Early observations and pilot data that first suggested a new direction
Open surgical repair of abdominal aortic aneurysm (AAA) had been the standard since Dubost's first successful resection in 1951 and Creech's popularization of inline grafting. While effective, open repair carried 4-8% perioperative mortality and significant morbidity from the extensive surgical exposure. In 1991, Juan Parodi published the first series of endovascular aneurysm repair (EVAR), demonstrating that a stent-graft could be deployed through the femoral arteries to exclude the aneurysm sac without laparotomy. This proof of concept—treating major aortic pathology through small groin incisions—represented a potential revolution in vascular surgery, though early devices had high complication rates and limited applicability.
Landmark RCTs and pivotal trials that established the evidence base
Four landmark RCTs compared EVAR to open repair in the mid-2000s. The EVAR-1 trial (1252 patients) and the Dutch DREAM trial (351 patients) both demonstrated that EVAR had significantly lower 30-day operative mortality compared to open repair (1.7% vs 4.7% in EVAR-1; 1.2% vs 4.6% in DREAM). The OVER trial in the US VA system (881 patients) confirmed the short-term mortality advantage. However, these trials also revealed that the early survival benefit of EVAR was lost by 2-3 years due to ongoing aneurysm-related complications requiring reintervention. The EVAR-1 trial showed no long-term survival difference at 8 years, and graft-related complications and reinterventions were significantly more common after EVAR. These results established EVAR as superior for short-term outcomes but raised serious questions about long-term durability.
Follow-up studies, subgroup analyses, and real-world validation
Long-term follow-up of these trials reshaped the debate. The EVAR-1 15-year data published in 2018 showed that not only was the early survival advantage lost, but EVAR was associated with higher aneurysm-related mortality in the long term, primarily from endoleak and sac expansion leading to rupture. The OVER trial 14-year results similarly showed no long-term survival advantage for EVAR. Meanwhile, EVAR technology evolved dramatically with fenestrated and branched devices (F/BEVAR) extending endovascular options to complex aneurysms involving the renal and visceral arteries—anatomy previously treatable only by open surgery. The EVAR-2 trial examined EVAR in patients unfit for open repair and controversially showed no survival benefit over no repair, suggesting that some patients are too frail for any intervention.
Integration into clinical practice guidelines and recommendations
Current guidelines reflect the nuanced evidence. The SVS (Society for Vascular Surgery) 2018 guidelines recommend EVAR for patients with suitable anatomy and reasonable life expectancy, while acknowledging that open repair may be preferred in younger patients expected to outlive their endograft. The ESC/ESVS 2024 guidelines emphasize shared decision-making, noting that EVAR offers short-term perioperative advantages while open repair provides superior durability. Both approaches require lifelong surveillance. The guidelines also emphasize that repair of any type should be performed at high-volume centers, as institutional volume strongly correlates with outcomes.
Society for Vascular Surgery (SVS) Clinical Practice Guidelines
EVAR recommended for suitable anatomy with acceptable life expectancy; open repair preferred for younger patients or unsuitable EVAR anatomy; center volume >20 EVAR/year
ESC/ESVS Guidelines on the Diagnosis and Treatment of Aortic Diseases
Shared decision-making between EVAR and open repair considering anatomy, age, life expectancy, and patient preference; lifelong surveillance after EVAR mandatory
Now
Current standard of care and ongoing research directions
Despite the long-term equipoise in trial data, EVAR accounts for approximately 75-80% of elective AAA repairs in the US and UK, driven by patient preference for less invasive procedures and lower perioperative mortality. The tension between short-term EVAR superiority and long-term open repair durability remains unresolved. Next-generation endografts with improved sealing and durability are being evaluated. Complex EVAR (fenestrated and branched) has expanded the treatable anatomy but requires specialized expertise. Open surgical training is becoming a concern as fewer trainees gain adequate open aortic experience. Active research areas include patient-specific device selection using 3D modeling, bioresorbable stent-grafts, and risk prediction models to identify which patients will truly benefit from the lower perioperative risk of EVAR versus the durability of open repair.
Does EVAR provide a long-term survival advantage over open AAA repair?+
No. While EVAR reduces 30-day operative mortality by approximately 3% compared to open repair, this early survival advantage is lost by 2-3 years in all major RCTs (EVAR-1, DREAM, OVER). At 15 years, EVAR-1 showed higher aneurysm-related mortality after EVAR due to late endoleak and sac rupture. For patients with life expectancy >10 years, open repair may provide superior long-term outcomes, though this must be weighed against individual perioperative risk.
What is the reintervention rate after EVAR versus open repair?+
EVAR reintervention rates range from 15-25% over 10 years, primarily for endoleak (types I, II, and III), graft migration, and limb occlusion. Open repair reintervention rates are 5-10% over the same period, mainly for incisional hernia and graft infection. The need for lifelong CT surveillance after EVAR adds cumulative radiation exposure and cost. Newer devices have improved but not eliminated these reintervention requirements.
What anatomic criteria determine EVAR suitability?+
Standard EVAR requires an infrarenal aortic neck length >=10-15mm (device dependent), neck diameter <32mm, neck angulation <60 degrees, and adequate iliac access (diameter >7mm without severe tortuosity). Hostile neck anatomy (short, angulated, thrombus-lined, conical) is the primary reason for EVAR unsuitability and is associated with higher type Ia endoleak rates. Fenestrated EVAR has extended treatment to juxtarenal and suprarenal aneurysms but requires advanced planning and expertise.
Should AAA repair be centralized to high-volume centers?+
Yes. Multiple studies demonstrate a strong volume-outcome relationship for both open and endovascular AAA repair. Centers performing >20 EVAR and >10 open repairs annually have significantly lower perioperative mortality. This is reflected in guidelines from SVS, NICE, and ESVS that recommend centralization. In the UK, the National AAA Screening Programme has been associated with centralization and a reduction in operative mortality to <1% for elective EVAR.
