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Surgical management for acute coronary insufficiency with three years’ follow-up
Surgical management for acute coronary insufficiency with three years' follow-up In this report, acute coronary insufficiency is defined as unstable angina requiring narcotics for relief and an unstable electrocardiogram with or without transient mild enzyme elevations. Forty-five consecutive patients with this syndrome underwent coronary artery grafting with the saphenous vein within 48 hours of the onset of symptoms. They were followed for 3 years. There was an 8.8 per cent operative mortality rate. One long-term survivor sustained a fatal myocardial infarction 18 months postoperatively. One nonfatal myocardial infarction occurred 6 weeks postoperatively. Therefore, the 3 year cumulative mortality rate was 11 per cent and the 3 year myocardial infarction rate was 4 per cent. Thirty-eight patients are in Class I clinical status, 1 is in Class II, and 1 is in Class III.
Graeme L. Hammond, M.D., and Robert A. Poirier, M.D., New Haven, Conn.
Ihe group of patients with coronary artery disease characterized by prolonged rest angina, which is unresponsive to nitrates and associated with transient electrocardiographic changes, represents an interesting problem and one in which the proper course of management is not clear. Certain centers1 have described good results with medical treatment, whereas others2 have described equally good results with surgery. The complex nature of this problem can be appreciated when one tries to name the syndrome: acute coronary insufficiency, intermediate coronary syndrome, unstable angina, or preinfarction angina. At our present level of understanding of the syndrome, there is probably no one correct position that can be uniformily taken as a preferred form of management. In this report, we analyzed all patients with acute coronary insufficiency who were admitted to the Surgical Service of the Yale-New From the Department of Surgery, Yale-New Haven Hospital, Yale Medical School, 333 Cedar Street, New Haven, Conn. 06510. Received for publication Aug. 16, 1974.
Haven Hospital over a 32 month period and reviewed their cumulative 3 year follow-up. However, we did not study a comparable group of medically managed patients. The purpose of this report, therefore, is not to advocate any particular type of management but to review the special problems encountered when surgical management was chosen. Clinical material During the period from June, 1970, to February, 1973, 45 patients were considered to have acute coronary insufficiency by both the cardiologists and surgeons involved in their care. All patients had either sustained or episodic attacks of rest angina, which were unrelieved by nitrates and usually necessitated control by narcotics. Forty patients had electrocardiographic instability characterized by ST-T segment elevations or depressions of greater than 2 mm., with or without T-wave inversions, which occurred during at least one anginal attack. Five patients had electrocardiographic instability characterized by recurrent episodes 625
The Journal of
6 26
Hammond and Poirier
Thoracic and Cardiovascular Surgery
of ventricular tachycardia or fibrillation. This later electrocardiographic instability characteristically began with premature ventricular contractions during the onset of angina. These increased in number as the angina worsened and then developed into the tachyarrhythmias. Eleven patients had mild, transient enzyme elevations without electrocardiographic evidence of transmural infarction. The immediate prcoperative management of these patients consisted of bed rest, sedation, and long-acting nitrates. Nitroglycerin and narcotics were used for relief of acute anginal attacks. Although most patients with a previous history of stable angina were taking propranolol prior to their attack of acute coronary insufficiency, the drug was usually stopped in anticipation of surgery once the patients were admitted to the hospital. Likewise, patients in whom acute coronary insufficiency was their first episode of angina were usually not given propranolol preoperatively. Because this series was concluded before our institution acquired an intra-aortic balloon, this device was not used in pre- or postoperative management. The criteria for considering a patient for urgent coronary reconstruction were an unstable electrocardiogram and severe, unstable rest angina which required narcotics for relief of at least one attack of pain. Electrocardiographic evidence of acute transmural myocardial infarction was considered a contraindication to surgery, but mild transient enzyme elevations were not. These patients underwent coronary arteriography and then were taken to the operating room as soon as possible within the next 48 hours for saphenous vein bypass grafting. No patients who fit the above criteria were refused for surgery, and no patients were refused on the basis of angiographic findings. The average age was 53 years, with a range of 29 to 69 years. All patients were considered to be in New York Heart Association Class IV, as they were bedridden while on medical therapy. No patients were in clinical congestive heart failure, and 28
patients had had one or more previously documented myocardial infarctions. In 10 patients, the current attack of angina was the first manifestation of coronary artery disease, whereas 35 patients had a previous history of angina. At cardiac catheterization, 24 patients had normal ventricles and 21 patients were found to have abnormal ventricles with either one or more areas of akinesis or generalized poor contractions. Ten patients with single vessel disease underwent single aorto-coronary grafting with the saphenous vein. Fifteen patients who had double vessel disease underwent double vein grafting. Twenty patients had triple vessel disease; one of them received a single graft, 10 had double grafts, and 9 patients had triple grafts. Results There were four surgical deaths for an operative mortality rate of 8.8 per cent (Table I ) . One patient, in whom recurrent ventricular fibrillation during anginal attacks had been a major preoperative problem, died 5 hours postoperatively from irreversible ventricular fibrillation. Another patient died 48 hours postoperatively from low cardiac output. This patient developed shock in the catheterization laboratory and, in the operating room, was noted to have sustained a large, hemorrhagic, transmural anterior wall myocardial infarction. A third patient died 10 days postoperatively of a ventricular arrhythmia which was felt to be due to an error in postoperative management. The last patient died 1 month after the operation from acute hemorrhagic pancreatitis. All hospital deaths occurred in the over 60 age group and two of the deaths occurred in the group of 11 patients with enzyme elevations. Postmortem examinations, obtained on 3 patients, revealed that the vein grafts were patent. The cumulative follow-up time was 3 years with a range of 22 to 54 months (Table II). There was one late death which occurred at 18 months. Postmortem examination showed three completely occluded coro-
Volume 69
Acute coronary insufficiency
Number 4
627
April, 1975
nary arteries, an occluded saphenous vein graft to the posterior descending branch of the right coronary, an open graft to the left anterior descending coronary artery, and an acute inferior wall myocardial infarction. The patient had been asymptomatic for a year after the operation. The angina then returned, became progressively worse, and culminated in the fatal myocardial infarction. One of the other survivors sustained a myocardial infarction. This was a transmural anterior wall infarction which occurred 6 weeks following a single vein graft to the left anterior descending coronary artery. The graft was confirmed to be thrombosed at repeat coronary study. The patient survived the infarction and is presently in Class I status 22 months after surgery. In summary, the 3 year cumulative mortality rate was 11 per cent and the 3 year infarction rate was 4 per cent. Of the 40 long-term survivors, 38 are in Class I status according to the New York Heart Association classification, 1 is in Class II, and 1 is in Class III. Preoperatively, the Class III patient had an isolated 90 per cent right coronary lesion with S-T segment elevations which occurred during anginal attacks. Following surgery, the angina persisted, and although the electrocardiogram returned to normal, an exercise test yielded positive results 12 months later. The patient was restudied 4 and 12 months postoperatively, and on both occasions the vein graft was widely patent. The left coronary system was normal, and the lesion in the right coronary artery had not progressed. We have no physiological explanation for the persistent symptoms. This patient presents a distinct variation from our previous experience: That is, patients who remained or again became symptomatic following coronary grafting showed a high correlation with either graft stricture or thrombosis.3 Fourteen patients with twenty-four grafts were studied an average of 11.5 months postoperatively. There were twenty patent grafts and four closed grafts. None were
Table I. Operative deaths
Patient H. A. H. D.
E. D. D. F.
Interval after surgery
Cause of death
5 hours 48 hours 10 days 1 month
Ventricular fibrillation Low cardiac output Arrhythmia Acute hemorrhagic pancreatitis
Table II. Operative deaths and 3 year follow-up of surgically managed patients
I ~No7 Operative deaths Fatal myocardial infarction Free of angina after infarction Free of angina Mild stable angina Severe stable angina Total
4 1 1 37 1 1 45
stenotic. Most of the 31 remaining patients fall into our group of patients who are being studied over 36 months following vein grafting; hence they have not been restudied at the time of this writing. During the same period of time, i.e., from June, 1970, to February, 1973, 2 patients who entered the Surgical Service with acute coronary insufficiency did not undergo surgery. One patient sustained a transmural myocardial infarction 24 hours after catheterization. This individual was followed for 1 year, had stable angina, and refused surgery; the patient has subsequently been lost to follow-up. The second patient sustained a transmural infarction 4 days after catheterization while awaiting surgery. A second, fatal myocardial infarction was sustained 8 months later. Discussion We have observed that the symptoms of many patients with acute coronary insufficiency subside with the intensive medical management which can be provided in a coronary care unit. We have also noted that some of these patients, particularly if symptoms persist, will either sustain a myo-
The Journal of
628
Hammond and Poirier
Thoracic and Cardiovascular Surgery
cardial infarction or die during the hospitalization period. To distinguish which patient will follow which course at which time is a very difficult task. Accordingly, the initial judgments which determine the diagnosis and set the course of medical or surgical management are of considerable importance. Diagnosis. The distinction between stable and unstable angina was usually the first issue to be considered. Stable angina was defined as that which occurred with exercise or stress and tended to be predictable, whereas unstable angina was considered that which occurred at rest, without precipitation, and was different from the patient's previous anginal pattern. The severity of the unstable angina was the factor which initiated surgical consideration. In our experience, the duration of an attack was often not a reliable parameter to assess. This was due to the rapidity by which pharmacologic relief was often rendered in an intensive or coronary care unit. On the other hand, a helpful indication for surgery was the necessity of employing narcotics to relieve one or more of the attacks. Transient electrocardiographic changes which occurred during rest angina were a positive surgical indication; however, the electrocardiographic pattern could be capricious, showing transient changes during one attack but not during another. Accordingly, electrocardiographic criteria for surgical consideration were not believed necessary during all attacks of acute coronary insufficiency. Mild serum enzyme elevations, while present in only 25 per cent of the cases, were also considered a positive surgical indication provided they were not combined with the development of new Q waves. Management. During the period covered by this report, we assumed that a patient with acute coronary insufficiency might sustain a myocardial infarction or die without prompt surgical intervention. This rationale was helpful in terms of adjusting the operating room schedule but, most of the time, probably did little to save lives
or provide prophylaxis for a possible myocardial infarction. In a retrospective study conducted by Solomon,1 an average prodromal period of approximately 1 month was observed before a patient sustained a myocardial infarction. Although Solomon's series and this one are not comparable, Soloman's study illustrates the point that once a patient has developed a change in symptoms, the likelihood of dying suddenly or sustaining a myocardial infarction imminently is not great. This is an important consideration when surgical management is being contemplated. Although transmural myocardial infarction occurred in 2 patients awaiting surgery (24 and 96 hours following cardiac catheterization), there were no deaths in the period between catheterization and operation. On the other hand, of those patients who underwent emergency surgery immediately after cardiac catheterization, 4 died in the hospital. Of course, it is presumptive to assume that these patients would have survived with medical management alone. However, serious problems may be encountered if one always regards these cases as surgical emergencies. For example, the patient who died 48 hours postoperatively of low cardiac output sustained an unrecognized transmural myocardial infarction at some point in transit between the coronary care unit, the cardiac catheterization laboratory, and the operating room. In this case, if surgery had been delayed, serial electrocardiograms might have revealed the transmural infarction. At that time in our institution, such evidence would have ruled out surgery. The patient who died from irreversible ventricular fibrillation 5 hours after emergency surgery had not undergone a trial of arrhythmia stabilization with propranolol, although standard antiarrhythmic therapy had been tried and had failed. Based on the experience gained from this series and our subsequent experience, we believe that these cases usually are not surgical emergencies and that every possible attempt should be made to stabilize the situation with medical management.
Volume 69 Number 4
Acute coronary insufficiency
629
April, 1975
As pointed out by Fischl and colleagues,7 propranolol can be an extremely effective drug for eliminating angina in patients with acute coronary insufficiency. Either by itself or in combination with other antiarrhythmic drugs, propranolol can also be effective in controlling the arrhythmias which sometimes occur with unstable angina. However, we have occasionally encountered difficulty in weaning from bypass those patients who received 160 mg. of propranolol per day or more up to the time of surgery. Therefore, in the period covered by this report, there was a dilemma about the use of propranolol. This dilemma has been largely resolved by use of the intra-aortic balloon. In our more recent experience, if a patient's condition becomes refractory to propranolol in doses exceeding 160 mg. per day during acute medical management, the intra-aortic balloon is inserted and cardiac catheterization performed. If an appropriate surgical situation is found, propranolol is discontinued and the patient is operated upon 48 to 72 hours later. Although the need for surgery in patients whose angina is so severe that it can be controlled only by narcotics or the intraaortic balloon is obvious, the rationale for surgical management becomes more difficult to justify once unstable angina has been brought under good medical control. Indeed, if one bases his decisions on symptoms only, considers each case individually, and recognizes that elective coronary surgery is associated with approximately a 5 per cent operative mortality10-13 and a 15 to 25 per cent closure rate of vein grafts, 9,10 ' 13 ' 14 moderation should be considered, particularly when a single attack of acute coronary insufficiency has come quickly under medical control. Accordingly, an important factor in prospective surgical management may be a previous history of coronary artery disease which has not responded to medical management. The clinical manifestations of coronary artery disease are complex, and the natural history of acute coronary insufficiency with medical management has not been adequately docu-
mented. Consequently, surgical decisions at present are often a matter of group judgment of individual cases based on severity of symptoms, effectiveness of medical management, and stability of the electrocardiogram. The variations in definition and management of the syndrome from center to center and, until recently,2-7' s the lack of confirmation by coronary arteriography make statistics comparing surgically managed patients from one institution with medically managed patients from another meaningless. Despite the inconsistencies of data, however, a common thread which runs through many reports 57 on acute coronary insufficiency is that this diagnosis carries with it a more ominous prognosis than that for stable angina.15,1G If surgical management is contemplated, these data indicate that it is more hazardous to operate during the acute stage and that usually little will be lost by stabilizing the patient's condition and then performing elective coronary surgery in 2 days to 2 weeks. During 1973, the operative mortality rate at Yale for elective coronary surgery in 200 consecutive patients with angina was 4.5 per cent. This is approximately half that for the emergency surgery reported in this series. However, the long-term results indicate that good palliation from angina can be achieved. Although conclusions on survival cannot be drawn at this time, the results seem encouraging. Addendum Since returning galley proof, we have learned that 1 patient died 4 years, 7 months following surgery. Postmortem examination was not obtained, but clinical information indicates that the patient died from cardiac causes. REFERENCES 1 Krauss, K. R., Hutter, A. M„ Jr., and DeSanctis, R. W.: Acute Coronary Insufficiency: Course and Follow-up, Circulation 45: 66, 1972 (Suppl. I). 2 Miller, C , Cannom, D., Fogarty, T„ Schroeder, J., Daily, P., and Harrison, D.: Saphenous Vein Coronary Artery Bypass in Patients With "Preinfarction Angina," Circulation 47: 234, 1973.
The Journal of
630
Hammond and Poirier
Thoracic and Cardiovascular Surgery
3 Hammond, G. L., and Poirier, R. A.: Early and Late Results of Direct Coronary Reconstructuve Surgery for Angina, J. THORAC. CARDIOVASC. SURG. 65:
127,
1973.
4 Solomon, H. A., Edwards, A. L., and Killip, T.: Prodromata in Acute Myocardial Infarction, Circulation 40: 463, 1969. 5 Mounsey, P.: Prodromal Symptoms in Myocardial Infarction, Br. Heart J. 13: 215, 1951. 6 Vakil, R. J.: Preinfarction Syndrome: Management and Follow-up, Am. J. Cardiol. 14: 55, 1964. 7 Fischl, S. J., Herman, M. V., and Gorlin, R.: The Intermediate Coronary Syndrome: Clinical, Angiographic and Therapeutic Aspects, N. Engl. J. Med. 288: 1193, 1973. 8 Conti, C. R., Brawley, R. K., Griffith, L. S. C , et al.: Unstable Angina Pectoris: Morbidity and Mortality in 57 Consecutive Patients evaluated Angiographically, Am. J. Cardiol. 32: 745, 1973. 9 Hammond, G. L., and Poirier, R. A.: Graft Patency and Changes in Coronary Lesions and Left Ventricular Function Following Saphenous Vein Grafting, Circulation 48: 173, 1973. 10 Alderman, E. L., Matlof, H. J., Wexler, L., et al.: Results of Direct Coronary-Artery Sur-
gery for the Treatment of Angina Pectoris, N. Engl. J. Med. 288: 535, 1973. 11 Cannom, D. S., Miller, D. C , Shumway, N. E., et al.: The Long Term Follow-up of Patients Undergoing Saphenous Vein Bypass Surgery, Circulation 49: 77, 1974. 12 Cooley, D. A., Dawson, J. T., Hallman, G. L., et al.: Aortocoronary Saphenous Vein Bypass: Results in 1,492 Patients With Particular Reference to Patients With Complicating Features, Ann. Thorac. Surg. 16: 380, 1973. 13 Effler, D. B., Favaloro, R. G., and Groves, L. K.: Coronary Artery Surgery Utilizing Saphenous Vein Graft Techniques: Clinical Experience With 224 Operations, J. THORAC. CARDIOVASC. SURG. 59:
147,
1971.
14 Anderson, R. P., Bonchek, L. I., Wood, J. A., et al.: The Safety of Combined Aortic Valve Replacement and Coronary Bypass Grafting, Ann. Thorac. Surg. 15: 249, 1973. 15 Kannel, W. B., and Feinleib, M.: Natural History of Angina Pectoris in the Framingham Study: Prognosis and Survival, Am. J. Cardiol. 29: 154, 1972. 16 Frank, C. W., Weinblatt, E., and Shapiro, S.: Angina Pectoris in Men: Prognostic Significance of Selected Medical Factors, Circulation 47: 509, 1973.
Graeme L. Hammond, M.D., and Robert A. Poirier, M.D., New Haven, Conn.
Ihe group of patients with coronary artery disease characterized by prolonged rest angina, which is unresponsive to nitrates and associated with transient electrocardiographic changes, represents an interesting problem and one in which the proper course of management is not clear. Certain centers1 have described good results with medical treatment, whereas others2 have described equally good results with surgery. The complex nature of this problem can be appreciated when one tries to name the syndrome: acute coronary insufficiency, intermediate coronary syndrome, unstable angina, or preinfarction angina. At our present level of understanding of the syndrome, there is probably no one correct position that can be uniformily taken as a preferred form of management. In this report, we analyzed all patients with acute coronary insufficiency who were admitted to the Surgical Service of the Yale-New From the Department of Surgery, Yale-New Haven Hospital, Yale Medical School, 333 Cedar Street, New Haven, Conn. 06510. Received for publication Aug. 16, 1974.
Haven Hospital over a 32 month period and reviewed their cumulative 3 year follow-up. However, we did not study a comparable group of medically managed patients. The purpose of this report, therefore, is not to advocate any particular type of management but to review the special problems encountered when surgical management was chosen. Clinical material During the period from June, 1970, to February, 1973, 45 patients were considered to have acute coronary insufficiency by both the cardiologists and surgeons involved in their care. All patients had either sustained or episodic attacks of rest angina, which were unrelieved by nitrates and usually necessitated control by narcotics. Forty patients had electrocardiographic instability characterized by ST-T segment elevations or depressions of greater than 2 mm., with or without T-wave inversions, which occurred during at least one anginal attack. Five patients had electrocardiographic instability characterized by recurrent episodes 625
The Journal of
6 26
Hammond and Poirier
Thoracic and Cardiovascular Surgery
of ventricular tachycardia or fibrillation. This later electrocardiographic instability characteristically began with premature ventricular contractions during the onset of angina. These increased in number as the angina worsened and then developed into the tachyarrhythmias. Eleven patients had mild, transient enzyme elevations without electrocardiographic evidence of transmural infarction. The immediate prcoperative management of these patients consisted of bed rest, sedation, and long-acting nitrates. Nitroglycerin and narcotics were used for relief of acute anginal attacks. Although most patients with a previous history of stable angina were taking propranolol prior to their attack of acute coronary insufficiency, the drug was usually stopped in anticipation of surgery once the patients were admitted to the hospital. Likewise, patients in whom acute coronary insufficiency was their first episode of angina were usually not given propranolol preoperatively. Because this series was concluded before our institution acquired an intra-aortic balloon, this device was not used in pre- or postoperative management. The criteria for considering a patient for urgent coronary reconstruction were an unstable electrocardiogram and severe, unstable rest angina which required narcotics for relief of at least one attack of pain. Electrocardiographic evidence of acute transmural myocardial infarction was considered a contraindication to surgery, but mild transient enzyme elevations were not. These patients underwent coronary arteriography and then were taken to the operating room as soon as possible within the next 48 hours for saphenous vein bypass grafting. No patients who fit the above criteria were refused for surgery, and no patients were refused on the basis of angiographic findings. The average age was 53 years, with a range of 29 to 69 years. All patients were considered to be in New York Heart Association Class IV, as they were bedridden while on medical therapy. No patients were in clinical congestive heart failure, and 28
patients had had one or more previously documented myocardial infarctions. In 10 patients, the current attack of angina was the first manifestation of coronary artery disease, whereas 35 patients had a previous history of angina. At cardiac catheterization, 24 patients had normal ventricles and 21 patients were found to have abnormal ventricles with either one or more areas of akinesis or generalized poor contractions. Ten patients with single vessel disease underwent single aorto-coronary grafting with the saphenous vein. Fifteen patients who had double vessel disease underwent double vein grafting. Twenty patients had triple vessel disease; one of them received a single graft, 10 had double grafts, and 9 patients had triple grafts. Results There were four surgical deaths for an operative mortality rate of 8.8 per cent (Table I ) . One patient, in whom recurrent ventricular fibrillation during anginal attacks had been a major preoperative problem, died 5 hours postoperatively from irreversible ventricular fibrillation. Another patient died 48 hours postoperatively from low cardiac output. This patient developed shock in the catheterization laboratory and, in the operating room, was noted to have sustained a large, hemorrhagic, transmural anterior wall myocardial infarction. A third patient died 10 days postoperatively of a ventricular arrhythmia which was felt to be due to an error in postoperative management. The last patient died 1 month after the operation from acute hemorrhagic pancreatitis. All hospital deaths occurred in the over 60 age group and two of the deaths occurred in the group of 11 patients with enzyme elevations. Postmortem examinations, obtained on 3 patients, revealed that the vein grafts were patent. The cumulative follow-up time was 3 years with a range of 22 to 54 months (Table II). There was one late death which occurred at 18 months. Postmortem examination showed three completely occluded coro-
Volume 69
Acute coronary insufficiency
Number 4
627
April, 1975
nary arteries, an occluded saphenous vein graft to the posterior descending branch of the right coronary, an open graft to the left anterior descending coronary artery, and an acute inferior wall myocardial infarction. The patient had been asymptomatic for a year after the operation. The angina then returned, became progressively worse, and culminated in the fatal myocardial infarction. One of the other survivors sustained a myocardial infarction. This was a transmural anterior wall infarction which occurred 6 weeks following a single vein graft to the left anterior descending coronary artery. The graft was confirmed to be thrombosed at repeat coronary study. The patient survived the infarction and is presently in Class I status 22 months after surgery. In summary, the 3 year cumulative mortality rate was 11 per cent and the 3 year infarction rate was 4 per cent. Of the 40 long-term survivors, 38 are in Class I status according to the New York Heart Association classification, 1 is in Class II, and 1 is in Class III. Preoperatively, the Class III patient had an isolated 90 per cent right coronary lesion with S-T segment elevations which occurred during anginal attacks. Following surgery, the angina persisted, and although the electrocardiogram returned to normal, an exercise test yielded positive results 12 months later. The patient was restudied 4 and 12 months postoperatively, and on both occasions the vein graft was widely patent. The left coronary system was normal, and the lesion in the right coronary artery had not progressed. We have no physiological explanation for the persistent symptoms. This patient presents a distinct variation from our previous experience: That is, patients who remained or again became symptomatic following coronary grafting showed a high correlation with either graft stricture or thrombosis.3 Fourteen patients with twenty-four grafts were studied an average of 11.5 months postoperatively. There were twenty patent grafts and four closed grafts. None were
Table I. Operative deaths
Patient H. A. H. D.
E. D. D. F.
Interval after surgery
Cause of death
5 hours 48 hours 10 days 1 month
Ventricular fibrillation Low cardiac output Arrhythmia Acute hemorrhagic pancreatitis
Table II. Operative deaths and 3 year follow-up of surgically managed patients
I ~No7 Operative deaths Fatal myocardial infarction Free of angina after infarction Free of angina Mild stable angina Severe stable angina Total
4 1 1 37 1 1 45
stenotic. Most of the 31 remaining patients fall into our group of patients who are being studied over 36 months following vein grafting; hence they have not been restudied at the time of this writing. During the same period of time, i.e., from June, 1970, to February, 1973, 2 patients who entered the Surgical Service with acute coronary insufficiency did not undergo surgery. One patient sustained a transmural myocardial infarction 24 hours after catheterization. This individual was followed for 1 year, had stable angina, and refused surgery; the patient has subsequently been lost to follow-up. The second patient sustained a transmural infarction 4 days after catheterization while awaiting surgery. A second, fatal myocardial infarction was sustained 8 months later. Discussion We have observed that the symptoms of many patients with acute coronary insufficiency subside with the intensive medical management which can be provided in a coronary care unit. We have also noted that some of these patients, particularly if symptoms persist, will either sustain a myo-
The Journal of
628
Hammond and Poirier
Thoracic and Cardiovascular Surgery
cardial infarction or die during the hospitalization period. To distinguish which patient will follow which course at which time is a very difficult task. Accordingly, the initial judgments which determine the diagnosis and set the course of medical or surgical management are of considerable importance. Diagnosis. The distinction between stable and unstable angina was usually the first issue to be considered. Stable angina was defined as that which occurred with exercise or stress and tended to be predictable, whereas unstable angina was considered that which occurred at rest, without precipitation, and was different from the patient's previous anginal pattern. The severity of the unstable angina was the factor which initiated surgical consideration. In our experience, the duration of an attack was often not a reliable parameter to assess. This was due to the rapidity by which pharmacologic relief was often rendered in an intensive or coronary care unit. On the other hand, a helpful indication for surgery was the necessity of employing narcotics to relieve one or more of the attacks. Transient electrocardiographic changes which occurred during rest angina were a positive surgical indication; however, the electrocardiographic pattern could be capricious, showing transient changes during one attack but not during another. Accordingly, electrocardiographic criteria for surgical consideration were not believed necessary during all attacks of acute coronary insufficiency. Mild serum enzyme elevations, while present in only 25 per cent of the cases, were also considered a positive surgical indication provided they were not combined with the development of new Q waves. Management. During the period covered by this report, we assumed that a patient with acute coronary insufficiency might sustain a myocardial infarction or die without prompt surgical intervention. This rationale was helpful in terms of adjusting the operating room schedule but, most of the time, probably did little to save lives
or provide prophylaxis for a possible myocardial infarction. In a retrospective study conducted by Solomon,1 an average prodromal period of approximately 1 month was observed before a patient sustained a myocardial infarction. Although Solomon's series and this one are not comparable, Soloman's study illustrates the point that once a patient has developed a change in symptoms, the likelihood of dying suddenly or sustaining a myocardial infarction imminently is not great. This is an important consideration when surgical management is being contemplated. Although transmural myocardial infarction occurred in 2 patients awaiting surgery (24 and 96 hours following cardiac catheterization), there were no deaths in the period between catheterization and operation. On the other hand, of those patients who underwent emergency surgery immediately after cardiac catheterization, 4 died in the hospital. Of course, it is presumptive to assume that these patients would have survived with medical management alone. However, serious problems may be encountered if one always regards these cases as surgical emergencies. For example, the patient who died 48 hours postoperatively of low cardiac output sustained an unrecognized transmural myocardial infarction at some point in transit between the coronary care unit, the cardiac catheterization laboratory, and the operating room. In this case, if surgery had been delayed, serial electrocardiograms might have revealed the transmural infarction. At that time in our institution, such evidence would have ruled out surgery. The patient who died from irreversible ventricular fibrillation 5 hours after emergency surgery had not undergone a trial of arrhythmia stabilization with propranolol, although standard antiarrhythmic therapy had been tried and had failed. Based on the experience gained from this series and our subsequent experience, we believe that these cases usually are not surgical emergencies and that every possible attempt should be made to stabilize the situation with medical management.
Volume 69 Number 4
Acute coronary insufficiency
629
April, 1975
As pointed out by Fischl and colleagues,7 propranolol can be an extremely effective drug for eliminating angina in patients with acute coronary insufficiency. Either by itself or in combination with other antiarrhythmic drugs, propranolol can also be effective in controlling the arrhythmias which sometimes occur with unstable angina. However, we have occasionally encountered difficulty in weaning from bypass those patients who received 160 mg. of propranolol per day or more up to the time of surgery. Therefore, in the period covered by this report, there was a dilemma about the use of propranolol. This dilemma has been largely resolved by use of the intra-aortic balloon. In our more recent experience, if a patient's condition becomes refractory to propranolol in doses exceeding 160 mg. per day during acute medical management, the intra-aortic balloon is inserted and cardiac catheterization performed. If an appropriate surgical situation is found, propranolol is discontinued and the patient is operated upon 48 to 72 hours later. Although the need for surgery in patients whose angina is so severe that it can be controlled only by narcotics or the intraaortic balloon is obvious, the rationale for surgical management becomes more difficult to justify once unstable angina has been brought under good medical control. Indeed, if one bases his decisions on symptoms only, considers each case individually, and recognizes that elective coronary surgery is associated with approximately a 5 per cent operative mortality10-13 and a 15 to 25 per cent closure rate of vein grafts, 9,10 ' 13 ' 14 moderation should be considered, particularly when a single attack of acute coronary insufficiency has come quickly under medical control. Accordingly, an important factor in prospective surgical management may be a previous history of coronary artery disease which has not responded to medical management. The clinical manifestations of coronary artery disease are complex, and the natural history of acute coronary insufficiency with medical management has not been adequately docu-
mented. Consequently, surgical decisions at present are often a matter of group judgment of individual cases based on severity of symptoms, effectiveness of medical management, and stability of the electrocardiogram. The variations in definition and management of the syndrome from center to center and, until recently,2-7' s the lack of confirmation by coronary arteriography make statistics comparing surgically managed patients from one institution with medically managed patients from another meaningless. Despite the inconsistencies of data, however, a common thread which runs through many reports 57 on acute coronary insufficiency is that this diagnosis carries with it a more ominous prognosis than that for stable angina.15,1G If surgical management is contemplated, these data indicate that it is more hazardous to operate during the acute stage and that usually little will be lost by stabilizing the patient's condition and then performing elective coronary surgery in 2 days to 2 weeks. During 1973, the operative mortality rate at Yale for elective coronary surgery in 200 consecutive patients with angina was 4.5 per cent. This is approximately half that for the emergency surgery reported in this series. However, the long-term results indicate that good palliation from angina can be achieved. Although conclusions on survival cannot be drawn at this time, the results seem encouraging. Addendum Since returning galley proof, we have learned that 1 patient died 4 years, 7 months following surgery. Postmortem examination was not obtained, but clinical information indicates that the patient died from cardiac causes. REFERENCES 1 Krauss, K. R., Hutter, A. M„ Jr., and DeSanctis, R. W.: Acute Coronary Insufficiency: Course and Follow-up, Circulation 45: 66, 1972 (Suppl. I). 2 Miller, C , Cannom, D., Fogarty, T„ Schroeder, J., Daily, P., and Harrison, D.: Saphenous Vein Coronary Artery Bypass in Patients With "Preinfarction Angina," Circulation 47: 234, 1973.
The Journal of
630
Hammond and Poirier
Thoracic and Cardiovascular Surgery
3 Hammond, G. L., and Poirier, R. A.: Early and Late Results of Direct Coronary Reconstructuve Surgery for Angina, J. THORAC. CARDIOVASC. SURG. 65:
127,
1973.
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