Type:
Educational Exhibit
Keywords:
Stents, Image compression, Embolisation, Ultrasound, CT, Catheter arteriography, Musculoskeletal soft tissue, Arteries / Aorta, Aneurysms
Authors:
Y. Lamprecht1, E. GALLARDO AGROMAYOR2, E. Marín Diez1, E. Montes Figueroa1, V. Fernández Lobo1, E. YLLERA CONTRERAS3; 1Santander/ES, 2LIENCRES, CANTABRIA/ES, 3Burgos/ES
DOI:
10.1594/ecr2018/C-3142
Background
1) DEFINITION / PATHOPHYSIOLOGY:
A pseudoaneurysm (PSA) is considered a pulsatile encapsulated hematoma that is communicated with an artery whose wall is damaged by an inflammatory,
traumatic or iatrogenic cause.
Under the influence of sustained arterial pressure,
an interruption in the continuity of the wall occurs and blood dissects into the surrounding tissues through the damaged artery,
forming a perfused sac that communicates with the arterial light.
This sac may contain media or adventitia or be surrounded by soft tissues.
This differentiates a pseudoaneurysm from a true aneurysm,
the last one is histologically formed by all the arterial layers whereas a pseudoaneurysm lacks a complete arterial wall.
Fig. 1: True aneurysm (a) vs pseudoaneurysm (b). A pseudoaneurysm lacks a complete arterial wall whereas a true aneurysm is formed by all the arterial layers.
This vascular anomaly has a high risk of ruptures and a high morbidity rate.
Depending on their morphology,
they can be:
- Saccular (dilation along the transverse axis,
presenting a spherical shape and a small neck with the artery).
- Fusiform (dilation along the longitudinal axis).
Fig. 2: Pseudoaneurysm morphology. (a) Saccular with a dilation along the transverse axis. (b) Fusiform with a dilation along the longitudinal axis.
These anomalies can develop in different locations such as the arteries that supply the extremities or other arteries such as the carotid,
hepatic,
and splenic arteries.
2) ETIOLOGY:
There are different processes that can cause the formation of a pseudoaneurysm:
- Inflammation: pancreatitis [ Fig. 3 ],
peptic ulcer,
infection,
vasculitis (destruction of the media,
as it happens in Behçet's syndrome),
other causes [ Fig. 4 ].
- Tumor: osteochondroma,
neurofibromatosis,
leukemia and lymphoma,
choriocarcinoma.
- Trauma: liver,
kidneys,
pancreas and gastrointestinal tract,
etc.
[ Fig. 5 ]
- Atherosclerosis (due to the damage to the internal elastic lamina in atherosclerotic ulcers that can cause a rupture or an aortic dissection).
- Left Ventricle (LV) infarction (the free wall of the LV bothers the adjacent pericardium).
- Iatrogenic:
- Surgery.
[ Fig. 6 ]
- Biopsy.
- Drainage.
- Minimally invasive processes (catheterization).
[ Fig. 7 ]
- Transplant.
- Obstetric procedures.
- Placement of stents/grafts in true aneurysms.
[ Fig. 8 ]
3) SYMPTOMATOLOGY:
- Asymptomatic (incidental finding).
- Local symptoms (secondary to a mass effect on adjacent structures).
Palpable thrill,
audible bruit or pulsatile mass.
- Ischemia of the adjacent tissues (due to vascular compromise): it may end up producing necrosis of the skin and the overlying subcutaneous cellular tissue.
- Neurological symptoms (due to nerve compression or ischemia).
- The compression of the adjacent veins may lead to edema or Deep Venous Thrombosis (DVT).
Thromboembolism (TE).
- Rupture,
hemorrhage and potential shock.
Hemorrhage can have different manifestations depending on its location: sentinel bleeding from drainage or as hematemesis,
melena,
splenic rupture,
or subcapsular hepatic hematoma.
A pseudoaneurysm rupture can occur with spontaneous stabilization and subsequent circulatory collapse: the "double rupture" phenomenon.
4) EVOLUTION:
- Spontaneous thrombosis.
- Progression towards complication (infection,
local compression of neurovascular structures (they can produce a compartment syndrome) or rupture [ Fig. 3 ]).