SCVIR - Case Club

Fig. 1. Pelvic arteriogram with the catheter positioned above the aortic bifurcation shows a large AVM supplied by both internal iliac arteries, with more contribution from the right side.

Fig. 2. Following transarterial Histoacryl embolization there is thrombosis and stasis in some of the feeders of the AVM (see arrow).

Case Reference No. CC-0101-05

A 62-year-old male was transferred to our institution for work-up of a 2-week history of paraplegia with a working diagnosis of a spinal arteriovenous vascular malformation (AVM). A pelvic arteriogram revealed a large AVM (see figure 1) supplied by both internal iliac arteries, with more contribution from the right side. The embolic agent chosen was N-butyl-cyanoacrylate (Histoacryl) diluted with Lipiodol. The patient had undergone 3 transarterial Histoacryl embolizations with a reasonable result (see figure 2) however, it was decided to perform a direct nidus injection in the operating room with direct vascular control. The patient was taken to the operating room for a laparotomy. Direct control of the AVM feeders and draining vessels was obtained and Histoacryl was directly injected into the feeding arteries. Following the direct embolization the patient's respiratory status deteriorated and he remained intubated. The chest X-ray (see figure 3) showed Histoacryl casts in the central pulmonary arteries.

Based on the deteriorating respiratory status, it was decided to attempt transcatheter Histoacryl pulmonary embolectomy. Via the right common femoral vein a 65 cm 8F introducer was placed at the IVC/RA junction and 7 F pigtail catheter was used to enter the main pulmonary artery. A pulmonary arteriogram was performed (see figure 4) which showed the Histoacryl casts. A Nitinol snare (Microvena) was used to grab the cast from the left pulmonary artery and then it was pulled to the IVC/right common iliac vein junction (see figure 5). The cast could not be withdrawn any further without breaking it off. It was decided to remove the cast surgically with a limited venotomy and removal of the embolus.

The patient was extubated and recovered. At 6 months of follow, MRA showed recurrence of the AVM.

Fig. 3. Plain chest X-ray shows Histoacryl casts in the central pulmonary arteries (see arrows).

Fig. 4. Pulmonary arteriogram was performed which confirmed the Histoacryl casts in the central pulmonary arteries (arrow points to the right central filling defect).

Fig. 5. Plain film of the pelvis shows large amounts of Histoacryl in the internal iliac arteries and AVM. The snare is seen around a large piece of Histoacryl (see arrow).

Questions:

What embolic agent is best for this type of lesion?
What route should be used to embolized this lesion: arterial, venous, direct nidus approach?
What is the mechanism for Histoacryl embolization?
What is the mechanism of lung injury with Histoacryl embolization?
Is Histoacryl FDA approved for this application?

References:
Kjellin IB, Boechat MI, Vinuela F, Westra SJ, Duckwiler GR. Pulmonary emboli following therapeutic embolization of cerebral arteriovenous malformations in children. Pediatr Radiol 2000 Apr;30(4):279-83.

Fig. 1. Pelvic arteriogram with the catheter positioned above the aortic bifurcation shows a large AVM supplied by both internal iliac arteries, with more contribution from the right side.	Fig. 2. Following transarterial Histoacryl embolization there is thrombosis and stasis in some of the feeders of the AVM (see arrow).
Case Reference No. CC-0101-05 A 62-year-old male was transferred to our institution for work-up of a 2-week history of paraplegia with a working diagnosis of a spinal arteriovenous vascular malformation (AVM). A pelvic arteriogram revealed a large AVM (see figure 1) supplied by both internal iliac arteries, with more contribution from the right side. The embolic agent chosen was N-butyl-cyanoacrylate (Histoacryl) diluted with Lipiodol. The patient had undergone 3 transarterial Histoacryl embolizations with a reasonable result (see figure 2) however, it was decided to perform a direct nidus injection in the operating room with direct vascular control. The patient was taken to the operating room for a laparotomy. Direct control of the AVM feeders and draining vessels was obtained and Histoacryl was directly injected into the feeding arteries. Following the direct embolization the patient's respiratory status deteriorated and he remained intubated. The chest X-ray (see figure 3) showed Histoacryl casts in the central pulmonary arteries. Based on the deteriorating respiratory status, it was decided to attempt transcatheter Histoacryl pulmonary embolectomy. Via the right common femoral vein a 65 cm 8F introducer was placed at the IVC/RA junction and 7 F pigtail catheter was used to enter the main pulmonary artery. A pulmonary arteriogram was performed (see figure 4) which showed the Histoacryl casts. A Nitinol snare (Microvena) was used to grab the cast from the left pulmonary artery and then it was pulled to the IVC/right common iliac vein junction (see figure 5). The cast could not be withdrawn any further without breaking it off. It was decided to remove the cast surgically with a limited venotomy and removal of the embolus. The patient was extubated and recovered. At 6 months of follow, MRA showed recurrence of the AVM.	Fig. 3. Plain chest X-ray shows Histoacryl casts in the central pulmonary arteries (see arrows). Fig. 4. Pulmonary arteriogram was performed which confirmed the Histoacryl casts in the central pulmonary arteries (arrow points to the right central filling defect). Fig. 5. Plain film of the pelvis shows large amounts of Histoacryl in the internal iliac arteries and AVM. The snare is seen around a large piece of Histoacryl (see arrow).
Questions: What embolic agent is best for this type of lesion? What route should be used to embolized this lesion: arterial, venous, direct nidus approach? What is the mechanism for Histoacryl embolization? What is the mechanism of lung injury with Histoacryl embolization? Is Histoacryl FDA approved for this application? References: Kjellin IB, Boechat MI, Vinuela F, Westra SJ, Duckwiler GR. Pulmonary emboli following therapeutic embolization of cerebral arteriovenous malformations in children. Pediatr Radiol 2000 Apr;30(4):279-83.
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