First Experience of Three Neurovascular Centers With the p64MW-HPC, a Low-Profile Flow Diverter Designed for Proximal Cerebral Vessels With Antithrombotic Coating

Abstract

Background: In the last decade, flow diversion (FD) has been established as hemodynamic treatment for cerebral aneurysms arising from proximal and distal cerebral arteries. However, two significant limitations remain—the need for 0.027” microcatheters required for delivery of most flow diverting stents (FDS), and long-term dual anti-platelet therapy (DAPT) in order to prevent FDS-associated thromboembolism, at the cost of increasing the risk for hemorrhage. This study reports the experience of three neurovascular centers with the p64MW-HPC, a FDS with anti-thrombotic coating that is implantable via a 0.021” microcatheter.Materials and methods: Three neurovascular centers contributed to this retrospective analysis of patients that had been treated with the p64MW-HPC between March 2020 and March 2021. Clinical data, aneurysm characteristics, and follow-up results, including procedural and post-procedural complications, were recorded. The hemodynamic effect was assessed using the O'Kelly–Marotta Scale (OKM).Results: Thirty-two patients (22 female, mean age 57.1 years) with 33 aneurysms (27 anterior circulation and six posterior circulation) were successfully treated with the p64MW-HPC. In 30/32 patients (93.75%), aneurysmal perfusion was significantly reduced immediately post implantation. Follow-up imaging was available for 23 aneurysms. Delayed aneurysm perfusion (OKM A3: 8.7%), reduction in aneurysm size (OKM B1-3: 26.1%), or sufficient separation from the parent vessel (OKM C1-3 and D1: 65.2%) was demonstrated at the last available follow-up after a mean of 5.9 months. In two cases, device thrombosis after early discontinuation of DAPT occurred. One delayed rupture caused a caroticocavernous fistula. The complications were treated sufficiently and all patients recovered without permanent significant morbidity.Conclusion: Treatment with the p64MW-HPC is safe and feasible and achieves good early aneurysm occlusion rates in the proximal intracranial circulation, which are comparable to those of well-established FDS. Sudden interruption of DAPT in the early post-interventional phase can cause in-stent thrombosis despite the HPC surface modification. Deliverability via the 0.021” microcatheter facilitates treatment in challenging vascular anatomies.

Indirect Flow Diversion for Off-Centered Bifurcation Aneurysms and Distant Small-Vessel Aneurysms, a Retrospective Proof of Concept Study From Five Neurovascular Centers

“…This is contrasted by significantly lower complication rates reported by large-volume neurovascular centers ( 12 – 14 , 21 ) and underlines the importance of proper patient selection, treatment technique, and a patient-tailored, appropriate DAPT regimen ( 18 , 22 ). The results of the latter studies are in line with our experiences with the use of flow-diverting stents for treatment of bifurcation aneurysms, showing good safety and efficacy with low complication rates, especially when applying flow-diverting stents with anti-thrombotic coatings ( 11 , 23 ).…”

“…Furthermore, the most appropriate DAPT combination and its optimal duration must be determined in context of indirect flow diversion. As reflected by recent reports, the choice of the anti-platelet medication is a crucial determinant of the rate of ischemic and hemorrhagic complications in flow diversion ( 26 ) and may influence the time point of aneurysm occlusion as well ( 11 ). From a current perspective, the combination of ASA and Ticagrelor appears to be superior to ASA and Clopidogrel ( 22 ), although single anti-platelet therapy (SAPT) with Prasugrel only has shown promising results in combination with anti-thrombotically covered flow-diverting stents ( 31 ).…”

“…The common therapeutic tenets are (a) inducing thrombosis within the aneurysm and (b) creating complete remodeling of the parent artery via providing a solid scaffold for the development of a neointima at the aneurysm-parent artery interface (4)(5)(6). Each class of hemodynamic implant has a specific aptitude for certain types of aneurysms-endosaccular flow disruptors have proved to be especially valuable for the treatment of wide-necked bifurcation aneurysms at and distal to the Circle of Willis (3,7), whereas flow-diverting stents are considered the treatment of choice for wide-necked sidewall aneurysms (8) and non-saccular aneurysms (9)(10)(11). Flow-diverting stents have also been used for off-label indications, such as the treatment of bifurcation aneurysms (12)(13)(14), but unsatisfactory aneurysm occlusion in a number of cases, together with ischemic and hemorrhagic complications, remains a concern according to some investigators (15,16).…”

Endovascular treatment of intracranial vertebral artery unruptured dissecting aneurysms: Comparison of flow diversion and stent-assisted coiling or stenting alone

“…In the use of flow diverters or intracranial stents to treat cerebral aneurysms, dual antiplatelet therapy is necessary to prevent stent-related thromboembolic events. Recently, an anti-thrombotic polymer coating has been developed for coating a flow diverter (the p48MW HPC), and this coated flow diverter allows application of a single antiplatelet function medication for endovascular treatment of cerebral aneurysms, especially ruptured ones ( 34 – 36 ). Recent exploring studies have proved that deployment of this coated flow diverter is able to decrease thrombogenicity safely and effectively, and achieves good early aneurysm occlusion rates in cerebral aneurysms in the proximal intracranial circulation, complex bifurcation aneurysms in the anterior and posterior circulation, and distally located cerebral aneurysms even though further larger comparative studies are essential to confirm these outcomes and optimize the perioperative antiplatelet treatment ( 34 – 36 ).…”

Safety and efficacy of the p48 MW and p64 flow modulation devices: a systematic review and meta-analysis

“…Ten studies were conducted in Germany, 9,11,14,[22][23][24][25][26][27][28] 2 in France, 8,29 3 in Belgium 12,13 (1 shared a location with Portugal 30 ), 2 in Mongolia, 31,32 and the remaining in Argentina, 25 Bulgaria, 33 and Italy. 34 Details about the location of the studies are shown in Fig.…”