Distal Flow Diversion with Anti-Thrombotically Coated and Bare Metal Low-Profile Flow Diverters-A Comparison

Abstract

Background and purpose: The establishment of low-profile flow diverting stents (FDS), for example, the Silk Vista Baby (SVB) and the p48MW, facilitated endovascular treatment of peripheral cerebral aneurysms. This study therefore aims to compare the performance and outcomes of the SVB with those of the p48MW HPC, with a special focus on hemodynamic aspects of peripheral segments and bifurcations.

Materials and methods: The study cohort comprises 108 patients, who were either treated with the SVB or the p48MW HPC between June 2018 and April 2021.

Results: Sixty patients received a SVB and forty-eight patients a p48MW HPC. The SVB was used predominantly in the AcomA-complex, and the p48MW HPC in the MCA bifurcation. Immediately after implantation, significant hemodynamic downgrading (OKM A2-A3, B1-B3, C3) was achieved in 60% in the SVB group vs. 75.1% in the p48MW HPC group. At the second follow-up, after an average of 8.8 and 10.9 months, respectively, OKM D1 was observed in 64.4% of the SVB group vs. 27.3% in the p48MW HPC group. Only 1.7% vs. 6.8% of the aneurysms remained morphologically unaltered (OKM A1). Adverse events with persisting neurologic sequalae at last follow-up were largely comparable in both groups (5.0% vs. 4.2%).

Conclusion: Immediately after implantation, the p48MW HPC had a more profound hemodynamic impact than the SVB; however, early complete occlusions were achieved in a greater proportion of lesions after implantation of the uncoated SVB.

Keywords: Silk Vista Baby; coating; flow diversion; low-profile flow diverter; p48MW; small cerebral vessels.

Figure 1

Shows the endovascular therapy of an incidental aneurysm in the distal ACA with the Silk Vista Baby flow diverter. (A) The reconstructed 3D angiogram demonstrates a saccular, broad-based aneurysm arising from the left-handed distal ACA at the level of the pericallosal artery. (B) Conventional DSA in working projection prior to the FDS implantation. (C) The SVB was implanted without any technical obstacles; however, diminished opacification of the covered callosomarginal artery was observed immediately afterwards and required rescue treatment with a GPIIb/IIIa inhibitor. (D) Correct position and complete wall adaptation of the implanted device sufficiently covering the aneurysm neck. (E) After administration of a body-weight adapted bolus of Eptifibatide intravenously, the control angiogram showed restored perfusion of the covered branch and the downstream territory. In the aftermath of the intervention, the patient did not suffer from neurological deficits. (F) At the first angiographic follow-up three months after FDS implantation, the covered segment shows distinct narrowing and the target aneurysm is completely occluded (OKM D1).

Figure 2

Shows the primary treatment of an irregular-shaped aneurysm arising from the right-hand side MCA trifurcation using the p48MW HPC: (A) The reconstructed 3D angiogram demonstrates the broad neck of the aneurysm completely comprising the MCA trifurcation segment. (B) Initial angiogram in working projection prior to the intervention. The posterior–anterior view is presented in the upper right corner. (C) After successful implantation of the p48MW HPC with the distal landing zone at the dominant superior trunk. The white arrow indicates the proximal landing zone, and the black arrow shows the distal ending of the FDS. Control injection confirmed the timely perfusion of the complete MCA territory without any delay in perfusion. (D) At the first angiographic follow-up, the opacification of the aneurysm remained unaltered (OKM A1); moreover, the side branches do not reveal any significant morphological changes. (E) At the second follow-up nine months after the FDS implantation, a significant reduction in aneurysm size with only residual opacification of the aneurysm neck was observed, corresponding to OKM C1. The perfusion of the covered MCA branches remained unaltered. (F) At the last available follow-up, 18 months after the treatment, the aneurysm was completely excluded from the intracranial circulation, while the covered M2 branches all remained intact.