Minimally Invasive Segmental Artery Coil Embolization (MISACE) for Spinal Cord Preconditioning in Thoraco-abdominal Aneurysm Repair. Lessons Learned in >100 Cases

Learning Objectives: 1. Indications for intercostal artery embolization
2. Current data and clinical trials on this subject
3. Tips and tricks for successful procedure
4. When not to do it
5. What to expect after the embolization

Background: Spinal cord ischemia (SCI) remains a feared complication that occurs with variable frequency reaching 10–20% despite various neural protective measures [1–5]. The vascular network of the spinal cord is comprised of contributions from the anterior spinal artery, radiculomedullary artery, and a network of anastomotic branches from the vertebral, subclavian, intercostals, lumbar, and the internal iliac arteries [1]. The spinal collateral network concept has been examined in experimental models and demonstrated an increase in the diameter of arterial vessels to the spinal cord after segmental arterial occlusion [7].

Clinical Findings/Procedure Details: MISACE was performed under conscious sedation with local anesthetic using a transfemoral approach. Anti-hypertensive medications were discontinued for few days prior to procedure. Target vessels were identified as intercostal or lumbar arteries >2mm, as seen on pre-operative CTA, in the territory of anticipated coverage during future open or endovascular TAAA repair. Anatomical landmarks were used to assist in intra-procedural vessel origin selection. Fusion software was used when available. Once a target vessel was selected, selective angiography was performed to visualize the vessel anatomy. Coil embolization was then performed in the proximal-most segment of the artery prior to any branch points, to allow for retrograde perfusion of the distal artery via the collateral network. Only embolic coils were used as embolic agent. As many arteries as possible were embolized limited by procedure time and contrast usage. Vast majority of cases were performed as single session as day case.

Conclusion and/or Teaching Points: The evidence for this technique is limited but increasing rapidly due to adoption of this procedure in many aortic centers. It is a technically challenging procedure due to anatomical reasons. Interventional radiologists routinely perform embolization, therefore are well suited to be involved in this field.
Case planning and selection are critical to ensure success. Gentle catheter skills are essential to minimize risk of dissection or atherosclerotic embolization. Proximal coils placement is essential for collateral developments.

In this presentation, we will be sharing our experiences of over > 100 cases of MISACE, emphasizing on patients selection, case planning, technical tips and management of complications.