Is there a need for long term follow up after EVAR procedures?

Tratamentul endovascular (EVAR) a devenit intervenția predominantă pentru anevrismele aortei abdominale, oferind riscuri perioperatorii reduse comparativ cu chirurgia deschisă. Astfel, aceasta este cea mai eficientă și fiabilă metodă de tratament al AAA. Studiul nostru a evaluat 55 de cazuri elective de EVAR în două centre europene, monitorizate prin examene clinice și imagistică la intervale stabilite (perioada medie de follow-up: 18 luni). Datele din studiu au arătat că cea mai frecventă complicație este reprezentată de endoleak-ul de tip II (ce apare ca urmare a fluxului de sânge retrograd prin vase colaterale – cel mai adesea arterele lombare sau artera mezenterică inferioară, în sacul anevrismal, într-un procent de 13%, urmată de infecția la nivelul locului de acces (7%) și hemoragia (3%). Nu s-au observat cazuri de kinking, migrare a grefei, ruptură a anevrismului sau complicații sistemice în această serie. Reintervențiile au inclus extensia proximală endovasculară (11%), extensia pe un braț al endoprotezei (5%), embolizarea cu “coil” (7%) și o conversie chirurgicală deschisă (2%). Datele dintr-un sondaj integrat pe 246 de centre europene au relevat variații semnificative în protocoalele de urmărire, majoritatea bazându-se pe angio CT, peste jumătate utilizând și ecografia, iar puțin ecografia cu substanță de contrast (CEUS). Rezultatele susțin necesitatea unor protocoale structurate și adaptate riscului pentru supravegherea post-EVAR.
Complications following EVAR can include several important issues that may affect patient outcomes. One significant complication is the occurrence of endoleaks, where blood continues to flow into the aneurysm sac outside the graft, potentially causing continued aneurysm expansion. Stent graft migration can occur when the device shifts from its original placement, impacting its effectiveness. Kinking or occlusion of graft limbs may impede blood flow, risking limb ischemia. Component separation refers to parts of the stent graft disconnecting, which can also compromise aneurysm exclusion. More severe complications include rupture of the abdominal aortic aneurysm (AAA) and infection of the endograft itself. Additionally, some patients may develop renal failure as a complication related to the procedure or underlying vascular disease.

Endoleaks
Endoleaks are a notable complication following EVAR, with an incidence rate between 15 and 25 percent of patients within the first 30 days after the procedure. These endoleaks are frequently asymptomatic, which means they may not cause immediate symptoms and can go undetected without proper imaging surveillance. Endoleaks can be divided into several types according to their origin and nature. Accurate classification of endoleaks is essential, as it guides the appropriate clinical management and follow-up strategy used with EVAR patients.

Type II Endoleaks (EL)

Endoleaks occurring more than 30 days after the EVAR procedure are termed „late,” while those diagnosed after one year are considered „delayed.” These endoleaks typically feature low blood flow and generally follow a benign clinical course, meaning they do not usually cause immediate harm or require urgent treatment. Intervention is recommended only when there is evidence of aneurysm sac expansion, as this indicates a risk of rupture or further complications. It is important to recognize that endoleaks persisting for more than six months or those that recur can be associated with a higher incidence of adverse outcomes. This association has been described by Cochennec, emphasizing the need for careful surveillance and timely management when endoleaks do not resolve within a reasonable time frame.

Surveillance
Computed tomography angiography (CTA) is considered the gold standard imaging technique for surveillance after EVAR, as it provides detailed visualization of the aneurysm, stent graft, and potential complications. However, CTA is associated with several limitations, including significant costs, the risk of contrast-induced nephropathy, and radiation exposure. Other imaging methods such as Doppler ultrasound (DUS) and abdominal radiography (AXR) are also utilized in follow-up protocols. Contrast-enhanced ultrasound (CEUS), which uses microbubbles filled with sulphur hexafluoride (e.g., Sonovue, Bracco Diagnostics), offers a radiation-free and nephrotoxic-free alternative for endoleak detection. Additionally, magnetic resonance imaging (MRI) can be employed, especially in patients with contraindications to iodinated contrast, providing useful imaging without ionizing radiation.

E-Survey in Europe
The European Society of Vascular Surgery conducted a survey between April 2009 and January 2010 to collect data on European practice regarding EVAR follow-up. The study used a 15-question questionnaire to gather detailed information about the specific methods each center used to monitor patients after EVAR and to document the EVAR experience and protocols followed at those centers.
The survey included responses from participants representing 29 different countries and a total of 246 institutes. Across these centers, the median number of EVAR cases performed over a two-year period was 50, reflecting considerable experience and variability in procedural volume among the surveyed institutes.

Fig.1 Survey participants: 29 countries, 246 instiutes, including Romania

Materials and Methods
Data were gathered prospectively and entered into a vascular database from a total of 55 elective EVAR procedures performed at two centers: Army’s Center for Cardio-Vascular Diseases in Bucharest, Romania, and Praxis für Gefäß und Thoraxchirurgie (by Prof. Rolf Dammrau) in Duren, Germany. These cases spanned from 2008 to 2014. Patients underwent structured follow-up, with surveillance scheduled at 30 days, 6 months, and then annually. Monitoring was carried out through clinical examinations, as well as imaging with computed tomography angiography (CTA), duplex ultrasound (DUS), and contrast-enhanced ultrasound (CEUS). The mean follow-up period was 18 months.

Fig.2 CEUS examination + Power Doppler clearly showing the origin of the endoleak, the right iliac attachment site
The following table lists the types of devices used for EVAR, their manufacturers, and the number of cases for each:

Result – Complications
This table (4) indicates that the most frequent complication was Endoleak II (13%), followed by access site infections (7%), and hemorrhage (3%). No occurrences of kinking or stenosis, graft migration, AAA rupture, or systemic complications were reported in this series.

Re-interventions: Endovascular proximal extension was performed in six cases, accounting for 11% of patients requiring re-intervention. Endovascular leg extension was needed in three cases, representing 5% of the re-interventions. Four patients, or 7%, underwent endovascular coil embolization of side branches to manage complications. Conversion to open repair was necessary in one case, corresponding to 2% of the re-interventions. Mortality rate: There were no deaths related to abdominal aortic aneurysm (AAA) in this series. However, there was one death due to causes not related to AAA, corresponding to 2 percent of the patients.

Open repair after EVAR, also known as open surgical conversion, is a treatment option used when complications cannot be managed endovascularly. It involves the surgical removal or modification of the endovascular graft and replacement with a synthetic graft or homograft. This procedure is usually reserved for select cases such as symptomatic endoleaks that persist despite endovascular attempts, extensive migration of the graft, or aneurysm rupture. Open conversion is a major surgery typically performed when less invasive endovascular repairs are not feasible or have failed. It carries higher risks and is generally considered a last resort, particularly since many patients receiving EVAR are poor candidates for open surgery due to comorbidities or frailty.

Fig.4. Our book on the aortic pathologies published at Elsevier Editions in 2017,  with an international board of editors

Conclusions
EVAR has become the leading approach for treating abdominal aortic aneurysms, now accounting for approximately two-thirds of procedures, surpassing open repair in frequency. However, late complications after EVAR highlight the ongoing need for structured surveillance programs to monitor patient outcomes. Most centers rely on angio-CT scans, typically performed at one month, twelve months, and annually thereafter, as the primary follow-up method. More than half of centers also include ultrasound within their surveillance protocols, and a smaller number utilize contrast-enhanced ultrasound (CEUS) for more detailed assessment. Looking ahead, less invasive imaging techniques are expected to become routine in follow-up, though angio-CT remains the most widely used modality at present for monitoring EVAR patients.

Selective bibliography:
1. Tintoiu IC, Elefteriades JA, Ursulescu A, et al. New Approaches to Aortic Diseases from Valve to Abdominal Bifurcation. 1st ed. Elsevier; 2018. ISBN: 9780128099797.
2. Wanhainen A, et al. “ESVS 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-iliac Artery Aneurysms.” Eur J Vasc Endovasc Surg. 2024;67(2):161-271. [These European Society guidelines detail evidence and recommendations for post-EVAR follow-up];
3. Smith T, et al. “Imaging Surveillance After Endovascular Aneurysm Repair.” AJR Am J Roentgenol. 2020;214(3):517-525. doi:10.2214/AJR.19.22197. [Lifelong surveillance is recommended after EVAR due to ongoing risks of endoleak and graft failure];
4. Mazzei MA, et al. “Follow-up of endovascular aortic aneurysm repair.” World J Radiol. 2016;8(5):449-464. doi:10.4329/wjr.v8.i5.449. [Current guidelines recommend lifelong imaging after EVAR to detect complications and guide management];
5. Andraska EA, et al. “Longer follow-up intervals following EVAR are safe and effective in select patients.” J Vasc Surg. 2022;75(3):778-786. [Recent practice guidelines and investigation into risk-stratified, less intensive surveillance for low-risk patients];
6. Gonzalez RL, et al. “The importance of long-term follow-up after EVAR: A case report and literature review.” J Vasc Surg Cases, Innov Tech. 2022;8(1):1-5. [Case-based evidence and discussion on the value of attentive, ongoing follow-up];
7. Tinelli G, et al. “The sac evolution imaging follow-up after endovascular abdominal aortic aneurysm repair (EVAR).” J Vasc Surg. 2024;80(4):937-945. [International expert consensus on recommendations for follow-up after EVAR];
8. Farivar BS, Tracci MC. Evolving Follow-Up Protocols After EVAR: Toward Precision Surveillance. Endovascular Today. August 2025. Available online;
9. Özdemir-van Brunschot D, van Strijen MJ, Feddes B, van Sterkenburg SM, Wisselink W, de Vries JPPM, Fioole B, Zeebregts CJ. Factors Influencing Compliance to Follow-Up After Endovascular Aneurysm Repair. Vascular and Endovascular Surgery. 2023 Nov;57(8):880-887. doi:10.1177/15385744231183790. PMID: 37306151;
10. Geraedts ACM, de Mik S, Ubbink D, Koelemay M, Balm R; on behalf of the ODYSSEUS study group. Postoperative surveillance and long-term outcome after endovascular aortic aneurysm repair in the Netherlands: study protocol for the retrospective ODYSSEUS study. BMJ Open. 2020 Feb 18;10(2):e033584. doi: 10.1136/bmjopen-2019-033584. PMID: 32075831; PMCID: PMC7045090.