CASE 17216 Published on 25.03.2021

Pitfalls in EVAR evaluation


Interventional radiology

Case Type

Clinical Cases


Leonardo Teodoli, Bianca Rocco, Livia Marchitelli, Mario Corona, Mario Bezzi, Carlo Catalano


86 years, female

Area of Interest Arteries / Aorta, Cardiovascular system, Emergency, Interventional vascular ; Imaging Technique Catheter arteriography, Cone beam CT, CT
Clinical History

A 86 years-old female patient complaining abdominal pain was admitted to our hospital. An angio-CT showed a dissected abdominal aneurism with signs of impending rupture. Vascular surgeons deployed an aorto-iliac endoprosthesis. Five days after EVAR the patient showed signs of acute right heart failure and angio-CT was performed.

Imaging Findings

Contrast-enhanced CT was performed (100 mL of nonionic contrast material 370 mg of iodine/mL, flow rate of 3.5 mL/sec).

A high flow endoleak was appreciable in arterial phase with no clear leak coming from the proximal neck (excluding type Ia). Endoleak was connected to the lumbar arteries and compressed inferior cava vein showed early enhancement in arterial phase (Fig1 a-b).

Angiography and intraprocedural Cone Beam-CT demonstrate a type II endoleak (via lumbar arteries) with an aortocaval fistula (Fig 2 and 3).

The sac, reached with right retrograde catheterization parallel to the iliac limb, was embolized by detachable coils and non-adhesive liquid embolization material. Once the fistula was excluded, circulation within the sac was fed by the lumbar artery, flowing out towards inferior mesenteric artery.  The arc of Riolan was used to embolised with coils the IMA origin, not reachable by the sac (Fig4). Final angiography confirmed embolization of aneurysmal sac (Fig5).


Background Spontaneous aortocaval fistula (ACF) is a rare complication of abdominal aortic aneurysm rupture (3 to 6 % of the patients [1, 2]). Usually, fistula is located in the right posterolateral portion of the aortic aneurysm and communicates with the IVC at the level of its bifurcation or immediately above [3].

Early diagnosis and intervention can double survival rates from 25% to 50% [1, 4, 5]. Therefore, high index of suspicion is important for the clinician to early diagnose and treat this life-threatening emergency.

Clinical Perspective Clinical presentation of ACF is heterogeneous including high output cardiac failure, bilateral peripheral oedema, acute kidney failure and hematuria [6, 7].

Symptoms associated with aneurysm rupture include back or abdominal pain and acute shock.

Imaging Perspective The diagnostic gold standard for ACF is CT scan, which can show an early enhancement of the inferior vena cava (IVC), with or without the visualization of the fistulous communication. Unfortunately quite often the aneurysm compresses the IVC, with difficult evaluation of the IVC early enhancement. In these cases, synchronous opacisation of the iliac veins and renal veins suggest  ACF, but it is necessary to perform an arteriography in order to confirm and treat ACF. Appropriate CT protocol consists of pre-contrast scan and a set of early-phase scans followed by a single venous phase acquisition. Eighty mL of nonionic iodinated contrast material must be injected at a flow rate of 4 mL/sec through an 18-gauge antecubital intravenous line. Dynamic CT angiography series is initiated with bolus-tracking measurement in the abdominal aorta at a threshold of 90 HU [8].

Recently, 4-Dimensional Flow-Sensitive MRI has been proposed for the assessment of hemodynamic analysis of aortocaval fistula, but further data are necessary to confirm its appropriateness [9].

Outcome The primary aim for patient suffering from ACF is to reduce the fistula flow to stabilize the hemodynamic status [10].

Different materials can be used to embolize ACF during endovascular procedure depending on flow and anatomical vascular architecture, including glue, coil and vascular plug. Another option to exclude the fistula is stent-grafting [11–14].

Take-Home Message/Teaching Points Aortocaval fistula is a rare complication of ruptured abdominal aortic aneurysm.

Aortocaval fistula in ruptured abdominal aortic aneurysms are often diagnosed with angio-computed tomography scan, however, in some cases, aortography is necessary.

Endovascular procedure using embolic agents or stent-grafting is a treatment option to exclude aortocaval fistula.

Written informed patient consent for publication has been obtained.

Differential Diagnosis List
High flow type II endoleak associated with aortocaval fistula.
Type-II endoleak
Abdominal aortic dissection
Abdominal aortic aneurism infection
Extracavity ruptured abdominal aortic aneurysm
Aorto-left renal vein fistula
Final Diagnosis
High flow type II endoleak associated with aortocaval fistula.
Case information
DOI: 10.35100/eurorad/case.17216
ISSN: 1563-4086