Rescue thrombectomy in post-procedural FD thrombosis

• A 69-year-old female presented with intermittent severe headaches and an unruptured middle cerebral aneurysm discovered incidentally during an MRA study. DSA (Figure 1) confirmed the diagnosis. It was decided to proceed with flow diverter embolization using a p48 MW HPC 3x15mm. The procedure was uneventful, yielding optimal angiographic results (Figure 2)
• A few hours later, the patient presented with aphasia and right hemiplegia, resulting in an NIHSS score of 17

Figure 1

Figure 2

• CT and CTA showed left M1 occlusion of the MCA, and hypodensity of insula (Figure 3)
• DSA confirmed intraluminal stent occlusion at M1 tract of the left MCA (Figure 4)

Figure 3

Figure 4

Which is the most efficient treatment strategy?

1. Intra-arterial fibrinolytic
2. Thrombectomy
3. Intra-venous fibrinolytic
4. Gp IIb/IIIa inhibitors

Management, evolution, and follow-up

• The sheath catheter was positioned at the cervical tract of the left ICA. A SOFIA PLUS 6F catheter, along with a microcatheter and microguide, were advanced into the MCA. The SOFIA catheter was positioned at the proximal extremity of the flow diverter. However, the first passage using aspiration technique was unsuccessful (clips 1, 2, and 3).
• A second passage was attempted using aspiration technique with a SOFIA PLUS 6F catheter, which was successfully advanced inside the lumen of the flow diverter using a stentriever opened in the M2 tract (clip 4 and Figure 5). Angiographic control revealed recanalization of the occlusion (TICI 3) without any signs of flow diverter displacement (clip 5).
• At follow-up, CT scan showed ischemia of the basal ganglia and insula (Figure 6)

Clip 1

Clip 2

Clip 3

Clip 4

Clip 5

Figure 5

Figure 6

Technical Comments

• Advancing the Sofia catheter within the lumen of the flow diverter proved challenging. Consequently, a decision was made to deploy a stentriever distally at the M2 tract of the MCA, anchoring the Sofia catheter to it. This allowed for the Sofia catheter to advance inside the flow diverter lumen smoothly, without exerting pressure or displacing the flow diverter (Figure 5, clip 4). Subsequently, the stentriever was re-engaged in the microcatheter to prevent any friction within the flow diverter lumen, facilitating the aspiration thrombectomy
• Clips 1, 2, and 3, show the collapsing walls of the stent during the aspiration maneuver of the Sofia catheter; the stent remained undamaged after the procedure

Conclusion and key points

• Post-procedural thrombosis is a rare complication in FD implantation, but aggressive treatment with thrombectomy is feasible. Townsend et al. ¹ reported a favorable outcome in 88% of 10 cases treated with stent retriever, angioplasty, or intra-arterial thrombolytic infusion, without complications.
• From a technical perspective, Samaniego et al. ² performed stent retriever thrombectomy in two cases of PED occlusion. They fully opened the stent retriever inside the flow diverter and positioned the distal end of the stent retriever parallel and within the distal end of the PED to prevent displacement of the flow diverter. However, we opted to use the stent retriever as an anchor to facilitate entry of the SOFIA catheter into the FD lumen, minimizing stent friction during clot engagement.
• From a pharmacological standpoint, a histological study on the composition of clots in intrastent occlusions ³ suggests that GPIIb/IIIa inhibitors may be a preferable choice over fibrinolytics

References

1. Townsend RK, Wolfe SQ, Anadani M, Spiotta A, De Leacy R, Mocco J, Garner RM, Albuquerque FC, Ducruet AF, Kan P, Fargen KM. Endovascular management of acute postprocedural flow diverting stent thrombosis. J Neurointerv Surg. 2020 Jan;12(1):67-71. doi: 10.1136/neurintsurg-2019-014944 . Epub 2019 Sep 17. PMID: 31530652.
2. Samaniego EA, Dandapat S, Roa JA, Zanaty M, Nakagawa D, Hasan DM. Mechanical Thrombectomy of Acutely Occluded Flow Diverters. Oper Neurosurg (Hagerstown). 2019 Nov 1;17(5):491-496. doi: 10.1093/ons/opz023 . PMID: 30892631; PMCID: PMC7311826.
3. Larco JA, Abbasi M, Liu Y, Dai D, Lanzino G, Savastano LE, Cloft H, Kallmes DF, Kadirvel R, Brinjikji W. Postprocedural Thrombosis following Endovascular Treatment of Intracranial Aneurysm with Flow Diverters or Coiling: A Histologic Study. AJNR Am J Neuroradiol. 2022 Feb;43(2):258-264. doi: 10.3174/ajnr.A7369 . Epub 2021 Dec 16. PMID: 34916206; PMCID: PMC8985686.

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