Category: Interventional Radiology, Region: Thorax-Vessels, Plane: Other
Background: Congenital arteriovenous malformations (AVM) of the left internal mammary artery (LIMA) are exceptionally rare. Patients typically present with continuous precordial murmurs and may have an associated pulsatile chest mass. Here we describe a case of a congenital AVM originating from the LIMA which was successfully embolized with n-butyl cyanoacrylate (NBCA) using a transcatheter arterial approach. Case and Technique: A 9-year-old boy presented with a pulsatile mass of the left chest wall [Figure 1]. CT angiogram revealed an AVM arising from the LIMA involving the left internal mammary vein (LIMV) [Figure 2]. The decision was made to embolize the lesion. The right common femoral artery was accessed using micropuncture technique and ultrasound guidance. A standard 0.035” guidewire was placed followed by a 5 Fr sheath, and an aortogram was performed. Next the left subclavian artery was selected. Digital subtracted angiogram showed the AVM arising off the LIMA with immediate filling of the LIMV [Figure 3a]. The LIMA was selected with a 2.4 Fr Progreat microcatheter and 0.018" GT guidewire, which were navigated beyond the AVM. A 2 mm micronester coil was placed to prevent glue from migrating into the abdomen. The AVM was then embolized using TRUFILL n-Butyl cyanoacrylate glue (NBCA) and lipiodol mixed in a 1:3 ratio. Repeat angiogram following embolization showed no further filling of the AVM [Figure 3b]. There were no complications related to procedure. A follow-up CT angiogram performed 1 month post-procedure demonstrated that the AVM was completely treated [Figure 4]. The patient returned to clinic for follow-up, at which time the treated mass had resolved and there was no further precordial murmur. Discussion and Teaching Points: AVMs in this location pose a risk of enlargement, rupture, infection, or high-output cardiac failure, warranting early intervention. In our patient, concerns for complications were amplified because the lesion had steadily increased in size over one year. Open surgical approaches for chest wall AVM repair are associated with high morbidity and surgical risk, whereas endovascular embolization is less invasive, with improved visualization under fluoroscopic guidance. Transcatheter embolization techniques are widely considered safe, effective, and easy to perform. However, it is essential to obtain follow-up CT angiograms due to risk of potential recanalization of treated vessels. AVM embolization in this patient was feasible and safe, while avoiding risks and morbidity associated with open surgical repair. Fig. 1. 9 year old male presented to Interventional Radiology (IR) clinic with a pulsatile left chest wall mass. Fig. 2. Given the patient’s constellation of history and physical exam findings, a CT scan was obtained which demonstrated an arteriovenous malformation (AVM) arising off the left internal mammary artery. A 3D rendered image of the CT scan delineates the extent of the AVM. Fig. 3a. The patient was brought to the IR suite for angiogram and embolization. With a catheter placed in the left internal mammary artery, an angiogram was performed which confirmed the AVM arising off the left internal mammary artery (LIMA, red arrow) connecting to the left internal mammary vein (LIMV, dashed purple arrow). Fig. 3b. The AVM was treated with nBCA glue mixed with Lipiodol in a 1:3 ratio which filled the LIMA and AVM nidus. Post-treatment angiogram via the left internal mammary artery demonstrates glue filling the LIMA (dashed red arrows) and no further filling of the AVM. Fig 4. Follow-up CT obtained one month post procedure demonstrates nBCA glue filling the LIMA (dashed red arrows) and complete resolution of the AVM.