Coronary Artery Bypass Surgery in Patients Over Age 70 Years: Report from the Milwaukee Cardiovascular Data Registry

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1 Clin. Cardiol. 10, (1987) Original Contributions Coronary Artery Bypass Surgery in Patients Over Age 70 Years: Report from the Milwaukee Cardiovascular Data Registry G. DORROS, M.D., R. F. LEWIN, M.D.,*P. DALEY, M.D.,J. ASSA, M.S. Medical College of Wisconsin and * St. Luke s Hospital, Milwaukee, Wisconsin, USA Summary: Between 1972 and 1985,674 coronary bypass patients 2 70 years (70% male, mean age 73 years) were among 10,622 patients with both catheterization and operative data entered into the Milwaukee Cardiovascular Data Registry. These 2 70 years patients were analyzed regarding the operative morbidity, the 30day operative mortality, and the operative mortality s relation to coronary artery disease and ventricular wall motion abnormalities. The operative mortality was not different for the 174 patients operated upon before and the 500 patients after A mean of 3.4 grafts were placed during surgery. The complications encountered included a 7.1 % perioperative infarction rate, a 4.2% incidence of cerebrovascular accident, a 3.6% incidence of reoperation for bleeding, a 2.4% incidence of renal failure, and a 2.1 % incidence of pulmonary embolism. The overall operative mortality was 7.4%. The extent of coronary artery disease was distributed among patients such that 8.4% had single, 28.0% had double, and 63.6 % had triplevessel disease. The operative mortality as related to the extent of coronary artery disease was 5.2% for single, 8.9% for double, and 7.0% for triplevessel disease. The operative mortality was 6.7% with no and 7.9% with left ventricular wall motion abnormalities. The operative mortality was 1.9% with 1 segmental wall motion abnormality, and increased to 13.3% (~~0.05) with 46 segmental wall motion abnormalities. The operative mortality for singlevessel disease was 5.4% with normal and 4.3% with abnormal wall motion; for Address for reprints: Gerald Donos, M.D. Associate Professor of Medicine St. Luke s Health Sciences Building 2901 W. Kinnickinnic River Parkway Suite 512 Milwaukee, WI 53215, USA Received: Febmary 23, 1987 Accepted: April doublevessel disease it was 4.3 % with normal and 13.2 % with abnormal wall motion, (~~0.05); and, for triplevessel disease, 8.3% with normal and 6.0% with abnormal wall motion. Actuarial lifetable analysis indicated that the probability of surviving at least 7 years is 64.6 f 3.6 I. There was no difference in the survival at 4 years regardless of the extent of coronary disease. After 4 years, the difference in survival between single and triplevessel disease became significant (single, 91 % versus triple, 78%; p<0.05). The probability of survival at 7 years was affected by the presence of wall motion abnormalities (normal, 73% versus abnormal, 5696, ~ ~0.05). These data suggest that coronary bypass surgery when performed in patients 2 70 years has a significant operative mortality which is probably not related to the extent of coronary artery disease, but to the severity of left ventricular wall motion abnormalities. Surviving patients have a relatively good longterm outlook which, nevettheless, is adversely affected by the extent of coronary disease, and the severity of left ventricular wall motion abnormalities. Key words: bypass surgery, geriatric population, longterm followup, lifetable analysis Introduction Patients greater than age 70 years constitute a growing segment of our population whose relatively good health may be m d by symptomatic coronary disease. Comnary artery bypass graft surgery has been utilized reluctantly to treat selected members of this symptomatic geriatric population because of the associated significant surgical morbidity and This communication will report the Milwaukee Cardiovascular Data Registry s experience of patients over the age of 70 years who underwent their fht coronary bypass surgical pmedure with regard to the operative mortality and the 30day operative mortality s relationship to the extent of coronary artery disease, and to the severity of left ventricular wall motion abnormalities.

2 378 Clin. Cdiol. Vol. 10, July 1987 Methods The Milwaukee Cardiovascular Data Registry is a voluntary registry, composed of cardiovascular surgeons and cardiologists which has compiled data on patients who underwent cardiac surgery since Between 1972 and 1985,10,622 patients have been entered into the Milwaukee Cardiovascular Data Registry, with complete surgical and catheterization data, who underwent their first myocardial revascularization surgery without any concomitant surgical procedures (i.e., valve replacement, aneurysmectomy, Vineberg implant, or carotid endarterectomy). Followup data was obtained by yearly written questionnaires. There were 674 patients over age 70 years who were operated upon, and their catheterization and surgical data were analyzed with regard to the operative mohidity, and the 30day operative mortality and its relationship to the extent of coronary artery disease and presence or absence of left ventricular wall motion abnormalities. Analysis of the relationship of the extent of coronary disease and left ventricular wall motion abnormalities was done by grouping patients into single, double, and triplevessel disease, and relating the absence (normal) or presence (abnormal) of left ventricular wall motion abnormalities to each pup. The singlevessel group was too small to analyze since it consisted of 57 patients of whom 20 had left ventricular dysfunction. Patient followup utilizing the lifetable methodz1 was performed to show the effect of the extent of coronary disease and the presence of left ventricular wall motion abnormalities upon longterm survival. Complications, apart from mortality, were not included in the Data Registry forms. A review of the computerized patient records was performed in order to determine the incidence of complications as listed by the operator at hospital discharge. The complications listed included cerebrovascular accident, transient ischemic attack, postoperative myocardial infaxtion, postoperative renal failure, postoperative wound infection, pulmonary embolism, and mperation for bleeding. Data on myocardial revascularhation has been collected by the Milwaukee Cardiovascular Data Registry since However, during the early years of bypass surgery, few operations were performed upon patients over 70 years of age. Therefore, a retrospective data analysis was begun with cases performed between January 1972 and December Selective coronary arteriography and left ventricular angiography had been performed in each patient prior to surgery. Coronary attery disease was defined as a 2 50% diameter stenosis in a major epicardial coronary artery. As previously repo~ted, ~ data on ventricular wall motion obtained from the coronary angiogmn were recorded for each of six left ventricular segments utilizing the right anterior oblique view: high, mid and low segments in the inferior wall and high, mid and low segments in the anterior wall. The ventriculogram was divided into six segments. For each of the left ventricular segments, the wall motion was classified as normal, hypokinetic, akinetic, or dyskinetic. All data is presented as mean value f standard deviation, apart from lifetable analysis where the standard error is utilized. Comparison between groups was done utilizing Chisquare analysis for discrete variables. Results Between 1972 and 1985, there were 674 patients over the age of 70 years who underwent their first bypass surgery (Table I). Because of changes in surgical techniques, patient selection, and the concept of a surgical learning curve, a comparative study was performed to determine if there was a difference in the 30day operative mortality between the early ( , 174 patients) and late ( ,500 patients) experience of the registry. No statistically significant difference was found between these two groups regarding their age, sex, extent of coronary disease, left ventricular dysfunction, or operative mortality. Further analyses were performed on the group as a single entity, and all data presented represented the entire group. Despite the fact that doublevessel and triplevessel coronary disease accounted for 91.6% of the patient population, the operative mortality (Table II) did not differ significantly between single, double, or triplevessel disease. Even utilization of an occlusion score systemz3 which weighted the individual coronary vessels as to their vary TABLE I Clinical characteristics of patients greater than 70 Y Patients Male Female Mean age (yrs) Mean graftstpatient One graft Two grafts Three grafts Four grafts Five grafts Six or more grafts Distribution of coronary disease Singlevessel disease Doublevessel disease Triplevessel disease Left ventricular function Normal (i.e., no abnormalities) 13 Abnormal segments 4 Abnormal segments 5 Abnormal segments 6 Abnormal segments (70%) 203 (30%) 73 f (4.7%) 118 (17.5%) 224 (33.2%) 174 (25.9%) 96 (14.3%) 30 (4.4%) 57 (8.5%) 189 (28.0%) %) 309 (45.8%) 278 (41.2%) 36 (5.3%) 24 (3.6%) 27 (4.1%)

3 TABLE I1 Relationship of the extent of coronary disease and left ventricular wall motion abnormalities to the 30day operative mortality G. Dorms et al.: Bypass surgery in patients L 70 years 379 Mortality related to extent of coronary disease Overall 50 (7.4%) Singlevessel disease 3 (5.2%) Doublevessel disease 17 (8.9%) Triplevessel disease 30 (7.0%) Mortality related to ventricular wall motion abnormalities Normal left ventricular wall motion 21 (6.7%) Abnormal left ventricular wall motion 29 (7.9%) 1 Abnormal segment 2 (1.9%) 23 Abnormal segments 15 (8.9%) 46 Abnormal segments 12( 13.3 %) Mortality related to extent of coronary artery disease and left ventricular wall motion abnormalities Singlevessel disease Normal 2 (5.4%) Abnormal 1 (4.9%) Doublevessel disease Normal 4 (4.3%) Abnormal 13(13.2%) Triplevessel disease Normal 15 (8.3%) Abnormal 15 (6.0%).18 FIG. 1 Lifetable analysis of bypass surgery patients over age 70 years. The parentheses ( ) express the population at risk at the end of each year. n=674. ing importance likewise showed no effect upon the 30 day operative mortality. The 7.4% mortality for patients over 70 years was significantly increased (p<0.05) above the Data Registry's mortality of 2.0% for all patients 5 70 years (a 1.6% mortality with normal left ventricular wall motion versus a 2.4% mortality with multiple left ventricular wall motion abnormalities, p <0.05). This must be contrasted to the geriatric patients in whom the mortality with normal left ventricular wall motion was 6.7% (Table 11), and significantly increased to 13.3% (p ~0.05) with multiple left ventricular wall motion abnormalities. In the presence of doublevessel disease, the mortality significantly increased (~0.05) from 4.3% with normal (none) to 13.2% with abnormal (multiple) left ventricular wall motion abnormalities. The mortality for triplevessel disease was high, and significantly (p < 0.05) increased only in the late group with 46 abnormal ventricular wall motion segments (mortality, 18%). Followup data was analyzed using the lifetable method. Despite the relatively high surgical mortality, the surviving patients had (Fig. 1) a 61 % probability of being alive at 8 years. There was no statistically significant difference in the cumulative survival at 3 years regardless of the extent of coronary disease (Fig. 2). However, at 4 years, the difference in survival between singlevessel and triplevessel disease became statistically significant (single vessel, 91 % versus triple vessel, 78%; pc0.05). The cumulative survival (Fig. 3) at 7% years did depend o1 i 5 B d h ci t I Years FIG. 2 Lifetable analysis of bypass surgery patients over age 70 years and the relationship of survival and the extent of coronary artery disease. The population at risk at the end of each period for each group is shown. SVD () =singlevessel disease; DVD ( ) =doublevessel disease; TVD ("") =triplevessel disease. upon left ventricular function (a 73 % survival with normal ventricular wall motion versus a 56% survival with abnormal ventricular wall motion, pc0.05). The complications encountered are listed in Table III. These complications were not mutually exclusive. Nine of the 24 patients who required a reoperation for bleeding had an additional complication including myocardial infarction (2 1 %), cerebrovascular accident (4 % ), renal failure (12%), pulmonary embolism (4%), and wound infection (4%).

4 380 Clin. Cadiol. Vol. 10, July 1987 ".. NLF250 NLF216 NLF161 NLF119 KLFW NLF54 NLF35 NLFaD ABNLF ABNLF ABNLF ABNLF WNLFABNLFABNLFABNLF W IS FIG. 3 Lifetable analysis of bypass surgery patients over age 70 years and the relationship of survival and left ventricular function (N. LF ()=normal left ventricular function; ABN. LF ( )= abnormal left ventricular function). The population at risk at the end of each period is shown at the bottom of the figure. Discussion Coronary artery bypass graft surgery has been utilized reluctantly to treat selected geriatric patients because of the reported associated significant surgical morbidity and mortality (Table IV). By and large, the published data concerning patients over 70 years of age who have undergone coronary artery bypass surgery is limited. The number of published reports with morbidity statistics are few. The mortality statistics have varied, with the mortality in some groups remaining relatively high while one report showed a decline in their high mortality statisticss which was attributed to the surgical learning experience. However, in our study, there was no difference in the lack of decrease in mortality between the early and late surgical experience. This lack of difference may actually represent improvements in surgical techniques and surgical experience which enabled more difficult surgical cases to be attempted which TABLE III Complications' encountered in coronary artery bypass surgery in patients over age 70 years Postoperative myocardial infarction 47 (7.1%) Cerebrovascular accident 28 (4.2%) Reoperation for bleeding 24 (3.6%) Postoperative renal failure 16 (2.4%) Pulmonary embolism 14 (2.1%) Postoperative wound infection 11 (1.7%) Transient ischemic attack 5 (0.8%) a Complications encountered were not mutually exclusive. had higher surgical risks. However, as in every retrospective study involving the use of dynamic variables (i.e., surgical techniques, patient selection, surgical experience), the data must always be viewed with this in mind. However, this problem should not prevent analysis of such retrospective data which still can provide us with important information. Reported morbidity associated with myocardial revascularization surgery is difficult to find. Fm ef al. repotted a 10.5% operative mortality in 105 patients over the age of 70 along with significant morbidity figures: cerebrovascular accidents in 8.6 %, mperation for bleeding in 8.5 %, red failm in 5.7 %I. Cardiac complications including myocardial infarction, congestive heart failure, and arrhythmias were present in 44.8% of cases. However, the vast majority of surgical reports fail to list comorbidity statistics. Therefore, the assessment of the incidence of possible postoperative complications in the geriatric patient [including neurologic deficits (tmnsient or permanent), perioperative infarctions, or other cardiovascular, pulmonary or renal problems] is difficult, if not impossible, to achieve. The fact that the morbidity in this patient group is not negligible is supported by our data. In addition, within our series, reoperation for surgical bleeding increased the likelihood of additional concomitant complications. The mortality of the geriatric population remains significant even if the mortality statistics are stratified for age. In the coronary artery surgical study,9 the mortality increased with increasing age: Age 6569, 4.6%; 7074, 6.6%; and, 1 75 years, 9.5%. The overall surgical mortality of 7.9% of the Milwaukee Cardiovascular Data Registry is in keeping with the previously published reports. However, analysis of this 30day operative mortality with regard to the extent of coronary disease and its relationship to left ventricular wall motion abnormalities is unique. Mortality was not adversely affected by the extent of coronary artery disease, but was related to the presence of significant left ventricular dysfunction. The cumulative probability of survival for the group was 61 % at 8 years after surgery. Survival was adversely affected by the extent of left ventricular wall motion abnormalities. In addition, longterm survival (more than 4 years) was adversely affected by the extent of coronary disease. Since the initial success (the first 4 years after surgery) showed no difference in survival, the subsequent significant difference in survival may be a reflection of the progression of coronary disease, and not an event related to surgery. It has been suggested in nonmndomized series of medical versus surgicaltreated groups2' that age is the only detrimental factor in their longterm prognosis. Our data suggest that geriatric patients (over age 70 years) who cannot be medically managed can undergo myocardial revascularization surgery with a reasonable although significant operative mortality, and that the expected longterm survival rates are good in the patients who survive surgery. The extent of coronary disease should be the indication for direct myocardial revascularization surgery,

5 G. Dorms et al.: Bypass surgery in patients 2 70 years 381 TABLE IV Coronary artery bypass surgery in the elderly patient: mortality and morbidity Patient Age Ref. >65 yrs 170 yrs Mortality CVA Periopeative MI Confusion 1 total: 10" " a Patients 170 yrs 6 Male Female (11) (283) (5.1%) 2 (9.1%) 6 (6.0%) 1 (5.9%) 4 (10%) 3 (6.3%) 9 (4.3%) 8 (2.8%) 21 (22.1%) 0 (0%) 10 (15.6%) 4 (8.0%) 1 (2.9%) 1 (2.9%) 10 (11.8%) 1 (2.8%) 2 (3.1%) 2 (1.7%) 57 (2.7%) 20 (7.1%) 11 (10.5%) 5 (6.0%) 6 (28.6%) 74 (5.8%) 22 (13.9%) 52 (4.7%) 2 (2.0%) 2 (4.2%) 16 (6.0%) 1 (2.0%) 2 (2.4%) 4 (11.4%) 2 (3.1%) 3 (2.5%) 9 (8.6%) 2 (2.0%) 1 (5.9%) 2 (4.2%) 15 (5.7%) 6 (6.3%) 1 (1.5%) 5 (10.0%) 3 (8.6%) 10 (11.8%) 3 (8.6%) 3 (4.6%) 4 (3.3%) "Refs. 10 and 21 may include repetitious data. Abbreviations: CVA =cerebrovascular accident (tmnsient or permanent neurologic deficit); MI =myocardial infarction. whereas ventricular function as determined by wall motion abnormalities must be clearly defined, so as to permit an accurate assessment of the perioperative risk. Clearly, elderly patients sufficiently symptomatic to warrant myocardial revascularization surgery for the first time did so because symptomatic coronary disease impaired their functional capacity, and not because of an expectation of increased longevity. Surprisingly, the 8year probability of survival of the entire group was 61 %, which means that nearly two thirds of these symptomatic geriatric patients might be expected to live to age 81. Perhaps, myocardial revascularization surgery may have contributed to this unexpected increase in longevity. These findings require corroboration by further studies. References 1. Ashor GW, Meyer BW, Lindesmith GG, Stiles QR, Walker GH, Tucker BL: Coronary artery disease: Surgery in 100 patients 65 years of age and older. Arch Surg 107, 30 (1973) 2. Barnhorst DA, Guilian ER, Pluth JR, Danielson GK, Wallace RB, McGoon DC: Openheart surgery in patients more than 65 years old. Ann 7korac Surg 18, 81 (1974) 3. Berry BE, Acree PW, Davis DT, Sheely CH, Cavin S: Coronary artery bypass operations in septuagenerians. Ann Thorac Surg 31, 310 (1981) 4. DuCailar C, Chaitman BR, CastonGuay Y: Risks and benefits of aortocoronary bypass surgery in patients aged 65 years or more. Can Med Assoc J 122, 771 (1980) 5. Elayda MA, Hall RJ, Gray AG, Mathur VS, Cooley DA: Coronary revascularization in the elderly patient. J Am Coll Cardi 01 3, 1398 (1984) 6. Faro RS, Golden MD, Javid H, Seny C, DeLaria G, Monson D, Weinberg M, Hunter JA, Najafi H: Coronary revascularization in septuagenarians. J lhorac Cardiovasc Surg 86, 616 (1983) 7. Gann D, Colin C, Hildner FJ, Samet P, Yarh WZ, Greenberg JJ: Coronary artery bypass surgery in patients seventy years of age and older. J lhorac Cardiovusc Surg 73, 237 (1977) 8. Garcia JM, Cheanvechai C, Effler DB: Myocardial revascularization in patients aged 65 and older. Cardiovasc Clin 7, 83 (1975) 9. Gersh BJ, Kronmal RA, Frye RL: Coronary arteriography and coronary artery bypass surgery: Morbidity and mortality in patients aged 65 years or older. Circulation 67, 483 (1983)

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