Management of preinfarction angina

Management of preinfarction angina Evaluation and comparison of medical versus surgical therapy in 43 patients Short-term results of aggressive surgical management were compared with results of medical management in forty-three patients with preinfarction angina admitted to the coronary-care unit (CCU) over an 18 month period. These patients were selected from 1,609 consecutive admissions to the CCU because they met strict criteria for preinfarction angina: severe chest pain at rest, ST-segment elevation or depression during pain which subsided rapidly after cessation of pain, and normal serum enzymes (CPK, SGOT, and LDH). Twenty-three patients had coronary angiography, done with operating room and pump standby. One patient, who had total occlusion of the left main coronary artery, died during the study. Twenty-one of the remaining patients were considered surgical candidates, and were treated immediately after angiography with 1 to 3 vein bypass grafts. There was one late postoperative death and, of the 20 survivors, 2 had ECG evidence of acute myocardial infarction and one had mild angina at time of discharge. In contrast, of the 21 patients treated medically, 13 sustained acute MI, resulting in 8 instances of congestive heart failure and 4 cases of ventricular fibrillation. Four patients died in cardiogenic shock. With the use of rigid criteria, a small subgroup of patients with variant angina at high risk of developing AMI has been identified and categorized as having preinfarction angina. Our experience suggests that aggressive surgery immediately following coronary angiography offers a lower incidence of MI, morbidity, and death than does medical management.

George Berk, M.D.,* Martin Kaplitt, M.D., Vellore Padmanabhan, M.D., Stephen Frantz, M.D., John Morrison, M.D., and Stephen J. Gulotta, M.D., F.A.C.C, Manhasset, N. Y.

A here are few terms in the medical literature more surrounded with ambiguity than "preinfarction angina." This is exemplified by the variety of terms used to identify this group of patients who present with an altered anginal pattern and have a high risk of myocardial infarction and its complications. Among the terms used to describe this entity are "impending coronary occlusion," 1 "intermediate coronary syndrome," 2 "unstable angina," 3 "impending myocarFrom the Department of Medicine, Division of Cardiology, and the Department of Surgery, Division of Thoracic and Cardiovascular Surgery, North Shore University Hospital, Manhasset, N. Y., and the Department of Medicine, Cornell University Medical College, New York, N. Y. Received for publication April 3, 1975. Address for reprints: Stephen J. Gulotta, M.D., Division of Cardiology, North Shore University Hospital, Community Drive, Manhasset, N. Y. 11030. *Westchester Heart Association Trainee 1973-74; Nassau Heart Association Research Fellow 1974-75.

1 10

dial infarction,"4 "coronary failure," 5 "crescendo angina," and "accelerated angina pectoris." 6 With the availability of direct saphenous vein coronary artery bypass in recent years, enthusiasm for surgical intervention in this high-risk group of patients has resulted in much use of this therapeutic modality. 7-16 Nevertheless, the variability in definitions and lack of general agreement as to what constitutes preinfarction angina have made objective assessment of surgical therapy quite difficult. The principal difficulty lies in the fact that these syndromes have been defined by very subjective clinical criteria, varying from "new or altered ischemic cardiac pain" 6 to relatively complex multifactoral definitions.17 Additionally, the immediate and remote natural history of the syndrome remains controversial, and the risks of diagnostic intervention and major surgery in patients with severely compromised myocardial vascular supply are uncertain. With the above considerations in mind, this study

Volume 71 Number 1 January, 1976

was undertaken to: (1) precisely define a high-risk subgroup of coronary patients with rigorous criteria for preinfarction angina; (2) assess the short-term prognosis of such a group managed medically; (3) gauge the risk and efficacy of aggressive diagnostic evaluation and surgical therapy in these patients. Materials and methods All admissions with the diagnosis of ischemic heart disease to the ICU or CCU of North Shore University Hospital from January, 1973, to June, 1974, were evaluated for inclusion in the study (1,609 patients). Of these, all patients considered to have sustained an acute myocardial infarction either on admission or during the first 48 hours of hospitalization were excluded from consideration, as were patients without convincing evidence of coronary arterial disease by history or electrocardiogram (ECG). Criteria for acute myocardial infarction included new, persisting Q waves or new ST-segment and T-wave abnormalities on the ECG, transient elevation of cardiac enzymes (SGOT > 55, CPK > 200, LDH > 200) with subsequent return to baseline, and confirmative historical and laboratory parameters. Also excluded from the study were patients with left bundle branch block or significant hepatic dysfunction, and those with disease of other organ systems which might obscure the diagnosis of acute MI. This left a pool of patients with new or altered ischemic cardiac symptoms who, at the end of 48 hours of hospitalization, had not suffered myocardial infarction. Of this group, the following specific criteria were said to constitute preinfarction angina: (1) change in pre-existing anginal pattern or new onset of classical symptoms of angina pectoris; (2) severe chest pain occurring at complete bed rest; (3) ECG changes occurring at the precise moment of chest pain and reverting completely to a pre-existing pattern no longer than 30 minutes after cessation of pain; the changes included significant ST-segment elevation, ST-segment depression of 2 mm. or more, transient bundle branch block, or transient third-degree heart block; (4) no ECG or enzymatic evidence of acute myocardial infarction. All of the above criteria had to be met for the patient to be included in this study. During the first 6 months of the study all patients who fulfilled the above criteria (an initial group totalling 13 patients) were treated medically with oxygen, complete bed rest, continuous monitoring in a CCU, and sublingual nitrates and propranolol in varying dosages as determined by the private cardiologist. Cardiac catheterization and coronary angiography were not performed in this group, as these

Preinfarction angina

11 1

procedures are considered part of aggressive management with implications of imminent surgery. Because of the initial poor results with the above medically managed group, patients fulfilling the criteria for preinfarction angina over the following 21 months were advised to undergo cardiac catheterization and coronary angiography followed by immediate bypass surgery if appropriate. Eight patients did not accept the recommendation and were treated medically in the manner described above. Twenty-two patients underwent angiography and bypass surgery. Clearly, no attempt was made to randomize these patients, but catheterization and surgery were performed unless the patient, or his physician, refused this mode of therapy. The fact that the eight patients who fell into the latter category followed clinical courses similar to our initial group of 13 patients suggests that little, if any, bias was introduced by the lack of randomization. In the surgically managed patients, the mean time from diagnosis to catheterization was 5 days, during which time medical management as judged optimal by the private physician was utilized. Right and left heart catheterization, left ventriculography, and selective coronary angiography were performed in the postabsorptive state under mild pentobarbital sedation. The right heart was entered via the left femoral vein or right basilic vein. A platinum-tipped endhole catheter was used for pressure measurements and for pacing should it become necessary during the procedure. Left heart catheterization, left ventriculography, and coronary angiography were performed by the Judkins technique via the left femoral artery or by the Sones technique via the right brachial artery. Intracardiac and intravascular pressures were measured with P23db Statham strain gauges and recorded with a DR.-12 Electronics for Medicine recorder. Cardiac output was determined by the indicator-dilution technique with indocyanine green dye and a Gilford densitometer. Cine studies were performed by means of a Phillips C-arm fluoroscopic unit or a GE Fluorocon, at 60 frames per second, with 35 mm. SF-2 Dupont or Kodak XX negative film. Left ventriculography was performed in a 30 degree right anterior oblique projection. Selective coronary angiography was done in the AP, RAO, and LAO projections by the Judkins or Sones technique. The above studies, for the most part, were done in the operating room with the entire cardiac team on standby. The cardiopulmonary bypass apparatus was in the room and primed with saline. Twelve units of cross-matched whole blood were available. All patients with high-grade occlusive lesions deemed amenable to

The Journal of Thoracic and Cardiovascular Surgery

1 1 2 Berk et al.

Table I. Preinfarction angina-—risk factors Sex

Medical (21)* Surgical (22)*

Age

M

F

Diabetes

Hypertension

Family history

Lipid abnormality

Smoking

Cardiomegaly

Prior Ml

59 53

19 19

2 3

4/21 4/22

9/21 12/22

11/21 11/22

1/21 1/22

13/21 14/22

3/21 2/22

5/21 7/22

*One patient had two discrete preinfarction episodes 8 months apart and was included in both groups.

bypass surgery (defined as greater than 85 per cent stenosis of a proximal vessel as gauged by at least three observers) were then treated with one, two, or three saphenous vein grafts. Surgery was done within 12 hours following angiography in the majority of patients, and within 36 hours in 19 of the 22 cases. Surgery was delayed 5, 7, and 21 days, respectively, in the additional three patients at the discretion of the private physician. Surgically and medically treated patients were compared as to age, sex, prior MI, and risk factors (diabetes, hypertension, family history of coronary artery disease, lipid abnormalities, smoking, and cardiomegaly). Diabetes was defined as abnormal glucose tolerance test (peak blood glucose greater than 160 mg. per 100 ml. after 60 minutes) with or without glycosuria. Hypertension was defined as consistent elevation in systolic blood pressure over 140 and/or diastolic blood pressure over 90. Lipid abnormalities included serum cholesterol greater than 300 mg. per 100 ml. and triglycerides greater than 120 mg. per 100 ml. Smoking of a significant degree was defined as more than one pack a day for over 10 years. Cardiomegaly meant a cardiothoracic ratio of greater than 0.5. The results of medical and surgical therapy were compared in terms of the following: types of preinfarctional ECG change, incidence of myocardial infarction, and occurrence of congestive heart failure, shock, and ventricular fibrillation. Both groups were also compared as to symptomatology and sequelae on short-term follow-up (varying from 8 to 24 months). Congestive heart failure was defined as the occurrence of two or more of the following: pulmonary vascular congestion on x-ray, basilar rales without evidence of infection, and ventricular gallop. Shock consisted of systolic blood pressure less than 85 for at least 3 consecutive hours, oliguria (less than 15 c.c. of urine per hour) for the same period of time, peripheral vasoconstriction, and altered state of higher integrative function. In addition, surgical patients were evaluated as to the incidence of post-pericardotomy syndrome, defined as typical pericarditic chest pain, fever, elevated sedimen-

tation rate, and variably including pericardial friction rub and cardiac arrhythmias. Results Table I compares risk factors in medically and surgically treated patients. The medically treated group averaged 59 years of age and the surgical group averaged 53. There was a marked male preponderance in each group, with only three women in the 22 surgical patients and two in the 21 member medical group. By far the most prevalent risk factors in both groups were smoking, family history of coronary arterial disease, and significant hypertension. These occurred in approximately 50 per cent of both groups, with no significant difference in incidence. Diabetes occurred in four patients from each group and hyperlipidemia occurred in only one patient from each group. Prior infarction was present in 7 of the 22 surgically treated patients and 5 of the 21 medically treated patients; cardiomegaly on standard chest x-ray was noted in two surgical and three medical patients. Again, there was no significant difference in the incidence of these risk factors between the two groups. Medical treatment. Table II summarized the results of medical therapy in 21 patients. Preinfarction ECG changes were quite variable: 10 patients had STsegment elevations, five of which were related to the inferior wall and four to the anterior or anterolateral wall, with one patient showing elevations in both areas. Ten patients had ST-segment depressions of 2 mm. or more; five of these were related to the anterolateral wall, four to the anterior wall, and one to the inferior wall. An additional patient had deep T-wave inversions in V|_ 4 . There was no consistent relationship between type or location of preinfarction changes and subsequent course or prognosis; specifically, ST-segment elevations did not carry a worse prognosis than depressions. Thirteen of the 21 medically treated patients evolved acute infarctions, as documented by new Q waves and appropriate enzyme elevations. As might be expected, the area of infarction correlated in all cases with the area of ST-segment change in the preinfarction state. The time between documentation of

Volume 71 Number 1 January, 1976

Preinfarction angina

l 1 3

Table II. Results of medical therapy

Preinfarction ECG change

Developed MI

elev. elev. dep. dep. dep.

No AMI ALMI AMI No

S T d e p . I , a V L , V5_6

ALMI

59/F

STelev. II, III, a V F , transient 3° HB

No

No No No

47/M 72/M 47/M

ST dep I, aV L , V 4 _ 6 S T d e p . I , a V L , V5_6 ST dep. V,_ 3

No ALMI No

No No No

No No No

76/M 49/M 59/M

T inv. V,_ 4 ST elev. 2, 3, aV F ST dep. V,_ 3

AMI No ASMI

M. B.

No

Yes

63/M

ST elev. 2, 3, aV F

DMI

I. W. F. B. E. S. J. J. W. H.

No No No ALMI No

No No No No No

57/M 66/M 59/M 69/M 67/M

STelev. ST elev. ST elev. ST dep. ST elev.

DMI No No ALMI DMI

W. N.

DMI

No

62/M

S T e l e v . V,_ 3 , II,

47/M

III, a V r ST dep. II, III, a V F ,

Patient

Prior Ml

Cardiomegaly

Agel sex

R. H. A. H. M.

AMI No AMI No No

Yes No Yes No No

63/M 57/M 57/M 64/M 47/F

ST ST ST ST ST

E. H.

No

No

47/M

F. F.

No.

No.

R. C. L. B. P. G.

No ALMI No

B. H. T. L. M. G.

G. R. S. H. W.

J. P.

No

No

V2-6 I, V 2 _ 5 I, aV L , V 4 _ 6 V2_6 V3_4

2, 3 , aV F V,_ 3 V,_ 3 V2-6 2, 3, aV F

Days from preinfarction to MI

Followup period (mo.)

CHF

Shock

VF/VT

2 2 5

No No Yes Yes No

No No Yes No No

No No Yes No No

Intermittent angina Asymptomatic Died acute ALMI day 4 Intermittent angina Asymptomatic; angiography showed 90% stenosis obtuse marginal, severe spasm RCA

2

No

No

Yes

Intermittent angina; elective surgery (LAD bypass) 2 wk. later; intermittent angina, milder than preoperative

6

No

No

No

6

—

Intermittent angina; elective angiography showed totally normal coronaries

No No No

No No No

No No No

12 14

—

8

2

No No Yes

No No No

No No No

3

Yes

No

No

3

4 13

Yes No No Yes Yes

No No No No Yes

No No No No Yes

AMI

3

Yes

Yes

Yes

Asymptomatic Asymptomatic Second episode of preinfarction treated surgically 8 mo. later Intermittent angina Lost to follow-up Sudden death after discharge (1 wk.) Intermittent angina, compensated CHF Asymptomatic Asymptomatic Intermittent angina Intermittent angina Died day 15 of acute MI Intermittent angina

DMI

2

Yes

Yes

Yes

Died acute DMI day 3

V5-6

3

— —

Current

status

12 12

— 16 12

18 2

— 19 12 12 17 15

— 12

"

Legend: ALMI, anterolateral wall myocardial infarction; AMI. anterior wall myocardial infarction; ASMI, anteroseptal myocardial infarction; CHF. congestive heart failure; dep.. depression; DMI. diaphragmatic myocardial infarction; elev.. elevation; HB. heart block; inv.. inversion; LAD. left anterior descending coronary artery; MI. myocardial infarction; RCA. right coronary artery; VF/VT. ventricular fibrillation/ventricular tachycardia.

preinfarction and evolution of acute MI varied from 2 to 13 days, with an average of 4 days. In terms of complications, nine of the 13 patients who evolved infarctions also developed heart failure requiring therapy with digitalis and/or diuretics. Five of the 13 developed ventricular tachycardia or fibrillation requiring DC countershock. Four suffered cardiogenic shock, resulting in three deaths. An additional

patient died suddenly 1 week after hospital discharge, presumably of a cardiovascular event. Of the 17 survivors, nine continue to experience significant anginal symptoms on follow-up ranging up to 19 months. An additional patient experienced a second episode of preinfarction 8 months later and was treated surgically. Three patients underwent elective cardiac catheterization at a later date. One had totally normal

The Journal of Thoracic and Cardiovascular Surgery

1 1 4 Berk et al.

Table III. Results of surgical therapy Cardiomegaly

Age I sex

No

No

49/M

ST elev. V,.

P. R.

No

No

63/M

A. W.

No

No

55/M

ST dep. II, III, aV F , V5_6 ST dep. II, III, aV F ; ST elev. V,_ 3

A. M.

ALMI

Yes

54/M

S T d e p . I , a V L , V2_6

W. S.

No

No

46/M

L. E. H. K.

No DMI

No No

61/F 60/M

ST dep. II, III, a V F , V 5 _ 6 ; ST elev. II, III, a V F ST elev. V 2 _ 5 S T d e p . I, a V L , V 4 _ 6

R. S.

DMI

No

53/M

C. H.

ALMI

Yes

63/M

ST elev. II, III, a V F , V 5 _ 6 ; then VT ST dep. V 2 _ 6

W. D. B. K. J. B. R. F. B. G. D. R. M. T. E. F.

No No DMI No No No ASMI No

No No No No No No No No

69/M 48/M 63/M 53/M 44/M 46/M 53/M 55/F

ST elev. II, III, a V F ST dep. V 2 _ 6 Transient 3° HB Transient LBBB ST elev. II, III, a V F ST elev. II, III, a V F S T d e p . I , a V L , V5_6 T wave inv. V 2 _ 6

G. N.

DMI

No

40/M

S T d e p . II, III, a V F ,

No No

No No

53/M 59/M

ST elev. V,_ 4 S T d e p . II, III, a V F ,

48/M 47/M 37/F

V 5 -6 T inv. V,_„ ST dep. V , ^ 6 STdep. l,aVL,V4_6

Patient

Prior MI

J. S.

M. D . * A. N. T. D. P. G. B. K.

No No No

No No No

Preinfarction ECG changes

v5-6

Angiographic findings

SVBG

MI

CHF

LAD

No

No

Died during catheterization LAD

No

No

90% prox LAD, 9 0 % mid-RCA, 9 0 % prox circumflex 9 5 % ostium RCA

LAD

No

No

RCA

No

No

60% prox R C A , 9 5 % prox L A D 100% prox RCA; L A D 100% at origin; 100% atrial circumflex, 90% prox. obtuse 9 5 % ostium RCA

LAD LAD

ASMI No

No No

RCA

No

No

100% prox RCA, 100% obtuse, 9 0 % prox L A D 9 5 % ostium RCA Single ostium; 9 0 % L main, 9 0 % L A D 90% prox L A D 90% L main, 9 0 % prox LAD 100% prox LAD, 9 0 % prox RCA 9 5 % prox RCA 9 5 % prox L A D , 80% prox CIRC 85% prox RCA; 70% prox LAD; 100% mid-LAD Diffuse disease L A D , RCA; 90% prox LAD, 9 0 % prox CIRC Diffuse triple vessel disease 90% L main, 90% prox LAD; two 9 0 % lesions RCA 90% prox LAD; 80% RCA 100% RCA, 90% prox LAD, 90% obtuse 9 5 % large 1st diagonal

LAD

No

No

RCA LAD, CIRC LAD LAD RCA RCA L A D , CIRC RCA, LAD

No No No No DMI No No No

No No No No No No No No

LAD, CIRC

No

No

Two 85% lesions prox LAD, diffuse RCA disease 100% left main, 90% distal RCA 95% prox LAD, diffuse RCA disease

No surgery done LAD, RCA (with gas No endarterectomy) No LAD, RCA No RCA, LAD, CIRC 1st diagonal

No

No No No No

Legend: AF, atrial fibrillation; ALMI, anterolateral wall myocardial infarction; ASMI, anteroseptal myocardial infarction; CHF. congestive heart failure; CIRC, left infarctioi : clcv.. elevation; HB heart block; inv.. inversion; LAD, left anterior descending coronary artery; LBBB. left bundle bran ch block; prox. proximal; RCA . right *Excluded from study.

coronaries (patient F. F.), another had a proximal 90 per cent occlusion of a small obtuse marginal branch and severe proximal spasm of the right coronary (patient M. W.), and the third (patient E. H.) had severe three-vessel disease (subsequently treated by bypass surgery). Surgical treatment. The results in the surgically treated group are outlined in Table III. Again, the preinfarctional ECG changes were very variable: ST-segment elevations occurred in nine patients (two of whom also had ST-segment depressions at a different time); five were related to the inferior wall and

four to the anterior wall. Ten patients had ST-segment depressions alone, four related to the anterolateral wall and three each to the anterior and inferior areas. Additionally, two patients had deep T-wave inversions in the anterior leads, one had third-degree heart block, and another exhibited transient left bundle branch block. All patients studied had high-grade proximal stenosis of at least one major vessel; 15 of the 21 patients who underwent surgery had double- or triple-vessel disease. Only one patient (patient M. D.), with severe three-vessel disease and poor runoff, was considered inoperable and excluded from the study.

Volume 71 Number 1 January, 1976

Arrhyth-

Post pericardotomy

Preinfarction angina

Current

status

Follow-up period (mo.)

rtsyiiipiuumuc

11

14

17

No

No

No

No

No

No

Asymptomatic (postop. course complicated by DT's, acute renal failure sepsis) Intermittent angina (on Inderal 80 mg. q. d.) Asymptomatic

No No

No No

Asymptomatic Sudden death 9 days postop

No

No

Asymptomatic

No

No

Asymptomatic

10

No AF No No No No No AF

No No No No No No No Yes

Asymptomatic Asymptomatic Asymptomatic Asymptomatic Asymptomatic Asymptomatic Asymptomatic Asymptomatic

6 15 19 18 22 18 18

No

No

Asymptomatic

16

No evidence No

MI No

Asymptomatic Asymptomatic

12 12

No No No

No No Yes

Asymptomatic Asymptomatic Asymptomatic

17 19

7 9

circumflex coronary artery: dep.. depression: DMI. diaphragmatic niyocardial coronary artery: SVBG. saphenous vein bypass grafts; VT. ventricular.

Of the 21 patients receiving 29 grafts, two documented infarctions (as judged by new Q waves) were noted in the postoperative period. These were unassociated with heart failure or arrhythmia. Two patients had transient, significant atrial tachyarrhythmias; two had a postpericardiotomy syndrome. There was one death in the group: patient H. K., who had severe triple-vessel disease with poor runoff. Only the distal LAD could be bypassed. He died suddenly 9 days after surgery, presumably of a cardiovascular event. One patient (patient P. R.) died during the catheterization. This patient had the extremely rare

11 5

lesion of total left main coronary occlusion,18 with 90 per cent stenosis of the distal right coronary and small fine collaterals supplying the anterior wall from the posterior interventricular artery. It is noteworthy that this patient, as well as five others, had episodes of transient ventricular tachycardia during the catheterization, demonstrating the marked cardiac irritability of this group. In marked contrast to the medical group, only one patient of the 20 survivors had significant angina on follow-up varying from 6 to 22 months. Table IV summarizes the surgical and medical results in our patients with rigorous criteria for preinfarction angina. Twenty of the 22 surgically managed patients remain alive, and 19 of these are pain-free; 17 of the 21 medically managed patients remain alive, but more than half have sustained an acute MI and an equal number continue to experience significant angina. Discussion There has been a great deal of controversy in the literature as to the prognosis of "preinfarction angina" in terms of morbidity and death. A recent article17 asserts that "mortality rates for patients with unstable angina treated medically range from 3 to 40 per cent." The marked disparity in these figures is obviously due in great measure to the rigor with which one defines the preinfarction state. For example, Chalmers19 summarized the results of medical therapy in nearly 1,000 patients reported by five different groups and found a mortality rate varying from 0 to 27.7 per cent. Diagnostic criteria in the groups with low mortality rates equated to "altered pain." Kraus, Hutter, and DeSanctis20 reported an 86 per cent survival rate of preinfarction patients treated medically over 1 year, but defined preinfarction angina as "pain lasting over 30 minutes" without evidence of MI. Fulton and associates,21 using altered chest pain as their criterion, reported only a 14 per cent incidence of acute infarction over an 18 month follow-up. It is apparent from the definitions utilized in the above studies that this is a totally different group of patients from those we are following. When one becomes more precise in defining the preinfarction state, however, the natural history of this entity becomes far more grim. Scanlon and his co-workers6 took a group of patients with "accelerated angina pectoris" (increasing frequency and severity of anginal attacks, rest or nocturnal angina, "often" ischemic ST- and T-wave changes with pain) and defined a selected high-risk subgroup on the basis of significant lesions on coronary angiography. On

The Journal of Thoracic and Cardiovascular Surgery

1 6 Berk et al.

Table IV. Summary Therapy

No. of patients

Acute MI

Death

CHF

Shock

VF

Angina on follow-up

Medical Surgical

21 22

13 4*

4 2*

9 0

4 0

5 2*

9 (of 17 survivors) 1 (of 20 survivors)

i n c l u d i n g the death during catheterization and the sudden death on day 9.

medical therapy 59 per cent suffered an acute MI, with a 27 per cent mortality rate in this group. Additionally, nine of the 57 patients considered for surgery had an MI preoperatively. Gazes and associates,22 in a 10 year retrospective study, compared a group with preinfarction angina defined as "progressive crescendo angina and pain at rest" with a "high-risk subgroup" who, in addition to progressive and rest angina, had transient ECG changes occurring during episodes of pain. In the less rigorously defined group, 21 per cent developed an acute MI in the 8 months after diagnosis, with an associated mortality rate of 41.4 per cent. The high-risk subgroup, however, had a 35 per cent incidence of acute MI in the first 3 months following diagnosis, with an associated mortality rate of 63 per cent and a 12 month survival of only 57 per cent. Our experiences in a brittle, high-risk subgroup closely parallel those of Scanlon and Gazes. On medical management 62 per cent of our patients suffered an acute MI, with an immediate mortality rate of 30 per cent in this group. Our "medical management" consisted of propranolol in varying dosages, round-the-clock sublingual vasodilators, and all the ancillary measures and supportive care provided by a modern CCU. When one examines the surgical experience in preinfarction angina the definition is again critical. For example, Flemma and associates23 reported 78 of 80 patients "improved" after surgery and only a 2.5 per cent operative mortality rate, but defined preinfarction angina as "increased angina at rest . . . poorly responsive to medical therapy." Auer and associates,24 in a similarly defined group, reported no infarctions or deaths in 41 consecutive patients. Again, these studies deal with a patient population quite distinct from ours. The surgical experience with a high-risk subgroup is somewhat limited and somewhat contradictory. Miller and associates25 reported a well-selected group of 67 patients with an immediate mortality rate of 10.4 per cent and a late death rate of 3.3 per cent. Conti and associates17 reported on the results of surgery in a rigorously defined group of patients with the preinfarc-

tion syndrome, with an operative mortality rate of 22 per cent. The relatively high mortality rates in these two studies are in marked contrast to the data of Bertolasi and associates.26 The latter authors reported on 24 surgically treated patients, and compared the mortality rate with that of a medically managed group. In the surgical group only 2 of 24 died postoperatively, in contrast with 7 out of 20 dead in the medical group. The criteria for preinfarction angina were: recurrent angina unrelated to effort, normal enzymes, no extracardiac problems, and no pump failure. Additionally, two "minor" criteria were also needed: little or no response to nitrates, transitory ECG changes of ventricular depolarization, transitory arrhythmias, or less than 1 month between onset of angina and entry into the study. It can be seen that some patients meet our rigorous criteria while others do not, depending on the "minor" criteria in each case. Thus, despite the fact that the results of their study agree in substance with ours, the patients involved may not be nearly as unstable as those in our group or those reported by Conti and associates.17 Our initial experience, as summarized previously, shows one catheterization death and one early death in 22 patients treated with aggressive diagnostic evaluation and surgical management. On this basis, it is believed that surgical therapy, at least as applied to a high-risk subgroup, is associated with significantly less death and morbidity than medical management. The variance of these results from those of Conti, dealing with similarly defined patients, is difficult to explain, but may be due in part to the presence of unrecognized myocardial infarction in his group resulting in an increased risk of surgery. It is noteworthy that the period between angiography and surgery in Conti's group averaged 6.3 days. In our study the angiography was considered to be the first step in aggressive management and was done in the majority of cases with pump standby. Most patients underwent surgery immediately following angiography, possibly minimizing the number of patients suffering small infarctions during or subsequent to the catheterization, and decreasing the early surgical mortality rate.

Volume 71 Number 1 January, 1976

Conclusion Aggressive management with cardiac catheterization and coronary angiography immediately followed by saphenous vein bypass was utilized in 22 cases of rigorously denned preinfarction angina. In this group there was one death during the catheterization, one late death, and only one patient with residual angina on follow-up. These results were contrasted with those in a similar group treated medically in which there was a high incidence of acute infarction, death, and residual angina. It is concluded that aggressive angiography and surgical management may offer significant therapeutic advantages over medical management in the preinfarction state. In this brittle group of patients, coronary angiography in the operating room followed by immediate surgery may have been of particular importance in contributing to the low mortality and morbidity rates. REFERENCES 1 Sampson, J. J., and Eliaser, M , Jr.: Diagnosis of Impending Acute Coronary Artery Occlusion, Am. Heart J. 13: 675, 1937. 2 Graybiel, A.: The Intermediate Coronary Syndrome, U. S. Armed Forces Med. J. 6: 1, 1955. 3 Fowler, N. O.: "Preinfarctional" Angina. A Need for an Objective Definition and for a Controlled Clinical Trial of Its Management, Circulation 44: 755, 1971. 4 Lawrence, G. H.: Coronary Revascularization for Impending Myocardial Infarction (Abst.), Circulation 44 (Suppl. II): 11-190, 1971. 5 Freedberg, A. S., Blumgart, H. L., Zoll, P. M., and Schlesinger, M. J.: Coronary Failure: The Clinical Syndrome of Cardiac Pain Intermediate Between Angina Pectoris and Acute Myocardial Infarction, J. A. M. A. 138: 107, 1948. 6 Scanlon, P. J., Nemickas, R., Moran, J. F., Talano, J. V., Amirparviz, F., and Pifarre, R.: Accelerated Angina Pectoris: Clinical, Hemodynamic, Arteriographic and Therapeutic Experience in 85 Patients, Circulation 47: 19, 1973. 7 Bolooki, H., Vargas, A., Ghahramani, A., Sommer, L. D., Orvald, T., Juda, J. R., and Boccabella, K.: Aorto-coronary Bypass Graft for Preinfarction Angina, Chest 61: 247, 1972. 8 Cohen, L. H., Fogarty, T. J., Daily, P. O., and Shumway, N. E.: Emergency Coronary Artery Bypass, Surgery 70: 821, 1971. 9 Dumesmil, J. G., Gau, G., Callahan, J., Pluth, J. R., Danielson, G. K., and Wallace, R. B.: Emergency Revascularization With Saphenous Vein Graft, Am. J. Cardiol. 29: 260, 1972. 10 Favaloro, R. G., Effler, D. B., Cheanvechai, C , Quint, R. A., and Sones, F. M., Jr.: Acute Coronary Insufficiency: Impending Myocardial Infarction and

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angina

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Myocardial Infarction, Am. J. Cardiol. 28: 598, 1971. 11 Lambert, C. J., Mitchel, B. F., Adam, M., and Geisler, G. F.: Emergency Myocardial Revascularization for Impending Myocardial Infarctions, Chest 61: 479, 1972. 12 Linhart, J. W., Beller, B. M., and Talley, R. C : Preinfarction Angina: Clinical, Hemodynamic and Angiographic Evaluation, Chest 61: 312, 1972. 13 Pfeifer, J., Hultgren, H., Alderman, E., Angell, W., and Shumway, N.: Surgical Intervention in Impending Myocardial Infarction (abst.), Circulation 44 (Suppl. II): 11-211, 1971. 14 Robinson, W. A., Smith, R. F., Stevens, T. W., Perry, J. M., and Friesinger, G. C : Preinfarction Syndrome: Evaluation and Treatment (abst.), Circulation 46 (Suppl. II): 11-212, 1972. 15 Spencer, F. C : Bypass Grafting for Preinfarction Angina, Circulation 45: 1314, 1972. 16 Sustaita, H., Chatterjee, K., Matloff, J. M., Marty, A. T., Swan, H. J., and Fields, J.: Emergency Bypass Surgery in Impending and Complicated Acute Myocardial Infarction, Arch. Surg. 105: 30, 1972. 17 Conti, R. C , Brawley, R. K., Griffith, L. S., Pitt, B., Humphries, J. O., Gott, V. L., and Ross, R. S.: Unstable Angina Pectoris: Morbidity and Mortality in 57 Consecutive Patients Evaluated Angiographically, Am. J. Cardiol. 32: 745, 1973. 18 Tector, A. J., DeCock, D., and Lepley, D., Jr.: Left Main Coronary Artery Occlusion: Surgical Management, Cardiovasc. Dis. Bull. Texts Heart Inst. 1: 231, 1974. 19 Chalmers, T.: Randomization and Coronary Artery Surgery, Ann. Thorac. Surg. 14: 323, 1972. 20 Kraus, K. R., Hutter, A. M., Jr., and DeSanctis, R. W.: Acute Coronary Insufficiency: Course and Followup, Arch. Intern. Med. 129: 808, 1972. 21 Fulton, M., Lutz, W., Donald, K. W., Kirby, B. J., Duncan, B., Morrison, S. L., Kerr, F., and Julian, D. G.: Natural History of Unstable Angina, Lancet 1: 860, 1972. 22 Gazes, P. C , Mobley, E. M., Jr., Faris, H. M., Jr., Duncan, R. C , and Humphries, G. B.: Preinfarction (Unstable) Angina—A Prospective Study: Ten Year Followup, Circulation 48: 331, 1973. 23 Flemma, R. J., Johnson, W. D., Tector, A. J., Lepley, D., Jr., and Blitz, J.: Surgical Treatment of Preinfarction Angina, Arch. Intern. Med. 129: 828, 1972. 24 Auer, J. E., Johnson, W. D., Flemma, R. J., Tector, A. J., and Lepley, D.: Direct Coronary Artery Surgery for Impending Myocardial Infarction (abst.), Circulation 44 (Suppl. II): 11-102, 1971. 25 Miller, D. C , Cannom, D. S., Fogarty, T. J., Schroeder, J. S., Daily, P. O., and Harrison, D. C : Saphenous Vein Coronary Artery Bypass in Patients With "Preinfarction Angina," Circulation 47: 234, 1973. 26 Bertolasi, C. A., Tronge, J. E., Carreno, C. A., Jalon, J., and Ruda Vega, M.: Unstable Angina—Prospective and Randomized Study of Its Evolution, With and Without Surgery, Am. J. Cardiol. 33: 201, 1974.