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Paper |

Endovascular vs Open Abdominal Aortic Aneurysm Repair:  A Comparison of Cardiac Morbidity and Mortality FREE

Christian de Virgilio, MD; Hao Bui, MD; Carlos Donayre, MD; Linda Ephraim, RN, BSN; Roger J. Lewis, MD, PhD; Magdi Elbassir, MD; Bruce E. Stabile, MD; Rodney White, MD
[+] Author Affiliations

From the Departments of Surgery (Drs de Virgilio, Bui, Donayre, Elbassir, Stabile, and White and Ms Ephraim) and Emergency Medicine (Dr Lewis), Harbor-UCLA Medical Center, Torrance, Calif; and the Department of Surgery, West Los Angeles Veteran Affairs Medical Center (Dr de Virgilio), Los Angeles, Calif.


Arch Surg. 1999;134(9):947-951. doi:10.1001/archsurg.134.9.947.
Text Size: A A A
Published online

Hypothesis  Adverse cardiac event rates following endovascular abdominal aortic aneurysm (EAAA) and open abdominal aortic aneurysm (OAAA) repair are similar. We also hypothesized that the Eagle criteria (Q wave on electrocardiogram, diabetes, angina, congestive heart failure, age >70 years, and ventricular ectopy) are useful predictors of cardiac events in patients undergoing EAAA repair.

Design  Prospective (patients undergoing EAAA repair) and retrospective (patients undergoing OAAA repair).

Setting  Public teaching and Veterans Affairs medical centers.

Patients  Eighty-three EAAA and 63 OAAA repairs.

Main Outcome Measures  Myocardial infarction, congestive heart failure, and cardiac death.

Results  Patients with EAAA were older (73 vs 68 years, P=.003). There were no differences in the mean number of Eagle criteria (1.2 vs 1.3), cardiac event rates (6% vs 4.8%), or mortalities (3.6% vs 4.8%). Within the EAAA group, congestive heart failure (P=.005) and Q wave on electrocardiogram (P=.006) were the only predictors of cardiac events.

Conclusions  Patients undergoing OAAA and EAAA repair had similar cardiac event rates and mortality. In patients undergoing EAAA repair, history of congestive heart failure and Q wave on electrocardiogram were predictors of cardiac events.

SINCE THE FIRST report by Parodi et al,1 interest in endovascular repair of abdominal aortic aneurysms (EAAA) has grown markedly. Multiple series have demonstrated the short-term effectiveness of EAAA repair.27 However, few data are available regarding the cardiac morbidity and mortality of EAAA repair as compared with standard open repair of abdominal aortic aneurysms (OAAA).

The Eagle criteria (aged >70 years, diabetes, angina, history of congestive heart failure [CHF], Q wave on electrocardiogram [ECG], and ventricular arrhythmia requiring therapy) have been shown to be predictive of adverse cardiac events following elective vascular surgery.810 However, the utility of these criteria for predicting adverse cardiac events in patients undergoing EAAA repair has not been investigated.

The purpose of this study was to compare cardiac morbidity and postoperative mortality for EAAA vs OAAA repair and to determine the predictive value of the Eagle criteria in patients undergoing EAAA repair.

Data for consecutive patients undergoing elective EAAA repair at Harbor-UCLA Medical Center (Torrance, Calif) and West Los Angeles Veterans Affairs Medical Center (Los Angeles, Calif) were prospectively collected from July 1995 to July 1998. Data for patients undergoing elective OAAA repair at these 2 centers during the same period were reviewed retrospectively. Most patients undergoing EAAA repair were outside referrals, whereas most patients undergoing OAAA repair were not. The reasons for outside referral varied. In most instances, referral was the result of patient preference for EAAA repair. In other cases, patients were referred by an outside physician for perceived increased risk for OAAA repair due to prior laparotomy, advanced age, multiple prior myocardial infarctions, poor pulmonary function, or low cardiac ejection fraction. Patients having an emergency operation, those with a suspected ruptured AAA, and those with pararenal, suprarenal, and thoracoabdominal aneurysms were excluded. Cardiac risk factors for each patient, including the Eagle criteria, were recorded. In 6 patients undergoing EAAA repair and in 1 patient undergoing OAAA repair, the presence of a Q wave on ECG could not be determined due to the presence of a pacemaker. Perioperative complications were defined as those occurring within 30 days of surgery or during the index hospital stay. Adverse postoperative cardiac events were defined as Q-wave and non–Q-wave myocardial infarction, CHF, ventricular tachycardia, unstable angina, cardiac arrest, and cardiac death. Myocardial infarction was defined as an elevation of the serum creatinine kinase MB isoenzyme to more than 5% and/or new Q wave on ECG or persistent changes in the ST-sT wave with or without chest pain for longer than 30 minutes. Congestive heart failure was defined as (1) symptoms or signs of pulmonary congestion (shortness of breath or rales); (2) symptoms or signs of new left or right ventricular failure (cardiomegaly, S3 heart sound, jugular venous distention, or peripheral edema); and (3) abnormal chest radiography findings (vascular redistribution and interstitial or alveolar edema). Ventricular tachycardia was defined as consecutive premature ventricular contractions lasting longer than 30 seconds, more than 30 beats, and resulting in hypotension to less than 90 mm Hg. Unstable angina was defined as typical precordial chest pain consistent with ischemia, lasting 30 minutes or longer, unresponsive to nitroglycerin and rest, or a crescendo pattern of angina occurring at a lower threshold or higher frequency. Cardiac arrest and cardiac death were defined as arrest or death from a dysrhythmia or CHF caused by a cardiac complication.

Categorical variables were examined for associations by means of χ2 or Fisher exact tests where appropriate. Continuous variables were compared with the use of the Wilcoxon rank sum test. P<.05 was considered statistically significant. No adjustment was made for multiple comparisons. Factors found to have a significant association on univariate analysis were entered in a multivariate logistic regression analysis. All statistical comparisons were performed with the SAS statistical software package (SAS Institute, Cary, NC).

There were 146 patients who underwent AAA repair (83 EAAA and 63 OAAA). Ninety-two percent were male, with a mean age of 70.7 years (range, 49-88 years). The mean (SD) number of Eagle criteria per patient was 1.2 (1.1). The most frequent Eagle criterion was age older than 70 years (53%), followed by Q wave on ECG (27%), angina (17%), diabetes (13%), history of CHF (11%), and ventricular ectopy requiring therapy (6%). A comparison of clinical risk factors for patients undergoing EAAA and OAAA repair is listed in Table 1. Patients undergoing EAAA repair were significantly older than those undergoing OAAA repair (73 vs 68 years, P=.003), and were more likely to be older than 70 years. There was otherwise no difference in the Eagle risk factors.

Table Graphic Jump LocationTable 1. Comparison of Patients Undergoing EAAA vs OAAA Repair*

Within the OAAA group, 33 (52%) had aortic tube grafts and 30 (48%) had aortoiliac bypasses for combined aortic and iliac aneurysms. All procedures were performed via a transabdominal approach using general anesthesia. The average length of hospital stay was 15.0 days. Within the EAAA group, 60 (72%) had aortic aneurysms alone and 23 (28%) had aortic and iliac aneurysms (P=.01 vs OAAA). All EAAA repairs were performed with a bifurcated modular endovascular prosthesis using general anesthesia in 79 patients (95%), local in 3 patients (4%), and epidural in 1 patient (1%). The average length of hospital stay was 5.7 days (P<.001 vs OAAA).

Eight (5.5%) of the 146 patients suffered adverse cardiac events, including 4 patients with myocardial infarctions (3 Q wave and 1 non–Q wave), 3 patients with CHF alone, and 1 with ventricular tachycardia and CHF. Of the 83 patients undergoing EAAA repair, 5 (6%) had cardiac events, whereas 3 (4%) of the patients undergoing OAAA repair suffered a cardiac event (P>.99).

Within the EAAA group, patients who suffered an adverse cardiac event were significantly older (82 vs 72 years, P=.007), and had a higher mean number of Eagle criteria per patient (3.2 vs 1.1, P<.001) than those without adverse cardiac events. On univariate analysis, Q wave on ECG (P=.006) and history of CHF (P=.005) were the only individual Eagle criteria that were predictive of adverse cardiac events (Table 2). The adverse cardiac event rate was 24% for patients with 2 or more Eagle criteria vs 0% for patients with 1 or no criteria (P=.001).

Table Graphic Jump LocationTable 2. Univariate Analysis of Risk Factors for Adverse Cardiac Events in Patients Undergoing EAAA Repair*

Within the OAAA group, patients with adverse cardiac events also had a significantly higher mean number of Eagle criteria per patient (3.3 vs 1.2, P=.01) but they were not significantly older (67 vs 72 years, P=.81) than those without adverse cardiac events. On univariate analysis, Q wave on ECG (P=.03), ventricular ectopy (P=.02), and history of CHF (P=.001) were the individual Eagle criteria that were predictive of adverse cardiac events. The adverse cardiac event rate was 15% for patients with 2 or more Eagle criteria vs 0% for patients with 1 or no criteria (P=.03).

When we analyzed the patients undergoing EAAA or OAAA repair together, Q wave on ECG (P<.001), ventricular ectopy (P=.007), and a history of CHF (P<.001) were the Eagle criteria predictive of adverse cardiac events on univariate analysis, whereas diabetes (P=.07), angina, and age older than 70 years were not. No association was observed between EAAA repair and the occurrence of adverse cardiac events (odds ratio, 1.28; 95% confidence interval, 0.29-5.59). Because patients having EAAA repair were significantly older than those having OAAA repair, we performed an age-stratified analysis (age <70 vs ≥70 years) of the association between procedure type and adverse cardiac events using a Cochran-Mantel-Haenszel χ2 test. This analysis found no association between procedure type and major cardiac events (odds ratio, 1.22; 95% confidence interval, 0.22-6.85). The cardiac event rate according to the number of Eagle criteria present is presented in Table 3. The cardiac event rate was 19.5% for patients with 2 or more Eagle criteria vs 0% for those with 1 or no criteria (P<.001). On multivariate logistic regression analysis with stepwise variable selection, only history of CHF (P=.002) and Q wave on ECG (P=.04) were predictive of adverse events.

Table Graphic Jump LocationTable 3. Cardiac Event Rate by Number of Eagle Criteria

There were a total of 6 (4.1%) postoperative deaths, of which 3 were EAAA and 3 were OAAA patients. Only 1 (0.7%) (in a patient undergoing EAAA repair) was of cardiac origin. The causes of the remaining noncardiac deaths were diffuse embolization with bowel ischemia (EAAA), gangrenous cholecystitis with sepsis (EAAA), and 1 patient each with a pulmonary complication, multisystem organ failure, and variceal bleeding from portal hypertension (all OAAA).

Our study demonstrated no difference in adverse cardiac event rate or postoperative mortality between EAAA and OAAA repair. Cardiac event rate was 6% for EAAA vs 5% for OAAA, whereas postoperative mortality was 4% for EAAA vs 5% for OAAA. Patients undergoing EAAA repair were significantly older. We therefore performed an age-stratified analysis that found no association between type of aortic abdominal aneurysm repair and adverse cardiac events. Additionally, there was no difference in the mean number of Eagle criteria per patient in the 2 groups, suggesting an equivalent cardiac risk. However, several limitations of the study should be addressed. First, data on OAAA repair were gathered retrospectively, whereas data on EAAA repair were prospective. Thus, some cardiac events in the former group may have been underdiagnosed. Second, many patients undergoing EAAA repair were referred from outside institutions, whereas patients undergoing OAAA repair were not. Many patients undergoing EAAA repair were referred because they were deemed to be high-risk candidates for OAAA repair, either because of advanced age or other comorbidities. These comorbidities, such as multiple prior myocardial infarctions, low cardiac ejection fraction, and pulmonary disease, may not be reflected accurately by the Eagle criteria.

Most other studies on EAAA repair have focused on the technical complications related to the procedure, though some data on cardiac morbidity and mortality are available. May et al7 reported 8 cardiac complications (7%) in 108 patients who underwent attempted EAAA repair, with a 2.7% cardiac mortality. Moore et al2 noted 1 myocardial infarction (2%) in 46 patients undergoing EAAA repair with no cardiac deaths.

Baxendale et al11 have demonstrated that EAAA repair causes less intraoperative hemodynamic and metabolic stress on the patient compared with OAAA repair. They noted a significant change in cardiac output, mean arterial pressure, and systemic vascular resistance related to aortic cross-clamping and lower limb reperfusion. With EAAA repair, there was only a transient rise in systemic vascular resistance with femoral artery clamping. Thus, one would anticipate a lower cardiac morbidity and mortality rate for EAAA repair. This expected reduction in cardiac morbidity was not noted in our study. This may be the result of a combination of factors. The EAAA repairs in our study were performed under general anesthesia, which itself is a major cardiac stress. Second, as mentioned earlier, patients undergoing EAAA repair may have had a greater cardiac risk than what was reflected by the Eagle criteria. We have since begun to selectively use local anesthesia for our high-risk patients undergoing EAAA repair. Whether this change in anesthetic approach will affect the cardiac event rate remains to be seen.

The Eagle criteria have previously been demonstrated to be useful predictors of adverse cardiac events for patients undergoing major vascular surgery.810 Eagle et al10 reported a 3% adverse cardiac event rate in patients with no clinical criteria, a 15% event rate for those with 1 or 2 criteria, and a 50% event rate for those with 3 or more criteria. Our 2 previous studies of patients undergoing elective major vascular surgery confirmed the value of the Eagle criteria.8,9 We reported no cardiac morbidity or mortality for patients without a single criterion and a 7% cardiac event rate with 1 or more criteria (P<.05). To our knowledge, no one has investigated the utility of the Eagle criteria for patients undergoing EAAA repair. The present study demonstrated that Q wave on preoperative ECG and a history of CHF were predictors of postoperative cardiac morbidity for both OAAA and EAAA repair. Additionally, in patients with 2 or more Eagle criteria, the adverse cardiac event rate increased from 0% to 19.5%. The high cardiac morbidity associated with 2 or more criteria raises the question of the role of cardiac assessment in these patients. The present study did not attempt to answer the question of whether cardiac assessment is justified. Future studies are needed to address this important issue. Currently we are assessing whether the performance of EAAA with local or spinal anesthesia will reduce the perioperative cardiac morbidity in these high-risk patients.

In summary, our study demonstrated no difference in adverse cardiac event rates or postoperative mortality rates between patients undergoing OAAA and EAAA repair. For patients with 2 or more Eagle criteria, the cardiac event rate rose to 19.5% compared with no cardiac morbidity for patients with only 1 criterion or no criteria. On multivariate analysis, Q wave on preoperative ECG and a history of CHF were predictive of cardiac events for both EAAA and OAAA repair. Future studies on cardiac risk assessment prior to AAA repair should focus on this subgroup of patients.

This study was supported in part by a grant from the Harbor-UCLA Research and Education Institute, Torrance, Calif (Dr de Virgilio).

Presented at the 70th Annual Session of the Pacific Coast Surgical Association, San Jose del Cabo, Baja California Sur, February 14, 1999.

We thank Roger J. Lewis, MD, PhD, for statistical analysis.

Corresponding author: Christian de Virgilio, MD, Harbor-UCLA Medical Center, Division of Vascular Surgery, 1000 W Carson St, Box 25, Torrance, CA 90509.

Parodi  JPalmaz  JBarone  H Transfemoral intraluminal graft implantation for abdominal aortic aneurysms. Ann Vasc Surg. 1991;5491- 499
Link to Article
Moore  WRutherford  Rfor the EVT Investigators, Transfemoral endovascular repair of abdominal aortic aneurysm: results of the North American EVT phase I trial. J Vasc Surg. 1996;23543- 553
Link to Article
Parodi  J Endovascular repair of abdominal aortic aneurysms and other arterial lesions. J Vasc Surg. 1995;21549- 557
Link to Article
Mialhe  CAmicabile  CBecquemin  J Endovascular treatment of infrarenal abdominal aortic aneurysms by the Stentor system: preliminary results in 79 cases. J Vasc Surg. 1997;26199- 209
Link to Article
Chuter  TRisberg  BHopkinson  B  et al.  Clinical experience with a bifurcated endovascular graft for abdominal aneurysm repair. J Vasc Surg. 1996;24655- 666
Link to Article
White  RDonayre  CWalot  I  et al.  Modular bifurcation endoprosthesis for treatment of abdominal aortic aneurysms. Ann Surg. 1997;226381- 391
Link to Article
May  JWhite  GYu  W  et al.  Concurrent comparison of endoluminal versus open repair in the treatment of abdominal aortic aneurysms: analysis of 303 patients by the life table method. J Vasc Surg. 1998;27213- 221
Link to Article
de Virgilio  CKirby  LLewis  RJ  et al.  Limited utility of dipyridamole-thallium for predicting adverse cardiac events after vascular surgery. Vasc Surg. 1998;32275- 279
Link to Article
de Virgilio  CPak  SArnell  T  et al.  Cardiac assessment prior to vascular surgery: is dipyridamole-sestamibi necessary? Ann Vasc Surg. 1996;10325- 329
Link to Article
Eagle  KColey  CNewell  J  et al.  Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery. Ann Intern Med. 1989;110584- 587
Link to Article
Baxendale  BBaker  DHutchinson  A  et al.  Haemodynamic and metabolic response to endovascular repair of infra-renal aortic aneurysms. Br J Anaesth. 1996;77581- 585
Link to Article

Fred A. Weaver, MD, Los Angeles, Calif: This latest study analyzes the cardiac morbidity associated with open aneurysm repair vs endovascular stent graft replacement. Sixty-three open procedures were compared with 83 endovascular repairs. Development of myocardial infarction, congestive heart failure, ventricular tachycardia, unstable angina, cardiac arrest, or death served as primary end points. Eagle criteria were catalogued for all patients. Contrary to what has been touted as an advantage of the less-invasive endovascular repair, no significant difference in cardiac morbidity or mortality could be demonstrated between an open or an endovascular approach. The reasons for this are uncertain, and I would like the authors to comment or at least speculate on why they might think this would be so. It should also be noted that although the endovascular group was somewhat older, the Eagle criteria and thus the cardiac risk factors were equivalent. Another interesting point is that the cardiac-related morbidity was remarkably low in this particular series, with only 1 of the 6 deaths being directly related to cardiac morbidity. The rest of the deaths were due to noncardiac causes such as sepsis and respiratory and multiorgan system failure. The authors analyzed the patients' cardiac outcome by preoperative Eagle criteria using a univariate analysis and multivariate logistic regression analysis. Only Q wave on ECG or a history of congestive heart failure were found to be uniquely predictive of cardiac morbidity in the 146 aneurysm procedures. It was also found that patients with less than or equal to 1 Eagle criteria had no cardiac morbidity, whereas all cardiac morbidity was clustered in those individuals with 2 or more Eagle criteria.

This is a very interesting paper and, although somewhat compromised by the retrospective nature of the open analysis vs the prospective nature of the endovascular analysis, it does challenge the perception of physicians, surgeons, and patients that endovascular aneurysm repair is inherently safer than an open approach.

There are a few questions that I would like the authors to address. First, what kind of anesthetic was used for these procedures? Was the anesthesia used for the open procedure equivalent to the endovascular procedures? What kind of intraoperative hemodynamic monitoring was used? Was the monitoring for both procedures more or less the same?

Second, how were the open procedures performed, retroperitoneal or transperitoneal? How many of the aortic aneurysms had iliac aneurysms as well, which, at least in my hands, makes for a more difficult open operation? Concerning the endovascular repair, were these all bifurcated prostheses or were tube stent graft prostheses used as well? You identified 2 specific Eagle criteria that were unique, highly predictive of cardiac events. Were all of the cardiac events that occurred clustered in patients with 1 or both of these criteria, making the rest of the Eagle criteria really irrelevant?

Finally, you have studied and written a great deal on the cardiac evaluation of the patient undergoing vascular surgery. At present what are your recommendations? When do you obtain a noninvasive cardiac assessment such as persantine thallium or dobutamine echo? When should the patient have a cardiac cath?

Samuel E. Wilson, MD, Orange, Calif: Why, after a less traumatic procedure, do the cardiac complications and morbidity occur with roughly the same incidence as after the open procedure?

Dr Stabile: Our expectation with this study was that we would find that endovascular aneurysm repair would have a lower cardiac event rate, a lower cardiac death rate, and a lower overall death rate than open aneurysm repair. This clearly was not realized by the results of this study, but this is a preliminary study and we clearly have additional work to do and perhaps a more sophisticated analysis of risk factors will be required.

The 2 treatment groups were very similar with respect to the Eagle criteria and, as Dr de Virgilio and the vascular group have shown in several prior studies, the Eagle criteria were again very highly predictive of cardiac events. The only significant difference amongst the Eagle criteria was that the endovascular treatment group was significantly older than the open treatment group. This was particularly true for the endovascular group of patients who had cardiac events. That group was fully 9 years older, with a mean age of 82 years, as compared with the remainder of the group, who suffered no cardiac events. The Eagle criteria were predictive in a very reliable way in that 2 or more criteria had a cardiac event rate of 20% whereas 1 or no criteria had 0 cardiac events. This corroborates a growing body of evidence suggesting this simple clinical assessment is highly valuable to the clinician in planning elective vascular operations.

Dr Weaver pointed out the obvious limitation of the study, and that is comparing a prospectively evaluated endovascular group with a retrospectively evaluated open aneurysmectomy group. This is important because the majority of the endovascular patients were referred specifically because the referring physician had assessed the patient to be at high risk. The Eagle criteria unfortunately do not encompass all of the risk factors that are pertinent, such as low ejection fraction, multiple prior myocardial infarctions, recent severe cardiac symptoms, and noncardiac problems such as severe chronic obstructive pulmonary disease. Thus, we do not feel that the Eagle criteria give a full risk assessment. Potentially lethal adverse outcomes can occur, and we need to find assessment tools to evaluate those.

These considerations may have obscured both higher risk in the endovascular group, as well as possibly more severe and unappreciated adverse outcomes in the open-treated group because of the retrospective nature of that evaluation.

Dr Weaver asked that we specifically speculate on the lack of outcome differences. We need a better preoperative risk stratification system that takes into account cardiac issues not specifically encompassed by the Eagle criteria and also noncardiac potential morbidity.

The anesthesia was general anesthesia for all patients. There was no difference in the anesthetic technique for the open vs the endovascular groups, and in general the same monitoring was used based on the same criteria. All open operations were transperitoneal. I do not have specific information, Dr Weaver, relating to the number of more complex aneurysms involving the iliac vessels.

Early in the experience, straight tube grafts were exclusively used in the endovascular-treated group, but the vast majority of the patients now are being treated with a modular bifurcated device. We did find that a history of congestive heart failure and Q waves were by far the most predictive, and were the only independent predictors amongst the Eagle criteria. The others may well be irrelevant as suggested.

Dr Wilson asked the causes of 5 of 6 deaths, as only 1 was a cardiac death. They were due to a variety of causes. The minority were technically related and occurred early in the experience with the endovascular devices. One patient had diffuse embolization to the bowel that resulted in sepsis and ultimately multiple organ failure. Another patient had acalculous cholecystitis that went on to gangrene, sepsis, and multiple organ failure. The other deaths were essentially anesthesia related. So there was a multiplicity of causes of death other than the 1 cardiac death. Again, I think this specifically points out the fact that we need a better and more comprehensive system for patient risk evaluation and only then will we be able to better select patients for endovascular vs open therapy.

Figures

Tables

Table Graphic Jump LocationTable 1. Comparison of Patients Undergoing EAAA vs OAAA Repair*
Table Graphic Jump LocationTable 2. Univariate Analysis of Risk Factors for Adverse Cardiac Events in Patients Undergoing EAAA Repair*
Table Graphic Jump LocationTable 3. Cardiac Event Rate by Number of Eagle Criteria

References

Parodi  JPalmaz  JBarone  H Transfemoral intraluminal graft implantation for abdominal aortic aneurysms. Ann Vasc Surg. 1991;5491- 499
Link to Article
Moore  WRutherford  Rfor the EVT Investigators, Transfemoral endovascular repair of abdominal aortic aneurysm: results of the North American EVT phase I trial. J Vasc Surg. 1996;23543- 553
Link to Article
Parodi  J Endovascular repair of abdominal aortic aneurysms and other arterial lesions. J Vasc Surg. 1995;21549- 557
Link to Article
Mialhe  CAmicabile  CBecquemin  J Endovascular treatment of infrarenal abdominal aortic aneurysms by the Stentor system: preliminary results in 79 cases. J Vasc Surg. 1997;26199- 209
Link to Article
Chuter  TRisberg  BHopkinson  B  et al.  Clinical experience with a bifurcated endovascular graft for abdominal aneurysm repair. J Vasc Surg. 1996;24655- 666
Link to Article
White  RDonayre  CWalot  I  et al.  Modular bifurcation endoprosthesis for treatment of abdominal aortic aneurysms. Ann Surg. 1997;226381- 391
Link to Article
May  JWhite  GYu  W  et al.  Concurrent comparison of endoluminal versus open repair in the treatment of abdominal aortic aneurysms: analysis of 303 patients by the life table method. J Vasc Surg. 1998;27213- 221
Link to Article
de Virgilio  CKirby  LLewis  RJ  et al.  Limited utility of dipyridamole-thallium for predicting adverse cardiac events after vascular surgery. Vasc Surg. 1998;32275- 279
Link to Article
de Virgilio  CPak  SArnell  T  et al.  Cardiac assessment prior to vascular surgery: is dipyridamole-sestamibi necessary? Ann Vasc Surg. 1996;10325- 329
Link to Article
Eagle  KColey  CNewell  J  et al.  Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery. Ann Intern Med. 1989;110584- 587
Link to Article
Baxendale  BBaker  DHutchinson  A  et al.  Haemodynamic and metabolic response to endovascular repair of infra-renal aortic aneurysms. Br J Anaesth. 1996;77581- 585
Link to Article

Correspondence

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