocardiographic abnormalities To achieve such were. reversed in 6 of 8 patients. results, surgical team, theatre, and arteriography have to be immediately available. This makes for real difficulties even in specialist centres, and especially if patients need to be transferred from a distance. The time after arterial occlusion during which revascularisation is profitable is not certain. It has been stated 20-22 that, if revascularisation can be performed within six hours of acute myocardial infarction, most of the ischaemic myocardium can be preserved. How far these observations in the laboratory animal apply to man, with his variably developed collateral circulation, is uncertain, but perhaps a longer period of ischemia might be sustained without irreversible damage. Again the risk of intervention has to be matched with natural hazards. Coronary arteriography has been performed in unstable angina with minimal risk,21 and surgical intervention has relieved angina with some evidence of reversal ofischaemic processes.12 This is in the hands of very experienced teams, however, and the risks of investigation and operation under these circumstances should not be underrated .23 The other half of the equation is the natural history of preinfarction 19. Newcastle and Edinburgh trials of Clofibrate in the treatment of ischæmic heart-disease. Br. med. J. 1971, iv, 767. 20. Favoloro, R. G., Effler, D. B., Cheanvechai, C., Quint, R. A., Sones, F. M. Am. J. Cardiol. 1971, 28, 598. 21. Cox, J. L., McLaughlin, V. W., Flowers, N. C., Horan, L. A. Am. Heart J. 1968, 76, 650. 22. Lie, J. T., Holley, K. E., Kampa, W. R., Tilus, J. L. Mayo Clin. Proc. 1971, 46, 319. 23. Fowler, N. O. Circulation, 1971, 44, 755.
139
myocardial infarction. Mortality in preinfarction syndromes has ranged from 5% to 40% 24-2-so no great debating skill is needed to make a plausible case for or against surgery. Selection of patients no doubt explains the highest mortality figures. Closest to the truth may be a recent community study in Edinburgh 28 which revealed only 3 sudden deaths in 167 patients. Frank myocardial infarction occurred in 14% of patients. Worldwide experience in coronary care suggests that the mortality from acute myocardial infarction not associated with cardiogenic shock should now be only a few percent,29 and it is difficult to see that surgery offers a better prognosis for life. When acute infarction is followed by profound circulation failure and shock, the usual mortality is about 90%, syndromes
and
and in this restricted group circulation-assist and emergency bypass surgery conceivably improve survival-rates slightly. 30,31 What is the likely future role of bypass operations ? On the broad front, symptomatic, pathophysiological, and prognostic improvement probably depend essentially on establishing a channel for normal
blood-flow, through an adequately patent distal arterial tree, to living myocardium capable of responding to renewed blood-supply. Such improvement seems unlikely to be maintained if the graft subsequently closes. The long-term patency of bypass grafts has not been fully documented. Early patency of approximately 90% has been reported 32 and patency
months to 1 year variously 33-36 as about 2 out of 3. Local deterioration quoted at the anastomotic site may be due to further arterial narrowing or occlusion proximal to the stenosis; to stenosis at the junction of graft and artery; or to subintimal fibroplasia and thrombosis of the graft. Early closure of grafts is associated particularly with low blood-flow observed at operation. 19,31 If symptomatic and other improvement depends on graft patency, and is merely a placebo effect or due to tissue death when the graft has closed, we may conclude that the future of bypass surgery hangs
largely
on
at
6
long-term patency.
Reinvestigation of
24. Wood, P. Br. med. J. 1961, i, 1779. 25. Resnik, W. H. Mod. Concepts cardiovasc. Dis. 1962, 31, 757. 26. Levy, H. Ann. intern. Med. 1956, 44, 1123. 27. Vakil, R. J. Am. J. Cardiol. 1964, 14, 55. 28. Fulton, M., Duncan, B., Lutz, W., Morrison, S. L., Donald, K. W., Kerr, F., Kirby, B. J., Julian, D. G., Oliver, M. F. Lancet, 1972, i, 860. 29. Lown, B., Shillingford, J. P. (editors). Am. J. Cardiol. 1967, 20, 449. 30. Lancet, 1972, ii, 1238. 31. Corday, E., Meerbaum, S., Lang, T. W. Am. J. Cardiol. 1972, 30, 575. 32. Morris, G. C., Reul, G. J., Howell, J. F., Crawford, E. S., Chapman, D. W., Beazley, H. L., Winters, W. L., Petersen, P. K., Lewiss, J. M. ibid. 1972, 29, 180. 33. Johnson, W. D., Aver, J. E., Tector, A. J. ibid. 1970, 26, 640. 34. Grondin, C. M., Lepage, G., Castonguay, Y. R., Meere, C., Grondin, P. Archs Surg. 1971, 103, 535. 35. Walker, J. A., Friedberg, H. D., Flemma, R. J., Johnson, W. D.
Circulation, 1971, 44, suppl. 2, p. 108. 36. Ross, D., Sutton, R., Dow, J., Gonzales-Lavin, L., Hendrix, G., Jefferson, K., McDonald, L., Petch, M., Smithen, C., Sowton, E. Br. med. J. 1972, ii, 644. 37. Johnson, BV. D., Lepley, D. W. J. thorac. cardiovasc. Surg. 1970, 39, 640.
coronary disease by arteriography, even if limited to selective graft injections, carries a small risk and therefore raises ethical questions. Yet not to have such information would be to exclude the most cogent arguments for surgery and, risk the lingering uncertainty experienced with femoro-popliteal bypass
grafts. 38 How should
advise
patients presenting today ? correctly haver over long-term prospects, practical policies must be decided while the results of clinical trials and follow-up are awaited. Nearly all such clinical decisions arise in patients with chronic stable angina, preinfarction and acuteinfarction surgery being comparatively small-scale exploration. In stable angina, before a decision on surgery, overall organic and psychological incapacity should be carefully assessed during a period of expert medical therapy. If angina remains an intolerable burden, then surgery offers the chance of rapid relief. Lesser degrees of incapacity must be weighed against the risks of investigation and surgery by the existing services. Until reputable follow-up data accumulate over the years there can be no complete idea of the effect of surgery on prognosis for life. Relief of symptoms is at present the overwhelming
Whilst
we
we must
consideration.
A New IN
Lymphoma Syndrome 1969, ROSAI and DORFMAN 39 tentatively
identified a disorder, "sinus histiocytosis with massive lymphadenopathy " (S.H.M.L.), which they thought was the same entity as had been described in single instances by AZOUNY and REED in 1966 40 and by VINCENT and MIERCORT in 1967.41 Apparently it was particularly common in Blacks, produced massive lymphadenopathy, had a characteristic and uniform microscopic picture, and followed a benign ROSAI and DORFMAN 42 have now described course. a further 30 cases, contributed by lymph-gland fanciers in many countries; the series includes cases described by DESTOMBES 43 in 1965 and 2 which came to necropsy. S.H.M.L. is evidently of worldwide but of the 30, 17 were in Blacks. It was distribution, predominantly a disease of the first decade of life, the youngest being 7 months old at onset. The oldest patient was aged 45 at onset. The sex distribution was equal, and lymphadenopathy was the common clinical feature, bilateral, painless, and often massive, all lymph-nodes being involved. When, as often happened, the node first involved was in the submandibular area, the late result tended to be a multinodular conglomerate mass. Axillary and was involvement inguinal usually slight and seen in 38. De Weese, J. A., Robb, C. G. Ann. Sung, 1971, 174, 346. 39. Rosai, J., Dorfman, R. F. Archs Path. 1969, 87, 63. 40. Azouny, F. J., Reed, R. J. New Engl. J. Med. 1966, 274, 928. 41. Vincent, T. N., Miercort, R. Penrose Cancer Hosp. Semin. 1967, 246. 42. Rosai, J., Dorfman, R. F. Cancer, 1972, 30, 1174. 43. Destombes, P. Bull. Soc. Path. exot. 1965, 58, 1169.
3,