| | Endovascular aneurysm repair at 5 years: does aneurysm diameter predict outcome?Presented at the Annual Meeting of the Southern Association for Vascular Surgery, Phoenix, Ariz, Jan 21, 2006. Received 21 January 2006; accepted 27 June 2006. ObjectiveThe appropriate size threshold for endovascular repair of small abdominal aortic aneurysms (AAA) is unclear. We studied the outcome of endovascular aneurysm repair (EVAR) as a function of preoperative aneurysm diameter to determine the relationship between aneurysm size and long-term outcome of endovascular repair. MethodsWe reviewed the results of 923 patients treated in a prospective, multicenter clinical trial of EVAR. Small aneurysms were defined according to two size thresholds of 5.5 cm and 5.0 cm. Two-way analysis was used to compare patients with small aneurysms (<5.5 cm, n = 441) to patients with large aneurysms (≥5.5 cm, n = 482). An ordered three-way analysis was used to compare patients with small AAA (<5.0 cm, n = 145), medium AAA (5.0 to 5.9 cm, n = 461), and large AAA (≥6.0 cm, n = 317). The primary outcome measures of rupture, AAA-related death, surgical conversion, secondary intervention, and survival were compared using Kaplan-Meier estimates at 5 years. ResultsMedian aneurysm size was 5.5 cm. The two-way comparison showed that 5 years after EVAR, patients with small aneurysms (<5.5 cm) had a lower AAA-related death rate (1% vs 6%, P = .006), a higher survival rate (69% vs 57%, P = .0002), and a lower secondary intervention rate (25% vs 32%, P = .03) than patients with large aneurysms (≥5.5 cm). Three-way analysis revealed that patients with small AAAs (<5.0 cm) were younger (P < .0001) and were more likely to have a family history of aneurysm (P < .05), prior coronary intervention (P = .003), and peripheral occlusive disease (P = .008) than patients with larger AAAs. Patients with smaller AAAs also had more favorable aortic neck anatomy (P < .004). Patients with large AAAs were older (P < .0001), had higher operative risk (P = .01), and were more likely to have chronic obstructive pulmonary disease (P = .005), obesity (P = .03), and congestive heart failure (P = .004). At 5 years, patients with small AAAs had better outcomes, with 100% freedom from rupture vs 97% for medium AAAs and 93% for large AAAs (P = .02), 99% freedom from AAA-related death vs 97% for medium AAAs and 92% for large AAAs (P = .02) and 98% freedom from conversion vs 92% for medium AAAs and 89% for large AAAs (P = .01). Survival was significantly improved in small (69%) and medium AAAs (68%) compared to large AAAs (51%, P < .0001). Multivariate Cox proportional hazards modeling revealed that aneurysm size was a significant independent predictor of rupture (P = .04; hazard ratio [HR], 2.195), AAA-related death (P = .03; HR, 2.007), surgical conversion (P = .007; HR, 1.827), and survival (P = .001; HR, 1.351). There were no significant differences in secondary intervention, endoleak, or migration rates between small, medium, and large AAAs. ConclusionsPreoperative aneurysm size is an important determinant of long-term outcome following endovascular repair. Patients with small AAAs (<5.0 cm) are more favorable candidates for EVAR and have the best long-term outcomes, with 99% freedom from AAA death at 5 years. Patients with large AAAs (≥6.0 cm) have shorter life expectancy and have a higher risk of rupture, surgical conversion, and aneurysm-related death following EVAR compared to patients with smaller aneurysms. Nonetheless, 92% of patients with large AAAs are protected from AAA-related death at 5 years. Patients with AAAs of intermediate size (5 to 6 cm) represent most of the patients treated with EVAR and have a 97% freedom from AAA-related death at 5 years. Aneurysm size is the primary determinant of the risk of aneurysm rupture and is an important predictor of long-term survival in patients with abdominal aortic aneurysms (AAAs).1 The differentiation between small and large aortic aneurysms is usually a threshold diameter of 5.5 cm. Aneurysms <5.5 cm in diameter are considered to be small, whereas those >5.5 cm are considered to be large. A number of prospective randomized clinical trials of both open and endovascular aneurysm treatment have used this threshold definition, and different treatment strategies have been proposed for small and large aneurysms.2, 3, 4, 5, 6, 7, 8 Yet, all clinical trials of endovascular aneurysm repair (EVAR) include patients with both small and large aneurysms, with most aneurysms sized 5 to 6 cm. The mean diameter of aneurysms treated in prospective clinical trials leading to US Food and Drug Administration (FDA) endograft device approval was 5.6 cm.9 Although it is recognized that patients with small aneurysms have a better early and late outcome after EVAR than patients with large aneurysms,10, 11, 12, 13 the precise relationship between aneurysm size and outcome after EVAR is unclear. The purpose of this investigation was to better define the relationship between preoperative aortic aneurysm diameter and long-term outcome after EVAR. We differentiated between small and large aneurysms by using both the usual 5.5-cm threshold diameter and also by segmenting the population of patients treated into small (<5.0 cm), medium (5.0 to 5.9 cm), and large (≥6.0 cm) aortic aneurysms. Methods  We reviewed the early and long-term results of 923 patients treated in the prospective, multicenter investigational device exemption (IDE) clinical trial of EVAR using the AneuRx stent graft (Medtronic, Minneapolis, Minn). Results of the entire 1193-patient cohort have been previously reported.14, 15 These reports include all patients treated during the course of the clinical trial, including off-protocol/emergent-use patients and those treated with early device designs (stiff modular bifurcation, pre-RPM fabric) that are not in clinical use. In this study, we included only patients treated with the commercially available device (flexible bifurcation module, RPM fabric). Patients were treated from 1998 to 1999 and followed up with periodic clinical examination and computed tomographic (CT) scan or other imaging for a minimum of 5 years as required by the FDA as a condition of device approval. The 19 clinical sites that participated in the clinical trial were externally monitored, and data were entered into the New England Research Institute (NERI) data base.16 Baseline aneurysm diameter was defined as the maximum transverse aneurysm diameter as measured on the preprocedure CT scan. Median preoperative aneurysm size was 5.5 cm, and a histogram of aneurysm sizes is shown in Fig 1. Because there was no clear separation between small and large aneurysms, we considered the relationship between aneurysm size and outcome in two ways: 1.We used the customary threshold diameter of 5.5 cm to compare patients with small aneurysms (≤5.4 cm) with patients with large aneurysms (≥5.5 cm) by using a two-way comparison. 2.We compared patients with small AAA (<5.0 cm), medium AAA (5.0 to 5.9 cm), and large AAA (≥6.0 cm) by using a three-way comparison. Baseline characteristics were evaluated for the each of the three groups (small, medium, large) and included age, gender, aneurysm neck diameter, neck length, and other risk factors such as American Society of Anesthesiologists (ASA) grade, family history of aneurysm disease, myocardial infarction, angina, obesity, hypertension, chronic renal failure, previous abdominal surgery, chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), prior coronary intervention, prior stroke, peripheral occlusive disease, diabetes, smoking, and cancer. Five long-term primary outcome measures were evaluated using Kaplan-Meier analysis and included aneurysm rupture (perioperative and late), aneurysm-related death (perioperative and late), surgical conversion (elective and emergent), secondary intervention (excluding surgical conversion), and survival (all-cause mortality). Secondary outcome measures (endoleak, stent-graft migration, and AAA enlargement) were also evaluated and compared across the three groups. Statistical analysis Statistical analyses were performed using SAS 9.1 (SAS Inc, Cary, NC). Baseline descriptive statistics for each group are expressed as means and standard deviations for continuous outcomes and percentages for binary or ordered factors. Differences among the three groups for baseline factors were determined using the Jonckheere-Terpstra test. The null hypothesis that all three groups were equal was tested against the one-sided ordered alternative hypothesis (small ≥ medium ≥ large; or small ≤ medium ≤ large, with at least one strict inequality). The five outcomes of freedom from rupture, AAA-related death, conversion, secondary intervention, and survival were expressed as Kaplan-Meier estimates with standard errors. Difference among the three groups with respect to these five outcomes was determined using the ordered log-rank test. The null hypothesis that the results for all three groups are equal was tested against the ordered alternative hypothesis. To consider the effect of influential baseline covariates that were out of balance between the three groups, multivariate Cox proportional hazard models were created for outcomes found to be statistically significantly different across the three groups. Differences between the two groups (small AAAs vs large AAAs) were assessed for significance using χ2 for binary factors, Wilcoxon two-sample rank test for ASA grade, or the t test for continuous factors. The five long-term outcomes were stratified into small AAAs vs large AAAs and were expressed as Kaplan-Meier estimates with standard errors and compared using the log-rank test. Statistical significance was defined as P < .05. Results Aneurysm size distribution The distribution of preoperative aneurysm diameters among the 923 patients included in this study is shown in Fig 1. Median aneurysm size was 5.5 cm (mean, 5.7 ± 1.5 cm). Among the 923 patients, 441 (48%) had small aneurysms and 482 (52%) had large aneurysms in the two-group analysis. For the three-way analysis, 145 patients (16%) had small aneurysms, 461 (50%) had medium aneurysms, and 317 (34%) had large aneurysms. Patient characteristics Baseline patient characteristics for the three-group comparison of aneurysm sizes are summarized in Table I. Compared with patients with larger AAAs, patients with small AAAs were younger (P < .0001), had more peripheral occlusive disease (P = .008), and were more likely to have a family history of aneurysm (P = .05). They were also a better operative risk (lower ASA grade) (P = .01) and were more likely to have had coronary intervention before aneurysm repair. Patients with larger AAAs were more likely to have COPD (P = .005), CHF (P = .004), and obesity (P = .03). Baseline aortic neck morphology Patients with small aneurysms had more favorable preoperative aortic neck anatomy for endovascular repair. They had smaller aortic neck diameters (P < .0001) and greater aortic neck lengths compared with patients with larger aneurysms (Table I). Small vs large aneurysms (two-way comparison) Primary end-point analyses of small (<5.5 cm) compared with large (≥5.5 cm) aneurysms are summarized in Table II. Five years after EVAR, patients with small aneurysms were less likely to have died of an aneurysm-related event (P = .006) or to have required a secondary intervention (P = .03), and they had a higher survival rate (P = .0002) than patients with large aneurysms. There was no significant difference in risk of rupture or surgical conversion between small and large aneurysms. Small AAA vs medium AAA vs large AAA (three-way comparison) Three-way primary end-point comparisons using Kaplan-Meier analyses are shown in Fig 2, Fig 3, Fig 4, Fig 5, Fig 6. Rupture Freedom from rupture at 5 years was 100% for small AAA, 97% for medium, and 93% for large. These differences were significant by ordered log-rank test (P = .02; Fig 2). Aneurysm-related death Freedom from AAA-related death at 5 years was 99% for small AAA, 97% for medium, and 92% for large. These differences were significant by ordered log-rank test (P = .02; Fig 3). Surgical conversion Freedom from surgical conversion at 5 years was 98% for small AAA, 92% for medium, and 89% for large. These differences were significant by ordered log-rank test (P = .01; Fig 4.) Secondary interventions Freedom from secondary intervention at 5 years was 76% for small AAA, 73% for medium, and 67% for large. These differences were not statistically significant (ordered log-rank test, P = .09; Fig 5). Survival Survival at 5 years was 89% for small AAA, 68% for medium, and 51% for large. These differences were significant by ordered log-rank test (P < .0001; Fig 6). Multivariate analysis Cox proportional hazards models revealed that even after adjusting for baseline covariates that were out of balance between the three groups, AAA size remained a significant predictor of rupture (P = .04; hazard ratio [HR], 2.195), AAA-related death (P = .03; HR, 2.007), surgical conversion (P = .007; HR, 1.827), and survival (P = .001; HR, 1.351). The results of applying the Cox proportional hazard model for survival are summarized in Table III. This multivariate regression model revealed that in addition to aneurysm size, significant predictors of survival included age (P < .0001), surgical risk by ASA grade (P = .0003), COPD (P < .0001), and peripheral vascular disease (P = .002). Secondary outcome measures Secondary outcome measures as recorded by the clinical centers are listed in Table IV as rates at each annual follow-up time point. No significant differences were found in endoleak rate or migration rate between small, medium, and large aneurysms over a 4-year period, nor was a significant difference found in aneurysm enlargement rate between small, medium, and large aneurysms through 3 years. At 4 years, however, 19% of large aneurysms were enlarged >5 mm over baseline, a considerably increased rate compared with the 14% in medium-sized AAA group and 7% in the small-sized AAA group (P = .05). Discussion A diameter of 5.5 cm is commonly considered to represent the dividing line between small and large aneurysms; however, aneurysm size distribution is approximated by a unimodal normal bell-shaped curve, as shown in Fig 1, rather than by a bimodal distribution curve of small and large aneurysms. Thus, if a diameter of 5.5 cm is used to compare small with large aneurysms, a large number of patients in both groups will have “average-sized” aneurysms, close to the mean. Indeed, the mean aneurysm size treated in this study was 5.7 cm (median, 5.5 cm), and 50% of patients had aneurysms in the diameter range of 5.0 to 5.9 cm. The mean aneurysm diameter reported in the Lifeline Registry of 2664 patients treated in 4 IDE clinical trials leading to FDA device approval was 5.6 ± 1.0 cm.9 The largest number of patients treated in our series were in the size range of 5.0 to 5.4 cm. A similar size frequency distribution was noted in The Cleveland Clinic experience,16 with the largest number of patients having a diameter of 5.0 to 5.5 cm. In the prospective small aneurysm trials,3, 17 the cohort with this aneurysm size (5.0 to 5.4 cm) had the highest risk of aneurysm rupture and death among patients with small aneurysms randomized to surveillance.3, 18 This raises the question of whether aneurysms of 5.0 to 5.4 cm are truly representative of “small aneurysms,” particularly in women, or whether they more closely resemble “medium size” aneurysms. We addressed this issue by defining small aneurysms to be those <5.0 cm in diameter and performing an ordered three-way comparison of small, medium, and large aneurysms. We also performed a two-way analysis using the traditional 5.5-cm threshold to differentiate small from large aneurysms. Using the traditional 5.5-cm threshold of aneurysm size, we found that 48% of our patients had small aneurysms (<5.5 cm). This is similar to the EUROSTAR Registry, where 45% of patients had small aneurysms,10 and lower than The Cleveland Clinic, where 59% of patients had small aneurysms.12 Our two-way analysis of small vs large aneurysms showed that patients with large aneurysms were older (75 years vs 72 years, P < .0001), had a higher AAA-related death rate at 5 years (6.4% vs 1.4%, P = .006), and had reduced survival at 5 years (57% vs 69%, P = .0002) compared with patients with small aneurysms. Patients with large aneurysms were more likely to need a secondary procedure during the 5-year follow-up period (32% vs 25%, P = .03). Although there was a trend for increased rupture (5.3% vs 1.8%, P = .08) and increased surgical conversion (10.2% vs 5.7%, P = .06) in patients with large aneurysms at 5 years, these differences were not statistically significant. Similar findings were reported from the EUROSTAR and The Cleveland Clinic experiences.10, 12, 13 In our three-way analysis, we used a 5.0-cm threshold for small aneurysms and defined small AAA as <5.0 cm, medium AAA as 5.0 to 5.9 cm and large AAA as ≥6.0 cm. The small AAA group comprised 16%, the medium AAA group comprised 50%, and the large AAA group comprised 34% of the patients treated. Although our two-way analysis had found that age and COPD were the only significant differences between patients with small and large aneurysms, the three-way analysis suggested that patients with small AAA might represent a different patient population from patients with large AAA, with medium AAA patients having intermediate baseline characteristics. Patients with smaller aneurysms were younger, had more peripheral occlusive disease, and were more likely to have a family history of aneurysm. They also were more likely to have undergone coronary revascularization and were in a lower ASA risk category, which may have contributed to improved survival. Patients with larger aneurysms, on the other hand, were older, had higher preoperative risk classification, and were more likely to have COPD, obesity, and CHF. Comparison of the Kaplan-Meier curves shows that patients with large AAAs have a significantly shorter life expectancy than those with smaller AAAs. This is consistent with the EUROSTAR finding that EVAR patients with the largest aneurysms had the shortest survival10 and the findings by Ouriel et al12 that patients with large aneurysms have diminished survival at 24 months. Interestingly, our medium AAA group was very similar to the small AAA group with respect to survival (68% and 69%) but paralleled the large AAA group on the Kaplan-Meier analyses of aneurysm-specific outcome measures such as rupture, aneurysm-related death and surgical conversion (see Figs). Multivariate analysis showed that aneurysm size was a significant independent predictor of survival, but that other factors were also important in predicting survival, including age, surgical risk, COPD, and peripheral occlusive disease. The EUROSTAR analysis similarly showed that increased aneurysm size was a significant predictor of decreased survival along with age, renal dysfunction, and pulmonary disease.13 Aneurysm-specific endpoints showed that patients with small AAA had the best outcomes compared with patients with medium and large AAA. There were no aneurysm ruptures among the small AAA patients, and larger aneurysm size was the only significant independent predictor of the risk of rupture. Although the risk of aneurysm rupture in patients with small aneurysms is known to be low, it is not negligible. In a population-based study, Reed et al19 estimated the annual risk of rupture of 1% for aneurysms sized 4.0 cm to 4.9 cm, with 95% confidence intervals of 0% to 5% per year. Scott et al20 reported an annual rupture rate of 0.7% for aneurysms sized 3.0 to 4.4 cm and an annual rupture rate of 1.7% for aneurysms of 4.5 to 4.9 cm. Similar estimates were reported from the UK Small Aneurysm Trial, where the annual risk of rupture was 0.3% for aneurysms <4 cm and 1. 5% for aneurysms of 4.0 to 4.9 cm.21 Thus, the 5-year risk of rupture in untreated aneurysms <5 cm may exceed 5%. Our finding of complete protection from aneurysm rupture through a 5-year period after endovascular repair of aneurysms <5.0 cm demonstrates the effectiveness of this form of therapy in patients with small aneurysms. More favorable preoperative aortic neck anatomy in patients with small-sized aneurysm may have been an important factor in this long-term success. Ruptures were confined to patients with large-sized (rupture in 7% of patients at 5 years) and medium-sized aneurysms (rupture in 3% of patients at 5 years) and were consistent with the known increased risk of rupture with increasing aneurysm size. Factors that may be important in predisposing to rupture, such as endoleak and migration, were no different in patients with small, medium, or large aneurysms. However, aneurysm enlargement after EVAR was significantly more likely in patients with large aneurysms (19% at 4 years) than in patients with smaller aneurysms. Only one aneurysm-related death occurred among our small AAA patients, and this was a perioperative death in a patient who died of respiratory failure 2 weeks after device implantation. There were no late AAA-related deaths in small AAA patients. Aneurysm-related death rate by Kaplan-Meier analysis at 4 and 5 years in our small AAA (<5.0 cm) group was 0.7% compared with a 3% AAA death rate at 4 years reported for small aneurysms from the EUROSTAR registry, where small aneurysms were defined as 4.0 to 5.4 cm.10 The AAA death rate at 4 years was 3% for medium sized aneurysms (5.0 to 5.9 cm) and 8% for large aneurysms (≥6.0 cm) in our study (P = .02). The 4-year AAA-related death rates for those in the middle size range (5.5 to 6.4 cm) in the EUROSTAR registry was 5% with the highest AAA-related death rate of 12% at 4 years occurring in their largest aneurysm group (≥6.5 cm).10 Thus, the risk of aneurysm-related death was exceedingly low for patients with aneurysms <5.0 cm. Patients with aneurysms <5.0 cm were also much less likely to require surgical conversion during a 5-year follow-up period than were patients with larger aneurysms. Only two patients in our small AAA group underwent surgical conversion. One was at the time of the initial procedure owing to failure to access the aorta through small iliac arteries. The other was an elective surgical conversion at 32 months because of a persisting type II endoleak and aneurysm enlargement. Kaplan-Meier analysis showed that the risk of surgical conversion at 5 years was 1.6% in the small AAA group compared with 8% for medium and 11% for large aneurysms (P = .01). These favorable results may in part be due to more favorable aortic neck morphology in small AAA patients. The rate of surgical conversion for small (4.0 to 5.4 cm) and large (5.5 to 6.4 cm) aneurysms was 7% at 4 years in the EUROSTAR registry, comparable to our 7% conversion rate for both medium AAA and large AAA aneurysms at 4 years. A higher risk of surgical conversion at 4 years was noted in the EUROSTAR registry for patients with the largest aneurysms (14% for aneurysms ≥6.5 cm).10 There were significantly fewer secondary interventional procedures in patients with small aneurysms (<5.5 cm) than large aneurysms (25% vs 31%, P = .03) in our two-way analysis. In the three-way analysis, however, the differences in secondary intervention rate at 5 years among small (24%), medium (27%), and large AAAs (33%, P = .09, ordered log-rank test) did not reach statistical significance. Patients with large aneurysms were more likely to have late (4 year) aneurysm enlargement, consistent with the increased risk of late aneurysm rupture. Thus, defining small aneurysms as <5.0 cm identified a patient population that had the best long-term outcomes of endovascular repair with no aneurysm ruptures and almost no aneurysm-related deaths. Furthermore, it differentiated a population of aneurysm patients with more favorable preoperative characteristics and lower risk than patients with larger aneurysms. Patients with aneurysms of 5.0 to 5.4 cm represented the largest single aneurysm size cohort, and inclusion of these patients in the small aneurysm group could potentially mask real differences in long-term outcome analysis of patients with small aneurysms, particularly with respect to aneurysm-related outcomes. Prospective randomized clinical trials of small AAAs have used all-cause mortality (survival) as the primary end point and a diameter threshold of 5.5 cm for defining small aneurysms. Both the UK Small Aneurysm Trial3 and the Aneurysm Detection and Management (ADAM) trial4 found no survival advantage for early surgery compared with ultrasound surveillance. In the UK Small Aneurysm Trial, 5-year survival was 71% in the early surgery group and 62% in the surveillance group. This was not statistically different until late follow-up at 9 years, when survival was 53% in the early surgery group and 45% in the surveillance group 45%.22 The use of a 5.0-cm threshold to define small aneurysms and aneurysm-specific end points should be considered in future small aneurysm trials. Prospective randomized clinical trials comparing endovascular with open surgical repair have been conducted using different aneurysm size inclusion criteria. The Dutch Randomised Endovascular Aneurysm Management (DREAM) trial included patients with aneurysms at least 5.0 cm in diameter,7 and the Endovascular Aneurysm Repair (EVAR-1) trial used a 5.5 cm threshold to define large aneurysms.23 Both studies found a significant reduction in 30-day operative mortality with endovascular repair.7, 23 However, the early advantage of EVAR in operative mortality was not reflected in improved survival at 2 years24 or at 4 years,5 despite a persisting significant reduction in the aneurysm-related mortality rate at 4 years.5 The lack of a late survival advantage for endovascular repair has caused some to question its use for patients who are fit for open surgery6, 23 and others to question the usefulness of all-cause mortality as the primary end point with which to compare aneurysm treatment strategies.25, 26, 27 Our finding and that of others10, 28 that patients with the largest aneurysms have the least favorable long-term outcomes suggests the size distribution of aneurysms in a study cohort may be a major determinant of the ultimate outcome. Indeed, preoperative aneurysm size was a significant independent predictor of rupture, aneurysm related death, surgical conversion, and survival in Cox proportional hazard models. Whereas there were other predictors of survival, such as age, surgical risk, and peripheral occlusive disease, preoperative aneurysm size was the only factor that was predictive of the aneurysm-specific end point of rupture, AAA-related death, and conversion. This suggests that the aneurysm size group of 5 to 6 cm may be the most appropriate group to consider for long-term clinical trials evaluating different aneurysm treatment strategies or different endovascular devices. Such a selection criterion would provide access to the largest group of patients undergoing treatment and would exclude the smallest and largest aneurysms, which may distort the results for most patients. Despite the fact that patients with large aneurysms in this trial had less favorable outcomes than patients with small aneurysms, it should be noted that the outcomes of endovascular repair in patients with aneurysms ≥6.0 cm was, nonetheless, very good. Five years after endovascular repair, freedom from aneurysm rupture was 93%, and freedom from AAA related death was 92%, which is considerably better than the expected natural history for large aneurysms.1 These results are not dissimilar to the results of the EVAR-1 trial of good-risk patients with slightly smaller aneurysms (≥5.5 cm) which reported freedom from AAA-related death in 96% of patients 4 years after endovascular repair.5 Thus, endovascular repair is a good treatment option for suitable patients with both large and small aneurysms. Conclusions Preoperative aneurysm size is an important determinant of long-term outcome after EVAR. Patients with aneurysms <5.0 cm tend to be younger, better-risk patients with more favorable anatomy for EVAR. Patients with large aneurysms (≥6.0 cm) are older, at higher risk, and have less favorable aortic neck anatomy. Patients with small aneurysms had the most favorable long-term outcomes after EVAR, with no aneurysm ruptures, only one AAA-related death, and two surgical conversions. Large aneurysm patients have the shortest life expectancy and have a higher risk for aneurysm-specific adverse events such as rupture, surgical conversion, and aneurysm-related death. Nonetheless, EVAR is effective in preventing aneurysm rupture and aneurysm-related death in appropriately selected patients with small, medium, and large aneurysms. Author contributions Conception and design: CKZ Analysis and interpretation: CKZ, TC, DAB, FRA Data collection: CKZ, FRA, RAW Writing the article: CKZ Critical revision of the article: CKZ, DAB, FRA, KO Final approval of the article: CKZ, TC, DAB, FRA, KO, RAW Statistical analysis: TC, DAB Obtained funding: Not applicable Overall responsibility: CKZ References 1. 1Brewster DC, Cronenwett JL, Hallett JW, Johnston KW, Krupski WC, Matsumura JS. Guidelines for the treatment of abdominal aortic aneurysms (Report of a subcommittee of the Joint Council of the American Association for Vascular Surgery and Society for Vascular Surgery). J Vasc Surg. 2003;37:1106–1117. Abstract | Full Text |
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24. 24da Gama A. [Endovascular management of abdominal aortic aneurysm: a critical analysis on the DREAM, EVAR 1 and EVAR 2 randomized controlled trials]. Rev Port Cir Cardiotorac Vasc. 2005;12:99–103. MEDLINE 25. 25Zarins CK, Crabtree T, Arko FR, Heikkinen MA, Bloch DA, Ouriel K, et al. Endovascular repair or surveillance of patients with small AAA. Eur J Vasc Endovasc Surg. 2005;29:496–503. Abstract | Full Text |
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26. 26Heikkinen MA, Arko FR, Zarins CK. What is the significance of endoleaks and endotension. Surg Clin North Am. 2004;84:1337–1352. Full Text |
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27. 27Zarins CK, Heikkinen MA, Lee ES, Alsac JM, Arko FR. Short- and long-term outcome following endovascular aneurysm repair (How does it compare to open surgery?). J Cardiovasc Surg. 2004;45:321–333. 28. 28Ouriel K, Srivastava SD, Sarac TP, O’Hara PJ, Lyden SP, Greenberg RK, et al. Disparate outcome after endovascular treatment of small versus large abdominal aortic aneurysm. J Vasc Surg. 2003;37:1206–1212. Abstract | Full Text |
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a Division of Vascular Surgery, Stanford University, Stanford, Calif b Division of Health Research and Policy, Stanford University, Stanford, Calif c University of Texas, Southwestern Medical Center, Dallas, Tex d Department of Vascular Surgery, The Cleveland Clinic, Cleveland, Ohio e Division of Vascular Surgery, Harbor UCLA Medical Center, Torrance, Calif.  Reprint requests: Christopher K. Zarins, MD, Chidester Professor of Surgery, Stanford University Medical Center, Stanford, CA 94305-5450.
Competition of interest: The authors are consultants to the manufacturer of the endograft used in this study and may have received research support from the company. PII: S0741-5214(06)01368-1 doi:10.1016/j.jvs.2006.06.048 © 2006 The Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved. | |
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