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The lack of any presence of endoleak at the initial imaging after endovascular aortic aneurysm repair (EVAR) is predictive of good midterm outcomes with less need for reintervention. As such, patients with negative endoleak results at first follow-up can be prescribed less rigorous monitoring than those who screen positive for endoleak, according to an article published online April 14, 2014, ahead of print in the Journal of Vascular Surgery.

Data from the paper were previously presented at the annual meeting of the Canadian Society for Vascular Surgery in September 2013.

Oren K. Steinmetz, MD, of the McGill University Health Centre (Montreal, Canada), and colleagues reviewed prospectively collected data on 134 patients treated with elective EVAR for infrarenal abdominal aortic aneurysms at a single center from 2004 to 2009.

Median maximum diameter before repair was 55.3 mm (IQR 51.4-61.6 mm), and several different configurations and grafts were used during EVAR:

• Talent (64.2%; Medtronic; Minneapolis, MN)
• Zenith (17.2%; Cook; Bloomington, IN)
• Endurant (17.2%; Medtronic)
• Aorfix (1.5%; Lombard Medical; Didcot, United Kingdom)

Initial follow-up with computed tomography (CT) occurred a median 19 days postprocedure (IQR 8.5-34 days), followed by screening with CT or duplex ultrasound (often used when first screening was negative for endoleak, especially during the latter half of the study).

Currently, the Society for Vascular Surgery guidelines recommend that CT scans be performed at 1 month and 1 year then annually thereafter.

Most Patients Have No Endoleak

Eighty percent of patients (n = 107) had no endoleak at initial postprocedural CT. There were no differences in comorbidities or anticoagulation status between those with or without endoleaks.

Of the 107 patients without endoleak at initial CT scan, 11 (9.3%) underwent reintervention at a mean 30 months after EVAR, though endoleak was responsible for only 4 (3.7%) of the subsequent interventions. Of those with evidence of endoleak at first follow-up, 11 patients (37%) underwent a reintervention at a mean 8.5 months; seven of the procedures were to treat endoleak. Reinterventions unrelated to endoleak occurred because of thrombotic complications, infectious complications, and groin pseudoaneurysms.

Kaplan-Meier curves estimated that, over 8 years, patients with positive initial postprocedural CT scans were much more likely to need either all-cause reintervention or endoleak-related reintervention. Cox univariate analysis confirmed these results (table 1).

Table 1. Risk of Reintervention: Initial Scan Positive vs Negative for Endoleak

No ‘Gold Standard’ in Screening Modality, Timing

The results fall into line with previous studies, the authors say. Frank A. Lederle, MD, of the Veterans Affairs Medical Center (Minneapolis, MN) agreed, telling TCTMD in an email, “There have been many case series reporting that patients who have favorable findings on early follow-up imaging (ie, absence of endoleak, AAA shrinkage, etc) are at lower risk of needing future intervention and therefore may be candidates for less or no follow-up.”

Steinmetz and colleagues write that reintervention is not only less common after a negative first scan, it also tends to occur much later. Where debate still exists, according to the authors, is in determining the ‘gold standard’ of ideal screening modality and regimen. Though very useful at identifying endoleaks and aortic anatomy, CT angiography also increases exposure to radiation and contrast material and is expensive, they say, adding that “there is still a paucity of evidence, and recent studies suggest significant heterogeneity in use among vascular surgeons.”

Although “the initial follow-up indications reflected caution regarding a new procedure and early devices with higher complication rates,” Dr. Lederle stated, “I think less follow-up based on early predictors is justifiable and likely to become widespread, though ideally any new recommendations would take all such studies into account rather than being based on any 1 study.”

A lack of strict follow-up is a limitation noted by both the investigators of this particular study (roughly 15% of patients did not receive adequate follow-up) and Dr. Lederle in regards to general practice. “Patients who should be followed up probably aren’t because adequate call-back programs are lacking,” Dr. Lederle said.

Study Details

Median patient age was 78 years, 84% were male, and common comorbidities included hypertension (80%), hyperlipidemia (62%), and type 2 diabetes (16%).

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