Fig. 1. Ultrasound image shows a heterogeneous mass containing thrombus. Arterial flow was evident on the duplex image.				Fig. 2. Left brachial arteriogram confirms the presence of a large pseudoaneurysm. The outflow basilic vein of the arteriovenous fistula is compressed by the pseudoaneurysm and not visualized.
Case Reference No. CC-0298-06 This 44-year-old man had the recent onset of renal failure. A left brachial artery to left basilic vein arteriovenous fistula was created for dialysis access. Two weeks after the procedure, the patient developed an enlarging mass in the left arm, just above the elbow. An ultrasound examination revealed the mass to be a partially thrombosed pseudoaneurysm adjacent to the anastomosis (Fig. 1). Graded compression was attempted but was unsuccessful due to the aneurysm's short, broad neck. The referring vascular surgeon was not enthusiastic about operating on this patient again; the patient was a 550-lb Pickwickian man who tolerated procedures poorly. The vascular surgeon therefore requested that Tesio catheters be placed and the pseudoaneurysm be obliterated by any reasonable means. Because of table limit constraints, the patient was placed on a gurney alongside the angiography table with his left arm extended underneath the image intensifier. The outflow basilic vein was punctured under real-time ultrasound guidance since a pulse within the vein could not be palpated. A 4-F catheter was placed across the surgical anastomosis into the proximal brachial artery and an arteriogram was obtained (Fig. 2). This confirmed the presence of a pseudoaneurysm originating adjacent to the surgical anastomosis. The aneurysm was selectively catheterized (Fig. 3). An occlusion balloon catheter was inflated adjacent to the arterial defect to obstruct flow into the aneurysm (Fig. 4). A 3-F coaxial catheter was inserted through the occlusion balloon catheter, and approximately 500 U of thrombin was injected. The balloon was left inflated for approximately 5 minutes. Subsequently, this catheter was exchanged for a diagnostic catheter which was positioned within the brachial artery. A repeat arteriogram revealed residual contrast material within the aneurysm, but no evidence of continued extravasation (Fig. 5). A duplex evaluation on the following day confirmed successful occlusion of the pseudoaneurysm.				Fig. 3. A 5-F catheter is manipulated through the arterial defect into the pseudoaneurysm. Fig. 4. A 7-F occlusion balloon catheter is inflated within the aneurysm and retracted to block the arterial inflow. Fig. 5. Brachial arteriogram confirms successful occlusion of the aneurysm. Residual contrast material is present within the hematoma.
Under normal circumstances, this pseudoaneurysm would have been surgically repaired. The patient's body habitus and medical condition, however, made transcatheter occlusion an attractive alternative. Questions 1) What is the usual dose of thrombin for this application? 2) Is there a better way to manage this problem?