Abstract
We report the case of a large right renal arteriovenous fistula (AVF) in a 74-year old woman who presented with heart failure. Transthoracic echocardiography revealed normal left ventricular size and systolic function (ejection fraction 60–65%), moderately dilated right ventricle with severely depressed systolic function, and severe pulmonary hypertension. Right heart catheterization confirmed the elevated pulmonary pressures and showed a high cardiac output. Physical examination was remarkable for a right flank bruit. An abdominal ultrasound revealed an AVF originating from the distal right renal artery and dilated suprarenal inferior vena cava and hepatic veins. These findings were confirmed with an abdominal MRI. Percutaneous endovascular closure of the right renal AVF was successfully performed, with immediate reduction of pulmonary pressures and normalization of cardiac output. The patient’s symptoms improved, and a post intervention echocardiogram revealed normalization of right ventricular size.
Highlights
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Large renal AVFs can lead to a high cardiac output state and severe pulmonary hypertension.
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Non-invasive imaging is pivotal in the evaluation of patients with clinically suspected AVFs and in the choice of the most appropriate treatment modality.
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Endovascular treatment should be considered in cases in which renal function is preserved in the affected kidney, as surgery may be associated with loss of renal parenchyma.
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In the endovascular treatment of large AVFs, the presence of a high cardiac output increases the risk of distant coil embolization, and in select cases vascular occlusion plugs may be employed.
1
Introduction
Renal arteriovenous fistulas (AVFs) are rare findings . The majority of them are small intraparenchymal lesions secondary to renal biopsies or trauma. These AVFs are usually asymptomatic and tend to close spontaneously . However, AVFs can also occur as congenital malformations, in which case they tend to be large and result in hemodynamically significant left-to-right shunt, with venous and pulmonary hypertension and a high cardiac output (CO) state. Despite the technical advancements of endovascular therapy, the presence of a high CO often leads to failure of embolization procedures. Thus, the treatment of large renal AVFs remains based on various surgical approaches . However, because of concerns of the possible loss of renal parenchyma with surgery, in select cases endovascular treatment has been successfully performed . Here we describe a case of successful endovascular closure of a congenital large right renal AVF associated with high output heart failure (HF) and severe pulmonary hypertension. Importantly, follow up echocardiogram showed a significant reduction of right ventricular size and function and normalization of pulmonary artery pressures.
2
Case presentation
A 74-year old woman with a past medical history of essential hypertension, atrial fibrillation, precapillary pulmonary hypertension, and HF presented to our hospital with progressive dyspnea on exertion, orthopnea, lower extremity oedema, and abdominal swelling, which had not responded to increased intensity of diuretic therapy. She denied chest pain, light headedness, syncope, fevers, chills, and cough. She was a former smoker with a 15 pack-year history, but she had quit 40 years ago. She denied any alcohol or illicit drug use. She had no significant cardiac family history. On physical examination, jugular venous distension was noted; her lungs were clear to auscultation; a loud P2 and a 2-3/6 holosystolic murmur were heard; the abdomen was soft, mildly distended, with normal bowel sounds; a bruit was heard on the right flank; bilateral 1 + lower extremity oedema was present.
Upon admission, a transthoracic echocardiogram revealed a normal left ventricle (LV) with preserved systolic function (ejection fraction [EF] 60–65%); a moderately dilated right ventricle (RV) with severely depressed systolic function; systolic and diastolic flattening of the interventricular septum suggestive of RV pressure and volume overload; and severely elevated pulmonary artery pressure (PAP). A right heart catheterization (RHC) showed elevated PAP (80/30 mmHg) with a mildly elevated pulmonary capillary wedge pressure (15 mmHg) and a high CO (8.4 L/min). The pulmonary catheter was left in place, and she was admitted to the coronary care unit for continued invasive monitoring. Because of suspicion of an intra-abdominal shunt accounting for the abdominal bruit and the high CO state, an abdominal ultrasound was ordered. The test revealed the presence of an AVF originating from the distal right renal artery displacing the right kidney, and dilated suprarenal inferior vena cava and hepatic veins. These findings were confirmed with an abdominal MRI, which showed that the right renal AVF had a diameter of approximately 10 cm ( Fig. 1 ). A nuclear scan revealed intact renal perfusion bilaterally, albeit with a delay in the right kidney.
After completion of the diagnostic workup, the fistula was considered amenable to endovascular treatment. The patient underwent selective right renal angiography followed by closure of the AVF with placement of an Amplatzer 22-mm Vascular Plug II ( Figs. 2 and 3 ).
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