Abdominal aortic aneurysm and coronary artery disease: Frequent companions, but an uneasy relationship

Abstract

The study of McEnroe et al.1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar again affirms the important relationship between abdominal aortic aneurysm (AAA) and coronary artery disease. More than one half of this patient population undergoing elective AAA repair had either reversible myocardial ischemia (36%) by thallium-201 redistribution or prior infarction (16%) with a fixed defect suggested by dipyridamole thallium scintigraphy (DTS). These findings are consistent with the results of routine coronary angiography in a series of 302 patients with AAA studied at the Cleveland Clinic.2Young JR Hertzer NR Beven EG et al.Coronary artery disease in patients with aortic aneurysm: a classification of 302 coronary angiograms and results of surgical management.Ann Vasc Surg. 1986; 1: 36-42PubMed Google Scholar Only 15% of patients with clinically suspected ischemic heart disease were found to have no disease or mild to moderate coronary disease (<70% luminal stenosis); 54% of patients without suspected coronary disease had similar angiographic findings. Among patients with significant coronary stenoses, there was a spectrum of single (46%), double (33%), and triple (21%) vessel disease.2Young JR Hertzer NR Beven EG et al.Coronary artery disease in patients with aortic aneurysm: a classification of 302 coronary angiograms and results of surgical management.Ann Vasc Surg. 1986; 1: 36-42PubMed Google Scholar Acute myocardial infarction and other complications of ischemic heart disease account for most (60% to 70%) perioperative mortality,3Diehl JT Cali RF Hertzer NR Beven EG. Complications of abdominal aortic reconstruction: an analysis of perioperative risk factors in 557 patients.Ann Surg. 1983; 197: 49-56PubMed Google Scholar, 4Brown OW Hollier LH Pairolero PC Kazmier FJ McCready RA. Abdominal aortic aneurysm and coronary artery disease: a reassessment.Arch Surg. 1981; 116: 1484-1488Crossref PubMed Scopus (153) Google Scholar, 5Reigel MM Hollier LH Kazmier FJ et al.Late survival in abdominal aortic aneurysm patients: the role of selective myocardial revascularization on the basis of clinical symptoms.J Vasc Surg. 1987; 5: 222-227PubMed Scopus (121) Google Scholar and is also responsible for 38% to 70% of all late deaths after AAA repair.5Reigel MM Hollier LH Kazmier FJ et al.Late survival in abdominal aortic aneurysm patients: the role of selective myocardial revascularization on the basis of clinical symptoms.J Vasc Surg. 1987; 5: 222-227PubMed Scopus (121) Google Scholar, 6Hollier LH Plate G O'Brien PC et al.Late survival after abdominal aortic aneurysm repair: influence of coronary artery disease.J Vasc Surg. 1984; 1: 290-299PubMed Scopus (155) Google Scholar, 7Roger VL Ballard DJ Hallett Jr, JW Osmundson PJ Puetz PA Gersh BJ. Influence of coronary artery disease on morbidity and mortality after abdominal aortic aneurysmectomy: a population-based study, 1971-1987.J Am Coll Cardiol. 1989; 14: 1245-1252Abstract Full Text PDF PubMed Scopus (155) Google Scholar. In a comprehensive literature review Hertzer8Hertzer NR. Basic data concerning associated coronary disease in peripheral vascular patients.Ann Vasc Surg. 1987; 1: 616-620Abstract Full Text PDF PubMed Scopus (149) Google Scholar found that 41% to 56% of patients undergoing operation for peripheral vascular disease (47% in patients having AAA repair) had clinical evidence of coronary disease. In patients studied by coronary angiography, “serious” coronary disease was found in 57% of patients with lower extremity ischemia and in 65% of those with AAA. The operative mortality for all types of vascular surgery was 1.1% to 2.9% in patients without overt coronary disease, versus 4.7% to 9.6% in patients with suspected or documented coronary disease.8Hertzer NR. Basic data concerning associated coronary disease in peripheral vascular patients.Ann Vasc Surg. 1987; 1: 616-620Abstract Full Text PDF PubMed Scopus (149) Google Scholar Cumulative analysis of 4642 patients reported in six large series found the perioperative cardiac event (myocardial infarction, ischemia, arrhythmia, or congestive heart failure) rate to average 1.7% in patients without versus 11% in patients with clinically evident coronary disease, respectively.8Hertzer NR. Basic data concerning associated coronary disease in peripheral vascular patients.Ann Vasc Surg. 1987; 1: 616-620Abstract Full Text PDF PubMed Scopus (149) Google Scholar Late mortality in patients with clinically evident coronary disease was 44%, in contrast to the 22% mortality in patients without suspected coronary disease.8Hertzer NR. Basic data concerning associated coronary disease in peripheral vascular patients.Ann Vasc Surg. 1987; 1: 616-620Abstract Full Text PDF PubMed Scopus (149) Google Scholar Given the documented impact of ischemic heart disease on the mortality and morbidity associated with AAA repair, it is imperative that the potentially high risk cardiac patient be identified before operation. McEnroe et al.1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar investigate the utility of the cardiac risk index derived by Goldman et al.9Goldman L Caldera DL Nussbaum SR et al.Multifactorial index of cardiac risk in noncardiac surgical procedures.N Engl J Med. 1977; 297: 845-850Crossref PubMed Scopus (2072) Google Scholar for cardiac risk stratification before elective AAA repair. No correlation was found between this risk index classification and perioperative cardiac events, need for preoperative revascularization, or myocardial ischemia demonstrated by DTS. Are these results surprising? It must be remembered that the Goldman cardiac risk index was derived from a general surgical patient population among whom only 16.2% of patients underwent aortic or peripheral vascular surgery.9Goldman L Caldera DL Nussbaum SR et al.Multifactorial index of cardiac risk in noncardiac surgical procedures.N Engl J Med. 1977; 297: 845-850Crossref PubMed Scopus (2072) Google Scholar A history of angina pectoris or myocardial infarction was present in only 7% of patients, and only 27% of the entire population had any evidence of ischemic heart disease on clinical grounds (including multiple quite indirect electrocardiographic and chest radiographic criteria). Although the Goldman cardiac risk index has been validated prospectively in a large series of patients undergoing general surgery,10Zeldin RA. Assessing cardiac risk in patients who undergo noncardiac surgical procedures.Can J Surg. 1984; 27: 402-404PubMed Google Scholar it has been shown by Jeffery et al.11Jeffrey CC Kunsman J Cullen DJ Brewster DC. A prospective evaluation of cardiac risk index.Anesthesiology. 1983; 58: 462-464Crossref PubMed Scopus (129) Google Scholar underestimate perioperative risk during elective abdominal aortic surgery. In this patient population with a much higher incidence of known coronary artery disease (44%) and prior myocardial infarction (32%), the perioperative cardiac morbidity and mortality was nearly 8% in class I patients,11Jeffrey CC Kunsman J Cullen DJ Brewster DC. A prospective evaluation of cardiac risk index.Anesthesiology. 1983; 58: 462-464Crossref PubMed Scopus (129) Google Scholar those predicted by the Goldman risk index to be at very low risk (0.9%) of having a cardiac event.9Goldman L Caldera DL Nussbaum SR et al.Multifactorial index of cardiac risk in noncardiac surgical procedures.N Engl J Med. 1977; 297: 845-850Crossref PubMed Scopus (2072) Google Scholar Because of the high prevalence of both clinically evident and occult coronary artery disease in patients operated for AAA, there is clearly a much higher “pretest probability” of a cardiac event, which could markedly reduce the predictive accuracy of the Goldman risk index. Quantitation of left ventricular ejection fraction by radionuclide angiography has been found by some investigators to be predictive of perioperative myocardial infarction and death in patients undergoing AAA repair.12Pasternack PF Imparato AM Bear G et al.The value of radionuclide angiography as a predictor of perioperative myocardial infarction in patients undergoing abdominal aortic aneurysm resection.J Vasc Surg. 1984; 1: 320-325PubMed Scopus (107) Google Scholar Although left ventricular ejection fraction was determined in only 62% of patients, no such correlation was observed by McEnroe et al.1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar In a larger series of patients undergoing symptom-limited exercise radionuclide angiography before vascular surgery,13Kopecky SL Gibbons RJ Hollier LH. Preoperative supine exercise radionuclide angiogram predicts perioperative cardiovascular events in vascular surgery.J Am Coll Cardiol. 1986; 7 ([Abstract]): 226AGoogle Scholar no correlation was found between left ventricular ejection fraction or regional wall motion abnormalities (either at rest or at peak exercise) and perioperative myocardial infarction or death. The only predictor of a cardiac event was the inability to exercise to an adequate peak work load (400 kg/m/min).13Kopecky SL Gibbons RJ Hollier LH. Preoperative supine exercise radionuclide angiogram predicts perioperative cardiovascular events in vascular surgery.J Am Coll Cardiol. 1986; 7 ([Abstract]): 226AGoogle Scholar This study and others that evaluated exercise radionuclide angiography before general noncardiac surgery emphasize the importance of the functional limitation caused by myocardial ischemia as opposed to resting left ventricular function alone in the prediction of perioperative cardiac outcome.13Kopecky SL Gibbons RJ Hollier LH. Preoperative supine exercise radionuclide angiogram predicts perioperative cardiovascular events in vascular surgery.J Am Coll Cardiol. 1986; 7 ([Abstract]): 226AGoogle Scholar, 14Gerson MC Hurst JM Hertzberg VS et al.Cardiac prognosis in noncardiac geriatric surgery.Ann Intern Med. 1985; 103: 832-837Crossref PubMed Scopus (141) Google Scholar Nonphysiologic stress testing by means of DTS offers an alternative evaluation of the patient unable to exercise because of vascular, orthopedic, neurologic, or other general medical limitations. As suggested by several prior series,15Boucher CA Brewster DC Darling RC Okada RD Strauss HW Pohost GM. Determination of cardiac risk by dipyridamole-thallium imaging before peripheral vascular surgery.N Engl J Med. 1985; 312: 389-394Crossref PubMed Scopus (559) Google Scholar, 16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar, 17Eagle KA Singer DE Brewster DC Darling RC Mulley AG Boucher CA. Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.JAMA. 1987; 257: 2185-2189Crossref PubMed Scopus (271) Google Scholar DTS in the study of McEnroe et al.1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar appears to be a significant advance in comparison with prior techniques of risk assessment before vascular surgery. McEnroe et al.1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar found a low (4%) incidence of perioperative cardiac events (unstable angina, myocardial infarction, or death) in patients with normal DTS results. A high negative predictive value (>95%) has been described by others.15Boucher CA Brewster DC Darling RC Okada RD Strauss HW Pohost GM. Determination of cardiac risk by dipyridamole-thallium imaging before peripheral vascular surgery.N Engl J Med. 1985; 312: 389-394Crossref PubMed Scopus (559) Google Scholar, 16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar, 17Eagle KA Singer DE Brewster DC Darling RC Mulley AG Boucher CA. Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.JAMA. 1987; 257: 2185-2189Crossref PubMed Scopus (271) Google Scholar Contrary to prior studies,15Boucher CA Brewster DC Darling RC Okada RD Strauss HW Pohost GM. Determination of cardiac risk by dipyridamole-thallium imaging before peripheral vascular surgery.N Engl J Med. 1985; 312: 389-394Crossref PubMed Scopus (559) Google Scholar, 16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar, 17Eagle KA Singer DE Brewster DC Darling RC Mulley AG Boucher CA. Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.JAMA. 1987; 257: 2185-2189Crossref PubMed Scopus (271) Google Scholar, 18Eagle KA Coley CM Newell JB et al.Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery.Ann Intern Med. 1989; 110: 859-866Crossref PubMed Scopus (628) Google Scholar the current study1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar reported an unusually high (47%) cardiac event rate in the subset of patients with fixed defects on DTS. The authors appropriately question the “fixed” nature of thallium-201 defects at 4-hour imaging and suggest that these may represent viable myocardium, which is subject to late redistribution (and hence ischemia, not infarction) when imaged at 18 to 72 hours after dipyridamole infusion. Unfortunately, angiographic data are incomplete and the status of the presumed infarct-related artery patency is not defined.1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar Other investigators,19Yang LD Berman DS Kiat H et al.The frequency of late reversibility in SPECT thallium-201 stress-redistribution studies.J Am Coll Cardiol. 1990; 15: 334-340Abstract Full Text PDF PubMed Scopus (102) Google Scholar using the more sensitive imaging method of single photon emission computed tomography,20Fintel DJ Links JM Brinker JA Frank TL Parker M Becker LC. Improved diagnostic performance of exercise thallium-201 single photon emission computed tomography over planar imaging in the diagnosis of coronary artery disease: a receiver operating characteristic analysis.J Am Coll Cardiol. 1989; 13: 600-612Abstract Full Text PDF PubMed Scopus (133) Google Scholar have found late reversibility in 53% of patients undergoing exercise thallium-201 scintigraphy. This is concordant with results of position emission tomography, in which viable myocardium has been detected in 47% of “fixed” defects on exercise thallium-201 scintigraphy.21Brunken RC Kottou S Nienaber CA et al.PET detection of viable tissue in myocardial segments with persistent defects at T1-201 SPECT.Radiology. 1989; 172: 65-73PubMed Google Scholar Since myocardial thallium-201 uptake is significantly greater and clearance correspondingly longer after dipyridamole infusion compared to exercise,22Ruddy TD Gill JB Finkelstein DM et al.Myocardial uptake and clearance of thallium-201 in normal subjects: comparison of dipyridamole-induced hyperemia with exercise stress.J Am Coll Cardiol. 1987; 10: 547-556Abstract Full Text PDF PubMed Scopus (18) Google Scholar it may be that even a higher proportion of patients undergoing DTS will exhibit late thallium-201 redistribution. Late imaging in DTS should be performed to evaluate a fixed thallium-201 defect if there is no clinical history of infarction or correlative findings for infarction by electrocardiography or regional wall motion analysis or both on noninvasive imaging. Of patients with redistribution on DTS, and excluding those with preoperative coronary revascularization, 27% of patients in the current study had an ischemic event,1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar entirely in agreement with prior observations.16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar, 17Eagle KA Singer DE Brewster DC Darling RC Mulley AG Boucher CA. Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.JAMA. 1987; 257: 2185-2189Crossref PubMed Scopus (271) Google Scholar, 18Eagle KA Coley CM Newell JB et al.Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery.Ann Intern Med. 1989; 110: 859-866Crossref PubMed Scopus (628) Google Scholar As noted by McEnroe et al.1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar and by others,16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar, 17Eagle KA Singer DE Brewster DC Darling RC Mulley AG Boucher CA. Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.JAMA. 1987; 257: 2185-2189Crossref PubMed Scopus (271) Google Scholar, 18Eagle KA Coley CM Newell JB et al.Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery.Ann Intern Med. 1989; 110: 859-866Crossref PubMed Scopus (628) Google Scholar it is not possible to derive a true positive predictive value of redistribution on DTS, because a subgroup of patients had preoperative interventions based on DTS results. If the eight patients with revascularization are excluded in the current study,1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar the specificity of redistribution on DTS for a perioperative ischemic event (44 true negatives, 19 false positives) would be 70%. Other investigators have noted a similar specificity, and by stepwise logistic regression analysis found the predictive probability of a postoperative cardiac event (when redistribution is present on DTS) to be 33% ± 7%.16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar The high negative predictive value of DTS without redistribution,1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar, 15Boucher CA Brewster DC Darling RC Okada RD Strauss HW Pohost GM. Determination of cardiac risk by dipyridamole-thallium imaging before peripheral vascular surgery.N Engl J Med. 1985; 312: 389-394Crossref PubMed Scopus (559) Google Scholar, 16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar, 17Eagle KA Singer DE Brewster DC Darling RC Mulley AG Boucher CA. Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.JAMA. 1987; 257: 2185-2189Crossref PubMed Scopus (271) Google Scholar, 18Eagle KA Coley CM Newell JB et al.Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery.Ann Intern Med. 1989; 110: 859-866Crossref PubMed Scopus (628) Google Scholar even in the presence of a fixed defect,15Boucher CA Brewster DC Darling RC Okada RD Strauss HW Pohost GM. Determination of cardiac risk by dipyridamole-thallium imaging before peripheral vascular surgery.N Engl J Med. 1985; 312: 389-394Crossref PubMed Scopus (559) Google Scholar, 16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar, 17Eagle KA Singer DE Brewster DC Darling RC Mulley AG Boucher CA. Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.JAMA. 1987; 257: 2185-2189Crossref PubMed Scopus (271) Google Scholar essentially assures an acceptably low probability of a postoperative cardiac event. However, the clinician is often faced with the dilemma of how to pursue a DTS positive for redistribution, realizing that most of these patients (approximately 60% to 70%) will have an uncomplicated postoperative course without further investigation or intervention. The degree of DTS positivity may direct further evaluation. Although earlier studies found no correlation between the number of redistribution defects on DTS and cardiac events,16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar, 17Eagle KA Singer DE Brewster DC Darling RC Mulley AG Boucher CA. Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.JAMA. 1987; 257: 2185-2189Crossref PubMed Scopus (271) Google Scholar in a recent study23Lette J Waters D Lapointe J et al.Usefulness of the severity and extent of reversible perfusion defects during thallium-dipyridamole imaging for cardiac risk assessment before non-cardiac surgery.Am J Cardiol. 1989; 64: 276-281Abstract Full Text PDF PubMed Scopus (68) Google Scholar quantification of both the extent and severity of DTS redistribution was of great value in identifying patients at high risk for a perioperative cardiac event. These investigators found that 89% of “hard” cardiac events (myocardial infarction or death) occurred in patients with high-risk scintigraphic indexes of redistribution on DTS, regardless of the distribution of involved coronary arteries.23Lette J Waters D Lapointe J et al.Usefulness of the severity and extent of reversible perfusion defects during thallium-dipyridamole imaging for cardiac risk assessment before non-cardiac surgery.Am J Cardiol. 1989; 64: 276-281Abstract Full Text PDF PubMed Scopus (68) Google Scholar This method awaits prospective validation. Additional events occurring during dipyridamole infusion, such as ischemic chest discomfort and ischemic electrocardiographic changes may further increase the predictive value of redistribution on DTS.16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar, 18Eagle KA Coley CM Newell JB et al.Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery.Ann Intern Med. 1989; 110: 859-866Crossref PubMed Scopus (628) Google Scholar Eagle et al.17Eagle KA Singer DE Brewster DC Darling RC Mulley AG Boucher CA. Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.JAMA. 1987; 257: 2185-2189Crossref PubMed Scopus (271) Google Scholar, 18Eagle KA Coley CM Newell JB et al.Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery.Ann Intern Med. 1989; 110: 859-866Crossref PubMed Scopus (628) Google Scholar have shown that the value of DTS before vascular surgery is enhanced if used in conjunction with several clinical risk variables. In a series of 200 patients (69% undergoing AAA repair or aortoiliac bypass grafting), clinical predictors of postoperative ischemic events on multivariate logistic regression analysis were found to be history of angina, Q waves on the electrocardiogram, age >70 years, ventricular ectopy requiring medical therapy, and diabetes mellitus; clinical evidence of left ventricular failure was a univariate predictor.18Eagle KA Coley CM Newell JB et al.Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery.Ann Intern Med. 1989; 110: 859-866Crossref PubMed Scopus (628) Google Scholar Those patients with none of the above clinical variables had a 3% incidence of events, versus a 50% incidence in patients with ≥3 clinical risk variables, regardless of DTS results. Testing with DTS was most helpful in the stratification of patients at intermediate risk (one or two clinical variables), who comprized most of this patient population. Patients without redistribution on DTS had a low risk (3%), similar to patients without clinical risk factors, but the risk of a postoperative event increased 10-fold (30%) in patients with redistribution.18Eagle KA Coley CM Newell JB et al.Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery.Ann Intern Med. 1989; 110: 859-866Crossref PubMed Scopus (628) Google Scholar Should DTS or other forms of stress testing be used routinely for preoperative evaluation before AAA repair? In relatively young patients without symptoms and clinical risk factors as described by Eagle et al.,18Eagle KA Coley CM Newell JB et al.Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery.Ann Intern Med. 1989; 110: 859-866Crossref PubMed Scopus (628) Google Scholar the anticipated cardiac event rate will be <5%, which probably does not justify mandatory DTS screening in all such patients.24Eagle KA Boucher CA. Cardiac risk of noncardiac surgery.N Engl J Med. 1989; 321 ([Editorial]): 1330-1332Crossref PubMed Scopus (45) Google Scholar Nonetheless, the powerful impact of coronary disease on long-term prognosis after AAA repair (especially in younger patients5Reigel MM Hollier LH Kazmier FJ et al.Late survival in abdominal aortic aneurysm patients: the role of selective myocardial revascularization on the basis of clinical symptoms.J Vasc Surg. 1987; 5: 222-227PubMed Scopus (121) Google Scholar) does warrant stress testing at some time and at regular intervals during follow-up. In patients with clinically manifest but stable ischemic heart disease, stress testing (with or without DTS) is appropriate not only for the preoperative, but also long-term cardiac risk assessment after AAA repair. This approach will most likely benefit “younger” patients in the sixth and seventh decades of life.5Reigel MM Hollier LH Kazmier FJ et al.Late survival in abdominal aortic aneurysm patients: the role of selective myocardial revascularization on the basis of clinical symptoms.J Vasc Surg. 1987; 5: 222-227PubMed Scopus (121) Google Scholar Uncorrected, clinically evident coronary disease has been shown to increase the risk of death twofold, and risk of nonfatal cardiac events fourfold on long-term follow-up.7Roger VL Ballard DJ Hallett Jr, JW Osmundson PJ Puetz PA Gersh BJ. Influence of coronary artery disease on morbidity and mortality after abdominal aortic aneurysmectomy: a population-based study, 1971-1987.J Am Coll Cardiol. 1989; 14: 1245-1252Abstract Full Text PDF PubMed Scopus (155) Google Scholar Patients with significant (New York Heart Association functional class III or IV) ischemic symptoms, especially with recent (≤6 months) myocardial infarction or concomitant left ventricular failure, are candidates for coronary angiography with anticipation of coronary revascularization. Testing with DTS in this subset of patients at high risk for cardiac disease will not offer further risk stratification and may be hazardous. A protective effect of coronary artery bypass surgery before noncardiac surgery has been suggested by some investigators,25Mahar LJ Steen PA Tinker JH Vlietstra RE Smith HC Pluth JR. Perioperative myocardial infarction in patients with coronary artery disease with and without aorta-coronary artery bypass grafts.J Thorac Cardiovasc Surg. 1978; 76: 533-537PubMed Google Scholar, 26Hertzer NR Beven EG Young JR et al.Coronary artery disease in peripheral vascular patients. A classification of 1000 coronary angiograms and results of surgical management.Ann Surg. 1984; 199: 223-233Crossref PubMed Scopus (1196) Google Scholar but these were uncontrolled and nonrandomized observations, undoubtedly influenced by physician selection bias. The operative mortality of AAA repair in patients with prior coronary bypass grafting is similar to that in patients without evident coronary disease (generally <2%),8Hertzer NR. Basic data concerning associated coronary disease in peripheral vascular patients.Ann Vasc Surg. 1987; 1: 616-620Abstract Full Text PDF PubMed Scopus (149) Google Scholar but the potential benefit of coronary bypass surgery comes at a price. In the Coronary Artery Surgery Study the overall perioperative mortality of elective coronary bypass surgery in patients over the age of 65 years was 5.2%; 4.6% in patients 65 to 69 years old, 6.6% in patients 70 to 74 years old, and 9.5% in patients 75 years old and older.27Gersh BJ Kronmal RA Schaff HV et al.Long-term (5-year) results of coronary bypass surgery in patients 65 years old or older: a report from the Coronary Artery Surgery Study.Circulation. 1983; 68: II-190-II-199Google Scholar Improved mortality rates for coronary artery bypass surgery have been recently reported from the Cleveland Clinic, 0.7% in patients less than 65 years old, 2.0% in patients 65 to 74 years old, and 4.7% in patients 75 years old or older.28Loop FL Lytle BW Cosgrove DM et al.Coronary artery bypass graft surgery in the elderly. Indications and outcome.Cleve Clin J Med. 1988; 55: 23-34Crossref PubMed Scopus (118) Google Scholar On the other hand, in a small group of patients with peripheral vascular disease, coronary bypass grafting has been suggested by one randomized study to prolong long-term (5-year) survival in comparison with medical treatment.29Varnauskas E the European Coronary Surgery Study Group Twelve-year follow-up of survival in the randomized European Coronary Surgery Study.N Engl J Med. 1988; 319: 332-337Crossref PubMed Scopus (623) Google Scholar This is likely a reflection of the beneficial effects of revascularization on sicker patients and may be a marker of such preselected patients in other studies.1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar, 2Young JR Hertzer NR Beven EG et al.Coronary artery disease in patients with aortic aneurysm: a classification of 302 coronary angiograms and results of surgical management.Ann Vasc Surg. 1986; 1: 36-42PubMed Google Scholar, 16Leppo J Plaja J Gionet M Tumolo J Paraskos JA Cutler BS. Noninvasive evaluation of cardiac risk before elective vascular surgery.J Am Coll Cardiol. 1987; 9: 269-276Abstract Full Text PDF PubMed Scopus (261) Google Scholar, 17Eagle KA Singer DE Brewster DC Darling RC Mulley AG Boucher CA. Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.JAMA. 1987; 257: 2185-2189Crossref PubMed Scopus (271) Google Scholar, 18Eagle KA Coley CM Newell JB et al.Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery.Ann Intern Med. 1989; 110: 859-866Crossref PubMed Scopus (628) Google Scholar, 24Eagle KA Boucher CA. Cardiac risk of noncardiac surgery.N Engl J Med. 1989; 321 ([Editorial]): 1330-1332Crossref PubMed Scopus (45) Google Scholar, 25Mahar LJ Steen PA Tinker JH Vlietstra RE Smith HC Pluth JR. Perioperative myocardial infarction in patients with coronary artery disease with and without aorta-coronary artery bypass grafts.J Thorac Cardiovasc Surg. 1978; 76: 533-537PubMed Google Scholar Delaying AAA repair in favor of coronary artery bypass surgery is not entirely without risk, because some asymptomatic AAAs may rupture in the interim.2Young JR Hertzer NR Beven EG et al.Coronary artery disease in patients with aortic aneurysm: a classification of 302 coronary angiograms and results of surgical management.Ann Vasc Surg. 1986; 1: 36-42PubMed Google Scholar, 30Brown OW Hollier LH Pairolero PC Kazmier FJ McCready RA. Abdominal aortic aneurysm and coronary artery disease: a reassessment.Arch Surg. 1981; 116 (Discussion by Crawford ES): 1484-1488Crossref PubMed Google Scholar Percutaneous transluminal coronary angioplasty (PTCA) is an attractive alternative to coronary bypass surgery for preoperative revascularization. However, the attendant risks of PTCA must still be considered, and as reported in a recent multicenter study31Detre K Holubkov R Kelsey S et al.Percutaneous transluminal coronary angioplasty in 1985-1986 and 1977-1981. The National Heart, Lung, and Blood Institute Registry.N Engl J Med. 1988; 318: 265-270Crossref PubMed Scopus (645) Google Scholar these include nonfatal myocardial infarction (4.3%), need for emergency coronary artery bypass surgery (3.4%), and death (1.0%).31Detre K Holubkov R Kelsey S et al.Percutaneous transluminal coronary angioplasty in 1985-1986 and 1977-1981. The National Heart, Lung, and Blood Institute Registry.N Engl J Med. 1988; 318: 265-270Crossref PubMed Scopus (645) Google Scholar The proportion of patients with peripheral vascular disease and diffuse coronary disease who are suitable candidates for PTCA is unestablished. In the patient who is viable, middle-aged, and has AAA with stable symptomatic coronary artery disease, an aggressive approach is warranted with preoperative stress testing, and if significantly positive, coronary angiography. In the elderly patient with multiple other medical problems and limited life expectancy, conservative but optimized medical management of ischemic heart disease may be best. The perioperative cardiac mortality and morbidity for noncardiac surgery has apparently declined with the continuing advances in the practice of anesthesiology and with contemporary use of cardiac medications, hemodynamic monitoring, and close postoperative intensive care unit observation.32Rao TLK Jacobs KH El-Etr AA. Reinfarction following anesthesia in patients with myocardial infarction.Anesthesiology. 1983; 59: 499-505Crossref PubMed Scopus (453) Google Scholar Routine hemodynamic monitoring was used in the study by McEnroe et al.1McEnroe CS O'Donnell Jr, TF Yeager A Konstam M Mackey WC. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery.J Vasc Surg. 1990; 11: 497-504PubMed Scopus (119) Google Scholar and may well have contributed to the relatively low (2.1%) perioperative mortality observed in this series of elective AAA repairs. With the improving sophistication in preoperative and perioperative management, the mortality of AAA repair in even high-risk patients has been shown to be 5.7%.33Hollier LH Riegel MM Kazmier FJ Pairolero PC Cherry KJ Hallett Jr., JW Conventional repair of abdominal aortic aneurysm in the high risk patient: a plea for abandonment of nonresective treatment.J Vasc Surg. 1986; 3: 712-717PubMed Scopus (63) Google Scholar Intraoperative intraaortic balloon counter-pulsation may be useful in the patient at extremely high cardiac risk.33Hollier LH Riegel MM Kazmier FJ Pairolero PC Cherry KJ Hallett Jr., JW Conventional repair of abdominal aortic aneurysm in the high risk patient: a plea for abandonment of nonresective treatment.J Vasc Surg. 1986; 3: 712-717PubMed Scopus (63) Google Scholar Decisions regarding major preoperative cardiac intervention, for example coronary revascularization before elective AAA repair, are best guided by careful clinical judgment. The potential risks versus benefits must be carefully weighed for the individual patient. Preoperative electrocardiographic monitoring for myocardial ischemia34Raby KE Goldman L Creager MA et al.Correlation between preoperative ischemia and major cardiac events after peripheral vascular surgery.N Engl J Med. 1989; 321: 1296-1300Crossref PubMed Scopus (315) Google Scholar or dipyridamole-echocardiography35Picano E Severi S Michelassi C et al.Prognostic importance of dipyridamole-echocardiography test in coronary artery disease.Circulation. 1989; 80: 450-457Crossref PubMed Scopus (124) Google Scholar may be alternatives to DTS in patients unable to perform standard exercise stress testing. Careful clinical evaluation, judicious preoperative testing, appropriate cardiac intervention, and meticulous perioperative care will ideally minimize cardiac morbidity and mortality associated with AAA repair.