- Email: [email protected]
Preinfarction angina pectoris
Preinfarction angina pectoris A surgical emergency Robert R. Goodin, M.D. (by invitation), Thomas V. Inglesby, M.D. (by invitation), Allan M. Lansing, M.D. (by invitation), and Myron W. Wheat, Jr., M.D., Louisville, Ky.
The clinical spectrum of coronary atherosclerosis is an extremely broad one, from the asymptomatic lesions found in young Vietnam!" and Korean war victims to overt myocardial infarction, cardiogenic shock, and death. In 1961, Wood'" noted that about 10 per cent of patients presenting with coronary atherosclerotic heart disease could be clinically identified as having a pre infarction angina syndrome. This syndrome was first mentioned by Cobb Parry in 1799 and again by Herrick in 1912. Eliaser first attempted to define the syndrome in clinical terms in 1937. Spencer-" has recently defined preinfarction angina as a degree of coronary insufficiency intermediate in severity between chronic angina pectoris on the one hand and overt myocardial infarction on the other hand. The syndrome has been known by many terms over the years," including more recently preinfarction angina pectoris,": 29 unstable angina pectoris," crescendo angina pectoris, impending myocardial infarction.": 30 and coronary insufficiency." As could be expected, the definitions of this syndrome have also varied widely. In many recent publications, the criteria used to define the synFrom the Departments of Medicine and Surgery, University of Louisville School of Medicine, Louisville, Ky. 40201. Read at the Fifty-third Annual Meeting of The American Association for Thoracic Surgery, Dallas, Texas, April 16, 17, and 18, 1973.
934
drome have not been stated." The recent developments of aorto-coronary bypass graft by saphenous vein and internal mammary artery techniques have shown promise of significant increase in distal coronary flow in patients with proximal obstructive coronary artery disease. To date, however, the indications for bypass surgery have not been clearly determined. Theoretically, the bypass graft operation should be found most applicable in those patients who are most disabled by angina pectoris and who are most likely to progress rapidly to overt myocardial infarction. In this report we review our experience with patients presenting with preinfarction angina pectoris. A plea is made for better definition of the syndrome, and criteria for defining the syndrome are suggested. It is hoped that this report will help to select the proper therapy for patients with preinfarction angina pectoris. Materials and methods During the period November, 1971, to September, 1972, a total of 19 patients with preinfarction angina pectoris were studied by cardiac catheterization and coronary arteriography at the University of Louisville School of Medicine. During this same period, a total of 166 patients were studied because of suspected coronary atherosclerotic heart disease. The diagnosis of preinfarction angina pectoris was made
Volume 66 Number 6 December, 1973
prior to catheterization studies and only if all of the following criteria were met: (l) prolonged angina pectoris (more than 20 minutes), (2) pain occurring at rest, (3) pain not relieved by nitroglycerin, (4) pain recurrent despite in-hospital therapy, (5) electrocardiographic changes present but limited to ST and T changes, and (6) no evidence of myocardial infarction by QRS changes or serum enzyme changes (serum glutamic oxaloacetic transaminase [SGOT], creatine phosphokinase [CPK], and lactate dehydrogenase [LDH]). We have excluded cases in which overt infarction was suspected by clinical presentation, even if not confirmed by electrocardiography or enzyme changes. We have also excluded those patients with chronic severe angina, recent onset angina, and nocturnal or rest angina unless all the stated criteria were met. All patients had been hospitalized for varying periods of time when consultation was requested. All patients who met the above criteria and were subjected to cardiac catheterization during this period are included. Patients who were not considered potential candidates for saphenous vein bypass surgery because of severe left ventricular failure or associated disease were excluded. Careful clinical evaluation by history and physical examination was carried out on all patients by one of us prior to catheterization studies. Serial electrocardiograms and serum enzyme (SGOT, CPK, and LDH) studies were done prior to catheterization to exclude acute myocardial infarction. Left heart catheterization, single-plane left ventriculography, and coronary cineangiography were performed in the fasted state with no premedication. The Sones brachial arteriotomy technique was used in all cases. Pressures were recorded on the Electronics for Medicine DR-12 recorder and cineangiograms were recorded on 35 mm. Kodak double X film, with General Electric Fluoricon 300 radiographic equipment. During this period of time all patients with preinfarction angina were considered candidates for aorto-coronary bypass graft
Preinfarction angina pectoris
935
surgery if it was found technically feasible after catheterization studies. Those patients with associated valvular heart disease and/or left ventricular aneurysm were excluded. Postoperative catheterization studies were requested at 6 to 12 months. Followup information was obtained on all patients, including those who were operated upon and those who were not. Results
During the 10 month period of this study, 19 patients with preinfarction angina pectoris were studied. These patients represent 11.3 per cent of all patients studied because of suspected coronary atherosclerosis and 5.8 per cent of all patients undergoing cardiac catheterization in our laboratory. Twelve of the 19 patients underwent aortocoronary bypass surgery with the saphenous vein, while 7 patients were treated medically for various reasons (outlined below). The two patient groups were remarkably similar from a clinical standpoint. By definition, all patients had recurrent, prolonged pain with ischemic electrocardiographic changes but without evidence of myocardial infarction. The average age of the patients who were operated upon was 53.2 years, while those not operated upon averaged 52.7 years. Fifty per cent of the surgically treated patients had previous myocardial infarction, whereas 57 per cent of the medically treated patients had previous myocardial infarction. The duration of symptoms was similar in the two groups. From a clinical standpoint, severity and duration of pain, frequency of pain, electrocardiographic changes, and clinical presentation, the two patient groups could not be differentiated (Table I). However, patients who were operated upon had fewer abnormalities at catheterization (Table II). Only 5 of the 12 operated patients had elevated resting left ventricular end-diastolic pressure (> 12 mm. Hg), while 6 of 7 unoperated patients had abnormal end-diastolic pressures. The average number of vessels with greater than 50 per cent occlusion was 2.17 per patient in operated patients and 2.85
The Journal of
936
Goodin et at.
Thoracic and Cardiovascular Surgery
Table I. Presentation of preinfarction angina UnopOperated erated patients patients
Chronic angina pectoris with abrupt change Previous M.1. with pain-free interval Recent onset angina pectoris « 4 mo.)
7
4
4
2
Legend: M.l., Myocardial infarction.
Table II. Catheterization findings in 19 patients with preinfarction angina pectoris
Patient
No. vessels with>
LVEDP
LV contractile
50% occlu-
(mm. Hg)
Abn. (0-4+)
sion
Operated patients
M. S. J. A. P. B. C. M. D. S. L. W.
F.B.
T. S. M. P. L. M. W. U. K. G.
7 11 10
7 12 26 28 7 19 4 17 20
3+ 0 2+ 0 0 2+ 3+ 1+ 3+ 1+ 3+ 2+
2 2 2 I
2 2 2 3 2 3 2 3
Unoperated patients
G. S. R. H. E. T. H. C. J. R. W. H. A. W.
18 28 17 14 13
36 11
1+ 3+ 0 2+ 1+ 4+ 0
3 3 3 2 3 3 3
to surgical intervention. Sixteen of the 19 patients studied (84.2 per cent) were found to be candidates for operation by hemodynamic and angiographic results. Results of operation (Table III) Twelve patients were subjected to aortocoronary bypass with the saphenous vein. Six patients received single grafts and 6 received double grafts. The average interval from onset of the preinfarction state to surgery was 5.6 weeks (range 1 to 12 weeks). There was one operative death (from bleeding), resulting in an operative mortality rate of 8.3 per cent. Postoperative complications consisted of acute myocardial infarction in 1 patient and transient congestive heart failure in a second patient. The average duration of hospitalization after operation was 11.5 days. The 11 survivors of surgery have been followed an average of 10.5 months (range 8 to 13 months). Five of these patients are asymptomatic and carry out normal activities while the remaining patients continue to have mild limitation of activity due to angina pectoris. None of the 11 surviving patients have suffered myocardial infarction or congestive heart failure since hospital discharge. Postoperative catheterization studies have been performed in 5 patients with a total of seven grafts from 3 to 10 months after surgery. There were six patent grafts in 7 patients, for an over-all graft patency rate of 85.7 per cent. In only I patient were all grafts occluded.
Legend: LVEDP, Left ventricular end-diastolic pressure. LV, Left ventricular. Abn., Abnormality.
Unoperated patients (Table IV)
in unoperated patients. A similar number of operated patients (67 per cent) and unoperated patients (71 per cent) were found to have abnormal contractions by left ventricular cineangiography. No patients meeting our criteria for preinfarction angina pectoris were found to have normal arteries on coronary arteriography. Three patients in the operated group were noted to have serious ventricular arrhythmias (ventricular tachycardia or ventricular fibrillation) prior
Seven patients were not subjected to revascularization surgery. Three of these patients were considered unsuitable candidates for operation either because of severe left ventricular dysfunction or because the distribution of lesions made surgery by saphenous vein bypass graft impossible. Of these 3 patients, 1 died suddenly 6 weeks after the onset of preinfarction angina and 2 remain severely disabled by angina pectoris. Of the remaining 4 patients not opperated, 2 patients died of myocardial in-
Volume 66
Preinjarction angina pectoris
Number 6
937
December, 1973
Table III. Patients with preiniarction angina pectoris who were operated upon Patient
Age
Prior M.l.
M. S.
57 47 47 61 55 54 59 61 54 58 43 43
Yes No Yes No No No No Yes Yes Yes Yes No
J. A. P. B.
C. M. D. S. L. W. F. B.
T. S. M. P. L. M. W. U. K. G.
Onset to surgery (wk.)
Postop. interval (mo.)
12
Postop. results
Asymptomatic Asymptomatic Asymptomatic Class II angina Class III angina Class II angina Class II angina Asymptomatic Class II angina
13
12 10 11 14
1Yz
5 8 5
7 6 2 6 4 5 6
10
10 9 8 Died*
10 8
Asymptomatic Class II angina
'The patient died on the second postoperative day.
farction 2 and 3 weeks after the onset of symptoms while awaiting surgery. The other 2 patients have survived acute myocardial infarctions 4 weeks and 5 weeks after the onset, also while awaiting surgery. Of the total 7 patients not operated, 3 have died an average of 3.7 weeks (2 to 6 weeks) after the onset of preinfarction angina, 2 have suffered nonfatal myocardial infarctions, and 2 remain severely disabled by angina pectoris 8 and 12 months later. No complications were encountered during cardiac catheterization and coronary cineangiography in these patients. Discussion
Preinfarction angina pectoris is the third most common clinical presentation of coronary atherosclerotic heart disease. This syndrome occurs second only to chronic angina pectoris and overt myocardial infarction and just ahead of subendocardial infarction." Wood-" noted that 10 per cent of all patients with coronary atherosclerotic heart disease presented with a preinfarction syndrome. Krauss and colleagues" have reported that 19 per cent of patients admitted to their coronary care unit had no evidence of overt infarction and should be considered to have had preinfarction angina pectoris. Lopes and associates" have reported similar findings. Many authors have noted the high incidence of significant preinfarction symptoms in patients who are admitted with overt myo-
Table IV. Patients with preinjarction angina pectoris who were not operated upon FollowPrior up interM.l. val (wk.)
Patient
Age (yr.)
G.S. R.H.
53 51
Yes Yes
41h
E.T. H.C.
63 43
Yes Yes
6 5
J. R.
58
No
17
W.H.
47
No
8
A.W.
54
No
2
3
Result
Sudden death Nonfatal acute M.1. Sudden death Nonfatal acute M.1. Class IV angina pectoris Class IV angina pectoris Fatal acute M.1.
cardial infarction.l": "", "C, In 1969 Solomon's group"H reported that 65 per cent of a consecutive series of patients admitted with acute myocardial infarction had significant prodromata prior to the development of overt infarction. In the great majority of patients, the prodromal symptom was progressive angina pectoris, present for I to 3 weeks in most of them. These findings suggest that a large number of patients suffer preinfarction angina pectoris and should be clinically identifiable. From the large number of terms used in this syndrome, it is apparent that a single, well-defined term has not yet been accepted. As early as 1961, Wood'" suggested that the syndrome represents a clinically
The Journal of
938
Goodin et al.
Thoracic and Cardiovascular Surgery
Table V. Prognosis in preinjarction angina Mortality rate (%)
Authors
Vakils. 3 Wood 2 2 Beamish and Storrie> 18 months Resnik! 1 month Krauss et aI.20 12 months Sustaita et aVo month Goodin et aI. 3 months
35 30 30 3 35
20 0 15
87
46
71
43
identifiable syndrome. Since all patients with this set of findings do not progress to overt myocardial infarction, the term preinfarction angina pectoris is technically incorrect. Vakil" suggests that the term preinfarction angina is a good one since it alerts the doctor to the probable course of events and also impresses on the patient the importance of immediate inhospital care. Fowler" has recently emphasized the urgent need for a better definition of the syndrome regardless of what we call it. It is apparent from review of the literature that different criteria are used to define the syndrome. We would agree with Fowler" that until we establish criteria for definition of the syndrome, we will remain unable to determine the natural history of the disease and to assess the results of therapy. Many series of patients with preinfarction angina are reported with no listing of criteria used to define the syndrome. Despite the fact that this syndrome is basically defined by clinical criteria which are in part subjective, we feel that it can be clearly defined and suggest the following criteria: (I) prolonged angina pectoris (more than 20 minutes), (2) pain occurring at rest, (3) pain not relieved by nitroglycerin, (4) pain recurrent despite in-hospital therapy, (5) electrocardiographic changes present but limited to ST and T changes, and (6) no evidence of myocardial infarction by QRS changes or serum enzyme changes (SGOT, CPK, and LDH). We suggest that all the stated criteria
must be met to make a diagnosis of preinfarction angina and that those cases of severe angina in which all the criteria are not met be labeled unstable angina. It is suspected from our early results in unoperated patients that strict adherence to these criteria will define a critically ill group of patients at high risk of progression to overt myocardial infarction and death. The requirement of ischemic electrocardiographic changes adds an objective criterion and should reduce the number of patients misdiagnosed as having preinfarction angina who are later found to have normal coronary arteries. It is probable that patients suffering serious ventricular arrhythmias such as ventricular tachycardia or fibrillation as well as those with Prinzmetal angina" should be considered to have preinfarction angina pectoris even if all the stated criteria are not met, since these patients are at high risk of overt myocardial infarction and death. In the literature many authors have stressed the high incidence of progression to overt infarction and death in patients with preinfarction angina--": c , 20. "2, "C,."" (Table V). However, a wide range of prognosis is reported among these authors. Krauss:" reported an 85 per cent I year survival rate in such patients, while others have reported a I year survival rate as low as 50 per cent. Similarly, the incidence of progression to overt myocardial infarction is reported as low as 15 per cent and as high as 92 per cent within 3 months of onset.v " In our small series of unoperated patients, the incidence of overt infarction was 71 per cent within 3 months of onset, and 43 per cent were dead within 3 months of onset. The rather poor prognosis found in our patients is likely related to the rigid criteria required for inclusion in the preinfarction angina group. The proper management of patients with preinfarction angina has not been determined. Wood." Vakil," and others! have suggested that anticoagulants can dramatically reduce the incidence of progression to overt myocardial infarction and death.
Volume 66 Number 6
Preinjarction angina pectoris
939
December, 1973
However, more recent reports:" have failed to show significant benefit of anticoagulant therapy. The lack of knowledge regarding pathophysiology in such cases has made selection of proper therapy difficult. The pathophysiology may be thrombosis, subintimal hemorrhage, progressive atherosclerosis, or possibly vasospasm. The electrocardiogram and serum enzyme studies do not clearly differentiate between reversible cellular damage and irreversible cell necrosis. 1 The important point would appear to be that patients meeting the suggested criteria for preinfarction angina pectoris are at great risk of progression to overt myocardial infarction and death. Over the past 5 to 6 years, aorto-coronary bypass grafting with the saphenous vein has become widely accepted as a means of increasing distal coronary flow in patients with proximal occlusive disease. This operation, done as an elective procedure, has resulted in clinical improvement in 80 per cent of patients at a low operative risk.'? Cineangiographic coronary artery studies'< " as well as pathologic studies' have shown that the distribution of coronary atherosclerotic lesions is such that a high percentage of patients can be considered candidates for this operation, In our series, 84 per cent of patients studied were found to have lesions that could be bypassed, from a technical standpoint. The bypass operation has been shown beneficial in the relief of angina pectoris, but its value in preventing myocardial infarction and prolonging life has not yet been demonstrated. The clinical indications for aorto-coronary bypass with the saphenous vein have not yet been defined. Theoretically, the patient with preinfarction angina should be an excellent candidate for this operation. In such patients the operation should provide immediate relief of pain and prevent progression to myocardial infarction and death. A large number of reports in the past 2 years have demonstrated the feasibility of this operation in patients with syndromes'<- 14-1G, 21. 2:1, 28, 29 preinfarction (Table VI). These reports indicate an aver-
Table VI. Saphenous vein graft for preinfarction angina
Author
Auer et al.21 Favaloro et al,12, 13 Pifarre et al.l :; Lambert et aU" Pittman:'?
Linhart et al.4 Hill et al."Bolooki et al." Conti et al.2 8 Sustaita et aU" Goodin et al. Totals
No. of patients
M.I. with Operative survivors mortality of surgery (%) rate (%)
41
0
18 12 57 39 5 3 3 40 36 12 266
11 8 5.3 10 0 0 0 22.5 8.3 8.3 8.3
0 6.2 0 4 0 0 0 0 0 9.1 8.3 2.8
age operative mortality rate of 8.3 per cent and an average incidence of myocardial infarction among survivors of 2.8 per cent. Our findings were similar to those of others. Many years of follow-up and data obtained regarding graft patency and left ventricular function will be required to determine the ultimate course of operated patients compared with such patients treated medically. The methods of patient selection for surgery obviously affect the outcome, since those patients with severe left ventricular dysfunction and anatomically inoperable lesions cannot be considered comparable to patients being treated surgically and can be expected to have a worse prognosis. A carefully controlled study comparing surgical and medical management of patients with preinfarction angina will be required to answer this question but seems unlikely to be performed. It appears that once catheterization and surgery are decided upon, they should be carried out without delay. In this series, 4 patients suffered fatal or nonfatal myocardial infarctions while awaiting surgery, I day to 4 weeks after catheterization. Our current policy in patients with preinfarction angina pectoris is as follows: Once our criteria for this diagnosis are met, we advise immediate left heart catheterization and coronary angiography. If the patient is
940
The Journal of Thoracic and Cardiovascular Surgery
Goodin et al.
found hemodynamically and anatomically suitable for aorto-coronary bypass, surgery is carried out without delay. The patient presenting with Prinzmetal or variant angina pectoris deserves further mention. Silverman? has recently emphasized the poor prognosis of such patients when treated medically. Pathologically, these patients are usually found to have severe proximal lesions and are therefore ideal candidates for bypass surgery.": 11 One of our patients (J. A.) with Prinzmetal angina and multiple episodes of ventricular fibrillation had an uneventful postoperative course and remains asymptomatic II months after surgery. It would appear that patients with Prinzmetal angina are best managed surgically. Summary
Nineteen patients with preinfarction angina pectoris were studied over a 10 month period. Twelve of these patients were subjected to aorto-coronary bypass surgery with the saphenous vein. There was one operative death, but good clinical results were obtained in the survivors followed 8 to 13 months postoperatively. Seven patients were not operated upon; 3 have died and 2 have sustained nonfatal myocardial infarctions during the first 3 months of follow-up. The urgent need for a universally accepted set of criteria to define the preinfarction angina pectoris syndrome is discussed, and a set of criteria is suggested. This study suggests that patients with preinfarction angina as defined by our criteria are best managed surgically and that continued use of bypass surgery in such patients is justified. Addendum
Since the completion of this study (Sept. 1, 1972), an additional 22 patients meeting the stated criteria for preinfarction angina pectoris have been studied at catheterization. Eighteen of these patients have had one or more saphenous vein aorto-coronary bypass grafts with three operative deaths. Of the 15 survivors of surgery, 9 have had complete relief of pain, 5 are considered in
cardiac Class II, and 1 remains significantly disabled by angina pectoris, 1 to 5 months after surgery. Four patients were not operated upon: 2 refused surgery and 2 were considered inoperable. Of these 4 patients, 1 died suddenly 6 weeks after study, 2 remain significantly disabled by angina pectoris, and 1 has shown clinical improvement. Our current totals then represent 30 operated patients with an operative mortality rate of 13.3 per cent and 11 unoperated patients with six myocardial infarctions (54.5 per cent) and four deaths (36.3 per cent). REFERENCES
2
3 4
5
6
7
8
9 IO
11
12
13
Resnik, W.: The Significance of Prolonged Anginal Pain, Am. Heart J. 63: 290, 1962. Vakil, R.: Preinfarction Syndrome: Management and Follow-up, Am. J. Cardio\. 14: 55, 1964. Vakil, R.: Intermediate Coronary Syndrome, Circulation 24: 557, 1961. Linhart, J., Beller, B., and Talley, R.: Preinfarction Angina. Clinical, Hemodynamic and Angiographic Evaluation, Chest 61: 312, 1972. Bolooki, H., Vargas, A., Ghahramani, A., et al.: Aortocoronary Bypass Graft for Preinfarction Angina, Chest 61: 247, 1972. Fowler, N.: "Preinfarctional" Angina: A Need for an Objective Definition and for a Controlled Clinical Trial of Its Management, Circulation 44: 755, 1971. Glassman, E., Spencer, F., Tice, D., Weisinger, B., and Green, G.: What Percentage of Patients With Angina Pectoris Are Candidates for Bypass Grafts? Circulation 43: 101, 1971 (Supp\. I). Berger, R., and Story, H.: Assessment of Operability by the Saphenous Vein Bypass Operation, N. Eng\. J. Med. 285: 248, 1971. Silverman, M.: Variant Angina Pectoris, Ann. Intern. Med. 75: 339, 1971. Lown, B., Whiting, R. B., Klein, M. D., Vander Veer, 1., and Lown, B.: Prinzmetal or Variant Angina Pectoris, N. Eng\. J. Med. 282: 709, 1970. Guazzi, M., Polese, A., Fiorentini, C.; et al.: Prinzmetal Angina: Left Ventricular Function During Attacks, Br. Heart J. 33: 84, 1971. Favaloro, R. G., and Cheanvechai, c.: Myocardial Revascularization by the Saphenous Vein Graft, Geriatrics 27: 80, 1972. Favaloro, R. G., Effler, D. B., Cheanvechai, C., Quint, R., and Sones, M.: Acute Coronary Insufficiency (Impending Myocardial Infarc-
Volume 66 Number 6 December, 1973
tion and Myocardial Infarction), Am. J. Cardiol. 28: 598, 1971. 14 Hill, J., Kerth, W., Kelly, J., Selzer, A., Armstrong, W., Popper, R., Langston, M., and Cohn, K.: Emergency Aortocoronary Bypass for Impending or Extending Myocardial Infarction, Circulation 43: 105, 1971 (Suppl, I). 15 Pifarre, R., Spinazzola, A, Nernickas, R., et al.: Emergency Aortocoronary Bypass for Acute Myocardial Infarction, Arch. Surg. 103: 525, 1971. 16 Spencer, F.: Bypass Grafting for Preinfarction Angina, Circulation 45: 1314, 1972. 17 Friedberg, c.: Caution and Coronary Artery Surgery, Circulation 45: 727, 1972. 18 Glenn, W.: Some Reflections on Coronary Bypass Surgery, Circulation 45: 869, 1972. 19 McNamara, 1. J., Molot, M. A, Stremple, J. F., et al.: Coronary Artery Disease in Combat Casualties in Vietnam, J. A M. A 216: 1185, 1971. 20 Krauss, K., Hutter, A. M., Jr., and DeSanctis, R. W.: Acute Coronary Insufficiency: Clinical Course and Follow-up (Abstr.), Circulation 44: 102, 1971 (Suppl. II). 21 Auer, J., Johnson, D., Flernrna, R., Tector, A, and Lepley, D.: Direct Coronary Artery Surgery for Impending Myocardial Infarction (Abstr.), Circulation 44: 102, 1971 (Supp!. 11). 22 Wood, P.: Acute and S, bacute Coronary Insufficiency, Br. Med. J. I: 1779, 1961. 23 Lambert, c., Adam, M., Geisler, G. F., Verzosa, E., Nazarian, M., and Mitchel, B. F., Jr.: Emergency Myocardial Revascularization for Impending Infarctions and Arrhythmias, J. THORAc. CARDIOVASC. SURG. 62: 522, 1971. 24 Proudfitt, W., Shirey, E., and Sones, M.: Distribution of Arterial Lesions Demonstrated by Selective Cinecoronary Arteriography, Circulation 36: 54, 1967. 25 Beamish, R., and Storrie, V.: Impending Myocardial Infarction, Circulation 21: 1107, 1960. 26 Solomon, H., Edwards, A, and Killip, T.: Prodromata in Acute Myocardial Infarction, Circulation 40: 463, 1969. 27 Lopes, M., Spivack, A., Harrison, D., and Schroeder, J.: Prognosis of Noninfarction Coronary Care Unit Patients (Abstr.), Am. J. Cardiol, 31: 144, 1973. 28 Conti, R., Bramley, R., Pitt, B., and Ross, R.: Unstable Angina: Morbidity and Mortality in 57 Consecutive Patients Evaluated Angiographically (Abstr.), Am. J. Cardio!. 31: 127, 1973. 29 Sustaita, H., Chatterjee, K., Matioff, J., and Swan, H.: The Rationale for Surgery in Preinfarction Angina (Abstr.), Am. J. Cardiol, 31: 160, 1973. 30 Segal, B., Likoff, W., Brock, H., Kimberes, D., Najma, M., and Linhart, J.: Saphenous Vein
Preinfarction angina pectoris
94 1
Bypass Surgery for Impending Myocardial Infarction, J. A M. A 223: 767, 1973. 31 Pittman, D.: American College of Cardiology Presentation, Washington, D. c., February, 1973.
Discussion DR. JOHN E. HUTCHINSON New York. N. Y.
I congratulate the authors for emphasizing the point that some patients with preinfarction anginal syndromes are true surgical emergencies. We have had several patients in whom prompt surgical intervention has undoubtedly salvaged myocardial tissue that was destined for necrosis. In some patients, we have considered urgent or immediate operation as analogous to operations for acute emboli to the femoral artery. There is a golden time interval before transmural infarction occurs and muscle necrosis becomes irreversible. I would like to describe one patient whom we treated. A 44-year-old man was admitted to our coronary care unit with severe substernal chest pain, an unstable electrocardiogram, and normal serum enzyme determinations. Emergency coronary arteriography was performed. There was some aneurysmal dilatation of the upper one third of the right coronary artery, but no major obstructions. On injection of the left main coronary artery, we found an extremely severe stenosis of the proximal anterior descending coronary artery with a normal appearing circumflex system. The contractility of the anterior left ventricle was markedly impaired. An emergency operation was performed 2 hours after the study. Striking improvement in left ventricular contractility was noted on the operating table immediately after institution of flow through a vein bypass to the anterior descending coronary artery. A repeat angiocardiogram, performed 15 days after operation, showed that the vein graft to the middle third of the anterior descending coronary artery was patent. When the left main coronary artery was injected, there was no filling of the distal anterior descending. After the operation, there was marked improvement in left ventricular contractility in the distribution of the anterior descending coronary artery. Dramatic cases like this one certainly confirm the opinion that some patients with preinfarction angina are true surgical emergencies and should be operated upon in the next hour or so, rather than the next day, 2 days, or the next week. DR. WILLIAM B. FORD Pittsburgh, Pa.
I congratulate Dr. Goodin and the co-authors for their work. We also are aware of the opinion
The Journal af
942
Goodin et al.
that this clinical entity is a surgical emergency. Without coronary cine studies, of course, surgical intervention is not justified. In general, these patients are not in immediate danger of death, but they may be in immediate danger of myocardial infarction. Once a diagnosis is made, we believe that 6,000 units of heparin should be given intravenously at once and continued every 4 hours. Then, the cine studies and other diagnostic studies can be done. Several years ago Drs. Beamish, Vakil, and Nichols used heparin in patients who had the preinfarction syndrome, comparing the results with those obtained in a control group. They found that morbidity and mortality rates decreased in the patients who were given heparin. Of course, we do not believe that heparin is good for long-term therapy of coronary arterial occlusive disease. We have treated 14 patients with intravenous heparin before operation and then have performed the grafting procedures. All patients were operated upon within 72 hours after the clinical diagnosis was made. There were no deaths. Thirteen patients were relieved of their angina. The fourteenth patient developed severe precordial pain on the tenth postoperative day. The cine study showed that both grafts were patent, and I week later the pain regressed. We did not understand the cause of her pain. We believe that the use of heparin will change the preinfarction syndrome patient from a surgi-
Thoracic and Cardiovascular Surgery
cal emergency to one of urgency. Therefore, we can avoid the rush and the tension of a procedure that should be done immediately. DR. GOODIN (Closing) I would like to thank Drs. Hutchinson and Ford for their comments. We have not routinely used anticoagulants in the medical therapy of pre infarction angina. When we anticipate surgical intervention, we try to avoid Inderal therapy. Many people including ourselves feel that Inderal is an excellent drug in the management of angina pectoris. We usually institute Inderal therapy on admission in patients with severe angina pectoris. However, we prefer not to operate upon patients who have been on Inderal in the previous 48 to 72 hours, and this can create a dilemma. Basically, if pain persists and we make a diagnosis of preinfarction angina, we recommend surgery and discontinue Inderal therapy. In regard to preoperative abnormalities disclosed by left ventriculography, it would appear that if we are dealing with a true preinfarction state and the patient has not had prior myocardial infarctions, we should reasonably expect the hypokinesis and akinesis to disappear after revascularization of the involved segments. Thus, in the preinfarction angina patient, hypokinesis and akinesis do not necessarily preclude the possibility of effective revascularization surgery.
Introductory abstracts
Beginning in January, 1974, it is requested that each article begin with a brief abstract. Authors submitting articles on or after September 1, 1973, should supply an abstract of 150 words or less.
The clinical spectrum of coronary atherosclerosis is an extremely broad one, from the asymptomatic lesions found in young Vietnam!" and Korean war victims to overt myocardial infarction, cardiogenic shock, and death. In 1961, Wood'" noted that about 10 per cent of patients presenting with coronary atherosclerotic heart disease could be clinically identified as having a pre infarction angina syndrome. This syndrome was first mentioned by Cobb Parry in 1799 and again by Herrick in 1912. Eliaser first attempted to define the syndrome in clinical terms in 1937. Spencer-" has recently defined preinfarction angina as a degree of coronary insufficiency intermediate in severity between chronic angina pectoris on the one hand and overt myocardial infarction on the other hand. The syndrome has been known by many terms over the years," including more recently preinfarction angina pectoris,": 29 unstable angina pectoris," crescendo angina pectoris, impending myocardial infarction.": 30 and coronary insufficiency." As could be expected, the definitions of this syndrome have also varied widely. In many recent publications, the criteria used to define the synFrom the Departments of Medicine and Surgery, University of Louisville School of Medicine, Louisville, Ky. 40201. Read at the Fifty-third Annual Meeting of The American Association for Thoracic Surgery, Dallas, Texas, April 16, 17, and 18, 1973.
934
drome have not been stated." The recent developments of aorto-coronary bypass graft by saphenous vein and internal mammary artery techniques have shown promise of significant increase in distal coronary flow in patients with proximal obstructive coronary artery disease. To date, however, the indications for bypass surgery have not been clearly determined. Theoretically, the bypass graft operation should be found most applicable in those patients who are most disabled by angina pectoris and who are most likely to progress rapidly to overt myocardial infarction. In this report we review our experience with patients presenting with preinfarction angina pectoris. A plea is made for better definition of the syndrome, and criteria for defining the syndrome are suggested. It is hoped that this report will help to select the proper therapy for patients with preinfarction angina pectoris. Materials and methods During the period November, 1971, to September, 1972, a total of 19 patients with preinfarction angina pectoris were studied by cardiac catheterization and coronary arteriography at the University of Louisville School of Medicine. During this same period, a total of 166 patients were studied because of suspected coronary atherosclerotic heart disease. The diagnosis of preinfarction angina pectoris was made
Volume 66 Number 6 December, 1973
prior to catheterization studies and only if all of the following criteria were met: (l) prolonged angina pectoris (more than 20 minutes), (2) pain occurring at rest, (3) pain not relieved by nitroglycerin, (4) pain recurrent despite in-hospital therapy, (5) electrocardiographic changes present but limited to ST and T changes, and (6) no evidence of myocardial infarction by QRS changes or serum enzyme changes (serum glutamic oxaloacetic transaminase [SGOT], creatine phosphokinase [CPK], and lactate dehydrogenase [LDH]). We have excluded cases in which overt infarction was suspected by clinical presentation, even if not confirmed by electrocardiography or enzyme changes. We have also excluded those patients with chronic severe angina, recent onset angina, and nocturnal or rest angina unless all the stated criteria were met. All patients had been hospitalized for varying periods of time when consultation was requested. All patients who met the above criteria and were subjected to cardiac catheterization during this period are included. Patients who were not considered potential candidates for saphenous vein bypass surgery because of severe left ventricular failure or associated disease were excluded. Careful clinical evaluation by history and physical examination was carried out on all patients by one of us prior to catheterization studies. Serial electrocardiograms and serum enzyme (SGOT, CPK, and LDH) studies were done prior to catheterization to exclude acute myocardial infarction. Left heart catheterization, single-plane left ventriculography, and coronary cineangiography were performed in the fasted state with no premedication. The Sones brachial arteriotomy technique was used in all cases. Pressures were recorded on the Electronics for Medicine DR-12 recorder and cineangiograms were recorded on 35 mm. Kodak double X film, with General Electric Fluoricon 300 radiographic equipment. During this period of time all patients with preinfarction angina were considered candidates for aorto-coronary bypass graft
Preinfarction angina pectoris
935
surgery if it was found technically feasible after catheterization studies. Those patients with associated valvular heart disease and/or left ventricular aneurysm were excluded. Postoperative catheterization studies were requested at 6 to 12 months. Followup information was obtained on all patients, including those who were operated upon and those who were not. Results
During the 10 month period of this study, 19 patients with preinfarction angina pectoris were studied. These patients represent 11.3 per cent of all patients studied because of suspected coronary atherosclerosis and 5.8 per cent of all patients undergoing cardiac catheterization in our laboratory. Twelve of the 19 patients underwent aortocoronary bypass surgery with the saphenous vein, while 7 patients were treated medically for various reasons (outlined below). The two patient groups were remarkably similar from a clinical standpoint. By definition, all patients had recurrent, prolonged pain with ischemic electrocardiographic changes but without evidence of myocardial infarction. The average age of the patients who were operated upon was 53.2 years, while those not operated upon averaged 52.7 years. Fifty per cent of the surgically treated patients had previous myocardial infarction, whereas 57 per cent of the medically treated patients had previous myocardial infarction. The duration of symptoms was similar in the two groups. From a clinical standpoint, severity and duration of pain, frequency of pain, electrocardiographic changes, and clinical presentation, the two patient groups could not be differentiated (Table I). However, patients who were operated upon had fewer abnormalities at catheterization (Table II). Only 5 of the 12 operated patients had elevated resting left ventricular end-diastolic pressure (> 12 mm. Hg), while 6 of 7 unoperated patients had abnormal end-diastolic pressures. The average number of vessels with greater than 50 per cent occlusion was 2.17 per patient in operated patients and 2.85
The Journal of
936
Goodin et at.
Thoracic and Cardiovascular Surgery
Table I. Presentation of preinfarction angina UnopOperated erated patients patients
Chronic angina pectoris with abrupt change Previous M.1. with pain-free interval Recent onset angina pectoris « 4 mo.)
7
4
4
2
Legend: M.l., Myocardial infarction.
Table II. Catheterization findings in 19 patients with preinfarction angina pectoris
Patient
No. vessels with>
LVEDP
LV contractile
50% occlu-
(mm. Hg)
Abn. (0-4+)
sion
Operated patients
M. S. J. A. P. B. C. M. D. S. L. W.
F.B.
T. S. M. P. L. M. W. U. K. G.
7 11 10
7 12 26 28 7 19 4 17 20
3+ 0 2+ 0 0 2+ 3+ 1+ 3+ 1+ 3+ 2+
2 2 2 I
2 2 2 3 2 3 2 3
Unoperated patients
G. S. R. H. E. T. H. C. J. R. W. H. A. W.
18 28 17 14 13
36 11
1+ 3+ 0 2+ 1+ 4+ 0
3 3 3 2 3 3 3
to surgical intervention. Sixteen of the 19 patients studied (84.2 per cent) were found to be candidates for operation by hemodynamic and angiographic results. Results of operation (Table III) Twelve patients were subjected to aortocoronary bypass with the saphenous vein. Six patients received single grafts and 6 received double grafts. The average interval from onset of the preinfarction state to surgery was 5.6 weeks (range 1 to 12 weeks). There was one operative death (from bleeding), resulting in an operative mortality rate of 8.3 per cent. Postoperative complications consisted of acute myocardial infarction in 1 patient and transient congestive heart failure in a second patient. The average duration of hospitalization after operation was 11.5 days. The 11 survivors of surgery have been followed an average of 10.5 months (range 8 to 13 months). Five of these patients are asymptomatic and carry out normal activities while the remaining patients continue to have mild limitation of activity due to angina pectoris. None of the 11 surviving patients have suffered myocardial infarction or congestive heart failure since hospital discharge. Postoperative catheterization studies have been performed in 5 patients with a total of seven grafts from 3 to 10 months after surgery. There were six patent grafts in 7 patients, for an over-all graft patency rate of 85.7 per cent. In only I patient were all grafts occluded.
Legend: LVEDP, Left ventricular end-diastolic pressure. LV, Left ventricular. Abn., Abnormality.
Unoperated patients (Table IV)
in unoperated patients. A similar number of operated patients (67 per cent) and unoperated patients (71 per cent) were found to have abnormal contractions by left ventricular cineangiography. No patients meeting our criteria for preinfarction angina pectoris were found to have normal arteries on coronary arteriography. Three patients in the operated group were noted to have serious ventricular arrhythmias (ventricular tachycardia or ventricular fibrillation) prior
Seven patients were not subjected to revascularization surgery. Three of these patients were considered unsuitable candidates for operation either because of severe left ventricular dysfunction or because the distribution of lesions made surgery by saphenous vein bypass graft impossible. Of these 3 patients, 1 died suddenly 6 weeks after the onset of preinfarction angina and 2 remain severely disabled by angina pectoris. Of the remaining 4 patients not opperated, 2 patients died of myocardial in-
Volume 66
Preinjarction angina pectoris
Number 6
937
December, 1973
Table III. Patients with preiniarction angina pectoris who were operated upon Patient
Age
Prior M.l.
M. S.
57 47 47 61 55 54 59 61 54 58 43 43
Yes No Yes No No No No Yes Yes Yes Yes No
J. A. P. B.
C. M. D. S. L. W. F. B.
T. S. M. P. L. M. W. U. K. G.
Onset to surgery (wk.)
Postop. interval (mo.)
12
Postop. results
Asymptomatic Asymptomatic Asymptomatic Class II angina Class III angina Class II angina Class II angina Asymptomatic Class II angina
13
12 10 11 14
1Yz
5 8 5
7 6 2 6 4 5 6
10
10 9 8 Died*
10 8
Asymptomatic Class II angina
'The patient died on the second postoperative day.
farction 2 and 3 weeks after the onset of symptoms while awaiting surgery. The other 2 patients have survived acute myocardial infarctions 4 weeks and 5 weeks after the onset, also while awaiting surgery. Of the total 7 patients not operated, 3 have died an average of 3.7 weeks (2 to 6 weeks) after the onset of preinfarction angina, 2 have suffered nonfatal myocardial infarctions, and 2 remain severely disabled by angina pectoris 8 and 12 months later. No complications were encountered during cardiac catheterization and coronary cineangiography in these patients. Discussion
Preinfarction angina pectoris is the third most common clinical presentation of coronary atherosclerotic heart disease. This syndrome occurs second only to chronic angina pectoris and overt myocardial infarction and just ahead of subendocardial infarction." Wood-" noted that 10 per cent of all patients with coronary atherosclerotic heart disease presented with a preinfarction syndrome. Krauss and colleagues" have reported that 19 per cent of patients admitted to their coronary care unit had no evidence of overt infarction and should be considered to have had preinfarction angina pectoris. Lopes and associates" have reported similar findings. Many authors have noted the high incidence of significant preinfarction symptoms in patients who are admitted with overt myo-
Table IV. Patients with preinjarction angina pectoris who were not operated upon FollowPrior up interM.l. val (wk.)
Patient
Age (yr.)
G.S. R.H.
53 51
Yes Yes
41h
E.T. H.C.
63 43
Yes Yes
6 5
J. R.
58
No
17
W.H.
47
No
8
A.W.
54
No
2
3
Result
Sudden death Nonfatal acute M.1. Sudden death Nonfatal acute M.1. Class IV angina pectoris Class IV angina pectoris Fatal acute M.1.
cardial infarction.l": "", "C, In 1969 Solomon's group"H reported that 65 per cent of a consecutive series of patients admitted with acute myocardial infarction had significant prodromata prior to the development of overt infarction. In the great majority of patients, the prodromal symptom was progressive angina pectoris, present for I to 3 weeks in most of them. These findings suggest that a large number of patients suffer preinfarction angina pectoris and should be clinically identifiable. From the large number of terms used in this syndrome, it is apparent that a single, well-defined term has not yet been accepted. As early as 1961, Wood'" suggested that the syndrome represents a clinically
The Journal of
938
Goodin et al.
Thoracic and Cardiovascular Surgery
Table V. Prognosis in preinjarction angina Mortality rate (%)
Authors
Vakils. 3 Wood 2 2 Beamish and Storrie> 18 months Resnik! 1 month Krauss et aI.20 12 months Sustaita et aVo month Goodin et aI. 3 months
35 30 30 3 35
20 0 15
87
46
71
43
identifiable syndrome. Since all patients with this set of findings do not progress to overt myocardial infarction, the term preinfarction angina pectoris is technically incorrect. Vakil" suggests that the term preinfarction angina is a good one since it alerts the doctor to the probable course of events and also impresses on the patient the importance of immediate inhospital care. Fowler" has recently emphasized the urgent need for a better definition of the syndrome regardless of what we call it. It is apparent from review of the literature that different criteria are used to define the syndrome. We would agree with Fowler" that until we establish criteria for definition of the syndrome, we will remain unable to determine the natural history of the disease and to assess the results of therapy. Many series of patients with preinfarction angina are reported with no listing of criteria used to define the syndrome. Despite the fact that this syndrome is basically defined by clinical criteria which are in part subjective, we feel that it can be clearly defined and suggest the following criteria: (I) prolonged angina pectoris (more than 20 minutes), (2) pain occurring at rest, (3) pain not relieved by nitroglycerin, (4) pain recurrent despite in-hospital therapy, (5) electrocardiographic changes present but limited to ST and T changes, and (6) no evidence of myocardial infarction by QRS changes or serum enzyme changes (SGOT, CPK, and LDH). We suggest that all the stated criteria
must be met to make a diagnosis of preinfarction angina and that those cases of severe angina in which all the criteria are not met be labeled unstable angina. It is suspected from our early results in unoperated patients that strict adherence to these criteria will define a critically ill group of patients at high risk of progression to overt myocardial infarction and death. The requirement of ischemic electrocardiographic changes adds an objective criterion and should reduce the number of patients misdiagnosed as having preinfarction angina who are later found to have normal coronary arteries. It is probable that patients suffering serious ventricular arrhythmias such as ventricular tachycardia or fibrillation as well as those with Prinzmetal angina" should be considered to have preinfarction angina pectoris even if all the stated criteria are not met, since these patients are at high risk of overt myocardial infarction and death. In the literature many authors have stressed the high incidence of progression to overt infarction and death in patients with preinfarction angina--": c , 20. "2, "C,."" (Table V). However, a wide range of prognosis is reported among these authors. Krauss:" reported an 85 per cent I year survival rate in such patients, while others have reported a I year survival rate as low as 50 per cent. Similarly, the incidence of progression to overt myocardial infarction is reported as low as 15 per cent and as high as 92 per cent within 3 months of onset.v " In our small series of unoperated patients, the incidence of overt infarction was 71 per cent within 3 months of onset, and 43 per cent were dead within 3 months of onset. The rather poor prognosis found in our patients is likely related to the rigid criteria required for inclusion in the preinfarction angina group. The proper management of patients with preinfarction angina has not been determined. Wood." Vakil," and others! have suggested that anticoagulants can dramatically reduce the incidence of progression to overt myocardial infarction and death.
Volume 66 Number 6
Preinjarction angina pectoris
939
December, 1973
However, more recent reports:" have failed to show significant benefit of anticoagulant therapy. The lack of knowledge regarding pathophysiology in such cases has made selection of proper therapy difficult. The pathophysiology may be thrombosis, subintimal hemorrhage, progressive atherosclerosis, or possibly vasospasm. The electrocardiogram and serum enzyme studies do not clearly differentiate between reversible cellular damage and irreversible cell necrosis. 1 The important point would appear to be that patients meeting the suggested criteria for preinfarction angina pectoris are at great risk of progression to overt myocardial infarction and death. Over the past 5 to 6 years, aorto-coronary bypass grafting with the saphenous vein has become widely accepted as a means of increasing distal coronary flow in patients with proximal occlusive disease. This operation, done as an elective procedure, has resulted in clinical improvement in 80 per cent of patients at a low operative risk.'? Cineangiographic coronary artery studies'< " as well as pathologic studies' have shown that the distribution of coronary atherosclerotic lesions is such that a high percentage of patients can be considered candidates for this operation, In our series, 84 per cent of patients studied were found to have lesions that could be bypassed, from a technical standpoint. The bypass operation has been shown beneficial in the relief of angina pectoris, but its value in preventing myocardial infarction and prolonging life has not yet been demonstrated. The clinical indications for aorto-coronary bypass with the saphenous vein have not yet been defined. Theoretically, the patient with preinfarction angina should be an excellent candidate for this operation. In such patients the operation should provide immediate relief of pain and prevent progression to myocardial infarction and death. A large number of reports in the past 2 years have demonstrated the feasibility of this operation in patients with syndromes'<- 14-1G, 21. 2:1, 28, 29 preinfarction (Table VI). These reports indicate an aver-
Table VI. Saphenous vein graft for preinfarction angina
Author
Auer et al.21 Favaloro et al,12, 13 Pifarre et al.l :; Lambert et aU" Pittman:'?
Linhart et al.4 Hill et al."Bolooki et al." Conti et al.2 8 Sustaita et aU" Goodin et al. Totals
No. of patients
M.I. with Operative survivors mortality of surgery (%) rate (%)
41
0
18 12 57 39 5 3 3 40 36 12 266
11 8 5.3 10 0 0 0 22.5 8.3 8.3 8.3
0 6.2 0 4 0 0 0 0 0 9.1 8.3 2.8
age operative mortality rate of 8.3 per cent and an average incidence of myocardial infarction among survivors of 2.8 per cent. Our findings were similar to those of others. Many years of follow-up and data obtained regarding graft patency and left ventricular function will be required to determine the ultimate course of operated patients compared with such patients treated medically. The methods of patient selection for surgery obviously affect the outcome, since those patients with severe left ventricular dysfunction and anatomically inoperable lesions cannot be considered comparable to patients being treated surgically and can be expected to have a worse prognosis. A carefully controlled study comparing surgical and medical management of patients with preinfarction angina will be required to answer this question but seems unlikely to be performed. It appears that once catheterization and surgery are decided upon, they should be carried out without delay. In this series, 4 patients suffered fatal or nonfatal myocardial infarctions while awaiting surgery, I day to 4 weeks after catheterization. Our current policy in patients with preinfarction angina pectoris is as follows: Once our criteria for this diagnosis are met, we advise immediate left heart catheterization and coronary angiography. If the patient is
940
The Journal of Thoracic and Cardiovascular Surgery
Goodin et al.
found hemodynamically and anatomically suitable for aorto-coronary bypass, surgery is carried out without delay. The patient presenting with Prinzmetal or variant angina pectoris deserves further mention. Silverman? has recently emphasized the poor prognosis of such patients when treated medically. Pathologically, these patients are usually found to have severe proximal lesions and are therefore ideal candidates for bypass surgery.": 11 One of our patients (J. A.) with Prinzmetal angina and multiple episodes of ventricular fibrillation had an uneventful postoperative course and remains asymptomatic II months after surgery. It would appear that patients with Prinzmetal angina are best managed surgically. Summary
Nineteen patients with preinfarction angina pectoris were studied over a 10 month period. Twelve of these patients were subjected to aorto-coronary bypass surgery with the saphenous vein. There was one operative death, but good clinical results were obtained in the survivors followed 8 to 13 months postoperatively. Seven patients were not operated upon; 3 have died and 2 have sustained nonfatal myocardial infarctions during the first 3 months of follow-up. The urgent need for a universally accepted set of criteria to define the preinfarction angina pectoris syndrome is discussed, and a set of criteria is suggested. This study suggests that patients with preinfarction angina as defined by our criteria are best managed surgically and that continued use of bypass surgery in such patients is justified. Addendum
Since the completion of this study (Sept. 1, 1972), an additional 22 patients meeting the stated criteria for preinfarction angina pectoris have been studied at catheterization. Eighteen of these patients have had one or more saphenous vein aorto-coronary bypass grafts with three operative deaths. Of the 15 survivors of surgery, 9 have had complete relief of pain, 5 are considered in
cardiac Class II, and 1 remains significantly disabled by angina pectoris, 1 to 5 months after surgery. Four patients were not operated upon: 2 refused surgery and 2 were considered inoperable. Of these 4 patients, 1 died suddenly 6 weeks after study, 2 remain significantly disabled by angina pectoris, and 1 has shown clinical improvement. Our current totals then represent 30 operated patients with an operative mortality rate of 13.3 per cent and 11 unoperated patients with six myocardial infarctions (54.5 per cent) and four deaths (36.3 per cent). REFERENCES
2
3 4
5
6
7
8
9 IO
11
12
13
Resnik, W.: The Significance of Prolonged Anginal Pain, Am. Heart J. 63: 290, 1962. Vakil, R.: Preinfarction Syndrome: Management and Follow-up, Am. J. Cardio\. 14: 55, 1964. Vakil, R.: Intermediate Coronary Syndrome, Circulation 24: 557, 1961. Linhart, J., Beller, B., and Talley, R.: Preinfarction Angina. Clinical, Hemodynamic and Angiographic Evaluation, Chest 61: 312, 1972. Bolooki, H., Vargas, A., Ghahramani, A., et al.: Aortocoronary Bypass Graft for Preinfarction Angina, Chest 61: 247, 1972. Fowler, N.: "Preinfarctional" Angina: A Need for an Objective Definition and for a Controlled Clinical Trial of Its Management, Circulation 44: 755, 1971. Glassman, E., Spencer, F., Tice, D., Weisinger, B., and Green, G.: What Percentage of Patients With Angina Pectoris Are Candidates for Bypass Grafts? Circulation 43: 101, 1971 (Supp\. I). Berger, R., and Story, H.: Assessment of Operability by the Saphenous Vein Bypass Operation, N. Eng\. J. Med. 285: 248, 1971. Silverman, M.: Variant Angina Pectoris, Ann. Intern. Med. 75: 339, 1971. Lown, B., Whiting, R. B., Klein, M. D., Vander Veer, 1., and Lown, B.: Prinzmetal or Variant Angina Pectoris, N. Eng\. J. Med. 282: 709, 1970. Guazzi, M., Polese, A., Fiorentini, C.; et al.: Prinzmetal Angina: Left Ventricular Function During Attacks, Br. Heart J. 33: 84, 1971. Favaloro, R. G., and Cheanvechai, c.: Myocardial Revascularization by the Saphenous Vein Graft, Geriatrics 27: 80, 1972. Favaloro, R. G., Effler, D. B., Cheanvechai, C., Quint, R., and Sones, M.: Acute Coronary Insufficiency (Impending Myocardial Infarc-
Volume 66 Number 6 December, 1973
tion and Myocardial Infarction), Am. J. Cardiol. 28: 598, 1971. 14 Hill, J., Kerth, W., Kelly, J., Selzer, A., Armstrong, W., Popper, R., Langston, M., and Cohn, K.: Emergency Aortocoronary Bypass for Impending or Extending Myocardial Infarction, Circulation 43: 105, 1971 (Suppl, I). 15 Pifarre, R., Spinazzola, A, Nernickas, R., et al.: Emergency Aortocoronary Bypass for Acute Myocardial Infarction, Arch. Surg. 103: 525, 1971. 16 Spencer, F.: Bypass Grafting for Preinfarction Angina, Circulation 45: 1314, 1972. 17 Friedberg, c.: Caution and Coronary Artery Surgery, Circulation 45: 727, 1972. 18 Glenn, W.: Some Reflections on Coronary Bypass Surgery, Circulation 45: 869, 1972. 19 McNamara, 1. J., Molot, M. A, Stremple, J. F., et al.: Coronary Artery Disease in Combat Casualties in Vietnam, J. A M. A 216: 1185, 1971. 20 Krauss, K., Hutter, A. M., Jr., and DeSanctis, R. W.: Acute Coronary Insufficiency: Clinical Course and Follow-up (Abstr.), Circulation 44: 102, 1971 (Suppl. II). 21 Auer, J., Johnson, D., Flernrna, R., Tector, A, and Lepley, D.: Direct Coronary Artery Surgery for Impending Myocardial Infarction (Abstr.), Circulation 44: 102, 1971 (Supp!. 11). 22 Wood, P.: Acute and S, bacute Coronary Insufficiency, Br. Med. J. I: 1779, 1961. 23 Lambert, c., Adam, M., Geisler, G. F., Verzosa, E., Nazarian, M., and Mitchel, B. F., Jr.: Emergency Myocardial Revascularization for Impending Infarctions and Arrhythmias, J. THORAc. CARDIOVASC. SURG. 62: 522, 1971. 24 Proudfitt, W., Shirey, E., and Sones, M.: Distribution of Arterial Lesions Demonstrated by Selective Cinecoronary Arteriography, Circulation 36: 54, 1967. 25 Beamish, R., and Storrie, V.: Impending Myocardial Infarction, Circulation 21: 1107, 1960. 26 Solomon, H., Edwards, A, and Killip, T.: Prodromata in Acute Myocardial Infarction, Circulation 40: 463, 1969. 27 Lopes, M., Spivack, A., Harrison, D., and Schroeder, J.: Prognosis of Noninfarction Coronary Care Unit Patients (Abstr.), Am. J. Cardiol, 31: 144, 1973. 28 Conti, R., Bramley, R., Pitt, B., and Ross, R.: Unstable Angina: Morbidity and Mortality in 57 Consecutive Patients Evaluated Angiographically (Abstr.), Am. J. Cardio!. 31: 127, 1973. 29 Sustaita, H., Chatterjee, K., Matioff, J., and Swan, H.: The Rationale for Surgery in Preinfarction Angina (Abstr.), Am. J. Cardiol, 31: 160, 1973. 30 Segal, B., Likoff, W., Brock, H., Kimberes, D., Najma, M., and Linhart, J.: Saphenous Vein
Preinfarction angina pectoris
94 1
Bypass Surgery for Impending Myocardial Infarction, J. A M. A 223: 767, 1973. 31 Pittman, D.: American College of Cardiology Presentation, Washington, D. c., February, 1973.
Discussion DR. JOHN E. HUTCHINSON New York. N. Y.
I congratulate the authors for emphasizing the point that some patients with preinfarction anginal syndromes are true surgical emergencies. We have had several patients in whom prompt surgical intervention has undoubtedly salvaged myocardial tissue that was destined for necrosis. In some patients, we have considered urgent or immediate operation as analogous to operations for acute emboli to the femoral artery. There is a golden time interval before transmural infarction occurs and muscle necrosis becomes irreversible. I would like to describe one patient whom we treated. A 44-year-old man was admitted to our coronary care unit with severe substernal chest pain, an unstable electrocardiogram, and normal serum enzyme determinations. Emergency coronary arteriography was performed. There was some aneurysmal dilatation of the upper one third of the right coronary artery, but no major obstructions. On injection of the left main coronary artery, we found an extremely severe stenosis of the proximal anterior descending coronary artery with a normal appearing circumflex system. The contractility of the anterior left ventricle was markedly impaired. An emergency operation was performed 2 hours after the study. Striking improvement in left ventricular contractility was noted on the operating table immediately after institution of flow through a vein bypass to the anterior descending coronary artery. A repeat angiocardiogram, performed 15 days after operation, showed that the vein graft to the middle third of the anterior descending coronary artery was patent. When the left main coronary artery was injected, there was no filling of the distal anterior descending. After the operation, there was marked improvement in left ventricular contractility in the distribution of the anterior descending coronary artery. Dramatic cases like this one certainly confirm the opinion that some patients with preinfarction angina are true surgical emergencies and should be operated upon in the next hour or so, rather than the next day, 2 days, or the next week. DR. WILLIAM B. FORD Pittsburgh, Pa.
I congratulate Dr. Goodin and the co-authors for their work. We also are aware of the opinion
The Journal af
942
Goodin et al.
that this clinical entity is a surgical emergency. Without coronary cine studies, of course, surgical intervention is not justified. In general, these patients are not in immediate danger of death, but they may be in immediate danger of myocardial infarction. Once a diagnosis is made, we believe that 6,000 units of heparin should be given intravenously at once and continued every 4 hours. Then, the cine studies and other diagnostic studies can be done. Several years ago Drs. Beamish, Vakil, and Nichols used heparin in patients who had the preinfarction syndrome, comparing the results with those obtained in a control group. They found that morbidity and mortality rates decreased in the patients who were given heparin. Of course, we do not believe that heparin is good for long-term therapy of coronary arterial occlusive disease. We have treated 14 patients with intravenous heparin before operation and then have performed the grafting procedures. All patients were operated upon within 72 hours after the clinical diagnosis was made. There were no deaths. Thirteen patients were relieved of their angina. The fourteenth patient developed severe precordial pain on the tenth postoperative day. The cine study showed that both grafts were patent, and I week later the pain regressed. We did not understand the cause of her pain. We believe that the use of heparin will change the preinfarction syndrome patient from a surgi-
Thoracic and Cardiovascular Surgery
cal emergency to one of urgency. Therefore, we can avoid the rush and the tension of a procedure that should be done immediately. DR. GOODIN (Closing) I would like to thank Drs. Hutchinson and Ford for their comments. We have not routinely used anticoagulants in the medical therapy of pre infarction angina. When we anticipate surgical intervention, we try to avoid Inderal therapy. Many people including ourselves feel that Inderal is an excellent drug in the management of angina pectoris. We usually institute Inderal therapy on admission in patients with severe angina pectoris. However, we prefer not to operate upon patients who have been on Inderal in the previous 48 to 72 hours, and this can create a dilemma. Basically, if pain persists and we make a diagnosis of preinfarction angina, we recommend surgery and discontinue Inderal therapy. In regard to preoperative abnormalities disclosed by left ventriculography, it would appear that if we are dealing with a true preinfarction state and the patient has not had prior myocardial infarctions, we should reasonably expect the hypokinesis and akinesis to disappear after revascularization of the involved segments. Thus, in the preinfarction angina patient, hypokinesis and akinesis do not necessarily preclude the possibility of effective revascularization surgery.
Introductory abstracts
Beginning in January, 1974, it is requested that each article begin with a brief abstract. Authors submitting articles on or after September 1, 1973, should supply an abstract of 150 words or less.