NOTA CLÍNICA
Arteriovenous fistula of the renal pedicle after nephrectomy
Arzoz Fàbregas M*, Ibarz Servio L*,
Bayona Areñas S*, Bernal Salguero S*, Muchart Masaller J**, Saladié Roig JM*.
*Servicio de Urología. **Sección de Radiología
Vascular. Hospital Universitari Germans
Trias i Pujol. Badalona. Barcelona.
Actas Urol Esp. 2007;31(7):796-799
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ABSTRACT |
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ARTERIOVENOUS FISTULA OF THE RENAL PEDICLE AFTER
NEPHRECTOMY |
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Arteriovenous fistula or aneurysm of the renal pedicle after nephrectomy is a rare complication which is normally
diagnosed several years after the surgery. |
|
We present a case of arteriovenous fistula of
the right renal pedicle after a nephrectomy which
was performed 40 years ago because of pyonephrosis.
We assess the initial clinical report, the treatment and patient follow-up.
The current literature is also reviewed. |
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Key words: Arteriovenous fistula, Renal pedicle, Nephrectomy. |
There
are 3 types of renal arteriovenous fistula (RAVF):
congenital, idiopathic or acquired. Acquired fistulae are the most frequent and
they make up 75% of the RAVF. Among them, those after percutaneous
renal biopsy, renal trauma (either open or blunt trauma) and percutaneous renal surgery are the most frequent, whereas
those resulting from nephrectomy are rare, and even
rarer are those between the renal artery and vena cava1,2,3. We report
the case of a patient who had a fistula between the renal artery and vena cava
40 years after nephrectomy.
CASE REPORT
A
77 year-old patient who had underwent to a nephrectomy 40 years ago due to stone pyonephrosis
was admitted with a right flank pain together with a 1-month dysnea. A continuous thrill at the right flank was noticed
at auscultation during physical examination and a greater heart silhouette and
pulmonary hilius was observed at thorax radiography
(Fig.1). An angio-TC with multiplanar
reconstruction was asked for in an ambulatory way where a 3x2 cm diameter aneurismatic dilatation was observed at the distal end of
the right renal artery which opens into the inferior vena cava (Fig.2). A percutaneous embolization was
programmed on the basis of the diagnosis of an arteriovenous
fistula of the renal pedicle. The patient was admitted in the Emergency Room
two days before the procedure, due to a biventricular heart failure and
auricular fibrillation of uncertain chronology that led to an anticoagulant
treatment. A right renal arteriography was performed
once the heart failure was stabilised as well as the embolization
of the fistula with metallic stents, and the lack of arteriovenous shunt (Fig. 3-4) was checked. The patient was
clinically asymptomatic 24 hours later and there was no clinical recurrence
after a twelve-month follow-up.
FIGURE
1: Thorax Radiography: Increase of heart silhouette and both pulmonary hilius.
FIGURE
2: Abdominal TC with angio-TC reconstruction (Postero-anterior): 3x2 cm diameter aneurismatic
dilatation of the distal end of the right renal artery which opens into the inferior
vena cava.
FIGURE
3: Renal Arteriography: aneurismatic
dilatation of the right renal artery which opens into the inferior vena cava.
FIGURE
4: Renal Arteriography: Absence of shunt after arteriovenous embolization of the
fistula with metallic stents.
DISCUSSION
The
arteriovenous fistula or aneurysm of renal pedicle
after nephrectomy is a rare complication. Currently,
there are less than 100 cases reported in the literature and the renal artery
communicates with the inferior cava vein1,4 in less than 10. The formation of
this direct shunt between the arterial and venous system is thought to be
consequence of the ligation of the renal pedicle as a
whole with transfixing sutures, thus favouring that the venous and arterial
walls, in such a close contact, become necrotic with the consequent creation of
a fistula1,3.
Another independent risk factor for the formation of a postnephrectomy
fistula, is either the presence of an infectious process at the moment of the
surgery, such as tuberculosis or pyonephrosis, or postoperatory infections1,2,4-6 .Despite the fact
that the infection acts as an independent factor itself, it is believed that
the use of certain surgical suture materials, especially braided silk, can
store bacteria in those cases where the field is previously infected6. These fistulae are found at the right side in 70% of
the cases, since the vessels are shorter here, something which makes the
dissection of the different components of the pedicle more difficult to ligate them separately1,3,4. The arteriovenous shunt at the fistula creates a left-right
short-circuit, with a consequent increase in cardiac output. This situation
affects both ventricular cavities, leading to a cardiomegaly
and a congestive heart failure in the long term2,3.
The
majority of cases are diagnosed many years after the surgery1,4, although there are isolated
cases where the diagnosis was made during the first year of follow-up4,5. The mean time from the surgery to
the diagnosis of the fistula is estimated to be around 15 years1,3,5.
Clinical
manifestations vary depending on the time between the nephrectomy
and the diagnosis of the fistula2,4. Despite the fact that the presence of a continuos thrill at the flank or abdomen is associated with
this diagnosis, other symptomatic indications can be found when the
hypertension is refractory to the treatment or the presence of a congestic heart failure, which is the most important
complication of this entity which usually appears in late stages. In early
stages, the presence of a pulsatile abdominal mass,
flank pain or cardiac arrhythmia, along with a nephrectomy
background, should make us aware of the possibility of this entity2,7. The early
diagnosis allows the symptoms to be reversible after the treatment1.
The
diagnosis is basically clinical and tests such as the Doppler ultrasound, TC
or, especially the tridimensional tomography, help us
to confirm the diagnosis. Arteriography, and
sometimes the tridimensional tomography as well, are
crucial for both the diagnosis and the study of the fistula morphology
especially to decide which is the best therapeutic option4,7,8. Every
fistulae, especially the bigger ones, should be treated because of the risk of
heart failure and less frequently spontaneous aneurysmal
rupture4,9.
The proper treatment depends on the fistulae size and etiology.
The complete resection of the fistula, the single vein or artery ligation or the percutaneous embolization, are therapeutic approaches that have shown to
be effective for the treatment of this pathology4,9. In symptomatic small fistulae, percutaneous
embolization is the choice treatment, whereas the
excision would be performed in cases of greater arteriovenous
fistula where embolization fails. Single ligation is performed in cases of greater fistula in which
surgery is foreseen to be difficult due to the inflammation of the surrounding
tissue4.
The
percutaneous embolization,
although more advantageous than open surgery, is not free of complications.
Cases of migration of the agents to the pulmonary system (especially in the
bigger fistulae), renal or intestinal ischemia and fistula recurrence have been
reported. Different embolization techniques are
described in the medical literature so as to diminish the migration risk4,9,10.
The
excision surgery consists in isolating the lesion by means of the ligation of the vein and artery separately, before a
resection of the fistulous trajectory. When the surgery proves difficult, the
single ligation of the vessels can give good result
even though the recurrence rate increases4,11.
Therefore,
it is necessary to treat this pathology since both embolization
and surgery, performed alone or as combined approaches, are procedures which
allow us to approach these fistulae in a effective way, while avoiding the
possibility of heart failure or reverting it in those cases of early detection1,3,9,10.
CONCLUSION
Even
though RAVR is a rare entity, the presence of a arteriovenous fistula of the renal pedicle after a nephrectomy is a pathology that we have to take into
consideration when we face a patient with heart failure or abdominal thrill
along with the aforementioned backgrounds. Percutaneous
embolization is a less invasive and often curative
treatment, and the early treatment of the fistulae, at the moment of the
diagnosis, allows us to prevent serious consequence in the long run.
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Correspondence
author: Dra. Montserrat Arzoz Fàbregas
Servicio de
Urología. Hospital Universitari Germans
Trias i Pujol. Badalona.
Ctra. del Canyet, s/n - 08916 Badalona (Barcelona)
Tel.: 934
651 200
Author e-mail: 37031maf@comb.es
Paper information: Clinical notes
Manuscript received: july 2006
Manuscript
accepted: october 2007