Resection of abdominal aortic aneurysm patients with low ejection fractions

Transcription

1 Resection of abdominal aortic aneurysm patients with low ejection fractions in Richard L. McCann, MD, and Walter G. Wolfe, MD, Durham, N.C. The perioperative and long-term survival of patients who undergo resection of abdominal aortic aneurysm is often determined by coexisting cardiac disease. This study evaluates the influence of left ventricular ejection fraction on both perioperative and long-term morbidity and mortality. Preoperative ejection fraction was measured in 104 of 208 patients undergoing elective abdominal aortic aneurysm resection. Nineteen patients were found to have ejection fractions less than 0.35, and this group was compared to 85 patients with ejection fractions greater than The two groups did not differ significantly in terms of age, sex, preoperative renal fimction, or smoking status. The groups were significantly different with respect to the prevalence of prior myocardial infarction (79% of the low ejection fraction group vs 31% of the high ejection fraction group) and symptoms equivalent to New York Heart Association class II or greater (47% of the low ejection fraction group vs 24% of the high ejection fraction group) but not prior myocardial revasoalarization procedure (42% of the low ejection fraction group vs 31% of the high ejection fraction group). Surgical factors including aneurysm size, duration of aortic crossdamping, and extent of arterial replacement did not differ significantly between the two groups. The perioperative mortality was not significantly different (low ejection fraction, 5%; high ejection fraction, 2%). The cumulative life-table survival of the two groups was not statistically different. Two patients in the low ejection fraction group died in the follow-up period, yielding a 4-year actuarial survival of This is compared to 10 deaths and actuarial survival of 0.63 (p = NS) in the high ejection fraction group. We conclude that patients should not be denied aneurysm resection solely on the basis of left ventricular ejection fraction. (J VAse SURG 1989;10:240-4.) Concomitant cardiac disease has been considered the most important determinant of survival in the elective surgical treatment of abdominal aortic aneurysm (AAA). Because of this strong influence, some have advocated the routine or even prophylactic use of preoperative coronary angiography and coronary bypass grafting in an effort to limit cardiacrelated morbidity and mortality, 1 Others have advocated a more selective approach. 2 Improvement in perioperative morbidity and mortality rates has not been shown by taffy prophylactic coronary bypass surgery in patients with peripheral vascular disease, a Prognosis in coronary disease is markedly influenced by the functional status of the left ventricle and the anatomic status of the coronary arteries. Patients found to have diminished left ventrieular ejection fraction (EF) after acute myocardial infarction do From the Duke University Medical Center. Presented at the Thirteenth Annual Meeting of the Southern Association for Vascular Surgery, Key West, Fla., Jan , Reprint requests: Richard L. McCann, MD, P.O. Box 2990, Duke University Medical Center, Durham, NC /6/14118 have a reduced survival expectancy. However, the magnitude of this reduction is currently debated and may be improved with appropriate surgical intervention. 4 With respect to AAAs Kazmers et al. a have suggested that patients with EFs!ess than 0.35 ere not benefited by surgery. We have previously documented a reduction in left ventricular performance at the time of aortic cross-clamping in patients undergoing aneurysm resection. However, these studies also show prompt recovery ofventricular performance after release of the aortic cross-clamp. These observations combined with general improvements in monitoring and anesthetic technique have led us to aggressively recommend resection of aneurysms even in patients with known impairment of ventricular performance. In the current study we have determined the long-term fate of these patients by follow-up of up to 4 years after surgery to determine if the long-term mortality justifies such an aggressive approach. PATIENTS AND METHODS The charts of 208 consecutive patients undergoing elective AAA resection were reviewed. Of this group, 104 patients had preoperative determinations 240

2 Volume 10 Number 3 September 1989 Abdominal aortic aneurysm survival 241 Table I. Clinical characteristics of patients undergoing AAA resections with EF >0.35 (high EF) and EF <0.35 (low EF) High EF LOW EF p No Age (mean) NS Men (%) 85% 95% NS Follow-up (mo) NS Range (1-48) (1-47) Smokers (%) 30% 26% NS Creatinine 1.4 _ NS -+ SD Table II. Cardiac risk factors in 85 patients with high EF and 19 patients with low EF undergoing AAA repair High EF Low EF Risk factor ~ No. % No. % p >NYHA Class II 20 24% 9 47% p < 0.05 Prior MI 36 31% 15 79% p < 0.01 Prior CABG/PTCA 26 31% 8 42% p = NS ~NYHA, New York Heart ~ssociation, MI, myocardial infarction; CABG, coronary artery bypass gaffing; PTCA~ percutaneous transluminal coronary angioplasty, of left ventricular EF by first pass or multigated radionuclide angiocardiography. Patients with known preoperative left ventricular EFs were stratified arbitrarily into low and high EF groups. To conform to other reports and to facilitate comparisons, a resting left ventricular EF of 0.35 or less was considered to indicate significant ventricular impairment and was found in 19 patients. Eighty-five patients were placed in the second group, and each had an EF greater than The clinical characteristics of these two groups were compared to determine if important differences exist between them other than for functional status of the left ventricle. The series extends from January 1985 to December Each of the patients or their physicians were contacted to establish their current status. Follow-up in this group is 100% complete to the end of the study. Survival was calculated by the life-table method, and computergenerated survival curves were comparcd by the Wilcoxon log rank test (SAS Institute, Cary, N.C.). For statistical comparisons between groups t tests were computed (Statgraphics, STSC Inc., RockviUe, Md.) for numeric data, and chi-square tests were used for frequency data. A significance level of 0.05 was chosen. RESULTS The clinical features of the two groups are shown in Table I. The two groups were not statistically different with respect to any of the clinical criteria of age, sex, tobacco use, or preoperative renal function. The average follow-up was between 11/2 and 2 years for each group and ranged from i month to 4 years. Follow-up was more than 2 years for 37% of the patients. The cardiac risk factors are listed in Table II. Almost half of the patients in the low EF group had cardiac symptoms equivalent to New York Heart Association class II or greater. Fifteen (79%) of the patients in the low EF group had had a documented Table III. Surgical factors in patients undergoing AAA repair with high and low cardiac EF Surgical factor High EF Low EF p Aneurysm size NS (cm -+ SD) Cross-clamp time NS (min SD) Tube graft (%) 70% 68% NS prior myocardial infarction. This compared to 31% of the patients in the high EF group. The cardiac disease was due to defined or undefined cardiomyopathy in four patients in the low EF group. Fortytwo percent of the patients in the low EF group had undergone prior myocardial revascularization as had 31% of the patients in the high EF group. The surgical aspects were remarkably similar between the two groups. Aneurysm size, aortic crossclamping time, and extent of arterial replacement as indicated by use of tube grafts are compared in Table III. No significant differences occurred in any of these variables. The cardiac EFs are listed in Table IV. Those patients placed in the high EF group who survived had an average EF of 0.61 compared to 0.56 in patients who died (p = NS). The survivors in the group of patients with low EFs had an average EF of 0.27 compared I:o 0.24 in patients who died (p = NS). For a smaller group of patients, EF was measured at exercise with a bicycle ergometer. In this smaller group the average EF of survivors was also slightly but not statistically significantly greater than exercise EF in patients who died. Long-term survival The cttmulative life-table survival for the two groups is shown in Fig. 1. Two perioperative deaths occurred in the high EF group (2%). Both of these

3 242 A/lcCann and Wolfe Jo~nai of VASCULAR SURGERY.J or o r ) LIJ _>._1 1.5 t , T I - 1,2.6 1 Wileoxon Log Ronk Test - Chi-Squore = 0.63 p = NS s6 2, I, Low EF High EF I 1 I MONTHS Fig. 1. Life-table survival curves for the follow-up period for patients with low and high EFs. Number of patients completing each interval are shown above file line and standard error of the estimate is shown. No statistically significant difference occurred between these cumulative life-table survival curves by the Wilcoxon log rank test (chi square = 0.63, p = NS). Table IV. Cardiac EF in survivors and patients who died perioperatively and up to 4 years postoperatively by preoperative EF H~h EF Low EF Survivors Deaths Surpivors Deaths No. EF No. EF p No. EF No. EF p Rest EF NS NS -+ SD Exercise EF NS NS +SD were due to sudden deaths presumed to be caused by cardiac disease. One of the 19 patients with EFs less than 0.35 died perioperatively (5 % ). This patient suffered a fatal myocardial infarction on the eighth postopcrative day after an uneventful course until that time. Ten patients in the high EF group died in the follow-up period. Most of these deaths have been related to coronary or cerebral atherosclerosis. The causes of death are listed in Table V. Only two patients in the group with low EFs died during the follow-up period of up to 47 months. One of these deaths was sudden and presumed to be cardiac related. The other death was due to progressive pulmonary insufficiency 17 months after aneurysm re- section. No statistically significant difference between the life-table survival of these patients with low EF occurred compared to the patients with high EFs. DISCUSSION Since the report by Dubost et al.7 in 1952 of the first successful AAA resection, much improvement has occurred in the treatment of these patients. The initial 17% operative mortality has been reduced to 3% to 5% or even lower in elective resections, s,9 The natural history of untreated AAA has remained constant. Despite the occurrence of atherosclerotic disease at other sites, 30% to 50% of these patients will experience rupture if their aneurysms are not treated

4 Volume 10 Number 3 September 1989 Abdominal aortic aneurysm survival 243 surgically. 8a,n Little dispute exists that patients with AAAs who are good surgical risks should undergo elective aneurysm resection. The long-term survival of these patients rivals that of age-matched controls2 The patient who has a physiologic impairment that might increase surgical risk or compromise life expectancy is more controversial. Significant improvements in the medical treatment of patients with chronic renal disease and chronic pulmonary insufficiency have markedly reduced the influence of these diseases on surgical outcome in patients with aneurysms. 12'13 The current study as well as others 9,14 suggest that a similar process is occurring for cardiac dysfunction. In our 19 patients with severely impaired ventricular function, coronary artery disease was responsible for the heart disease in 15, and the remaining four had defined or undefined cardiomyopathy. Not all of these patients had severe symptoms and in fact slightly more than half were labeled New York Heart Association class I for angina and failure. This suggests that a high index of suspicion should be maintained, and liberal use of preoperative evaluation of cardiac function should be encouraged. The mortality of patients found to have severely reduced left ventricular EF immediately after myocardial infarction is high. Nicod et al. is found a 26% first-year mortality after myocardial infarction in patients with left ventricular EFs less than 40%. The survival advantage seen in our patients may be explained by several factors. Of primary importance is that the diminished mortality associated with left ventricular EF is primarily associated with patients immediately after they suffer myocardial infarction. The patients in our study were somewhat selected in that any patients who had suffered a myocardial infarction within the previous 6 months had undergone coronary bypass surgery or percutaneous transluminal coronary angioplasty in the interim. Results from the registry of the coronary artery surgery Study suggest a more favorable prognosis in patients with reduced EF, particularly if operable coronary artery disease is corrected. In this study cumulative 5-year survival of 78% in surgically treated patients is reported. ~6 The favorable longevity in our survivors of aneurysm resection with low EF is in contrast to a recent report by Kazmers et al. 5 A possible explanation for this discrepancy is that the latter series consists almost entirely of patients from the Veterans Administration Hospital with a high degree of associated impairment in other systems, which may Table V. Causes of death in patients with high and low EF after aneurysm resection Cause of death High EF Low EF Perioperative 2 (2%) 1 (5%) Postoperative 10 2 Cardiac 4 1 Stroke 2 Pulmonary 2 1 Other 2 Total 1--2 affect the total morbidity and long-term mortality in this specific population. We think based on this review of our experience over the last 4 years, that standard transabdominal aneurysm resection can be performed in patients with diminished left ventricular reserve, and an acceptable perioperative mortality can be achieved. Moreover, our data suggest that with careful medical treatment the long-term survival of these patients justifies an aggressive surgical approach to patients with AAAs. We think that a reduced left ventricular EF alone is not sufficient clinic~ ground on which to deny a patient aneurysm resection. REFERENCES 1. Hertzer NR, Young JR, Beven EG, et al. Late results of coronary bypass in patients with infrarenal aortic aneurysms. Ann Surg 1987;205: Reigel MM, ~Hollier LH, Kazmier FJ, et al. Late survival in abdominal aortic aneurysm patients: the rote of selective myocardial revascularization on the basis of clinical symptoms. J VASC SURG 1987;5: Hollier LH, Plate G, O'Brief PC, et al. Late survival after abdominal aortic aneu~sm repair: influence of coronary artery disease. J VASC SUKG 1984;1: Vigilante GJ, Weintraub WS, Klein LW, et al. Improved survival with coronary bypass surgery in patients with three vessel coronary disease and abnormal left ventricular fianction. Am J Med 1987;82: Kazmers A, Cerqueira MD, Zierler RE. Perioperative and late outcome in patients with left ventricular ejection fraction of 35% or less who require major vascular surgery. J VAse SURG 1988;8:307-!5. 6. Harpole DH, Clements FM, Quill T, Wolfe WG, Jones RH, McCann RL. Right and left ventricular performance during abdominal aortic repair. Ann Surg 1989;209: Dubost C, Allary M, Oeconomos N. Resection of an aneurysm of the abdominal aorta. Reestablishment of the continuity by a preserved human arterial graft with result after five months. Arch Surg 1952;64: Thompson JE, HoUier LH, Pa~an RD, Persson AV. Surgical management of abdominal aortic aneurysms. Ann Surg 1975;181: Perry MO, Calcagno D. Abdominal aortic aneurysm surgery:

5 244 McCann and Wolfe Journal of VASCULAR SURGERY the basic evaluation of cardiac risk. Ann Surg 1988;208: Szilagyi DE, Elliott JP, Smith RF. Clinical fate of the patient with asymptomatic abdominal aortic aneurysm and unfit for surgical treatment. Arch Surg 1972;104: Gliedman ML, Ayers WB, Vestal BL. Aneurysms of the abdominal aorta and its branches. A study of tmtreated patients. Ann Surg 1957;146: Cohen JR, Marmick JA, Couch NP, Whittemore AD. Abdominal aortic repair in patients with preoperative renal failure. J VASC SURG 1986;3: Smith PK, Fuchs JC, Sabiston DC. Surgical management of aortic abdominal aneurysms in patients with severe pulmonary insufficiency. Surg Gynecol Obstet 1980;151: Hollier LH, Reigel MM, Kazmier FJ, Pairolero PC, Cherry KJ, Hallett JW Jr. Conventional repair of abdominal aortic aneurysm in the high-risk patient: a plea for abandonment of nonresective treatment. J VASC SURG 1986;3: Nicod P, Gilpin E, Dittrich H, et at. Influence on prognosis and morbidity of left ventricular ejection fraction with and without signs of left ventricualr failure after acute myocardial infarction. Am J Cardiol 1988;61: Mock MB, Fisher LD, Holmes DR Jr, et al. Comparison of effects of medical and surgical therapy on survival in severe angina pectoris and two vessel coronary artery disease with and without left ventricular dysftmction: a coronary artery surgery study registry study. Am J Cardiol 1988;61: BOUND VOLUMES AVAILABLE TO SUBSCRIBERS Bound volumes of the JOURNAL OF VASCULAR SURGERY for 1989 are available to subscribers only. They may be purchased from the publisher at a cost of $52.00 ($66.00 international) for Vol. 9 (January to June) and Vol. 10 (July to December). Price includes shipping charges. Each bound volume contains a subject and author index, and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the vokune. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact Circulation Fulfillment, The C.V. Mosby Company, Westline Indnstrial Drive, St. Louis, MO , USA. In the United States call toll free: (800) , ext In Missouri call collect: (314) , ext Subscriptions must be in force to qualify. Bound vohmaes are not available in place of a regular JOURNAL subscription.