Randomized EVAR Trials and Advent of Level I Evidence: A Paradigm Shift in Management of Large Abdominal Aortic Aneurysms?

doi:10.1053/j.semvascsurg.2006.03.001

Seminars in Vascular Surgery

Volume 19, Issue 2, June 2006, Pages 69-74

https://doi.org/10.1053/j.semvascsurg.2006.03.001 Get rights and content

The recent endovascular aneurysm repair (EVAR) 1 and 2 and Dutch Randomized Endovascular Aneurysm Management (DREAM) trials addressed management of abdominal aortic aneurysms (AAAs) larger than 5.5 cm in diameter. The DREAM and EVAR 1 trials randomized patients appropriate for open repair between endovascular repair (EVAR) and open repair (OR), and the EVAR 2 trial randomized patients unfit for OR between EVAR and conservative nonoperative management (No Rx). The EVAR 1 trial showed a 3% lower initial mortality for EVAR, with a persistent reduction in aneurysm-related death at 4 years. Improvement in overall late survival was not demonstrated. Similarly, the DREAM trial observed an initial mortality advantage for EVAR, but overall 1-year survival was equivalent in both groups. Both trials found significantly higher complication and intervention rates and higher hospital costs with EVAR, and by 1 year a quality of life (QOL) benefit was not evident. The EVAR 2 trial did not demonstrate a survival advantage of EVAR with respect to nonoperative management, while noting that EVAR was associated with greater likelihood of treatment complications, subsequent interventions, and threefold higher costs. Both EVAR trials were limited by long delays between randomization and treatment. Moreover, 27% of patients in EVAR 2 crossed over from nonoperative to endovascular repair, and these patients had a lower procedure mortality from EVAR than those originally assigned to it (2% v 9%). These 47 cases, and the exclusion of 14 patients dying while waiting for EVAR, appears to confer a survival advantage to those receiving EVAR over those receiving no treatment in a post-hoc analysis, but per-protocol analysis of the EVAR 2 trial data performed by the EVAR investigators did not show a significant difference in either all-cause or aneurysm-related mortality. Thus, outcomes of the EVAR 2 trial have not settled the choice between EVAR and no treatment in this scenario to everyone’s satisfaction. In patients with large AAAs who are fit for OR, EVAR offers an initial mortality advantage over OR, with a persistent reduction in AAA-related death at 4 years. However, EVAR offers no overall survival benefit, is more costly, and requires more interventions and indefinite surveillance with only a brief QOL benefit. It may or may not offer a mortality benefit over nonoperative management in patients with large AAAs who are unfit for open repair, but the statistical significance of this comparison is inconclusive.

Section snippets

Review of the Status of EVAR Prior to Publication of Randomized Trials

Prior to publication of these European randomized trials, our information regarding EVAR came from institutional experiences, registry reports, and US Food and Drug Administration (FDA) device trials, particularly Phase II or pivotal trials of various devices conducted in the United States. The statistically significant advantages of EVAR over open repair (OR) established by these trials included (1) reduced cardiac and pulmonary morbidity, (2) decreased length of stay in the hospital and in

Recent Progress: An Improving Prospective

As one might expect with any new technology, the early years are full of problems, with first-generation devices falling by the wayside, and others withdrawn because of legal concerns or inadequate demand. Most current commercial endografts have been modified and new devices introduced in response to detected failure modes and perceived limitations of first-generation systems. In addition, newer devices have reduced profiles and their deployment systems have been improved. Adjunctive devices,

Indications for EVAR Before European Trials

Both the UK small AAA trial¹¹ and the Aneurysm Diagnosis And Management (ADAM) trial¹² failed to demonstrate a long-term survival advantage for early surgical intervention when compared with continued ultrasonography observation for small aneurysms in the range of 4 to 5.5 cm. These trials have reinforced conservative nonoperative management as appropriate for aneurysms of this size. A recent review of EVAR versus OR¹ concurred with these recommendations for small aneurysms, but also concluded

Dutch Randomized Endovascular Aneurysm Management Trial

The Dutch Randomized Endovascular Aneurysm Management (DREAM) trial was a multicentered randomized trial of EVAR versus OR, in which 351 patients were randomized with aneurysms larger than 5.5 cm. Patients were enrolled if considered fit for OR and had suitable anatomy for EVAR. Initial results were reported in 2004¹⁶ and revealed a 30-day mortality rate in favor of EVAR (1.2% EVAR v 4.6% OR). Two-year follow-up results were reported in 2005¹⁷ and demonstrated that all-cause mortality was not

EVAR 1 and 2 Trials

In the United Kingdom, two EVAR trials have been conducted in which patients were enrolled with large AAAs with suitable anatomy for EVAR. In the EVAR 1 trial,¹⁸ like the DREAM trial, patients with large (>5.5 cm) AAAs who were considered fit for surgery were randomized between EVAR and OR. Of the 4,799 screened patients, 22 refused enrollment, 273 dropped out during evaluation, 286 were eliminated because of missing computed tomography data, and 313 had AAAs less than 5.5 cm. Significantly,

Impact of Trials on AAA Management

How should these trials affect the process of deciding between endovascular, OR, and conservative management? First, these trials apply to only two of the four large aneurysm categories. Specifically, patients who may or may not be suitable for open surgery, but who have a large aneurysm and are anatomically appropriate for EVAR. OR for those with a large aneurysm who are fit for surgery but have unsuitable anatomy for EVAR goes unchallenged. Management of those patients who are high risk for

Conclusions

It is heartening to have level I evidence to assist in decisions regarding the application of EVAR and we should be grateful to our European colleagues and their healthcare systems for carrying out these studies. The climate in the United States, with patients exposed to so much hype for EVAR almost precludes proper randomized trials, as has been the case for device-specific FDA trials. Nonetheless, even level I evidence should be examined closely, to determine if it draws valid conclusions and

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Cited by (32)

Prospective nonrandomized study to evaluate cone beam computed tomography for technical assessment of standard and complex endovascular aortic repair
2020, Journal of Vascular Surgery
The objective of this study was to analyze the utility of cone beam computed tomography (CBCT) for technical assessment of standard and complex endovascular aneurysm repair (EVAR).
Data of consecutive patients who underwent standard or complex EVAR in 2016 and 2017 at our institution were entered into a prospective database and analyzed retrospectively. There were 154 patients (126 male; mean age, 74 ± 8 years) enrolled in a prospective study between 2016 and 2017. A total of 170 aortic procedures were investigated, including 85 fenestrated-branched EVARs (F-BEVARs), 42 abdominal and thoracic EVARs, 32 EVARs with iliac branch devices, and 11 aorta-related interventions. Technical assessment was done using CBCT with and without contrast enhancement, digital subtraction angiography (DSA), and computed tomography angiography (CTA). Patients with stage 3B or stage 4 chronic kidney disease had CBCT without contrast enhancement. Radiation exposure (mean dose-area product), effective dose (ED), and amount of iodine contrast agent were analyzed. End points were presence of any endoleak, positive findings warranting possible intervention (stent kink or compression, type I or type III endoleak, dissection, thrombus), and need for secondary intervention.
Radiation exposure and amount of iodine contrast agent were significantly higher (P < .05) for F-BEVAR compared with other aortic procedures (174±101 Gy∙cm² vs 1135±113 Gy∙cm² and 144±60 mL vs 122±49 mL). ED averaged 74±36 mSv for the aortic procedure, 18 ± 18 mSv for fluoroscopy, 7 ± 7 mSv for DSA acquisition, 15±7 mSv for CBCT, and 34±17 mSv for CTA imaging (P < .001). Endoleak detection was significantly higher (P < .001) with CBCT (53%) compared with DSA (14%) and CTA (46%). CBCT identified 52 positive findings in 43 patients (28%), higher for F-BEVAR compared with other aortic procedures (35% vs 16%; P = .01). Positive findings included stent compression or kink in 29 patients (17%), type I or type III endoleak in 16 patients (10%), and arterial dissection or thrombus in 7 patients (5%). Of these, 28 patients (18%) had positive findings that prompted an intraoperative (17%) or delayed intervention (1%). Another 15 patients (10%) with minor positive findings were observed with no clinical consequence. DSA alone would not have detected positive findings in 34 of 43 patients (79%), including 21 patients (49%) who needed secondary interventions. CTA diagnosed two (1%) additional endoleaks requiring intervention (one type IC, one type IIIC) that were not diagnosed by CBCT. Replacing DSA and CTA by CBCT would have resulted in 53% ± 13% reduction in amount of iodine contrast agent and 55% ± 12% reduction in ED (P < .05).
CBCT reliably detected positive findings prompting immediate revisions in nearly one of five patients, with the highest rates among F-BEVAR patients. Detection of any endoleak was higher with CBCT compared with DSA or CTA, but most endoleaks were observed. DSA alone failed to detect positive findings warranting revisions.
Predictors of percutaneous access failure requiring open femoral surgical conversion during endovascular aortic aneurysm repair
2013, Journal of Vascular Surgery
To determine predictors of percutaneous (PEVAR) access failure requiring conversion to an open approach (OEVAR) during endovascular aortic aneurysm repair (EVAR).
A single-center retrospective review of all EVAR patients from January 2009 through June 2011 with multivariate analysis of clinical and anatomic variables that could impact access outcome was conducted. Target vessel calcification was categorized as mild, moderate, or severe based on circumferential calcium arc (<⅓, ⅓ to ½, and >½ respectively), dyslipidemia (defined as low-density lipoprotein >130 mg/dL or receiving lipid lowering medication), and obesity (defined as body mass index [BMI] >30).
We investigated 400 access sites for 200 patients who underwent EVAR. The study cohort's characteristics included an average age of 72.8 ± 9.0 years, vessel size of 9.6 ± 1.8 mm, sheath size of 17.1 ± 3.0 Fr, BMI of 27.6 ± 5.3, and estimated glomular filtration rate of 68.5 ± 24.2 mL/min. Comorbidities included dyslipidemia in 129 patients (64.5%) and diabetes in 54 patients (27%). There were 132 OEVAR (66 patients), two mixed OEVAR with contralateral PEVAR (one patient), and 266 (133 patients) PEVAR approaches. Use of PEVAR increased over time (45.5% [2009], 77.8% [2010], and up to 88.5% [2011]; P = .001) while conversions decreased (24.3% [2009], 8.7% [2010], and 4.3% [2011]; P = .001]. More OEVAR patients (35.8%) stayed longer than 3 days compared with 21.1% for PEVAR (P = .028). For the 266 PEVAR approaches, 32 access sites (12.0%) had to be converted. Severely calcified arteries were most predictive of conversion (odds ratio [OR], 36.4; P < .001). Year of procedure (2010; OR, 0.17; P = .001; 2011, OR, 0.20; P = .049), female gender (OR, 3.1; P = .017), moderately calcified arteries (OR, 2.5; P = .085), and age (OR, 2.3 [per decade]; P = .002) were all also significant. Vessel size, sheath size, and BMI were found to be nonsignificant predictors of conversion.
PEVAR was found to be safe, reliable, and feasible. Several factors, including learning curve, vessel calcification, age, and female gender predicted conversion of PEVAR to OEVAR.
Debate: Whether level i evidence comparing thoracic endovascular repair and medical management is necessary for uncomplicated type B aortic dissections
2013, Journal of Vascular Surgery
Citation Excerpt :
Thus, we are lacking reliable information on the survival of patients with type B dissections. Endovascular repair is a well-known alternative to open repair for the treatment of abdominal aortic aneurysm supported by the two initial European prospective randomized trials (Dutch Randomised Trial on Endovascular Versus Open Aneurysm Repair [DREAM], Endovascular Aneurysm Repair [EVAR]).18-20 Accordingly, but despite the lack of RCT, the use of stent grafts has been introduced to and reported favorable in thoracic aortic aneurysms and in traumatic thoracic aortic ruptures.21-23
Type B aortic dissections continue to be one of the most challenging clinical scenarios confronting vascular surgeons. In the era of open surgery, the therapeutic options were limited to medical management of hypertension and large open thoracoabdominal operations. In the current endovascular era, the operative strategies have become less invasive but the questions regarding therapeutic approaches have become more numerous and complex. In patients with acute uncomplicated type B aortic dissections, we are still unsure as to which patients are best treated with medical therapy alone or with the addition of early endovascular repair. Data from single centers and registries have provided some guidance; however, questions remain. Perhaps level 1 evidence from well-designed randomized controlled trials will answer all of our questions. This is the topic of the current debate.
Part one: For the motion. Level 1 evidence is necessary comparing TEVAR and medical management of uncomplicated type B aortic dissection
2013, European Journal of Vascular and Endovascular Surgery
Citation Excerpt :
Thus, we are lacking reliable information on the survival of patients with type B dissections. Endovascular repair is a well-known alternative to open repair for the treatment of abdominal aortic aneurysm, supported by two initial European prospective, randomized trials (Dutch Randomised Endovascular Aneurysm Management [DREAM], Endovascular Aneurysm Repair [EVAR]).18–20 Accordingly, but despite the lack of RCTs, the use of stent grafts has been introduced, and have been reported to be favorable in thoracic aortic aneurysms and in traumatic thoracic aortic ruptures.21–23
Surgical Treatment of Abdominal Aortic Aneurysms
2013, Vascular Medicine: A Companion to Braunwald's Heart Disease: Second Edition
Risk attitude and preferences in person's hypothetically facing open repair of abdominal aortic aneurysm
2012, Journal of Vascular Nursing
Citation Excerpt :
The current evidence on morbidity, mortality and HRQL favors EVAR in the short term, but the long-term evidence shows small differences between OR and EVAR.31,32 The evidence is not clearly in favor for either treatments because long-term results for EVAR are lacking; it is suggested that each patient should get individualized information, and the informed patient should contribute to the decision.33,34 To facilitate decision making, it is also important to consider earlier experiences that may influence preference for treatment.35,36
The aim of this study was to describe risk attitude and preference for treatment using a proxy measurement of a general population sample hypothetically facing treatment for open repair (OR) of abdominal aortic aneurysm (AAA). In a telephone interview, a standard gamble (SG) and a time trade-off (TTO) question were asked to elicit risk attitude and preference for treatment in a general population sample of 200 persons, stratified in four age groups. When facing the two questions of (1) either live a shorter life without an AAA compared to a longer life with an AAA (TTO) or (2) taking a risk of living with AAA compared to taking the risk with surgical treatment (SG), the oldest age group was neither willing to live a shorter life without AAA, nor willing to take a risk with surgical treatment to the same extent as the younger age groups: age 50–59 (TTO P = 0.03, SG P = < 0.001), age 60–69 (TTO P = 0.01, SG P = < 0.001), age 70–79 (TTO P = 0.02, SG P = 0.002). These results suggest that persons in the age groups over 80 years old in the general population sample are more inclined to go on living with an AAA without taking the immediate risk associated with OR as well as the postoperatively impaired health-related quality of life (HRQL). Preference for treatment in different age groups is important to consider during the decision-making process, especially for patients over 80 years old. Patient education about treatment options, specific risks as well as postoperative impairment of HRQL is necessary in this process.

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Randomized EVAR Trials and Advent of Level I Evidence: A Paradigm Shift in Management of Large Abdominal Aortic Aneurysms?

Section snippets

Review of the Status of EVAR Prior to Publication of Randomized Trials

Other Problems Limiting Acceptance of EVAR

Recent Progress: An Improving Prospective

Indications for EVAR Before European Trials

Dutch Randomized Endovascular Aneurysm Management Trial

EVAR 1 and 2 Trials

Impact of Trials on AAA Management

Conclusions

J Vasc Surg

J Vasc Surg

J Vasc Surg

J Vasc Surg

J Vasc Surg

J Vasc Surg

J Vasc Surg

J Vasc Surg

Lancet

Ann Vasc Surg

Health-related quality of life outcomes following elective open or endovascular AAA repairA randomized controlled trial

J Endovasc Ther

An update on the important findings from the EUROSTAR EVAR registry

Vascular