Aortocaval fistula is a rare and devastating complication of abdominal aortic aneurysm (AAA), wherein the aneurysm erodes into the inferior vena cava.
Spontaneous rupture of an abdominal aortic aneurysm into the adjacent inferior vena cava occurs in <1% of all aneurysms and in ~3% of ruptured aortic aneurysms 1.
The features can be very atypical leading to a delay in diagnosis. The various factors that influence the clinical presentations are the origin, size, location and duration of the fistula:
- high output cardiac failure
- bilateral pedal oedema (venous hypertension in the lower half of body)
- renal insufficiency (reduced renal blood flow)
- continuous bruit
Aortography is the modality of choice. Colour Doppler, CT and MRI may also demonstrate the same non-invasively. At times, the presence of a mural thrombus may obstruct the fistula.
Treatment and prognosis
Urgent surgical exploration and repair. Operative mortality of spontaneous aortocaval fistula is about 20 to 55%, figures being high predominantly due to delayed diagnosis or misdiagnosis.
- 1. Erratum. Therap Adv Gastroenterol. 2000;5 (3): 371. Therap Adv Gastroenterol (full text) - doi:10.1177/021849230000800321 - Free text at pubmed - Pubmed citation
- 2. Baker WH, Sharzer LA, Ehrenhaft JL. Aortocaval fistula as a complication of abdominal aortic aneurysms. Surgery. 1973;72 (6): 933-8. Pubmed citation
- 3. Steinke TM, Reber PU, Hakki H et-al. Haematuria and an abdominal aortic aneurysm-warning of an aortocaval fistula. Eur J Vasc Endovasc Surg. 1999;18 (6): 530-1. doi:10.1053/ejvs.1999.0940 - Pubmed citation
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