- Email: [email protected]
The Need to Know
The Need to Know Irwin J. Schatz. M.D., F.G.G.P. o
Sincere and honest physicians can only respond with respect and admiration to this latest information from the Cleveland Clinic. An in-hospital mortality of 1.2 percent for coronary bypass operations is a demonstration of superb care-surely due to an amalgam of efforts from which professional talents, interdisciplinary teamwork and administrative understanding have created an unsurpassed environment for successful open heart operations. Dr. Effier's comments on these data are precisely to the point: those of us involved directly in the care of patients who will undergo bypass procedures would profit by observing and learning what we can from the Cleveland Clinic group. In spite of this, however, should we expect to emulate these results? The answer, as of now, must be a qualified no, for the necessary descriptive information about the Cleveland Clinic cases is just not available to us. Are the patients whom we would consider for bypass operation comparable in a few, most, or all respects with those of Dr. EfHer and his associates? Details of their preoperative clinical status, angiographic characteristics, and hemodynamic parameters are necessary in order for us to conclude that we are dealing with similar groups of patients, and that therefore the goal of achieving an operative mortality rate of 1.2 percent is realistic. As was pointed out,1 if these operations are destined to become more prevalent, then progressively greater use should and must be made of local surgical resources. The need, then, is to know about the operative risks for coronary bypass procedure at the institutions at which most of our patients will be operated upon. Presumably, the bulk of these will be done at local community hospitals and not at highly specialized centers. The data from the Subcommittee for Coronary Disease2 show an overall mortality rate of 7.2-11.8 percent (exclusive of the Cleveland Clinic) in 1970, compiled from those groups responding to the questionnaires of the Committee. These figures are less than breathtaking; obviously they must be taken into account when considering the indications for operations. It is gratifying to learn from Dr. Effier's communication that at a number of community hospitals Professor of Internal ~Iedicine, University of \ledieaJ Center, Ann Arbor.
o Associate
i~an
82
~Iich
throughout the country the hospital mortality for bypass operations approaches that at the Cleveland Clinic. Hopefully, such expertise is contagious, and as a result, a generalized lowering of operative risks for these procedures will be forthcoming. Nevertheless, until such occurs, the practitioner faced with the problem of the patient with symptomatic coronary disease must decide on that therapy which in his opinion is most appropriate in his own local environment. A principal, but not sole, factor in that decision should be a consideration of the risk of dying at the time of, or shortly after the operation. In addition, however, other judgments must enter into this decision. Which patient is to be operated upon, and at what point during the course of the illness? Does the relief of pain after bypass surgery occur in more patients than what one might expect from a placebo, or a sham operation? Does coronary obstructive disease in the bypassed vessel progress more rapidly than it would under other, nonoperative methods of therapy? Does bypass increase or reduce the number and patency of available collaterals? Is it possible (or likely) that these operations relieve pain because they cause infarction? What is the actual incidence of myocardial damage after bypass? What is its significance? Finally, and perhaps most important, do these procedures improve prognosis for survival when properly compared to various forms of nonoperative treatment? In an ideal world, these answers would be available to us before we proposed therapy. Unfortunately, decisions about management often must be made on the basis of incomplete information. There is thus an overpowering need to accumulate objective data documenting the postoperative status of patients, for the assumption that coronary bypass is indicated because it is safe is both dangerous and illogical. Such a conclusion implies that the immediate answer to proximal coronary artery disease is at hand, and that success awaits only the perfection of our coronary angiographic and operative techniques, and the application of meticulous, interdisciplinary intra- and postoperative care. Although this may be the case, there is now insufficient acceptable evidence to support such a contention. Clearly then, it is incumbent upon all who advise and perform these CHEST, VOL. 63, NO.1, JANUARY, 1973
83
AND THE WAR GOES ON
operations to attempt to obtain answers to'some of the above questions. An example of such recently acquired data are the reports from the Johns Hopkins Hospital Group.3.5 Sixty-eight of 153 patients were restudied several months after bypass operation. The preoperative clinical, angiographic and hemodynamic characteristics of those undergoing subsequent investigations were similar to those who were not studied in the postoperative period. Of these 68 patients, 44 had significant localized postoperative electrocardiographic changes consistent with myocardial injury or damage. New and significant Q waves developed in nine; of these, five lost a portion of their native circulation and four showed reduced contractile segmental motion on ventriculography. Of the 20 patients with significant ST segment changes, 18 had either a loss of native circulation, a reduction in segmental motion, or both. Of 15 with evolving T wave changes postoperatively, 12 had reduced segmental motion. Thus, of 44 patients who had electrocardiographic changes, in 37 there was objective evidence suggesting myocardial damage postoperatively. Obstruction of at least a segment of a previously patent coronary artery was found in 46 of 153 of native vascular beds studied. In those vessels in which a bypass graft had not been placed, the incidence of new total occlusion was 23 percent (15 of 66). When the graft was thrombosed, 68 percent (23 of 34) of coronary arteries bypassed were found to have new total occlusions. Segmental contractility was studied in the 153 vascular beds: it was considered improved in 12 percent, unchanged in 49 percent and worse in 39 percent. A possible conclusion from these studies is that
there may be greater progression of occlusive phenomena in the native circulation of those oper· ated upon than might be expected from the natural course of coronary atherosclerotic disease. In addition, there is a clear implication that clinical improvement may be related to bypass patency, infarction of ischemic myocardium, or a combination of both. The answer to the most important question of all,-do these operations improve prognosis for survival?-presently is not available to us. Hopefully, the ongoing prospective randomized study in Veterans Administration hospitals, of operative and nonoperative therapy will eventually provide some answers. Until that time, the careful collection of postoperative data as has been done by the Hopkins group, may provide valuable inferential material in assessing the place of the coronary bypass graft in our therapeutic stockpile. The need to know what this operation does to the heart is as great as the need to demonstrate that it is safe. REFERENCES
2 3
4
.5
Schatz IJ: Commentary on 1971 reflection of 1970 statis· tics. Chest 61 :477, 1972 Report of the Committee on Surgery for Coronary Disease: 1971 reflection of 1970 statistics. Chest 61 :47.5, 1972 Achulf 5, Griffith L, Humphries JO, et al: Myocardial damage after aorto-coronary vein bypass surgery. J Clin Invest .51, la, 1972 Griffith L, Achulf 5, Conti CR, et al: Changes in native coronary circulation and segmental ventricular contractility after saphenous vein coronary bypass graft surgery. Clin Res 20:619, 1972 Humphries JO: Operative procedures for coronary heart disease: An internist's viewpoint. Seminar on Coronary Heart Disease, University of ~Iichigan ~Iedical Ct'Ott'T. Ann Arbor, 11 ~fay 1972
... And the War Goes On Edward B. Diethrich, M.D., F.C.C.P. o
Once again the battle lines are drawn in the seemingly never ending dispute over the role of surgery in the treatment of atherosclerotic heart disease. As history repeats itself, the proponents of the latest operative treatment in the form of aortocoronary bypass grafting are pitted again against those who challenge the new operation as yet °Director, Arizona Heart Instihlte, Phoenix. Reprint requests: Dr. Diethrich, 350 West Thoma.. Road, Phoenix 85013
CHEST, VOL. 63, NO.1, JANUARY, 1973
another in the long list of mostly unproved and disproved surgical therapies dating beyond the days of talcum powder and asbestos. That Effler and colleagues are exhibiting their usual enthusiasm is no surprise to those who have followed this historic confrontation. Spodick and contemporaries reverberate the ageless questions of economics, mortality statistics and hard data in an atmosphere of notorious conservatism. Since the present essays are a reflection of a growing controversy, we must exam-
Sincere and honest physicians can only respond with respect and admiration to this latest information from the Cleveland Clinic. An in-hospital mortality of 1.2 percent for coronary bypass operations is a demonstration of superb care-surely due to an amalgam of efforts from which professional talents, interdisciplinary teamwork and administrative understanding have created an unsurpassed environment for successful open heart operations. Dr. Effier's comments on these data are precisely to the point: those of us involved directly in the care of patients who will undergo bypass procedures would profit by observing and learning what we can from the Cleveland Clinic group. In spite of this, however, should we expect to emulate these results? The answer, as of now, must be a qualified no, for the necessary descriptive information about the Cleveland Clinic cases is just not available to us. Are the patients whom we would consider for bypass operation comparable in a few, most, or all respects with those of Dr. EfHer and his associates? Details of their preoperative clinical status, angiographic characteristics, and hemodynamic parameters are necessary in order for us to conclude that we are dealing with similar groups of patients, and that therefore the goal of achieving an operative mortality rate of 1.2 percent is realistic. As was pointed out,1 if these operations are destined to become more prevalent, then progressively greater use should and must be made of local surgical resources. The need, then, is to know about the operative risks for coronary bypass procedure at the institutions at which most of our patients will be operated upon. Presumably, the bulk of these will be done at local community hospitals and not at highly specialized centers. The data from the Subcommittee for Coronary Disease2 show an overall mortality rate of 7.2-11.8 percent (exclusive of the Cleveland Clinic) in 1970, compiled from those groups responding to the questionnaires of the Committee. These figures are less than breathtaking; obviously they must be taken into account when considering the indications for operations. It is gratifying to learn from Dr. Effier's communication that at a number of community hospitals Professor of Internal ~Iedicine, University of \ledieaJ Center, Ann Arbor.
o Associate
i~an
82
~Iich
throughout the country the hospital mortality for bypass operations approaches that at the Cleveland Clinic. Hopefully, such expertise is contagious, and as a result, a generalized lowering of operative risks for these procedures will be forthcoming. Nevertheless, until such occurs, the practitioner faced with the problem of the patient with symptomatic coronary disease must decide on that therapy which in his opinion is most appropriate in his own local environment. A principal, but not sole, factor in that decision should be a consideration of the risk of dying at the time of, or shortly after the operation. In addition, however, other judgments must enter into this decision. Which patient is to be operated upon, and at what point during the course of the illness? Does the relief of pain after bypass surgery occur in more patients than what one might expect from a placebo, or a sham operation? Does coronary obstructive disease in the bypassed vessel progress more rapidly than it would under other, nonoperative methods of therapy? Does bypass increase or reduce the number and patency of available collaterals? Is it possible (or likely) that these operations relieve pain because they cause infarction? What is the actual incidence of myocardial damage after bypass? What is its significance? Finally, and perhaps most important, do these procedures improve prognosis for survival when properly compared to various forms of nonoperative treatment? In an ideal world, these answers would be available to us before we proposed therapy. Unfortunately, decisions about management often must be made on the basis of incomplete information. There is thus an overpowering need to accumulate objective data documenting the postoperative status of patients, for the assumption that coronary bypass is indicated because it is safe is both dangerous and illogical. Such a conclusion implies that the immediate answer to proximal coronary artery disease is at hand, and that success awaits only the perfection of our coronary angiographic and operative techniques, and the application of meticulous, interdisciplinary intra- and postoperative care. Although this may be the case, there is now insufficient acceptable evidence to support such a contention. Clearly then, it is incumbent upon all who advise and perform these CHEST, VOL. 63, NO.1, JANUARY, 1973
83
AND THE WAR GOES ON
operations to attempt to obtain answers to'some of the above questions. An example of such recently acquired data are the reports from the Johns Hopkins Hospital Group.3.5 Sixty-eight of 153 patients were restudied several months after bypass operation. The preoperative clinical, angiographic and hemodynamic characteristics of those undergoing subsequent investigations were similar to those who were not studied in the postoperative period. Of these 68 patients, 44 had significant localized postoperative electrocardiographic changes consistent with myocardial injury or damage. New and significant Q waves developed in nine; of these, five lost a portion of their native circulation and four showed reduced contractile segmental motion on ventriculography. Of the 20 patients with significant ST segment changes, 18 had either a loss of native circulation, a reduction in segmental motion, or both. Of 15 with evolving T wave changes postoperatively, 12 had reduced segmental motion. Thus, of 44 patients who had electrocardiographic changes, in 37 there was objective evidence suggesting myocardial damage postoperatively. Obstruction of at least a segment of a previously patent coronary artery was found in 46 of 153 of native vascular beds studied. In those vessels in which a bypass graft had not been placed, the incidence of new total occlusion was 23 percent (15 of 66). When the graft was thrombosed, 68 percent (23 of 34) of coronary arteries bypassed were found to have new total occlusions. Segmental contractility was studied in the 153 vascular beds: it was considered improved in 12 percent, unchanged in 49 percent and worse in 39 percent. A possible conclusion from these studies is that
there may be greater progression of occlusive phenomena in the native circulation of those oper· ated upon than might be expected from the natural course of coronary atherosclerotic disease. In addition, there is a clear implication that clinical improvement may be related to bypass patency, infarction of ischemic myocardium, or a combination of both. The answer to the most important question of all,-do these operations improve prognosis for survival?-presently is not available to us. Hopefully, the ongoing prospective randomized study in Veterans Administration hospitals, of operative and nonoperative therapy will eventually provide some answers. Until that time, the careful collection of postoperative data as has been done by the Hopkins group, may provide valuable inferential material in assessing the place of the coronary bypass graft in our therapeutic stockpile. The need to know what this operation does to the heart is as great as the need to demonstrate that it is safe. REFERENCES
2 3
4
.5
Schatz IJ: Commentary on 1971 reflection of 1970 statis· tics. Chest 61 :477, 1972 Report of the Committee on Surgery for Coronary Disease: 1971 reflection of 1970 statistics. Chest 61 :47.5, 1972 Achulf 5, Griffith L, Humphries JO, et al: Myocardial damage after aorto-coronary vein bypass surgery. J Clin Invest .51, la, 1972 Griffith L, Achulf 5, Conti CR, et al: Changes in native coronary circulation and segmental ventricular contractility after saphenous vein coronary bypass graft surgery. Clin Res 20:619, 1972 Humphries JO: Operative procedures for coronary heart disease: An internist's viewpoint. Seminar on Coronary Heart Disease, University of ~Iichigan ~Iedical Ct'Ott'T. Ann Arbor, 11 ~fay 1972
... And the War Goes On Edward B. Diethrich, M.D., F.C.C.P. o
Once again the battle lines are drawn in the seemingly never ending dispute over the role of surgery in the treatment of atherosclerotic heart disease. As history repeats itself, the proponents of the latest operative treatment in the form of aortocoronary bypass grafting are pitted again against those who challenge the new operation as yet °Director, Arizona Heart Instihlte, Phoenix. Reprint requests: Dr. Diethrich, 350 West Thoma.. Road, Phoenix 85013
CHEST, VOL. 63, NO.1, JANUARY, 1973
another in the long list of mostly unproved and disproved surgical therapies dating beyond the days of talcum powder and asbestos. That Effler and colleagues are exhibiting their usual enthusiasm is no surprise to those who have followed this historic confrontation. Spodick and contemporaries reverberate the ageless questions of economics, mortality statistics and hard data in an atmosphere of notorious conservatism. Since the present essays are a reflection of a growing controversy, we must exam-