Permanent intracranial stenting offers a feasible, safe ‘bailout’ option following a failed mechanical thrombectomy procedure. This was the concluding message delivered recently by Sarah Power (Beaumont Hospital, Dublin, Ireland)—who highlighted stenting’s association with improved successful recanalisation rates (thrombolysis in cerebral infarction [TICI] 2b–3 of 65–100%); positive functional outcome rates (modified Rankin Scale [mRS] 0–2 of 34–49%); and acceptable rates of symptomatic intracranial haemorrhage (sICH; 5–12%), in the current literature.
Speaking at the Barts Research and Advanced Interventional Neuroradiology (BRAIN) conference (5–8 December 2022, London, UK), she posited that the current literature details multiple potential rescue strategies following a failed thrombectomy. These include intra-arterial injection of thrombolytic agents or glycoprotein 2b/3a inhibitors; angioplasty with or without a drug-eluting balloon; and rescue stent insertion, with Power opting to focus on the third of these options.
Drilling down into the existing literature on rescue stenting, the speaker noted that there are no randomised controlled trials (RCTs) assessing this approach, and only a handful of prospective studies, with a preponderance of observational and retrospective research having been conducted to date. However, she continued, there are four systematic reviews and meta-analyses available on this topic.
The most recent of these was published in Interventional Neuroradiology in 2020, and compared rescue stenting with medical care alone in refractory large vessel occlusion (LVO) patients across Europe and Asia. Power reported a “very high” successful recanalisation rate of 65–92% following stenting in this study, as well as a significantly higher rate of good outcomes and lower mortality rates at 90 days in the stenting group versus the control group.
“There was no significant difference in the rate of sICH,” she added, “but, interestingly, there was a trend towards an increased rate [of sICH] in the control group.”
Here, Power highlighted a trend in this particular study, but also across many others, towards glycoprotein 2b/3a inhibitors being used consistently as a bolus in the intraprocedural phase, later stating that this was the “biggest surprise” she encountered within the existing literature.
The speaker then moved on to two further publications from 2019—a systematic review in World Neurosurgery assessing rescue stenting after failed thrombectomy or high failure risk thrombectomy, and a systematic review and meta-analysis in the Journal of NeuroInterventional Surgery evaluating the safety and efficacy of bailout stenting after failed thrombectomy. Across the global patient populations in both of these studies, high rates of successful recanalisation (79% and 71%, respectively) were observed with stenting, and stenting use corresponded to improved functional outcomes without increasing sICH or mortality rates.
Finally, Power alluded to a 2019 publication in Stroke that specifically looked at LVOs caused by atherosclerotic disease and largely included studies from Asia, noting that patients with underlying intracranial atherosclerosis (ICAS) were significantly more likely to experience intraprocedural re-occlusion (36.9% vs 2.7%), and require rescue balloon angioplasty (9% vs 1.3%) or stenting (37.8% vs 2.6%) after failed thrombectomy, in contrast to the analysis’ non-ICAS group.
Power also briefly outlined data from two registry studies that have been published recently—STAR (Stroke thrombectomy and aneurysm registry) and ReSET (Rescue stenting for failed endovascular thrombectomy). Via comparisons with matched cohorts from the medical arms of multiple stroke thrombectomy RCTs, the former demonstrated improved outcomes with no significant increases in early-timepoint haemorrhagic events when stenting was used, while the latter produced successful recanalisation and favourable outcome rates of nearly 99%, and 66%, respectively, and found that the bailout stent remained patent at follow-up in 82% of cases.
“Is permanent stenting [after] failed thrombectomy feasible?” the speaker queried. “I think, if we look at the literature, the answer to that is yes. We do not have RCT data but what we do have seems to suggest this is something that can help us in failed thrombectomy cases.”
Power went on to note that the literature also indicates that rescue stenting appears to improve successful recanalisation rates as compared to both the medical arms of major stroke RCTs and patients who do not receive stent implantation—and the same can be said for functional outcome rates too.
“Are the risks acceptable?” she continued. “I think that they are, and we also know from the meta-analyses that the rates of sICH are in fact higher in patients who were not treated with stents.”
Power concluded by making an “important point”, which is that—prior to rescue stenting—operators should use an angiographic run to ensure there is flow present through the occluded vessel when the stentriever is deployed, and perform on-table computed tomography (CT) to evaluate for intracranial haemorrhage as well.