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Surgical versus medical treatment of coronary artery disease
Surgical versus Medical Treatment of Coronary Artery Disease Nine Year Follow-Up of 9,061 Patients
Don C. Wukasch, MD, Houston, Texas Denton A. Cooley, MD, Houston, Texas Robert J. Hall, MD, Houston, Texas George J. Reul, Jr, MD, Houston, Texas Frank M. Sandiford, MD, Houston, Texas Sherri L. Zillgitt, BS, Houston, Texas
Direct reconstruction of congenital coronary artery anomalies by aortocoronary bypass was first performed in our hospital in 1963 [I], and long-term follow-up has demonstrated late patency of these grafts [2]. Subsequent application of this technic using autogenous saphenous vein grafts for acquired atheromatous coronary artery occlusive disease [3,4] has been proven successful in relief of angina pectoris in the majority of patients [5,6]. Long-term follow-up has suggested increased life expectancy in patients treated surgically [7] compared with those treated medically in the series of Bruschke, Proudfit, and Sones 181. Recent reports, however, advocating the efficacy of medical management of coronary artery occlusive disease, notably the Veterans’ Administration Randomized Cooperative Study [9], have created considerable controversy within the medical profession and confusion among patients. From these data, Braunwald [IO] suggested that surgical treatment of coronary artery occlusive disease does not prolong life expectancy. To ascertain whether surgical therapy does increase life expectancy in patients with coronary artery occlusive disease, all patients undergoing aortocoronary bypass surgery in our institution during the past nine years have been reviewed and the survival rates compared with those of the medically treated patients in the Veterans’ Administration Randomized Cooperative Study [9].
From the Divisions of Surgery and Cardiology, Texas Heart Institute of St. Luke’s Episcopal and Texas Chifdran’s Hospitals, and Ths Universityof Texas Health Science Center, Houston, Texas. Reprint requests should be addressed to Don C. Wukasch, MD, Texas Heart Institute, PO Box 20345. Houston, Texas 77025. Presented at the Thirtieth Annual Meeting of the Southwestern Surgical Congress, Palm Springs, California, April 17-20, 1978.
Volume 137, February 1979
Material and Methods Selection of Patients
All patients considered for myocardial revascularization were evaluated with stress electrocardiography and selective cineangiography, with complete mapping of the coronary arteries. The primary indication for operation was the presence of angina pectoris which interfered with the patient’s quality of life or work. Patients with unstable angina were not excluded from this study, and 17 per cent of patients exhibited unstable angina. A second group of patients in whom operation was performed were asymptomatic patients with ischemia on treadmill exercise testing and with angiographically demonstrated significant lesions in one or more major vessels, particularly the left main coronary artery. Approximately 8 per cent of patients in this series had significant stenotic lesions in the left main coronary artery. Although 75 per cent reduction in lumen diameter has frequently been considered to be the definition of a “significant” stenotic lesion, impedance of blood flow by an arteriosclerotic plaque depends not only upon the degree of lumen area occlusion produced, but also on the length of the obstruction [II]. Thus, a 50 per cent lumen area stenotic lesion 6 mm in length may produce the same reduction in blood flow as a 90 per cent lumen area lesion 1 mm in length. We believe that all lesions producing approximately 50 per cent stenosis should be bypassed at the time of aortocoronary bypass, because in our experience, nonbypassed 50 per cent lesions are one of the major factors in patients requiring reoperation after aortocoronary bypass due to progression of disease [121. Durmg the early period of our experience, severe left ventricular decompensation, with elevated end-diastolic pressure and reduced ejection fraction, was considered to be a contraindication for operation. Poor left ventricular function when accompanied by angina, however, is no longer considered to be a contraindication for aortocoronary bypass, unless there is angiographic evidence of diffuse disease in the distal vessels which would preclude
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TABLE I
All Cases of Coronary Bypass Surgery (July 1966 through June 30,1977) Procedure
No. of Patients
Coronary bypass only Left ventricular aneurysm resection Aortic valve procedure Mitral valve procedure Other associated procedures
9,061 683 384 281 243
Total
10.652
bypass. In the present series, the ejection fraction was reduced to less than 0.60 in 48 per cent of patients and to less than 0.45 in 18 per cent of patients. The indication for aortocoronary bypass in patients without angina but with symptomatic left ventricular dysfunction remains controversial. Our present impression is that patients with no angina and symptoms of congestive heart failure secondary to generalized left ventricular dysfunction, as opposed to those with the treatable complications of myocardial infarction, such as ventricular aneurysm, ventricular septal defect, or mitral valve incompetence, will benefit little from revascularization. We believe that preinfarction angina constitutes another indication for emergency aortocoronary bypass. Patients with uncontrollable ventricular arrhythmias associated with myocardial ischemia may also benefit from emergency revascularization. Patients experiencing uncontrollable cardiogenic shock after acute myocardial infarction can be frequently salvaged by intraaortic counterpulsation balloon pumping followed by emergency coronary arteriography and revascularization. satisfactory
Surgical Technic
The technics used in our revascularization procedures have been described in previous publications [13,14]. Most operations for myocardial revascularization were performed utilizing ischemic cardiac arrest under temporary cardiopulmonary bypass with hemodilution technics. When a localized stenosis of the right coronary artery was the only lesion present, bypass was performed without cardiopulmonary bypass. Since January 1977, cardioplegic solution at 5’C consisting of 500 cc of 5 per cent dextrose and 0.45 per cent sodium chloride, containing potassium chloride 15 mM, magnesium chloride 7.5 mM, sodium bicarbonate 2.5 mM, and calcium chloride 1.0 mM, has been injected into the ascending aorta after cross clamping. After cardiopulmonary bypass was begun by conventional technic, the heart was arrested and cooled topically. Distal anastomoses were performed with 6-O monofilament polypropylene continuous suture. Proximal anastomoses were performed with 5-O continuous suture after the aortic cross clamp was released and a partial occlusion clamp applied, permitting cardiopulmonary bypass to continue and restoring coronary perfusion. Optical magnification and fiberoptic lighting provided precision in anastomosing small arteries.
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Figure 1. Age and sex disfributton of patients undergoing aortocoronary bypass.
To decompress the arrested heart and provide a bloodless field for coronary anastomoses after the ascending aorta was cross clamped, a special aspirating needle was inserted into the ascending aorta and suction through a roller pump was applied, returning the aspirated blood to the extracorporeal circuit. This method prevents air from entering the cardiac chambers and eliminates the concern for air embolism. The technic of using sequential grafts (1 vein anastomosed side to side to 2 arteries or more) has enhanced the surgeon’s ability to revascularize all significant lesions. This technic is particularly applicable for multiple lesions in adjacent arteries and in patients having a limited length of available vein or a short ascending aorta which would make placement of five or six proximal anastomoses technically difficult. Endarterectomy is avoided when possible but is sometimes necessary in the occluded right coronary artery [5]. The saphenous vein is carefully removed and all branches are ligated in a manner that does not compromise the main lumen. Distension of the vein is accomplished with heparinized blood, since the vein wall may be injured when a saline solution is used. When the patient does not have saphenous veins that are suitable for the bypass, the alternative source of grafts is veins in the arm. The cephalic veins are more difficult to use because of lack of smooth muscle layers, but long-term results have been satisfactory. Internal mammary arteries have seldom been used in this institution and were reserved primarily for patients in whom no other vessel was available. Vascular substitutes were used in a few patients who had no other vessel availabIe, but the results were not promising. The need for a synthetic or biologic tissue substitute for the saphenous vein remains obvious. Clinical Material
Between July 1,1968 and June 30,1977, a consecutive series of 10,652 patients underwent aortocoronary artery bypass at the Texas Heart Institute. No patients were excluded from the series regardless of risk factors or severity
The American Journal of Surgery
Treatment of Coronary Artery Disease
15
1
Figure 3. Early moriaMy by year of study demonstrathg decline in mortalfty.
formed, early mortality for all patients undergoing aortocoronary bypass alone was 9.1 per cent (16 deaths among 175 patients). During 1977, early mortality in patients undergoing aortocoronary bypass alone declined to 1.7 per cent (26 deaths among 1,517 patients). (Figure 3;) Early Mortality Related to Sex. It has been apparent from the beginning of our experience that female patients with coronary artery disease represented a significantly higher risk of early death, as demonstrated in Table II, which reveals an early mortality of 6.6 per cent in female patients compared to 3.0 per cent in male patients during the entire series. During the most recent period of the study between January 1,1977 through June 30,1977, early mortality in male patients was reduced to 1.2 per cent but in female patients to only 4.6 per cent. (Table II.)
Figure 2. Distribution of patients by number of grafts performed.
of disease. Among these, 9,061 patients underwent aortocoronary bypass alone, and the remaining 1,591 underwent concomitant surgical procedures associated with cardiovascular dysfunction as shown in Table I. Among the 9,061 patients who underwent aortocoronary bypass alone, 86.6 per cent were males and 13.4 per cent females. The mean age of all patients was 54.1 years. (Figure 1.) The majority of patients were in the forty to sixty-nine year age group, although 433 patients were less than forty years old and 306 were more than seventy years old. As increased surgical experience has been acquired, an attempt has been made to bypass every stenotic coro-
nary artery which would permit a satisfactory anastomosis. In the entire series, 56.8 per cent of patients underwent three or more bypass graft procedures.
Late Mortality Related to Sex and Number of Grafts Required. Although early mortality was sig-
(Figure 2.)
nificantly higher in females than in males, the late mortality in males and females was similar: 2.9 per cent and 2.5 per cent, respectively. (Table III.) In both male and female patients, late mortality appeared to be lower in those patients in whom more complete revascularization was performed. (Table III.)
Results
Percentage of Early Mortality by Year. Early mortality (hospital death) has declined each year during the study, apparently the result of increasing technical experience. During 1970, the first year in which significant numbers of operations were per-
TABLE II
Early Mortality Related to Sex for Coronary Bypass Surgery Only July 1968 Through June 30, 1977 No. of No. of Patients Deaths Mot&y
January 1. 1977 Through June 30, 1977 No. of No. of Patients Deaths Mortality
Males Females
7,843 1,218
234 80
3.0% 6.6 %
1,298 219
16 10
1.2% 4.6%
Total
9,061
314
3.5 %
1,517
26
1.7%
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TABLE III
Late Mortality Related to Sex and Number of Grafts Required (June 1966 through June 30, 1977)’ Males No. of Deaths
Single vessel Double vessel Triple vessel Four vessels or more Total
Procedure
l
Total
Females Mortality
No. of Deaths
Mortality
6 13 8 1
2.8% 3.3% 1.9% 0.9%
32 126 82 8
3.5% 4.4% 2.2% 0.7%
28
2.5%
248
2.8%
Mortality
No. of Deaths
26 113 74 7
3.7% 4.6% 2.2% 0.7%
220
2.9%
From a total patient population of 9,061.
Causes of Death. Among 314 early deaths, the most common causes of death in both males and females were intraoperative or postoperative myocardial infarction, cerebrovascular accident, arrhythmia, and congestive heart failure. (Table IV.) The causes of late deaths were myocardial infarction, cerebrovascular accident, and congestive heart failure. (Table V.) Therefore, only approximately 50 per cent of late deaths were cardiac related. Long-Term Symptomatic Results. Analysis of symptomatic results among 4,928 patients in whom accurate follow-up information could be obtained demonstrated that male patients experienced slightly better symptomatic results than female patients. Ninety-two per cent of male patients remained either asymptomatic or significantly improved throughout the follow-up period, whereas 89 per cent of females remained in this category. (Table VI.) Comparison of long-term symptomatic results by number of vessels bypassed demonstrated consistent improvement in long-term symptomatic results as more vessels were bypassed. (Table VII.) Long-Term Suruiual. Actuarial surgical survival curves calculated by the life table method (Cutler) [15] to nine years demonstrated an annual attrition rate of 2.38 per cent. Three years after surgery 92 per cent were alive, and at nine years 79.6 per cent of patients were alive. (Figure 4.)
Comments
The reduction in early mortality from 9.1 to 1.7 per cent during the period of this study is encouraging and emphasizes the importance of increased surgical experience and improved technics. These include the use of cold cardioplegia, topical cardiac hypothermia, and greater technical precision provided by optical magnification and high intensity illumination. Improved early mortalities have resulted even though our indications for aortocoronary bypass have been broadened to include those patients who have angina pectoris in the presence of poor ventricular function (ejection fractions less than 0.2). As a rule, among patients with disabling angina pectoris, only those who have angiographic evidence of diffuse coronary arteriosclerosis which would preclude technically satisfactory grafts are refused operation [16]. When higher risk patients were excluded from the series, early mortality was approximately 1 per cent, a rate considered acceptable for most elective major surgical procedures. For example, in a recent consecutive series of patients from Holland, which excluded acute emergency cases, 268 underwent coronary bypass procedures with one death (0.4 per cent mortality) 1141.
TABLE V TABLE IV
Causes of Early Death After Coronary Bypass Surgery Only (July 1966 through June 1977)
Causes of Late Death After Coronary Bypass Surgery Alone (July 1966 through June 1977) No. of Patients
Cause of Death Cause of Death
l
204
No. of Patients*
Myocardial infarction Cerebrovascular accident Arrhythmia Congestive heart failure Hemorrhage Unknown Miscellaneous
128 56 49 35 6 18 22
Total
314 (100.0%)
From a patient population of 9,061.
Myocardial infarction Cerebrovascular accident Congestive heart failure Malignancy Arrhythmia Hemorrhage Thrombus Miscellaneous Unknown
(40.8%) (17.8%) (15.6%) (11.2%) (1.9%) (5.7%) (7.0%)
61 29 26 22 10 8 7 31 54
248 (100.0%)
Total l
(24.6%) (11.7%) (10.5%) (8.9%) (4.0%) (3.2%) (2.8%) (12.5%) (21.8%)
From a patient population of 9,061.
The American Journal of Surgery
Treatment of Coronary Artery Disease
TABLE VI
The higher early mortality in females compared with males is striking. Particularly notable is the fact that early mortality has been reduced considerably more in male than in female patients [ 71. A possible explanation for this difference may be that when coronary insufficiency develops in women, the metabolic derangement is more severe, thereby producing more diffuse lesions. Moreover, it has been our impression that the coronary arteries in women tend to be smaller, more friable, and more frequently intramyocardial in location than in men, thereby making satisfactory anastomoses technically more difficult. Curiously, for reasons that are not apparent, the higher risk of early mortality in females did not extend to late mortality, which was approximately the same for men and women. Once the female patient has survived operation, patency rates of the grafts in women are the same as in men. Support of the concept that a more severe metabolic derangement exists in women who develop coronary artery occlusive disease is suggested by the high surgical mortality in younger patients (aged 40 to 49 years). Most women in this age group are premenopausal and should have been protected somewhat from developing coronary artery occlusive disease. Apparently the arteriosclerotic process superseded the possible hormonal protection. Another factor to be considered is the higher incidence of diabetes among women. The importance of complete revascularization of ail stenotic coronary arteries is demonstrated by lower late mortality in those patients in whom more complete revascularization was achieved. In our opinion, the improved long-term survival outweighs the slightly higher early mortality associated with the more prolonged surgical procedure required for multiple bypass grafts. Additionally, our experience has revealed that complete revascularization of all lesions producing more than 50 per cent luminal stenosis is a major factor in reducing the need for subsequent “redo” revascularization procedures [12]. Moreover, the results clearly indicate better long-
TABLE VII
Patient Percentage* Males Females Total
Symptoms Asymptomatic or improved Symptoms unchanged Symptoms worse Unknown Total
92.0 4.0 2.0 2.0
89.0 5.0 4.0 2.0
91.0 4.0 3.0 2.0
100.0
100.0
100.0
From a patient population of 4,928 from whom follow-up data were obtained. l
term symptomatic relief with more complete revascularization. A recently published Veterans’ Administration Cooperative Study [9] of randomized patients with stable angina pectoris, one group receiving medical and the other surgical treatment, questions the efficacy of coronary artery revascularization in prolonging life [IO]. That study reported that 87 per cent of medically treated patients were alive compared to 88 per cent treated surgically three years after diagnosis. This cooperative study, however, has certain features that raise concern regarding the validity of their conclusions. First, the number of surgical patients from each of the cooperating hospitals was small and averaged less than ten patients per hospital per year. The Veterans’ Administration Study, thus, did not take into consideration the influence of surgical experience on operative mortality. The Veterans’ Administration Cooperative Study considered the period 1972 through 1974, during which time the operative mortality was 5.6 per cent, which is similar to our own early mortality of 4.4 per cent during this period. Use of this figure as anticipated early mortality for aortocoronary bypass, however, does not appear valid in view of current early mortality of 1.7 per cent in our own institution and similar figures from other large centers with greater surgical experience than
Long-Term Symptomatic Results for Patients Undergoing Coronary Bypass Surgery Only according to Number of Grafts
Symptoms Asymptomatic or improved Symptoms unchanged Symptoms worse Unknown Total l
Long-Term Symptomatic Results according to Sex for Coronary Bypass Surgery Only (July 1966 through June 30, 1977)
Single Vessel
Double Vessel
Percentage Incidence’ Triple 4 Grafts or Vessel More
Total
86 8 4 2
90 5 3 2
93 3 2 2
95 3 1 1
91 4 3 2
100
100
100
100
100
From a total patient population of 4,928.
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Wukasch et al
actuarial survival of the medically treated patients
@I-
I
2
3
4 5 SURVIVAL
6 7 TIME-YEARS
9
9
F/g~re 4. Actuarial curve comparin9 survival of entire Texas Heart lnstttute surgical series and Veterans’ AdmMstratton Cooperative Study medical series. ‘from [9]; l ‘from [8].
reported from the cooperating Veterans’ Administration hospitals. A second major weakness of the Veterans’ Administration Cooperative Study is that patients with major risk factors were not included. These factors are (1) unstable angina, (2) left main coronary artery lesions, and (3) being female. In contrast, our surgical series includes all patients, including 17 per cent with unstable angina, 8 per cent with left main coronary artery lesions, and 13.4 per cent female patients. In all other major areas of comparison, the patient populations of our study and the Veterans’ Administration Cooperative Study were similar. A third striking weakness of the Veterans’ Administration Cooperative Study is the bias in favor of the medically treated patients which appears to be introduced by exclusion before randomization of certain patients at physician or patient preference. Approximately 25 per cent of the Veterans’ Administration Cooperative Study patients .eligible for randomization were excluded because of death (8 per cent), unwillingness to enter the study (38 per cent), or “other” unspecified reasons (48 per cent) [17]. This exclusion of significant numbers of patients from randomization allows the possibility of patients exhibiting more severe disease having been diverted to nonrandomized surgical treatment. A fourth major weakness of the Veterans’ Administration Cooperative Study is that a number of patients voluntarily withdrew from the medically treated group and sought symptomatic relief through surgery. Sixteen per cent of patients in the cooperative study’s randomized medical group crossed over to surgical treatment [9]. It would appear that dropping these patients from follow-up at the time of crossover inserts bias by further improving the
206
Comparison of actuarial survival of the medically treated patients in the Veterans’ Administration Cooperative Study and the surgically treated patients in the present series has been made without consideration of the weaknesses and bias apparent in the Veterans’ Administration study. That study reported that 87 per cent of medically treated patients were alive compared to 88 per cent of patients treated surgically after three years. In our surgically treated series, which included patients with both unstable and stable angina plus those with many risk factors excluded from the Veterans’ Administration study, 92 per cent of patients were alive three years after operation. The Veterans’ Administration Cooperative Study follow-up extended only three years, but if their actuarial curves are projected to nine years, only 61 per cent of the medically treated patients will be anticipated to be alive, compared to 80 per cent of our surgically treated series. Summary
To ascertain whether surgical therapy increases the life expectancy of patients with coronary artery occlusive disease, 9,061 consecutive patients undergoing aortocoronary bypass from July 1968 through June 1977 were reviewed and followed for up to nine years. Among all patients undergoing aortocoronary bypass without concomitant procedures, early mortality was 3.5 per cent (9.1 per cent in 1970 and 1.7 per cent during 1977). Late mortality was significantly lower in those patients receiving four grafts or more (0.7 per cent) and triple grafts (2.2 per cent) compared with patients undergoing either double grafts (4.4 per cent) or single grafts (3.5 per cent). This emphasizes the importance of complete revascularization. Nine year follow-up determined that 91.0 per cent of surviving patients were asymptomatic or significantly improved. Actuarial (Cutler) curves including early and late mortality demonstrated that 92 per cent of patients were alive at three years and 80 per cent at nine years after aortocoronary bypass. These results compare favorably with those of the recently published randomized Veterans’ Administration Cooperative Study, which reported that at three years 87 per cent of medically treated patients were alive. Their follow-up extended only three years, but if their actuarial curves are projected to nine years, only 61 per cent of medically treated patients will be anticipated to be alive, compared to 80 per cent of patients
The American Journal of Surgery
Treatment of Coronary Artery Disease
surgically in the present series. These data suggest that surgical treatment of patients with coronary artery occlusive disease significantly improves long-term survival.
treated
15. 16.
Acknowledgments:
Acknowledgment and appreciation for technical assistance in the preparation of this manuscript are expressed to Mrs. Martha Moseley, Miss Mary McReynolds, RRA, MPH, Albert Gray, PhD, Ms. Joyce Staton, BS, Mr. James DeLeon, Mr. Russell Jones, BA, and Mrs. Judy Countryman. References 1. Hallman GL, Ccoley DA, McNamara DG, Labon JR: Single left coronary artery with fistulas to right ventricle: reconstruction of two coronary system with Dacron graft. Circulation 32: 293, 1965. 2. El-Said GM, Ruzyllo W. Williams RL, Mullins CE, Hallman GL, Cooley DA, McNamara DG: Early and late result of saphenous vein graft for anomalous origin of left coronary artery from pulmonary artery. Circulation 47 and 48 (Suppl Ill): 2, 1973. 3. Favaloro R: Saphenous vein autograft. Replacement of severe segmental coronary artery occlusion. Ann Thorac Surg 5: 334, 1968. 4. Johnson WD, Flemma RJ, Lepley D Jr, et al: Extended treatment of severe coronary disease: a total surgical approach. Ann Surg 170: 460, 1973. 5. Wukasch DC. Zorrilla L, Chu SH. Hall RJ. Hallman GL, Cooley DA: Combined coronary endarterectomy and saphenous vein bypass graft. Tex Med 69: 67, 1973. 6. Reul GJ Jr, Cooley DA, Wukasch DC, Kyger ER Ill, Sandiford FM, Hallman GL, Norman JC: Long-term survival following coronary artery bypass: analysis of 4,522 consecutive patients. Arch Surg 110: 1419, 1975. 7. Wukasch DC, Hall RJ, Cooley DA, Reul GJ Jr, Oglietti J, Kyger ER, Sandiford FM, Hallman GL: Surgical versus medical treatment of coronary artery disease: long-term survival. Vast Surg 10: 300, 1976. 8. Bruschke AVG. Proudfit WL, Sones FM Jr: Progress study of 590 consecutive nonsurgical cases of coronary disease followed 5-9 years. Circulation 47: 1147 1973. 9. Murphy ML, Hultgren HN. Detre K, et al: Treatment of chronic stable angina: a preliminary report of survival data of the randomized Veterans’ Administration Cooperative Study. NEnglJMed297: 621. 1977. 10. Braunwald E: Coronary artery surgery at the crossroads. N Engl J Med 297: 661, 1977. 11. Crawford ES, Wukasch DC, DeBakey ME: Hemodynamic changes associated with carotid artery occlusion: an experimental and clinical study. Cardiovasc Res Cent Bull 1: 3, 1962. 12. Wukasch DC, Toscano M, Cooley DA, Reul GJ Jr, Sandiford FM, Kyger ER Ill, Hallman GL: Reoperation following direct myocardial revascularization. Circulation (Suppl 2) 56: 11-3, 1977. 13. Cooley DA, Norman JC: Techniques in Cardiac Surgery. Houston, Tekas Medical, 1975, p 153. 14. Cooley DA, Wukasch DC. Bruno F. et al: Direct myocardial revascularization: experience with 9,364 operations. Pre-
17.
18.
sented at the Society of Thoracic and Cardiovascular Surgeons of Great Britain and Ireland, London, October 1977. Thorax (In press.) Cutler SJ, Ederer F: Maximum utilization of ihe life table method in analyzing survival. J Chronic Dis 8: 699, 1958. Wukasch DC, Cooley DA, Reul GJ Jr, Hall RJ, Vucinic M, Sandiford FM, Norman JC, Kyger ER Ill, Hallman GL: Surgical treatment of angina pectoris: current status. Angiology 28: 169, 1977. Detre K, Hultgren H, Takaro T: Veterans’ Administration Cooperative Study for coronary arterial occlusive disease. Ill. Methods and baseline characteristics, including experience with medical treatment. Am J Cardiol40: 212, 1977. Hall RJ. Cooley DA, Garcia E, Mathur VS. deCastro CM Jr: Does coronary bypass surgery prolong life expectancy? Presented at the ln&!mational Symposium: Coronary Heart Surgery-A Rehabilitation Measure, Bad Krozingen, West Germany, March 17-18, 1978.
Discussion Gerald M. Lawrie (Houston, TX): We have followed more than 1,500 patients, all operated on more than five years ago. All patients, regardless of whether they had one, two, or three vessel disease or left main arterial disease with reasonable preoperative left ventricular function, had a completely normal survival. Survival was depressed in patients with impaired left ventricular function. Perhaps the only difference is the number of grafts to perform. We have achieved these results doing an average of two grafts per patient. Patients with no residual disease in their three major vessels and with reasonable left ventricular function had above normal survival. The patient with two residual lesions had a 72 per cent survival. It is interesting to note that using just two grafts per patient or three or occasionally four, 84 per cent of the authors’ patients had significant major vessel residual disease. We are still not sure that it is necessary to perform a large number of grafts. Don C. Wukasch (closing): Among the 5,507 patients who underwent aortocoronary bypass procedures between October 1969 and June 1975, forty-one (0.007 per cent) developed recurrent angina and required reoperation. The factors necessitating reoperation were graft thrombosis in ten patients (24 per cent), progression of disease in twelve (29 per cent), graft thrombosis and critical unbypassed lesions in one (2.4 per cent), graft failure and progression of disease in twelve (29 per cent), graft failure and critical unbypassed lesions in four (10 per cent), and all three factors in two (4.8 per cent). Among ten patients with 50 per cent lesions present but not bypassed at the initial operation, nine of these lesions progressed to significant stenosis, and in five patients this was the sole reason for reoperation. This has influenced our thinking to the point that any lesion which is approximately 50 per cent in diameter should be bypassed at the time of initial operation.
End of Papers of Southwestern Surgical Congress
Volume 137, February 1979
207
Don C. Wukasch, MD, Houston, Texas Denton A. Cooley, MD, Houston, Texas Robert J. Hall, MD, Houston, Texas George J. Reul, Jr, MD, Houston, Texas Frank M. Sandiford, MD, Houston, Texas Sherri L. Zillgitt, BS, Houston, Texas
Direct reconstruction of congenital coronary artery anomalies by aortocoronary bypass was first performed in our hospital in 1963 [I], and long-term follow-up has demonstrated late patency of these grafts [2]. Subsequent application of this technic using autogenous saphenous vein grafts for acquired atheromatous coronary artery occlusive disease [3,4] has been proven successful in relief of angina pectoris in the majority of patients [5,6]. Long-term follow-up has suggested increased life expectancy in patients treated surgically [7] compared with those treated medically in the series of Bruschke, Proudfit, and Sones 181. Recent reports, however, advocating the efficacy of medical management of coronary artery occlusive disease, notably the Veterans’ Administration Randomized Cooperative Study [9], have created considerable controversy within the medical profession and confusion among patients. From these data, Braunwald [IO] suggested that surgical treatment of coronary artery occlusive disease does not prolong life expectancy. To ascertain whether surgical therapy does increase life expectancy in patients with coronary artery occlusive disease, all patients undergoing aortocoronary bypass surgery in our institution during the past nine years have been reviewed and the survival rates compared with those of the medically treated patients in the Veterans’ Administration Randomized Cooperative Study [9].
From the Divisions of Surgery and Cardiology, Texas Heart Institute of St. Luke’s Episcopal and Texas Chifdran’s Hospitals, and Ths Universityof Texas Health Science Center, Houston, Texas. Reprint requests should be addressed to Don C. Wukasch, MD, Texas Heart Institute, PO Box 20345. Houston, Texas 77025. Presented at the Thirtieth Annual Meeting of the Southwestern Surgical Congress, Palm Springs, California, April 17-20, 1978.
Volume 137, February 1979
Material and Methods Selection of Patients
All patients considered for myocardial revascularization were evaluated with stress electrocardiography and selective cineangiography, with complete mapping of the coronary arteries. The primary indication for operation was the presence of angina pectoris which interfered with the patient’s quality of life or work. Patients with unstable angina were not excluded from this study, and 17 per cent of patients exhibited unstable angina. A second group of patients in whom operation was performed were asymptomatic patients with ischemia on treadmill exercise testing and with angiographically demonstrated significant lesions in one or more major vessels, particularly the left main coronary artery. Approximately 8 per cent of patients in this series had significant stenotic lesions in the left main coronary artery. Although 75 per cent reduction in lumen diameter has frequently been considered to be the definition of a “significant” stenotic lesion, impedance of blood flow by an arteriosclerotic plaque depends not only upon the degree of lumen area occlusion produced, but also on the length of the obstruction [II]. Thus, a 50 per cent lumen area stenotic lesion 6 mm in length may produce the same reduction in blood flow as a 90 per cent lumen area lesion 1 mm in length. We believe that all lesions producing approximately 50 per cent stenosis should be bypassed at the time of aortocoronary bypass, because in our experience, nonbypassed 50 per cent lesions are one of the major factors in patients requiring reoperation after aortocoronary bypass due to progression of disease [121. Durmg the early period of our experience, severe left ventricular decompensation, with elevated end-diastolic pressure and reduced ejection fraction, was considered to be a contraindication for operation. Poor left ventricular function when accompanied by angina, however, is no longer considered to be a contraindication for aortocoronary bypass, unless there is angiographic evidence of diffuse disease in the distal vessels which would preclude
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TABLE I
All Cases of Coronary Bypass Surgery (July 1966 through June 30,1977) Procedure
No. of Patients
Coronary bypass only Left ventricular aneurysm resection Aortic valve procedure Mitral valve procedure Other associated procedures
9,061 683 384 281 243
Total
10.652
bypass. In the present series, the ejection fraction was reduced to less than 0.60 in 48 per cent of patients and to less than 0.45 in 18 per cent of patients. The indication for aortocoronary bypass in patients without angina but with symptomatic left ventricular dysfunction remains controversial. Our present impression is that patients with no angina and symptoms of congestive heart failure secondary to generalized left ventricular dysfunction, as opposed to those with the treatable complications of myocardial infarction, such as ventricular aneurysm, ventricular septal defect, or mitral valve incompetence, will benefit little from revascularization. We believe that preinfarction angina constitutes another indication for emergency aortocoronary bypass. Patients with uncontrollable ventricular arrhythmias associated with myocardial ischemia may also benefit from emergency revascularization. Patients experiencing uncontrollable cardiogenic shock after acute myocardial infarction can be frequently salvaged by intraaortic counterpulsation balloon pumping followed by emergency coronary arteriography and revascularization. satisfactory
Surgical Technic
The technics used in our revascularization procedures have been described in previous publications [13,14]. Most operations for myocardial revascularization were performed utilizing ischemic cardiac arrest under temporary cardiopulmonary bypass with hemodilution technics. When a localized stenosis of the right coronary artery was the only lesion present, bypass was performed without cardiopulmonary bypass. Since January 1977, cardioplegic solution at 5’C consisting of 500 cc of 5 per cent dextrose and 0.45 per cent sodium chloride, containing potassium chloride 15 mM, magnesium chloride 7.5 mM, sodium bicarbonate 2.5 mM, and calcium chloride 1.0 mM, has been injected into the ascending aorta after cross clamping. After cardiopulmonary bypass was begun by conventional technic, the heart was arrested and cooled topically. Distal anastomoses were performed with 6-O monofilament polypropylene continuous suture. Proximal anastomoses were performed with 5-O continuous suture after the aortic cross clamp was released and a partial occlusion clamp applied, permitting cardiopulmonary bypass to continue and restoring coronary perfusion. Optical magnification and fiberoptic lighting provided precision in anastomosing small arteries.
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Figure 1. Age and sex disfributton of patients undergoing aortocoronary bypass.
To decompress the arrested heart and provide a bloodless field for coronary anastomoses after the ascending aorta was cross clamped, a special aspirating needle was inserted into the ascending aorta and suction through a roller pump was applied, returning the aspirated blood to the extracorporeal circuit. This method prevents air from entering the cardiac chambers and eliminates the concern for air embolism. The technic of using sequential grafts (1 vein anastomosed side to side to 2 arteries or more) has enhanced the surgeon’s ability to revascularize all significant lesions. This technic is particularly applicable for multiple lesions in adjacent arteries and in patients having a limited length of available vein or a short ascending aorta which would make placement of five or six proximal anastomoses technically difficult. Endarterectomy is avoided when possible but is sometimes necessary in the occluded right coronary artery [5]. The saphenous vein is carefully removed and all branches are ligated in a manner that does not compromise the main lumen. Distension of the vein is accomplished with heparinized blood, since the vein wall may be injured when a saline solution is used. When the patient does not have saphenous veins that are suitable for the bypass, the alternative source of grafts is veins in the arm. The cephalic veins are more difficult to use because of lack of smooth muscle layers, but long-term results have been satisfactory. Internal mammary arteries have seldom been used in this institution and were reserved primarily for patients in whom no other vessel was available. Vascular substitutes were used in a few patients who had no other vessel availabIe, but the results were not promising. The need for a synthetic or biologic tissue substitute for the saphenous vein remains obvious. Clinical Material
Between July 1,1968 and June 30,1977, a consecutive series of 10,652 patients underwent aortocoronary artery bypass at the Texas Heart Institute. No patients were excluded from the series regardless of risk factors or severity
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Treatment of Coronary Artery Disease
15
1
Figure 3. Early moriaMy by year of study demonstrathg decline in mortalfty.
formed, early mortality for all patients undergoing aortocoronary bypass alone was 9.1 per cent (16 deaths among 175 patients). During 1977, early mortality in patients undergoing aortocoronary bypass alone declined to 1.7 per cent (26 deaths among 1,517 patients). (Figure 3;) Early Mortality Related to Sex. It has been apparent from the beginning of our experience that female patients with coronary artery disease represented a significantly higher risk of early death, as demonstrated in Table II, which reveals an early mortality of 6.6 per cent in female patients compared to 3.0 per cent in male patients during the entire series. During the most recent period of the study between January 1,1977 through June 30,1977, early mortality in male patients was reduced to 1.2 per cent but in female patients to only 4.6 per cent. (Table II.)
Figure 2. Distribution of patients by number of grafts performed.
of disease. Among these, 9,061 patients underwent aortocoronary bypass alone, and the remaining 1,591 underwent concomitant surgical procedures associated with cardiovascular dysfunction as shown in Table I. Among the 9,061 patients who underwent aortocoronary bypass alone, 86.6 per cent were males and 13.4 per cent females. The mean age of all patients was 54.1 years. (Figure 1.) The majority of patients were in the forty to sixty-nine year age group, although 433 patients were less than forty years old and 306 were more than seventy years old. As increased surgical experience has been acquired, an attempt has been made to bypass every stenotic coro-
nary artery which would permit a satisfactory anastomosis. In the entire series, 56.8 per cent of patients underwent three or more bypass graft procedures.
Late Mortality Related to Sex and Number of Grafts Required. Although early mortality was sig-
(Figure 2.)
nificantly higher in females than in males, the late mortality in males and females was similar: 2.9 per cent and 2.5 per cent, respectively. (Table III.) In both male and female patients, late mortality appeared to be lower in those patients in whom more complete revascularization was performed. (Table III.)
Results
Percentage of Early Mortality by Year. Early mortality (hospital death) has declined each year during the study, apparently the result of increasing technical experience. During 1970, the first year in which significant numbers of operations were per-
TABLE II
Early Mortality Related to Sex for Coronary Bypass Surgery Only July 1968 Through June 30, 1977 No. of No. of Patients Deaths Mot&y
January 1. 1977 Through June 30, 1977 No. of No. of Patients Deaths Mortality
Males Females
7,843 1,218
234 80
3.0% 6.6 %
1,298 219
16 10
1.2% 4.6%
Total
9,061
314
3.5 %
1,517
26
1.7%
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TABLE III
Late Mortality Related to Sex and Number of Grafts Required (June 1966 through June 30, 1977)’ Males No. of Deaths
Single vessel Double vessel Triple vessel Four vessels or more Total
Procedure
l
Total
Females Mortality
No. of Deaths
Mortality
6 13 8 1
2.8% 3.3% 1.9% 0.9%
32 126 82 8
3.5% 4.4% 2.2% 0.7%
28
2.5%
248
2.8%
Mortality
No. of Deaths
26 113 74 7
3.7% 4.6% 2.2% 0.7%
220
2.9%
From a total patient population of 9,061.
Causes of Death. Among 314 early deaths, the most common causes of death in both males and females were intraoperative or postoperative myocardial infarction, cerebrovascular accident, arrhythmia, and congestive heart failure. (Table IV.) The causes of late deaths were myocardial infarction, cerebrovascular accident, and congestive heart failure. (Table V.) Therefore, only approximately 50 per cent of late deaths were cardiac related. Long-Term Symptomatic Results. Analysis of symptomatic results among 4,928 patients in whom accurate follow-up information could be obtained demonstrated that male patients experienced slightly better symptomatic results than female patients. Ninety-two per cent of male patients remained either asymptomatic or significantly improved throughout the follow-up period, whereas 89 per cent of females remained in this category. (Table VI.) Comparison of long-term symptomatic results by number of vessels bypassed demonstrated consistent improvement in long-term symptomatic results as more vessels were bypassed. (Table VII.) Long-Term Suruiual. Actuarial surgical survival curves calculated by the life table method (Cutler) [15] to nine years demonstrated an annual attrition rate of 2.38 per cent. Three years after surgery 92 per cent were alive, and at nine years 79.6 per cent of patients were alive. (Figure 4.)
Comments
The reduction in early mortality from 9.1 to 1.7 per cent during the period of this study is encouraging and emphasizes the importance of increased surgical experience and improved technics. These include the use of cold cardioplegia, topical cardiac hypothermia, and greater technical precision provided by optical magnification and high intensity illumination. Improved early mortalities have resulted even though our indications for aortocoronary bypass have been broadened to include those patients who have angina pectoris in the presence of poor ventricular function (ejection fractions less than 0.2). As a rule, among patients with disabling angina pectoris, only those who have angiographic evidence of diffuse coronary arteriosclerosis which would preclude technically satisfactory grafts are refused operation [16]. When higher risk patients were excluded from the series, early mortality was approximately 1 per cent, a rate considered acceptable for most elective major surgical procedures. For example, in a recent consecutive series of patients from Holland, which excluded acute emergency cases, 268 underwent coronary bypass procedures with one death (0.4 per cent mortality) 1141.
TABLE V TABLE IV
Causes of Early Death After Coronary Bypass Surgery Only (July 1966 through June 1977)
Causes of Late Death After Coronary Bypass Surgery Alone (July 1966 through June 1977) No. of Patients
Cause of Death Cause of Death
l
204
No. of Patients*
Myocardial infarction Cerebrovascular accident Arrhythmia Congestive heart failure Hemorrhage Unknown Miscellaneous
128 56 49 35 6 18 22
Total
314 (100.0%)
From a patient population of 9,061.
Myocardial infarction Cerebrovascular accident Congestive heart failure Malignancy Arrhythmia Hemorrhage Thrombus Miscellaneous Unknown
(40.8%) (17.8%) (15.6%) (11.2%) (1.9%) (5.7%) (7.0%)
61 29 26 22 10 8 7 31 54
248 (100.0%)
Total l
(24.6%) (11.7%) (10.5%) (8.9%) (4.0%) (3.2%) (2.8%) (12.5%) (21.8%)
From a patient population of 9,061.
The American Journal of Surgery
Treatment of Coronary Artery Disease
TABLE VI
The higher early mortality in females compared with males is striking. Particularly notable is the fact that early mortality has been reduced considerably more in male than in female patients [ 71. A possible explanation for this difference may be that when coronary insufficiency develops in women, the metabolic derangement is more severe, thereby producing more diffuse lesions. Moreover, it has been our impression that the coronary arteries in women tend to be smaller, more friable, and more frequently intramyocardial in location than in men, thereby making satisfactory anastomoses technically more difficult. Curiously, for reasons that are not apparent, the higher risk of early mortality in females did not extend to late mortality, which was approximately the same for men and women. Once the female patient has survived operation, patency rates of the grafts in women are the same as in men. Support of the concept that a more severe metabolic derangement exists in women who develop coronary artery occlusive disease is suggested by the high surgical mortality in younger patients (aged 40 to 49 years). Most women in this age group are premenopausal and should have been protected somewhat from developing coronary artery occlusive disease. Apparently the arteriosclerotic process superseded the possible hormonal protection. Another factor to be considered is the higher incidence of diabetes among women. The importance of complete revascularization of ail stenotic coronary arteries is demonstrated by lower late mortality in those patients in whom more complete revascularization was achieved. In our opinion, the improved long-term survival outweighs the slightly higher early mortality associated with the more prolonged surgical procedure required for multiple bypass grafts. Additionally, our experience has revealed that complete revascularization of all lesions producing more than 50 per cent luminal stenosis is a major factor in reducing the need for subsequent “redo” revascularization procedures [12]. Moreover, the results clearly indicate better long-
TABLE VII
Patient Percentage* Males Females Total
Symptoms Asymptomatic or improved Symptoms unchanged Symptoms worse Unknown Total
92.0 4.0 2.0 2.0
89.0 5.0 4.0 2.0
91.0 4.0 3.0 2.0
100.0
100.0
100.0
From a patient population of 4,928 from whom follow-up data were obtained. l
term symptomatic relief with more complete revascularization. A recently published Veterans’ Administration Cooperative Study [9] of randomized patients with stable angina pectoris, one group receiving medical and the other surgical treatment, questions the efficacy of coronary artery revascularization in prolonging life [IO]. That study reported that 87 per cent of medically treated patients were alive compared to 88 per cent treated surgically three years after diagnosis. This cooperative study, however, has certain features that raise concern regarding the validity of their conclusions. First, the number of surgical patients from each of the cooperating hospitals was small and averaged less than ten patients per hospital per year. The Veterans’ Administration Study, thus, did not take into consideration the influence of surgical experience on operative mortality. The Veterans’ Administration Cooperative Study considered the period 1972 through 1974, during which time the operative mortality was 5.6 per cent, which is similar to our own early mortality of 4.4 per cent during this period. Use of this figure as anticipated early mortality for aortocoronary bypass, however, does not appear valid in view of current early mortality of 1.7 per cent in our own institution and similar figures from other large centers with greater surgical experience than
Long-Term Symptomatic Results for Patients Undergoing Coronary Bypass Surgery Only according to Number of Grafts
Symptoms Asymptomatic or improved Symptoms unchanged Symptoms worse Unknown Total l
Long-Term Symptomatic Results according to Sex for Coronary Bypass Surgery Only (July 1966 through June 30, 1977)
Single Vessel
Double Vessel
Percentage Incidence’ Triple 4 Grafts or Vessel More
Total
86 8 4 2
90 5 3 2
93 3 2 2
95 3 1 1
91 4 3 2
100
100
100
100
100
From a total patient population of 4,928.
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Wukasch et al
actuarial survival of the medically treated patients
@I-
I
2
3
4 5 SURVIVAL
6 7 TIME-YEARS
9
9
F/g~re 4. Actuarial curve comparin9 survival of entire Texas Heart lnstttute surgical series and Veterans’ AdmMstratton Cooperative Study medical series. ‘from [9]; l ‘from [8].
reported from the cooperating Veterans’ Administration hospitals. A second major weakness of the Veterans’ Administration Cooperative Study is that patients with major risk factors were not included. These factors are (1) unstable angina, (2) left main coronary artery lesions, and (3) being female. In contrast, our surgical series includes all patients, including 17 per cent with unstable angina, 8 per cent with left main coronary artery lesions, and 13.4 per cent female patients. In all other major areas of comparison, the patient populations of our study and the Veterans’ Administration Cooperative Study were similar. A third striking weakness of the Veterans’ Administration Cooperative Study is the bias in favor of the medically treated patients which appears to be introduced by exclusion before randomization of certain patients at physician or patient preference. Approximately 25 per cent of the Veterans’ Administration Cooperative Study patients .eligible for randomization were excluded because of death (8 per cent), unwillingness to enter the study (38 per cent), or “other” unspecified reasons (48 per cent) [17]. This exclusion of significant numbers of patients from randomization allows the possibility of patients exhibiting more severe disease having been diverted to nonrandomized surgical treatment. A fourth major weakness of the Veterans’ Administration Cooperative Study is that a number of patients voluntarily withdrew from the medically treated group and sought symptomatic relief through surgery. Sixteen per cent of patients in the cooperative study’s randomized medical group crossed over to surgical treatment [9]. It would appear that dropping these patients from follow-up at the time of crossover inserts bias by further improving the
206
Comparison of actuarial survival of the medically treated patients in the Veterans’ Administration Cooperative Study and the surgically treated patients in the present series has been made without consideration of the weaknesses and bias apparent in the Veterans’ Administration study. That study reported that 87 per cent of medically treated patients were alive compared to 88 per cent of patients treated surgically after three years. In our surgically treated series, which included patients with both unstable and stable angina plus those with many risk factors excluded from the Veterans’ Administration study, 92 per cent of patients were alive three years after operation. The Veterans’ Administration Cooperative Study follow-up extended only three years, but if their actuarial curves are projected to nine years, only 61 per cent of the medically treated patients will be anticipated to be alive, compared to 80 per cent of our surgically treated series. Summary
To ascertain whether surgical therapy increases the life expectancy of patients with coronary artery occlusive disease, 9,061 consecutive patients undergoing aortocoronary bypass from July 1968 through June 1977 were reviewed and followed for up to nine years. Among all patients undergoing aortocoronary bypass without concomitant procedures, early mortality was 3.5 per cent (9.1 per cent in 1970 and 1.7 per cent during 1977). Late mortality was significantly lower in those patients receiving four grafts or more (0.7 per cent) and triple grafts (2.2 per cent) compared with patients undergoing either double grafts (4.4 per cent) or single grafts (3.5 per cent). This emphasizes the importance of complete revascularization. Nine year follow-up determined that 91.0 per cent of surviving patients were asymptomatic or significantly improved. Actuarial (Cutler) curves including early and late mortality demonstrated that 92 per cent of patients were alive at three years and 80 per cent at nine years after aortocoronary bypass. These results compare favorably with those of the recently published randomized Veterans’ Administration Cooperative Study, which reported that at three years 87 per cent of medically treated patients were alive. Their follow-up extended only three years, but if their actuarial curves are projected to nine years, only 61 per cent of medically treated patients will be anticipated to be alive, compared to 80 per cent of patients
The American Journal of Surgery
Treatment of Coronary Artery Disease
surgically in the present series. These data suggest that surgical treatment of patients with coronary artery occlusive disease significantly improves long-term survival.
treated
15. 16.
Acknowledgments:
Acknowledgment and appreciation for technical assistance in the preparation of this manuscript are expressed to Mrs. Martha Moseley, Miss Mary McReynolds, RRA, MPH, Albert Gray, PhD, Ms. Joyce Staton, BS, Mr. James DeLeon, Mr. Russell Jones, BA, and Mrs. Judy Countryman. References 1. Hallman GL, Ccoley DA, McNamara DG, Labon JR: Single left coronary artery with fistulas to right ventricle: reconstruction of two coronary system with Dacron graft. Circulation 32: 293, 1965. 2. El-Said GM, Ruzyllo W. Williams RL, Mullins CE, Hallman GL, Cooley DA, McNamara DG: Early and late result of saphenous vein graft for anomalous origin of left coronary artery from pulmonary artery. Circulation 47 and 48 (Suppl Ill): 2, 1973. 3. Favaloro R: Saphenous vein autograft. Replacement of severe segmental coronary artery occlusion. Ann Thorac Surg 5: 334, 1968. 4. Johnson WD, Flemma RJ, Lepley D Jr, et al: Extended treatment of severe coronary disease: a total surgical approach. Ann Surg 170: 460, 1973. 5. Wukasch DC. Zorrilla L, Chu SH. Hall RJ. Hallman GL, Cooley DA: Combined coronary endarterectomy and saphenous vein bypass graft. Tex Med 69: 67, 1973. 6. Reul GJ Jr, Cooley DA, Wukasch DC, Kyger ER Ill, Sandiford FM, Hallman GL, Norman JC: Long-term survival following coronary artery bypass: analysis of 4,522 consecutive patients. Arch Surg 110: 1419, 1975. 7. Wukasch DC, Hall RJ, Cooley DA, Reul GJ Jr, Oglietti J, Kyger ER, Sandiford FM, Hallman GL: Surgical versus medical treatment of coronary artery disease: long-term survival. Vast Surg 10: 300, 1976. 8. Bruschke AVG. Proudfit WL, Sones FM Jr: Progress study of 590 consecutive nonsurgical cases of coronary disease followed 5-9 years. Circulation 47: 1147 1973. 9. Murphy ML, Hultgren HN. Detre K, et al: Treatment of chronic stable angina: a preliminary report of survival data of the randomized Veterans’ Administration Cooperative Study. NEnglJMed297: 621. 1977. 10. Braunwald E: Coronary artery surgery at the crossroads. N Engl J Med 297: 661, 1977. 11. Crawford ES, Wukasch DC, DeBakey ME: Hemodynamic changes associated with carotid artery occlusion: an experimental and clinical study. Cardiovasc Res Cent Bull 1: 3, 1962. 12. Wukasch DC, Toscano M, Cooley DA, Reul GJ Jr, Sandiford FM, Kyger ER Ill, Hallman GL: Reoperation following direct myocardial revascularization. Circulation (Suppl 2) 56: 11-3, 1977. 13. Cooley DA, Norman JC: Techniques in Cardiac Surgery. Houston, Tekas Medical, 1975, p 153. 14. Cooley DA, Wukasch DC. Bruno F. et al: Direct myocardial revascularization: experience with 9,364 operations. Pre-
17.
18.
sented at the Society of Thoracic and Cardiovascular Surgeons of Great Britain and Ireland, London, October 1977. Thorax (In press.) Cutler SJ, Ederer F: Maximum utilization of ihe life table method in analyzing survival. J Chronic Dis 8: 699, 1958. Wukasch DC, Cooley DA, Reul GJ Jr, Hall RJ, Vucinic M, Sandiford FM, Norman JC, Kyger ER Ill, Hallman GL: Surgical treatment of angina pectoris: current status. Angiology 28: 169, 1977. Detre K, Hultgren H, Takaro T: Veterans’ Administration Cooperative Study for coronary arterial occlusive disease. Ill. Methods and baseline characteristics, including experience with medical treatment. Am J Cardiol40: 212, 1977. Hall RJ. Cooley DA, Garcia E, Mathur VS. deCastro CM Jr: Does coronary bypass surgery prolong life expectancy? Presented at the ln&!mational Symposium: Coronary Heart Surgery-A Rehabilitation Measure, Bad Krozingen, West Germany, March 17-18, 1978.
Discussion Gerald M. Lawrie (Houston, TX): We have followed more than 1,500 patients, all operated on more than five years ago. All patients, regardless of whether they had one, two, or three vessel disease or left main arterial disease with reasonable preoperative left ventricular function, had a completely normal survival. Survival was depressed in patients with impaired left ventricular function. Perhaps the only difference is the number of grafts to perform. We have achieved these results doing an average of two grafts per patient. Patients with no residual disease in their three major vessels and with reasonable left ventricular function had above normal survival. The patient with two residual lesions had a 72 per cent survival. It is interesting to note that using just two grafts per patient or three or occasionally four, 84 per cent of the authors’ patients had significant major vessel residual disease. We are still not sure that it is necessary to perform a large number of grafts. Don C. Wukasch (closing): Among the 5,507 patients who underwent aortocoronary bypass procedures between October 1969 and June 1975, forty-one (0.007 per cent) developed recurrent angina and required reoperation. The factors necessitating reoperation were graft thrombosis in ten patients (24 per cent), progression of disease in twelve (29 per cent), graft thrombosis and critical unbypassed lesions in one (2.4 per cent), graft failure and progression of disease in twelve (29 per cent), graft failure and critical unbypassed lesions in four (10 per cent), and all three factors in two (4.8 per cent). Among ten patients with 50 per cent lesions present but not bypassed at the initial operation, nine of these lesions progressed to significant stenosis, and in five patients this was the sole reason for reoperation. This has influenced our thinking to the point that any lesion which is approximately 50 per cent in diameter should be bypassed at the time of initial operation.
End of Papers of Southwestern Surgical Congress
Volume 137, February 1979
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