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Results of aortocoronary bypass grafting in patients with subendocardial infarction: Late follow-Up
Results of Aortocoronary Bypass Grafting in Patients With Subendocardial Infarction: Late Follow-Up AGOP AINTABLIAN, MD, FACC ROBERT I. HAMBY, MD, FACC DANIEL WE&Z, MD, FACC IRWIN HOFFMAN, MD, FACC CHOUDARY VOLETI, MD, FACC B. GEORGE WISOFF, MD, FACC New Hyde Park, Jamaica and Stony Brook New York
From the Department of Medicine, Division of Cardiology and the Department of Surgery, Cardiothoracic Dlvision, Long Island Jewish-Hillside Medical Center, New Hyde Park, Queens Hospital Center Afflliatlon, Jamaica and School of Medicine. Health Sciences Center, State university of New Yak at Stony kook, stony Brook. New York. Manuscrlpt received February 8. 1978; revised manuscript received March 1, 1978, accepted March 1.1978. Address for reprints: Atop Alntablian, MD, kpartment of Medicine, Division of Cardiology, Long Island Jewish-Hill&de Medical Center, New Hyde Park, New York 11040.
Twenty-eight patients with subendocardial infarction (Group A) were compared with 28 patients with unstable angina (Group B) and 28 with stable angina (Group C) matched for age and sex. The three groups did not dtffer in prevalence of diabetes, hypertension, old infarction or duration of disease. There were no significant differences in number of diseased vessels, coronary score, abnormal left ventricular wall motion or left ventricular end-diastolic pressure. Angiograms performed 2 weeks postoperatively revealed closure of 3 of 31 grafts (18 patients) in Group A, closure of 3 of 34 grafts (17 patients) in Group B and closure of 8 of 50 grafts (22 patients) in Group C (differences not significant). Postoperative angiograms showed improved wall motion in 37 percent of Group A, 53 percent of Group B and 38 percent of Group C (dtfferences not significant). Postoperative new 0 waves appeared in one patient in Group A and in two patients in Groups B and C. There were no hospital or late deaths. In a mean follow-up period of 29 months, 88 percent of patients in Group A, 81 percent in Group B and 54 percent in Group C were asymptomatic. Thus, bypass grafting was performed with similarly low mortality and morbidity in patients with subendocardial infarction and in those with angina; more than one third of postoperative angiograms in the three groups showed improved wall motion; and late follow-up studies demonstrated functional improvement in the majority of patients in all three groups.
The course of coronary artery disease is unpredictable in any individual patient with angina pectoris. However, in recent years, studies’-5 have shown that in some patients “stable” angina passes through the stages of “unstable,” “progressive” or “preinfarction” angina before a transmural or subendocardial infarction develops. After the initial controversies concerning prognosis in surgically treated patients with unstable angina,l-5 several studies~s indicated not only symptomatic improvement but also longer survival after bypass surgery. However, Hutter et al.9 found that such patients had a greater incidence of new Q waves than medically treated patients and no improvement in survival. There is disagreement lels whether bypass surgery, in addition to alleviating symptoms, prolongs survival in patients with stable angina. Among patients with subendocardial infarction, those treated medically have shown a 10 to 37 percent rate of transmural infarction1p17 and a 0 to 18 percent mortality rate within 4 weeks1s20 and a 3 to 14 percent yearly mortality rate after hospital discharge.2@~2c~21Similarly, both a high yearly rate of transmural myocardial infarction and a high mortality rate have been found in patients who are admitted to a coronary care unit with symptoms of myocardial infarction but whose electrocardiogram did not confirm the diagnosis.22-24 In this report we present our experience with coronary bypass surgery in 28 patients with subendocardial infarction and in an equal number of patients with unstable and stable angina pectoris who were followed up postoperatively for a mean period of 29 months. Material
and Methods
Patients
Among 800 patients undergoing saphenous vein bypass graft surgery between January 1972 and July 1977 at this institution, 28 had preoperative subendocardial infarction. These patients (Group A) were compared with 28 patients
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GRAFTING FOR SUBENDOCARDIAL
INFARCTION-AINTABLIAN
ET AL.
with unstable angina pectoris (Group B) and 28 patients with stable (Group C) angina pectoris who were matched for age and sex. Almost all patients in the group with subendocardial infarction were admitted to the hospital from the emergency room with a history of chest pain lasting more than 30 minutes and findings of symmetric T wave inversion with or without S-T segment depression. They were observed in the coronary care unit to rule out transmural infarction. A few patients with similar continuous angina were transferred from the coronary care unit of other hospitals because of electrocardiographic evidence of subendocardial infarction and significant enzyme elevations. After 24 to 48 hours of observation in our hospital, if transmural infarction did not develop, coronary angiography was performed. The criteria for subendocardial infarction included (1) angina pectoris at rest lasting more than 15 minutes; (2) elevation of at least two of three serum enzymes (creatine kinase, serum glutamic oxaloacetic transaminase or lactic dehydrogenase) to at least twice normal values or greater; (3) T wave inversion or S-T segment depression, or both, lasting more than 48 hours without pathologic & waves. The criteria for unstable angina were those previously reported.3 The group with stable angina met New York Heart Associationz5 criteria for class II to IV angina pectoris without acute electrocardiographic changes and symptoms relieved with rest or sublingual nitroglycerin. Most of these patients had progressive angina. Patients were excluded if they were undergoing left ventricular aneurysmectomy, prosthetic valve replacement or repair of associated congenital heart defect in addition to bypass grafting or if they had bundle branch block. Studies Hemodynamic studies were performed after an overnight fast, after all medications except nitroglycerin and long-acting nitrates had been discontinued for at least 24 hours. Left and right heart catheterization and left ventricular and selective coronary angiography, using the Judkins2s or
Sones and Shireyz7 techniques, were performed in all patients. In quantitating left ventricular dysfunction and the patterns of left ventricular contraction, we used the techniques and principles previously reported,28 utilizing the descriptive terminology suggested by Herman et al.sg The severity and extent of coronary disease were graded according to the criteria of Bruschke et al.sO All angiograms and electrocardiograms were reviewed by two cardiologists and accepted for study only if there was complete agreement on interpretation. Twelve lead electrocardiograms were performed in each patient on admission and on the day before cardiac catheterization. In addition, patients with subendocardial infarction or unstable angina had electrocardiograms performed daily and also immediately after cardiac catheterization to rule out the occurrence of trmmural infarction during the procedure. This precaution was taken because several of the patients with subendocardial infarction had additional anginal attacks after ventriculography or coronary angiography. A normal resting electrocardiogram was defined with conventional critaria.31 Coronary revascularization tion of cardiac catheterization
was performed
after comple-
in all patients with subendocardial infarction and unstable angina with significant coronary obstruction. The patients were transferred directly from the catheterization laboratory to the operating room. Repeat left heart catheterization and selective graft angiography were performed 2 to 3 weeks after surgery in all patients giving consent.
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The American Journal d CARDIOLOGY
TABLE I Clinical Profile
Infarction no. % ii?@% Patients’
iiF@%
28
100
28
100
28
100
23
82
23
86
23
82 18
z 8
:; 29
1: 11
:: 39
1; 8
t:
:
29 11
8 3
29 11
8 6
29 21
54 25 21
11 11 6
39 39 21
9 9 10
32 32 36
Sex
Male
Female History of infarction Evidence of infarction In electrocardiogram History of hypertension History of diabetes Angina pectoris 5 years
15 ;
l In all three groups, the patients had a mean age (k standard deviation) of 53 f 8 years (range 34 to 72 years).
Results Of 800 patients with coronary artery disease who underwent saphenous vein bypass surgery, 28 had subendocardial infarction (Group A). These patients were compared with 28 patients with unstable (Group B) and 28 with stable (Group C) angina. Age, sex, prevalence of diabetes mellitus, hypertension, old myocardial infarction or duration of disease did not differ among the three groups (Table I). No significant differences in the number of diseased vessels, coronary score, abnormal left ventricular wall motion, elevated pulmonary wedge or left ventricular end-diastolic pressures were found in these three groups (Table II). Angiograms obtained 2 weeks after operation revealed closure of 3 of 31 grafts (10 percent) in 16 patients in Group A, closure of 3 of 34 grafts (9 percent) in 17 patients in Group B, and closure of 6 of 55 grafts (11 percent) in 22 patients in Group C (differences not significant). The postoperative study revealed improved left ventricular wall motion in 6 patients (37 percent) in Group A, 9 patients (53 percent) in Group B and 8 patients (36 percent) in Group C (differences not significant). Wall motion was unchanged in 8 patients (50 percent) in Group A, in 6 (35 percent) in Group B and 13 (59 percent) in Group C. Only 2 patients (13 percent) in Group A, 2 (12 percent) in Group B and l(4 percent) in Group C manifested postoperative deterioration of the left ventricular segmental wall motion. New Q waves appeared perioperatively in one patient in Group A and in two patients each in Groups B and C (difference not significant). One patient in Group B had a postoperative cerebrovascular accident with left-sided hemiplegia. Three patients each in Group B and C and one in Group A had postoperative pulmonary emboli that responded to systemic anticoagulation. A postpericardiotomy syndrome occurred in one patient each in Groups A and C, requiring steroid therapy in one.
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TABLE II Anglographic Data Group A: Subendocardial Infarction no. %
Patients Coronary artery disease Single Double Triple RCA LAD LCX LCA Abnormal LV angiogram (preop) Elevated pulmonary wedge pressure I12mmHg Elevated left ventricular enddiastolic pressure 5 12mmHa
Group 8: Unstable ,$ngintO
Zr!fF n&rgin;O
28
100
28
100
28
100
10 8
3 15 IO 16 27 20 4 21
11 54 36 57 96 71 14 75
6
21
2:
36 29 36 61 93 46 14 75
1: 19 26 20 0 16
:9” 68 93 71 0 57
2
7
2
7
3
11
14
50
11
39
11
39
l
:; 26 13
Patients in Groups A, B and C had a coronary score (mean f standard deviation) of 9 f 3, 10 f 3 and 10 f 3, respectively. LAD = left anterior descending coronary artery: LCA = left main coronary artery; LCx = left circumflex artery; LV = left ventricular; preop = preoperative; RCA = right coronary artery. l
There were no hospital or late deaths. During a mean follow-up period of 29 months (range 5 to 64), a transmural infarction developed in one patient in Group B. One patient in Group A and two in Group C underwent reoperation because of recurrence of angina pectoris at rest. At the end of the follow-up period, 68 percent of patients in Group A were in New York Heart Assocation class I and 29 percent in class II-III. In Group B, 61 percent were in class I and 36 percent in class II-III. In Group C, 54 percent were in class I and 43 percent in class II-III. Discussion Natural history of subendocardial infarction: The hospital course and subsequent follow-up of patients with nontransmural (subendocardial) infarction have shown that this entity is treacherous, with a significant incidence of transmural infarction and death.3p4*32Indeed, several studies1g-21 have indicated that the natural history of subendocardial infarction does not differ significantly from that of classic transmural infarction. Madigan et al.ls showed, in a mean follow-up period of 11 months, that of 50 patients with subendocardial infarction 46 percent had unstable angina and only 24 percent were asymptomatic with medical therapy. In 6 of 28 patients (21 percent) receiving medical therapy a transmural infarction developed, and 1 patient (3 percent) died. Levy and associates21 noted, in a mean follow-up period of 35 months, that sudden death and recurrent infarction occurred twice as often in patients with a nontransmural infarction as in those with a transmural infarction. Other&24 have reported that patients with prolonged
GRAFTING FOR SUBENDOCARDIAL
INFARCTION--AINTABLIAN
ET AL.
ischemic chest pain, but without evidence of transmural infarction, had a yearly mortality rate of 10 to 13 percent. Bypass surgery in unstable and stable angina: Recent comparisons of the incidence of myocardial infarction and long-term mortality in patients with unstable angina receiving medical therapy and in similar patients undergoing bypass surgery revealed a lower yearly mortality in the surgical group as well as greater symptomatic improvement.e,7 Whether patients with unstable angina have greater perioperative mortality is controversial.3TsJJ Surgical mortality in patients with unstable angina depends on selection and surgical expertise and thus varies greatly from institution to institution.3,32*33 The beneficial results of coronary bypass surgery in patients with stable angina remains controversial. Several reports indicated not only better symptomatic improvement in the surgical treatment group with multivessel coronary disease but also a lower yearly mortality after 2 to 7 year follow-up, when compared with nonrandomized medical treatment groups_10,11,34-38H owever, the randomized Veterans Administration Cooperative Study, after a 3 year follow-up of 310 medically treated patients and 285 with coronary bypass showed no prolongation of life in the surgical group, an operative mortality rate of 5.6 percent and a yearly mortality rate of 4 percent.13 Bypass surgery in subendocardial infarction: Our results in 28 patients indicate that coronary bypass surgery can be performed in patients with subendocardial infarction. The mortality and perioperative morbidity of this group are not different from those of patients with unstable or stable angina, and the majority of patients are asymptomatic after surgery. Bypass grafting is not recommended in acute transmural infarction because of definitely increased mortality as well as experimental evidence that reperfusion of acute infarcts leads to larger zone hemorrhage and necrosis.38 The absence of mortality in our 28 surgically treated patients with subendocardial infarction and their generally benign postoperative course differ significantly from the reported surgical experience in patients with classic transmural infarction. Clearly, the areas of infarction, although sufficient to produce diagnostic enzyme and electrocardiographic abnormalities, were not so extensive or confluent as to result in significant infarct extension after bypass surgery. The incidence rate of perioperative Q waves did not differ significantly in the group with subendocardial infarction and those with unstable or stable angina (4 versus 7 percent), suggesting that the areas of actual infarction were small. Larger areas might be expected to extend postoperatively sufficient to present as postoperative Q waves. Madigan et a1.3g reported a similar experience with surgically treated patients with subendocardial infarction. Among their 28 patients, perioperative new Q waves developed in 10.7 percent, and one patient (3.6 percent) died. In a mean follow-up period of 16 months,
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GRAFTING FOR SUBENDOCARDIAL
INFARCTION-AINTABLIAN
ET AL
78 percent were free of angina pectoris and there were no late deaths or infarctions. Perhaps the most significant observation regarding the efficacy of bypass grafting in our group with subendocardial infarction is the improved ventricular contractile pattern in 37 percent of patients, an incidence rate identical with that of the group with stable angina. None of our patients had technetium pyrophosphate
scans before or after bypass surgery. Therefore, we do not know whether such scans would have shown any difference between the group with subendocardial infarction and that with stable angina. If the results in this small series are extended and confirmed, coronary bypass grafting could be considered an effective method for preserving ischemic myocardium, relieving symptoms and prolonging life in patients with subendocardial infarction.
References 1. Gazes PC, Mobley EW Jr, Farls HW Jr, et al: Preinfarction (unstable) angina-a prospective study-ten year follow-up. Prognostic significance of electrocardiographic changes. Circulation 48~331-337, 1973 2. Fish1 SJ, Herman MV, Gorlln R: The intermediate coronary syndrome: clinical, angiographic and therapeutic aspects. N Engl J Med 288:1193-1198, 1973 3. Wlsoff 60, Alntabllan A, Hartstein ML, et al: Unified diagnostic and surgical approach for unstable angina. Ann Thorac Surg 18: 472-478, 1974 4. Contl RC, Gilbert JB, Hodges M, et al: Unstable angina pectoris: randomized study of surgical versus medical therapy (abstr). Am J Cardiol 35: 129, 1975 5. Selden R, Nell WA, Rltzmann LW, et al: Medical versus surgical therapy for acute coronary insufficiency. A randomized study. N Engl J Med 293:1329-1333, 1975 8. Bertolasl EA, Tronge JE, Rlccltelll MA, et al: Natural history of unstable angina with medical or surgical therapy. Chest 70: 598-805, 1978 7. Hultgren HN, Pfelter JF, Angel1 WW, et al: Unstable angina: comparison of medical and surgical management. Am J Cardiol 39:739-740, 1977 8. Wiles X, Peduzzl PN, Hammond GL, et al: Preoperative predictors of operative mortality for coronary bypass grafting in patients with unstable angina pectoris. Am J Cardiol 39:939-943, 1977 9. Hutter AM Jr, Russell RO Jr, Resnekov L, et al: Unstable angina pectoris. National randomized study of surgical versus medical therapy: results in 1,2 and 3 vessel disease (abstr). Circulation 55, 58:Suppl lll:lii-80, 1977 10. Sheldon WC, Rlncon G, Effler DB, et al: Vein graft surgery for coronary artery disease. Survival and angiographic results in 1,000 oatients. Circulation 47. 48:Su~~i iil:ill-184-111-189. 1973 11. McNeer JF, Starmer CF, Bartei AG, et al: The nature of treatment selection in coronary artery disease. Experience with medical and surgical treatment of a chronic disease. Circulation 49:808-814, 1974 12. Stiles RR, Llndeernlth GG, Tucker BL, et al: Long-term follow-up of patients wfth coronary artery bypass grafts. Circulation 54:Suppl lll:lil-32-111-34, 1978 13. Murphy ML, Hultgren HN, Detre K, et al: Treatment of chronic stable angina: a preliminary report of survival data of randomized Veterans Administration cooperative study. N Engl J Med 297: 821-827, 1977 14. Madlgan NP, Rutherford BD, Frye RL: Clinical course and coronary anatomy of subendocardial infarction (abstr). Am J Cardioi 35: 154, 1975 15. Genovese MG, Salakl JS, Kennedy RJ, et al: Subendocardial infarction: what happens later. Chest 92~542-543, 1985 18. Madlgan NP, Rutherford BD, Frye RL: The clinical course, early prognosis and coronary anatomy of subendocardial infarction. Am J Med 80:834-841, 1978 17. Kossowsky WA, Mohr B, Rafll S, et al: Superimposition of transmural infarction following acute subendocardiai infarction. How frequent? Chest 89:758-781. 1978 18. Schelnman MM, Abbott JA: Clinical significance of transmural versus nontransmural electrocardiographic changes In patients with acute myocardial infarction. Am J Cardiol 55:802-813, 1973 19. Madlas JE, Chahlne RA, Gorlln R, et al: A comparison of transmurai and nontransmural acute myocardial infarction. Cir-
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culation 49:498-507, 1974 20. Rfgo P, Murray M, Taylor DR, ef al: Hemodynamic and prognostic findings in patients with transmural and nontransmural infarction. Circulation 51:1084-1070, 1975 21. Levy WK, Cannom DS, Cohen LS: Prognosis of subendocardiai myocardial infarction. Circulation 51:Suppi ll:li-107, 1975 22. Dussla EE, Cromartle D, McCraney J, et al: Myocardial infarction with and without laboratory documentation. One year prognosis. Am Heart J 92148-151, 1978 23. Pitt B: IV. Natural history of myocardial ischemic damage. Natural history of myocardial infarction and its prodromal syndromes. Circulation 53:Suppl l:l-132-I-140, 1978 24. Schroeder JS, Lamb IH, Harrison DC: Patients admitted to the coronary care unit for chest pain: high risk subgroup for subsequent cardiovascular death. Am J Cardiol 39:829-832, 1977 28. Judklns MP: Selective coronary arteriography. I. A percutaneous transfemoral technique. Radiology 89:815-824. 1987 Shlrey EK: Cine coronary arteriography. Mod Concepts 27. Sones 1111, Cardiovasc Dis 31:735-738. 1982 28. Alntabtlan A, Hamby RI, Garsman J: Correlation of heart size with clinical and hemodynamlc findings in patients with coronary artery disease. Am Heart J 91:21-27, 1978 28. Herman MV, Helnk RA, Klein MD, et al: Localized disorders in myocardial contraction. Asynergy and its role in congestive heart failure. N Engl J Med 277:222-232, 1987 29. Brusohke AVG: The diagnostic significance of the coronary arteriogram. A study of its value in relation to other diagnostic methods. Utrecht, Kremink en Zovn, NV, 1970 30. Simonson E: Differentiation between normal and abnormal in electrocardiography. Saint Louis, CV Mosby, 1981 31. Klein MS, Ludbrook PA, Mltnbs JW, et al: Perioperative mortality rate in patients with unstable angina selected by exclusion of myocardial infarction. J Thorac Cardiovasc Surg 73:253-257, 1977 32. Dunkman BW, Perloff JK, Kaetor JA, et al: Medical prospectives in coronary artery surgery-a caveat. Ann Intern Med 81:817-837, 1974 33. Plchard A: Coronary arteriography for everyone? Am J Cardiol 38:533-535, 1978 34. Ullyol DJ, Wlsneekl J, Sullivan RW, et al: Improved svvival after coronary artery surgery in patients with extensive coronary artery disease. J Thorac Cardiovasc Surg 70:405-413, 1975 35. Sheldon WC, Rtncon 0, Plchard AD, et al: Surgical treatment of coronary artery disease: pure graft operations with a study of 741 patients followed 3-7 years. Prog Cardiovasc Dis 18:237-253, 1975 38. Duvoldn GE, Rudy LW, Ganjl JM, et al: Direct coronary artery surgery for prolonged survival in triple vessel coronary artery disease. Circulation 51, 52:Suppl il:ll-178, 1975 37. Manley D, Frledberg HD, Auer J, et al: Late follow-up (five years) after coronary artery surgery in comparison to reported medical series (abstr.) Am J Cardlol35:155, 1975 38. Bresnahan OF, Robeits R, SheU ME, et al: Deleterious effects due to hemorrhage after myocardial reperfusion. Am J Cardlol 33: 82-88,1974 39. Madlgan NP, Rutherford BD, BemhomtDA,etal:Earlysaphemm vein grafting after subendocardial infarction: immediate surgical results and late prognosis (abstr). Circulation 53, 54:Suppl ll:ll-38, 1977
Volume 42
From the Department of Medicine, Division of Cardiology and the Department of Surgery, Cardiothoracic Dlvision, Long Island Jewish-Hillside Medical Center, New Hyde Park, Queens Hospital Center Afflliatlon, Jamaica and School of Medicine. Health Sciences Center, State university of New Yak at Stony kook, stony Brook. New York. Manuscrlpt received February 8. 1978; revised manuscript received March 1, 1978, accepted March 1.1978. Address for reprints: Atop Alntablian, MD, kpartment of Medicine, Division of Cardiology, Long Island Jewish-Hill&de Medical Center, New Hyde Park, New York 11040.
Twenty-eight patients with subendocardial infarction (Group A) were compared with 28 patients with unstable angina (Group B) and 28 with stable angina (Group C) matched for age and sex. The three groups did not dtffer in prevalence of diabetes, hypertension, old infarction or duration of disease. There were no significant differences in number of diseased vessels, coronary score, abnormal left ventricular wall motion or left ventricular end-diastolic pressure. Angiograms performed 2 weeks postoperatively revealed closure of 3 of 31 grafts (18 patients) in Group A, closure of 3 of 34 grafts (17 patients) in Group B and closure of 8 of 50 grafts (22 patients) in Group C (differences not significant). Postoperative angiograms showed improved wall motion in 37 percent of Group A, 53 percent of Group B and 38 percent of Group C (dtfferences not significant). Postoperative new 0 waves appeared in one patient in Group A and in two patients in Groups B and C. There were no hospital or late deaths. In a mean follow-up period of 29 months, 88 percent of patients in Group A, 81 percent in Group B and 54 percent in Group C were asymptomatic. Thus, bypass grafting was performed with similarly low mortality and morbidity in patients with subendocardial infarction and in those with angina; more than one third of postoperative angiograms in the three groups showed improved wall motion; and late follow-up studies demonstrated functional improvement in the majority of patients in all three groups.
The course of coronary artery disease is unpredictable in any individual patient with angina pectoris. However, in recent years, studies’-5 have shown that in some patients “stable” angina passes through the stages of “unstable,” “progressive” or “preinfarction” angina before a transmural or subendocardial infarction develops. After the initial controversies concerning prognosis in surgically treated patients with unstable angina,l-5 several studies~s indicated not only symptomatic improvement but also longer survival after bypass surgery. However, Hutter et al.9 found that such patients had a greater incidence of new Q waves than medically treated patients and no improvement in survival. There is disagreement lels whether bypass surgery, in addition to alleviating symptoms, prolongs survival in patients with stable angina. Among patients with subendocardial infarction, those treated medically have shown a 10 to 37 percent rate of transmural infarction1p17 and a 0 to 18 percent mortality rate within 4 weeks1s20 and a 3 to 14 percent yearly mortality rate after hospital discharge.2@~2c~21Similarly, both a high yearly rate of transmural myocardial infarction and a high mortality rate have been found in patients who are admitted to a coronary care unit with symptoms of myocardial infarction but whose electrocardiogram did not confirm the diagnosis.22-24 In this report we present our experience with coronary bypass surgery in 28 patients with subendocardial infarction and in an equal number of patients with unstable and stable angina pectoris who were followed up postoperatively for a mean period of 29 months. Material
and Methods
Patients
Among 800 patients undergoing saphenous vein bypass graft surgery between January 1972 and July 1977 at this institution, 28 had preoperative subendocardial infarction. These patients (Group A) were compared with 28 patients
August 1978
The American Journal of CARDIOLOGY
Volume 42
183
BYPASS
GRAFTING FOR SUBENDOCARDIAL
INFARCTION-AINTABLIAN
ET AL.
with unstable angina pectoris (Group B) and 28 patients with stable (Group C) angina pectoris who were matched for age and sex. Almost all patients in the group with subendocardial infarction were admitted to the hospital from the emergency room with a history of chest pain lasting more than 30 minutes and findings of symmetric T wave inversion with or without S-T segment depression. They were observed in the coronary care unit to rule out transmural infarction. A few patients with similar continuous angina were transferred from the coronary care unit of other hospitals because of electrocardiographic evidence of subendocardial infarction and significant enzyme elevations. After 24 to 48 hours of observation in our hospital, if transmural infarction did not develop, coronary angiography was performed. The criteria for subendocardial infarction included (1) angina pectoris at rest lasting more than 15 minutes; (2) elevation of at least two of three serum enzymes (creatine kinase, serum glutamic oxaloacetic transaminase or lactic dehydrogenase) to at least twice normal values or greater; (3) T wave inversion or S-T segment depression, or both, lasting more than 48 hours without pathologic & waves. The criteria for unstable angina were those previously reported.3 The group with stable angina met New York Heart Associationz5 criteria for class II to IV angina pectoris without acute electrocardiographic changes and symptoms relieved with rest or sublingual nitroglycerin. Most of these patients had progressive angina. Patients were excluded if they were undergoing left ventricular aneurysmectomy, prosthetic valve replacement or repair of associated congenital heart defect in addition to bypass grafting or if they had bundle branch block. Studies Hemodynamic studies were performed after an overnight fast, after all medications except nitroglycerin and long-acting nitrates had been discontinued for at least 24 hours. Left and right heart catheterization and left ventricular and selective coronary angiography, using the Judkins2s or
Sones and Shireyz7 techniques, were performed in all patients. In quantitating left ventricular dysfunction and the patterns of left ventricular contraction, we used the techniques and principles previously reported,28 utilizing the descriptive terminology suggested by Herman et al.sg The severity and extent of coronary disease were graded according to the criteria of Bruschke et al.sO All angiograms and electrocardiograms were reviewed by two cardiologists and accepted for study only if there was complete agreement on interpretation. Twelve lead electrocardiograms were performed in each patient on admission and on the day before cardiac catheterization. In addition, patients with subendocardial infarction or unstable angina had electrocardiograms performed daily and also immediately after cardiac catheterization to rule out the occurrence of trmmural infarction during the procedure. This precaution was taken because several of the patients with subendocardial infarction had additional anginal attacks after ventriculography or coronary angiography. A normal resting electrocardiogram was defined with conventional critaria.31 Coronary revascularization tion of cardiac catheterization
was performed
after comple-
in all patients with subendocardial infarction and unstable angina with significant coronary obstruction. The patients were transferred directly from the catheterization laboratory to the operating room. Repeat left heart catheterization and selective graft angiography were performed 2 to 3 weeks after surgery in all patients giving consent.
184
August 1978
The American Journal d CARDIOLOGY
TABLE I Clinical Profile
Infarction no. % ii?@% Patients’
iiF@%
28
100
28
100
28
100
23
82
23
86
23
82 18
z 8
:; 29
1: 11
:: 39
1; 8
t:
:
29 11
8 3
29 11
8 6
29 21
54 25 21
11 11 6
39 39 21
9 9 10
32 32 36
Sex
Male
Female History of infarction Evidence of infarction In electrocardiogram History of hypertension History of diabetes Angina pectoris 5 years
15 ;
l In all three groups, the patients had a mean age (k standard deviation) of 53 f 8 years (range 34 to 72 years).
Results Of 800 patients with coronary artery disease who underwent saphenous vein bypass surgery, 28 had subendocardial infarction (Group A). These patients were compared with 28 patients with unstable (Group B) and 28 with stable (Group C) angina. Age, sex, prevalence of diabetes mellitus, hypertension, old myocardial infarction or duration of disease did not differ among the three groups (Table I). No significant differences in the number of diseased vessels, coronary score, abnormal left ventricular wall motion, elevated pulmonary wedge or left ventricular end-diastolic pressures were found in these three groups (Table II). Angiograms obtained 2 weeks after operation revealed closure of 3 of 31 grafts (10 percent) in 16 patients in Group A, closure of 3 of 34 grafts (9 percent) in 17 patients in Group B, and closure of 6 of 55 grafts (11 percent) in 22 patients in Group C (differences not significant). The postoperative study revealed improved left ventricular wall motion in 6 patients (37 percent) in Group A, 9 patients (53 percent) in Group B and 8 patients (36 percent) in Group C (differences not significant). Wall motion was unchanged in 8 patients (50 percent) in Group A, in 6 (35 percent) in Group B and 13 (59 percent) in Group C. Only 2 patients (13 percent) in Group A, 2 (12 percent) in Group B and l(4 percent) in Group C manifested postoperative deterioration of the left ventricular segmental wall motion. New Q waves appeared perioperatively in one patient in Group A and in two patients each in Groups B and C (difference not significant). One patient in Group B had a postoperative cerebrovascular accident with left-sided hemiplegia. Three patients each in Group B and C and one in Group A had postoperative pulmonary emboli that responded to systemic anticoagulation. A postpericardiotomy syndrome occurred in one patient each in Groups A and C, requiring steroid therapy in one.
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TABLE II Anglographic Data Group A: Subendocardial Infarction no. %
Patients Coronary artery disease Single Double Triple RCA LAD LCX LCA Abnormal LV angiogram (preop) Elevated pulmonary wedge pressure I12mmHg Elevated left ventricular enddiastolic pressure 5 12mmHa
Group 8: Unstable ,$ngintO
Zr!fF n&rgin;O
28
100
28
100
28
100
10 8
3 15 IO 16 27 20 4 21
11 54 36 57 96 71 14 75
6
21
2:
36 29 36 61 93 46 14 75
1: 19 26 20 0 16
:9” 68 93 71 0 57
2
7
2
7
3
11
14
50
11
39
11
39
l
:; 26 13
Patients in Groups A, B and C had a coronary score (mean f standard deviation) of 9 f 3, 10 f 3 and 10 f 3, respectively. LAD = left anterior descending coronary artery: LCA = left main coronary artery; LCx = left circumflex artery; LV = left ventricular; preop = preoperative; RCA = right coronary artery. l
There were no hospital or late deaths. During a mean follow-up period of 29 months (range 5 to 64), a transmural infarction developed in one patient in Group B. One patient in Group A and two in Group C underwent reoperation because of recurrence of angina pectoris at rest. At the end of the follow-up period, 68 percent of patients in Group A were in New York Heart Assocation class I and 29 percent in class II-III. In Group B, 61 percent were in class I and 36 percent in class II-III. In Group C, 54 percent were in class I and 43 percent in class II-III. Discussion Natural history of subendocardial infarction: The hospital course and subsequent follow-up of patients with nontransmural (subendocardial) infarction have shown that this entity is treacherous, with a significant incidence of transmural infarction and death.3p4*32Indeed, several studies1g-21 have indicated that the natural history of subendocardial infarction does not differ significantly from that of classic transmural infarction. Madigan et al.ls showed, in a mean follow-up period of 11 months, that of 50 patients with subendocardial infarction 46 percent had unstable angina and only 24 percent were asymptomatic with medical therapy. In 6 of 28 patients (21 percent) receiving medical therapy a transmural infarction developed, and 1 patient (3 percent) died. Levy and associates21 noted, in a mean follow-up period of 35 months, that sudden death and recurrent infarction occurred twice as often in patients with a nontransmural infarction as in those with a transmural infarction. Other&24 have reported that patients with prolonged
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ET AL.
ischemic chest pain, but without evidence of transmural infarction, had a yearly mortality rate of 10 to 13 percent. Bypass surgery in unstable and stable angina: Recent comparisons of the incidence of myocardial infarction and long-term mortality in patients with unstable angina receiving medical therapy and in similar patients undergoing bypass surgery revealed a lower yearly mortality in the surgical group as well as greater symptomatic improvement.e,7 Whether patients with unstable angina have greater perioperative mortality is controversial.3TsJJ Surgical mortality in patients with unstable angina depends on selection and surgical expertise and thus varies greatly from institution to institution.3,32*33 The beneficial results of coronary bypass surgery in patients with stable angina remains controversial. Several reports indicated not only better symptomatic improvement in the surgical treatment group with multivessel coronary disease but also a lower yearly mortality after 2 to 7 year follow-up, when compared with nonrandomized medical treatment groups_10,11,34-38H owever, the randomized Veterans Administration Cooperative Study, after a 3 year follow-up of 310 medically treated patients and 285 with coronary bypass showed no prolongation of life in the surgical group, an operative mortality rate of 5.6 percent and a yearly mortality rate of 4 percent.13 Bypass surgery in subendocardial infarction: Our results in 28 patients indicate that coronary bypass surgery can be performed in patients with subendocardial infarction. The mortality and perioperative morbidity of this group are not different from those of patients with unstable or stable angina, and the majority of patients are asymptomatic after surgery. Bypass grafting is not recommended in acute transmural infarction because of definitely increased mortality as well as experimental evidence that reperfusion of acute infarcts leads to larger zone hemorrhage and necrosis.38 The absence of mortality in our 28 surgically treated patients with subendocardial infarction and their generally benign postoperative course differ significantly from the reported surgical experience in patients with classic transmural infarction. Clearly, the areas of infarction, although sufficient to produce diagnostic enzyme and electrocardiographic abnormalities, were not so extensive or confluent as to result in significant infarct extension after bypass surgery. The incidence rate of perioperative Q waves did not differ significantly in the group with subendocardial infarction and those with unstable or stable angina (4 versus 7 percent), suggesting that the areas of actual infarction were small. Larger areas might be expected to extend postoperatively sufficient to present as postoperative Q waves. Madigan et a1.3g reported a similar experience with surgically treated patients with subendocardial infarction. Among their 28 patients, perioperative new Q waves developed in 10.7 percent, and one patient (3.6 percent) died. In a mean follow-up period of 16 months,
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78 percent were free of angina pectoris and there were no late deaths or infarctions. Perhaps the most significant observation regarding the efficacy of bypass grafting in our group with subendocardial infarction is the improved ventricular contractile pattern in 37 percent of patients, an incidence rate identical with that of the group with stable angina. None of our patients had technetium pyrophosphate
scans before or after bypass surgery. Therefore, we do not know whether such scans would have shown any difference between the group with subendocardial infarction and that with stable angina. If the results in this small series are extended and confirmed, coronary bypass grafting could be considered an effective method for preserving ischemic myocardium, relieving symptoms and prolonging life in patients with subendocardial infarction.
References 1. Gazes PC, Mobley EW Jr, Farls HW Jr, et al: Preinfarction (unstable) angina-a prospective study-ten year follow-up. Prognostic significance of electrocardiographic changes. Circulation 48~331-337, 1973 2. Fish1 SJ, Herman MV, Gorlln R: The intermediate coronary syndrome: clinical, angiographic and therapeutic aspects. N Engl J Med 288:1193-1198, 1973 3. Wlsoff 60, Alntabllan A, Hartstein ML, et al: Unified diagnostic and surgical approach for unstable angina. Ann Thorac Surg 18: 472-478, 1974 4. Contl RC, Gilbert JB, Hodges M, et al: Unstable angina pectoris: randomized study of surgical versus medical therapy (abstr). Am J Cardiol 35: 129, 1975 5. Selden R, Nell WA, Rltzmann LW, et al: Medical versus surgical therapy for acute coronary insufficiency. A randomized study. N Engl J Med 293:1329-1333, 1975 8. Bertolasl EA, Tronge JE, Rlccltelll MA, et al: Natural history of unstable angina with medical or surgical therapy. Chest 70: 598-805, 1978 7. Hultgren HN, Pfelter JF, Angel1 WW, et al: Unstable angina: comparison of medical and surgical management. Am J Cardiol 39:739-740, 1977 8. Wiles X, Peduzzl PN, Hammond GL, et al: Preoperative predictors of operative mortality for coronary bypass grafting in patients with unstable angina pectoris. Am J Cardiol 39:939-943, 1977 9. Hutter AM Jr, Russell RO Jr, Resnekov L, et al: Unstable angina pectoris. National randomized study of surgical versus medical therapy: results in 1,2 and 3 vessel disease (abstr). Circulation 55, 58:Suppl lll:lii-80, 1977 10. Sheldon WC, Rlncon G, Effler DB, et al: Vein graft surgery for coronary artery disease. Survival and angiographic results in 1,000 oatients. Circulation 47. 48:Su~~i iil:ill-184-111-189. 1973 11. McNeer JF, Starmer CF, Bartei AG, et al: The nature of treatment selection in coronary artery disease. Experience with medical and surgical treatment of a chronic disease. Circulation 49:808-814, 1974 12. Stiles RR, Llndeernlth GG, Tucker BL, et al: Long-term follow-up of patients wfth coronary artery bypass grafts. Circulation 54:Suppl lll:lil-32-111-34, 1978 13. Murphy ML, Hultgren HN, Detre K, et al: Treatment of chronic stable angina: a preliminary report of survival data of randomized Veterans Administration cooperative study. N Engl J Med 297: 821-827, 1977 14. Madlgan NP, Rutherford BD, Frye RL: Clinical course and coronary anatomy of subendocardial infarction (abstr). Am J Cardioi 35: 154, 1975 15. Genovese MG, Salakl JS, Kennedy RJ, et al: Subendocardial infarction: what happens later. Chest 92~542-543, 1985 18. Madlgan NP, Rutherford BD, Frye RL: The clinical course, early prognosis and coronary anatomy of subendocardial infarction. Am J Med 80:834-841, 1978 17. Kossowsky WA, Mohr B, Rafll S, et al: Superimposition of transmural infarction following acute subendocardiai infarction. How frequent? Chest 89:758-781. 1978 18. Schelnman MM, Abbott JA: Clinical significance of transmural versus nontransmural electrocardiographic changes In patients with acute myocardial infarction. Am J Cardiol 55:802-813, 1973 19. Madlas JE, Chahlne RA, Gorlln R, et al: A comparison of transmurai and nontransmural acute myocardial infarction. Cir-
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culation 49:498-507, 1974 20. Rfgo P, Murray M, Taylor DR, ef al: Hemodynamic and prognostic findings in patients with transmural and nontransmural infarction. Circulation 51:1084-1070, 1975 21. Levy WK, Cannom DS, Cohen LS: Prognosis of subendocardiai myocardial infarction. Circulation 51:Suppi ll:li-107, 1975 22. Dussla EE, Cromartle D, McCraney J, et al: Myocardial infarction with and without laboratory documentation. One year prognosis. Am Heart J 92148-151, 1978 23. Pitt B: IV. Natural history of myocardial ischemic damage. Natural history of myocardial infarction and its prodromal syndromes. Circulation 53:Suppl l:l-132-I-140, 1978 24. Schroeder JS, Lamb IH, Harrison DC: Patients admitted to the coronary care unit for chest pain: high risk subgroup for subsequent cardiovascular death. Am J Cardiol 39:829-832, 1977 28. Judklns MP: Selective coronary arteriography. I. A percutaneous transfemoral technique. Radiology 89:815-824. 1987 Shlrey EK: Cine coronary arteriography. Mod Concepts 27. Sones 1111, Cardiovasc Dis 31:735-738. 1982 28. Alntabtlan A, Hamby RI, Garsman J: Correlation of heart size with clinical and hemodynamlc findings in patients with coronary artery disease. Am Heart J 91:21-27, 1978 28. Herman MV, Helnk RA, Klein MD, et al: Localized disorders in myocardial contraction. Asynergy and its role in congestive heart failure. N Engl J Med 277:222-232, 1987 29. Brusohke AVG: The diagnostic significance of the coronary arteriogram. A study of its value in relation to other diagnostic methods. Utrecht, Kremink en Zovn, NV, 1970 30. Simonson E: Differentiation between normal and abnormal in electrocardiography. Saint Louis, CV Mosby, 1981 31. Klein MS, Ludbrook PA, Mltnbs JW, et al: Perioperative mortality rate in patients with unstable angina selected by exclusion of myocardial infarction. J Thorac Cardiovasc Surg 73:253-257, 1977 32. Dunkman BW, Perloff JK, Kaetor JA, et al: Medical prospectives in coronary artery surgery-a caveat. Ann Intern Med 81:817-837, 1974 33. Plchard A: Coronary arteriography for everyone? Am J Cardiol 38:533-535, 1978 34. Ullyol DJ, Wlsneekl J, Sullivan RW, et al: Improved svvival after coronary artery surgery in patients with extensive coronary artery disease. J Thorac Cardiovasc Surg 70:405-413, 1975 35. Sheldon WC, Rtncon 0, Plchard AD, et al: Surgical treatment of coronary artery disease: pure graft operations with a study of 741 patients followed 3-7 years. Prog Cardiovasc Dis 18:237-253, 1975 38. Duvoldn GE, Rudy LW, Ganjl JM, et al: Direct coronary artery surgery for prolonged survival in triple vessel coronary artery disease. Circulation 51, 52:Suppl il:ll-178, 1975 37. Manley D, Frledberg HD, Auer J, et al: Late follow-up (five years) after coronary artery surgery in comparison to reported medical series (abstr.) Am J Cardlol35:155, 1975 38. Bresnahan OF, Robeits R, SheU ME, et al: Deleterious effects due to hemorrhage after myocardial reperfusion. Am J Cardlol 33: 82-88,1974 39. Madlgan NP, Rutherford BD, BemhomtDA,etal:Earlysaphemm vein grafting after subendocardial infarction: immediate surgical results and late prognosis (abstr). Circulation 53, 54:Suppl ll:ll-38, 1977
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