Operative Risk in Patients with Previous Coronary Artery Bypass

Transcription

1 Operative Risk in Patients with Previous Coronary Artery Bypass E. Stanley Crawford, M.D., George C. Morris, Jr., M.D., Jimmy F. Howell, M.D., William F. Flynn, M.D., and Dudley T. Moorhead, M.D. ABSTRACT Noncoronary operations were performed in 358 patients who had undergone a previous coronary artery bypass grafting, with a mortality of 1.1%. In 70 patients (20%), the staged operation was planned and subsequent operation performed 6 to 12 weeks after bypass with no cardiac complications and 1 death. In the others, operation was performed 10 days to 89 months after bypass for either urgent reasons or new lesions. Three deaths and significant numbers of medical cardiac complications occurred in those patients subjected to operation within 30 days. The subsequent operation was vascular in 232 patients, with 3 deaths (1.3%); thoracic in 43, with no deaths; and general surgical in 113, with 1 death (0.9%). Follow-up study showed 307 patients (87%) still alive after 30 days to seven years. Late death was due to myocardial infarction in.only 12 patients (3%). This study suggests that the risk of operation is as good in patients who have had successful coronary artery bypass as in those without coronary artery disease, and that the risk of subsequent myocardial infarction is small. Patients with coronary artery disease are well known to be at increased risk during a major operation, having a higher postoperative mortality, a greater incidence of postoperative myocardial infarction, and a shorter life expectancy. Recent studies indicate that in all forms of coronary artery disease, even those not producing symptoms, patients undergoing hysterectomy, urological procedures, herniorrhaphy, or mastectomy face an operative mortality several times that of patients without coronary artery disease [l, 2, 81. Other studies show that the risk varies with both the severity of heart dis- From the Cora and Webb Mading Department of Surgery, Baylor College of Medicine and The Methodist Hospital, Houston, TX. Presented at the Fourteenth Annual Meeting of The Society of Thoracic Surgeons, Jan 23-25, 1978, Orlando, FL. Address reprint requests to Dr. Crawford, Baylor College of Medicine, 1200 Moursund Ave, Houston, TX ease and the type of operation. For example, the risk of operation after myocardial infarction ranges from 7 to 77% depending upon the severity of infarction and the interval between infarction and operation [2]. The operative mortality following resection of an abdominal aortic aneurysm in patients with atherosclerotic heart disease is documented to be about 12% [3, 111. Moreover, the five-year survival rate in these patients is only 51'/0, compared with 81% for a general population of similar age and sex [31. The difference is largely due to the higher incidence of cardiac problems in patients with coronary artery disease. Several recent reports suggest that successful coronary artery bypass performed before vascular operations decreases this risk [5, 6, 9, 101. We are in agreement with this opinion, and we present here our experience with coronary artery bypass and subsequent operations of all types. Clinical Material Coronary artery bypass operations have been performed in 6,800 patients by the senior authors during the past nine years. Our experience includes patients with angina, preinfarction syndromes, previous myocardial infarction, acute myocardial infarction, lesions of the left main coronary artery, valve disorders, ventricular aneurysm, and impaired left ventricular function as well as patients previously undergoing operation elsewhere. The operative mortality in these patients was 4.1%. Of the surviving patients, 358 underwent a variety of other major operations performed by the authors or their associates at Methodist Hospital, Houston, TX, from 10 days to 89 months after bypass. This sampling of the bypass population forms the basis of our study. Excluded are the relatively large number of patients having simultaneous operation, principally carotid endarterectomy, since these have been previously reported and are irrelevant to the present study by E. Stanley Crawford

2 216 The Annals of Thoracic Surgery Vol 26 No 3 September 1978 Table 7. Clinical Indications for Coronary Bypass in 358 Patients Table 2. Number of Bypass Grafts lnserted per Patient in 358 Patients Indication Patients Angina 304 (85%) Myocardial infarction 45 (13%) Heart failure 4 (1%) Other 5 (1%) Total 358 (1000/0) Grafts One Two Three Total Patients 93 (26%) 207 (58%) 58 (16%) 358 (100%) I 1235) 0 Pre coronary artery bypass Pre-second procedure 1179) n II Ill IV NYHA CLASS I FlCATl ON Fig 1. Functional classification of 31 1 patients. [7]. Also excluded are those patients who underwent subsequent reoperation for coronary artery disease and those who had subsequent operations elsewhere. It was necessary to exclude this latter group because it was not possible to obtain the details necessary for the analysis required by this study. There were 307 men and 51 women in the present series, ranging in age from 33 to 76 years with a mean age of 56 years at the time of bypass. The clinical indications for coronary bypass are shown in Table 1. The New York Heart Association Functional Classification of those who could be classified prior to the second operation is shown in Figure 1. Most of the patients were in either Class I11 or Class IV before coronary artery bypass grafting, and most had reverted to Class I or I1 before the second operation. The number of grafts inserted per patient is shown in Table 2. The majority of patients treated in the past six years had multiple grafts, whereas single grafts were more frequent in our earlier experience. Coronary arteriography was performed prior to the second operation in 149 patients, 76 of Table 3. Subsequent Operative Procedures in 358 Patients Procedures One Two Three or more Total Pa ti en ts 266 (74%) 70 (20%) 22 (6%) 358 (looo/o) whom had symptoms. All grafts inserted were patent in 101 patients (67%), and one or more grafts were patent in 141 patients (94%). Angiography was performed much more commonly in symptomatic patients; consequently, we suspect that the true incidence of patients with at least one patent graft is higher than 94%. Of interest is the fact that of 39 patients studied five years or longer after bypass, one or more grafts were patent in 38 (97%) and all grafts were patent in 31 (79%). Subsequent Operations The 358 patients in this study were subjected to 484 subsequent operations. The majority had only one subsequent operation; however, a large number had several procedures (Table 3). Subsequent operations were planned before coronary bypass in 70 patients (20%) and were performed between 6 weeks and 3 months after bypass in most instances. The remaining operations were for new or previously unrecognized conditions and were performed 10 days to 89 months after bypass. Subsequent operations were performed within a month of bypass in 5% of the patients and within two years of bypass in 65% of the patients (Fig 2). The types of operations performed were aor-

3 217 Crawford et al: Operative Risk with Previous CAB Table 5. Types of Aortic and Peripheral Vascular Procedures Carried Out in 232 Patients Operation Procedures Deaths MONTHS Fig -3. Interval between coronary artery bypass and subsequent operation. Table 4. Types of Operations Performed after Bypass in 358 Patients Oper- Procedure ations Patients Deaths Aortic and (1.3%) peripheral vascular Thoracic General (0.9'/0) surgical Total (1.1%) Carotid endarterectomy 97 2 Aortofemoral bypass 53 0 Abdominal aortic aneurysm 49 0 Thoracic aortic aneurysm 3 1 Femoral artery bypass 39 0 Sympathectomy 7 0 Other 60 0 Total (1.3%) Table 6. Types of Thoracic Procedures Carried Out in 43 Patients Operation Procedures Pacemaker insertion 17 0 Chest wall resection 17 0 Pulmonary embolectomy 1 0 Pulmonary resection 11 0 Esophageal resection 2 0 Total 48 0 Table 7. Types of General Surgical Procedures Carried Out in 113 Patients Deaths tic and peripheral vascular in 232 patients (308 operations), thoracic in 43 patients (48 operations), and general surgical in 113 patients (128 operations) (Table 4). The most common aortic and peripheral vascular operations performed were carotid endarterectomy in 97 patients, aortofemoral bypass in 53, resection and graft replacement for abdominal aortic aneurysm in 49, and femoropopliteal artery bypass in 39 (Table 5). Other operations included vena cava ligation, brachial artery repair, peripheral aneurysm, embolectomy, and carotid-subclavian bypass. Pacemaker implantation, chest wall procedures, and pulmonary resections constituted the majority of thoracic procedures (Table Operation Procedures Deaths Gallbladder 32 0 Bowel resection 8 0 Hiatus hernia 4 0 Thyroid 4 0 Gastrectomy 4 0 Surface procedure 40 0 Other 36 1 Total (0.9%) tients. The general surgical procedures are listed in Table 7. Surface procedures included mastectomy, hernia repairs, skin grafts, and re- 6). Of the 11 pulmonary resections, 9 were for section of tumors of the skin and subcutanecancer of the lung and 2 for benign granuloma- ous tissues requiring general anesthesia. Other tous disease. Esophageal resection was per- operations included Whipple procedures, formed for cancer of the esophagus in 2 pa- splenectomy, excision of abdominal wall, pos-

4 218 The Annals of Thoracic Surgery Vol 26 No 3 September 1978 terior excision of rectum, colostomy, exploratory laparotomy, and amputation. Indications for Subsequent Operation The indications for subsequent operation were those commonly employed in patients with similar disease, and the proportion of elective and urgent indications was essentially the same as that in the general population except in the few patients with unimproved Class I11 or IV functional status. The indications for operation in these patients were more urgent and compelling than those in the general population. Results There were 4 deaths (l.l0/o) after the 484 subsequent operations in these 358 patients (see Tables 4-7). Death was due to stroke in 2 patients after the second of a staged bilateral carotid endarterectomy procedure for transient cerebral ischemic attacks. One patient died from hemorrhage during operation for a dissecting aneurysm of the ascending aorta. One patient died five years after coronary artery bypass from an extensive abdominal wall resection for synergistic bacterial gangrene. This patient had had a splenectomy 6 weeks previously for hypersplenism due to chronic leukemia. No deaths were of cardiac origin. In the survivors, myocardial infarction occurred in 6 patients, and troublesome rhythm disturbances that extended the hospital stay complicated recovery in 14 other patients. Most of the complications and 3 of the 4 deaths occurred in patients 'subjected to subsequent operation within 30 days of coronary artery bypass grafting. In this regard, it may be pertinent that none of the 70 patients in whom subsequent procedures were planned before coronary artery bypass and carried out 6 weeks to 3 months later died or had major cardiac complications. The functional results of operation were considered excellent. Patients surviving carotid endarterectomy were relieved of symptoms of cerebrovascular insufficiency. Death did not occur in the 102 patients requiring abdominal aortic operation or in the 39 who had femoral artery bypass grafting. All patients undergoing thoracic procedures survived, as did most undergoing general surgical operations. Current I I I I I YEARS Fig 3. Actuarial estimate of five-year survival after first secondary procedure. follow-up information has been obtained in 97.5% of these patients since their first subsequent operation. Of the 354 surviving patients, 307 (87%) were still alive 30 days to seven years after operation. The cause of death in 29 of the 47 patients who died late was cancer or pulmonary or renal problems. The cause of death was unknown in 6. Of the 9 patients who underwent operation for cancer of the lung, 4 died later of their disease. Four patients are alive and well, 3 from one to three years and the other for more than five years after operation; 1 patient is lost to follow-up. Death was of cardiac origin in 12 patients (3%). An actuarial survival curve was constructed for survival following the first subsequent operation (Fig 3). Using this method, we concluded that a patient who has recovered from coronary artery bypass and requires one or more subsequent operations that are in most instances for other arteriosclerotic lesions has a 70% chance of living for five years after the operation. Comment The extremely high initial survival rate and the good functional results of subsequent operations after successful coronary artery bypass, as shown in this study and others, suggest that coronary artery bypass reduces operative mortality from complications of coronary artery disease. Moreover, our study suggests that coronary artery bypass reduces the incidence of myocardial infarction and death in the followup period. For example, in this series 49 patients underwent resection of abdominal aortic

5 219 Crawford et al: Operative Risk with Previous CAB aneurysm, and all survived, in contrast to the accepted mortality of 12% in such patients. Nearly equal numbers of patients were subjected to aortofemoral and femoropopliteal artery bypass grafting without a death. Prior to coronary artery bypass, most of these patients would not have been operated on because of the risks and because claudication produced the necessary limitation of activity. Now, after relief of angina and of the need for restricted activity, patients are insisting upon relief of claudication. Of interest is the fact that only 12 (3%) of the 354 patients who survived subsequent operations have died from myocardial infarction during the follow-up period since their first subsequent operation. The predicted five-year survival rate was 70% for the entire group having multiple operations for more than one lesion, which is 18% less than that expected in the general population. Thus combinations of operations did not restore life expectancy to normal; in fact, the attrition rate gradually widened to the disadvantage of the patients requiring operation. Consideration must be given, however, to the fact that the most serious forms of disease, including cancer and multiple arteriosclerotic lesions, were concentrated in this series of cases; consequently, a five-year survival of 70% may be considered satisfactory. Comparison of actuarial estimates of longterm survival for patients in each group with estimates for a similar group who did not have previous coronary artery bypass grafting would be helpful in determining the advantages of coronary artery bypass for long-term survival. This comparison is not possible at present, since there are not enough patients in each group in our series to allow a valid comparison. Enough patients had coronary artery bypass followed by carotid endarterectomy for us to make a short-term comparison after carotid endarterectomy with confidence (Fig 4). The survival rate of patients undergoing coronary artery bypass and then carotid endarterectomy in this series was compared to that of a similar group of patients who had coronary artery disease and carotid artery obstruction treated by carotid endarterectomy alone [41. At the end of three years, the survival rate of patients undergoing the combined procedure was 15% better than 80 ' 1 loo (73%) 40 0 CAB fdlmved by endarterectomy 2o 0 Coronary artery disease, no CAB. endarteredomy PERIOD OF SURVIVAL IN YEARS Fig 4. Survival rate of patients undergoing carotid endarterectomy. (CAB = coronary artery bypass.) that of patients undergoing endarterectomy alone. Regardless of this encouraging finding, we can say only that major operation after successful coronary artery bypass is as safe as it is in a patient who does not have coronary artery disease. Further, we would advise postponing the second operation for 6 weeks to 3 months whenever possible, since most of the complications in our series occurred when operation was performed within 30 days of bypass. References 1. Alexander S: Surgical risk in the patient with arteriosclerotic heart disease. Surg Clin North Am 48:513, Arkins R, Smessaert AA, Hicks RG: Mortality and morbidity in surgical patients with coronary artery disease. JAMA 190:485, DeBakey ME, Crawford ES, Cooley DA, et al: Aneurysm of abdominal aorta: analysis of results of graft replacement therapy one to eleven years after operation. Ann Surg 160:622, DeBakey ME, Crawford ES, Cooley DA, et al: Cerebral arterial insufficiency: one to ll-year results following arterial reconstructive operation. Ann Surg 161:921, Edwards WH, Mulherin JL Jr, Walker WE: Vascular reconstructive surgery following myocardial revascularization. Ann Surg 187:653, McCollum CH, Garcia-Rinaldi R, Graham JM, et al: Myocardial revascularization prior to subsequent major surgery in patients with coronary artery disease. Surgery 81:302, Morris GC Jr, Ennix CL, Lawrie GM, et al: Management of coexistent carotid and coronary artery occlusive atherosclerosis, Proceedings of The First Decade of Bypass Graft Surgery for Coronary Artery Disease, an International Symposium, Cleveland, OH, Sept 15-17, Cleve Clin Q 45:125, 1978

6 220 The Annals of Thoracic Surgery Vol 26 No 3 September Nachlas MM, Abrams SJ, Goldberg MM: The influence of arteriosclerotic heart disease on surgical risk. Am J Surg 101:447, Reis RL, Hannah H 111: Management of patients with severe, coexistent coronary artery and peripheral vascular disease. J Thorac Cardiovasc Surg 73:909, Scher KS, Tice DA: Operative risk in patients with previous coronary artery bypass. Arch Surg 111:807, Young AE, Sandberg GW, Couch NP: The reduction of mortality of abdominal aortic aneurysm resection. Am J Surg 134:585, 1977 Discussion DR. GEORGE c. KAISER (St. Louis, MO): Dr. Crawford has presented a typical Houston series, both from the standpoint of numbers and beautiful results. Of approximately 7,000 patients who underwent myocardial revascularization, 5% had a subsequent operation of another type with a 1% mortality. This rate is indeed rather remarkable. About two-thirds of the reoperations were for vascular problems other than the initial one. In 49 of the patients abdominal aortic aneurysmectomy was performed, and additional patients were treated for obstructive aortoiliac disease. There were no operative deaths in these groups. This result can be compared with the published mortality for aneurysmectomy of 10 to 12% in patients who have associated coronary artery disease. If anything, this improved survival in these high-risk groups should add credence to the prophylactic benefits of coronary artery bypass grafting. The experience at my institution has been similar from the standpoint of mortality and frequency of vascular operations. We have noticed one other group of patients who have required additional operative treatment following bypass grafting. These patients complain of impotence after the angina pectoris has disappeared. Urologists at our institution have implanted a Scott prosthesis in these patients with gratifying results. I wonder if Dr. Crawford s group has had any experience with this particular problem. Another question for Dr. Crawford relates to the association of coronary artery and peripheral vascular disease. In the present study, about 5% of the patients seen with coronary artery disease had associated symptomatic vascular disease. This has been our experience also, and we have wondered about this low incidence since, in patients seen with symptomatic peripheral vascular disease, the incidence of coronary disease is much higher. In view of this difference, how does Dr. Crawford currently screen patients who come to him with symptomatic peripheral vascular disease, and how does he determine the sequence of operations if myocardial revascularization is indicated in addition to another vascular procedure? DR. JOHN HINES KENNEDY (Gates Mills, OH): Speaking as a former Baylor faculty member, I would like to compliment Dr. Crawford on his excellent results in this large series of patients. I have one question which concerns the patient who has had a vein bypass graft and concomitant valve replacement, requires life-long anticoagulant therapy, and faces an operative procedure for which management of the anticoagulant therapy during the second perioperative period may be a problem. It has been my experience that when such patients undergo mastectomy, for example, no problems have accrued when warfarin therapy is discontinued a day or two before operation, anticoagulant therapy is not reversed with antagonist medication, and anticoagulants are resumed as soon as the drains are removed. Some surgical situations, such as those involving the eye, the brain, or the urological system, may represent a special case. I have had no experience with such exceptions. DR. JOHN c. NORMAN (Houston, TX): As of December 30,1977, our aortocoronary bypass series at the Texas Heart Institute numbered 12,310 procedures. The overall operative mortality for bypass without other procedures was 3.6%. We agree with Dr. Crawford that after aortocoronary bypass the patient is essentially free of coronary artery occlusive disease. We appreciate that since atherosclerosis is a generalized process, patients frequently have carotid and peripheral vascular disease in conjunction with it. We have reported similar combined operations in the Bulletin of the Texas Heart Institute (Coronary artery occlusive disease: current pandemic and surgical inroads. Cardiovasc Dis, Bull Texas Heart Inst 226, 1975). May I ask Dr. Crawford how he deals with carotid stenosis in a patient who needs aortocoronary bypass? We have noted an apparent higher incidence of neurological complications when the carotid and revascularization operations are done together. While we frequently repair a hiatal hernia and remove an abdominal aneurysm or gall bladder at the same operation, we are hesitant to combine cardiopulmonary bypass with carotid surgery. DR. LUIS A. TOMATIS (Grand Rapids, MI): Since June, 1968, we have studied patients with peripheral vascular disease by simultaneous peripheral and coronary transbrachial angiography. Of the patients who had a normal electrocardiogram and no history of angina, myocardial infarction, or congestive heart failure, 16% had severe coronary artery disease (75 to 99% occlusion) and 12% had moderately severe disease (50 to 75% occlusion) in 1 or more coronary arteries. Based on these findings, for the past nine years in some patients, we have simultaneously operated on the coronary and peripheral lesion, performed ab-

7 221 Crawford et al: Operative Risk with Previous CAB dominal aneurysm excision, and done femoropopliteal and aortoiliac bypass; or we have staged the procedures, doing the coronary bypass first. During this period we have had no cardiac deaths in elective vascular procedures. DR. CRAWFORD: I would like to thank all who discussed this paper; their comments were interesting and added knowledge to the subject. Dr. Kennedy poses the problem of managing the patient on anticoagulants following cardiac operation who is about to undergo another operation. I recommend discontinuing anticoagulants, restoring the coagulation factors to normal by the time of second operation, and resuming anticoagulants 24 hours after the operation. Rare situations may require some form of anticoagulation during this interval; under these conditions, I recommend "low dose heparin" because bleeding could be more easily controlled should it occur. Sexual impotence has not been a major problem. In our patient population, it would seem that the opposite is much more common. In fact, anginal pain during intercourse is a frequent complaint and was a factor in the decision to perform coronary artery bypass. Fortunately, bypass surgery that relieves angina has restored sexual bliss to numerous couples. Should impotence be a problem, I am confident that a patient who had a successful bypass procedure could safely undergo penile implantation if the attending urologist and psychiatrist judged the implantation worthwhile. The presence of other conditions in association with coronary artery disease is a common problem, and the timing of treatment has not been entirely settled by clinical studies. However, sufficient experience is now available to indicate that a cerebrovascular operation can be performed safely at the time of a bypass procedure with better survival and with fewer strokes and myocardial infarctions than if the surgical treatment of the two lesions is staged. In abdominal aortic aneurysm, an associated condition, simultaneous bypass and aneurysm replacement has been performed because of the progressive nature of the angina and signs of aneurysmal leakage. Similarly, a bypass procedure has been performed simultaneously with aortic and femoral artery reconstruction in patients with angina and peripheral gangrenous changes. Although therapy was successful and most patients survived, our experience is limited and final conclusions cannot be drawn from it. I conclude from Dr. Norman's remarks that Dr. Cooley routinely treats the other lesion, regardless of type and location, at the time of bypass with uniform success. He deserves to be congratulated and encouraged to present this experience in detail for analysis. Meanwhile, we will continue to defer the treatment of associated conditions that are not urgent, except cerebrovascular disease, until patients have fully recovered from bypass operation.