PERIOPERATIVE CARDIAC COMPLICATIONS are a

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1 Revised Cardiac Risk Index (Lee) and Perioperative Cardiac Events as Predictors of Long-term Mortality in Patients Undergoing Endovascular Abdominal Aortic Aneurysm Repair Sylvia Archan, MD,* Christopher R. Roscher, MD,* Ronald M. Fairman, MD, and Lee A. Fleisher, MD* Objective: To determine if the Revised Cardiac Risk Index (Lee) is useful for stratification of patients by risk of both perioperative cardiac morbidity and long-term all-cause mortality in the setting of endovascular repair of abdominal aortic aneurysms. Design: This study was designed as a retrospective review. Setting: It was conducted at a single academic medical institution. Participants: The analysis included 225 patients with abdominal aortic aneurysms admitted to the authors institution from 1999 to Interventions: All patients underwent endovascular aortic aneurysm repair. Measurements and Main Results: Data were collected from medical records, office charts, and physician qualityassurance databases. There were no in-hospital cardiac deaths. The major adverse cardiac event rate in the perioperative period was 6.2%. Long-term all-cause mortality was 23%. Univariate analysis showed that a history of coronary artery disease (CAD) (likelihood ratio [LR] 8.7, p 0.023), history of congestive heart failure (LR 4, p 0.042), and a PERIOPERATIVE CARDIAC COMPLICATIONS are a major cause for morbidity and mortality in patients with multiple cardiac risk factors undergoing abdominal aortic aneurysm repair. The incidence of perioperative myocardial ischemic injury in patients undergoing vascular surgery may be as high as 18% to 35% in the highest-risk patients. 1-3 Furthermore, a perioperative myocardial infarction after a noncardiac operation is associated with an increased risk of death. 4-7 In the past decade, endovascular abdominal aortic aneurysm repair (EAAAR) has evolved as an alternative to the traditional open surgical approach. A number of trials have shown substantial reductions in perioperative mortality and morbidity with endovascular repair of abdominal aortic aneurysm as compared with open surgical repair Schouten et al 12 showed that, even in patients at high risk, endovascular treatment reduces the incidence of perioperative myocardial complications as compared with open repair. Although the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial and the Endovascular Aneurysm Repair (EVAR)-1 trial From the Departments of *Anesthesiology and Critical Care and Surgery, Division of Vascular Surgery, University of Pennsylvania, Philadelphia, PA; and Department of Anesthesiology and Critical Care, Medical University of Graz, Graz, Austria. Address reprint requests to Sylvia Archan, MD, Department of Anesthesiology and Critical Care, Hospital of the Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria. sylvia. archan@medunigraz.at 2010 Elsevier Inc. All rights reserved /10/ $36.00/0 doi: /j.jvca Revised Cardiac Risk Index (RCRI) >3 (LR 8.6, p 0.004) were significant predictors for perioperative major adverse cardiac events. A history of CAD (LR 10.7, p 0.002), echocardiographic evidence of myocardial infarction (LR 8.5, p 0.006), exercise tolerance of only 1 block (LR 8.4, p 0.005), RCRI >3 (LR 5.6, p 0.022), and perioperative cardiac events (LR 15.9, p < ) were significantly associated with long-term all-cause mortality. Perioperative cardiac events remained highly significant in predicting long-term mortality within the RCRI >3 subgroup (LR 6.1, p 0.019). Conclusions: The results of this study confirm that longterm mortality remains high after endovascular repair of abdominal aortic aneurysms. The Lee index may be a useful tool for stratification of high-risk patients from both a shortand long-term perspective in the setting of endoluminal graft repair Elsevier Inc. All rights reserved. KEY WORDS: endovascular repair, abdominal aortic aneurysms, long-term mortality, perioperative cardiac events, predictors showed a perioperative benefit for patients treated endovascularly, both trials failed to show a benefit in overall survival after a median follow-up of 1.8 and 2.9 years, respectively. Importantly, the EVAR-2 trial results indicate that high-risk patients deemed unfit for open surgical repair who undergo endovascular repair have the same rate of cardiovascular-related deaths as patients randomized to no repair of their aneurysm during a median follow-up of 2.4 years. 13 It has been argued that open abdominal aneurysm repair might be considered the ultimate cardiac stress test. If a patient survives the operation, the overall cardiac prognosis might not be that bad. 12 This selection by survival of the fittest does not as readily occur in patients who undergo endovascular repair, and adverse cardiac events remain a major source of long-term morbidity and mortality after EAAAR. Although several risk-scoring systems have been derived for patients undergoing open aortic repair, these appear to lack accuracy when applied to EAAAR patients Only Baas et al 18 were able to show that the Glasgow Aneurysm Score (GAS) is a good predictor of 30-day and 2-year mortality in the patients from the DREAM trial. Aziz et al 19 identified age 70 years or older, history of myocardial infarction (MI) or congestive heart failure (CHF), and lack of use of preoperative -blocker therapy as independent risk factors for perioperative cardiac events in patients undergoing EAAAR. De Virgilio et al 20 were the first to show that preoperative clinical cardiac risk factors are also significant predictors of long-term mortality after endovascular repair of abdominal aortic aneurysms. To the best of the authors knowledge, this is the first attempt at applying the Revised Cardiac Risk Index (RCRI) to patients undergoing EAAAR for prediction of perioperative major adverse cardiac events (MACEs) as well as long-term all-cause mortality. 84 Journal of Cardiothoracic and Vascular Anesthesia, Vol 24, No 1 (February), 2010: pp 84-90

2 REVISED CARDIAC RISK INDEX 85 METHODS After obtaining institutional review board approval, a single reviewer (C.R.R.) collected data from the medical records, office charts, and physician quality-assurance databases of a single surgeon s consecutive series of patients admitted to a single academic institution for endovascular aortic aneurysm repair from 1999 to Patients who had emergent placement of endovascular aortic stents, patients who had non Food and Drug Administration approved stents placed, and patients who received Ancure (Endovascular Technologies, Menlo Park, CA) stents were excluded from the study. The latter group of patients was excluded because the Ancure stent has since been removed from the market. The collected data included all preoperative demographics and risk factors as outlined by the American Heart Association/American College of Cardiology guidelines 21 as well as the Lee Revised Cardiac Risk Index score, the Glasgow Aneurysm Risk score, and documentation on perioperative cardiovascular medication use. Longterm mortality was assessed searching public records by using Social Security numbers. The primary endpoints were in-hospital MACEs, as defined by cardiac death (medical records, electrocardiogram [ECG] findings, and elevated cardiac enzymes consistent with a fatal myocardial infarction), non-fatal myocardial infarction (ECG findings consistent with infarction and/or elevated cardiac enzymes), unstable angina (new or increased chest pain with ECG changes consistent with ischemia), new onset or worsening of CHF (clinical examination or chest radiograph consistent with heart failure and/or elevated brain natriuretic peptide), or coronary revascularization at any time during hospitalization, as documented in the medical records. A secondary endpoint was all-cause mortality during the follow-up period. All statistical analyses were performed by using JMP version software (SAS Institute, Cary, NC). Continuous data are presented as mean values, whereas dichotomous data are presented as percentages. Univariate analyses of likelihood ratios and odds ratios for perioperative MACEs, death at 1 year, death at 2 years, and death by end of follow-up were calculated by using chi-square tests or Fisher exact tests, as appropriate. Receiver-operating characteristic (ROC) curves were generated for GAS and RCRI for perioperative MACE and death at 1 year, respectively. For predictive ability, an area under the curve (AUC) of 0.5 is recognized as no better than chance, 0.6 to 0.7 as poor, 0.7 to 0.8 as fair, 0.8 to 0.9 as good, and 0.9 to 1.0 as excellent. 22 A modified Lee index for prediction of long-term all-cause mortality was created by adding 1 to the preoperative score if a perioperative MACE had occurred and ROC curves were generated for this modified Lee index as well. RESULTS Table 1. Selected Patient Characteristics No.* % Age 73.8 (SD 9) Male 193 (225) 85.8 White Black Hypertension Diabetes mellitus (total) Tobacco (total) History of CAD Any angina CCVS I CCVS II CCVS III CCVS IV History or echo evidence of MI History of arrhythmia Pacemaker Positive stress result (total number of patients with any stress test result available) 45 (195) 23.1 LM 50% 6 (49) 12.2 LAD 70% 18 (49) 36.7 LCX 70% 14 (49) 28.6 RCA 70% (total number of patients with cardiac catheterization result available) 24 (49) 49.0 PCI 36 (225) 16.0 CABG History of COPD History of CHF History of CVA Exercise tolerance 1 block 38 (216) 17.6 Exercise tolerance 2 blocks 34 (216) 15.7 Exercise tolerance 2 blocks (total number of patients with information on exercise tolerance available) 143 (216) 66.2 Aspirin Clopidogrel Blockers Statins ACEI/ARB Nitrates Abbreviations: CCVS, Canadian Cardiovascular Society Angina; LM, left main coronary artery; LAD, left anterior descending coronary artery; LCX, left circumflex coronary artery; RCA, right coronary artery; PCI, percutaneous coronary intervention; CABG, coronary artery bypass graft; COPD, chronic obstructive pulmonary disease; ACEI, angiotensin-converting enzyme inhibitors; ARB, angiotensin II receptor blockers. *If not otherwise indicated, numbers in parentheses are denominator. After excluding patients as described under the Methods section, a total of 225 subjects were reviewed (Table 1); 85.8% were males, more than 90% were white, and the prevalence of significant medical comorbidities, including hypertension (85.3%), history of tobacco use (82.2% either past or current), and CAD (74.2%), were considerably higher in comparison to other studies. 8,10-13,23 Ninety-seven patients had 1, 78 patients had 2, and 50 patients had 3 or more RCRI factors. The average age of the participants was 73.8 years (standard deviation 9); 52.4% were on -blockers preoperatively, 50.5% were statin users; 33.6% experienced perioperative statin discontinuation and only 8.4% -blocker withdrawal, defined as more than 48 hours before statin/ -blocker administration was resumed postoperatively. Patient follow-up was complete up to October 2006, and the median length of follow-up was 759 days. With respect to the primary endpoint, there were no inhospital cardiac deaths; 10 nonfatal MIs (4.4%), 9 of which were non-st elevation MIs; and only 1 ST-elevation myocardial infarction (STEMI). Seven patients sustained a new onset or worsening of CHF during hospitalization (3.1%), and 4 patients had unstable angina (1.8%). All patients with unstable angina also had a myocardial infarction, and 3 patients with AMI (non-stemi) also had CHF. In total, 14 patients (6.2%) suffered at least 1 MACE in the perioperative period. There were no coronary revascularization procedures. The number of patients reaching the primary endpoint based on the number of RCRI factors was distributed as follows: among patients with 1

3 86 ARCHAN ET AL RCRI factor 2 (2.1%), 2 RCRI factors 4 (5.1%), and 3 or more RCRI factors 8 (16%). Univariate analysis showed that a history of CAD (LR 8.7, p 0.023), a history of CHF (LR 4, p 0.042), and an RCRI 3 (LR 8.6, p 0.004) were predictors of postoperative MACEs (Table 2). The ROC curve analysis for RCRI score revealed an AUC of 0.73 for predicting postoperative cardiac events. The AUCs for the prediction of postoperative cardiac events by age and GAS were 0.60 and 0.67, respectively. Of note, 3 patients (1.3%) died in the perioperative period, 1 patient suffered rupture and death in the operating room before the beginning of the operation and 2 patients died in the intensive care unit from primary pulmonary causes (Figs 1 and 2). With respect to the secondary endpoint, 52 patients (23%) died during follow-up with an average length of survival of 672 days (standard deviation 571). Of the patients who suffered a perioperative MACE, 5 died within 1 year; 6 within 2 years; and, by the end of follow-up, 10 (71.4%) had died. Of the patients without a MACE in the perioperative period, 13 died within 1 year; 25 within 2 years; and, by the end of follow-up, 42 (19.9%) had died (Fig 3). The incidence of secondary outcomes based on RCRI class was as follows: among patients with 1 RCRI factor 17 (17.5%), 2 RCRI factors 17 (21.8%), and 3 or more RCRI factors 18 (36%). Univariate analysis showed that an RCRI 3 (LR 14, p ), echocardiographic evidence of MI (LR 12.4, p ), history of CAD (LR 5.5, p 0.048), history of CHF (LR 8, p 0.005), Table 2. Univariate Analysis for Perioperative MACEs Hx of CAD * * CCVS class IV * * Stated history of MI MI Positive stress result CAD) Hx of CHF Hx of severe valvular disease Exercise tolerance of 1 block Statins preoperatively factor BB preoperatively BB withdrawal (denominator preoperatively on BB) Statin discontinuation (denominator preoperatively on statins) Lee Index Hx of COPD Tobacco use Cardiovascular Society; CABG, coronary artery bypass graft; ACC/ AHA, American College of Cardiology/American Heart Association; COPD, chronic obstructive pulmonary disease. *Not computable because the number of patients with a history of CAD/CCVS class IV who did not have an event equals 0. Fig 1. Long-term survival after EAAAR. (Color version of figure is available online.) exercise tolerance of only 1 block (LR 5.7, p 0.015), and perioperative MACE (LR 9.6, p 0.002) were predictors of 1-year mortality (Table 3). The ROC curve analysis for the RCRI score revealed an AUC of 0.72 for predicting death at 1 year, and the calculated AUC for the modified RCRI score in which the authors simply added 1 for those patients who sustained 1 or more postoperative cardiac events was For death at 2 years, only echocardiographic evidence of MI (LR 11.3, p ), exercise tolerance of only 1 block (LR 8, p 0.007), history of CAD (LR 5.8, p 0.027), and perioperative MACE (LR 7.7, p 0.006) remained highly significant predictors (Table 4). A history of CAD (LR 10.7, p 0.002), echocardiographic evidence of MI (LR 8.5, p 0.006), exercise tolerance of only 1 block (LR 8.4, p 0.005), RCRI 3 (LR 5.6, p 0.022), and perioperative cardiac events (LR 15.9, p ) were significantly associated with long-term all-cause mortality (Table 5). What is remarkable is that MACEs remained highly significant in predicting mortality within the RCRI 3 subgroup (LR 6.1, p 0.019), Fig 2. Kaplan-Meier survival curves showing the difference in survival between patients with 1 or 2 versus 3 or more Lee Risk Index predictors (p 0.005). (Color version of figure is available online.)

4 REVISED CARDIAC RISK INDEX 87 Fig 3. Kaplan-Meier survival curves showing the difference in survival between patients who suffered a postoperative major adverse cardiac event versus event-free patients (p < ). (Color version of figure is available online.) indicating that MACEs allow further risk stratification even among the highest-risk patients (Fig 4). DISCUSSION With progressive reduction of in-hospital mortality, the assessment of patient longevity after abdominal aortic aneurysm repair is an important factor in clinical decision-making with regard to the choice of procedure as well as for the optimization of medical therapy. Preoperative risk assessment of patients undergoing major noncardiac surgery has been designed to identify patients at increased risk for perioperative mortality and morbidity. However, there is a strong relationship between perioperative cardiac and noncardiac complications and subsequent mortality; almost half of the patients who experience cardiac morbidity develop other types of noncardiac complications and mortality. 24 Clinical cardiac risk factors have been found to be useful predictors of perioperative cardiac events after numerous types of vascular procedures. 19,25,26 The Lee index, which was derived from a dataset of 4,315 patients undergoing noncardiac surgery on the basis of the original Goldman index, is now considered by many clinicians and researchers to be the most relevant index to predict cardiac risk. 27 The fact that the ACC/AHA Committee incorporated the RCRI in the 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery further emphasizes its significance. 21 Boersma et al 28 adapted the Lee index for prediction of cardiovascular mortality in 108,593 patients who underwent noncardiac surgery in the Erasmus Medical Center from 1991 to By adding age and more detailed information regarding the type of surgery, they were able to increase the AUC for the prediction of cardiovascular mortality using the Lee index from 0.63 to In the present series of 225 patients undergoing EAAAR, the authors found the following factors associated with decreased long-term survival: echocardiographic evidence of MI, RCRI 3, exercise tolerance of only 1 block, and postoperative cardiac events. Endoluminal graft repair is a less invasive and less hemodynamically stressful technique than standard open repair and is thus intuitively appealing in patients at high risk. The less invasive nature of endoluminal graft repair would suggest that standard methods for cardiac risk stratification for open vascular surgery might not be applicable. Indeed, a number of risk indices originally developed for open repair were evaluated for EAAAR and generally found to be poor predictors Bohm et al 14 reported that the GAS, the Vascular Physiology and Operative Severity Score for the enumeration of Mortality and Morbidity, the modified Customized Probability Index, and the Customized Probability Index showed AUCs of 0.68, 0.66, 0.63, and 0.65 for prediction of 30-day mortality. Sajid et al 15 found that both the GAS and the Hardman Index overestimate mortality and morbidity after EAAAR in their small sample of 71 patients. After validating the GAS, the Modified Leiden Score, and the Modified Comorbidity Severity Score to their open repair dataset, Faizer et al 16 calculated C-statistics for the prediction of perioperative mortality in the EAAAR group. With AUCs of 0.47 (GAS), 0.70 (Modified Leiden Score), and 0.69 (Modified Comorbidity Severity Score), these stratification systems performed rather poorly. Biancari et al 17 reported Table 3. Univariate Analysis for Mortality at 1 Year Hx of CAD CCVS class IV Stated hx of MI MI Positive stress result CAD) Hx of CHF Hx of severe valvular disease Exercise tolerance 1 block Statins preoperatively Statin users (last hospital day), n factor BB users (last hospital day), n BB Withdrawal (denominator preoperatively on BB) Statin discontinuation (denominator preoperatively on statins) Lee Index Hx COPD Tobacco use MACE (whole dataset) MACE (denominator Lee 3) Lee Index 3 and MACE Cardiovascular Society; CABG, coronary artery bypass graft; BB, -blocker; ACC/AHA, American College of Cardiology/American Heart Association; COPD, chronic obstructive pulmonary disease.

5 88 ARCHAN ET AL an AUC of 0.70 for the prediction of postoperative death by GAS in patients from the EUROSTAR Registry. Baas et al 18 successfully applied the GAS as a tool for prediction of 30-day and 2-year mortality in the patients from the DREAM trial. Unfortunately, it proved most valuable in identifying low-risk patients but was not very useful for the identification of highrisk patients. In the present study, the authors found a highly significant association between a Lee index 3 and postoperative cardiac events (p 0.004) as well as 1-year mortality (p ) and long-term mortality (p 0.02). These results indicate that the Lee index, even if its overall discriminatory ability is fair at best, is a useful tool for the identification of high-risk patients from both a short- and long-term perspective. Although the Lee index was developed for the prediction of prospectively detected major cardiac complications and not for the prediction of (cardiovascular) death, it may be easier to predict the incidence of death than to predict a broader range of clinical outcomes. 29 The second major finding of this study was that a postoperative MACE was a highly significant predictor of mortality at 1 year (LR 9.6, p 0.002) as well as at 2 years (LR 7.7, p 0.006) and by the end of follow-up (LR 15.9, p ). Postoperative cardiac events proved that they had value Table 4. Univariate Analysis for Mortality at 2 Years Hx of CAD CCVS class IV Stated hx of MI MI Positive stress result CAD) Hx of CHF Hx of severe valvular disease Exercise tolerance 1 block Statin users (last hospital day), n factor BB users (last hospital day), n BB withdrawal (denominator preoperatively on BB) Statin discontinuation (denominator preoperatively on statins) Lee Index Hx of COPD Tobacco use MACE (whole dataset) MACE (denominator Lee 3) Lee Index 3 and MACE Cardiovascular Society; CABG, coronary artery bypass graft; BB, -blocker; ACC/AHA, American College of Cardiology/American Heart Association; COPD, chronic obstructive pulmonary disease. Table 5. Univariate Analysis for Mortality at End of Follow-up Hx of CAD CCVS class IV * * Stated hx of MI MI Positive stress result CAD) Hx CHF Hx severe valvular disease Exercise tolerance 1 block factor Lee Index Hx of COPD Tobacco use MACE (whole dataset) MACE (denominator Lee 3) Lee Index 3 and MACE Cardiovascular Society; CABG, coronary artery bypass graft; BB, -blocker; ACC/AHA, American College of Cardiology/American Heart Association; COPD, chronic obstructive pulmonary disease. *Not computable because the number of patients with CCVS class IV who survived equals 0. for risk stratification even among the highest-risk (RCRI 3) group of patients. In contrast to what was reported by de Virgilio et al, 20 the present data show that long-term survival is significantly impaired even after minor perioperative infarction, in line with what occurs found after acute coronary syndromes in nonsurgical patients and what was reported for the setting of major vascular surgery by Landesberg et al 30 and Bursi et al. 31 The fact that exercise tolerance of no more than 1 block was Fig 4. Kaplan-Meier survival curves showing the difference in survival between patients who suffered a postoperative major adverse cardiac event versus event-free patients in the subgroup with 3 or more Lee Risk Index predictors (p 0.027). (Color version of figure is available online.)

6 REVISED CARDIAC RISK INDEX 89 highly associated with long-term mortality in the present study reinforces the emphasis of functional capacity as a tool for risk stratification, as advocated in the ACC/AHA Guidelines. Importantly, using a lower cutoff of 1 block was able to discriminate risk even in a population with limited exercise capacity. One of the major limitations of the present study was that it was a retrospective review, and the authors could only determine mortality by death certificates. For this reason, the authors analyzed all-cause mortality rather than attempting to determine long-term cardiac mortality. Although the availability of such data would be highly desirable, numerous previous studies showed that the majority of deaths in vascular surgery patients are cardiac in nature and that nearly half of the other noncardiac causes of death are cardiovascular The authors were also limited in the number of factors that could be analyzed because of sample size. The authors institution actively participated in Food and Drug Administration approved phase I and pivotal stent graft trials in the late 1990s and early 2000s, and, therefore, more than half of the patients potentially meeting the inclusion criteria were being enrolled in studies that excluded them from the present study. In conclusion, the present results confirm that long-term mortality remains high after EAAAR. The Lee index may be useful for risk stratification in the setting of endoluminal graft repair. Once a patient develops a perioperative myocardial ischemic injury, further evaluation for CAD may be warranted. Whether more aggressive treatment of patients with postoperative cardiac events can improve survival needs to be further investigated. 1. Mackey WC, Fleisher LA, Haider S, et al: Perioperative myocardial ischemic injury in high-risk vascular surgery patients: Incidence and clinical significance in a prospective clinical trial. J Vasc Surg 43: , Poldermans D, Boersma E, Bax JJ, et al: The effect of bisoprolol on perioperative mortality and myocardial infarction in high-risk patients undergoing vascular surgery. Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography Study Group. N Engl J Med 341: , Raby KE, Barry J, Creager MA, et al: Detection and significance of intraoperative and postoperative myocardial ischemia in peripheral vascular surgery. JAMA 268: , Yeager RA, Moneta GL, Edwards JM, et al: Late survival after perioperative myocardial infarction complicating vascular surgery. J Vasc Surg 20: , Lopez-Jimenez F, Goldman L, Sacks DB, et al: Prognostic value of cardiac troponin T after noncardiac surgery: 6-month follow-up data. J Am Coll Cardiol 29: , McFalls EO, Ward HB, Santilli S, et al: The influence of perioperative myocardial infarction on long-term prognosis following elective vascular surgery. Chest 113: , Kim LJ, Martinez EA, Faraday N, et al: Cardiac troponin I predicts short-term mortality in vascular surgery patients. Circulation 106: , Cuypers PW, Gardien M, Buth J, et al: Randomized study comparing cardiac response in endovascular and open abdominal aortic aneurysm repair. Br J Surg 88: , Greenhalgh RM, Brown LC, Kwong GP, et al: Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial. Lancet 364: , Prinssen M, Verhoeven EL, Buth J, et al: A randomized trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med 351: , Schermerhorn ML, O Malley AJ, Jhaveri A, et al: Endovascular vs. open repair of abdominal aortic aneurysms in the Medicare population. N Engl J Med 358: , Schouten O, Dunkelgrun M, Feringa HH, et al: Myocardial damage in high-risk patients undergoing elective endovascular or open infrarenal abdominal aortic aneurysm repair. Eur J Vasc Endovasc Surg 33: , Endovascular aneurysm repair and outcome in patients unfit for open repair of abdominal aortic aneurysm (EVAR trial 2): Randomised controlled trial. Lancet 365: , Bohm N, Wales L, Dunckley M, et al: Objective risk-scoring systems for repair of abdominal aortic aneurysms: Applicability in endovascular repair? Eur J Vasc Endovasc Surg 36: , 2008 REFERENCES 15. Sajid MS, Tai N, Goli G, et al: Applicability of Glasgow Aneurysm Score and Hardman Index to elective endovascular abdominal aortic aneurysm repair. Asian J Surg 30: , Faizer R, DeRose G, Lawlor DK, et al: Objective scoring systems of medical risk: A clinical tool for selecting patients for open or endovascular abdominal aortic aneurysm repair. J Vasc Surg 45: , Biancari F, Hobo R, Juvonen T: Glasgow Aneurysm Score predicts survival after endovascular stenting of abdominal aortic aneurysm in patients from the EUROSTAR registry. Br J Surg 93: , Baas AF, Janssen KJ, Prinssen M, et al: The Glasgow Aneurysm Score as a tool to predict 30-day and 2-year mortality in the patients from the Dutch Randomized Endovascular Aneurysm Management trial. J Vasc Surg 47: , Aziz IN, Lee JT, Kopchok GE, et al: Cardiac risk stratification in patients undergoing endoluminal graft repair of abdominal aortic aneurysm: A single-institution experience with 365 patients. J Vasc Surg 38:56-60, de Virgilio C, Tran J, Lewis R, et al: Factors affecting long-term mortality after endovascular repair of abdominal aortic aneurysms. Arch Surg 141: , Fleisher LA, Beckman JA, Brown KA, et al: ACC/AHA 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery): Developed in Collaboration With the American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Rhythm Society, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, and Society for Vascular Surgery. Circulation 116: , Zweig MH, Campbell G: Receiver-operating characteristic (ROC) plots: A fundamental evaluation tool in clinical medicine. Clin Chem 39: , Endovascular aneurysm repair versus open repair in patients with abdominal aortic aneurysm (EVAR trial 1): Randomised controlled trial. Lancet 365: , Fleischmann KE, Goldman L, Young B, et al: Association between cardiac and noncardiac complications in patients undergoing noncardiac surgery: Outcomes and effects on length of stay. Am J Med 115: , Eagle KA, Cambria R, Coley C, et al: Assessment of cardiac risk before abdominal aortic surgery. N Engl J Med 331:480, 1994

7 90 ARCHAN ET AL 26. Eagle KA, Lauer MS: Preoperative evaluation before noncardiac vascular surgery. Cleve Clin J Med 63: , Lee TH, Marcantonio ER, Mangione CM, et al: Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation 100: , Boersma E, Kertai MD, Schouten O, et al: Perioperative cardiovascular mortality in noncardiac surgery: Validation of the Lee cardiac risk index. Am J Med 118: , Boersma E, Pieper KS, Steyerberg EW, et al: Predictors of outcome in patients with acute coronary syndromes without persistent ST-segment elevation. Results from an international trial of 9461 patients. The PURSUIT Investigators. Circulation 101: , Landesberg G, Shatz V, Akopnik I, et al: Association of cardiac troponin, CK-MB, and postoperative myocardial ischemia with longterm survival after major vascular surgery. J Am Coll Cardiol 42: , Bursi F, Babuin L, Barbieri A, et al: Vascular surgery patients: Perioperative and long-term risk according to the ACC/AHA guidelines, the additive role of post-operative troponin elevation. Eur Heart J 26: , Jamieson WR, Janusz MT, Miyagishima RT, et al: Influence of ischemic heart disease on early and late mortality after surgery for peripheral occlusive vascular disease. Circulation 66:I92-I97, Hertzer NR, Young JR, Beven EG, et al: Late results of coronary bypass in patients presenting with lower extremity ischemia: The Cleveland Clinic Study. Ann Vasc Surg 1: , L Italien GJ, Cambria RP, Cutler BS, et al: Comparative early and late cardiac morbidity among patients requiring different vascular surgery procedures. J Vasc Surg 21: , Norman PE, Semmens JB, Lawrence-Brown MM: Long-term relative survival following surgery for abdominal aortic aneurysm: A review. Cardiovasc Surg 9: , 2001