Renal AVF is a rare lesion. It might be acquired, idiopathic or congenital. The most common form is the acquired form and is a result of interventional procedures such as renal biopsy, percutaneous nephrostomy, partial nephrectomy and surgery. The acquired form is also due to tumor, trauma and inflammatory disease. Our patient had a history of cesarean section 5 months before starting symptoms so there can be a possibility of those categories. The congenital form is the rarest one and has angiomatous or cricoid formation. The idiopathic form is used to explain those forms in which the etiology is undetermined (2, 4, 5, 8).
Renal AVF is more frequent in right kidney, in women and in ages 30 to 40 years. Our patient was a woman but she was 54 years old and had involvement of left kidney (3).
Hematuria is the most frequent symptom of renal AVF. Other clinical appearances include wide pulse pressure, abdominal bruit, and mild tachycardia, heart failure, left ventricular hypertrophy, hypertension, renal failure and abdominal pain. Our patient was suffering from hematuria at her first presentation and she also had abdominal bruit, tachycardia, signs and symptoms of heart failure, left ventricular hypertrophy, grade 1 hypertension and abdominal pain (2, 3, 9).
Renal AVF can affect heart structure due to volume overload and high-output condition. It’s effect is eccentric left ventricular hypertrophy and heart failure (10). Hypertension creates concentric left ventricular hypertrophy (9). Our patient had left ventricular hypertrophy due to renal AVF. In renal AVF, hypertension arises owing to a renal parenchymal hypoperfusion distal to the fistula with increment renin secretion (2, 6). Treatment of renal AVF eventuates in decrement in LVEDD and LVMI (10). Management of high blood pressure for example with eliminating the underlying cause can lead to regression of LVH (9). In our patient LVEDD, LVMI and left ventricular wall thickness (LVWT) decreased. Decreasing in LVEDD and LVMI was due to treatment of renal AVF and decrease in LVWT might have been due to high blood pressure control. The result of renal AVF closing on left ventricular ejection fraction (LVEF) is controversial (10). In our patient LVEF increased from 40% to 50% about 6 months after treatment.
There are several modalities for diagnosis of renal AVF includes magnetic resonance imaging (MRI), computed tomography (CT), duplex ultra-sonography (DUS) and digital subtraction angiography (DSA). The gold standard modality for assessment of renal AVF is DSA. DUS is very efficient for diagnosis and is very useful in the follow-up after percutaneous intervention or surgery. We used CT scan for primary diagnosis of renal AVF in our patient and then we used DSA for certain diagnosis and management. For follow-up we used DUS for evaluation of patency of the previous renal AVF (1-3).
The treatment is usually performed for symptomatic patients. Some important indications for treatment are heart failure, hypertension, persistent or recurrent hematuria and increment in the extent of renal AVF in follow-up. Our patient had hypertension and symptoms and sings of heart failure (3, 4, 6).
There are two kinds of treatments for renal AVF include surgery and endovascular management. Endovascular management is the choice therapy even for large or high-flow renal AVF Due to the fact that not only it preserves renal function, but also it is minimally invasive and low risk. Large and high-flow renal AVFs have risk of pulmonary or systemic embolization so if there is fear for these problems surgery is preferred over endovascular treatment. Unfavorable anatomy for endovascular management is also an indication for surgery. Among endovascular procedures coil embolization is often used. For small fistulas embolization with methyl cyanoacrylate glue may be useful. In our patient due to large AVF and favorable anatomy for endovascular treatment, coil embolization with VSD coil was done (1, 4, 5, 7, 8).
Although renal artery embolization is a safe intervention, some complications may occur such as dissection or perforation of vessels, groin hematoma, coil migration, pulmonary or systemic embolization, renal failure, post embolization syndrome and infection (1, 4, 7).
3.1. Conclusion
Renal AVF should be considered as a differential diagnosis in patients with urinary complaints (especially hematuria) and indeterminate abnormalities in the urinary system. The gold standard modality for assessment of renal AVF is DSA and when the noninvasive data are non-diagnostic we can have a definite diagnosis with DSA. Endovascular management (coil embolization in most cases) is the best treatment and it is safe but it may have some complications especially in high-flow and large renal AVFs.
LEAVE A COMMENT HERE: